Programming Manual

33124.mx-20 HoTT.1.en

HOPPING.TELEMETRY.TRANSMISSION

mx-20
2 Table of contents

Transmitter initialization ............................................... 38

Firmware update ................................................... 39

Receiver initialization ................................................... 42

Firmware update ................................................... 43

Installation notices ....................................................... 46

Receiver system power supply .............................. 47

Term defi nitions ........................................................... 50

Switch and control assignments .................................. 52

Digital trimming ............................................................ 54

Winged models ............................................................ 56

Receiver layout ...................................................... 57

Helicopter models ........................................................ 58

Receiver layout ...................................................... 59

Program descriptions

Loading a new memory location .................................. 60

"Model select" ............................................................ 63

"Copy / Erase" ............................................................ 64

Erase model .......................................................... 64

Copy model  model ........................................... 64

Export to SD card .................................................. 65

Import from SD card .............................................. 66

Copy fl ight phase ................................................... 66

"Suppress menus" ..................................................... 67

"Suppress models" .................................................... 67

"Base setup model"

Winged model ....................................................... 68

Model name .................................................... 68

Stick mode ...................................................... 68

Bound receiver ................................................ 68

Binding receivers ............................................ 69

Receiver output ............................................... 70

RF transmit ...................................................... 71

Range test ....................................................... 71

DSC output...................................................... 72

General notices

Table of contents ........................................................... 2

Environmental protection notices .................................. 3

Safety notices ................................................................ 4

Safety notices and handling regulations 

for nickel-metal-hydride rechargeable batteries ............. 8

Foreword ...................................................................... 10

Remote control set description .................................... 11

Recommended chargers ............................................. 13

Transmitter power supply ............................................. 14

Receiver power supply .......................................... 16

Joystick length adjustment........................................... 17

Opening the transmitter housing ................................. 17

Changing joystick behavior .......................................... 18

Transmitter description ................................................ 20

Operating elements ............................................... 20

Backside of the transmitter .................................... 21

Headset connector ................................................ 21

Mini-USB connector .............................................. 21

Data jack ............................................................... 21

DSC (Direct Servo Control) ................................... 22

Data storage / card slot ......................................... 22

Display and keypad ............................................... 24

Operating the "data terminal" ................................ 25

Shortcuts ............................................................... 26

Hidden menu columns ........................................... 27

Hidden mode ......................................................... 28

Language selection and display contrast .............. 28

Joystick calibration ................................................ 29

Telemetry data display ........................................... 32

Displayed warnings ............................................... 36

Function fi eld displays ........................................... 37

Position display for rotary controls, CTRL 7 & 8 .... 37

Entry lockout .......................................................... 37

 Table of contents

Cut-off ............................................................. 72

Helicopter model ................................................... 74

Model name .................................................... 74

Stick mode ...................................................... 74

Bound receiver ................................................ 74

Binding receivers ............................................ 75

Receiver output ............................................... 76

RF transmit ...................................................... 77

Range test ....................................................... 77

DSC output...................................................... 78

Autorotation ..................................................... 78

Auto.C1 Pos. .................................................... 79

Cut-off ............................................................. 79

"Model type" ............................................................... 82

"Helicopter type" ........................................................ 86

"Servo adjustment" .................................................... 90

"Stick mode"

Winged model ....................................................... 92

Helicopter model ................................................... 94

"Control adjust"

Winged model ....................................................... 96

Helicopter model ................................................. 100

 Throttle limit function ...................................... 104

 Idle setting ...................................................... 105

 Throttle limit in combination with AR in the 

"Stick mode" menu ...................................... 107

"Dual Rate / Expo"

Winged model ..................................................... 108

Helicopter model ................................................. 112

"Channel 1 curve"

Winged model ..................................................... 116

Helicopter model ................................................. 119

"Switch display" ....................................................... 122

"Control switch" ....................................................... 123

How do I program a fl ight phase? .............................. 126
Table of contents 3

"Phase settings"

Winged model ..................................................... 128

Helicopter model ................................................. 132

"Phase assignment" ................................................ 134

"Phase trim" (winged model) .................................... 136

"Non-delayed channels" .......................................... 137

"Timers (general)" .................................................... 138

"Flight phase timers" ............................................... 142

What is a mixer? ........................................................ 145

"Wing mixers" ........................................................... 146

"Helicopter mixer" .................................................... 164

Adjusting the throttle and pitch curve .................. 175

Autorotation setting ............................................. 178

General remarks about freely progr. Mixers .............. 180

"Free mixers" ............................................................ 181

Linear mixers ...................................... beginning 185

Curve mixer ........................................ beginning 187

Examples............................................................. 190

"MIX active/phase" ................................................... 192

"Mix Only Channel" .................................................. 193

"Dual mixer" .............................................................. 194

"Swashplate mixer" .................................................. 196

"Fail-safe" ................................................................. 196

"Teacher / pupil" ....................................................... 198

Connection schematic ......................................... 201

Wireless HoTT system ........................................ 202

"Tx. output swap" ..................................................... 206

"Telemetry" ...............................................................208

Setting& Data View .............................................. 209

Satellite operation of two receivers .............. 218

Sensor Select ...................................................... 220

RF Status View .................................................... 221

Voice Trigger ........................................................ 222

"Basic Settings" ....................................................... 224

"Servo display" ......................................................... 230

"Servo test" ............................................................... 231

"Code lock" ............................................................... 232

"Info display" ........................................................... 234

Programming examples

Introduction ................................................................ 236

Winged model

First steps ............................................................ 238

Incorporating an electric drive ............................. 244

C1 joystick switchover between

electric motor and butterfl y ............................ 247

electric motor and airbrake ............................ 250

Timer activation by control or switch ................... 252

Parallel operating servos ..................................... 254

Using fl ight phases

Example 1 ..................................................... 256

Example 2 ..................................................... 260

Control of temporal processes ............................ 266

Eight-fl ap wing ..................................................... 268

Delta and fl ying wing models ............................... 272

F3A model ........................................................... 276

Helicopter model ........................................................ 280

Appendix

Appendix .................................................................... 290

FCC Information ........................................................ 293

Declaration of Conformity .......................................... 294

Warranty Certifi cate ................................................... 295

 Environmental protection notices

The symbol on this product, its operating instructions 

or packaging gives notice that this product may not 

be discarded as common household waste at the end 

of its service life. It must be turned over to a recycling 

collection point for electric and electronic apparatus. 

The materials can be recycled according to their 

markings. You make an important contribution to 

protection of the environment by utilizing facilities for 

reuse, material recycling or other means of exploiting 

obsolete equipment. 

Batteries must be removed from the unit and disposed 

of separately at an appropriate 

collection point.

Please inquire with local authorities 

about the responsible waste collection 

locations.

This manual serves only as a source of information and 

can be changed without prior notifi cation. Graupner

accepts no responsibility or liability for errors or 

inaccuracies which may be contained in the information 

section of this manual.
4 Safety notices

In order to enjoy your modeling hobby for a long time, 

please read these instructions thoroughly and give 

particular attention to the safety notices. You should 

also register yourself at https://www.graupner.de/de/

service/produktregistrierung.aspx right away in order 

to automatically receive current information per email 

about your product.

If you are a beginner with remote controlled model 

aircraft, ships or cars, you should really ask an 

experienced model pilot for assistance.

If this remote control system changes ownership, these 

instructions should surely be included with remote 

control system.

Intended usage

This remote control system may only be used for the 

purpose intended by the manufacturer - specifi cally - for 

the operation of unmanned remote controlled models. 

Any other usage is not permissible.

Safety notices

SAFETY IS NO ACCIDENT

and

REMOTE CONTROLLED MODELS ARE NOT 

TOYS

... because even small models can cause substantial 

property damage and/or personal injuries if they are not 

handled properly - even if caused by third parties. 

Technical defects of an electrical or mechanical nature 

can lead to unexpected startup of a motor and/or parts 

being hurled through the air to pose a danger of injury to 

you and to others.

Short circuit conditions are to be avoided absolutely! 

A short circuit condition may not only destroy parts 

of the remote control system but, depending on 

the circumstances and the battery energy involved, 

may also pose acute danger of incineration or even 

explosion.

All motor-driven parts, such as aircraft or ship 

propellers, helicopter rotors, open gearboxes etc. 

represent a constant danger. Contact with these parts 

must be avoided. A rapidly turning aircraft propeller 

can, for example, sever a fi nger. Also pay attention that 

other objects do not come into contact with driven parts.

When a drive battery is connected or a motor is running: 

never get into the danger zone of driving mechanisms.

Be sure to pay attention that motors do not start 

up unintentionally while performing programming 

operations. Disconnect the fuel supply or battery 

terminals to motors before programming.

Protect all units from dust, dirt, moisture and other 

foreign parts. Never expose these units to vibrations 

or excessive hot or cold temperatures. Remote control 

operation may only be performed under "normal" 

outdoor temperatures, i. e. within a range of -15 ° C to 

+55 ° C.

Avoid mechanical jarring and pressure stresses. Always 

check units for damage to housings and cables. Do not 

use units which have been damaged or become wet, 

even after they are dry again. 

Only those components and accessories which we 

recommend may be used. Always use original Graupner 

plug and jack connectors which are made for one 

another out of the same materials. 

When routing cables, pay attention that they are not 

stressed, unduly kinked or broken. The sharp edges 

of adjacent parts also represent a hazard for insulated 

conductors.

Be sure that all plug and jack connections are fi rmly 

seated. Do not pull on the cable to disconnect a plugged 

connector.

No modifi cations whatsoever may be made to units. 

Modifi cations will void the operating permit and all 

insurance protection.

Receiver installation

The receiver is to be installed with a cushion of foam 

rubber to afford protection against jarring; in aircraft 

models behind a strong rib, for a car or ship model the 

location must be protected against dust and spray water. 

The receiver may not be mounted in direct contact with 

the hull or chassis as this would allow motor vibrations 

and/or roadway jarring to be transferred directly to the 

receiver. When a receiver system is installed in a model 

with a combustion motor, all receiver parts should 

always be protected against the intrusion of exhaust 

gasses and oil residue. Above all, this applies to the 

model's ON/OFF switch, which is typically built into the 

model's outer surface.

Position the receiver such that connecting cables to 

the servos and the power supply are routed with a bit 

of slack and that the receiver's antenna is at least 5 cm 

away from any large metal parts or wiring except for 

other receiver wires/cables. In addition to steel, this also 

includes carbon fi ber parts, servos, electric motors, fuel 

pumps and all sorts of cables, etc. 

Preferably, the receiver should be mounted in a readily 

accessible location in the model that is well apart from 

all electrically operated units. Under no circumstances 

may a servo cable be wrapped around the antenna or 

routed close to it.

Make sure that cables near the antenna cannot move 

about during fl ight.

 Safety notices

Be sure to pay attention!
Safety notices 5

transmitter's antenna directly toward the model will not 

produce good reception but rather degrade reception.

When multiple remote controls are operating 

simultaneously, pilots should position themselves in a 

loose group. Pilots standing off to themselves not only 

endanger their own models but those of others as well. 

However, when 2 or more pilots using 2.4 GHz remote 

control systems are closer than 5 m to one another this 

can lead to return channel overdrive which, in turn, will 

trigger a range warning much too early. Increase your 

distance between one another until the range warning 

ceases.

Pre-start checks

Before switching the receiver on, ensure that the gas 

control is at its Stop/Idle position.

Always switch the transmitter on fi rst and then the 

receiver.

Always switch the receiver off fi rst and then the 

transmitter.

If this sequence is not maintained, such that the receiver 

is still switched on when the corresponding transmitter 

is switched to "OFF", then the receiver may respond to 

other transmitters or general radio frequency noise. This 

can cause the model to execute uncontrolled operations 

that may cause personal injuries and/or property 

damage.

In particular, for models equipped with a mechanical 

gyro: 

before switching off the receiver, disconnect the model's 

power supply to prevent the motor from revving up 

unintentionally. 

The residual spin of a gyro often produces so much 

voltage that the receiver may falsely interpret a 

throttle signal! This will then cause the motor to 

start up unexpectedly.

Range test

Perform checks for proper operation and range before 

every session. Secure the model adequately in place 

and ensure that no one is in front of the model.

Perform a complete functional test on the ground and 

execute a complete simulated fl ight to exclude the 

possibility of system faults or problems with the model's 

programming. When doing this, be sure to follow the 

notices provided on pages 71 and77.

Never operate the transmitter in Model mode, i.e. 

for fl ying or driving, without an antenna. Be sure the 

antenna is fi rmly seated in its socket. 

Operating a winged aircraft, helicopter, ship or car

Never fl y over spectators or other pilots. Never endanger 

humans or animals. Never fl y in the vicinity of highvoltage wires. Do not operate the model in the vicinity of 

sluice locks or where real boats or ships are operating. 

Do not operate a model on public streets or highways, 

paths or plazas, etc.

Monitoring transmitter and receiver batteries

You must stop running the model to recharge the 

transmitter's battery no later than when low transmitter 

battery voltage triggers the "Batt must be recharged!!" 

display and acoustic signal.

Check the charge in batteries routinely, particularly the 

receiver's battery. Do not wait until the movements of 

controlled mechanisms are noticeably slower. Replace 

expended batteries before they cause problems.

The battery manufacturer's charging instructions 

Routing the receiver's antenna

The receiver and its antennas must be positioned as far 

away as possible from drives of any kind. If the model's 

hull is made of carbon fi ber material, the ends of the 

antennas must extend outside of the hull.

The orientation of antennas is not critical. Nevertheless, 

a vertical (upright) installation of receiver antennas is 

advantageous. In the case of diversity antennas (two 

antennas), the second antenna should be oriented at a 

90° angle to the fi rst antenna. 

Servo installation

Always mount servos with the provided rubber vibrationdamper parts. Only in this manner can these parts be 

protected against excessively hard vibrations.

Installing control rods

Control rods must be installed such that they operate 

freely and smoothly. It is particularly important that all 

rudder levers are able to move to their full limits, i.e. not 

otherwise mechanically blocked.

In order to be able to stop a running motor at any time, 

control rods must be adjusted such that the carburetor 

tap is completely closed when the joystick and trim lever 

are brought into their end idle position.

Pay attention that no metal parts, e. g. as a result of 

rudder actuation, vibration, rotating parts, etc., rub 

against one another. Metal-to-metal contact causes 

electrical "noise" which can interfere with the correct 

operation of the receiver.

Transmitter antenna orientation

Transmission fi eld strength is minimal in an imaginary 

line extending straight out from the end of the 

transmitter's antenna. This means that "pointing" the 
6 Safety notices

are always to be followed, this includes mandatory 

adherence to the length of charging time. Never leave 

batteries being charged unattended.

Never attempt to charge primary batteries (nonrechargeable batteries) because they can explode.

All secondary batteries (rechargeable batteries) must 

be charged before every session. To avoid short circuit 

conditions, fi rst connect the charger cable's banana 

plugs, polarity correct, into the charger and thereafter 

connect the charger cable's plugs to the transmitter and 

receiver batteries. 

Disconnect all power sources from the model when it is 

not to be used for an extended period of time. 

Never attempt to use defective batteries, damaged 

batteries or mixed-type battery combinations as a single 

group. Do not use mixed combinations of old and new 

batteries or batteries of different manufacture.

Capacity and operating time

The rule: "capacity is reduced with every successive 

recharging", applies to all batteries. Internal resistance 

increases at low temperatures to further reduce capacity. 

As a consequence, the battery's ability to provide 

current and hold its voltage is reduced.

Frequent charging or the use of battery maintenance 

programs can also result in gradual loss of battery 

capacity. Therefore the capacity of batteries should be 

checked at regular intervals, not in excess of every six 

months, and replaced if performance is found to be 

signifi cantly defi cient.

Purchase only genuine Graupner batteries!

Interference suppression for electric motors

All conventional electric motors produce sparks between 

their collector and brushes. Depending on the type of 

motor involved, this may cause more or less interference 

with the functionality of the remote control system.

The electric motors of a properly built system should 

therefore have interference suppression features. 

For electric drive models it is particularly important 

that every one of its motors is provided with proper 

interference suppression. Interference fi lters extensively 

suppress such disturbances and should always be 

included. 

Follow the respective recommendations included in the 

motor's operating and installation notices.

For further details about interference fi lters, refer to the 

Graupner RC main catalog or in Internet at 

www.graupner.de.

Servo interference fi lters for extension cables

Order No. 1040

The servo interference fi lter is necessary when an 

extended-length servo cable is used. This fi lter is 

attached directly to the receiver output. In critical cases 

a second fi lter can be attached to the servo. 

Using electronic speed controllers

Choosing the right electronic controller is largely a 

matter of matching controller performance to the motor 

to be controlled.

In order to prevent an overload or damage to the speed 

controller, its current rating should be at least half of 

the maximum locked-rotor current draw of the motor to 

which it is connected.

Particular attention is appropriate for so-called "tuning 

motors". Because of their low-turns coils these motors 

can draw a multiple of their rated current in a lockedrotor condition and this can lead to the destruction of the 

speed controller.

Electric ignition systems

Combustion motor ignition systems also produce 

interference that can negatively infl uence remote control 

functionality.

Always supply power to an electric ignition system from 

a separate, dedicated battery.

Use only interference-suppressed spark plugs, spark 

caps and shielded ignition leads.

Mount the receiver suffi ciently far away from ignition 

system components.

Static charges

A remote control system will be destroyed by the 

magnetic shock waves produced by a lightning strike - 

even if the storm is miles away. Therefore ...

... stop fl ying right away if a storm is approaching. 

Static charging via the antenna also represents a 

lethal hazard.

Attention

• In order to fulfi ll FCC HF emission requirements for 

mobile transmitters, a distance of at least 20 cm 

must be maintained between this system's antenna 

and other persons when this system is operating. 

Operation of this system at a lesser distance is 

therefore not recommended. 

• To avoid disturbance caused by the electrical 

characteristics and emissions of other transmitters, 

keep at least a 20 cm distance from other 

transmitters.

• Operation of the remote control system requires a 

correct program setting for the given country in the 

transmitter unit. This is necessary for compliance with 

diverse regulations like FCC, ETSI, CE etc. Follow 

the respective instructions provided for this with the 

Safety notices
Safety notices

7

transmitter and receiver.

• Prior to every fl ight, perform a complete functional 

test, range test and execute a complete simulated 

fl ight in order to exclude the possibility of system 

faults or problems with the model's programming.

• Never program the transmitter or receiver while the 

model is being operated. 

Care and maintenance

Never clean the housing, antenna, etc. with cleaning 

agents, gasoline, water or similar means. Use only a dry, 

soft cloth.

Components and accessories

As manufacturer of this equipment Graupner GmbH 

& Co. KG recommends only components and 

accessories which have been tested and approved by 

Graupner for their suitability, functionality and safety. 

If this recommendation is followed, Graupner accepts 

responsibility for the product. 

Graupner cannot accept any responsibility for the 

parts or accessories of other manufacturers which 

have not been approved and Graupner cannot 

evaluate every individual product made by other 

companies to assess if they are safe to use.

Liability exclusion / damage compensation

This manual serves only as a source of information and 

can be changed without prior notifi cation. Graupner

accepts no responsibility or liability for errors or 

inaccuracies which may be contained in this manual.

Graupner cannot monitor compliance with the assembly 

instructions, the operating instructions or the conditions 

and methods under which remote control components 

are installed, operated, utilized or maintained. Therefore 

Graupner accepts no form of liability for loss, damage or 

costs consequential to incorrect usage or operation or 

which can be attributed to same.

Unless otherwise prescribed by law, the obligation of 

Graupner to provide damage compensation, regardless 

of legal grounds, is limited to the invoice value of the 

quantity of Graupner. goods contributing directly to the 

damage-inducing event. This does not apply if Graupner

is found to be subject to unlimited liability pursuant to 

binding legal stipulations with respect to intent or gross 

negligence. 
8 Safety notices

 Safety notices and handling instructions for nickel-metal-hydride rechargeable batteries

As applicable for all highly technical products, 

observance of the following safety notices, along with 

the handling instructions, is essential for a long service 

life, fault-free operation, and harmless utilization.

Safety notices

• Individual battery cells and batteries are not toys and 

must therefore not get into the hands of children.

Batteries/cells must be kept out of the reach of 

children.

• Batteries are to be checked for fl awless condition 

prior to every use. Defective or damaged cells/

batteries may no longer be used.

• Cells/batteries may only be utilized within the limits 

specifi ed by the technical data for the given battery 

type.

• Batteries/cells may not be heated, burned, shortcircuited or subjected to overload current or 

reverse polarity.

• Battery confi gurations formed by parallel 

connected cells, combinations of old and new 

cells, or cells of different production, size, 

capacity, manufacturer, brand or cell type may 

not be used.

• Remove batteries from the unit prior to long-term 

storage periods (weeks or months). Always switch 

off units whenever they are no longer in use (shortterm). Always charge batteries before it is too late.

• The battery to be charged must be placed on a noncombustible, heat resistant, non-conducting surface 

during the charging process. Combustible or readily 

ignited objects are to be kept away from the charging 

confi guration.

• Batteries may only be charged under supervision. 

The quick charge current rating for the given type of 

battery must never be exceeded.

• If the battery heats up during charging above 60 °C 

charging must be stopped immediately. Allow the 

battery to cool off to about 30 °C before resuming the 

charging process.

• Never charge batteries which are already charged, 

batteries which are hot or batteries which have not 

been discharged to their end-point voltage.

• No modifi cations may be made to the batteries. 

Never solder or weld directly on battery terminals.

• The mistreatment of batteries presents a danger of 

ignition, explosion, chemical burns and combustion 

burns. Use of an extinguishing blanket, CO2-fi re 

extinguisher or sand are suitable methods of 

extinguishing such a fi re.

• Leaking electrolyte is caustic; do not allow it 

to contact the skin or eyes. In the event of an 

emergency, immediately rinse with a generous 

amount of water and get the care of a doctor.

• Battery vent openings may never be blocked or 

sealed, e. g. by solder. Soldering temperature may 

not exceed 220 °C and not be applied for longer than 

20 seconds.

• To avoid deformation, do not exert excessive 

mechanical force.

• If a battery should become overcharged, proceed as 

follows:

Simply disconnect the battery and place it on a noncombustible surface (e. g. masonry fl oor) until it has 

cooled off. To avoid the hazards associated with an 

explosion, never hold the battery in your hands.

• Pay attention that the charging and discharging rules 

are followed.

General notices

Battery capacity is reduced by every charge/discharge 

cycle. Storage can also be cause for a gradual reduction 

of battery capacity.

Storage

Batteries should only be stored when they are not in a 

completely discharged condition. They should be stored 

in a dry room having an ambient temperature between 

+5 °C to +25 °C. When stored for longer than 4 weeks, 

cell voltage should not be more than 1.2 V.

Matching up individual batteries

• To match new batteries with older ones, put a full 

charge on all of the batteries using a standard 

charging process. As a rule of thumb, an empty

battery must be charged for 12 hours at a current 

rate equal to one tenth of its specifi ed capacity 

("1/10 C" method). The batteries are then all charged 

equally. Such a matching procedure should be 

repeated about every 10th charge cycle so that 

batteries are matched again, which contributes to 

longer battery life.

• If it is possible to discharge individual batteries, this 

should be done prior to every charging process. 

Otherwise the battery pack should be discharged 

to a voltage of 0.9 V per cell. For example, this 

corresponds to a charge voltage of 3.6 V for the 

4-cell pack used in the transmitter.

Charging

Charging is only permissible at specifi ed current rates, 

charging durations, temperature ranges and continuous 
Safety notices

9

supervision. If a suitable quick charger is not available 

on which the exact charging current can be set, the 

battery can be charged by standard charging according 

to the 1/10 C-method, see example above. 

Whenever possible, transmitter batteries should 

charged with the 1/10 C method because of the 

differing charge states of the cells. However, 

charging current may never be allowed to exceed 

the maximum permissible rate specifi ed in the given 

transmitter's instructions.

Quick charging

• If your charger offers this option then set the delta 

peak charge cutoff voltage to 5 mV per cell. However, 

most chargers are set to a fi xed value of 15 ... 

20 mV per cell so they can be used for both NiCd 

batteries as well as NiMH batteries If in doubt, fi nd 

out if your charger is also suitable for NiMH batteries 

by referring to the charger's operating instructions 

or consulting a dealership. If you are unsure, charge 

your batteries at half of the specifi ed maximum 

current rate.

Discharge

All batteries sold under the Graupner and GM-Racing

trade names are, depending on battery type, suitable for 

a continuous maximum current load of 6 ... 13 C (check 

the manufacturer's data). In general, the higher the 

continuous current load, the lower the battery's service 

life will be.

• Use your battery until its performance degrades or 

the under-voltage warning sounds. 

Attention:

A cell voltage of 1.2 V should not be underrun during 

a long storage period. If necessary, charge the 

battery before putting it into storage.

• Refl ex charging and charge/discharge programs 

unnecessarily shorten a battery's service life and are 

only useful in checking battery quality or to "revive" 

old cells. It is also meaningless to charge/discharge a 

battery before using it. The exception to this is if your 

intention is to check the battery's quality.

Disposal of used batteries

Some countries have laws requiring that all used 

batteries be turned over to an authorized collection 

center.

Disposing of batteries along with common household 

garbage is forbidden. Old batteries can be turned into 

communal collection centers for disposal at no charge 

or they can be returned to one of our dealerships or 

anywhere else where batteries of that given type are 

sold. Used batteries we have delivered can also be sent 

back to us, at your cost, through the mail. Use the return 

address below:

Graupner GmbH & Co. KG

Service: Used batteries

Henriettenstr. 94 - 96

D-73230 Kirchheim unter Teck

This represents an essential contribution to 

environmental protection.

Caution:

Damaged batteries require among other things, special 

packaging, because they are very toxic! 
10 Introduction

mx-20 the newest generation of remote control technology

HoTT (Hopping Telemetry Transmission) is a synthesis 

of know-how, engineering and testing done around the 

world by experienced model pilots. HoTT technology 

combines 2.4 GHz band transmission/reception with 

bi-directional communications via a "return channel" 

integrated into the receiver unit. 

Based on the Graupner/JR computerized remote 

control system mc-24 that was introduced in 1997, 

the mx-20 HoTT remote control system has been 

especially developed for experienced RC pilots All 

conventional model types can be readily operated 

with the mx-20 HoTT system, regardless of whether 

the model is a winged aircraft, helicopter, ship or land 

vehicle. 

Complex mixed-control functions of guiding surfaces are 

often necessary for winged aircraft (rudder, elevators) 

and helicopter models (swashplate). Thanks to this 

computer technology it is possible to activate these 

diverse functional requirements with a single "press 

of a button". Simply select the given model type from 

the mx-20 HoTT program and its software will 

automatically assemble signifi cant mixed-control and 

coupled functions. This eliminates the need for separate 

modules in the transmitter to implement complex 

coupled functions and also makes sophisticated 

mechanical mixer mechanisms in the model 

unnecessary. The mx-20 HoTT remote control system 

offers the highest level of safety and reliability. 

Its software is clearly structured. Functionally-related 

options are clearly arranged by content in a simple 

organization.

The mx-20 HoTT remote control system has 24 

model memory locations. Additional fl ight-phase-specifi c 

settings can be stored in every model memory location. 

For example, such settings can be made for various 

parameters that can be called up to implement particular 

fl ight maneuvers at the "press of a button". 

The large graphic display is well organized and simple 

to operate. The mixer's graphic representation is 

exceptionally helpful. 

Familiarization with the various functions in this remote 

control system is quick, even for a beginner, because 

of its clear, straightforward program structure. The user 

makes his settings with the four-way, touch sensitive 

buttons located to the left and right of the high-contrast 

display. Thus, with only little practice, the pilot learns to 

implement all of the remote controlled model options 

with which he/she has experience.

This Graupner HoTT technique theoretically allows over 

200 models to be operated simultaneously However, 

because of the interspersed radio-frequency utilization 

permitted by certifi cation for the 2.4 GHz ISM band, this 

number is signifi cantly lower in practical application. 

Nevertheless, in general more models can be operated 

simultaneously in the 2.4 GHz band than would be the 

case in conventional 35 or 40 MHz frequency bands. 

The real limiting factor is – as often before – is still likely 

to be the size of available operating space (i.e. airspace 

for aircraft). Alone the fact that it is no longer necessary 

to coordinate transmitting frequencies with other pilots in 

the vicinity (which is sometimes quite diffi cult in broken 

landscapes, such as on hillside slopes) represents an 

enormous boost for remote control operating security.

The integrated telemetry menu affords simple access 

to data and HoTT receiver programming. For example, 

this can be used to map receiver outputs, assign control 

functions to multiple servos, and to coordinate the 

magnitude and direction of multiple servo movements 

with one another. 

This handbook describes every menu in detail. There 

are tips, many notices and programming examples to 

supplement the descriptions and also explanations for 

model specifi c technical terms, like transducer, dual 

rate, butterfl y, etc.

An appendix is provided which contains additional 

information about the HoTT system. This manual is 

rounded out with the conformity declaration and the 

guarantee certifi cate for the transmitter.

Please observe the safety notices and technical notices. 

Read the instructions carefully then test all functions by 

simply attaching servos to the receiver included in the kit 

for order no. 33124. When doing this, please observe the 

corresponding notice provided on page 20. This will help 

you learn the essential operating steps and functions of 

the mx-20 HoTT in the least amount of time.

Always handle your remote controlled model with a 

sense of responsibility so that you do not endanger 

yourself or others.

The Graupner team wishes you much fun and success 

with your mx-20 HoTT remote control system of the 

newest generation

Kirchheim-Teck, September 2011
Introduction - Remote control set 11

 Computer System mx-20

12 channel remote control s et in 2.4 GHz Graupner HoTT technology (Hopping Telemetry Transmission)

The superior functional security of Graupner

HoTT technology accomplished with bidirectional 

communications between transmitter and receiver 

with integrated telemetry, freely programmable 

voice output via headset connector, and ultra-fast 

response times.

Programming is simplifi ed by a programming 

technique implemented with capacitive touch 

buttons. 

High contrast, 8 line, blue illuminated graphic 

display for perfect presentation of all parameter 

settings and telemetry data. Storage of telemetry 

data on a micro SD memory card.

Integrated real time clock 

4096 steps of 12-bit resolution on the channel signal 

assures extreme control sensitivity.

USB connection to read and write the model's 

memories as well as for making fi rmware updates. 

• Microcomputer remote control system in modern 

2.4 GHz Graupner HoTT technology

• Bidirectional communications between transmitter 

and receiver

• Five different languages:

German, English, French, coming soon per software 

update Italian and Spanish.

• Ultra fast response times due to reliable, direct 

transmission of data from the main processor to the 

2.4 GHz HF module. No additional delays due to 

routing over a module processor.

• Telemetry menu for display of telemetry data and 

for programming optional attachment sensors and 

receiver outputs

• The telemetry screen provides many programming 

and evaluation functions to be presented directly in 

the transmitters display

• Voice output can be called up via freely 

programmable switches

• Digital servo cycle times of 10 ms selectable

• Short antenna, collapsible

• Operating and programming techniques are similar 

to the proven concepts implemented in mc-19 to 

mc-24

• High contrast, blue illuminated graphic display 

assures perfect control of parameter settings like 

model type, model memory, clocks and operating 

voltage.

• Function encoder with two touch-sensitive, four-way 

buttons permit simplifi ed programming and precise 

settings

• Key-lock function to prevent unintentional operation.

• 7 fl ight phases can be programmed
12 Introduction - Remote control set

• 24 model memories with storage for all modelspecifi c programs and parameter settings

• 7 switches (2 three stage switches, 3 two stage 

switches and 2 touch switches) and 3 digital 

actuators are already built-in and can be used as 

desired

• Free assignment of switches to switched functions by 

simply switching the desired switch 

• Simple programming of motor and brake switchover 

for electric gliders on the K1 joystick.

• Internal realtime clock for time-stamping log fi les

• User-replaceable CR2032 buffer battery for the 

internal realtime clock

• Model memory storage in a modern, non-volatile 

backup system

• 12 control functions with simplifi ed arrangement 

of operating elements for supplementary functions 

like switches and proportional transducers make 

operating convenient

• Convenience mode selector for simplifi ed switchover 

between MODES 1 ... 4 (Gas left/right, etc.)

All affected settings are also automatically switched 

over.

• Graphic servo position display for fast, simple 

overview and for checking servo movements

• Transmitter output swapping

• Extensive programs for winged aircraft and helicopter 

models:

Winged aircraft menu for: 1 QR, 2 QR, 2 QR + 1, 2 

and 4 WK as well as 4 QR + 2 and 4 WK, V tail unit, 

delta/all-wing, 2 elevator servos

Surface mix: QR-diff, WK-diff, QR  SR, QR 

WK, brake  HR, brake  WK, brake  QR, HR 

 WK, HR  QR, WK  HR, WK  QR and diff. 

reduction

Heli menu for: 1-, 2-, 3- and 4-point linkage (1 Sv, 

2 Sv, 3 Sv (2 roll), 3 Sv (140°), 3 Sv (2 nick), 4 Sv 

(90°))

• 8 linear mixers, 4 curve mixers and 4 16 free mixers, 

cross mixers

• Swashplate limiter

• ±150 % servo adjustment for all servo outputs, 

independently adjustable per side (Single Side Servo 

Throw)

• Sub-trim in the ±125 % range for setting all neutral 

servo positions

• Servo reverse can be programmed for all servos 

• Two stage DUAL RATE/EXPO system, individually 

adjustable for specifi c fl ight phase and switchable 

during fl ight 

• Stop watches/countdown timers with alarm function

• Copy function for model memory

• Built-in DSC jack for connecting fl ight simulators or a 

teacher/pupil system

• Envisioned for a later update:

Voith-Schneider limiter, works similar to a swashplate 

limiter 

Door sequencer, e. g. for putting down landing gear 

automatically or retractable powerplant with runout 

controller

Nautical program

General HoTT features

• Maximum noise immunity due to optimized frequency 

hopping and wider channel spread

• Intelligent data transfer with correction function

Computer System mx-20

12 channel remote control set with 2.4 GHz Graupner HoTT technology (Hopping Telemetry Transmission)

• Realtime telemetry evaluation

• Over 200 systems can be used simultaneously

• Update capability via USB interface guarantees 

future viability

• Simple, very fast transmitter to receiver binding

• in parallel Binding with multiple receivers per model 

operation is possible

• Extremely fast rebinding, even at maximum distance

• Range test and warning function

• Receiver under-voltage warning in the transmitter's 

display

• Extremely wide receiver operating voltage range of 

3.6 V to 8.4 V (fully functional to 2.5 V)

• Failsafe

• Arbitrary channel assignment (channel mapping), mix 

functions and all servo settings can be programmed 

in the telemetry menu 

• Up to 4 servos can be controlled simultaneously as 

a block at a servo cycle time of 10 ms (digital servos 

only)
Introduction - Remote control set 13

mx-20 HoTT technical data

Frequency band 2.4 ... 2.4835 GHz

Modulation FHSS

Transmit power see country setting, page 227

Control functions 12 functions, 4 of these can 

be trimmed

Temperature range -10 ... +55 °C

Antennae collapsible

Operating voltage 3.4 ... 6 V

Current draw about 180 mA

Dimensions about 190 x 195 x 90 mm

Weight about 770 g with transmitter 

battery

Accessories

Order No. Description

1121 Neck strap, 20 mm wide

 70 Neck strap, 30 mm wide

3097 Hand transmitter wind protection

 Teacher/pupil cable for mx-20 HoTT 

see page 201

Replacement parts

Order No. Description

2498.4FBEC 4NH-2000 RX RTU fl at

33800 HoTT transmitter antenna

Technical data, receiver GR-24 HoTT

Order No. 33512

Operating voltage 3.6 ... 8.4 V*

Current draw about 70 mA

Frequency band 2.4 ... 2.4835 GHz

Modulation FHSS

Antenna Diversity antennas, 

2 x about 145 mm long, 

about 115 mm encapsulated 

and about 30 mm active

Plug-in servos 12

Plug-in sensors 1

Temperature range about -10 ... +55 °C

Dimensions about 46 x 31 x 14 mm

Weight about 16 g

* The specifi cation for permissible operating voltage range applies 

only to the receiver. Please note in this context that receiver input 

voltage is applied without regulation to connected servos but the 

voltage range for most connectible servos (speed controls, gyros, 

etc.) is only 4.8 to 6 V.

The Order No. 33124 set includes

Microcomputer transmitter mx-20 HoTT with builtin NiMH transmitter battery 4NH-2000 RX RTU fl at 

(change reserved), plug-in charger and Graupner

bidirectional receiver GR-24 HoTT. 

 Recommended charger units (accessories)

Order

No. Designation

Input voltage 220 VInput voltage 12 V

appropriate for 

the following 

batteries

NiCdNiMHLiPolead batteryintegr. balancer

6411 Ultramat 8 x x x x x

6463 Ultramat 12 plus x x x x x x

6424 Ultramat 14 plus x x x x x x x

6466 Ultra Trio plus 14 x x x x x x x

6468 Ultramat 16S x x x x x x x

6469 Ultra Trio Plus 16 x x x x x x

6470 Ultramat 18 x x x x x x x

6475 Ultra Duo Plus 45 x x x x x x x

6478 Ultra Duo Plus 60 x x x x x x x

6480 Ultra Duo Plus 80 x x x x x x x

Transmitter charger cable, order no. 3022 and receiver charger cable, 

order no. 3021 are also needed to charge batteries.

Other charger units and details about the listed chargers can be found 

in the Graupner RC main catalog or in Internet at www.graupner.de.

Other accessories are listed in the appendix or can 

be found in Internet at www.graupner.de. Feel free 

to contact your dealer too. He will be glad to provide 

advice.
14 Operating notices

 Operating notices 

 Transmitter power supply

The mx-20 HoTT transmitter has a highly capacitive, 

rechargeable NiMH battery, 4NH-2000 RX RTU (Order 

no. 2498.4FBEC), as standard equipment. (changes 

reserved) However, the standard built-in battery is 

not charged upon delivery of the transmitter.

When the transmitter is used, its battery voltage 

should be monitored by way of the indicators provided 

in the LCD display. If battery voltage drops below 

the adjustable voltage setting (set via item "Batterie 

warning" in the "Basic Settings" menu, page 226,), 

default value 4.7 V, an audible warning signal will sound 

and the message window shown below will appear in 

the screen 

GRAUBELE

#01

0:22h

Stop

Flug

«normal »

K78

0:00

0:00

0.0V

4.6V10%

x Mx

HoTT

battery

needs

charging

No later than now, operation must be terminated so the 

battery can be charged again. 

Notice:

Be sure that the correct battery type is set in the "Basic 

Settings" menu, page 224! NiMH must be set as 

standard.

 Charging the transmitter's battery

The transmitter's rechargeable NiMH battery can be 

recharged by connecting the charging jack located, 

on the right side of the transmitter, with the included 

charger (order no. 33116.2).

As a rule of thumb for charging time, an completely 

discharged battery will require 12 hours to recharge at a 

current rate equal to one tenth of its specifi ed capacity. 

For the standard transmitter battery and included 

charger, this is a current rate of 200 mA. However, 

you must yourself ensure that the charging process is 

terminated when it should be ...

The transmitter must be switched "OFF" during 

the entire charging procedure. Never switch on the 

transmitter when it is connected to the charger. Even 

a brief interruption to charging can cause charging 

voltage to rise to a level that will immediately damage 

the transmitter with over-voltage. Also for this reason, be 

sure all connectors are always plugged in securely and 

have good contact. 

mx-20 HoTT charging jack polarity

The charger cables on the market from other 

manufacturers often have different polarities. Therefore use 

only an original Graupner charger cable, order no. 3022.

Charging with automatic chargers

The transmitter's charger jack does come standard 

with reverse polarity protection but nevertheless it can 

be used with suitable chargers for quick charging the 

transmitter's battery.

Set the quick charger unit, according to its manual, for 

a delta peak voltage difference of 5 mV ... 20 mV or 

equivalent such that it is adapted for quick charging 

NiMH cells 

First connect the charger cable's banana plugs to 

the charger and only then connect the cable's other 

end into the charging jack on the transmitter. Never 

allow the bare ends of the banana plugs to come 

into contact with one another when the other end of 

the cable is plugged into the transmitter. In order to 

prevent damage to the transmitter, charging current 

should never exceed 1 A. If necessary, limit the 

current at the charger.

Removing the transmitter's battery

To remove the transmitter's battery, fi rst unlatch the 

cover of the battery compartment on the rear side of the 

transmitter housing then remove the cover.

Take out the transmitter's battery then disconnect the 

transmitter battery's connector by carefully pulling on the 

supply line cable. 

Inserting the transmitter's battery

Hold the transmitter battery connector 

such that the black or brown cable is 

oriented toward the antenna side and 

the empty jack of the battery connector 

is oriented toward the fl oor side then push the battery 

connector in the direction of the board onto the three pins 

sticking out out of the board inside the transmitter. (The 

battery connector is protected against a reverse polarity 

connection by two slanted edges, see illustration.) 

Place the battery into its compartment and close the 

cover.

Transmitter 

connector polarity
Operating notices 15

Battery operation timer at the bottom left of the 

screen

This timer shows the transmitter's cumulative operating 

time since the transmitter's battery was last charged. 

This timer is automatically reset to "0:00" when the 

transmitter is switched on and its battery voltage is 

signifi cantly higher than when the transmitter was last 

used, e. g. because the battery was charged.

GRAUBELE

#01

0:00h

Stop

Flt

«normal »

K78

0:00

0:00

0.0V

5.9V

Mx

HoTT

 Lithium battery, CR 2032

At the left side of the transmitter board there is a fi xture 

for a lithium battery. The user can replace this battery 

when necessary with another lithium battery of type 

CR 2032:

This battery maintains the date and time settings during 

a transmitter power supply outage, for example when 

the transmitter's main battery is being replaced.
16 Operating notices

 Receiver power supply

A selection of 4 and 5 cell NiMH battery packs having 

different capacities are available to power the receiver. If 

digital servos are in use, we recommend a 5 cell battery 

pack (6 V) to afford adequate battery capacity. If analog 

and digital servos are used in mixed operation, be sure 

to pay attention to the given maximum permissible 

operating voltage. A stabilized, adjustable power 

supply for the receiver with 1 or 2 receiver batteries 

can be provided, e. g. the PRX-unit, order no. 4136, see 

appendix.

For reasons of safety, do not use battery boxes or dry 

cell batteries.

The voltage of the on-board power supply will be 

displayed at the bottom right of the transmitter's screen 

while the model is in operation.

GRAUBELE

#01

2:22h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

If the adjustable warning threshold (default value 3.8 V) 

set in the Telemetry menu, see page 217, is underrun, 

an optical and acoustic under-voltage warning will be 

issued.

Despite this feature, be sure to check the condition 

of the battery at regular intervals. Do not wait for the 

warning to be issued before recharging the battery.

Notice:

An overview of available batteries, chargers and current 

source test instruments can be found in the Graupner 

RC main catalog or in Internet at www.graupner.de.

Charging the receiver battery

Charger cable, order no. 3021, can be plugged directly 

onto the receiver's battery for charging. If the battery in 

the model is connected by way of an order no. 3046, 

3934, 3934.1 or 3934.3 power supply cable, then 

charging can be accomplished via the charging jack or 

special charging connector integrated into the switch. 

The switch in the power supply cable must be in its 

"OFF" position for charging.

Receiver battery connection polarity

General charging notices

• The charging instructions for the charger as well as 

for the battery from its manufacturer to be observed.

• Pay attention to the maximum permissible charging 

current specifi ed by the battery's manufacturer. In 

order to prevent damage to the transmitter, charging 

current should never exceed 1 A. If necessary, limit 

the current at the charger.

• If the transmitter battery is nevertheless to be 

charged at a current rate in excess of 1 A, then 

it is imperative that this is done outside the 

transmitter. Otherwise there is a risk of damage to 

the transmitter's board due to overloading its printed 

circuit paths and/or overheating of the battery.

• If an automatic charger is to be used for charging, 

perform several test charging procedures to ensure 

the fl awless functionality of its automatic shut-off. 

This applies particularly if you want to charge the 

standard installed NiMH battery with an automatic 

charger unit intended for NiCd batteries Monitor the 

charger's shut-off behavior if it has that option.

• Do not execute a battery discharge or battery 

maintenance program through the charger jack. The 

charger jack is not suitable for this purpose.

• Alway connect the charger cable to the charger fi rst 

and then to the receiver or transmitter battery. This 

avoids the possibility of shorting the bare banana 

plug ends together.

• If the battery heats up signifi cantly, check the 

battery's condition, replace the battery or reduce the 

charging current.

• Never leave a charging battery unattended.

• Follow the safety notices and handling 

instructions provided on page 8.

Operating notices
Operating notices 17

 Joystick length adjustment 

The length of both joysticks can be continuously 

adjusted to adapt these transmitter controls to the pilot's 

preference.

Hold the lower half of the knurled grip in place then turn 

the upper section to release its counter-locked threads. 

Now pull up or push down on the joystick's end to the 

desired length. When the length is suitable, tighten the 

counter-locked threads of the upper and lower sections 

again.

 Opening the transmitter housing

Carefully read the notices below before opening the 

transmitter housing. It may be better if unexperienced 

users ask a Graupner Service location to take care of 

the procedures described below.

The transmitter should only be opened in the following 

situations:

• to convert a neutralized joystick to a non-neutralized 

joystick or a non-neutralized joystick to a neutralized 

joystick.

• to adjust joystick return tension.

Switch off the transmitter before opening its cover 

(power switch to "OFF"). 

Open the battery compartment as described on the 

previous double-page, remove the battery and if a micro 

SD card is inserted be sure to remove it too.

Once the battery and any micro SD card have been 

removed, loosen the six countersunk screws on the rear 

of the transmitter with a Phillips, size PH1, screwdriver, 

see illustration.

Housing screw locations

Hold the two housing sections together by hand then 

turn the transmitter upright over a suitable surface so 

these 6 screws can fall out without getting lost. Now lift 

up on the backplate carefully and turn it open to the right 

like you would open a book.

A T T E N T I O N:

Two multi-conductor cables connect the backplate 

with the transmitter electronics in the upper section. 

These connections must not be damaged.

Important notices:

• Make no modifi cations of any kind to the circuitry 

as this will void the guarantee as well as the 

unit's offi cial permit.

• Be sure not to touch the circuit boards with any 

metallic objects. Do not touch contacts with your 

fi ngers.

• Never switch the transmitter on when its housing 

is open.

When you close the transmitter again, be sure 

that ...

• ... no cables are caught between housing edges 

when the backplate is put into position.

• ... both housing parts are properly seated with one 

another before screwing them together. Never force 

the housing sections together.

• Turn the screws down into the existing housing 

threads without stripping them out.

• ... reconnect the battery.
18 Operating notices

Operating notices

 Converting joysticks

Neutralization

Both the left and the right joystick can be confi gured 

for neutralized or non-neutralized operation as desired. 

Open the transmitter housing as previously described.

To change the joystick's factory setting, locate the screw 

shown in the fi gure below enclosed in a white circle. 

Notice:

The aggregate for the right joystick is a mirror image of 

the left joystick so the corresponding screw for the right 

joystick is on the right side just below the middle.

Now turn this screw down until the respective joystick 

is free to move from limit to limit - or turn the screw out 

until the joystick again completely self-restoring. 

Do not touch the o not touch the 

circuit board! ircuit board!

Do not touch t Do not touch t

he circuit board! he circuit board!

user-replaceable 

CR2032 lithium battery to buffer the 

integrated realtime clock

Slot for

memory cards

Charger jack

left 

joystick aggregate oystick aggregate

brake springs

adjustment screws

brake springs

adjustment screws

collapsible antenna

neutralization screw

right 

joystick aggregate oystick aggregate

neutralization screw

adjustment screw for joystick restoration force
Operating notices 19

Joystick restoring force

The joystick's restoring force can also be adjusted to the 

pilot's preference. The adjustment is located next to the 

return springs, see markings in the fi gure below.

Spring force for the given direction of motion can be 

adjusted by turning the respective screw with a Phillips 

screwdriver.

• Right turn (clockwise) = return harder,

• Left turn (counter clockwise) = return softer.

horizontal orizontal

vertical ertical

Notice:

The aggregate for the right joystick is a mirror image of 

the left joystick so corresponding screws for the right 

joystick are located to the right of the middle.

Brake spring and ratchet

The outboard screw of the two marked in the next fi gure 

adjusts the braking force and the inboard screw adjusts 

the strength of the ratchet for the respective joystick. 

Notice:

The aggregate for the right joystick is a mirror image of 

the left joystick so corresponding screws for the right 

joystick are located at the top left.
20 Transmitter description

 Transmitter description

 Transmitter operating elements

Attaching the transmitter's neck strap

There is an eyelet on the top side of the mx-20 HoTT 

transmitter (see fi gure at the right) to which a neck strap 

can be attached. This anchor point has been chosen 

because the transmitter is optimally balanced here when 

it hangs from the strap. 

Order No. 1121 Neck strap, 20 mm wide

Order No. 70 Neck strap, 30 mm wide

Important notice:

 In its delivered confi guration, the transmitter can only 

operate any servos attached to the receiver by way 

of the two joysticks. For reasons of fl exibility, all other 

operating elements (CTRL 6 ... 8, SW 1 ... 9) are 

designated as "free" by the software. These other 

operating elements can be freely assigned to actuators 

as described in the text for the "Control adjust" menu 

on page 96 (winged aircraft models) or page 100 

(helicopter models). 

antenna with kink and twist joint

proportional speed control CTRL 7

3 position switch 

SW 4/5 or CTRL 9

2 position momentary 

contact switch SW 1

proportional speed 

control CTRL 6

left joystick

trimmer

ON/OFF switch

left touch pad

LC display

right touch pad

trimmer

right joystick

2 position switch SW 3

carrying handle

eyelet for neck strap

3 position switch 

SW 6/7 or CTRL 10

proportional speed control CTRL 8

2 position switch SW 2

2 position switch SW 8

2 position momentary 

contact switch SW 9

main status LED
Transmitter description 21

 Headset connector

The jack centered in the lower portion of the type 

plate on the back of the transmitter is for connecting 

conventional earplugs or a headset by way of a 3.5 mm 

audio plug. (not included in the set)

The transmitter's acoustic signals as well as those 

signals associated with the telemetry menu are output 

via this connection. These announcements are made in 

German language by default. More details about "Voice 

output" can be found in the section "HIDDEN MODE" 

beginning on page 28 and "Telemetry" beginning on 

page 208.

The headset connector's volume control can be adjusted 

in the "Voice volume" line of the "Basic Settings" menu, 

see page 227. 

 Mini-USB connector

This connector socket is used to establish a connection 

between the transmitter and a PC running a Windows 

operating system (XP, Vista or Windows 7). The PC 

software required, such as a suitable USB driver, can be 

found on the download page for the given product on the 

Graupner website at www.graupner.de. 

Once the necessary software is installed on the PC, this 

USB connection can be used to update the transmitter 

or even just to set the date and time in the transmitter. 

 Data jack

For connecting the optionally available Smart-Box, 

Order No. 33700. 

Details about the Smart-Box can be found with the given 

product in the Graupner RC main catalog or in Internet 

at www.graupner.de.

DSC jack for connecting 

fl ight simulators and for 

teacher/pupil mode

housing screw housing screw

housing screw housing screw

battery compartment cover

housing screw housing screw

Charger jack for 

transmitter battery 

Data jack for connecting 

the Smart-Box, Order 

No. 33700

fi ve-pole mini USB 

socket for connecting 

the transmitter to a PC

earplugs or 

headset connector

 Transmitter rear side
22 Transmitter description

Thus the transmitter is ready for operation. 

To the contrary, teacher mode for the mx-20 HoTT 

transmitter requires that the transmitter be switched 

on prior to plugging in the respective cable.

2. Connect the other end of the cable to the desired unit 

in compliance with the given operating instructions 

for that unit.

Important:

Be sure that all connectors are seated fi rmly in 

their respective sockets.

Notice about fl ight simulators:

Because of the myriad of fl ight simulators available on 

the market, it may be necessary to have the contact 

layout of the audio plug or DSC module appropriately 

modifi ed by Graupner Service. 

 DSC

Direct Servo Control

The acronym "DSC" is a carryover which stands for the 

original "Direct Servo Control" function. However, in 

HoTT systems the "direct servo control" function is no 

longer available via a diagnose cable due to technical 

reasons. 

The standard two-pole DSC jack in the mx-20 HoTT 

transmitter is used as the teacher or pupil jack as well 

as an interface to fl ight simulators.

To ensure a proper DSC connection, please observe:

Make any necessary menu changes.

Refer to the section beginning on page 198 to 

adapt the mx-20 HoTT transmitter to a teacher/pupil 

system.

1. When operating a fl ight simulator or when operating 

the mx-20 HoTT transmitter as a pupil transmitter, 

ALWAYS leave the transmitter's ON/OFF switch 

in the "OFF" position as only in this position does 

the transmitter's RF module remain inactive after 

the DSC cable is inserted. This also reduces the 

transmitter's power consumption somewhat.

The main status LED should now constantly 

illuminate red and the transmitter's basic setup 

screen should show the string "DSC pupil" on the 

right just below the middle timer. At the same time, 

the display of telemetry indicators will be suppressed.

PUPIL

#11

0:01h

Stop

Flt

DSC «normal »

0:00

0:00

5.9V

0.0V

HoTT

 Data storage

Card slot

micro SD and micro SDHC

With the mx-20 HoTT transmitter switched off, 

removing the battery compartment cover and the 

transmitter's battery will make the card slot accessible 

(located in the right sidewall of the battery compartment). 

This card slot is intended for micro SD and micro SDHC 

type memory cards.

All conventional micro SD memory cards up to 2 GB and 

micro SDHC cards up to 32 GB storage capacity can 

be used. However, as a manufacturer we recommend 

the use of memory cards no larger than 4 GB as this is 

completely adequate for all normal situations.

The type of memory card referred to here became 

known in conjunction with digital cameras and cell 

phones. It is to be pushed into the slot with its contacts 

upward, front facing the rear wall and latched in position 

there. After re-installing the battery and closing the 

battery compartment, the transmitter can be switched on 

again. The stylized image of a memory card will appear 

in the basic setup screen to indicate the presence of the 

inserted memory card.
Transmitter description 23

GRAUBELE

#01

3:33h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

Notice:

If a micro SD card is inserted, be sure to remove 

it BEFORE taking off the transmitter's backplate. 

Otherwise there is a risk of damaging the memory card.

 Data acquisition / storage

The storage of data on the SD card is coupled to the 

fl ight timer. If this timer is started – when a suitable 

memory card is inserted in the card slot and a telemetry 

link to the receiver exists – both the timer and data 

acquisition will stop when the fl ight timer is stopped. The 

fl ight timer is started and stopped as described in the 

section "Timers (general)" on page 138. 

While data acquisition is ongoing, the on-screen card 

image will blink continuously at a slow rate. 

The amount of data written on the memory card is 

presented as a black bar graph which grows from left to 

right as data fi lls the memory card.

After a data acquisition session is fi nished, there will 

be an (empty) folder "Models" and a "LogData" folder 

on the memory card. Within the "LogData" folder there 

will be log fi les in sub-folders that are designated with 

names in the format 0001_year-month-day.bin, 0002_

year-month-day.bin, etc. If a model memory folder is still 

"unnamed" when the memory card is removed from the 

transmitter and inserted into the card slot of a PC or 

laptop, the respective log fi les can be found in a subfolder designated "NoName". There is a PC program 

available on the transmitter's download web page at 

www.graupner.de with which the stored data can be 

evaluated on a compatible PC.

Importing voice fi les

As already mentioned in the section "Headsets" on 

page 21, this connection can also be used to output 

the transmitter's acoustic signals as well as those 

signals and announcements associated with telemetry 

menu settings. These announcements are made in 

German language by default. These announcements 

are summarized in a voice packet which is stored in a 

transmitter-internal memory but they can be replaced 

by a voice packet of a different language at any time. 

More information about this can be found in the section "HIDDEN MODE" beginning on page 28.

Importing/exporting model memories

Any model memory can be stored to an inserted memory 

card or from an inserted card into the transmitter. This 

feature is intended to support data exchange between 

identical transmitters or even use as data backup. 

More information about this can be found in the section "Copying/deleting" beginning on page 64. 

Notice:

Some special symbols that can be used in model names 

are subject to specifi c restrictions associated with the 

FAT or FAT32 fi le system used by the memory cards and 

these special symbols will be replaced during the copy 

process with a tilde (~).
24 Transmitter description - Display and keypad

 Display and keypad

Signal strength indicator

Battery time since last 

re-charge in h:min

Flight timer in min:s

(upward/downward)

Stopwatch in min:s

(upward/downward)

Flight phase name

switchover between 

fl ight phases by switch

Receiver power supply voltage

right touch pad: 

 

Paging / changing values

SET select / confi rm

Model name

Memory location 1 ... 24

Battery voltage and charge state bars

(if the preset threshold voltage is underrun, a warning will 

appear – see "Warnings" on page 36 –, and an acoustic 

warning tone will sound)

optical indication of trim lever positions or, during activation 

of speed controls CTRL 7 + 8, an alternative display of the 

current positions of these controls

Model type indicator

(winged aircraft / helicopter)

left touch pad

  paging

 simultaneously pressed: 

Change to the servo

display menu

ESC = cancel/return

ESC touched for about 1 s:

Change to the Telemetry menu 

and return to basic display

possible warnings, see page 36

simultaneous pressing of 

 or  = CLEAR
Transmitter description - Display and keypad 25

 Operating the "data terminal"

 Entry keys ESC and SET

 Display symbols

Displayed telemetry symbols

 the active model memory has not yet "bonded" 

with a HoTT receiver. More about the "Binding" 

process, see page 69 or 75.

 non-blinking: Switched off on RF transmitter side

blinking antenna symbol: 

The last receiver bound to the active model is 

inactive or out of range

>M x no telemetry signal to receive

>M signal strength indicator

>P indicator for pupil signal strength on the teacher 

transmitter display 

Keys left of the display

• key ESC

brief repeated pressing the ESC key will cause a 

stepwise return to the function selection screen or 

even further to the base screen. Any changes made 

to settings remain.

Momentarily touching the ESC key for about 1 s 

while in the base screen will open and close the 

Telemetry menu.

• arrow keys  

1. Momentarily pressing one of these keys will cause 

analogous paging in the given arrow direction 

through lists, e. g. through the model selection list 

or the multi-function list or within menus though 

the menu's lines. 

2. Simultaneous pressing on  will change the 

transmitter's base screen and almost any menu 

position to the "Servo display" menu.

Keys to the right of the display

• button SET

1. After switching the transmitter on, briefl y pressing 

the SET key will cause a jump from the displayed 

base screen to the Multi-function menu. In the 

same manner a selected menu can now be called 

up with the SET key. 

2. Momentarily pressing the SET key from within 

the Basic Settings menu will activate / deactivate 

(confi rm) the given setting fi elds.

• arrow keys  

1. "Paging" through the Multi-function menu and 

the menu lines within the Basic Settings menu 

analogous to the arrow keys of the left touch pad.

2. Select or set parameters in setting fi elds after they 

have been activated by briefl y touching the SET

key, whereby the  keys and  are used for 

the same corresponding functions. In this case it 

is completely irrelevant which of these two keys 

are used.

3. By briefl y pressing the  keys simultaneously 

or  an altered parameter value for the active 

entry fi eld will again be restored to its default 

value (CLEAR).

Notice:

• Touching the given touch pad does not itself initiate 

the given action but rather the end of the touch.

• In the event the touch pads do not exhibit any 

functionality immediately after switching the 

transmitter off and then on again right away, this is 

not a fault. Just switch the transmitter off again then 

wait for several seconds before switching it on again.
26 Transmitter description - Shortcuts

 Shortcuts

The following key combinations can be used to directly 

call up certain menus and options:

• CLEAR

Brief simultaneous activation of the  keys or

 on the right touch pad will restore the active 

entry fi eld's changed parameter value back to its 

default value.

• "Servo screen"

Brief simultaneous activation of the  keys of the 

left touch pad will cause a jump from the transmitter's 

base screen or from almost any menu position to the 

"Servo" menu, see page 230.

• "Telemetry" menu

Press the center ESC key in the left touch pad for 

about 1 s to call up the "Telemetry" menu from the 

transmitter's base screen, see text beginning on 

page 208, or to return to the base screen again.

• Graphic display of telemetry data

Briefl y touching one of the arrow keys of the left 

or right touch pad will cause a jump from the base 

screen directly to the transmitter's graphic display 

of telemetry data or will allow paging back and forth 

between individual graphic displays. 

Briefl y touching the centered ESC or SET key will 

cause a return back to the base screen.

• "HIDDEN MODE" 

(language selection and contrast)

Press and hold arrow keys  of the left touch 

pad then momentarily touch the SET key of the right 

touch pad, see next double-page.

• Entry lockout

Entry lockout is activated and deactivated from the 

base screen by simultaneously pressing the ESC

and SET keys for a little longer (about 2 s).

• Quick-Select

From the multi-function list, a jump can be made to a 

"Structure overview" by a brief, simultaneous touch 

on the  or  keys of the right touch pad. 

Menus are arranged in clear groups in this overview.

Memory

Servo settings

Transm. controls

Switches

Flight phases 

Timers

Mixers

Special funct.

Global functions

All menus

Now the desired group can be selected with the 

arrow keys of the left or right touch pad ... 

Memory

Servo settings

Transm. controls

Switches

Flight phases 

All menus

... and then briefl y touching the center SET key in 

the right touch pad. As soon as the key is released, 

only the respective generic term for the given menu 

will remain listed. For example:

Copy / Erase

Suppress menus 

Suppress models 

Model select
Transmitter description - Concealed menu columns 27

 Concealed menu columns

Some menus have concealed columns to improve 

legibility. Menus with concealed columns can be 

recognized by virtue of a triangle pointing to the right in 

the bottom left corner of the screen. For example, in the 

menu "Servo settings":

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

In this menu, e. g. the column "lim" +" (servo travel limit) 

to the right of column "- travel +" is "concealed".

To reach this column, use the pointing triangle at the 

bottom left of the screen to push the frame marker with 

the arrow key  of the left or right touch pad to just 

beyond the column for "- travel +":

S1

S2

S3

Rev cent lim +

0%

0%

0%

150% 150%

150% 150%

150% 150%

0%

0%

150% 150%

150% 150%

S4

S5

To again return to the now-concealed column "- travel 

+" or even further to the left, push the frame marker with 

arrow key  of the left or right touch pad appropriately 

to the left:

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

This procedure is analogous for the other menus.
28 Transmitter description - Hidden mode

The mx-20 HoTT transmitter's "HIDDEN MODE" can 

be reached from almost any menu position by pressing 

and holding the  arrow keys of the left touch pad 

and the SET key of the right touch pad for about one 

second until the screen shown below is displayed.

 HIDDEN MODE 

CONTRAST

LANGUAGE

0

DEUTSCH

VOICE DEUTSCH

STICK CALI.

 CONTRAST

The screen's contrast characteristic can be adapted as 

needed in this screen's "CONTRAST" line, as described 

in more detail on pages 226/226, by tapping on the 

center SET key of the right touch pad. Tapping again 

on the SET or ESC keys will cause a return to line 

selection.

The line ...

 LANGUAGE 

... can be reached by tapping arrow key  in the left 

or right touch pad. One of the transmitter's available 

languages can then be selected from the screen which 

appears.

HIDDEN MODE 

CONTRAST

LANGUAGE

0

DEUTSCH

VOICE DEUTSCH

STICK CALI.

Activate language selection by pressing on the center 

 HIDDEN MODE

Language selection and display contrast

SET key in the right touch pad.

HIDDEN MODE 

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

STICK CALI.

DEUTSCH

Now the default language "GERMAN" can be replaced 

with the desired language by making a selection with the 

arrow keys of the right touch pad. For example:

 HIDDEN MODE 

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

STICK CALI.

ENGLISH

Confi rm the selection by tapping again on the center 

SET key in the right touch pad. All settings stored in the 

transmitter remain intact after a change of language has 

been made.

The following languages are available for selection at 

the time this handbook was printed: 

• German

• English

• French

The Italian and Spanish languages are planned for 

inclusion at a later point in time. These will then be 

made available by way of an update download from the 

transmitter's web page at the Graupner website 

www.graupner.de.

 VOICE TRIGGER

As mentioned in section "Headsets" on page 21, the 

transmitter's acoustic signals as well as those signals 

and announcements associated with the telemetry 

menu can be output by way of the headset connector. 

These announcements are made in German language 

by default. These announcements are summarized in 

a voice packet which is stored in a transmitter-internal 

memory but they can be replaced by a voice packet of a 

different language at any time.

The following languages are available for selection at 

the time this handbook was printed: 

• German

• English

• French

The Italian and Spanish languages are planned for 

inclusion at a later point in time. These will then be made 

available on the transmitter's download web page at the 

Graupner website www.graupner.de.

The given active language packet can then be swapped 

out either with the PC program (also available as a 

download from the transmitter's web page at 

www.graupner.de) or per SD card as described below.

Preparation

If not already done, insert the SD card or SDHC card 

into the transmitter as described on page 22. Now 

when the transmitter is switched on it will perform 

some operations which will include the creation of a 

"VoiceFile" on the memory card. 

Take this memory card, which has now been prepared 

by the transmitter, out of the transmitter and insert it 

into a suitable card reader. If necessary, attach the card 

reader to your PC or laptop. Now copy the language 
Transmitter description - Hidden mode 29

packet downloaded from the transmitter's web page (e.g. 

"voice_gb.vdf") into the folder created by the transmitter. 

Now take the memory card out of the card reader and 

re-insert it into the transmitter. Once the memory card is 

inserted in the transmitter, switch the transmitter on with 

RF switched off.

RF on/off?

ON

Please select

OFF

Language change

Use the left or right arrow touch key to select the line 

"VOICE". 

 HIDDEN MODE 

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

STICK CALI.

ENGLISH

Activate language selection by pressing the center SET

key in the right touch pad.

 HIDDEN MODE 

CONTRAST

LANGUAGE

0

VOICE

STICK CALI.

ENGLISH

DEUTSCH

Now use the right touch pad arrow keys to replace the 

default language "DEUTSCH" with the language you 

want. For example:

 HIDDEN MODE 

CONTRAST

LANGUAGE

0

VOICE

STICK CALI.

ENGLISH

ENGLISH

Confi rm your selection with another tap on the center 

SET key in the right touch pad. The selected language 

packet will be loaded into the transmitter's memory.

 HIDDEN MODE 

CONTRAST

LANGUAGE

0

VOICE

STICK CALI.

ENGLISH

ENGLISH

22/100%

I

The loading process is fi nished as soon as the progress 

bar at the lower edge of the display disappears.

 HIDDEN MODE 

CONTRAST

LANGUAGE

0

VOICE

STICK CALI.

ENGLISH

ENGLISH

When this process is fi nished, switch off the transmitter. 

All settings stored in the transmitter remain intact after a 

change of language has been made.

Notice:

• If the warning ...

RF

MUST BE

OFF

OK

... appears, then the transmitter's RF radiation is still 

active. Jump to the "Basic settings" menu, select 

the "RF transmit" line, select its "OFF" option and 

then repeat the procedure

• If the warning ...

SD-CARD

INSERT

OK

... appears then the transmitter does not detect a memory 

card in its card slot or the card found cannot be read.

• If the warning ...

MISSING

IMPORT

DATA

OK

... appears then the transmitter could not fi nd an 

appropriate fi le on the inserted memory card.

 JOYSTICK CALIBRATION

If you feel the neutral position of your self-calibrating 

joysticks (controls 1 ... 4) are not exactly 0 % of 

their control travel, then this can be checked and, if 

necessary, corrected as follows.

Jump to the "Model select" menu and initialize a free 

model memory as described on page 60. Whether the 

model to be initialized is a winged aircraft or a helicopter 

is irrelevant. 
30 Transmitter description - Hidden mode

Wait for the notices which typically appear in the base 

screen following a model change then jump to the 

"Servo display" menu, for example by simultaneously 

touching the  keys of the left touch pad (WITHOUT 

any interim change to trim settings or other program 

settings). 

If all four of your transmitter's joystick functions are still 

self-neutralizing, this display should ideally look like the 

one shown below.

1

3

5

7

+

0%

0%

9

11

0%

0%

2

4

6

8

+

0%

0%

0%

10 0%

12 0%

–100%

0%

0%

Otherwise the graph bars show current setting 

percentages for joystick control functions which are not 

self-neutralizing – typically for the "K1", throttle/brake or 

throttle/pitch, control stick. For example, if the throttle/

brake control stick is in its "quarter-throttle" position, the 

display would appear as shown below.

1

3

5

7

+

0%

0%

9

11

0%

0%

2

4

6

8

+

0%

0%

0%

10 0%

12 0%

–50%

0%

0%

One after the other, put both joysticks into each of their 

four possible limit positions without exerting force at 

the limit position. In each of these eight possible limit 

positions, the – side dependent – indication for exactly 

-100 % or +100 % should be displayed. For example, 

if Control 2 is at its left limit and the other three joystick 

functions are in their respective middle positions then 

your transmitter's display should look like the one shown 

below.

1

3

5

7

+

0%

0%

9

11

0%

0%

2

4

6

8

+

–100%

0%

0%

10 0%

12 0%

0%

0%

0%

Regardless of the number of self-neutralizing joystick 

functions available on your transmitter, if these checks 

produce four 0 % results and eight 100 % results then 

your transmitter's joysticks are optimally calibrated. You 

can terminate this process then, if appropriate, delete 

the model memory just created.

Otherwise jump (as described at the outset of the 

previous double page) to the "Stick cali." line in the 

"HIDDEN MODE" menu then briefl y touch the center 

SET key in the right touch pad.

STICK CALIBRATION

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

ENGLISH

STICK CALI.

0%





The arrow keys  of the right touch pad will now 

allow you to cyclically select the four calibrated joystick 

planes, e.g. the left/right plane of the right joystick.

STICK CALIBRATION

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

ENGLISH

STICK CALI.

0%





Now position the right joystick – without exerting extra 

force – to its left limit corresponding with the on-screen 

blinking arrow pointing to the left.

STICK CALIBRATION

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

ENGLISH

STICK CALI.

+100%





... and briefl y touch the center SET key in the right 

touch pad. This concludes this example calibration of the 

right joystick's left limit. The circle in the middle of the 

stylized joystick plane will now blink as confi rmation of 

the calibration.

STICK CALIBRATION

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

ENGLISH

STICK CALI.

+100%





Now release the self-neutralizing joystick so it can return 

to its center position and then tap again on the center 

SET key to calibrate the joystick's centered position. The 

right arrow marker will begin to blink.
Transmitter description - Hidden mode 31

STICK CALIBRATION

CONTRAST

LANGUAGE

0

VOICE DEUTSCH

ENGLISH

STICK CALI.

0%





Repeat the calibration process for the right limit of the 

right joystick. The other joystick planes are calibrated 

analogously.

Notice:

• Correct any bad calibrations by repeating the 

respective process.

• Within a given joystick plane, each of the three 

calibration positions can be selected directly with the 

 arrow keys of the left or right touch pad.

Briefl y touching the center ESC key of the left touch pad 

will terminate the process and return to the sub-menu 

"Stick cali.".
32 Transmitter description - Telemetry data display

As described on page 220 in the context of sub-menu 

"SENSOR SELECT" for the "Telemetry" menu ...

Model select

Base setup model

Model type

Copy / Erase

Suppress models

Suppress: TOG

... the output of sensors attached to the receiver can be 

processed and activated for graphic presentation on the 

screen. This data is then appropriately displayed by the 

graphic indicators described below. 

These graphic elements can be reached from the 

transmitter's base screen by briefl y touching the  or 

keys of the left or right touch pad. Page back and forth 

between individual graphic elements with the same keys 

and return to the base screen again with the ESC key. 

Notice:

The sequence of the following element descriptions 

corresponds to their selection sequence when touching 

the  key.

More details about the following named modules can be 

found in the appendix and in Internet at www.graupner.

de in the web page for the given product.

RECEIVER

RX–S QUA: 100%

RX–S STR: 100%

TX–dBm: 33dBm

RX–dBm: 33dBm

RX–VOLT:4.8 TMP

L–PACK: 10ms

CH OUTPUT TYPE:ONCE R–LOW V:4.6 +22°C

This screen presents the "RX DATAVIEW" of the 

Telemetry menu's "SETTING & DATA VIEW", see page 

209, with data processed and displayed graphically. 

The displayed items are as follows:

Value Explanation

RX-S QUA signal quality in %

RX-S ST signal strength in %

RX-dBm reception power in dBm

TX-dBm transmit power in dBm

V PACK Indicates the longest time span in ms 

in which data packages are lost in the 

transmission from the transmitter to the 

receiver.

RX-VOLT current operating voltage of the 

receiver's power supply in volts

M-RX V lowest receiver operating voltage since 

last startup, in volts

TMP the thermometer depicts the receiver's 

current operating temperature

AKKU 1 (GENERAL + ELECTRIC modules)

0.0V

0.0A

0mAh

This display depicts current voltage, current current 

draw and, if attached, the expended capacity of "Batt 1" 

connected to the General-Engine (Order No. 33610), 

General-Air (Order No. 33611) or Electric-Air module 

(Order No. 33620).

SENSOR 1 (GENERAL + ELECTRIC module)

0.0V

0°C

SENSOR 1

If attached, this display depicts currenly measured voltage 

and temperature from a "T(EMP)1" temperature/voltage 

sensor, Order No. 33612 or 33613 for General-Engine 

(Order No. 33610), General-Air (Order No. 33611) or 

Electric-Air module (Order No. 33620).

 Telemetry data display
Transmitter description - Telemetry data display 33

SENSOR 2 (GENERAL + ELECTRIC modules)

0.0V

0°C

SENSOR 2

If attached, this display depicts currently measured 

voltage and temperature from a "T(EMP)2" temperature/

voltage sensor, Order No. 33612 or 33613 for GeneralEngine (Order No. 33610), General-Air (Order No. 33611) 

or Electric-Air module (Order No. 33620).

Rotary speed sensor

U/min

0

0 0

If attached, this display depicts the speed measured 

by a speed sensor, Order No. 33615 or 33616, for a 

General-Engine (Order No. 33610), General-Air (Order 

No. 33611) or Electric-Air module (Order No. 33620).

Notice:

The appropriate blade count must fi rst be set in the 

module's telemetry menu before the correct speed can 

be displayed.

Vario

0.0

0m

m

s

If attached, this display will depict altitude relative to 

location or starting location (in m) as well as the current 

ascent/decent rate (in m/s) from data provided by a 

GPS-/Vario module (Order No. 33600) or Vario module 

(Order No. 33601) connected to the receiver's telemetry 

connection.

GPS

N

W E

S

Kmh

0

km/h

DIS 

m 

m/s 

ALT 

m 

0

0

0.0

0

If attached to the receiver, this display will depict the 

data from a GPS module with integrated Vario, Order 

No. 33600. 

The displayed items are as follows:

Value Explanation

km/h Speed 

DIS horizontal distance in m

m/s ascent/decent rate in m/s

ALT altitude relative to starting location in m

GPS

N RXSQ 0 

DIS 0m

ALT 0m

0.0m/1s 

0m/3s 

0m/10s

N 0°00.0000

E 0°00.0000

W E

S

Kmh

0

If attached to the receiver, this display will depict the 

data from a GPS module with integrated Vario, Order 

No. 33600. 

Aside from the model's current position and speed, the 

center section of this screen will also display current 

altitude with respect to the starting location as well as 

the model's current ascent/decent rate in m/1 s, m/3 s 

and m/10 s, current reception quality and the model's 

distance from its starting location.

The displayed items are as follows:

Value Explanation

W / N / E / S west / north / east / south

Kmh speed

RXSQ return channel signal strength

DIS distance

ALT current altitude with respect to starting

m/1 s m/1 s ascent/decent rate

m/3 s m/3 s ascent/decent rate

m/10 s m/10 s ascent/decent rate
34 Transmitter description - Telemetry data display

VARIO

RXSQ

 0

 MAX

 0m

 MIN

 0m

ALT

 0

H

L

m/1s

0.0

m/3s

0.0

m/10s

0.0

If attached to the receiver, this screen will display the 

data acquired by a Vario module, Order No. 33601. 

The displayed items are as follows:

Value Explanation

ALT current altitude

RXSQ Signal strength of the signal received 

by the receiver in %, see page 209.

MAX the preset maximum altitude limit 

relative to starting location at which, 

when exceeded, will cause an audible 

warning to be sounded

MIN the preset minimum altitude limit 

relative to the starting location at 

which, when underrun, will cause an 

audible warning to be sounded

m/1 s m/1 s ascent/decent rate

m/3 s m/3 s ascent/decent rate

m/10 s m/10 s ascent/decent rate

ELECTRIC AIR MODULE

0.0V 0m/3s

BAT1 0m/1s

BAT2

0.0V T2 0°C

T1 0°C

0

1L0.00

2L0.00

3L0.00

4L0.00

5L0.00

6L0.00

 ALT 0m

7L0.00

 0.0V 0A

0.0V 0m/3s

BAT1 0m/1s

BAT2

0.0V T2 0°C

T1 0°C

0

1H0.00

2H0.00

3H0.00

4H0.00

5H0.00

6H0.00

 ALT 0m

7H0.00

 0.0V 0A

If attached to the receiver, this screen will display 

the data acquired by an Electric-Air module, Order 

No. 33620. More details about this module can be found 

in the appendix or in Internet at www.graupner.de in the 

web page for the given product.

Depending on how this module is equipped with 

sensors, this screen can permanently display the data 

shown in the adjacent table.

The current voltage of up to two batteries (BAT1 and 

BAT2), up to two temperature measurements (T1 and 

T2), current altitude with respect to the starting location, 

the model's ascent/decent rate in m/1 s and m/3 s and, 

in the middle of the screen, the current draw currently 

being taken from a power source.

Along the right edge of the screen is a table of 

alternating values for cell voltages at balancer 

connections (L) or voltages for up to 7 attached battery 

cell packs (H). 

The displayed items are as follows:

Value Explanation

V current voltage

A current current

BAT1 / BAT2 battery 1 or 2

ALT current altitude

m/1 s m/1 s ascent/decent rate

m/3 s m/3 s ascent/decent rate

T1 / T2 temperature of sensor 1 or 2

L or H cell voltage of cells 1 ... 14 (14 max)

L = balancer connection 1

H = balancer connection 2

GENERAL MODULE

0.0V

BAT1

BAT2

0.0V T2 0°C

 T1 0°C

E FUEL F

CELL V

1:0.00

2:0.00

3:0.00

4:0.00

5:0.00

6:0.00

0

0.0V

BAT1

BAT2

0.0V T2 0°C

 T1 0°C

E FUEL F

 ALT 

0m

 0m1

 0m3

 0.0A

POWER 

 0.0V

0

If attached to the receiver, this screen will display the 

data acquired by a General-Engine module, Order 

No. 33601, or a General-Air module, Order No. 33611. 

More details about these modules can be found in the 
Transmitter description - Telemetry data display 35

appendix or in Internet at www.graupner.de in the web 

page for the given product.

Depending on how this module is equipped with 

sensors, this screen can permanently display the data 

shown in the table below.

The current voltage of up to two batteries (BAT1 

and BAT2), the measurement results of up to two 

temperature sensors (T1 and T2) and a fi ll level gage for 

the fuel tank.

An alternating display along the screen's right edge will 

display a list of current cell voltages for a LiPo battery 

with up to six cells or operational data (current altitude 

with respect to the starting location, ascent/decent m/1 s 

and m/3 s, current current being drawn in amperes and 

current voltage of the battery connected to the sensor). 

The displayed items are as follows:

Value Explanation

BAT1 / BAT2 battery 1 or 2

FUEL fuel level / tank gage

E / F empty / full

T1 / T2 temperature of sensor 1 or 2

CELL V voltage of cells 1 ... 6 (6 max)

ALT current altitude

0m1 m/1 s ascent/decent rate

0m3 m/3 s ascent/decent rate

A current draw i amperes

V battery voltage
36 Transmitter description - Warning notices

Warning notices

BIND N/A

OK

"Bind not available"

A receiver has not yet been 

bound to the currently active 

model memory. Briefl y touching 

the SET key will cause a direct 

jump to the appropriate option.

RF on/off?

ON OFF

Please select Please select RF transmission 

"ON" or "OFF".

battery

needs

charging Operating voltage is too low

Fail Safe

setup

t.b.d.

Failsafe has not yet been 

activated

MISSING

IMPORT

DATA

OK

A suitable language fi le 

cannot be found on the 

memory card

Throttle

too

high !

Helicopter throttle joystick or 

limiter too high

RF

MUST BE

OFF

OK

Prompt to switch off RF 

transmission

(language fi le can only be 

loaded when RF is switched off)

 Warning notices

CAN‘T

RECEIVE

DATA

OK

No bound receiver in range

No

pupil

signal

Connection between teacher 

and pupil is interrupted

SD-CARD

INSERT

OK

No SD or SDHC memory card 

in the card slot or card is not 

legible

• Is the "wireless teacher/pupil connection" that was 

active when the transmitter was last used to be 

continued, CONT or switched off OFF?

TRAINER

Wireless Link

ACT INH

• After being switched on, the transmitter has not 

been used within the time limit preset in the "Poweron beep" line of the "Basic Settings" menu, see 

page 227. The message ...

Power on waning

is active!

... will appear in the screen, the center LED will 

alternately blink red and blue and an acoustic 

warning tone will sound.

If the transmitter continues unused it will 

autonomously switch itself off after one minute.

• When battery voltage is too low, a model change is 

blocked for reasons of safety. The screen will show 

an appropriate message.

not possible now

voltage too low
Transmitter description - Function fi elds, position indicator and entry lockout 37

As soon as one of the proportional controls (CTRL 7 & 8) 

in the middle console is turned, a small symbol will appear 

to the left of the two vertical position indicators. 

At the same time, for the duration of the control's 

operation, the position indicator for the two vertical bars 

in the middle will change from displaying current trim 

position to a display of the respective current position of 

the proportional controls CTRL 7 & 8.

Logically, the left proportional control (CTRL 7) is 

displayed by the left bar indicator and the right bar 

indicator displays the position of the right proportional 

control (CTRL 8). The two horizontal bars continue to 

show current trim positions of respective joystick trim 

controls.

GRAUBELE

#01

3:33h

Stop

Flt

K78

0:00

0:00

RX0.0V

5.2V

M

HoTT

About 2 seconds after operating one of the proportional 

controls has ended, the display will again revert to 

display of current trim positions of the four trim controls 

generated by the two joysticks.

 Position indicator

Proportional controls, CTRL 7 and 8

The touch keys can be locked out to prevent unintended 

access and operation of settings. This lockout is 

established (when the mx-20 HoTT transmitter is 

displaying its base screen) by simultaneously pressing 

and holding both the ESC and SET keys for about two 

seconds. This lockout condition is indicated by a key 

symbol, located at the intersection point of the trim bars, 

which is displayed in reverse video. 

GRAUBELE

#01

3:33h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

The lockout is effective immediately but controls remains 

operationally ready. 

The lockout can be removed by again touching and 

holding the ESC and SET keys for about two seconds. 

A lockout condition is also removed the next time the 

transmitter is switched on.

 Function fi elds in the display

SEL, STO, SYM, ASY, , 

 Entry lockout

Depending on the given menu, certain function fi elds will 

appear on the bottom display line.

CLR SEL STO SYM ASY

A marked function is activated by tapping on the SET

key.

Function fi elds

• (clear) delete CLR

• SEL (select): selection

• STO (store): store (e. g. control position)

• SYM set values symmetrically 

• ASY set values asymmetrically 

• switch symbol fi eld

 (assignment of all types of switches)

• within a menu, change to the 

second page (menu continuation)
38 Putting the transmitter into operation

Preliminary remarks

Graupner's HoTT system theoretically permits 

simultaneous operation of more than 200 models. 

However, because of the interspersed radio-frequency 

utilization permitted by certifi cation for the 2.4 GHz 

ISM band, this number is signifi cantly lower in practical 

application. Nevertheless, in general more models 

can be operated simultaneously in the 2.4 GHz band 

than would be the case in conventional 35 or 40 MHz 

frequency bands. The real limiting factor is – as often 

before – is still likely to be the size of available 

operating space (i.e. airspace for aircraft). Alone the fact 

that it is no longer necessary to coordinate transmitting 

frequencies with other pilots in the vicinity (which is 

sometimes quite diffi cult in broken landscapes, such as 

on hillside slopes) represents an enormous boost for 

remote control operating security.

Battery charged?

Since the transmitter is delivered with an empty (not 

charged) battery, the battery must fi rst be charged 

according to the charging instructions on page 14. 

Otherwise a warning tone will be sounded when the 

low voltage threshold, preset in the "Batterie warning" 

line of the "Basic Settings", 

is underrun. This low voltage 

threshold can be set, as 

described on page 226. When 

this threshold is underrun, 

a warning tone will be sounded and an appropriate 

message will be overlaid on the base screen. 

Transmitter startup

After being switched on, the message shown below will 

appear in the transmitter's screen for about two seconds. 

RF on/off?

ON OFF

Please select

Within this brief period you may be able to switch off RF 

transmission by using the  or  key of the right touch 

pad to shift the query's response from "ON" to "OFF" 

such that the ON option is displayed in normal video and 

the OFF option is highlighted in reverse video.

RF on/off?

ON

Please select

OFF

Now switch the RF module off by tapping on the center 

SET key in the right key pad. 

The center LED, which in the meantime has been 

illuminating in blue, will change its color to red again and 

the transmitter's display will show the screen depicted 

below.

GRAUBELE

#01

0:33h

Stop

Flt

K78

0:00

0:00

0.0V

5.2V

M

HoTT

The symbol combination means that the currently 

active model memory has already "bonded" with a 

Graupner HoTT receiver in the past but there is no 

connection to this receiver at the moment. (In this 

example, RF transmission has been switched off.) 

If the transmitter were to be switched on without

switching off RF transmission, the center LED would 

illuminate in blue and the symbolic transmitter antenna 

battery

needs

charging

 Putting the transmitter into operation

Preliminary remarks about the mx-20 HoTT transmitter

in the screen would blink. At the same time, an acoustic 

warning will sound until a connection is established with 

the respective receiver. As soon as this connection is 

established, the "x" at the base of the antenna symbol 

will be replaced by a fi eld strength indicator, for example 

, and the optical and acoustic warnings will stop. 

If a telemetry connection has also been established for 

the incoming signal, that is output by the receiver in the 

model, then the right side of this same screen line will 

display a similar indication of signal strength for this 

reception of the receiver's transmitted signal (>M ) as 

well as the current voltage of the receiver's power supply. 

On the other hand, if the screen displays the symbol 

combination and the center LED illuminates in red 

continuously then the currently active model memory is 

not "bonded" to any receiver.

Under-voltage warning

If transmitter voltage drops below the adjustable 

threshold specifi ed in the "General Settings" menu, 

see page 226 (default value, 4.7 V), an optical and an 

acoustic under-voltage warning will be issued.

Important notices:

• The transmitter in the set is already preset, as 

delivered, with default values which are correct 

for operation in most European countries (except 

France). 

If the remote control system is to be operated in 

France then the transmitter MUST be changed over 

to "FRANCE" mode, see page 227. IN NO CASE may 

the Universal/EUROPE mode be used IN FRANCE.

• The receiver included in the set with the mx-20

HoTT 2.4 transmitter (and already bound to the 

transmitter by settings made in the factory) is 
Putting the transmitter into operation 39

capable of operating up to 12 servos.

In order to achieve the greatest possible 

fl exibility but still preclude unnecessary 

inadvertent operator errors, control channels 5 ... 

12 have not been assigned to any controls. This 

means that servos connected by way of these 

channels will remain in their middle positions 

until an operator element has been assigned. 

Practically all mixers are initially inactive for 

this same reason. More about this can be found 

on page 96 (winged aircraft) or 100 (helicopter 

models).

• The fundamental procedure for initial 

programming of a new model memory location 

can be found on page 60 and the programming 

examples that begin on page 236. 

• When the remote control system is switched on, 

being bonded or when making settings, that the 

transmitter's antenna is always far enough away 

from the receiver's antennas. If the transmitter's 

antenna is brought too close to the receiver's 

antennas this will cause receiver over-modulation 

and its red LED will illuminate. At the same 

time the return channel will drop out and, as a 

consequence, the fi eld strength indicator in the 

transmitter's screen will be replaced by an "x" and 

the receiver's current battery voltage display will 

show 0.0 V. The remote control is then in Fail-Save 

mode, see page 196, i. e. when signal reception 

drops out all servos will remain in their current 

positions until a valid signal is again received.

In such a case, increase the distance (between 

the transmitter and the model containing the 

receiver) until the indicators are again "normal".

Transmitter fi rmware updates are made at one's own 

risk by connecting the fi ve-pole mini-USB connector on 

the rear side of the transmitter to a PC running Windows 

XP, Vista or Windows 7. 

Current software and information is available in Internet 

at www.graupner.de under the download link for the 

given product. 

Notice:

You will automatically be notifi ed of new updates per 

email after registering your transmitter at 

https://www.graupner.de/de/service/produktregistrierung. 

The USB cable delivered with the USB interface option, 

Order No.7168.6, is also needed to make an update. 

This cable's connector is plugged directly into the 5-pole 

mini-USB connector socket on the rear side of the 

transmitter

Updating mx-20 HoTT software

Notice:

Be sure to check the charge status of your 

transmitter's battery or charge its battery as a 

precaution before every update. Also backup all 

occupied model memories so they can be restored if 

that should become necessary. 

1. Installing drivers

Install the required driver software, included in the 

"USB Drivers" folder of the program packet, onto 

your PC or laptop so your computer can handle the 

transmitter's integrated USB interface.

Start driver installation with a double-click on the 

respective fi le and follow the on-screen instructions. 

Once this software has been successfully installed, 

the computer must be re-started. Drivers only need 

to be installed once.

2. Installing the software up-loader

Unpack fi le "Radio_grStudio_Install_VerXX.zip" 

and start the actual installation program "Radio_

grStudio_Install_VerXX.msi" with a double-click then 

follow the instructions. 

This program is installed by default under "Start\

Programs\Graupner\ Radio_grStudio\Radio_

grStudio_Ver-SX.X".

3. Establishing a transmitter-to-PC connection

With the transmitter switched off, connect the USB 

cable by way of its 5-pole mini-USB socket to the rear 

side of the transmitter.

4. Updating mx-20 HoTT transmitter software

Start the "Radio_grStudio_Ver-SX.X" program from 

the respective folder, by default at "Start\Programs\

Graupner\ Radio_grStudio\Radio_grStudio_VerSX.X".

Use the selection sequence "Menu", "Port Setup" or 

open the "Controller Menu" and click on "Port select".

 Transmitter fi rmware updates
40 Putting the transmitter into operation

Now in the "Port select" window, select the COM 

port connected to the USB interface. The correct port 

can be recognized by its designation "Silicon Labs 

CP210x USB to UART Bridge" in the "Device Name" 

column. In the above example this would be the 

"COM 3" port.

Now call up menu option "Firmware Upgrade" from 

"Menu" or open the "Controller Menu" and click on 

"Firmware Upgrade".

Click on the button labeled "File Browse" and select 

the desired fi rmware update fi le with a ".bin" fi lename 

extension from the "Open fi le" window.

Firmware fi les are product-specifi cally coded, i. e. if 

you should accidentally select a fi le which does not 

correspond to the product (e. g. receiver update fi le 

instead of a transmitter update fi le), the "Product 

code error" popup window will appear and the block 

the update process from starting.

Now switch on the transmitter then start the 

transmitter update by clicking on the "Download 

Start" button. 

After a brief period a warning will appear stating 

that the transmitter's RF transmission will now be 

interrupted and that, because of this, any receiver 

system currently in operation should be switched off. 

Switch off your receiver system if it is switched on 

then click on "Yes".

This will start the actual update process. A progress 

bar will begin to operate above a sequence of 

running text lines.

Do not terminate the update process before the 

progress bar has reached its right end and the 

"Firmware Download Success" message appears.

Click on "OK". Subsequently switch off the transmitter 

and disconnect the USB cable between the 

transmitter and the PC or Laptop.

If the progress bar hangs up without showing any 

further progress, close the program and repeat 

the update process. Be sure to watch for any error 

messages that may appear.
Your notes 41
42 Putting the transmitter into operation

 Receiver initialization

Preliminary remarks about the GR-24 receiver

Receiver system

The mx-20 HoTT remote control set includes a type 

GR-24, 2.4 GHz bidirectional receiver for connecting up 

to 12 servos.

After switching on this HoTT receiver, should "its" 

transmitter not be within range or switched off, then the 

receiver's red LED will illuminate continuously for about 

1 s then begin to blink slowly. This indicates the receiver 

has not (yet) established a link to a Graupner HoTT 

transmitter. If a link has been established, the green 

LED will illuminate continuously and the red LED will 

extinguish. 

In order to establish a link to the transmitter, the 

Graupner HoTT receiver must fi rst be "bound" to 

"its" particular model memory in "its" Graupner HoTT 

transmitter. This procedure is known as "binding". 

This "binding" linkage is only necessary once for each 

receiver/model memory combination. Refer to pages 

69 or 74. The "binding" procedure has been done at 

the factory for model memory 1 of the units delivered 

together as a set so this "binding" procedure will only 

be necessary to link additional receivers or if a memory 

location change becomes necessary (and – e. g. after a 

change of transmitter – can be repeated anytime).

On-board voltage display

The current voltage of the receiver's power supply will 

be shown in the right side of the transmitter's screen 

if a telemetry link exists between the receiver and 

transmitter. 

Temperature warning

Should the receiver's temperature sink below an 

adjustable threshold (default value -10 °C) or rise 

above an adjustable threshold (default value +55 °C), 

an acoustic warning will be issued by the transmitter in 

the form of a uniform beep of about 1 s duration. The 

aforementioned threshold limits are stored and adjusted 

in the receiver.

Servo connections and polarity

Graupner HoTT receiver servo connections are 

numbered. The connectors used are keyed against 

polarity reversal. Pay attention to the small side profi les 

when plugging in these connectors. Never use force. 

The two outer connections, having designations "11+B-" 

and "12+B-" are intended for the battery connections. 

These two connections plus the servo's respective 

connections can be combined into a single connector at 

each end by way of a V or Y cable, Order No. 3936.11.

Do not reverse the polarity of this connection. 

Reversed polarity could destroy the receiver and 

devices attached to it.

The supply voltage is bussed across (i.e. common 

for) all numbered connections. The function of every 

individual channel is determined by the transmitter 

used, not by the receiver. It is not only the throttle servo 

connection which is different for every manufacturer and 

model type. For example, in Graupner remote control 

systems the throttle servo is on channel 1 for winged 

aircraft and on channel 6 for helicopter models. 

Concluding notices:

• The signifi cantly greater servo resolution 

characteristic of the HoTT system produces a 

noticeably fi rmer response behavior in comparison 

to previous technology. Please take the time to 

familiarize yourself with this sensitive behavior.

• If you have a speed controller with integrated BEC* 

arranged in parallel with the receiver battery, its 

positive pole (red cable) may to be removed from the 

3-pole connector. Be sure to look for notices about 

this in the instructions for the speed controller used.

Use a small screwdriver to carefully lift the 

connector's middle latch slightly (1), 

pull on the red wire to remove its connector pin 

from the connector (2) 

then put insulation tape 

around the removed connector pin to prevent possible short circuit conditions (3).

red

1

2 3

Follow the installation instructions on page 46 for the 

receiver, the receiver antenna and for mounting the 

servo.

Reset

To execute a reset of the receiver, press and hold the 

SET button on the receiver's top-side while switching the 

power supply on. Once power is on, release the button 

again. 

If a receiver reset is done while the transmitter is 

switched off or on a receiver which is not bound, the 

receiver's LED will slowly blink red for about 2 or 

3 seconds and then a binding procedure can be started 

right away on the transmitter. 

If reset is done on a bound receiver and the 

corresponding model memory is active in the powered 

on transmitter, the LED will illuminate in green after 

a brief period as an indication that your transmitter/

receiver system is again ready for operation.

* Battery Elimination Circuit
Putting the transmitter into operation 43

Please note the following: 

A receiver RESET will cause ALL receiver settings 

- except for binding information - to return to their 

factory settings. 

Therefore if a RESET is triggered unintentionally, 

any custom settings that had been present in the 

receiver before the reset will have to be established 

again by way of the Telemetry menu.

A deliberate RESET is recommended, especially if 

a receiver is to be "transferred" into another model. 

This is a rather simple method to eliminate settings 

which are no longer applicable.

Receiver fi rmware updates are made by way of the 

connector located on the side of the receiver and 

the help of a PC running under Windows XP, Vista or 

Windows 7. The optional USB interface cable needed 

for this is Order No. 7168.6 along with adapter cable, 

Order No. 7168.6A. The programs and fi les also needed 

can be found in Internet on the Graupner website at 

www.graupner.de under the downloads for the particular 

product.

Notice:

After registering your receiver at https://www.graupner.

de/de/service/produktregistrierung, you will automatically 

receive notifi cation of future updates per email. 

Updating receiver fi rmware

Notice:

Before any update procedure, be sure to check the 

charged status of the receiver's battery. If necessary, 

charge the battery before beginning with an update.

1. Installing drivers

If not already done, install the required driver 

software for the USB interface, Order No. 7168.6, as 

described on page 39. 

2. Establishing a receiver / PC connection

Connect the USB interface cable, Order No. 7168.6, 

via the adapter cable, Order No. 7168.6A, with the 

"- + T" connector on the receiver. These connectors 

are protected against polarity reversal so pay 

attention to the small profi les on the sides of 

connectors. Do not use brute force, these connectors 

should latch in rather easily.

 Receiver fi rmware updates

Adapter lead

Order No. 7168.6A

If a central red wire is present, 

cut through it.

Attention: 

If the adapter cable is still has wires for all 

three poles, cut the red insulated wire for the 

middle connector pin of the adapter cable, Order 

No. 7168.6A.

Afterward, make the USB interface connection to the 

PC or laptop by way of the delivered USB interface 

cable (PC USB/mini-USB). If the USB interface is 

connect properly, a red LED on the interface board 

should illuminate for a few seconds.

If not already off, now switch the receiver off.

3. Firmware update utility program

On the PC, start the "Graupner_Firmware_Update_

Utility_VerX.XX.exe" program with a double-click. 

This program is located among the fi les in the 

"Firmware-Updater" folder. (At the time of printing for 

this manual, this program's current version is 1.18 

and it can be started without fi rst being installed.)
44 Putting the transmitter into operation

In the "COM Port Setup" group box, select the COM 

port to which the USB interface is connected. If you 

are not sure which selection is correct, press the 

"Search" control, choose the connection labeled 

"Silicon Labs CP210x USB to UART Bridge" from the 

popup window and then activate "OK". The "Baud 

Rate" setting should be "19200".

Afterwards, click on the "Signal 2:Vcc3:Gnd" radio 

button in the "Interface Type" group box.

Now click on the control labeled "Browse" that is 

located at the top right corner of the window. From 

the "Open fi le" window which appears, select the 

appropriate fi rmware update fi le for your receiver. 

Such fi les always have the ".bin" fi lename extension. 

Typically this fi le can be found in the folder whose 

name is prefi xed with the order number of the 

receiver to be updated. This folder should contain 

the ZIP fi le that was downloaded and unpacked. 

Its fi lename should also be prefi xed with the order 

number of the receiver to be updated. For the 

standard GR-12 receiver included in this set, the 

folder would be designated "33512_12CH_RX". The 

fi lename will appear in the corresponding window.

Firmware fi les are product-specifi cally coded, i. e. if 

you should accidentally select a fi le which does not 

correspond to the product (e. g. transmitter update 

fi le instead of a receiver update fi le), the "Product 

code error" popup window will appear and the block 

the update process from starting.

Activate the control labeled "Program". Wait for the 

progress bar to start. Depending on the speed of the 

computer being used, this may take several seconds. 

Now press and hold the receiver's SET button while 

switching on the receiver's power supply. After a few 

seconds the "Found target device ..." message will 

appear in the status display. Now you can release 

the receiver's button. The actual fi rmware update 

will begin autonomously after this message has 

appeared.

However, if the receiver is not detected, the "Target 

device ID not found" popup window will appear.

If this process terminates before reaching the 100 % 

mark, switch off your receiver's power supply then try 

to start the update process all over again. Do this by 

performing the above steps again.

The status display and progress bar will show you 

the progress of the fi rmware update. The update is 

concluded when the text "Complete ... 100 %" or 

"Complete!!" appears in the bottom line of the status 

display.
Putting the transmitter into operation 45

Both LEDs on the receiver will illuminate during the 

update process. Upon successful conclusion of the 

update process, the green LED will extinguish and 

the red LED will begin to blink.

Switch off the receiver, remove the interface cable 

and repeat the process for any other receivers you 

have which must be updated.

4. Receiver initialization

Following a successful update process you MUST 

perform a receiver initialization procedure before 

using the receiver again. This is necessary for 

reasons of safety.

Do this by pressing and holding the receiver's SET

button then switching the receiver's power supply 

on. Now release the SET button again. When you 

subsequently switch the receiver on again, the 

receiver's green LED will illuminate continuously for 

about 2 or 3 seconds. Except for binding information, 

all other settings that may have been programmed 

into the receiver will now be reset to factory defaults 

and will have to be re-entered again if they are 

needed.
46 Installation notices

Servo mounting lug

Retaining screw

Rubber grommet

Tubular brass spacer

4. Servo arms must be free to move throughout their 

entire range of motion. Pay attention that there are no 

objects which could hinder servo arm motion.

The sequence in which servos are connected to the 

receiver depends on the type of model. Follow the 

connection layouts provided for this on pages 57 and 59.

Also observe the safety notices provided on pages 4 ... 9.

In order to prevent uncontrolled movements of servos 

connected to the receiver during startup

always fi rst switch on the transmitter 

and then the receiver

and when fi nished with operation 

fi rst switch off the receiver 

and then the transmitter.

When programming the transmitter, be sure that 

electric motors cannot start running without control 

or that a combustion motor equipped with automatic 

starting cannot start up unintentionally. To be safe, 

disconnect the receiver's drive battery or, in the case of 

a combustion motor, disconnect the fuel supply.

The function of every individual channel is determined 

by the transmitter used, not by the receiver. However, 

channel assignments can be changed in the receiver 

by programming done in the "Telemetry" menu. 

Nevertheless, it is recommended this be done on the 

transmitter side via the "Transmitter output" option, see 

page 206.

Several notices and suggestions for installing 

remote control components into a model are 

provided below.

1. Wrap the receiver in a foam rubber pad that is at 

least 6 mm thick. Attach the foam rubber to the 

receiver with rubber bands so it will be protected 

against vibration and/or the jars of a hard landing. 

2. All switches must be installed such that they are not 

affected by exhaust gasses or vibration. The switch 

knob must be freely accessible over its entire range 

of movement.

3. Mount servos on rubber bushes/spacers with hollow 

brass bearings to protect them from vibration. Do 

not tighten the fastening screws down too tight as 

this would negate the vibration protection to be 

provided by the rubber bush/spacer. Only when servo 

fastening screws are properly tightened will this 

arrangement provide security and vibration protection 

for your servos. The fi gure below shows how a servo 

is mounted properly. The brass bearings are to be 

pushed into the rubber bushes/spacers from below.

 Installation notices

Receiver installation

Regardless of which Graupner receiver system you use, 

the procedure is always the same.

Please pay attention that the receiver's antennas must 

be mounted at least 5 cm away from all large metal 

parts or any wiring that is not directly routed out of 

the receiver itself. In addition to steel parts, this also 

includes carbon fi ber parts, servos, fuel pumps and all 

kinds of cables etc. Optimally the receiver should be 

placed at a readily accessible location that is well away 

from all other equipment. Under no circumstances may 

servo cables be wrapped around the antennas or routed 

close to it.

Please note that cables are subject to the acceleration 

forces which occur during fl ight and these forces may 

cause such cables, to shift in position. Therefore be 

sure the cables in the vicinity of the antennas are not 

able to move. Such moving cables can cause reception 

disturbances.

Tests have shown that vertical (upright) antennas 

provide the best results during wide-range fl ights. In the 

case of diversity antennas (two antennas), the second 

antenna should be oriented at a 90° angle to the fi rst 

antenna.

The GR-24 HoTT receiver connections designated 

"11+B" and "12+B" are intended for battery connections. 

If necessary, an addition battery connection for a 

servo can be made if a V or Y cable is used, Order 

No. 3936.11. The power supply is bussed across all 

numbered connections so it can be attached at any 

of these 12 connectors. However, due to additional 

voltage losses associated with the traverse connectors, 

connections 8, 9 and 10 should not be used for 

connecting the receiver's battery.
Installation notices 47

 Receiver system power supply

Among other aspects, the safe operation of a model 

depends on a reliable power supply. In the event that, 

despite smooth operating rods, fully charged battery, 

battery leads with adequate cross-section, minimum 

contact resistances at connectors, etc., the transmitter 

indicates repeated receiver voltage collapses or is 

receiver voltage is generally too low; please give 

attention to the following notices.

Give primary attention to fully charged batteries when 

model operation is to be started. Be sure that the 

contact surfaces of connectors and switches really are 

low resistance. If necessary, measure the voltage drop 

across installed switch cables when they are under 

load because even new heavy-duty switches can cause 

a voltage drop of up to 0.2 V. This value can increase 

in contacts by factors as a consequence of aging and 

oxidation. The constant vibrations and jarring also takes 

its toll on contacts to produce a creeping increase of 

contact resistance. 

Servos present another possible problem source. Even 

rather small servos like a Graupner/JR DS-281 can draw 

up to 0.75 A of current when it is blocks under load. Just 

four of these servos in a "foam" model can therefore load 

down the on-board power supply by as much as 3 A ...

Therefore you should choose a power supply which will 

not break down under greater loads but rather always 

deliver suffi cient voltage. To "calculate" necessary 

battery capacity you should always fi gure on at least 

350 mAh for every analog servo and at least 500 mAh 

for every digital servo. 

For example, from this point of view a battery with 

1400 mAh would be the absolute minimum to power 

a receiver system with a total of 4 analog servos. But 

be sure to also consider the receiver itself into the 

calculation because its bidirectional functionality will 

draw about 70 mA of current too.

It is also a good practice to connect the receiver to 

its power source with two cables rather than just one. 

Cable "1" could be connected to the "12+B" receiver 

connector as is usual and cable "2" could be connected 

to the opposite end of the row at the connector labeled 

"11+B". For example by using two power supply cables 

to connect one switch or voltage regulator to the 

receiver. Just use a V or Y cable, Order No. 3936.11

to accomplish this (see fi gure) if you should need one 

or both of the receiver's connectors to attach a servo, 

speed controller, etc. This double-connection technique 

to switches and speed controllers not only reduces the 

risk of a cable break but also ensures a more uniform 

supply of power to the connected servo.

Aux. function

Y-lead

Order No. 3936.11

PRX stabilised 

receiver power supply

Order No. 4136

NiMH 4-cell battery packs

In compliance with the aforementioned conditions, your 

Graupner HoTT receiver system can be readily operated 

with traditional 4-cell battery packs as long as the packs 

have adequate capacity and voltage level.

NiMH 5-cell battery packs

Five-cell battery packs offer a greater voltage tolerance 

than do 4-cell packs. 

However, be aware that not every servo available on 

the market is able to tolerate the voltage level output by 

a 5-cell pack over the long term, this is particularly true 

when the battery pack is freshly charged. Some of these 

servos react to this with a noticeable "grinding" sound. 

Therefore pay attention to the specifi cations of the 

servos you use before making a choice for a 5-cell 

battery pack..

LiFe 6.6 V batteries with 2 cells

From a contemporary perspective, these new cells are 

the very best choice. 

LiFe cells are also available in hard plastic casings to 

protect them from mechanical damage. Like LiPo cells, 

LiFe cells can be quick charged in suitable chargers and 

they are comparatively robust.

This type of secondary cell battery is also rated for a 

signifi cantly greater number of charge/discharge cycles 

than, for example, LiPo batteries The nominal 6.6 V 

output of a 2-cell LiFe battery pack does not present 

a problem for either Graupner HoTT receivers nor for 

those servos, speed controllers, gyros and other devices 

which have been specifi cally approved for operation in 

this – higher – voltage range. Please note however 

that practically all servos, speed controllers, gyros 

and other devices built in the past and most such 

devices currently still offered on the market have 

only a permissible voltage range of 4.8 to 6 V. Use 

of these batteries in conjunction with these devices 

demand use of a stabilized voltage regulator, e. g. the 

PRX, Order No. 4136, see appendix. Otherwise there is 

danger that attached devices will incur damage within a 

short period of time.

LiPo 2-cell packs

For a given capacity, LiPo batteries are lighter than, 
48 Installation notices

for example, NiMH batteries. LiPo batteries are also 

available in hard plastic casings to protect them from 

mechanical damage.

The comparatively high nominal voltage, 7.4 V, for a 

2-cell LiPo pack does not present a problem for either 

Graupner HoTT receivers nor for those servos, speed 

controllers, gyros and other devices which have been 

specifi cally approved for operation in this – higher – 

voltage range. Please note however that practically 

all servos, speed controllers, gyros and other 

devices built in the past and most such devices 

currently still offered on the market have only a 

permissible voltage range of 4.8 to 6 V. Use of these 

batteries in conjunction with these devices demand use 

of a stabilized voltage regulator, e. g. the PRX, Order 

No. 4136, see appendix. Otherwise there is danger that 

attached devices will incur damage within a short period 

of time.
Your notes 49
50 Term defi nitions

 Term defi nitions

Control function, control, function input, control channel, mixer, switch, control switch, fi xed switch

To make use of this mx-20 HoTT manual easier, a 

number of the terms used repeatedly throughout this 

manual have been defi ned below.

Control function

A "control function" is a signal intended to affect a 

given control action – initially independent of its signal 

course in the – . For example, this could be for throttle, 

ruder or aileron in a winged aircraft or pitch, roll or 

crow for a helicopter. A control function signal can 

be applied directly over a single control channel or 

also through a mixer and then applied over multiple 

control channels. A typical example of multiple control 

channels is separately operated aileron servos or the 

use of two roll or crow servos in helicopters. The control 

function explicitly includes the infl uence of the control's 

mechanical travel on the respective servo. 

Control

"Controls" include all operating elements on the 

transmitter, which are directly activated by the pilot, 

that impose an effect on servos, speed controllers etc. 

connected to the receiver. This includes: 

• both joysticks (control functions 1 through 4), even 

though these four control functions can be freely 

swapped around for both model types ("winged 

aircraft" and "helicopters") by use of software "Mode" 

settings, e. g. throttle left or right. The dual-axis 

function for throttle/airbrake is often referred to as the 

C1 control (channel 1).

• proportional rotary controls, which are the three 

CTRL 6, 7 + 8,

• the switches, SW 4/5 and 6/7, which are CTRL 9 and 10,

• switches SW 1 ... 3 as well as 8 and 9, if assigned to 

a control channel via the "Transm. controls" menu.

The proportional operating elements produce a direct 

effect on servos which is commensurate with the 

control's position whereas switch modules can only 

effect a two or three increment change.

Function input

This is an imaginary point in the signal path and must 

not be considered the same as the point on the circuit 

board where the transmitter control is connected. 

The choice of "controls arrangement" and settings 

in the "Transm. controls" menu have their effect 

"downstream" of this imaginary point of connection. 

Thus differences between the physical control's number 

and the number of the downstream control channel can 

indeed emerge.

Control channel

From the point at which a signal contains all control 

information necessary for a particular servo – whether 

directly from the physical control or indirectly by way of a 

mixer – the term "control channel" is used. This signal is 

only yet to be infl uenced by settings made in the "Servo 

adjustment" menu and the "Transmitter output" menu 

before it leaves the transmitter's RF module. 

Once it arrives at the receiver, this signal may still 

be modifi ed by settings made in the telemetry menu 

before fi nally being applied as a control quantity for the 

respective servo.

Mixers

The transmitter's software contains diverse mixer 

functions. These can be used to apply one control 

function to multiple servos or, conversely, to apply 

multiple control functions to a single servo. Please look 

over the numerous mixer functions in the text beginning 

on page 145 of this manual.

Switches

The three standard 2-position switches, SW 2, 3 and 

8, the two 3-position switches, SW 4/5 and 6/7, as well 

as both pushbutton switches, SW 1 and 9, can also be 

combined with control programming. However, these 

switches are generally intended for switching program 

options, e. g. to start and stop timers, to switch mixers 

on and off, or as a teacher/pupil switchover, etc. Each 

of these switches can be assigned any number of 

functions.

Appropriate examples are detailed in the manual.

Control switches

Since it is very practical to have some functions 

automatically switched on or off for a certain control's 

position (e. g. switch on/off of a stopwatch for acquisition 

of model run time, automatic extension of spoilers and 

other possibilities), four control switches have been 

integrated into mx-20 HoTT software.

These software switches, designated "G1 ... G4", are 

triggered by setting a switch-point along the physical 

control's course of travel. This "trigger setting" is simply 

defi ned with the press of a button. The switching 

action can be correlated to the physical control's travel 

direction by software.

Of course control switches can also be freely combined 

with the aforementioned physical switches to solve even 

more complex problems.

There is a series of instructive examples which make 

this programming child's play. Learn about this by taking 

advantage of the programming examples beginning on 

page 226.
Term defi nitions 51

Fixed switches FXI and FX

This type of switch turns a function permanently on, 

e. b. timers (closed fi xed switch) or off (open fi xed 

switch) or they can provide a fi xed input signal for a 

control function, e. g. FXI = + 100 % and FX = -100 %. 

For example, in fl ight phase programming, these fi xed 

switches can be used to switch a servo or speed 

controller between two settings.
52 Physical control, switch and control switch assignments

 Physical control, switch and control switch assignments

Principle procedure

The mx-20 Hott system exhibits maximum fl exibility 

when it comes to assigning standard equipment 

operating elements to specifi c functions.

Since the assignment of controls and switches is done 

in the same way, even though different menus may be 

involved, it is appropriate at this point to explain the 

fundamental programming technique so that users can 

concentrate on the particular contents when reading the 

detailed menu descriptions.

Physical control and switch assignments

The "Control adjust" menu can be used to assign 

transmitter inputs 5 ... 12 to operate servos, both from 

any given joystick direction (K1 ... K4) as well as to 

assign any other physical control designated "CTRL" 

or switch designated "SW". After tapping on the center 

SET key in the right key pad, the screen shown below 

will appear.

Move desired switch

or control adj.

Now simply activate the desired control (joystick 1 ... 4, 

CTRL 6 ... 10 or switch 1 ... 3, 8 or 9).

Notice:

Rotary controls, CTRL 6 ... 8, will not be recognized 

until they "detent". Therefore these controls can be 

turned back and forth until the correct assignment is 

shown in the screen. If adjustment travel is insuffi cient, 

activate the control in the other direction.

On the other hand, if you wish to assign a control in the 

"Control switch" menu, page 119, the "activate desired 

control" message will appear.

push desired switch

into position ON

Important notice:

Controls to be assigned (particularly CON TROL 6 ... 

10) MUST be pre-assigned in the "Control adjust" 

menu to one of the inputs 5 through 12!

Control assignment

Wherever programming permits a switch to be assigned, 

a switch symbol will appear in the screen's bottom 

display line.

Use the arrow keys in the left or right touch pad to select 

the appropriate column.

How to assign a switch

1. Briefl y press the SET-T key in the right touch pad. 

The message shown below will appear in the screen.

Move desired switch

to ON position

(ext. switch: SET )

2. Now it is only necessary to put the selected switch 

into the desired "ON" position or, as described at the 

right in "Assignment of external switches", to select 

a switch from the list of "External switches". This 

concludes the assignment. The switch symbol to the 

right of the switch's number indicates the current 

state of the particular switch.

Since CTRL 9 and 10 as well as the 3-position 

switches, SW 4/5 and 6/7, are not only usable as 

controls but also function as pure switches, there is a 

total of 9 switches ("SW 1 ... 9") available for use as 

desired.

Changing switch action 

If the activation of a switch is to result in the opposite 

action, put the switch or joystick in the desired OFF 

position, again activate the switch assignment and 

reassign the switch again so it will respond with the 

desired action.

Clear switch

A switch which has been assigned as described under 

point 1 can be cleared by simultaneously pressing the 

 or  key combination briefl y in the right key pad 

(CLEAR).

Assignment from the "external switch" list

Those menus in which the message ...

Move desired switch

to ON position

(ext. switch: SET )

... appears for switches designated with "SW" can be 

used to assign so-called "external switches.

Do this by confi rming the message text with the SET

key. A new window will appear with a list of the four 

control switches "C1 ... C4", followed by two so-called 

"FX" fi xed switches and the four inverted switches "C1i... 

C4i".
Physical control, switch and control switch assignments 53

Control/fix sw

C1 C2 C3 C4 FX

FXi C1i C2i C3i C4i

Use the arrow keys in the left or right key pad to select 

the desired switch then assign it with a brief tap on the 

center SET key of the right touch pad.

Notices:

• The two FX switches turn a function on "FXI" or off 

"FX " permanently.

• All other switches mentioned can have multiple 

assignments. Pay attention that you do not 

UNINTENTIONALLY assign reciprocally confl icting 

functions to a single switch. If necessary, note down 

the given switch functions.

Application examples:

• Shut-off of an on-board glow plug heater upon 

underrun or overrun of an idle threshold point 

programmed for the C1 joystick. In this case the glow 

plug heater switch is controlled by a transmitter mixer.

• Automatic switch on/off of the timer to measure pure 

"fl ight time" for a helicopter by way of a control switch 

on the throttle limiter.

• Automatic switch off of the "AI  Rud" when brake 

fl aps are extended, for example to adapt the roll of 

a model to the ground when making a landing on a 

slope without inducing a change of fl ight direction 

due to infl uence on the rudder.

• Extending landing fl aps with elevator trim adjustment 

during a landing as soon as the throttle stick is 

moved beyond its switch point. 

• Switch on/off of the timer for measuring the operating 

time of electric motors.

The control switches, freely programmable in the 

"Control switch" menu, can be incorporated into 

switch programming, i. e. assigned to a function instead 

of a "normal" switch. At those program locations 

where switches can be assigned you always have the 

opportunity to assign one of the control switches, C1... 

C4, instead of a physical switch by selecting one of 

these out of the list of "external switches".
54 Digital trim

 Digital trim

Functional description and description of C1 cut-off 

Digital trim with visible and audible indicators

Both joysticks are equipped for digital trimming. When 

you give the trim lever a brief push (one "click"), the 

neutral position of the associated joystick channel 

changes by one increment. If you hold the trim lever in 

one direction, the trim value changes continuously in the 

corresponding direction with increasing speed. 

These changes can be made "audible" by way of different 

frequency tones. This makes fi nding the mid-point during 

fl ight easy, without looking at the screen. When the midpoint is overrun, a brief pause will be inserted.

Current trim values are automatically stored when a 

model memory change is made. Furthermore, digital trim 

exercises fl ight phase specifi c control within a memory 

location (except for throttle/brake fl aps trim) – the socalled "C1" (channel 1) control function –.

This C1 trim includes yet another special function 

for winged aircraft and helicopter models, it allows 

the carburetor's idle setting to easily be found for a 

combustion motor. 

Since the trim functions described in these instructions 

are only effective in the direction "Motor off", the 

presentation in the screen of your transmitter may only 

change with respect to individual throttle or Pitch-min 

positioning of the C1 joystick in the "forward" or "back" 

direction, such as throttle/pitch "left stick" or "right stick". 

The illustrations in these instructions are always based 

on "Throttle/Pitch right" for both types of models and 

"Throttle back" for winged aircraft and helicopters. 

2. Helicopter models

In addition to the "Cut-off trim" function described 

below in "Winged aircraft models", C1 trimming also 

has another characteristic which is made possible by 

combining it with a so-called "Throttle limit" function see 

page 104. As long as the throttle limit control remains in 

the "left" half of its travel path, i. e. in the startup range, 

C1 trimming acts on the throttle servo as idle trim and the 

indication for idle trim is visible in the screen's display.

GRAUBELE

#01

3:33h

stop

 flt

K78

0:00

0:00

RX0.0V

5.2V

Last idle position

2.4 M

motor OFF position

CTRL 6

Throttle limit control

Current trim position

Trim at 

However, in contrast to winged aircraft models, the 

position indicator ( ) will be hidden and any preset idle 

position will be deleted when the throttle limit control is 

in the "right" half of its travel path.

GRAUBELE

#01

3:33h

Stop

Flt

K78

0:00

0:00

RX0.0V

5.2V

M 2.4CTRL 6

Throttle limit control

Notice for helicopters:

C1 trimming affects only the throttle servo, not the pitch 

servo. Notice also that the helicopter throttle servo must 

be connected to receiver output 6, see receiver layout 

on page 59.

1. Winged models

C1 trimming has a special cut-off trim function intended 

especially for combustion motors. This cut-off trim 

function is confi gured as follows. First put the motor into 

a safe idle speed. 

Now if you push C1 trim in a single motion toward its 

"Motor cut-off" direction until it is in its furthest travel 

position then an additional end-position marker will 

remain in the display. When the motor is restarted you 

can again immediately set the last idle speed with a 

single movement in the direction of "more gas". 

GRAUBELE

#01

3:33h

Stop

Flt

K78

0:00

0:00

RX0.0V

5.2V

Current 

trim position

Current trim position

2.4

Ch 1 trim lever

Idle direction

M

Trim at motor OFF position

This cut-off trim will be deactivated when "None" is 

entered on the "Motor at C1" line of the "Model Type"

menu, see page 82.

Notice:

Since this trim function is only effective in the "Motor 

off" direction, the display illustrated above will change 

appropriately if the C1 joystick's control direction for 

minimum throttle is changed from "back" to "front" (on 

which the above illustration is based) in the "Motor at 

C1" line of the "Basic Settings" menu.
Your notes 55
56 Winged models

 Winged models

Convenient support is provided for up to four aileron 

servos and four fl ap servos on normal models or, for 

V tail and fl ying wing/delta models, up to two aileron/

elevator servos plus four fl ap servos. 

The majority of motorized and glider models belong to 

the tail unit type "normal" and are equipped with one 

servo each for elevator, rudder and ailerons in addition 

to a motor throttle or electronic speed controller (or for 

brake fl aps in the case of a glider model). Beyond this, 

tail unit type "2HRSv3+8" permits the connection of two 

elevator servos to receiver outputs 3 and 8.

If ailerons, and conditionally the fl aps, are each actuated 

with two separate servos then settings can be made for 

differentiated control of all aileron and fl ap pairs in the 

"Wing mixers" menu, i.e. settings for downward ruder 

throw independent of upward throw. 

Finally, the position of fl aps can be controlled by a 

control out of group CTRL 6 ... 10. Alternatively, there 

is a phase-dependent trim function available for fl aps, 

ailerons and elevators in the "Phase trim" menu.

The "V tail unit" is to be selected from the "Model 

type" menu if the model has a V tail unit instead of 

a normal tail unit. This V tail unit selection provides 

coupled elevator and ruder control functions for both 

tail fl aps – each controlled by a separate servo – which 

handles both elevator and ruder functionality.

For delta and fl ying wing aircraft models, aileron and 

elevator functionality is affected by way of a common 

rudder fl ap on the trailing edge of each side (right and 

left) of the wing. The program contains appropriate mixer 

functions for both servos.

Up to 7 fl ight phases can be programmed into each of 

the 24 model memory locations. 

Except for C1 trim, digital trim will be stored on a 

fl ight-phase basis. C1 trim permits easy location of a 

carburetor idle setting.

Two timers are always available for fl ight operation. The 

transmitter operating time expired since the last battery 

charge is also displayed.

All transmitter controls (CTRL) and switches (SW) can 

be assigned in the "Control adjust" menu to inputs 5 

... 12 with almost no restrictions.

The "Dual Rate" and "Exponential" functions for ailerons, 

rudder and elevators are separately programmable and 

each are convertible between the two variations on a 

specifi c fl ight-phase basis.

In addition to 8 freely allocatable linear mixers, 4 

curve mixers ("Free mixers" menu) and 4 dual mixers 

("Dual mixer" menu), there are also fl ight-phase 

dependent 6-point curves for control channel 1 (throttle/

brake), see "Channel 1 curve" menu).

Depending on the number of wing servos, fi xeddefi nition mix and coupling functions can be selected 

from a list in the "Wing mixers" menu.

• Multi-fl ap menu: control of fl aps as ailerons, the 

infl uence aileron trim on fl aps controlled as ailerons, 

fl ap differentiation, fl ap function throw magnitude for 

all aileron and fl ap pairs, ailerons controlled as fl aps, 

elevator mixer  fl aps

• Brake settings: butterfl y, differential reduction, 

elevator curves

• aileron  rudder mixer

• fl aps  elevator mixer

Elevator Flap

Flap Elevator

F l a p Aileron

A il eron Flap

Aileron Rudder

Elevator Aileron

left

right Eel vator Flap

F al p Ele

A

vator ileron Rudder

Ailero n Flap

Airbrake Flap

Airbrake Elevator

Airbrake-Function 1

left

right

Rudder/Elevator

V-Tail

AI

FL

FL

AI

Brake FL, FL2

Brake Elevator

Brake AI, AI2 AI FL

FL2

AI FL FL2

AI2

FL  AI

FL  AI

EL  FL

RU  AI

EL  AI

EL  FL

AI2

AI  FL

AI  FL
Winged models 57

Installation notices 

Servos MUST be connected to the receiver in the 

sequence illustrated here. 

Outputs which are not needed are simply left empty. 

Also be sure to follow the notices on the next pages.

 Winged aircraft with and without motor, having up to 

4 aileron servos and up to 4 fl ap servos ...

... and tail plane type "normal" or "2 elevator 

servos" 

Receiver power supply

Free or left aileron 2 or aux. function

Free or right aileron 2 or aux. function

Rudder

Aileron or left aileron

Elevator or 1st elevator

Free or 2nd elevator or aux. function

Receiver power supply

Airbrake or throttle servo

or speed controller (electric motor)

Right aileron or aux. function

Flap or left flap

Right flap or free or aux. function

Free or left flap 2 or aux. function

Free or right flap 2 or aux. function

... and tail plane type "V tail unit"

Receiver power supply

Free or aux. function

Free or aux. function

Aileron or left aileron

Free or aux. function

Receiver power supply

Airbrake or throttle servo

or speed controller (electric motor)

Right aileron or aux. function

Flap or left flap

Right flap or free or aux. function

Free or left flap 2 or aux. function

Free or right flap 2 or aux. function

Left rudder / elevator

Right rudder / elevator

Delta/fl ying wing aircraft models with and without 

motor having up to two aileron/elevator servos and 

up to 2 fl ap/elevator servos 

Receiver power supply

Free or aux. function

Free or aux. function

Right elevon

Right elevon

Free or aux. function

Receiver power supply

Airbrake or throttle servo

or speed controller (electric motor)

Free or aux. function

Free or left flap / elevator

Free or right flap / elevator

Free or aux. function or left flap 2 / elevato

Free or aux. function or right flap 2 / elevat

Free or rudder

Because of orientation differences for installed servos 

and their rudder linkages, the actuating direction of 

some servos may be initially backward. The table below 

provides remedies.

Model 

type

 Servo actuation 

direction 

wrong

Remedy

V tail Rudder and 

elevator reversed

Reverse the polarity of 

servos 3 & 4 in the "Servo 

adjustment" menu

Rudder correct, 

elevators reversed

Swap the connections 

for servos 3 & 4 on the 

receiver

Elevators correct,

rudder reversed

Reverse the polarity of 

servos 3 & 4 in the "Servo 

adjustment" menu AND 

on the receiver

Delta,

fl ying 

wing

Elevator and 

aileron reversed

Reverse the polarity of 

servos 2 & 3 in the "Servo 

adjustment" menu

Elevator correct, 

aileron reversed

Reverse the polarity of 

servos 2 & 3 in the "Servo 

adjustment" menu AND 

on the receiver

Aileron correct, 

elevators reversed

Swap servos 2 & 3 at the 

receiver

All "program descriptions" for menus relevant to a 

winged aircraft model are marked with a winged aircraft 

symbol ...

... so only these menus need to be dealt with to program 

a winged aircraft model.
58 Helicopter models

 Helicopter models

Collective 

Pitch Curve

Swashplate 

Rotation

Roll Throttle

Pitch-Axis Throttle

Channel 1 Throttle

Roll Tail Rotor

Pitch-Axis Tail Rotor

Channel 1 Tail Rotor

Channel 1 Tail Rotor

Tail Rotor Throttle

The advanced developments incorporated into the 

transmitter as well as those now in helicopter models 

and their components like gyros, speed regulators, rotor 

blades, etc. make it possible to master a helicopter even 

in 3D acrobatic fl ight. On the other hand, a beginner 

needs only a few settings to get started with hovered 

fl ight training and then can take advantage of mx-20

HoTT features, step-by-step, with increasing expertise.

The mx-20 HoTT program can operate all 

conventional helicopters having 1 ... 4 servos for pitch 

control.

Six fl ight phases plus autorotation are available within 

a model memory, see menus "Control adjust", "Phase 

settings" and "Phase assignment".

As with winged aircraft, here too, in addition to the basic 

screen's standard timers there are additional timers 

as well as a lap counter with fl ight-phase-dependent 

stopwatch functionality which are available for selection 

(menus "Timers (general)" and "Fl. phase timers").

Except for pitch/throttle trimming, digital trimming can be 

stored as "global" for all fl ight phases or as "fl ight phase 

specifi c". C1 trim permits easy location of an idle setting.

The control assignments of inputs 5... 12 can be made 

common to every fl ight phase or separate ("Control 

adjust" menu).

A fl ight phase copy function is helpful during fl ight trials 

("Copy / Erase" menu).

"Dual Rate" and "Exponential" functions can be coupled 

for roll, nick and tail rotor and programmable in two 

variations in every fl ight phase.

There are 8 freely assignable linear mixers. There are 

also 4 curve mixers that can be programed and these 

can also be switched on or off, depending on the fl ight 

phase, in the "Mix active/Phase" menu. Beyond this, 

there are also 4 dual mixers available.

Available in the "Helicopter mixer" menu are fl ightphase-dependent 6-point curves for pitch, throttle and 

tail rotor mixer non-linear characteristics as well as two 

independent swashplate mixers each for roll and nick. 

Independent of this, the control curve of the channel 

1 joystick can be defi ned with up to 6 points in every 

fl ight phase. The beginner will initially only adapt the 

hover fl ight point to the control middle for the non-linear 

characteristics. 

Pre-programmed mixers in the "Helicopter mixer"

menu:

1. Pitch curve (6-point curve)

2. Channel 1  Throttle (6-point curve)

3. Channel 1  Tail rotor (6-point curve)

4. Tail rotor  Throttle

5. Roll  Throttle

6. Roll  Tail rotor

7. Nick  Throttle

8. Nick  Tail rotor

9. Gyro suppress

10. Swash rotation

11. Swash limiter

The "Throttle limit" function (input 12 in the "Control 

adjust" menu) allows the motor to be started in any 

fl ight phase. Control 6 – the proportional rotation control, 

CTRL 6 top left – is assigned to input 12 by default. This 

"throttle limiter" establishes – depending on its given 

position – the maximum possible carburetor position. 

This makes it possible for the motor to be controlled in 

the idle range, if necessary even by the proportional 

regulator. The throttle curves become effective only 

when the proportional regulator is pushed toward the full 

throttle direction.
Helicopter models 59

Notice for those transitioning from older Graupner 

systems:

In comparison to previous receiver layouts, servo 

connector 1 (pitch servo) and servo connector 6 

(throttle servo) have exchanged places. Servos must

be connected to receiver outputs as illustrated at the 

right in the bottom fi gure. Outputs which are not used 

are simply left empty. More details about respective 

swashplate types can be found on page 86 in the 

"Basic settings" menu.

Installation notices

Servos MUST be connected to the receiver in the 

sequence illustrated here. 

Outputs which are not used are simply left empty. 

Also be sure to follow the notices on the next pages.

Notice:

A speed regulator is also to be connected to receiver 

output "6" in order to take full advantage of the throttle 

limiter's convenience and safety features, see text 

beginning on page 104. See page 169 about this.

 Receiver layout for helicopter models ...

... with 1 to 3 swashplate servos

Receiver power supply

Free or aux. function

Free or aux. function

Tail rotor servo (gyro system)

Roll 1 servo

Pitch-axis 1 servo

Free or speed governor or aux. function

Receiver power supply

Collective pitch or roll 2 or 

Pitch-axis 2 servo

Free or aux. function

Throttle servo or speed controller

Gyro gain

Free or aux. function

Free or aux. function

... with 4 swashplate servos

Receiver power supply

Free or aux. function

Free or aux. function

Tail rotor servo (gyro system)

Roll 1 servo

Pitch-axis 1 servo

Free or speed governor or aux. function

Receiver power supply

Roll 2 servo

Pitch-axis 2 servo

Throttle servo or speed controller

Gyro gain

Free or aux. function

Free or aux. function

All menus relevant to helicopter models are marked 

in the "program descriptions" section with a helicopter 

symbol ...

... so only these menus need to be dealt with to program 

a helicopter model.
60 Detail program description - Loading a new memory location

Anyone who has worked through to this part of 

the manual has certainly already tried out a bit of 

programming. Nevertheless a detailed description of 

every menu should not be left out. 

This section begins with the loading of a "free" memory 

location, a procedure which would be performed if a new 

model was being "programmed".

GRAUBELE

#01

0:00h

Stop

Flt

K78

0:00

0:00

0.0V

5.9V

M

HoTT

From the base screen, a jump to the "Multi-function list" 

is made by tapping on the center SET button of the right 

touch pad. (The center ESC button of the left touch pad 

will cause a jump back to the base screen.) By default, 

when the multi-function list is called for the fi rst time 

after switching on the transmitter, the "Model select" 

menu item will be active and displayed in reverse video. 

If this is not the case, use the arrow keys (, ) of 

the left or right touch pad to select the "Model select" 

menu item ... 

Copy / Erase

Suppress menus 

Suppress models

Model select

Base setup model

Model type

... then (again) tap the center SET button of the right 

key pad.

 Detail program description

 Loading a new memory location

03

04

05

02  free 

01

06

R12

 free 

 free 

 free 

 free 

In the transmitter's delivered state, the fi rst model 

memory is initialized to the "winged aircraft" model 

type and the receiver in the delivery is bound to this 

model memory location, recognizable by the displayed 

receiver code at the right end of the line. In the above 

example, R12 is a code for the GR-24 receiver included 

in the set. In contrast, a "non-bound" model memory 

would appear with the code placeholder "---". 

The remaining memory locations, marked 

"free", are not occupied and thus also 

"non-bound". If you wish to program a winged aircraft 

model then, after leaving the "Model select" menu by 

tapping on the center ESC button of the left touch pad, 

programming of the model can begin right away ... or 

now use the  or  keys of the left or right touch pad 

to select one of the free memory locations ...

03

04

05

02  free 

01

06

R12

 free 

 free 

 free 

 free 

... and then tap on the center SET key of the right touch 

pad to confi rm the choice.

Afterward you will be prompted to select the basic model 

type, i.e. either "winged model" or "helicopter model".

Select model type

Use the  or  of the left or right key pad to select 

the basic model type then tap the center SET button 

in the right key pad. This initializes the selected model 

memory with the selected model type and the display 

will return to the base screen. The memory location is 

now accordingly occupied. 

On the other hand, if you wish to begin with a helicopter

then use the  or  keys of the left or right key pad to 

select a memory location labeled "free" and 

tap briefl y on the center SET button in the right key pad 

to confi rm your choice. You will be now be prompted to 

select the basic model type, i.e. either "winged model" or 

"helicopter model". Select the appropriate symbol with 

the  or  keys of the left or right touch pad then tap 

briefl y on the center SET button in the right touch pad to 

confi rm your choice. This initializes the selected model 

memory with the selected model type and you can now 

program your model into this model memory.

Changing over to another model type is still possible if 

you fi rst erase this memory location ("Copy / Erase"

menu, page 64).

Notice:

• If, from the base screen, the currently active model 

memory is to be erased then immediately after the 

erase action one of the two model types, "Winged" 

or "Heli" must be defi ned. You cannot avoid this 

selection even if you switch the transmitter off. When 
Detail program description - Loading a new memory location 61

notice that no failsafe settings have yet been made. 

More about this can be found on page 192. 

• If the screen should display the warning ...

Throttle

too

high !

... then move the throttle joystick, or the limiter for 

a helicopter, into its idle position; by default this is 

rotary control CTRL 6.

The appearance of this warning also depends on 

the "Motor at C1" or "Pitch min" in the "Model type" 

menu, refer to page 80 or "Helicopter type" page 84 

for the selected setting. For winged aircraft models, 

select "None" to deactivate this message if you have 

no motor to enter.

• If the transmitter already has occupied model 

memories then submenus of the "Copy / Erase" 

menu will display a pictogram of the selected model 

type at the respective memory location followed by a 

blank line or the model name which was entered in 

the "Basic settings " menu (see page 68 or 74) and 

any bond that may exist between a receiver and this 

model memory.

• switch If battery voltage is too low, you cannot

models for safety reasons. A corresponding message 

will appear in the display:

not possible now

voltage too low

As a basic principle, there are four different ways to 

assign the four control functions, aileron, elevator, 

rudder and throttle or brake fl aps for winged models 

the transmitter is switched on again the undesired 

occupation of the that model memory will have to be 

erased from another memory location.

In contrast, if a non-active memory location is erased, 

it will subsequently be marked as "free" in 

the "Model select" menu.

• After the selected model memory is initialized with 

the desired model type, the display will switch to the 

base screen of the freshly occupied model memory. 

At this time the warning ...

BIND N/A

OK

... will appear in the screen for a few seconds as 

notifi cation that a "bond" to a receiver does not exist. 

With a brief tap on the center SET button in the right 

touch pad you can jump directly to the appropriate 

option.

1

BD1 BD2

Mod.name

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

n/a

RF transmit OFF

Further details about binding a receiver can be found 

on page 69 or 75.

• After the aforementioned "BIND. N/A" warning 

message closes automatically, the warning ...

Fail Safe

setup

t.b.d.

... will appear (also for just a few seconds) to serve * N.N. = Nomen Nominandum (the name to be stated)

as well as rolling, pitching, tail rotor and throttle/pitch 

for helicopter models, to the two joysticks. Just which 

of these methods is used depends on the preferences 

of the individual model pilot. This function is set for the 

currently active model memory in the "Stick mode" line 

of the "Basic settings, model" menu, page 68 or 74.

1

bind n/a

SEL

R12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map n/a

A default value for this setting can be made for future 

models in the generalized "Basic Settings" menu, page 

216.

1

PPM10

SEL

BASIC SETTINGS

Own

Stick mode

DSC Output

Pitch min back

It should be noted here once again that, in the interest 

of greatest fl exibility in combination with the prevention 

of unintentional operating errors, no controls are 

preassigned to control channels 5 ... 12 by default.

This means that, in the system's delivered state, only 

servos attached to receiver outputs 1 ... 4 can be 

moved by the two joysticks and that any servos 

attached to receiver connectors 5 ... 12 (max) 

will remain in their middle positions. When a new 

helicopter model is initialized, servo 6 may perform a 

movement – depending on the throttle limiter's position, 
62 Detail program description - Loading a new memory location

CTRL 6 – . This condition changes for both model types 

only after the respective assignments have been made 

in the "Control adjust" menu.

On the other hand, if a newly initialized model memory 

is to be put into operation then it MUST fi rst be 

appropriately "connected" with one or more receivers 

before the servos attached to the receiver/s can be 

operated. More about this can be found in the section 

"Binding" on page 69 or 75. 

A fundamental description of programming steps for a 

winged aircraft model can be found in the programming 

examples section beginning on 226, or for helicopter 

models beginning on page 270.

The menu descriptions below are arranged in the 

sequence individual menus are listed in the multifunction list.
Detail program description - Model select 63

 Model select

Call up model 1 ... 24

The basic operation of the transmitters keys was 

explained on pages 24 and 25 and, on the previous 

double-page, explanations were provided for navigating 

to the multifunction list and about how to occupy a new 

model memory. At this point we now wish to begin with 

the "normal" description of individual menu items in the 

sequence they are arranged in the transmitter. Therefore 

we will begin with the menu ...

Model select

Copy / Erase

Suppress menus 

Suppress models

Model select

Base setup model

Model type

As many as 24 complete model settings, including 

digital trim values for trim levers, can be stored. 

Trimming is stored automatically such that a switchover 

from one model to another does not cause a loss of 

current trim settings. To the right of the model number, 

each occupied model memory line in this display shows 

a pictograph of the model type as well as the model's 

name entered for the model in its "Basic settings, 

model" menu, page 68 or 74 and the code, if present, 

for the receiver "bound" to the model memory location.

Select the "Model select" menu with the arrow keys of 

the left or right touch pad then press briefl y on the SET

button in the right touch pad.

01

03

04

05

02 ULTIMATE

GRAUBELE

STARLET

BELL47G

06

R12

R12

R12

–––

 free 

 free 

Now use the  arrow keys of the left or right touch 

pad to select the desired model memory from the list 

and activate the selection by pressing the SET button. 

Pressing the ESC button will cause a return to the 

previous menu page without activating a model change.

Notice:

• If a model change causes a "Throttle too high" 

warning to appear, the throttle/pitch joystick (C1) or 

the throttle limiter is too far in the full throttle direction.

• If a model change causes the message ...

BIND N/A

OK

... to appear then binding settings should be checked.

• If a model change causes the message ...

Fail Safe

setup

t.b.d.

... to appear then respective failsafe settings should 

be checked.

• If battery voltage is too low, the model switchover 

cannot be made due to reasons of safety. An 

appropriate message will appear in the screen.

not possible now

voltage too low
64 Detail program description - Copy / Erase

 Copy model  model

Select the "Copy model  model" sub-menu with the 

 arrow keys of the left or right touch pad then press 

the SET button.

SEL

0:00 –––

0:00

0:00

0s

0s

–––

–––

–––

–––

SEL

Timer1 0s

Timer2

Timer3

Lap time/tim tab

Lap Display

Select the model to be copied with the  arrow keys 

of the left or right touch pad ...

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV BIND. 1

... whereby a second activation of the SET button in the 

right touch pad will allow the "Copy to model" window 

for the destination memory to be selected with the 

 arrow keys of the left or right touch pad and then 

confi rmed with yet another press of the SET button or 

canceled with the ESC button. A memory location which 

is already occupied can be overwritten.

1

bind

BD1

GRAUBELE

BD2

R12

Mod.name

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

Rcv Ch Map n/a

1

SEL

Mod.name STARLET

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

n/a

RF transmit OFF

... to appear. A NO response will cause the process to be 

canceled and a return to the previous screen. Selecting 

the YES response with the  arrow keys of the left or 

right touch pad followed by confi rmation of the selection 

by briefl y pressing the SET button will erase the selected 

model memory.

Attention:

This erase process cannot be undone. All data in the 

selected model memory will be erased completely.

Notice:

If the currently active model memory is to be erased, 

a model type "Winged" or "Heli" must be defi ned 

immediately after the erase process. On the other hand, 

if an inactive memory location is to be erased then it 

will subsequently appear in the model select screen as 

"free".

 Copy / Erase

Erase or copy model  model, copy from or to SD card, copy fl ight phases 

Select the "Copy / Erase" menu with the  arrow 

keys of the left or right touch pad then briefl y press the 

SET button.

Suppress models

Model select

Base setup model

Model type

Copy / Erase

Suppress menus

 Erase model

Model select

Base setup model

Model type

Copy / Erase

Suppress models

Suppress: TOG

Select the "Erase model" sub-menu with the  arrow 

keys of the left or right touch pad then briefl y press the 

SET button.

Use the  arrow keys of the left or right touch pad to 

select the model to be erased ...

Model select

Base setup model

Model type

Copy / Erase

Suppress models

Suppress: TOG

... now the next time the SET button is pressed, it will 

prompt the confi rmation request ...
Detail program description - Copy / Erase 65

Once selection of the model memory has been 

confi rmed by pressing the SET button, a confi rmation 

request will appear.

modell really

ULTIMATE

to be copied?

NO YES

01

03 frei

A NO response will cancel the process and return the 

screen to the originating screen. If the  YES response 

is selected and confi rmed by activating the SET button 

then the selected source model will be copied into the 

selected model memory destination. 

Notice:

In addition to model data, binding data is also copied by 

this process. This means that a receiver system which 

was/is bound to the original model memory can also be 

operated by its copy without establishing the bond again.

 Export to SD

Select the "Export to SD" sub-menu with the  arrow 

keys of the left or right touch pad and press the SET

button.

=>

=>

=>

=>

Copy flight phase =>

Erase model

Copy model–>model

Export to SD

Import from SD

Select the model to be exported with the  arrow 

keys of the left or right touch pad.

01

03

04

05 frei 

02 ULTIMATE

GRAUBELE

STARLET

BELL47G

export to SD-CARD:

R12

R12

R12

–––

After confi rming the selected model memory by pressing 

the SET button, a confi rmation request will appear.

modell

ULTIMATE

export ?

NO YES

01

SD-Karte

A NO response will cancel the process and return the 

screen to the originating screen. However, if the  YES

response is selected then confi rmed by pressing the SET

button, the selected model will be copied to the SD card.

Notice:

• Should the notice ...

SD-CARD

INSERT

OK

... appear instead of a screen for model selection, 

there is no SD card in the transmitter's card slot, see 

page 22.

• In addition to model data, binding data is also copied 

by this process. This means that a receiver system 

which was/is bound to the original model memory 

can also be operated in the SAME transmitter by its 

copy without establishing the bond again.

• An exported winged aircraft model will be stored 

on the memory card in the \\Models\mx-20 folder 

with a fi lename format of "aModellname.mdl" 

and a helicopter model with a fi lename format 

of "hModellname.mdl". On the other hand, if a 

"nameless" model is exported, its data will be stored 

on the memory card under "ahNoName.mdl" or 

"hNoName.mdl", as appropriate.

• Some special characters that can be used in model 

names are subject to specifi c restrictions associated 

with the FAT or FAT32 fi le system used by the 

memory cards and these special characters will be 

replaced during the copy process with a tilde (~).

• A model fi le already on the memory having the same 

name as the fi le to be copied will be overwritten 

without warning.
66 Detail program description - Copy / Erase

01

03

04

02 ULTIMATE

GRAUBELE

STARLET

BELL47G

import to model:

05 free

R12

R12

R12

–––

After confi rming the selected model memory by pressing 

the SET button, a confi rmation request will appear.

modell

ULTIMATE

import ?

NO YES

01

03 free

A NO response will cancel the process and return the 

screen to the originating screen. However, if the  YES

response is selected and confi rmed by pressing the SET

button then the selected source model will be imported 

into the selected destination model memory. 

Notice:

• If the message ...

SD-CARD

INSERT

OK

... appears instead of a screen for model selection, 

there is no SD card in the transmitter's card slot, see 

page 22.

• In addition to model data, binding data is also 

imported by this process. This means that a receiver 

system which was/is bound to the original model 

memory can also be operated in the SAME transmitter 

 Import from SD

Select the "Import from SD" sub-menu with the 

arrow keys of the left or right touch pad and press 

the SET button.

=>

=>

=>

=>

Copy flight phase =>

Erase model

Copy model–>model

Export to SD

Import from SD

Select the model to be imported from the SD memory 

card with the  arrow keys of the left or right touch 

pad.

05 frei 

EXTRA

ALPINA

COBRA

BELL47G

import from SD-CARD:

11/03/10

11/03/11

11/03/11

11/03/12

Notice:

The export date posted at the right end of each model 

name line is represented in the format "year/month/day".

After again pressing the SET button in the right touch 

pad, the "import to model" window will appear Now 

the destination memory location can be selected with 

the  arrow keys of the left or right touch pad and 

confi rmed by pressing the SET button or the process 

can be canceled with the ESC button. A memory 

location which is already occupied can be overwritten.

by its copy without establishing the bond again.

 Copy from phase

Select the "Copy from phase" sub-menu with the 

arrow keys of the left or right touch pad then press the 

SET button.

=>

=>

=>

=>

Copy flight phase =>

Erase model

Copy model–>model

Export to SD

Import from SD

In the "Copy from phase" sub-menu ...

7

Copy from phase:

3

5 =>

=>

2

4

6

1

... the fl ight phase to be copied (1 ... 7 for winged 

aircraft models or 1 ... 6 for helicopter models) is 

selected with the arrow keys of the left or right touch pad 

then confi rmed by briefl y pressing the SET button in the 

right touch pad. The next window to appear will be the 

"Copy to phase" window. In that window the destination 

is to be selected and then also confi rmed. As described 

above, another confi rmation request will be issued.
Detail program description - Suppress menus and models 67

 Suppress menus

Hide menus in the multifunction 

Select the "Suppress menus" menu with the  arrow 

keys of the left or right touch pad then briefl y press the 

SET button.

Model select

Base setup model

Model type

Copy / Erase

Suppress menus

Suppress models

In the menu which then appears, menu items which 

are no longer needed or those which should not 

be changed, can be blocked from appearing in th 

multifunction list.

Model select

Base setup model

Model type

Copy / Erase

Suppress models

Suppress: TOG

This reduces the appearance of the multi-function list 

considerably, in some cases to only a few menus, 

thus substantially improving the clarity of the function 

selection list. Functions are not deactivated because 

they are hidden. They will simply no longer appear in the 

list. This also blocks direct access to these functions.

The function to be hidden or displayed is to be selected 

with the arrow keys of the left or right touch pad then 

its (hide/display) status switched-over by means of the 

center SET button in the right touch pad.

Model select

Base setup model

Model type

Copy / Erase

Suppress models

Suppress: TOG

Tip:

If you wish to forgo access-blockage to the multifunction list altogether, hide the "Code lock" menu 

in the multi-function list by way of this menu as a 

precautionary measure.

 Suppress models

Hiding model memory locations

Select the "Suppress models" menu with the  arrow 

keys of the left or right touch pad then briefl y press the 

SET button.

Model select

Base setup model

Model type

Copy / Erase

Suppress menus

Suppress models

Model memories which are rarely needed or to which 

access is to be blocked for other reasons can be hidden 

from the model selection list. This also clarifi es the 

overview layout for model selection.

A model to be hidden/displayed is selected with the 

arrow keys of the left or right touch pad then its status is 

switched-over by means of the center SET button in the 

right touch pad.

01

03

04

05

02 ULTIMATE

GRAUBELE

STARLET

BELL47G

E12

E12

E12

–––

 free

Suppress: TOG

A model memory which is "stricken through" will no 

longer appear in the "Model select" menu.
68 Detail program description - Base setup model

 Base setup model

Model-specifi c base settings for winged aircraft models

Before programming specifi c parameters, there are 

some basic settings to be made which effect the 

currently active model memory.

Select the "Base setup model" menu with the arrow 

keys of the left or right touch pad then press the center 

SET button in the right touch pad.

Model type

Suppress models

Base setup model

Servo adjustment

Control adjust

Stick mode

 Model name

Mod.name

Stick mode

RF BIND

1

n/a

BASIC SETTINGS, MODEL

n/a

BD1 BD2

RF transmit OFF

Change to the next screen page by pressing the SET

button briefl y. This will open a screen of characters for 

entry of the model's name. A maximum of 9 characters 

can be used to specify a model name.

 !"#$%&’()+,–./012

3456789:;

Mod Name GRAUB

FGHIJKLMNOPQRSTUVWX

YZ[¥]^_`abcdefghijk

?@A BCDE

Select the desired characters with the arrow keys of the 

left touch pad. Move to select the next character position 

by pressing the  arrow key of the right touch pad or its 

center SET button. Simultaneously pressing the  or 

 of the right touch pad (CLEAR) will place a space 

character at the position.

Positioning to any character position within the entry 

fi eld can be done with the  keys of the right touch 

pad.

A return to the previous menu screen is accomplished 

by pressing the center ESC button in the left touch pad.

After entering the model name it will appear in the base 

screen of the "Model select" menu and in the sub-menu 

for the "Copy /Erase" menu item.

 Stick mode

"MODE 2" (throttle left)

"MODE 3" (throttle right) "MODE 4" (throttle left)

"MODE 1" (throttle left)

Stick forward

Stick back

Rudder left

Rudder right

Motor full throttle

Motor idle

Aileron left

Aileron right

Motor full throttle

Rudder left

Rudder right

Motor idle

Stick forward

Stick back

Aileron left

Aileron right

Stick forward

Stick back

Aileron left

Aileron right

Motor full throttle

Motor idle

Rudder left

Rudder right

Motor full throttle

Motor idle

Aileron left

Aileron right

Stick forward

Stick back

Rudder left

Rudder right

There are four fundamental options for assigning the 

four control functions (aileron, elevator, rudder and 

throttle/brake fl ap) for a winged aircraft model to the two 

joysticks. Just which of these options is chosen depends 

on the individual preferences of the individual model 

pilot. 

Select the "Stick mode" line with the  arrow keys 

of the left or right touch pad. The option fi eld will be 

enclosed in a frame.

1

SEL

Mod.name GRAUBELE

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

n/a

RF transmit OFF

Press the SET button. The currently displayed stick 

mode will be displayed in inverse video. Now use the 

arrow keys of the right touch pad to select from among 

options 1 through 4.

Pressing simultaneously on the  or  keys of the 

right touch pad (CLEAR) will return the option selection 

back to stick mode "1".

Pressing the SET button again will deactivate option 

selection so that you can change to another line.

 Bound receiver 

Graupner HoTT receivers must be "instructed" to 

communicate exclusively with one particular model 

(memory) in a Graupner HoTT transmitter. This 

procedure is known as "binding" and must only be done 

once for every new receiver/model memory location 

combination (and can be repeated anytime).

Important notice:

During the binding procedure be sure the 

transmitter's antenna is always far enough away 

from the receiver's antenna. To be on the safe side, 

keep them at least one meter apart. Otherwise you 

run the risk of a faulty connection to the return 

channel and malfunctions will result.
Detail program description - Base setup model 69

 "RF bind " of transmitter and receiver

Use the  arrow keys of the left or right touch pad 

to move to the screen's "RF bind" line" then select the 

desired binding channel. For an example like that shown 

in the figure below, choose "BD2" because the binding 

channel designated as "BD1" in the screen's bottom line 

is already used by default for the receiver which was 

delivered with the set.

1

bind

BD1

GRAUBELE

BD2

R12

Mod.name

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

Rcv Ch Map n/a

If not already off, now switch the receiver on. The red 

LED on the receiver will blink.

Press and hold the SET button on the receiver while 

the LED continues to blink red for about 3 seconds then 

after about another 3 seconds begins to blink red/green. 

You can now release the SET button As long as this 

LED blinks red/green, the receiver is in bind mode.

Now, within this 3 second period, start the so-called 

"receiver binding" process for the receiver to the 

currently active model memory by briefl y pressing the 

center SET button of the right touch pad. At this time the 

screen's display will begin to indicate the duration of the 

"bond".

"Binding" multiple receivers per model

Multiple receivers per model can be bound if desired, 

whereby respective mx-20 HoTT programs offer the 

potential for managing a maximum of two receivers 

directly and for dividing up the 12 control channels (max) 

available on these two receivers as desired under menu 

control. Refer to additional details further down in this 

section. Binding two receivers is begun by fi rst binding 

the individual receivers as described below. 

In subsequent operation of the model only one of 

these receivers will establish a telemetry bond to 

the transmitter; the one which was activated in 

the "Tel. RCV" line of the "Telemetry" menu. For 

example:

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV BIND. 1

Any telemetry sensors which may be built into the model 

should therefore be connected to this receiver because 

the transmitter only receives and evaluates data from 

the return channel of the receiver activated on this line. 

The second, and all other receivers, operate in parallel 

but are fully independent in slave mode.

1

BD1

GRAUBELE

BD2

bind

R12

Mod.name

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

Rcv Ch Map n/a

Finding ...

If the receiver's LED, again blinking red, changes within 

about 10 seconds to continuous illumination in green, 

the binding process has been successfully completed. 

Your model-memory to receiver combination is now 

operationally ready. At this time the screen will now 

display "bind" (bound) instead of "n/a" (not attached). 

For example:

1

BD1

GRAUBELE

BD2

R08

bind

R12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

bind

On the other hand, should the LED on the receiver 

blink red for longer than about 10 seconds, the binding 

process has failed. In this case the screen will continue 

to show the status as "n/a". If this should happen, try 

changing the position of antennas then repeat the entire 

procedure.

Binding other receivers

The binding channel you have chosen is already bound 

(as indicated by the "bind" status). with another binding 

channel. After initiating the RF bind process, instead 

of displaying "BINDING", the message shown below 

appears.
70 Detail program description - Base setup model

1

BD1

GRAUBELE

BD2

R08

bind

R12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

bind

RF

must be

OFF

OK

Drop down two lines in the screen and switch off the 

RF module as described on the page in section "RF 

module". Afterward, return again to the "RF BIND" line 

and restart the process to dissolve bond as described 

on the previous page.

Alternatively you can briefl y switch off the transmitter 

then, after switching it back on again, respond to the 

message window that appears ...

RF on/off?

ON OFF

Please select

... with "OFF" ...

RF on/off?

ON

Please select

OFF

... then confi rm the selection by briefl y pressing the 

center SET button in the right touch pad. From the base 

screen jump again into the "RF BIND" line of the "Basic 

settings, model" menu and restart the binding process.

Dissolving a bond

Proceed as described above to initiate the binding 

process but WITHOUT fi rst putting a receiver in binding 

readiness.

 Receiver change map

1

BD1

GRAUBELE

BD2

R08

bind

R12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

bind

As mentioned in the introduction to the "Binding 

receivers" section, the mx-20 HoTT offers both the 

opportunity to freely divide up the transmitter's control 

channels within a receiver and the opportunity to 

distribute the transmitter's 12 control channels across 

two receivers. This redistribution is subsequently 

referred to as "mapping" or "channel mapping" (channel 

correlation). Select the receiver to be "mapped" with 

the arrow keys of the left or right touch pad then briefl y 

press the center SET button in the right touch pad.

Channel mapping within a receiver

Analogous to the channel correlation function in the 

"Telemetry" menu on page 212, described as "Channel 

Mapping", it is very simple to use this menu item to 

freely distribute the 12 control channels (inputs) to 

the outputs (servo connections) of the bound receiver 

specifi ed by column BD1.

RECEIVER CH – BIND1

In Ch 1 Out Ch 1

In Ch 2 Out Ch 2

In Ch 3 Out Ch 3

In Ch 4 Out Ch 4

After selection of the desired output with the arrow 

keys of the left or right touch pad, the corresponding 

input fi eld will be framed. Press briefl y on the center 

SET button in the right touch pad. The current setting is 

displayed in inverse video. Now select the desired input 

channel (= transmitter output, see page 206) with the 

arrow keys of the left or right touch pad.

Notice:

The number of lines available in the list (outputs) 

corresponds to the maximum number of servos which 

can be attached to the given receiver.

BUT CAUTION: If, for example, you have already 

specifi ed "2AIL" in the "Aile/fl aps" line of the "Model 

type" menu then the transmitter will have allocated 

control function 2 (ailerons) for left and right ailerons to 

control channels 2 & 5. The corresponding inputs (to the 

receiver) in this case would be channels 2 & 5 and these 

should be assigned accordingly, refer to the example 

below.

Examples:

• You would like to control each aileron of a large 

model with two or more servos. 

Assign each of the appropriate outputs (servo 

connections) to one and the same input (control 

channel). In the aforementioned case, to the 

giveninput of one of the two default aileron control 

channels (2 & 5) appropriate for the left or right wing.

• You would like to control the rudder of a large model 

with two or more servos. 

Assign each of the appropriate outputs (servo 

connections) to one and the same input (control 

channel). In this case, the default rudder channel (4), 

see fi gure bottom right.
Detail program description - Base setup model 71

Important notice:

By using the mx-20 HoTT transmitter's "Tx. output 

swap " option the transmitter's 12 control functions 

can be freely swapped in a similar manner or multiple 

outputs can be assigned to the same control function. 

To avoid confusion, it is strongly recommended that only 

one of these two options is used. 

Channel assignment on the second receiver

As already mentioned, the "Receiver channel mapping" 

option can be used to freely distribute the mx-20

HoTT transmitter's 12 control channels across two 

receivers, whereby the numbering sequence of outputs 

(servo connections) begun in the "BD1" column for 

bound "receiver 1" will be continued. For example, if 

"receiver 1" has enough connectors for 12 servos then 

the numbering of outputs in the "BD2" column (for the 

second bound receiver) will begin with 13.

RECEIVER CH – BIND2

In Ch12 Out Ch13

In Ch12 Out Ch14

In Ch12 Out Ch15

In Ch12 Out Ch16

After selection of the desired output with the arrow 

keys of the left and right touch pad, the corresponding 

input fi eld will be framed. Press the center SET button 

in the right touch pad The current setting is displayed 

in inverse video. Now select the desired input channel 

with the arrow keys of the right touch pad. For example, 

suitable to the above rudder example.

RECEIVER CH – BIND2

Input 4 Out Ch13

Input 4 Out Ch14

Input 4 Out Ch15

Input 4 Out Ch16

Notice:

The number of lines available (outputs) corresponds to 

the maximum number of servos which can be connected 

to receiver 2 and their numbering is dependent on the 

maximum number of servos which can be connected to 

receiver 1.

 RF transmit

This menu line provides an option for manually 

switching the transmitter's RF transmission on and off 

to specifi c models while the transmitter is in operation. 

For example, to save power while a model is being 

programmed. If this line option was set to OFF, it 

will be canceled (i.e. set to ON) the next time the 

transmitter is switched on.

If necessary, use the  arrow keys of the left or right 

touch pad to reach the "RF transmit"line then activate 

the option with by briefl y pressing the center SET button 

in the right touch pad

SEL

R12 R08

1

OFF

bind

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

bind

RF transmit

The right arrow keys can now be used to choose 

between OFF and ON. Again pressing the center SET

button in the right touch pad will complete the entry.

 Range test

The built-in range test reduces transmission power to an 

extent that a function test can be carried out even within 

a distance of up to about 50 m.

Perform the range test on the Graupner HoTT system 

according to the following instructions. If necessary, 

have someone assist you in carrying out the range test.

1. Preferably the receiver already bound to the 

transmitter should be installed into the model in its 

intended position.

2. Switch remote control on and wait for the receiver's 

green LED to light up. Now servo movements can be 

observed.

3. Place the model on a level surface (pavement, 

low-cut grass or bare ground) such that receiver 

antennas are at least 15 cm above ground level. It 

may be necessary to put something under the model 

to raise it up enough for this.

4. Hold the transmitter at hip level and at some distance 

from one's body. Do not point the antenna directly at 

the model but rather turn and/or kink the antenna's 

end so that it is oriented vertically during the test.

5. If necessary, use the  arrow keys of the left or 

right touch pad to reach the "RF Range Test"line in 

the menu then start range test mode by pressing the 

center SET button in the right touch pad.
72 Detail program description - Base setup model

SEL

RF Range Test 99sec

R12 R08

OFF

RF BIND bind

BASIC SETTINGS, MODEL

Rcv Ch Map

bind

RF transmit

When the range test is activated, the transmitter's 

output power will be signifi cantly reduced and the 

blue LED on the antenna's socket will begin to 

blink. At the same time, the timer display in the 

transmitter's screen will start counting down and 

every 5 seconds a two-frequency tone will sound.

GRAUBELE

#01

2:22h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

TEST 76s

Five seconds prior to the end of the range test a 

three-frequency tone will sound once every second. 

After expiration of the range test's 99th second the 

transmitter will again be switched to full output power 

and the blue LED will again illuminate constantly.

6. Move away from the model while manipulating 

the joysticks during this timespan. If you notice an 

interruption anytime while still within a distance of 

about 50 m, try to reproduce this malfunction.

7. If there is a motor in the model, it may be necessary 

to switch it on to further check noise immunity.

8. Continue moving away from the model until perfect 

control is no longer possible. 

9. Wait at this distance for the remainder of the test 

period with the still-operationally-ready model to 

expire. After the range test is ended it should again 

respond correctly to all RC controls. If this is not 100 

% the case, do not use the system. Contact your 

area's Graupner GmbH & Co. KG service partner.

10.Perform the range test before each fl ight and, in 

doing so, simulate all servo movements which also 

take place during fl ight. The range must always be 

at 50 m on the ground in order to assure safe model 

operation.

Attention:

Never start the range test on the transmitter during 

normal operation of the model.

 DSC output

If necessary, use the  arrow keys of the left or right 

touch pad to reach the "DSC output"line of the menu 

then activate this menu item by briefl y pressing the 

center SET button in the right touch pad.

SEL

99sec

DSC output PPM10

RF Range Test

R12 R08

OFF

BASIC SETTINGS, MODEL

Rcv Ch Map

RF transmit

Now you can use the right arrow keys to choose 

between three types of modulation "PPM10", "PPM18" 

and "PPM24". Pressing the center SET button in the 

right touch pad again will complete the entry.

This choice primarily infl uences the maximum number 

of control channels which can be attached to the DSC 

(direct servo control) socket, and thus also available to 

a fl ight simulator or teacher/pupil system. This maximum 

is control channels 1 ... 5 if "PPM10" is selected, control 

channels 1 ... 9 for "PPM18" and control channels 1 ... 

12 for "PPM24".

 Cut-off

Depending on the "idle forward or back" choice made 

in the "Motor at C1" line of the "Model type" menu, this 

motor "cut off" option can be coupled to a switch for 

throttling down a speed controller or to move a servo on 

the carburetor of a motor to the OFF (or idle) position. 

The motor OFF position (or idle setting) will then 

be preset by the left column directly over the "SEL" 

fi eld. The appropriate value for this entry fi eld is to be 

established through trial and error

A speed controller or throttle servo will only take on 

this preset position when a certain servo position or 

threshold is underrun and a switch is activated. This is 

done by setting the desired servo position (threshold 

value) into the middle column, directly over the "STO" 

fi eld then selecting the appropriate ON/OFF switch 

function in the right column.

• If the percentage value specifi ed for the middle 

column is greater than the current servo position, i. e. 

the current servo position lies below the threshold, 

the switchover will occur as soon as the switch is put 

into its ON position.

• If the percentage value specifi ed for the middle 

column is less than the current servo position, i. e. 

the current servo position is above the threshold, the 

speed controller will initially reduce motor speed or 

close the carburetor's throttle servo only to the extent 

dictated by the value in the left column as soon as 

the servo's position once underrunsthe threshold 

(max. +150 %) after the switch is changed over to its 
Detail program description - Base setup model 73

ON position.

The speed controller or throttle servo will remain in 

this cut-off position only until the selected switch is 

again changed over followed by a one-time throttle 

servo or speed controller movement beyond the preset 

threshold with the throttle/brake joystick control.

The factory setting for the left column is -100 % for 

the throttle servo "cut-off" position and a threshold of 

+150 % servo position setting in the middle column.

SEL

99sec

PPM10

cut off –100% +150% –––

STO

DSC Output

RF Range Test

OFF

BASIC SETTINGS, MODEL

RF transmit

Programming

To change the preset "cut-off" position of the throttle 

servo, press the center SET button in the right touch 

pad. The current setting will be displayed in inverse 

video. Now use the arrow keys of the left or right touch 

pad to set a value at which the motor is reliably "off". If a 

combustion motor is involved, be sure the throttle servo 

does not perform mechanical runout, e. g. -125 %.

SEL

OFF

99sec

PPM10

+150% –––

STO

cut off –125%

DSC output

RF Range Test

BASIC SETTINGS, MODEL

RF transmit

The – upper – preset value in the middle column 

ensures the motor can be stopped, throughout the 

maximum possible positioning range of the servo or 

speed controller, alone by the switch to be assigned in 

the right column. 

However, if you wish to set a lower threshold, by which 

an underrun will cause the throttle servo or speed 

controller with closed switch to switch into the cut-off 

position, reduce the preset servo travel from +150 % 

by placing the throttle servo or speed controller into 

the desired position with the throttle/brake joystick then 

press the center SET button in the right touch pad.

SEL

99sec

PPM10

–––

STO

cut off –125% +100%

DSC output

RF Range Test

BASIC SETTINGS, MODEL

RF transmit OFF

Finally, use the column at the right to specify a 

switch with which you can cut off the motor directly 

(emergency) or which will be activated by the threshold. 

SEL

99sec

PPM10

8

STO

cut off –125% +100%

DSC output

RF Range Test

BASIC SETTINGS, MODEL

RF transmit OFF

Notices:

• Be sure the throttle servo does not run out 

mechanically when the cut-off function is activated.

• A threshold over +100 % is reached by temporarily 

increasing the travel for servo 1 in the "Servo 

adjustment" menu to over 100 % then, after storing 

the threshold, change servo travel back to the 

original value. 
74 Detail program description - Base setup model | Helicopter

Before programming specifi c parameters, there are 

some basic settings to be made which effect the 

currently active model memory. Select the "Base setup 

model " menu with the arrow keys of the left or right 

touch pad then press the center SET button in the right 

touch pad.

Helicopter type

Suppress models

Base setup model

Servo adjustment

Control adjust

Stick mode.

 Model name

Mod.name

Stick mode

RF BIND

1

n/a

BASIC SETTINGS, MODEL

n/a

BD1 BD2

RF transmit OFF

Change to the next screen page by briefl y pressing 

the SET button in the right touch pad. This will open 

a screen of characters for entry of the model's name. 

A maximum of 9 characters can be used to specify a 

model name.

 !"#$%&’()+,–./012

3456789:;

Mod Name STARL

FGHIJK L MNOPQRSTUVWX

YZ[¥]^_`abcdefghijk

?@ABCDE

Select the desired characters with the arrow keys of the 

left touch pad. Move to select the next character position 

by pressing the  arrow key of the right touch pad or its 

center SET button Simultaneously pressing on the 

or  keys of the right touch pad (CLEAR) will place a 

space character at the position.

Positioning to any character position within the entry fi eld 

can be done with the  keys of the right touch pad.

A return to the previous menu screen is accomplished 

by pressing the center ESC button in the left touch pad.

A model name entered in this manner will appear in the 

base screen of the "Model select" menu and in the submenus of the "Copy / Erase" menu item.

 Stick mode

"MODE 2" (throttle left)

"MODE 3" (throttle right) "MODE 4" (throttle left)

"MODE 1" (throttle left)

TS-Nick

Tail

Nick

Tail

Motor/Pitch

Roll

Roll

Motor/Pitch

Tail

Tail

Motor/Pitch Motor/Pitch

Nick

Nick

Roll

Roll

Nick

Nick

Roll

Roll

Motor/Pitch

Motor/Pitch

Tail

Tail

Motor/Pitch

Motor/Pitch

Roll

Roll

Nick

Nick

Tail

Tail

Basically there are four different ways to assign the 

four helicopter control functions, roll, nick, tail rotor and 

throttle/pitch to the two joysticks. Just which of these 

is used depends on the preferences of the individual 

model pilot.

Use the  arrow keys of the left or right touch pad 

to select the "Stick mode" line. The option fi eld will be 

framed.

1

SEL

Mod.name STARLET

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

n/a

RF transmit OFF

Press the SET button. The currently displayed stick 

mode will be displayed in inverse video. Now use the 

arrow keys of the right touch pad to select from among 

options 1 through 4.

Pressing simultaneously on the  or  keys of the 

right touch pad (CLEAR) will return the option selection 

back to stick mode "1".

Pressing the SET button again will deactivate option 

selection so that you can change to another line.

 Bound receiver

Graupner-HoTT receivers must be "instructed " to 

communicate exclusively with one particular model 

(memory) in a Graupner-HoTT transmitter. This 

procedure is known as "binding" and must only be done 

once for every new receiver/model memory location 

combination (and can be repeated anytime).

Important notice:

During the binding procedure be sure the 

transmitter's antenna is always far enough away 

from the receiver's antenna. To be on the safe side, 

keep them at least one meter apart. Otherwise you 

run the risk of a faulty connection to the return 

channel and malfunctions will result.

"Binding" multiple receivers per model

Multiple receivers per model can be bound if desired, 

 Base setup model

Model-specifi c base settings for helicopter models
Detail program description - Base setup model | Helicopter 75

whereby respective mx-20 HoTT programs offer the 

potential for managing a maximum of two receivers 

directly and for dividing up the 12 control channels (max) 

available on these two receivers as desired under menu 

control. Refer to additional details further down in this 

section. Binding two receivers is begun by fi rst binding 

the individual receivers as described below. 

In subsequent operation of the model only one of 

these receivers will establish a telemetry bond to 

the transmitter; the one which was activated in 

the "Tel. RCV" line of the "Telemetry" menu. For 

example:

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV BIND. 1

Any telemetry sensors which may be built into the model 

should therefore be connected to this receiver because 

the transmitter only receives and evaluates data from 

the return channel of the receiver activated on this line.

The second, and all other receivers, operate in parallel 

but are fully independent in slave mode.

 "Binding" the transmitter and receiver

Use arrow keys of the left or right touch pad to 

move to the screen's "RF bind" line then select the 

desired binding channel. For an example like that shown 

in the figure below, choose "BD2" because the binding 

channel designated as "BD1" in the screen's bottom line 

is already used by default for the receiver which was 

delivered with the set.

1

bind

BD1

STARLET

BD2

R12 n/a

Mod.name

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

Rcv Ch Map

If not already off, now switch the receiver on. The red 

LED on the receiver will blink.

Press and hold the SET button on the receiver while 

the LED continues to blink red for about 3 seconds then 

after about another 3 seconds begins to blink red/green. 

You can now release the SET button As long as this 

LED blinks red/green, the receiver is in bind mode.

Now, within this 3 second period, start the so-called 

"receiver binding" process for the receiver to the 

currently active model memory by briefl y pressing the 

center SET button of the right touch pad. At this time the 

screen's display will begin to indicate the duration of the 

"bond".

1

bind

BD1

STARLET

BD2

R12 n/a

Mod.name

Stick mode

RF BIND n/a

BASIC SETTINGS, MODEL

Rcv Ch Map

Finding ...

If the receiver's LED, again blinking red, changes within 

about 10 seconds to continuous illumination in green, 

the binding process has been successfully completed. 

Your model-memory to receiver combination is now 

operationally ready. At this time the screen will now 

display "bind" (bound) instead of "n/a" (not attached). 

For example:

1

bind

BD1

STARLET

BD2

R08

bind

R12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

On the other hand, should the LED on the receiver 

blink red for longer than about 10 seconds, the binding 

process has failed. In this case the screen will continue 

to show the status as "n/a". If this should happen, try 

changing the position of antennas then repeat the entire 

procedure.

Binding other receivers

The binding channel you have chosen is already bound 

(as indicated by the "bind" status). with another binding 

channel. If, after initiating the RF bind process, the 

message shown below appears in the screen instead of 

displaying "BINDING"
76 Detail program description - Base setup model | Helicopter

1

bind

BD1

STARLET

BD2

R08

bind

R12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

RF

must be

OFF

OK

Drop down two lines in the screen and switch off the 

RF module as described on the page in section "RF 

module". Afterward, return again to the "RF BIND" line 

and restart the process to dissolve bond as described 

on the previous page.

Alternatively you can briefl y switch off the transmitter 

then, after switching it back on again, respond to the 

message window that appears ...

RF on/off?

ON OFF

Please select

... with "OFF" ...

RF on/off?

ON

Please select

OFF

... then confi rm the selection by briefl y pressing the 

center SET button in the right touch pad. From the base 

screen jump again into the "RF BIND" line of the "Basic 

settings, model" menu and restart the binding process.

Dissolving a bond

Proceed as described above to initiate the binding 

process but WITHOUT fi rst putting a receiver in binding 

readiness.

 Receiver change map

1

BD1

STARLET

BD2

bind

R08

bind

R12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

As mentioned in the introduction to the "Binding 

receivers" section, the mx-20 HoTT offers both the 

opportunity to freely divide up the transmitter's control 

channels within a receiver as well as the opportunity to 

distribute the transmitter's 12 control channels across 

two receivers. This redistribution is subsequently 

referred to as "mapping" or "channel mapping" (channel 

correlation). Select the receiver to be "mapped" with 

the arrow keys of the left or right touch pad then briefl y 

press the center SET button in the right touch pad.

Channel mapping within a receiver

Analogous to the channel correlation function in the " 

Telemetry " menu on page 212, described as "Channel 

Mapping", it is very simple to use this menu item to 

freely distribute the 12 control channels (inputs) to 

the outputs (servo connections) of the bound receiver 

specifi ed by column BD1.

RECEIVER CH – BIND1

In Ch 1 Out Ch 1

In Ch 2 Out Ch 2

In Ch 3 Out Ch 3

In Ch 4 Out Ch 4

After selection of the desired output with the arrow keys 

of the left and right touch pad, the corresponding input 

fi eld will be framed. Press briefl y on the center SET

button in the right touch pad. The current setting will be 

displayed in inverse video. Now select the desired input 

channel (= transmitter output, see page 206) with the 

arrow keys of the left or right touch pad.

Notice:

The number of lines available in the list (outputs) 

corresponds to the maximum number of servos which 

can be attached to the given receiver.

BUT CAUTION: If you wish to operate two servos with 

one control function, for example such as transmitter 

control function 2 (roll) which is divided up into 

control channels 1 & 2 for left and right roll servos by 

"3Sv(2Roll)" in the " in the "Heli Type" menu; then 

"map" transmitter outputs 1 & 2 (= inputs to the receiver) 

accordingly.

Important notice:

By using the mx-20 HoTT transmitter's "Tx. output 

swap" option, the transmitter's 12 control functions 

can be freely swapped in a similar manner or multiple 

outputs can be assigned to the same control function. 

To avoid confusion, it is strongly recommended that only 

one of these two options is used. 

Channel assignment on the second receiver

As already mentioned, the "Receiver channel mapping" 

option can be used to freely distribute the mx-20

HoTT transmitter's 12 control channels across two 

receivers, whereby the numbering sequence of outputs 

(servo connections) begun in the "BD1" column for 

bound "receiver 1" will be continued. For example, if 

"receiver 1" has enough connectors for 12 servos then 

the numbering of outputs in the "BD2" column (for the 
Detail program description - Base setup model | Helicopter 77

second bound receiver) will begin with 13.

RECEIVER CH – BIND2

In Ch12 Out Ch13

In Ch12 Out Ch14

In Ch12 Out Ch15

In Ch12 Out Ch16

After selection of the desired output with the arrow keys 

of the left and right touch pad, the corresponding input 

fi eld will be framed. Press the center SET button in the 

right touch pad The current setting will be displayed 

in inverse video. Now select the desired input channel 

with the arrow keys of the right touch pad. For example, 

appropriate for the above example with roll servos:

In Ch 2 Out Ch14

In Ch12 Out Ch15

In Ch12 Out Ch16

RECEIVER CH – BIND1

In Ch 1 Out Ch13

Notice:

The number of lines available (outputs) corresponds to 

the maximum number of servos which can be connected 

to receiver 2 and their numbering is dependent on the 

maximum number of servos which can be connected to 

receiver 1.

 RF transmit

This menu line provides an option for manually 

switching the transmitter's RF transmission on and off 

to specifi c models while the transmitter is in operation. 

For example, to save power while a model is being 

programmed. If this line option was set to OFF, it 

will be canceled (i.e. set to ON) the next time the 

transmitter is switched on.

If necessary, use the arrow keys of the left or right 

touch pad to reach the "RF transmit " line then activate 

the option by briefl y pressing the center SET button in 

the right touch pad.

SEL

R12 R08

1

OFF

bind

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

bind

RF transmit

The right arrow keys can now be used to choose 

between OFF and ON. Again pressing the center SET

button in the right touch pad will complete the entry.

 Range test

The built-in range test reduces transmission power to an 

extent that a function test can be carried out even within 

a distance of up to about 50 m.

Perform the range test on the Graupner HoTT system 

according to the following instructions. If necessary, 

have someone assist you in carrying out the range test.

1. Preferably the receiver already bound to the 

transmitter should be installed into the model in its 

intended position.

2. Switch remote control on and wait for the receiver's 

green LED to light up. Now servo movements can be 

observed.

3. Place the model on a level surface (pavement, 

low-cut grass or bare ground) such that receiver 

antennas are at least 15 cm above ground level. It 

may be necessary to put something under the model 

to raise it up enough for this.

4. Hold the transmitter at hip level and at some distance 

from one's body. Do not point the antenna directly at 

the model but rather turn and/or kink the antenna's 

end so that it is oriented vertically during the test.

5. If necessary, use the arrow keys of the left or 

right touch pad to reach the "RF Range Test" line in 

the menu then start range test mode by pressing the 

center SET button in the right touch pad.

SEL

RF Range Test 99sec

R12 R08

OFF

RF BIND bind

BASIC SETTINGS, MODEL

Rcv Ch Map

bind

RF transmit

When the range test is activated, the transmitter's 

output power will be signifi cantly reduced and the 

blue LED on the antenna's socket will begin to 

blink. At the same time, the timer display in the 

transmitter's screen will start counting down and 

every 5 seconds a two-frequency tone will sound.

STARLET

#02

2:22h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

TEST 76s

Five seconds prior to the end of the range test a 

three-frequency tone will sound once every second. 

After expiration of the range test's 99th second the 

transmitter will again be switched to full output power 
78 Detail program description - Base setup model | Helicopter

SEL

99sec

DSC output PPM10

RF Range Test

R12 R08

OFF

BASIC SETTINGS, MODEL

Rcv Ch Map

RF transmit

Now you can use the right arrow keys to choose 

between three types of modulation "PPM10", "PPM18" 

and "PPM24". Pressing the center SET button in the 

right touch pad again will complete the entry.

This choice primarily infl uences the maximum number 

of control channels which can be attached to the DSC 

(direct servo control) socket, and thus also available to 

a fl ight simulator or teacher/pupil system. This maximum 

is control channels 1 ... 5 if "PPM10" is selected, control 

channels 1 ... 9 for "PPM18" and control channels 1 ... 

12 for "PPM24".

 Autorotation

Autorotation is that state of descending fl ight in which 

the pitch of main rotor blades are set such that the 

rotor's speed matches the natural forces of air fl owing 

through, like a windmill. This built-up energy can be 

used for "recovery" lift to brake a descent by appropriate 

blade pitch adjustment.

Autorotation is a means by which real and model 

helicopters are able to land safely in emergency 

situations, e. g. in the event of a motor failure. However, 

the prerequisite for this is a well-trained pilot familiar 

with the helicopter's characteristics. Quick reaction and 

good perceptiveness are necessary because the rotor's 

inertia can only be used once to generate recovery lift.

When this technique is evaluated during competitions, 

the motor must be switched off for autorotation. For 

training purposes it is better to keep the motor running 

at idle during autorotation.

The Autorotation switch causes a switchover to the 

autorotation fl ight phase in which control of "throttle" and 

"pitch" are separate and all mixers which have an effect 

on the throttle servo are switched off. Corresponding 

parameter settings are made in the "Helicopter mixer" 

menu (see page 178); refer also to the "Principle of the 

Auto. C1 Pos." topic which follows.

The "Autorotation" name is permanently assigned to 

phase 1 and it is included in the base screen of all 

fl ight phase dependent menus. This name can NOT 

be changed. It is only possible to assign a switch to 

this option, as described on page 52. If a switch is 

assigned, it will have absolute priority over all other 

fl ight-phase switches.

Input

Output

Point ?

0%

0%

–100%

C1

Normal

Thr

Curve off

More about fl ight-phase programming can be found 

in the text beginning on page 164 in the "Helicopter 

mixer" section.

 Auto.C1 Pos. (Autorotation C1 position)

The autorotation fl ight-phase can alternatively be 

activated by a threshold point for the C1 throttle/pitch 

joystick. To set such a threshold, use the  arrow 

keys of the left or right key pad to reach the "Auto.C1 

Pos." line. 

and the blue LED will again illuminate constantly.

6. Move away from the model while manipulating 

the joysticks during this timespan. If you notice an 

interruption anytime while still within a distance of 

about 50 m, try to reproduce this malfunction.

7. If there is a motor in the model, it may be necessary 

to switch it on to further check noise immunity.

8. Continue moving away from the model until perfect 

control is no longer possible. 

9. Wait at this distance for the remainder of the test 

period with the still-operationally-ready model to 

expire. After the range test is ended it should again 

respond correctly to all RC controls. If this is not 

100 % the case, do not use the system. Contact your 

area's Graupner GmbH Co. KG service partner.

10. Perform the range test before each fl ight and, in 

doing so, simulate all servo movements which also 

take place during fl ight. The range must always be 

at 50 m on the ground in order to assure safe model 

operation.

Attention:

Never start the range test on the transmitter during 

normal operation of the model.

 DSC output

If necessary, use the  arrow keys of the left or right 

touch pad to reach the "DSC output"linethen activate 

this menu item by pressing the center SET button of the 

right touch pad.
Detail program description - Base setup model | Helicopter 79

As soon as this line has been selected, the value fi eld 

in its column directly above STO on the screen's bottom 

line will be framed.

99sec

PPM10

–––

Auto.C1 Pos. 0% –––

STO

DSC Output

Autorotation

BASIC SETTINGS, MODEL

RF Range Test

Move the C1 joystick into the desired threshold 

switchover position then press the center SET button in 

the right touch pad. The current value will be displayed, 

e. g.:

99sec

PPM10

–––

-55% –––

STO

Auto.C1 Pos.

DSC Output

Autorotation

BASIC SETTINGS, MODEL

RF Range Test

After this has been done, use the arrow keys to move 

into the column above the switch symbol then assign a 

switch to this fi eld, as described on page 52 in section 

"Switches, controls and control switches". Preferably the 

selection will be one of the two self-resetting switches, 

SW 1 or 9.

99sec

PPM10

–––

-55%

STO

Auto.C1 Pos. 9

DSC Output

Autorotation

BASIC SETTINGS, MODEL

RF Range Test

Once this activation switch is closed, the fi rst occurrence 

of a threshold underrun will cause the program to switch 

over to "Autorotation" and then remain independent of 

C1 position in this fl ight phase until the activating switch, 

in this example SW 9, is again "OFF".

"Auto. C1 Pos." has precedence over all other fl ightphase switches.

Corresponding parameter settings for ...

• pitch servos

• throttle servo

• tail rotor servo

• swashplate rotation, if available

• gyro setting

... are made in the "Helicopter mixer" menu, see 

page 64.

 Cut-off

Within the framework of autorotation settings for the 

mx-20 HoTT transmitter's helicopter program, there 

are parameters for an emergency "cut off" of the throttle 

servo or motor actuator, refer to the programming 

proposal on page 286. However, this option is not 

available if an idle position is specifi ed in the "Thr 

setting AR" line of the "Helicopter mixer" menu 

instead of an (emergency) OFF position; for example, 

to avoid restarting the motor after every landing during 

autorotation practice. In this case it is better to use this 

option as a "cut off" rather than as an emergency OFF 

solution. 

Depending on the "forw./back" choice made for the 

"Pitch min" line of the "Heli Type" menu, this motor "cut 

off" option can be coupled to a switch for throttling down 

a carburetor servo to the cut-off (or idle) position. 

This cut-off (or idle) position is specifi ed by the left 

column over the "SEL" fi eld and its value is to be 

established through trial and error.

A speed controller or throttle servo will only take on 

this preset position when a certain servo position or 

threshold is underrun and a switch is activated. This is 

done by setting the desired servo position (threshold 

value) into the middle column, directly over the "STO" 

fi eld then selecting the appropriate ON/OFF switch 

function in the right column.

• If the percentage value specifi ed for the middle 

column is greater than the current servo position, i. e. 

the current servo position lies below the threshold, 

the switchover will occur as soon as the switch is put 

into its ON position.

• If the percentage value specifi ed for the middle 

column is less than the current servo position, i. e. 

the current servo position is above the threshold, the 

speed controller will initially reduce motor speed or 

close the carburetor's throttle servo only to the extent 

dictated by the value in the left column as soon as 

the servo's position once underruns the threshold 

(max. +150 %) after the switch is changed over to its 

ON position.

The speed controller or throttle servo will remain in 

this cut-off position only until the selected switch is 

again changed over followed by a one-time throttle 

servo or speed controller movement beyond the 

preset threshold with the throttle/brake joystick 

control.

The factory setting for the left column is -100 % for 

the throttle servo "cut-off" position and a threshold of 

+150 % servo position setting in the middle column.
80 Detail program description - Base setup model | Helicopter

PPM10

–––

-55% 9

SEL

cut off –100% +150% –––

STO

Auto.C1 Pos.

DSC Output

Autorotation

BASIC SETTINGS, MODEL

Programming

To change the preset "cut-off" position of the throttle 

servo, press the center SET button in the right touch 

pad. The current setting will be displayed in inverse 

video. Now use the arrow keys of the left or right touch 

pad to set a value at which the motor is reliably "off" 

without a startup of the throttle servo. For example 

-125 %:

PPM10

–––

-55% 9

SEL

+150% –––

STO

cut off –125%

Auto.C1 Pos.

DSC Output

Autorotation

BASIC SETTINGS, MODEL

The – upper – preset value in the middle column 

ensures the motor can be stopped, throughout the 

maximum possible positioning range of the servo or 

speed controller, alone by the switch to be assigned in 

the right column. 

However, if you wish to set a lower threshold, by 

which an underrun will cause the throttle servo or 

speed controller with closed switch to switch into the 

cut-off position, reduce the preset servo travel and - if 

applicable, the throttle limiter - by placing the throttle/

pitch joystick into the desired position then press the 

center SET button in the right touch pad.

PPM10

–––

-55% 9

SEL

+100% –––

STO

cut off –125%

Auto.C1 Pos.

DSC Output

Autorotation

BASIC SETTINGS, MODEL

Finally, use the column at the right to specify a 

switch with which you can cut off the motor directly 

(emergency) or which will be activated by the threshold. 

PPM10

–––

-55% 9

SEL

+100%

STO

cut off –125% 1

Auto.C1 Pos.

DSC Output

Autorotation

BASIC SETTINGS, MODEL

Notices:

• Be sure the throttle servo does not run out 

mechanically when the cut-off function is activated.

• A threshold over +100 % is reached by temporarily 

increasing the travel for servo 1 in the "Servo 

adjustment" menu to over 100 % then, after storing 

the threshold, change servo travel back to the 

original value. 
Your notes 81
82 Detail program description - Model type

This "Model type" menu is used to establish the 

type of model to be programmed. This also activates 

all characteristic mixers, coupling functions, etc. 

in preparation for subsequent programming of the 

specifi ed model type.

Suppress model

Base setup model

Servo adjustment

Control adjust

Model type

Stick mode.

Press briefl y on the center SET button in the right touch 

pad.

 Motor at C1

After selecting the "Motor at C1" line with the  arrow 

keys of the left and right touch pad, the corresponding 

entry fi eld will be framed. 

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1 +100%

SEL

Press briefl y on the center SET button in the right touch 

pad. The current setting will be displayed in inverse 

video. Now use the arrow keys of the right touch pad to 

select from among the following four options: 

"none" For operation of a model without a 

propulsion.

 The warning "Throttle too high", see 

page 36, is deaktivated and the "Brake 

settings" sub-menu of the "Wing 

mixers" menu (beginning page 146) is 

available without any restrictions.

"back": The idle position for the throttle/brake 

fl aps control stick (C1) is to the rear, i. e. 

toward the pilot.

 The warnings "Throttle too high", see 

page 36, as well as the "cut off" option 

in the "Basic settings, model" menu, 

see page 72, are activated and the 

"Brake settings" sub-menu of the "Wing 

mixers", beginning page 146, will be 

available if the entry in the "Motor" 

column of the "Phase settings" menu, 

page 128 for the currently active fl ight 

phase contains "none".

"forw.": The idle position for the throttle/brake 

fl aps control stick (C1) is at the front, i. e. 

away from the pilot.

 The warnings "Throttle too high", see 

page 36, as well as the "cut off" option 

in the "Basic settings, model", see 

page 72, are activated and the "Brake 

settings" sub-menu of the "Wing 

mixers", beginning page 146, will be 

available if the entry in the "Motor" 

column of the "Phase settings" menu, 

page 128 for the currently active fl ight 

phase is "none".

Notice:

• Be sure to pay attention during the programming 

procedures that motors do not start up 

unintentionally. Disconnect the fuel supply or 

battery terminals to motors before programming.

• C1 trimming will operate according to your choice 

between "normal" or only "back" or "fwd.", that is, 

either over the control's entire travel path or only in 

the respective idle direction.

• cut off trim" function described Pay attention to the "

on page 54. 

 Tail type

After selecting the "Tail type" line with the  arrow 

keys of the left or right touch pad, the corresponding 

entry fi eld will be framed.

+100%

SEL

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1

Press briefl y on the center SET button in the right touch 

pad. The current setting will be displayed in inverse 

video. Now select the type applicable to your model with 

the arrow keys of the right touch pad.

"normal": Elevators and rudder are each operated 

by a single servo.

"V-tail": Elevator and rudder control is affected 

by way of two separate, articulated, 

V-shaped rudders. The coupling function 

for rudder and elevator control will be 

automatically taken over by the program. 

The relationship of rudder-to-elevator 

proportion is set in the "Dual Rate / 

Expo" menu, page 108 and servo travel 

in the "Servo adjust" menu, page 90.

 If differentiated rudder throw is also 

desired then the V-tail should be 

 Model type

Establishing winged aircraft model type
Detail program description - Model type 83

controlled instead by way of the "Dual 

mixer" menu, page 194. In this case 

however, the tail type entry specifi ed here 

must be "normal". 

"Delta/fl ": Aileron and elevator control is operated 

by one or two servos per wing half. 

However, elevator trimming is also 

affected by selecting the "QR 2WK" 

option – see below – but only on servos 2 

& 3. 

"2HRSv3+8": This option is intended for models 

with two elevator servos. The servo 

connected to output 8 will operate in 

parallel with servo 3 to actuate elevators. 

Elevator trimming affects both servos.

Notice about the "2HRSv3+8" option:

One control, which assigns input 8 by 

way of the "Control adjust" menu, is 

then disconnected from servo "8" by 

software for reasons of safety i. e. it is 

made ineffective.

 Aileron/Flaps

After selecting the "Aile/fl aps" line with the  arrow 

keys of the left or right touch pad, the corresponding 

entry fi eld will be framed.

+100%

SEL

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1

Press briefl y on the center SET button in the right touch 

pad. The current setting will be displayed in inverse 

 Brake offset

This function not only has potential for gliders and 

electric models but also for models with combustion 

motors and landing fl aps.

The mixers described in the "Brake settings" line of 

the "Wing mixers" menu can be operated by the C1 

control stick ("input 1") or another transmitter operating 

element which has been assigned to input 7, 8 or 9 in 

the "Control adjust" menu. In this latter case, retain 

the "GL" default setting for the "Type" column in the 

"Control adjust" menu so the selected control can 

operate independent of fl ight phase. 

In the majority of cases the default setting for "input 1" 

will remain as it is and the brake will be operated by way 

of the non-neutralizing C1 joystick. 

However, use of input 7, 8 or 9 makes it possible to 

operate the brake in an alternative manner, even by way 

of a supplementary control, if the C1 stick is to be used 

for something else.

The neutral point (offset) can be set to any desired 

position. This is done by placing the control for input 1, 

7, 8 o 9 into the position at which the landing fl aps are to 

be in their neutral position then fi xing this "Offset" point 

there with STO.

+90%

STO SEL

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1

If the offset point is not set at the far end of control 

element travel, the remainder of travel to the end point 

will be "free travel", i. e. this "free travel" will no longer 

video. Now use the arrow keys of the right touch pad to 

select the number of wing servos to be programmed for 

the model.

Available Control channel used

1QR 2

1QR 1WK 2 | 6

2QR 2 + 5

2QR 1WK 2 + 5 | 6

2QR 2WK 2 + 5 | 6 + 7

2QR 4WK 2 + 5 | 6 + 7 / 9 + 10

4QR 2WK 2 + 5 / 11 + 12 | 6 + 7

4QR 4WK 2 + 5 / 11 + 12 | 6 + 7 / 9 + 10

Depending on the option selected here, the given mixers 

needed and their settings will be activated in the "Wing 

mixers", menu beginning page 146.

Tips:

• Settings for all wing fl ap pairs (QR and QR2, WK and 

WK2) can be trimmed on a fl ight-phase basis in both 

the "Phase trim" menu and in the "Wing mixers" 

menu, page 146.

• The functionality of all wing fl ap pairs (QR and QR2, 

WK and WK2) can also be operated by way of the 

"Throttle/brake-fl ap stick" if this stick has not been 

assigned to other use, e. g. for certain brake settings, 

see "Wing mixers" menu, page 146. To confi gure 

this it is only necessary to assign "Control 1" to input 

6 in the "Control adjust" menu, page 96. (If you 

would rather operate fl aps with switches, one of the 

transmitter's two or three position switches are good 

for this purpose.)
84 Detail program description - Model type

infl uence any mixer available for "Brake settings" in 

the "Wing mixers" menu. This free travel ensures that, 

even if the brake fl ap control is not quite positioned to 

its full end of travel, it will still stop all brake settings at 

"neutral". At the same time, the effective control path is 

automatically spread to 100 %.

Tip:

Preferably, the servo intended for operating any airbrake 

fl aps that may be on the model should be connected to 

the receiver output operated by the brake input channel, 

e. g. connect airbrake servo onto (free) receiver output 8 

if input 8 has been chosen for the "brake", etc. A second 

airbrake servo is most conveniently operated by way of 

a free mixer.
Your notes 85
86 Detail program description - Helicopter type

 Helicopter type

Establishing helicopter model type

This "Model type" menu is used to establish the 

type of model to be programmed. This also activates 

all characteristic mixers, coupling functions, etc. 

in preparation for subsequent programming of the 

specifi ed model type.

Suppress models

Base setup model

Servo adjustment

Control adjust

Helicopter type

Stick mode

Press briefl y on the center SET button in the right touch 

pad.

 Swashplate type

Control of the swashplate will require an appropriate 

program variant which corresponds to the number of 

servos operating pitch control. 

After selecting the "Swashplate" line with the 

 arrow keys of the left or right touch pad, the 

corresponding entry fi eld will be framed.

Linear. swashpl.

Swashplate

no

1 Servo

Rotor direct right

HELI TYPE

Pitch min. back

SEL

Press briefl y on the center SET button in the right touch 

pad. The current setting for number of pitch servos will 

be displayed in inverse video. Now choose the variant 

needed with the arrow keys of the right touch pad.

"1 Servo": The swashplate will be tipped with one 

servo each for roll and nick. Pitch control 

will be affected by a separate servo.

 (Since helicopter models operated 

with only 1 pitch servo will be operated 

WITHOUT the transmitter's mixer 

functions for pitch, nick and roll, the 

"Swashplate mixer" menu item in the 

Multifunction menu will be hidden.)

"2 Servos": Two roll servos will displace the 

swashplate axially to affect pitch control; 

nick control will be decoupled by a 

mechanical compensation rocker.

"3Sv (2Roll)": Symmetrical three-point control of 

the swashplate is affected at three 

articulation points, each radially offset 

from the others by 120°, which are 

connected to one nick servo (at the 

front orrear) and two roll servos (located 

laterally at the left and right). All three 

servos push the swashplate axially to 

affect pitch control.

"3Sv (140)": Asymmetrical three-point control of 

the swashplate is affected at three 

articulation points connected to one nick 

servo (rear) and two roll servos (front 

left and right). All three servos push the 

swashplate axially to affect pitch control.

"3Sv (2Nick)": Symmetrical three-point control as 

described above but radially offset by 

90°, one lateral roll servo and two nick 

servos, front and rear.

"4Sv (90°)": Four-point swashplate control affected by 

two roll servos and two nick servos.

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) will set the option back to 

"1 Servo".

Swashplate type: 1 Servo

2

Swashplate type: 2 Servos

2

1

Swashplate type: 3 Servos (2 Roll)

3

1

2

Swashplate type: 3 Servos (140°)

3

1

2
Detail program description - Helicopter type 87

Swashplate type: 3 Servos (2 Nick)

3

2

1

Swashplate type: 4 Servos (90°) 2 Nick / 2 Roll

2

5

1

3

Notice:

Except for the "1 Servo" choice, swashplate mixer 

proportions must also be set in the "Swashplate mixer" 

menu, page 196.

 Swashplate linearizing

After selecting the "Linear. swashpl." line with the 

 arrow keys of the left or right touch pad, the 

corresponding entry fi eld will be framed.

3Sv(2rol)

SEL

Linear. swashpl.

Swashplate

no

Rotor direct right

HELI TYPE

Pitch min. back

The "yes" entry will prevent undesired side effects 

such as pitch change due to a roll function or tension 

between swashplate servo rods.

This type of tension can arise when effected servos 

strain for different displacement positions due to travel 

which deviates from one another.

Linearizing will require a bit of familiarization on 

the part of the pilot because, in order to linearize 

the entire rotation travel for the servo arm, servo 

travel can be appropriately reduced for small control 

movements – similar to a substantial Expo setting – .

 Rotor rotation

After selecting the "Rotor direct" line (rotor direction) 

with the  arrow keys of the left or right touch pad, 

the corresponding entry fi eld will be framed.

3Sv(2rol)

SEL

Linear. swashpl.

Swashplate

no

Rotor direct right

HELI TYPE

Pitch min. back

Once the choice for main rotor rotation direction is made 

with the arrow keys, it is set by pressing the center SET

button in the right touch pad.

"right": The main rotor turns clockwise when viewed 

from above.

"left": The main rotor turns counter-clockwise when 

viewed from above.

Simultaneously pressing the   or  keys of the 

right touch pad (CLEAR) will set the option to "right". 

right-hand

 rotation

left-hand 

rotation

This entry is necessary for correct operational 

orientation of the torque and power compensation mixer 

settings made in the "Helicopter mixer" menu:

 Pitch,

 C1  throttle,

 C1  tail rotor,

 Tail rotor  throttle,

 Roll  throttle,

 Roll  tail rotor,

 Pitch  throttle,

 Nick  throttle,

 Nick  tail rotor.

 Pitch min

After selecting the "Pitch min" (pitch minimum) line with 

the  arrow keys of the left or right touch pad, the 

corresponding entry fi eld will be framed.

3Sv(2rol)

SEL

Linear. swashpl.

Swashplate

no

Rotor direct right

HELI TYPE

Pitch min. back
88 Detail program description - Helicopter type

The "Pitch min" line is used to adapt the direction of 

operation for the throttle/pitch control stick to your 

control preferences. All other helicopter program options 

which involve throttle and pitch functions, e. g. throttle 

curve, idle trimming, tail rotor mixer, etc., are dependent 

on this setting. 

Press the center SET button in the right touch pad. 

The operating direction of the throttle/pitch joystick will 

be displayed in inverse video. Now choose the variant 

needed with the arrow keys of the right touch pad.

Pitch

These mean: 

"fwrd.": minimum pitch setting when the pitch joystick 

(C1) is "forward", i.e. away from the pilot.

"back": minimum pitch setting when the pitch joystick 

(C1) is "back", i.e. toward the pilot.

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) will set this option to "rear".

Notices:

• C1 trimming affects only the throttle servo. 

• The so-called "throttle limiter" is set by default, see text 

beginning page 104, such that the throttle limiter for full 

throttle can be set independently of the pitch servo via 

input "Th.L.12" in the "Control adjust" menu.

• Since your models will typically be operated with the 

same pitch-min direction, this specifi cation can be 

conveniently preselected in the "transmitter-specifi c" 

"Basic Settings" menu, page 224. This specifi cation 

will be adopted automatically when a new model 

memory is created in the "Helicopter type" menu but, 

if desired, can be adapted on a model-specifi c basis 

as described.

 Expo throttle limit

After selecting the "Expo thro lim."line with the 

 arrow keys of the left or right touch pad, the 

corresponding entry fi eld will be framed.

Expo thro lim. 0%

SEL

Linear. swashpl. no

Rotor direct right

HELI TYPE

Pitch min. back

The "Throttle limit" function, described in the text for the 

"Control adjust" menu on page 104, can be assigned 

an exponential characteristic curve.

A pitch progression rate value between -100 % and 

+100 % can be set with the arrow keys.

For example, this is meaningful when the throttle limiter 

is to be regulated in parallel with the idle setting. Further 

details about the throttle limiter can be found in the text 

for the "Control adjust" menu on page 100.

An example of two Expo throttle limit curve characteristics 

for 100 % servo travel.

continuous line:

negative expo values;

dashed line:

positive expo values











 

 

	

 	
Your notes 89
90 Detail program description - Servo adjustment

Column 3 "midpoint"

The servo midpoint setting is intended for adapting a 

non-standard servo (a servo whose midpoint position 

does not correspond to a pulse length of 1.5 ms, i.e. 

1500 μs), as well as for minor adjustments, e. g. for the 

fi ne tuning of the neutral position of model rudders.

Independent of trim levers and any mixer settings, the 

neutral point can be set in a range of -125 % to +125 % 

within a maximum servo travel scope of ±150 %. 

Independent of all other trim and mixer settings, this 

setting is always based directly on the respective servo. 

Note that extreme adjustments of the neutral point can 

lead to one-sided restrictions of servo motion because 

both the electronic and the mechanical aspects limit 

total travel to ±150 %.

Simultaneously pressing the  or  keys in 

the right touch pad (CLEAR) will reset the entry fi eld 

displayed in inverse video back to its "0 %" value.

Column 4 "- Weg +"

This column is used to set servo travel symmetrically or 

asymmetrically for each side. The setting range is 0 ... 

150 % of normal servo travel. The values set are based 

on the settings that have been made for the "midpoint" 

column. 

To create a symmetric

travel path, i. e. controlside independent travel, 

the respective control 

(joystick, proportional 

rotary control or switch) is 

to be put into the position 

which covers travel to 

both sides of the marked 

pad to complete the entry.

6. pressing the Simultaneously  or  keys of 

the right touch pad (CLEAR) will set any setting 

which has been made back to the given default 

value.

Important:

Servo designation numerals are based on the respective 

receiver outputs to which they are connected, provided 

that no swapping of transmitter and/or receiver outputs 

has been specifi ed. This means that even a change of 

stick mode will not effect the numbering of servos.

Column 2 "rev"

The direction in which a servo turns is adapted to the 

practical reality of the given model so that the assembly 

of control rods and joints do not need to accommodate 

a specifi c servo rotation direction. Rotation direction is 

symbolized by the "=>" and "<=" character combinations. 

Servo rotation direction must be specifi ed before making 

settings for the options which follow below.

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) will reset the rotation direction 

to "=>". 

normal

reversed

normal

reversed

This menu is used to set the direction, neutralization, 

travel and limit parameters for a given selected servo 

exclusively. 

Suppress models

Base setup model

Control adjust

Model type

Servo adjustment

Stick mode

Briefl y press the center SET button in the right touch 

pad.

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

Begin setting servo parameters in the left column.

Basic procedure steps:

1. Select the desired servo, S1 ... S12, with the 

arrow keys of the left or right touch pad. 

2. If necessary, use the  arrow keys of the left or 

right touch pad to reach the desired column then, 

if desired, move the respective control out of its 

midpoint to make an asymmetric setting.

3. Briefl y press the center SET button in the right touch 

pad. The respective entry fi eld will be displayed in 

inverse video.

4. arrow keys of the right touch pad to set the Use the 

desired value.

5. Briefl y press the center SET button in the right touch 

 Servo adjustment

Servo direction, midpoint, travel and limit

Servo travel

-125% Centre adjustment +125%
Detail program description - Servo adjustment 91

frame. 

Notice:

It may be necessary to fi rst assign a control to a servo 

attached to one of the 5 ... 12 control channels. If 

necessary, this is to be done in the "Control adjust" 

menu, see page 96 or 100.

To create an asymmetric travel path, the respective 

control (joystick, proportional rotary control or switch) is 

to be moved to the side to be set such that it covers only 

the marked frame.

The value setting is activated by briefl y pressing the 

center SET button in the right touch pad. The value 

fi eld will be displayed in inverse video. Values can be 

changed with the arrow keys of the right touch pad. 

Pressing the center SET button in the right touch pad 

will complete the entry.

Simultaneously pressing the  or  keys in 

the right touch pad (CLEAR) will reset the changed 

parameter in the entry fi eld back to 100 %.

Important:

In contrast to settings made with the "Control adjust"

menu, all settings made in this menu affect exclusively 

the respective servo, independent of how the control 

signal for this servo is produced, i.e. directly by a control 

stick or by way of any mixer functions.

The adjacent fi gure 

shows and example of 

a side-dependent servo 

setting, -50 % and 

+150 %. Transmitter control travel Servo travel

Column 5 "limit"

The "- lim +" column is reached by pushing the marked 

frame with the  arrow key of the left or right touch pad, 

analogous to the pointers at the bottom of the screen, to 

the right beyond the "- trv +" column.

S1

S2

S3

Rev cent lim +

0%

0%

0%

150% 150%

150% 150%

150% 150%

0%

0%

150% 150%

150% 150%

S4

S5

To create a symmetric, i. e. control-side independent 

limit, the respective control (joystick, proportional rotary 

control or switch) is to be put into the position in which 

the marked frame covers both sides of the travel setting.

To set asymmetric travel, the respective control (joystick, 

proportional rotary control or switch) is to be moved to 

the side on which the marked frame only includes the 

value to be changed.

Simultaneously pressing the  or  keys in 

the right touch pad (CLEAR) will reset the entry fi eld 

displayed in inverse video back to its "0 %" value.

Example:

A servo is controlled separately by two controls over a 

mixer and but, for model-specifi c reasons, must only be 

operated over a servo travel path of 100 % because, for 

example, the rudder would mechanically collide with the 

elevator if moved more than 100 %.

As long as only one control is used at a time, this is 

no problem. But this does become a problem when 

the signals of both controls (e. g. aileron and rudder) 

combine to form an overall travel in excess of 100 %. 

The linkage and servos could be strained excessively ...

To prevent this, the travel should certainly be limited by 

way of an individual travel limit. In the case of the rudder 

used in the example, this would be a value slightly less 

than 100 % – because it is assumed the rudder would 

collide at 100 % – .
92 Detail program description - Joystick setting

Both joysticks are equipped for digital trimming. With 

each brief push (one "click") on a joystick it will change 

its neutral position by one increment. Holding the stick 

longer will cause trimming to run in the corresponding 

direction at increasing speed. 

The current position is shown on the screen and 

adjustment is also made "audible" by various high 

frequency tones. This makes fi nding the mid-point during 

fl ight easy, without looking at the screen. If the mid-point 

is overrun, a brief motion pause will be inserted.

Current trim values are automatically stored when a 

model memory change is made.

Furthermore – except for trimming the throttle/brake 

joystick, commonly referred to as control function "C1" 

(channel 1) – digital trimming is effective within a model 

memory location selectively as either a global parameter 

(i. e. consistent in all fl ight phases) or as a fl ight-phase 

specifi c parameter. This specifi cation as "global" 

or "phase" is made in the "Joystick setting" menu 

described here, whereas C1 trimming is always made 

"globally", i. e. independent of fl ight phases.

This setting is visualized in the base screen by a 

"shadow" on trim bars:

• shadow present = global,

• no shadow = fl ight phase dependent.

The following fi gure shows elevator trim – in the right 

column with standard Mode 1 – as being fl ight-phase 

dependent.

 Joystick setting

Setting stick mode 1 through 4

GRAUBELE

#01

2:22h

Stop

Flt

«Normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

Scroll with the arrow keys of the left or right touch pad to 

the "Stick mode" menu item of the multifunction menu. 

Servo adjustment

Dual Rate / Expo

Stick mode

Channel 1 curve

Switch display

Control adjust

Open this menu item by pressing the center SET button 

in the right touch pad.

Ch.1

Aile

Elev

Tr time +

4

4

4

0.0s

0.0s

0.0s

Rudd 4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

GL

St

This menu, adapted for winged models, permits the trim 

effects of the four digital trim levers to be established 

and control functions 1 through 4 to be selectively 

"decelerated".

The desired line can be reached by using the arrow 

keys of the left or right touch pad. Once the appropriate 

function fi eld has been selected and then the center 

SET button in the right touch pad is pressed briefl y, the 

fi eld will appear in inverse video and the desired setting 

can be made with the arrow keys of the right touch pad.

Column "Tr" (trim)

Except for "channel 1", this column can be used to 

switchover trim effect from "GL(obal)" to "PH(ase)" and 

vice versa. For example: 

Tr +

4

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

St

PH

Ch.1

Aile

Elev

time

Rudd

"GL": The position of the respective trim lever 

is effective for the given model "globally", 

i.e. across any fl ight phases which may be 

programmed for it, page126.

"PH": The position of the respective trim lever is 

effective on a phase-specifi c basis and will 

be automatically stored upon change of fl ight 

phase so that the setting is again available 

following a return to this fl ight phase.

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) switches the entry back to 

"GL".

Column "St" (trim steps)

The four digital trim levers push the neutral point of the 

respective joystick by one increment for each press 

("click"). This is where the increment size (step) can be 

adjusted for a given direction, whereby maximum trim 

travel, independent of the selected number of trim steps, 

is always about ±30 % of control travel.

After selecting column "St" (Steps) and then the desired 

trim control with the  arrow keys of the left or right 
Detail program description - Joystick setting 93

touch pad, the corresponding entry fi eld will be framed. 

For example:

Tr +

4

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

GL

St

Ch.1

Aile

Elev

time

Rudd

Briefl y press the center SET button in the right touch 

pad. The current setting will be displayed in inverse 

video. Now select the desired value, between 1 and 10, 

with the arrow keys of the right touch pad. For example:

Tr +

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

GL

St

8

Ch.1

Aile

Elev

time

Rudd

Simultaneously pressing the  or  arrow keys of 

the right touch pad (CLEAR) will reset the change made 

in the active fi eld back to "4".

Column "time"

The "time" column entries infl uence joystick acceleration 

speed/s – if applicable, for each movement direction 

for the four control sticks, 1 through 4, separately – . 

This means that respective servos will then follow rapid 

control position changes only at an accordingly delayed 

rate. This time delay has a direct effect on the control 

function and therefore also any servos controlled by this 

function.

The time can be programmed symmetrically for both 

sides or separate for each control direction. This setting 

has a programmable range of 0 s to 9.9 s. In the case of 

side-separate settings, the joystick is to be moved to the 

respective side so that the inverse video fi eld will switch 

between sides to the one for which the change is to be 

made, – for example, even to ensure gentle rev-up of 

the propulsion motor despite a (too) fast motion of the 

C1 stick.

Tr +

4

4

4

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

GL

St

Ch.1 1.1s

Aile

Elev

time

Rudd

On the other hand, for reasons of safety, the motor cutoff should always be "immediate".

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) will reset the change made to 

the active fi eld back to "0.0 s".
94 Detail program description - Joystick setting | Helicopter model

Both joysticks are equipped for digital trimming. With 

each brief push (one "click") on a joystick it will change 

its neutral position by one increment. Holding the stick 

longer will cause trimming to run in the corresponding 

direction at increasing speed. 

The current position is shown on the screen and 

adjustment is also made "audible" by various high 

frequency tones. This makes fi nding the mid-point during 

fl ight easy, without looking at the screen. If the mid-point 

is overrun, a brief motion pause will be inserted.

Current trim values are automatically stored when a 

model memory change is made. 

Furthermore – except for trimming the throttle/brake 

joystick – digital trimming is effective selectively either as 

a global parameter, i. e. consistent in all fl ight phases, or 

as a fl ight-phase specifi c parameter. This specifi cation 

as "global" or "phase" is made in the "Joystick setting" 

menu described here, whereas throttle trimming is 

always made "global" by software, i. e. independent of 

fl ight phases.

This setting is visualized in the base screen by a 

"shadow" on trim bars:

• shadow present = global,

• no shadow = fl ight phase dependent.

In the following fi gure nick trimming is used as an 

example of fl ight-phase dependence – presented in its 

default Mode 1 at the left – .

STARLET

#02

2:22h

Stop

Flt

«Normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

 Joystick setting

Setting stick mode 1 through 4

Scroll with the arrow keys of the left or right touch pad to 

the " Stick mode " menu item of the multifunction menu. 

Suppress models

Model select

Base setup model

Model type

Copy / Erase

Suppress menus

Open this menu item by pressing the center SET button 

in the right touch pad.

Model select

Base setup model

Model type

Copy / Erase

Suppress models

Suppress: TOG

This menu, adapted for helicopter models, permits 

the trim effects of the four digital trim levers to be 

established and control functions 1 through 4 to be 

selectively "decelerated".

The desired line can be reached by using the arrow 

keys of the left or right touch pad. Once the appropriate 

function fi eld has been selected and then the center 

SET button in the right touch pad is pressed briefl y, the 

fi eld will appear in inverse video and the desired setting 

can be made with the arrow keys of the right touch pad.

Column "Tr" (trim)

These setting variations are confi gured to accommodate 

the needs of helicopter models, which is why the following 

alternative options are available for the "Thr." line:

Tr +

4

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

St

PH

Ch.1

Aile

Elev

time

Rudd

"TL": "throttle limit"

 C1 trimming operates as idle trimming when 

the "throttle limit" function regulates the motor 

for starting, see "Control adjust" menu, 

page 104.

"AR": "autorotation throttle"

 C1 trim operates as idle trim exclusively in the 

"Autorot" fl ight phase.

 This makes it possible to assign a principle 

(fi xed) preset AR throttle position in the 

"Helicopter mixer" menu, page 164, e. g. for 

use during autorotation practice, which can be 

"varied" with the idle trim lever.

 Simultaneously pressing the  or 

keys of the right touch pad (CLEAR) will 

switch this option back to "TL".

On the other hand, the trim effects of respective digital 

trimming controls for the lines "Roll", "Nick" and "Tail 

rotor" can be switched over from "GL" to "PH" and vice 

versa. Example:

Tr +

4

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

St

PH

Thr.

Roll

Nick

time

Tail

TL
Detail program description - Joystick setting | Helicopter model 95

"GL": The position of the respective trim lever 

is effective for the given model "globally", 

i.e. across any fl ight phases which may be 

programmed for it, page 126.

"PH": The position of the respective trim lever is 

effective on a phase-specifi c basis and will 

be automatically stored upon change of fl ight 

phase so that the setting is again available 

following a return to this fl ight phase.

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) will switch the entry back to 

"GL".

Column "St" (trim steps)

The four digital trim levers push the neutral point of the 

respective joystick by one increment for each press 

("click"). This is where the increment size (step) can be 

adjusted for a given direction, whereby maximum trim 

travel, independent of the selected number of trim steps, 

is always about ±30 % of control travel.

After selecting column "St" (Steps) and then the desired 

trim control with the  arrow keys of the left or right 

touch pad, the corresponding entry fi eld will be framed. 

Example:

Tr +

4

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

PH

St

Thr.

Roll

Nick

time

Tail

TL

Briefl y press the center SET button in the right touch 

pad. The current setting will be displayed in inverse 

video. Now select the desired value, between 1 and 10, 

with the arrow keys of the right touch pad. For example:

Tr +

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

PH

St

8

Thr.

Roll

Nick

time

Tail

TL

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) will reset any change made to 

the active fi eld back to "4".

Column "time"

The "time" column entries infl uence joystick acceleration 

speed/s – if applicable, for each movement direction 

for the four control sticks, 1 through 4, separately – . 

This means that respective servos will then follow rapid 

control position changes only at an accordingly delayed 

rate. This time delay has a direct effect on the control 

signal and therefore also commensurately on any servos 

controlled by the effected controls.

The time can be programmed symmetrically for both 

sides or separate for each control direction. This setting 

has a programmable range of 0 s to 9.9 s. In this latter 

case, the given stick control is to be moved to the 

respective side so that the inverse video fi eld will switch 

between sides to the one for which the change is to be 

made. 

Example:

All three servos are to be actuated for swashplate 

pitch control, e g. a "Pitch" control movement for a "3Sv 

(2Roll)" swashplate. However, travel for the middle 

servo is greater than that of the other two servos on the 

shorter lever.

A rash "Pitch" control movement would not operate 

the nick servo in the middle as quickly as it would the 

two roll servos on the shorter lever. This would cause 

a momentary control motion in the "nick" direction. 

However, if response time for the "pitch" control function 

were to be reduced by at least the positioning time for 

the servo in the middle then all three servos would reach 

their proper positions at the same time. The necessary 

delay times typically amount to only a few tenths of a 

second. For example:

Tr +

4

4

8

0.0s

4 0.0s

0.0s

0.0s

0.0s

TA

GL

GL

PH

St

0.0s

Thr. 0.2s 0.2s

Roll

Nick

time

Tail

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) will reset any change made to 

the active fi eld back to "0.0 s".
96 Detail program description - Control adjust

 Control adjust

Fundamental operating steps for control and switch assignments

Servo adjustment

Dual Rate / Expo

Stick mode

Channel 1 curve

Switch display

Control adjust

Briefl y press the center SET button in the right touch 

pad.

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

normal

Aside from the two joysticks which operate control 

functions 1 through 4, a standard mx-20 HoTT 

transmitter is also equipped with other operating 

elements:

• two 3 position switches: SW 4/5 or CTRL 9 and SW 

6/7 or CTRL 10. These are assigned in this menu as 

"Ct9" and "C10".

• three proportional rotary controls: CTRL 6, 7 and 8. 

Respectively designated "Ct6", "Ct7" and "Ct8" in the 

menu.

• three 2 position switches: SW 2, 3 and 8. 

Respectively displayed in the menu as "2", "3" and 

"8" in combination with a switch symbol indicating the 

switching direction.

• two pushbutton switches: SW 1 and SW 9. Analogous 

to the aforementioned switches; designated as "1" 

and "9" and displayed in combination with a symbol 

indicating switching direction.

In contrast to the two joysticks which, when initialized 

for a new model memory as a "Winged aircraft" model 

type will already be confi gured to operate the servos 

connected to receiver outputs 1 ... 4, these "other" 

operating elements initially remain inactive. 

Thus, at least in the system's delivered state, – as 

already mentioned on page 20 – or even after the 

initialization of a new model memory with the "Winged 

aircraft" model type and its "binding" to the intended 

receiver, only those servos connected to the two 

joysticks by way of receiver outputs 1 ... 4 are able to 

be operated; any servos which may be connected to the 

receiver's outputs 5 ... 12 will initially remain inactive in 

their middle positions.

Even though this may seem inconvenient at fi rst glance, 

it is indeed just this state which offers full freedom to 

select and assign these "other" operating elements as 

desired and leaves any unused operating elements 

harmlessly dormant without taking any action to 

deactivate them. This has the advantage that: 

An unused operating element will have no infl uence 

on your model's operation even if inadvertently 

operated; it will be inactive and therefore have no 

assigned function.

These "other" operating elements can be freely 

assigned to meet your needs and the features of your 

model. They can be assigned to any function input in 

the "Control adjust" menu, see page 50. But this also 

means that each of these operating elements can also 

be assigned to multiple functions at the same time. 

For example, one and the same toggle switch, SW 

X, assigned in this menu to an input, can at the same 

time be assigned to a "timer" as an On/Off switch in the 

"Timers (general)" menu...

Furthermore, all inputs can be selectively made global

or fl ight-phase specifi c (providing that fl ight phases have 

been defi ned in the menus "Phase settings", page 128, 

and "Phase assignment", page 134). The respective 

names for the given fl ight phases will then appear in the 

bottom screen line, e. g. "normal". 

Basic procedure steps

1. Select the desired input, E5 ... 12 with the  arrow 

keys of the left or right touch pad. 

2. If necessary, use the  arrow keys of the left or 

right touch pad to change to the desired column.

3. press the center Briefl y SET button in the right touch 

pad. The respective entry fi eld will be displayed in 

inverse video.

4. Actuate the desired operating element or use the 

arrow keys of the right touch pad to set the desired 

value.

5. press the center Briefl y SET button in the right touch 

pad to complete the entry.

6. pressing the Simultaneously  or  arrow 

keys of the right touch pad (CLEAR) will reset any 

setting change back to its default value.
Detail program description - Control adjust 97

 Column 2 "typ"

Analogous to the "Stick mode" menu already described, 

this column can be used to select whether other settings 

are to be made for the given input, e. g. "GL(obal)" or 

"PH(ase specifi c)" and vice versa. 

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

normal

"GL": The given input's settings will be "globally" 

effective for the respective model memory 

across any fl ight phases which may be 

programmed.

"PH": The settings for this input will be effective on 

a fl ight-phase basis and must therefore be 

explicitly set in each fl ight-phase where it is to 

be effective.

Notice:

More about fl ight phases on page 126.

 Column 3 "Control or switch assignment"

Use the  arrow keys of the left or right touch pad to 

select one of the inputs, 5 through 12. 

Briefl y press the center SET button in the right touch 

pad to activate the assignment.

Input 5

offset

0%

0%

0%

–––

0%

Eing. 6

Eing. 7

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

Move desired switch

or control adj.

Normal

Now activate the desired control (CTRL 6 through 10) 

or selected switch (SW 1 through 3, or 8 or 9) - whereby 

a proportional rotary control will only be detected after 

some "detenting" action has taken place and so may 

have to be activated a bit longer. If adjustment travel is 

insuffi cient, activate the control in the other direction. 

Two position switches can only switch back and forth 

between their fi xed end states, e. g. motor ON or OFF. 

On the other hand, the 3 position switches, SW 4/5 or 

6/7, that can be incorporated in this "Control adjust"

menu as "Ct9" or "C10", also offer a middle position.

Simultaneously pressing the  or  keys of the 

right touch pad (CLEAR) for an active control or switch 

assignment – see fi gure above – will reset the input back 

to its "free" state.

Tips:

• When assigning switches, pay attention to the 

desired switching direction and also that all unused 

inputs remain "free" or are again reset to "free" (if 

applicable, across all fl ight phases). This is necessary 

to ensure that inadvertent actuations of these unused 

controls cannot cause malfunctions.

• The travel setting described below allows the 

appropriate end state to be established for an 

assigned switch.

For example, the screen will now show either the 

control's number or – in conjunction with a switch 

symbol indicating the switching direction – the switch's 

number .

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

GL

GL

GL

GL

typ

Ct6

3

Normal

 Column 4 "offset"

The control midpoint for the given control, i. e. its zero 

point, can be changed in this column. The adjustment 

range lies between -125 % and +125 %.

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

GL

GL

GL

GL

typ

Ct6

3

Normal

Simultaneously pressing the  or  keys in 

the right touch pad (CLEAR) will reset the entry fi eld 

displayed in inverse video back to "0 %".

 Column 5 "-travel+"

This column is used to set servo travel symmetrically or 

asymmetrically for each side. The setting range is ±125 % 

of normal servo travel.

Use the  arrow keys of the left or right touch pad to 

select one of the inputs, 5 through 12.

To set symmetric travel, i. e. control-side independent 

travel, the respective operating element (proportional 

rotary control or switch) is to be put into a position which 
98 Detail program description - Control adjust

covers travel to both sides of the marked frame.

Input 5

–travel+

+100%

+100%

+100%

+100%

Input 6

Input 7

Input 8

+100%

+100%

+100%

+100%

Normal

To set asymmetric travel, the respective control 

(proportional rotary control or switch) is to be moved to 

the side on which the marked frame only includes the 

value to be changed.

Input 5

–travel+

+100%

+100%

+100%

+100%

Input 6

Input 7

Input 8

+100%

+100%

+100%

+100%

Normal

The value setting is activated by briefl y pressing the 

center SET button in the right touch pad. The value 

fi eld will be displayed in inverse video. Values can be 

changed with the arrow keys of the right touch pad.

Input 5

–travel+

+100%

+100%

+100%

Input 6

Input 7

Input 8

+100%

+100%

+100%

+111% +111%

Normal

Input 5

–travel+

+100%

+100%

+100%

Input 6

Input 7

Input 8

+100%

+100%

+100%

+111% +88%

Normal

Another brief press of the center SET button in the right 

touch pad will complete the entry.

Negative and positive parameter values are possible in 

order to appropriately adapt the control's direction or 

effect.

Simultaneously pressing the  or  keys in 

the right touch pad (CLEAR) will reset the changes 

parameter in the inverse video entry fi eld back to 

+100 %.

Important:

In contrast to the servo travel setting, control travel 

setting effects all derived mixer and coupling functions, 

i. e. infl uences all servos which can be actuated by way 

of the respective control.

 Column 6 "time"

A symmetric or asymmetric time delay between 0 and 

9.9 s can be applied to each of the 5 ... 12 function 

inputs.

Use the  arrow keys in the left or right touch pad to 

push the marker frame to the right, beyond the "-travel+" 

column.

To set a symmetric, (i. e. control-side independent) time 

delay, the respective operating element (proportional 

rotary control or switch) must be put into a position 

which covers time to both sides of the marked frame.

Input 5

– time +

0.0

0.0

0.0

0.0

Input 6

Input 7

Input 8

0.0

0.0

0.0

0.0

Normal

To set an asymmetric time delay, the respective control 

(proportional rotary control or switch) is to be moved to 

the side on which the marked frame only includes the 

value to be changed.

Input 5

– time +

0.0

0.0

0.0

0.0

Input 6

Input 7

Input 8

0.0

0.0

0.0

0.0

Normal

Notice:

Further suggestions for structuring timed fl ows can be 

found in the section "Control of timed fl ows" on page 266.
Detail program description - Control adjust 99
100 Detail program description - Control adjust

 Control adjust

Basic procedure for transmitter control and switch assignment

Servo adjustment

Dual Rate / Expo

Stick mode

Channel 1 curve

Switch display

Control adjust

Briefl y tap the center SET key on the right touch pad:

Input 5

offset

0%

0%

0%

Throt

Gyro

Input 8 –––

–––

6 –––

7

Input 9

Input10

Input11

Th.L.12

–––

–––

–––

Ct6

0%

0%

0%

0%

GL ––– 0%

GL

GL

GL

GL

GL

GL

GL

typ

In addition to the two dual axis sticks for control 

functions 1 to 4, the mx-20 HoTT transmitter is 

equipped with other controls as standard:

• Two 3-stage switches: SW 4/5 and CTRL 9, plus SW 

6/7 and CTRL 10. On this menu, these are assigned 

as "Ct9" and "Ct10".

• Three proportional rotary controls: CTRL 6, 7 and 8. 

Named as "Ct6", "Ct7" and "Ct8" on this menu.

• Three 2-stage switches: SW 2, 3 and 8. Labeled 

accordingly as "2", "3" and "8" on the menu. A switch 

icon indicating the switch direction is also shown.

• Two push-button switches: SW 1 and SW 9. 

Displayed as with the preceding switches, "1" and "9" 

with a switch icon indicating the switch direction.

Even with a newly-initialized model memory for the 

"Helicopter" model type, the two dual axis sticks will – in 

the absence of further confi guration – infl uence only 

those servos connected to receiver outputs 1 ... 4 and 

6. Unlike these, the "additional" transmitter controls 

mentioned above are theoretically inactive at fi rst. (The 

exception here is the CTRL 6 proportional rotary control 

(throttle limiter), which also affects servo 6.) 

One of the effects of this is that (as mentioned back 

on page 20 ) with a factory-fresh unit, only the servos 

connected to receiver outputs 1 ... 4 and –depending on 

the position of the throttle limiter– servo 6 can be moved 

using the two joysticks. (This also applies following 

the initialization of a new model memory with the 

"Helicopter" model type and its "binding" to the receivers 

to be installed in the model.) The servos connected 

to slots 5, 7 and 8, on the other hand, will simply stay 

"stuck" at their center points.

While this may appear more than a little awkward at 

fi rst glance ... this is the only way to ensure that you 

can select any of the "additional" transmitter controls 

as you wish and, in addition, do not need to waste time 

"disabling" control elements you do not require. This is 

because 

the only way to ensure an unwanted control element 

has no effect on your model, even if operated by 

accident, is to make it inactive, i.e. unassigned to a 

function.

You can therefore use this "Control adjust" menu 

exactly as you wish, to assign the "additional" control 

elements as you want to any required function input; for 

further details, see page 50. Equally, this also means 

that you can assign individual transmitter controls to 

multiple functions at the same time, if required. As an 

example: the exact same rocker switch SW X that you 

assign to an input on this menu can simultaneously be 

assigned to "Timers" on the "Timers (general)" menu 

as an "On/Off" switch, etc.

Note:

As a rule, input 6 must kept "free" for a helicopter model. 

On this, see "Throttle" on the next double page.

Furthermore, if fl ight phases have been defi ned on 

the "Phase settings" menu (page 128) and "Phase 

assignment" menu (page 134), then all inputs must be 

set either as global or fl ight phase-specifi c. The names 

assigned to each of these fl ight phases are then shown 

in the bottom line of the screen display, e. g. "Normal".

Basic procedure

1. Using the arrow keys  on the left or right touch 

pad, select the input you want: Input 5, Throt 6, Gyro 

7, Input 8 ... 11 or Th.L.12. 

2. If necessary, use the arrow keys  on the left or 

right touch pad to select the column you want.

3. Briefl y tap the center SET key on the right touch pad. 

The corresponding input fi eld is shown highlighted.

4. the Activate your chosen transmitter control or use 

arrow keys on the right touch pad to set your chosen 

value.

5. Briefl y tap the center SET key on the right touch pad 

to complete data entry.

6. tap the If you  or  keys on the right touch 

pad at the same time (CLEAR), this will reset any 

settings made back to their respective default values.

 Column 2, "typ"

Similarly to the "Stick mode" menu described 

previously, this column can be used to defi ne whether 

further settings for the input in question are to have a 
Detail program description - Control adjust 101

 Column 4, "offset"

In this column, you change the control center, i. e. the 

zero point, for the transmitter control in question. The 

adjustment range lies between -125 % and +125 %.

Input 5

offset

0%

0%

0%

–––

0%

Throt

Gyro

Input 8

–––

GL

GL

GL

GL

typ

Normal

6

7 Ct7

3

If you tap the  or  keys on the right touch pad 

(CLEAR) at the same time, this will reset the value in 

the highlighted fi eld back to 0%.

 Column 5, "–travel+"

This column is used to set servo travel symmetrically or 

asymmetrically for each side. The setting range is ± 125 % 

of normal servo travel.

Using the arrow keys  on the left or right touch pad, 

select an input: Input 5, Throt 6, Gyro 7, Input 8 ... 11 or 

Th.L.12.

To confi gure symmetrical travel, i. e. one independent of 

the control side, move the affected transmitter control 

(proportional rotary control or switch) to a position at 

which the marker frame encloses both sides of the travel 

adjustment region:

–travel+

+100%

+100%

+100%

+100%

+100%

+100%

+100%

+100%

Normal

Input 5

Throt

Gyro

Input 8

6

7

"GL(obal)" or a "PH(ase-specifi c)" effect, as follows: 

Input 5

offset

0%

0%

0%

–––

0%

Throt

Gyro

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

Normal

6

7

"GL": The settings for the input in question affect all 

fl ight phases programmed (if any) and thus act 

"globally" on the model memory in question.

"PH": The settings for this input take effect per 

fl ight phase and must therefore be confi gured 

separately for each fl ight phase.

Note:

See page 128 for more information on fl ight phases.

 Column 3, "Transmitter control/switch assignment"

Using the arrow keys  on the left or right touch pad, 

select an input: Input 5, Throt 6, Gyro 7, Input 8 ... 11 or 

Th.L.12.

Briefl y tap the center SET key on the right touch pad to 

activate the assignment option:

Input 5

offset

0%

0%

0%

–––

0%

Gas

Gyro

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

Normal

6

7

Move desired switch

or control adj.

Now move your chosen transmitter control (CTRL 6 

to 10) or selected switch (SW 1 to 3, 8 and 9). Note, 

however, that the proportional rotary controls are only 

identifi ed after a few "turns": this means you need to 

move them for slightly longer. If the control does not 

have enough travel, move the control in the opposite 

direction as required. 

Once assigned, the 2-stage switches can be switched 

back and forth only between their respective endpoints, e. g. headlights ON/OFF. In contrast, the 3-stage 

switches SW 4/5 and 6/7 also permit a center control 

position; these are confi gured as "Ct9" or "Ct10" on the 

"Control adjust" menu.

If a switch has been assigned, then tapping the 

or  keys on the right touch pad at the same time 

(CLEAR) bei aktivierter Schalterzuordnung – see screen 

image above – will reset the input back to "free".

Tips:

• When assigning switches, pay attention to the 

desired switching direction and also that all unused 

inputs remain "free" or are again reset to "free" (if 

applicable, across all fl ight phases). This is necessary 

to ensure that inadvertent actuations of these unused 

controls cannot cause malfunctions.

• The travel setting described below allows the 

appropriate end state to be established for an 

assigned switch.

The screen now shows either the control number 

or – alongside a switch icon that shows the switch 

direction – the switch number, e. g.:

Input 5

offset

0%

0%

0%

–––

0%

Throt

Gyro

Input 8

–––

GL

GL

GL

GL

typ

Normal

6

7 Ct7

3
102 Detail program description - Control adjust

To confi gure asymmetric travel, move the affected 

transmitter control (proportional rotary control or switch) 

to the side on which you wish to confi gure it, so the 

marker frame encloses only the value you want to adjust:

–travel+

+100%

+100%

+100%

+100%

+100%

+100%

+100%

+100%

Normal

Input 5

Throt

Gyro

Input 8

6

7

Briefl y tap the center SET key on the right touch pad 

to activate value confi guration: The value fi eld is shown 

highlighted. Use the arrow keys on the right touch pad to 

change the values:

–travel+

+100%

+100%

+100%

+100%

+100%

+100%

+111% +111%

Normal

Input 5

Throt

Gyro

Input 8

6

7

–travel+

+100%

+100%

+100%

+100%

+100%

+100%

+111% +88%

Normal

Input 5

Throt

Gyro

Input 8

6

7

Complete the confi guration by tapping the center SET

key on the right touch pad.

Negative and positive parameter values are possible in 

order to appropriately adapt the control's direction or 

effect.

If you tap the  or  keys on the right touch pad 

(CLEAR) at the same time, this will reset parameters 

changed in the highlighted fi eld back to +100%.

Important:

In contrast to altering servo travel, changing the control 

travel setting affects all "downstream" mixer and 

coupling inputs, i. e. any and all servos that could be 

actuated by the transmitter controls concerned.

 Column 6, "– time +"

Each of the function inputs 5 ... 12 can be assigned a 

symmetrical or asymmetric time delay of between 0 and 

9.9. s.

Using the arrow key  on the left or right touch pad, 

move the marker frame over the "– travel +" column and 

to the right.

To confi gure a symmetrical time delay, i. e. one 

independent of the control side, move the affected 

transmitter control (proportional rotary control or switch) 

as necessary to a position at which the marker frame 

encloses both sides of the time adjustment region:

– time +

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Normal

Input 5

Throt

Gyro

Input 8

6

7

To confi gure an asymmetric time delay, move the 

affected transmitter control (proportional rotary control 

or switch) as required to the side on which you wish 

to confi gure it, so the marker frame encloses only the 

value you want to adjust:

– time +

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Normal

Input 5

Throt

Gyro

Input 8

6

7

Note:

Other suggestions for designing timed sequences 

can be found under "Controlling timed sequences" on 

page 266.
Detail program description - Control adjust 103

 "Throt 6"

Input 5

offset

0%

0%

0%

–––

0%

Throt

Gyro

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

Normal

6

7

In the helicopter program, it is also theoretically possible 

to assign any transmitter control (rotary proportional 

controls and switches) to individual inputs.

However, please note here that some of the inputs 

available on this menu are already assigned to 

helicopter-specifi c functions, and therefore cannot be 

re-assigned in this way.

If we consult the receiver assignment table on page 59, 

for example, we see that the throttle servo (or speed 

controller of an electrically-powered helicopter) must be 

connected to receiver output "6", since control channel 

"6" is reserved for motor power control. 

Unlike a fi xed-wing model aircraft, however, the throttle 

servo or speed controller is not directly controlled by 

the throttle stick or other transmitter control, but by a 

complex mixer system – see the "Helicopter mixers"

menu (from page 164). Furthermore, the "Throttle limit 

function" described on the next page also infl uences this 

mixer system.

Assigning a transmitter control or switch on the 

"Throttle" line, or to its supplementary control signal, 

would unnecessarily "confuse" this complex mixer 

system. For this reason the "Throttle" input MUST be 

left "free".

 " Gyro 7"

Input 5

offset

0%

0%

0%

–––

0%

Throt

Gyro

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

Normal

6

7

Most of the latest gyro systems not only feature infi nitely 

variable proportional gyro gain setting, but also offer 

a choice of two separate types of gain mode on the 

transmitter. 

If the gyro you are using also has this feature, then 

this menu option gives you the opportunity to specify 

both "normal" gyro gain and, as appropriate, to specify 

"heading-lock mode" in the "Offset" column in the 

range of ±125%, plus a particular gain type within this 

pre-selection, so as to be able to exploit maximum 

stabilization for normal, slow fl ight, but to reduce gyro 

gain for fast circuits and aerobatics.

To proceed as described above, use fl ight phase 

switching to enter different settings on the "Gyro" line.

From the starting-point of these 

predefi ned – static – fl ight phase-specifi c settings, you 

can then use a transmitter control assigned to the "Gyro 

7" line, e. g. one of the rotary potentiometers CTRL 7 

or 8, to vary the gyro gain around the respective "offset 

point": The center point of the control corresponds to 

the setting specifi ed by the offset. If the transmitter 

control is moved from this center point in the direction 

of full travel, gyro gain increases proportionally; it 

diminishes when moved in the opposite direction. This 

provides a fast and straightforward method of adjusting 

gyro gain even in flight – e. g. to suit changing weather 

conditions – or to test-fl y optimum settings. In software 

terms you can even limit the gyro gain range in both 

directions by adjusting transmitter control travel. 

In this context, ensure that you comply with the 

instructions on adjusting your gyro: if not, you 

risk making adjustments that render your heli 

impossible to fl y.

 Adjusting the gyro sensor

To achieve the maximum possible level of stabilization 

for the helicopter with the gyro along the vertical axis, 

observe the following:

• The controls should have as little friction and "play" 

as possible.

• There should be no "spring" in the control linkage.

• Use a strong and – in particular – a fast servo. 

When the gyro sensor detects a model rotation, the 

faster its response – a corresponding corrective change 

to tail rotor thrust – takes effect, the further the gyro 

gain adjustor can be moved without causing the tail of 

the model to start oscillating, and the better the model's 

stability about its vertical axis. If the response is slower, 

there is a risk that the model's tail will start to oscillate 

even at low gyro gain settings. Here, further reductions 

to gyro gain will need to be made – either by using the 

default value under "Gyro" or the associated transmitter 

control – to eliminate the oscillation.

If the model is fl ying forward at high speed or hovering 

in a powerful headwind, the net result of the stabilizing 

effect of the vertical fi n combined with the gyro may 

also lead to an overreaction that once again manifests 

itself through tail oscillation. To achieve optimum gyro 

stabilization under all conditions, you should make use 

of the option to adjust gyro gain from the transmitter 
104 Detail program description - Control adjust

control using either the CTRL 7 or 8 proportional rotary 

control.

"Thr.l 12"

As standard, the "Thr.l 12" input is assigned to the CTRL 

6 proportional rotary control mounted on the top left of 

the transmitter.

Input 9

offset

0%

0%

0%

–––

0%

Input

Input

Th.L.12 Ct6

–––

–––

GL

GL

GL

GL

typ

Normal

10

11

This pre-assignment makes it unnecessary to program 

the two fl ight phases that may be familiar to you from 

using other remote control systems – namely "with 

idle-up" and "without idle-up"" – ,since the mx-20

HoTT program offers a much more fl exible approach to 

fi ne-tuning and optimizing increases to system rotational 

speed below the hover point than "idle-up". If you 

nonetheless prefer to program your helicopter "with idleup", then deactivate the "throttle limit" function described 

below by setting input "Thr.l 12" to "free".

 Meaning and application of "throttle limit"

As already mentioned under "Throttle", and in contrast 

to fi xed-wing models, the power output of a helicopter's 

drive system is not controlled directly using the C1 

joystick, but only indirectly via the throttle curve settings 

on the "Helicopter mixers" menu or – if your model 

features a speed governor – by using this mechanism.

Note:

For separate fl ight phases, you can of course use fl ight 

phase programming to set specifi c throttle curves. 

Nevertheless, both methods of output control de facto 

result in the helicopter carburetor never approaching 

 Throttle limit function

anything near its idle speed under "normal" fl ight 

conditions, and that the motor can therefore neither be 

started or stopped cleanly without some other means of 

intervention. 

The "throttle limit" feature resolves this problem 

elegantly by using a separate transmitter control – by 

default the CTRL 6 proportional control mounted on the 

top left of the transmitter – to limit the throttle servo or 

the output level of the speed controller. In this way, it is 

possible to use the throttle limit control to "throttle back" 

as you wish as far as the idle setting – at which point 

the trim lever on the throttle/collective pitch stick takes 

over – or to cut out an electrical drive system directly. 

Conversely, the throttle servo or speed controller can 

only open up to its full-throttle position if the throttle limit 

control has also released the full servo travel path.

The value set on the (right-hand) plus side of the "travel" 

column must therefore always be set to high enough 

to ensure that the maximum setting of the throttle limit 

control never restricts the full-throttle position that can 

be obtained using throttle curve settings – which typically 

means setting a value in the range +100% to 125%. 

–travel+

+100%

+100%

+100%

+100%

+100%

+100%

+100%

Normal

Input 9

Input10

Input

Th.L.12 +125%

11

The value on the (left-hand) minus side of the "travel" 

column should be set so that the throttle limit control 

can be used to safely cut out an electrical drive system 

or close a carburetor down far enough that the glow 

motor can also be cut out in conjunction with the 
Detail program description - Control adjust 105

the – digital – C1 trim. You should thus (initially) leave this 

value at +100%.

Furthermore, this variable "limiting" of throttle travel not 

only gives you a convenient method for starting and 

stopping the motor, but may also prove to have added 

a not inconsiderable increase in safety! For example, 

just imagine what could happen if you were carrying the 

helicopter to the take-off site with the motor running and 

you accidentally moved the C1 stick ... 

Accordingly, if the carburetor or speed controller is open 

too far, an audible warning is heard as soon as you turn 

on the transmitter, and the message below is shown on 

the basic display:

Throttle

too

high !

Tip:

You can use the "Servo display" menu to observe 

the infl uence of the throttle limit slider. This menu 

can be accessed from almost any other menu by 

simultaneously pressing the  keys on the left touch 

pad. Bear in mind that servo output 6 controls the 

throttle servo on the mx-20 HoTT!

 Basic idle setting

Start by turning the throttle limiter – by default the 

CTRL 6 proportional rotary control on the top left of the 

transmitter – clockwise as far as it will go. Set the throttle/

collective pitch stick to the maximum pitch position and 

also check the submenu "C1  Thr" on the menu ...

"Helicopter mixers" (pages 164 ... 179)

... to ensure you have an active standard throttle curve. 

If, for example, the standard throttle curve has already 

been changed following the initialization of a model 

memory, then this must be reset at least temporarily to 

the values "Point 1 = -100%", "Point 3 = 0%" and "Point 

5 = +100%":

Input

Output

Point ?

0%

0%

–100%

C1

Normal

Thr

Curve off

Note:

As the throttle trim lever has no effect if the throttle 

limiter is open, its position here is unimportant.

Now – without starting the glow motor – adjust the 

throttle servo, preferably mechanically and optionally 

using the servo 6 travel adjustment option in the 

"Servo adjustments" menu, so that the carburetor is 

completely open. 

Now, close the throttle limiter completely by turning the 

CTRL 6 proportional rotary control in an anti-clockwise 

direction as far as it will go. Use the trim lever on the 

throttle/collective pitch stick to move the trim position 

marker to the "Motor OFF" position – see the fi gure in 

the next column.

Note:

In contrast, when the throttle limiter is closed, 

the position of the throttle/collective pitch stick is 

meaningless. It can therefore remain at the maximum 

collective pitch position so that, when adjusting 

carburetor linkages, the throttle limiter alone can be 

used to switch between full throttle (throttle limiter open) 

and "Motor OFF" (throttle limiter closed).

Now, with the throttle limiter closed, adjust the 

carburetor linkages so that the carburetor is (just) 

completely closed. Take extreme care to ensure that the 

throttle servo cannot travel mechanically to either of the 

two extreme positions (full thr./Motor OFF).

To complete this basic confi guration, the idle trim 

adjustment range must now be matched against point 

"L" on the throttle curve. To do so, set point "L" for the 

mixer "C1  Thr" on the "Helicopter mixers" menu 

from about -65% to -70%:

Input

Output

Point L

0%

0%

C1

Normal

Thr

Curve off

–66%

To confi gure a smooth transition from the idle trim to the 

throttle curve exactly, the collective pitch stick should 

be moved to and fro slightly at its minimum position with 

the throttle limiter closed and the idle trim fully open. 

The throttle servo must not move as well! Any further 

adjustments to the throttle curve must of course be 

made later in fl ight.

The motor is always started with the throttle limiter fully 

closed, whereby idle is set exclusively by using the trim 

lever of the throttle/collective pitch stick. 

Throttle limit in conjunction with digital trim

In conjunction with the CTRL 6 throttle limit rotary 

control, the C1 trim sets a marker ( ) in the motor's 

confi gured idle position, from which the motor can be 

switched off via the trim. If, on the other hand, a further 
106 Detail program description - Control adjust

marker is located at the end-point (see the partial 

display screenshot shown below), then you can simply 

click once to restore the original idle confi guration (see 

also page 54).

This switch-off trim functions as an idle trim only in the 

left half of the throttle limit rotary control's path. That 

is: only within this range is the marker line set and also 

stored. 

GRAUBELE

#01

3:33h

stop

 flt

K78

0:00

0:00

RX0.0V

5.2V

Last idle position

2.4 M

motor OFF position

CTRL 6

Throttle limit control

Current trim position

Trim at 

For this reason, the marker is hidden and may even be 

erased while the throttle limit rotary control points to the 

right of its center position:

GRAUBELE

#01

3:33h

Stop

Flt

K78

0:00

0:00

RX0.0V

5.2V

M 2.4CTRL 6

Throttle limit control

Notes:

• Since this trim function only takes effect in the 

"Motor OFF" direction, the screen image shown 

above changes appropriately if you alter the control 

direction for the pitch minimum position of the C1 

stick from "back" (as shown in the above image) to 

"forward" in the "min. pitch" line on the menu "Base 

setup model". The effects as shown also swap to 

the other side if you swap pitch right (as shown in the 

above screen images) to pitch left in the "Stick mode" 

line on the "Base setup model" menu (see page 74).

• You can use the "Servo display" menu to observe 

the infl uence of the throttle limit slider. This menu 

can be accessed from almost any other menu by 

simultaneously pressing the  keys on the left 

touch pad. Bear in mind that servo output 6 controls 

the throttle servo on the mx-20 HoTT!

• A servo connected to output 12 can be used 

independently of this for other purposes by means of 

mixers, provided that you separate the servo from the 

transmitter control at function input 12 on the "MIXonly channel" menu; see page 193.

• The throttle restriction set by the throttle limiter 

is shown as a horizontal bar in the throttle curve 

diagram on the second display page of the "Channel 

1  Throttle" option on the "Helicopter mixers" 

menu (see page 168). The output signal for the 

throttle servo cannot be higher than the level set by 

the horizontal bar: 

Input

Output

Point 2

0%

0%

0%

C1

Normal

Thr

Curve off

Throttle limiter 

position

The above diagram shows precisely this scenario: in 

the above example, the throttle limit control is set to 

-60% and thus restricts the movement of the throttle 

servo to -60% of full travel.

 Time delay for the throttle limiter

To safely avoid the carburetor opening too rapidly, you 

should assign throttle limiter input 12 a time delay that 

takes effect only in the direction of full throttle. This 

applies especially if you are controlling the throttle limiter 

using a switch and not the default CTRL 6 proportional 

rotary control.

To set a delay time, proceed as follows: turn the throttle 

limit control as far to the right as it will go or move the 

relevant switch to the full-throttle position; then use the 

arrow keys on the left or right touch pad to select the 

"–time+" column: 

– time +

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Normal

Input 9

Input10

Input

Th.L.12

11

After briefl y tapping the center SET key on the right 

touch pad, you can then use the arrow keys on the left 

or right touch pad to select your desired time delay, e. g. 

5 seconds:
Detail program description - Control adjust 107

– time +

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Normal

Input 9

Input10

Input

Th.L.12

11

5.0

Briefl y tap the center SET key on the right touch pad or 

the ESC key on the left touch pad to complete the setup 

procedure. 

As already explained on page 94, selecting "Thr AR" in 

the "Thr." line on the menu ...

"Stick mode" (page 94)

Thr.

Roll

Nick

Tr time +

4

4

4

0.0s

0.0s

0.0s

Tail 4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

St

TA

... makes the digital trim of the throttle/collective pitch 

stick active only in the "Autorot" fl ight phase. As a result, 

in "normal" fl ight phases, the C1 trim lever can be used 

neither to control the motor's idling nor to stop the motor. 

To ensure you still retain suffi cient adjustment options, 

we recommend using "Expo throttle limit" here.

This sub-menu for this is found on the menu ...

"Helicopter type" (page 86)

Expo thro lim. 0%

SEL

Linear. swashpl. no

Rotor direct right

HELI TYPE

Pitch min. back

... and the exponential curve characteristic it confi gures 

can adjust the control characteristics of the throttle limit 

control so that the latter provides suffi ciently fi ne control 

of the idle setting and can also stop the motor.

In this case you should turn the throttle limiter fully to 

the left – unlike the previously described setting on the 

"Control adjust" menu – and adjust the "–" side of the 

"–travel+" column in the "Th.L.12" line so the throttle 

 Throttle limit in conjunction with "Thr AR" on the "Stick mode" menu

limiter fully closes the carburetor, i.e. the motor is safely 

switched off at this control position.

Following this, move the throttle limit control to its center 

point and change the % value of the "Expo thro lim." line 

in the "Helicopter type" menu (see page 86) until the 

carburetor is in a position suitable for starting the motor. 

Now start the motor, and adjust the value if necessary 

until the motor idles reliably in this throttle limit control 

position.

For the plus side of the "–travel+" column, increase the 

value to +125% as described before, so that the fullthrottle position of the throttle servo is also released 

reliably by the throttle limiter.

Finally, set an asymmetrical time delay of, say, 

4.0 seconds, so that the motor also picks up speed 

gradually even if you move the proportional rotary 

control too quickly to the right. Select the time preset 

to correlate to how far the carburetor opens up at the 

minimum collective pitch position. The value you set will 

need fi ne-tuning by practical testing. 
108 Detail program description - Control adjust

 Dual Rate / Expo

Confi gurable control characteristics for aileron, elevator and rudder

Using the arrow keys on the left or right touch pad, page 

to the menu option "Dual Rate / Expo" in the multifunction list: 

Servo adjustment

Stick mode.

Channel 1 curve

Switch display

Control adjust.

Dual Rate / Expo

Tap the center SET key on the right touch pad to open 

the menu shown below:

100%

100%

100%

Ail

Ele

Rud

DUAL

–––

–––

–––

SEL

The Dual Rate / Expo function permits switching or 

controlling of control travels and characteristics for 

aileron (Ail), elevator (Ele) and rudder (Rud) (control 

functions 2 ... 4); it is switch-driven and fl ight-phase 

independent. 

The "Channel 1 curve" menu (see p. 116f.) can be 

used to set an individual curve characteristic for control 

function 1 (throttle/brake), featuring up to 6 separately 

programmable points.

As with transmitter control travel adjustment on the 

"Control adjust" menu, Dual Rate affects the relevant 

control function directly, whether it controls a single 

servo or multiple servos – via mixer and coupling 

functions of arbitrary complexity. 

The control travels for each switch position can be set to 

between 0% and 125% of the normal full travel. 

Expo, on the other hand, enables fi ner-grained control 

of the model for values larger than 0% around the 

center position of the primary control function (aileron, 

elevator and rudder), without forfeiting full movement 

at the end-points of joystick travel. For values less than 

0%, the reverse is true: control increases around the 

neutral position and diminishes towards the end-points. 

The degree of "progression" can therefore be set within 

a total range of -100% to +100%, where 0% equates to 

the normal, linear control characteristics.

Rotary-output servos, now generally commonplace, 

offer another application. This is because the actual 

control surface movement is not linear: as the rotational 

angle of the output disc or lever increases, the control 

surface rate of travel over the control linkage continually 

decreases – depending on the position of the linkage 

point on the output disc. You can counteract this effect 

with Expo values greater than 0%, so that angular travel 

increases over proportionately as stick travel increases.

The Expo setting also affects the relevant control 

function directly, whether this controls a single servo or 

multiple servos – via any number of mixer and coupling 

functions.

For both Dual Rate and Expo functions, switch 

assignment can be set up in any way desired, which 

therefore permits the triggering of multiple functions 

using one and the same switch. This, in turn, offers the 

opportunity to link the triggering of Dual Rate and Expo 

functions to a single switch: this offers many advantages 

– particularly for very high-speed models.

The graphic screen displays the curve characteristics 

directly. Once you select a menu line, the dotted vertical 

line follows the movement of the respective joystick, so 

you can clearly see the dependency of the curve value 

on the transmitter control.

Flight phase-dependent Dual Rate and Expo 

settings

If you have set up fl ight phases in the "Phase settings" 

and "Phase assignment" menus and assigned each of 

these a name – e. g. "normal" – the name in question 

is displayed at the bottom left. In this scenario, you can 

operate the corresponding switch to switch between 

fl ight phases.

Basic procedure

1. Switch to the desired fl ight phase and then use 

the arrow keys  on the left or right touch pad 

to select your chosen menu line, i.e. "Ail", "Ele" or 

"Rud".

2. Using the arrow keys  on the left or right touch 

pad, select the right column or the as-yet invisible 

column for Expo values (see page 27).

3. Tap the center SET key on the right touch pad. The 

corresponding input fi eld is shown highlighted.

4. the arrow keys on the right touch pad to set your Use 

chosen value.

5. Tap the center SET key on the right touch pad to 

complete data entry.

6. If you tap the  or  keys on the right touch 

pad at the same time (CLEAR), this will reset any 

settings made back to their respective default values.

Dual Rate function

If you want to be able to switch between two variants, 

assign a switch in the column marked with the switch 

icon at the lower edge of the display, as described in 

the section "Assigning transmitter controls, switches and 
Detail program description - Control adjust 109

100%

100%

DUAL

3

–––

–––

SEL

normal

Ail 111%

Ele

Rud

100%

100%

DUAL

3

–––

–––

SEL

normal

Ail 88%

Ele

Rud

If you tap the  or  keys on the right touch 

pad at the same time (CLEAR), this will reset a value 

changed in the highlighted fi eld back to 100%.

Caution:

For safety reasons, you should not set Dual Rate values 

lower than 20%.

Some examples of Dual Rate values: Servo travel Servo travel

Servo travel

Stick deflection Stick deflection Stick deflection

Dual Rate = 100% Dual Rate = 50% Dual Rate = 20%

Exponential function

If you want to be able to switch between two variants, 

use the  key on the left or right touch pad to move 

to the right beyond the Dual Rate value column, until 

control switches" (page 52):

100%

100%

100%

Ail

HR

SR

DUAL

–––

–––

–––

SEL

normal

Move desired switch

to ON position

(ext. switch: SET )

The switch so assigned appears on the display, together 

with a switch icon that indicates the switch's switching 

direction.

With "G" switches from the "expanded switches" menu, 

the joystick or another transmitter control acts as the 

switch itself. However, this kind of control switch must 

be defi ned appropriately beforehand on the "Control 

switches" menu (see page 123). 

Whichever switch has been assigned ... 

the respective switch appears on the display together 

with a switch icon that indicates the switch's respective 

direction when moved.

100%

100%

100%

Ail

Ele

Rud

DUAL

3

–––

–––

SEL

normal

If you select the right-hand column at the lower edge 

of the display marked with SEL and activate the value 

fi eld by briefl y tapping the center SET key on the right 

touch pad, you can use the arrow keys on the left or 

right touch pad to alter the Dual Rate value shown in the 

highlighted fi eld separately for each of the two switch 

positions:

the word "DUAL" (shown roughly in the middle of the 

display) changes to "EXPO":

0%

0%

0%

EXPO

–––

–––

–––

SEL

Ail

Ele

Rud

If you want to be able to switch between two variants, 

assign a switch in the column marked with the switch 

icon at the lower edge of the display, as described in 

the section "Assigning transmitter controls, switches and 

control switches" (page 52):

0%

100%

100%

Ail

Ele

SR

DUAL

–––

–––

–––

SEL

normal

Move desired switch

to ON position

(ext. switch: SET )

The switch so assigned appears on the display, together 

with a switch icon that indicates the switch's respective 

switching direction.

With "G" switches from the "expanded switches" menu, 

the joystick or another transmitter control acts as the 

switch itself. However, the control switch in question 

must be defi ned appropriately beforehand on the 

"Control switches" menu (see page 123). 

Whichever switch has been assigned ...

 the respective switch appears on the display together 

with a switch icon that indicates the switch's respective 

direction when moved.
110 Detail program description - Control adjust

0%

0%

0%

Ail

Ele

Rud

EXPO

3

–––

–––

SEL

normal

If you select the right-hand column at the lower edge 

of the display marked with SEL and activate the value 

fi eld by briefl y tapping the center SET key on the right 

touch pad, you can use the arrow keys on the left or 

right touch pad to alter the Expo value shown in the 

highlighted fi eld separately for each of the two switch 

positions:

Now, for example, you have the opportunity to fl y with 

a linear curve characteristic with the switch in one 

direction, and to pre-set a value other than 0% in the 

other switching direction:

33%

0%

0%

Ail

Ele

Rud

EXPO

3

–––

–––

SEL

normal

If you tap the  or  keys on the right touch 

pad at the same time (CLEAR), this will reset a value 

changed in the highlighted fi eld back to 0%.

Some examples of Expo values: Servo travel Servo travel

Servo travel

Stick deflection Stick deflection Stick deflection

Expo = +100% Expo = +50% Expo = –100%

In each of these examples, the Dual Rate value equals 

100%.

Combining Dual Rate and Expo

If you have entered values for both the Dual Rate 

and the Expo function, the effect from on function 

is superimposed on the other, as shown in these 

examples: Servo travel

Servo travel

Servo travel

Stick deflection Stick deflection Stick deflection

Expo = +100%, DR = 125% Expo = +100%, DR = 50% Expo = –100%, DR = 50%

Asymmetric setting of Dual Rate and Expo

To make an asymmetric setting, i. e. a Dual Rate or Expo 

setting dependent on the direction of the respective 

joystick, fi rst access the "Control switches" menu and 

assign one of the C1 ... C4 control switches – "C3", 

for example – your chosen transmitter control, e. g. 

control 3 for the elevator function. Leave the switching 

point at the joystick's neutral position (0%), however. 

Now return to the "Dual Rate / Expo" menu and select 

the corresponding control function ("Elevator" in this 

example). 

Activate "Switch assignment" and tap the center 

SET key briefl y on the right touch pad to switch to 

the expanded switches. Here, use the arrow keys to 

continue switching to the control switch "G3" that you 

defi ned previously:

100%

100%

100%

Ail

HR

SR

DUAL

–––

–––

–––

SEL

normal

Control / fix sw

C1 C2 C3 C4 FX

FXi C1i C2i C3i C4i

Tap the center SET key on the right touch pad to confi rm 

the assignment of this switch:

100%

100%

100%

Ail

Ele

Rud

DUAL

–––

C3

–––

SEL

normal

Now use one of the arrow keys to move to the right 

column and then move the elevator joystick to the 

appropriate end-point in order to enter a separate Dual 

Rate value for each direction, e. g. for "Up elevator" ... 

100%

100%

Ail

Ele

Rud

DUAL

–––

C3

–––

SEL

normal

77%

... and "Down elevator":
Detail program description - Control adjust 111

100%

100%

Ail

Ele

Rud

DUAL

–––

C3

–––

SEL

normal

111%

Set the Expo values in the same way.
112 Detail program description - Control adjust

 Dual Rate / Expo

Confi gurable control characteristics for roll, pitch-axis, tail rotor

Using the arrow keys on the left or right touch pad, page 

to the menu option "Dual Rate / Expo" in the multifunction list: 

Servo adjustment

Stick mode.

Channel 1 curve

Switch display

Control adjust.

Dual Rate / Expo

Tap the center SET key on the right touch pad to open 

the menu shown below:

100%

100%

100%

Roll

Nick

Tail

DUAL

–––

–––

–––

SEL

The Dual Rate / Expo function permits switching or 

controlling of control travels and characteristics for the 

control functions roll, pitch-axis, tail rotor, i. e. control 

functions 2 ... 4; it is switch-driven and fl ight-phase 

independent. 

An individual curve characteristic for control function 

1 (motor/collective pitch), featuring up to 6 separately 

programmable points, can be set either on the "Channel 

1 curve" menu (page 119) or separately for throttle and 

collective pitch on the "Helicopter mixers" menu (see 

p. 165f.).

As with transmitter control travel adjustment on the 

"Control adjust" menu, Dual Rate affects the relevant 

control function directly, whether it controls a single 

servo or multiple servos – via mixer and coupling 

functions of arbitrary complexity. 

The control travels for each switch position can be set to 

between 0% and 125% of the normal full travel. 

Expo, on the other hand, enables fi ner-grained control 

of the model for values larger than 0% around the center 

position of the primary control function (roll, pitch-axis, 

tail rotor), without forfeiting full movement at the endpoints of joystick travel. For values less than 0%, the 

reverse is true: control increases around the neutral 

position and diminishes towards the end-points. The 

degree of "progression" can therefore be set within a 

total range of -100% to +100%, where 0% equates to 

the normal, linear control characteristics.

Rotary-output servos, now generally commonplace, 

offer another application. This is because the actual 

control surface movement is not linear: as the rotational 

angle of the output disc or lever increases, the control 

surface rate of travel over the control linkage continually 

decreases – depending on the position of the linkage 

point on the output disc. You can counteract this effect 

with Expo values greater than 0%, so that angular travel 

increases overproportionately as stick travel increases.

The Expo setting also affects the relevant control 

function directly, whether this controls a single servo or 

multiple servos – via any number of mixer and coupling 

functions.

For both Dual Rate and Expo functions, switch 

assignment can be set up in any way desired, which 

therefore permits the triggering of multiple functions 

using one and the same switch. This, in turn, offers the 

opportunity to link the triggering of Dual Rate and Expo 

functions to a single switch: this offers many advantages 

– particularly for very high-speed models.

The graphic screen displays the curve characteristics 

directly. Once you select a menu line, the dotted vertical 

line follows the movement of the respective joystick, so 

you can clearly see the dependency of the curve value 

on the transmitter control.

Flight phase-dependent Dual Rate and Expo 

settings

If you have set up fl ight phases in the "Phase settings" 

and "Phase assignment" menus and assigned each of 

these a name – e. g. "normal" – the name in question 

is displayed at the bottom left. In this scenario, you can 

operate the corresponding switch to switch between 

fl ight phases.

Basic procedure

1. Switch to the desired fl ight phase and then use the 

arrow keys  on the left or right touch pad to 

select your chosen menu line, i.e. "Roll", "Nick" or 

"Tail".

2. Using the arrow keys  on the left or right touch 

pad, select the right column or the as-yet invisible 

column for Expo values (see page 27 ).

3. Tap the center SET key on the right touch pad. The 

corresponding input fi eld is shown highlighted.

4. the arrow keys on the right touch pad to set your Use 

chosen value.

5. Tap the center SET key on the right touch pad to 

complete data entry.

6. If you tap the  or  keys on the right touch 

pad at the same time (CLEAR), this will reset any 

settings made back to their respective default values.

Dual Rate function

If you want to be able to switch between two variants, 

assign a switch in the column marked with the switch 
Detail program description - Control adjust 113

use the  key on the left or right touch pad to move 

to the right beyond the Dual Rate value column, until 

the word "DUAL" (shown roughly in the middle of the 

display) changes to "EXPO":

0%

0%

0%

EXPO

–––

–––

–––

SEL

Roll

Nick

Tail

If you want to be able to switch between two variants, 

assign a switch in the column marked with the switch 

icon at the lower edge of the display, as described 

in the section "Assigning transmitter controls, switches 

and control switches" (page 52):

0%

100%

100%

Roll

Nick

SR

DUAL

–––

–––

–––

SEL

normal

Move desired switch

to ON position

(ext. switch: SET )

The switch so assigned appears on the display, together 

with a switch icon that indicates the switch's respective 

switching direction.

With "G" switches from the "expanded switches" menu, 

the joystick or another transmitter control acts as the 

switch itself. However, the control switch in question 

must be defi ned appropriately beforehand on the 

"Control switches " menu (see page 123). 

Whichever switch has been assigned ... the respective 

switch appears on the display together with a switch icon 

that indicates the switch's respective direction when moved.

icon at the lower edge of the display, as described 

in the section "Assigning transmitter controls, switches 

and control switches" (page 52 ):

100%

100%

100%

Roll

Nick

SR

DUAL

–––

–––

–––

SEL

normal

Move desired switch

to ON position

(ext. switch: SET )

The switch so assigned appears on the display, together 

with a switch icon that indicates the switch's switching 

direction.

With "G" switches from the "expanded switches" menu, 

the joystick or another transmitter control acts as the 

switch itself. However, this kind of control switch must 

be defi ned appropriately beforehand on the "Control 

switches" menu (see page 123). 

Whichever switch has been assigned ... 

the respective switch appears on the display together 

with a switch icon that indicates the switch's respective 

direction when moved.

100%

100%

100%

Roll

Nick

Tail

DUAL

3

–––

–––

SEL

normal

If you select the right-hand column at the lower edge 

of the display marked with SEL and activate the value 

fi eld by briefl y tapping the center SET key on the right 

touch pad, you can use the arrow keys on the left or 

right touch pad to alter the Dual Rate value shown in the 

highlighted fi eld separately for each of the two switch 

positions:

100%

100%

DUAL

3

–––

–––

SEL

normal

Roll 111%

Nick

Tail

100%

100%

DUAL

3

–––

–––

SEL

normal

Roll 88%

Nick

Tail

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset a value 

changed in the highlighted fi eld back to 100%.

Caution:

For safety reasons, you should not set Dual Rate values 

lower than 20%.

Some examples of Dual Rate values: Servo travel Servo travel

Servo travel

Stick deflection Stick deflection Stick deflection

Dual Rate = 100% Dual Rate = 50% Dual Rate = 20%

Exponential function

If you want to be able to switch between two variants, 
114 Detail program description - Control adjust

0%

0%

0%

EXPO

3

–––

–––

SEL

normal

Roll

Nick

Tail

If you select the right-handcolumn at the lower edge 

of the display marked with SEL and activate the value 

fi eld by briefl y tapping the center SET key on the right 

touch pad, you can use the arrow keys on the left or 

right touch pad to alter the Expo value shown in the 

highlighted fi eld separately for each of the two switch 

positions:

Now, for example, you have the opportunity to fl y with 

a linear curve characteristic with the switch in one 

direction, and to pre-set a value other than 0% in the 

other switching direction:

33%

0%

0%

EXPO

3

–––

–––

SEL

normal

Roll

Nick

Tail

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset a value 

changed in the highlighted fi eld back to 0%.

Some examples of Expo values: Servo travel Servo travel

Servo travel

Stick deflection Stick deflection Stick deflection

Expo = +100% Expo = +50% Expo = –100%

In each of these examples, the Dual Rate value equals 

100%.

Combining Dual Rate and Expo

If you have entered values for both the Dual Rate 

and the Expo function, the effect from on function 

is superimposed on the other, as shown in these 

examples: Servo travel

Servo travel

Servo travel

Stick deflection Stick deflection Stick deflection

Expo = +100%, DR = 125% Expo = +100%, DR = 50% Expo = –100%, DR = 50%

Asymmetric setting of Dual Rate and Expo

To make an asymmetric setting, i. e. a Dual Rate or Expo 

setting dependent on the direction of the respective 

joystick, fi rst access the "Control switches" menu and 

assign one of the C1 ... C4 control switches – "C3", for 

example – your chosen transmitter control, e. g. control 

3 for the pitch-axis function. Leave the switching point 

at the joystick's neutral position (0%), however. Now 

return to the "Dual Rate / Expo" menu and select the 

corresponding control function ("Nick" in this example). 

Activate "Switch assignment" and tap the center 

SET key briefl y on the right touch pad to switch to 

the expanded switches. Here, use the arrow keys to 

continue switching to the control switch "G3" that you 

defi ned previously:

100%

100%

100%

Roll

HR

SR

DUAL

–––

–––

–––

SEL

normal

Control / fix sw

C1 C2 C3 C4 FX

FXi C1i C2i C3i C4i

Tap the center SET key on the right touch pad to confi rm 

the assignment of this switch:

100%

100%

100%

DUAL

–––

C3

–––

SEL

normal

Roll

Nick

Tail

Now use one of the arrow keys to move to the right 

column and then move the pitch-axis joystick to the 

appropriate end-point in order to enter a separate Dual 

Rate value for each direction, e. g. for "Pitch-axis up" ... 

100%

100%

DUAL

–––

C3

–––

SEL

normal

Roll

Nick

Tail

77%

and "Pitch-axis down":
Detail program description - Control adjust 115

100%

100%

DUAL

–––

C3

–––

SEL

normal

Roll

Nick

Tail

111%

Set the Expo values in the same way.
116 Detail program description - Control adjust

 Channel 1 curve

Control characteristics for throttle/spoiler joystick

Using the arrow keys on the left or right touch pad, page 

to the menu option "Channel 1 curve" in the multifunction list: 

Servo adjustment

Stick mode

Switch display

Control adjust

Dual Rate / Expo

Channel 1 curve

Open this menu item by pressing the center SET button 

in the right touch pad.

Input

Output

Point ?

0%

0%

0%

C1

normal

Curve

Curve off

Since the carburetor response or the effect of the 

airbrakes or spoilers is often non-linear, you can make 

compensatory adjustments to these in this menu. 

The menu therefore enables you to change the 

control characteristics of the throttle / airbrake joystick, 

regardless of whether this control function affects the 

servo connected to control channel 1 directly or affects 

multiple servos via various mixers.

If you have used the "Phase settings" and "Phase 

assignment" menus (see pages 128 and 134) to 

specify fl ight phases, this option can be adjusted per 

fl ight phase. The fl ight phase name – e. g. "normal" – is 

always shown at the bottom left of the screen.

The control curve can be defi ned by up to 6 points 

(termed "reference points" below) placed anywhere 

along the path of joystick travel. While the on-screen 

graph considerably simplifi es the process of setting and 

adjusting the reference points, we recommend that you 

set fewer reference points to begin with.

In the basic software set-up, 2 reference points – 

namely the end-points at the bottom end of joystick 

travel ("L", low = -100% travel) and the top end of 

joystick travel ("H", high = +100% travel) – defi ne a 

linear characteristic curve.

First, switch to your chosen fl ight phase, if necessary.

 Setting reference points

By moving the transmitter control (throttle/airbrake 

joystick), you can reposition the vertical line in the graph 

between the two end-points "L" and "H". The current 

joystick position is also displayed in numerical form on 

the "Input" line (-100% to +100%). The point at which 

this line crosses the curve is termed the "Output", and 

can be varied at the reference points within the range 

-125% to +125%. The control signal altered in this 

way will then affect all subsequent mixer and coupling 

functions. 

In the example above, the joystick is at 0% of control 

travel and also generates an output signal of 0%, since 

the characteristic curve is linear.

Up to 4 additional reference points can be set between 

the two end-points "L" and "H", although the distance 

between neighboring reference points must not be less 

than approx. 25%.

If necessary, use the left or right arrow key  to drag 

the marker frame downwards, until it is at the "Point" 

line:

?

0%

0%

0%

Normal

off

Input

Output

Point

C1 Curve

Curve

Move the joystick. If a question mark can be seen in 

the frame, then you can set the next reference point 

by tapping the center SET key on the right touch pad. 

Simultaneously, the "?" is replaced by a number and the 

value fi eld to the right of the reference point number is 

highlighted:

1

+50%

+50%

+50%

Normal

off

Input

Output

Point

C1 Curve

Curve

The order in which you generate the (maximum) 4 

reference points between the end-points "L" and "H" is 

irrelevant, since the reference points are continuously 

renumbered automatically from left to right as they are 

entered.

 Deleting reference points

To delete one of the reference points (1 to max. 4), use 

the joystick to move the vertical line into the vicinity of 

the reference point in question. As soon as the reference 

point number and its associated value is shown on 

the "Point" line (see screen image above), you can 

activate the value fi eld on the "Point" line to highlight 

it by simultaneously tapping the  or  keys on 
Detail program description - Control adjust 117

the right touch pad (CLEAR) and then delete the value. 

Complete the operation by briefl y tapping the center key 

ESC on the left touch pad.

 Changing reference point values

Move the joystick into the range of the reference point 

that is to be changed: "L" (low), 1 ... 4 or "H" (high). 

The number and current curve value of this point are 

displayed. Activate the value fi eld by briefl y tapping 

the center SET key on the right touch pad. The point 

value fi eld is now highlighted and can be set within the 

range -125% to +125%, and without infl uencing the 

neighboring reference points.

Example:

2

+50%

–75%

–75%

Normal

off

Input

Output

Point

C1 Curve

Curve

In this sample screen image, reference point "2" has 

been set to -75%.

Note:

If the joystick does not coincide with the exact reference 

point, please note that the percentage value on the 

"Output" line always relates to the current joystick 

position.

 Trim point function

Alternatively, assuming the value fi eld is active, i. e. 

highlighted, you can use the up or down arrow keys 

 on the left touch pad to jump to reference points 

already set. In this case, a triangle is shown on the 

graph to indicate each point jumped to. The arrow keys 

on the right touch pad can then be used to change the 

reference point jumped to as described above, entirely 

independently of the control position:

2

+50%

–75%

–75%

Trim point

Normal

Input

Output

Point

C1 Curve

Exit from trim point function setting by tapping the center 

key ESC on the left touch pad.

 Trim offset function

Assuming the value fi eld is active, i. e. highlighted, you 

can not only use the up or down arrow keys  on the 

left touch pad to jump to reference points already set 

and change their values, but you can also use the 

keys on the left touch pad to vertically reposition an 

existing curve within the range ±25%:

1

0%

+50%

+50%

Trim offset

Normal

Input

Output

Point

C1 Curve

1

0%

0%

0%

Trim offset

Normal

Input

Output

Point

C1 Curve

You can also exit from this function by tapping the center 

key ESC on the left touch pad.

 Trim x-axis function

This function is activated by tapping the left () or right 

() arrow key on the right touch pad with an active 

(i. e. highlighted) value fi eld. You can then use the arrow 

keys on the right touch pad to reposition the active point 

horizontally or vertically as you wish.

?

0%

–33%

0%

Trim X-axis

Normal

Input

Output

Point

C1 Curve

Notes:

• If you reposition the point horizontally further away 

from the current control position than approx. ±25%, 

a "?" sign re-appears in the line. This question mark 

does not refer to the repositioned point, however: 

instead, it signifi es that a further point can be set at 

the current control position.

• Please note that the percentage value on the 

"Output" line always relates to the current joystick 

position and not to the position of the point.
118 Detail program description - Control adjust

 Smoothing the Channel 1 curve

In the example below, sample reference points have 

been set: 

Reference point 1 to 0%

Reference point 2 to +25%

Reference point 3 to -75%

as described in the last section. 

1

–50%

0%

0%

Normal

off

Input

Output

Point

C1 Curve

Curve

This "jagged" curve profi le can be smoothed 

automatically simply by pressing a button. 

First – assuming a situation is confi gured as presented 

above – tap the center ESC button on the left touch pad 

to deactivate the value fi eld. Then use the arrow keys on 

the left or right touch pad to move the marker frame in 

an upwards direction to the "Curve" line. Now briefl y tap 

the center SET key on the right touch pad to activate the 

value fi eld on the "Curve" line:

1

–50%

0%

0%

off

Normal

Input

Output

Point

C1 Curve

Curve

Use the arrow keys on the right touch pad to set the 

curve value from "off" to "on" and complete this setup 

procedure by briefl y tapping the center SET the center 

SET key on the right touch pad or the center ESC key 

on the left touch pad:

1

–50%

0%

0%

on

Normal

Input

Output

Point

C1 Curve

Curve

Note:

The curves shown here are for demonstration purposes 

only and are not at all representative of real throttle/

airbrake curves. For real-world application examples, 

see the programming examples from page 242 onwards.
Detail program description - Control adjust 119

 Channel 1 curve

Control characteristics for throttle/collective pitch stick

Using the arrow keys on the left or right touch pad, page 

to the menu option "Channel 1 curve" in the multifunction list: 

Servo adjustment

Stick mode

Switch display

Control adjust

Dual Rate / Expo

Channel 1 curve

Tap the center SET key on the right touch pad to open 

the menu shown below:

Input

Output

Point ?

0%

0%

0%

C1

normal

Curve

Curve off

Since the carburetor response or the effect of collective 

pitch is often non-linear, you can make compensatory 

adjustments to these in this menu. 

The menu therefore enables you to change the control 

characteristics of the motor/collective pitch stick, 

regardless of whether this control function affects the 

servo connected to control channel 1 directly or affects 

multiple servos via various mixers.

If you have used the "Phase settings" and "Phase 

assignment" menus (see pages 128 and 134 ) to 

specify fl ight phases, this option can be adjusted per 

fl ight phase. The fl ight phase name – e. g. "normal" – is 

always shown at the bottom left of the screen.

The control curve can be defi ned by up to 6 points 

(termed "reference points" below) placed anywhere 

along the path of joystick travel. While the on-screen 

graph considerably simplifi es the process of setting and 

adjusting the reference points, we recommend that you 

set fewer reference points to begin with.

Please note that the curve characteristic you set 

here acts as the input signal for specifi c mixers in the 

"Helicopter mixers" menu (see page 164):

 "Helicopter mixers" Collective pitch

stick

Collective pitch

C1  Thr

C1  Tail rotor

C1

curve

In the basic software set-up, 2 reference points – 

namely the end-points at the bottom end of joystick 

travel ("L", low = -100% travel) and the top end of 

joystick travel ("H", high = +100% travel) – defi ne a 

linear characteristic curve.

First, switch to your chosen fl ight phase, if necessary.

 Setting reference points

By moving the transmitter control (motor/collective pitch 

stick), you can reposition the vertical line in the graph 

between the two end-points "L" and "H". The current 

joystick position is also displayed in numerical form on 

the "Input" line (-100% to +100%). The point at which 

this line crosses the curve is termed the "Output", and 

can be varied at the reference points within the range 

-125% to +125%. The control signal altered in this 

way will then affect all subsequent mixer and coupling 

functions. 

In the example above, the joystick is at 0% of control 

travel and also generates an output signal of 0%, since 

the characteristic curve is linear.

Up to 4 additional reference points can be set between 

the two end-points "L" and "H", although the distance 

between neighboring reference points must not be less 

than approx. 25%.

If necessary, use the left or right arrow key  to drag the 

marker frame downwards, until it is at the "Point" line:

?

0%

0%

0%

Normal

off

Input

Output

Point

C1 Curve

Curve

Move the joystick. If a question mark can be seen in 

the frame, then you can set the next reference point 

by tapping the center SET key on the right touch pad. 

Simultaneously, the "?" is replaced by a number and the 

value fi eld to the right of the reference point number is 

highlighted:

1

+50%

+50%

+50%

Normal

off

Input

Output

Point

C1 Curve

Curve

The order in which you generate the (maximum) 4 

reference points between the end-points "L" and "H" is 

irrelevant, since the reference points are continuously 

renumbered automatically from left to right as they are 

entered.
120 Detail program description - Control adjust

Deleting reference points

To delete one of the reference points (1 to max. 4), use 

the joystick to move the vertical line into the vicinity 

of the reference point in question. As soon as the 

reference point number and its associated value is 

shown on the "Point" line (see screen image above), 

you can activate the value fi eld on the "Point" line to 

highlight it by simultaneously tapping the  or 

keys on the right touch pad (CLEAR) and then delete 

the value. Complete the operation by briefl y tapping the 

center key ESC on the left touch pad.

 Changing reference point values

Move the joystick into the range of the reference point 

that is to be changed: "L" (low), 1 ... 4 or "H" (high). 

The number and current curve value of this point are 

displayed. Activate the value fi eld by briefl y tapping 

the center SET key on the right touch pad. The point 

value fi eld is now highlighted and can be set within the 

range -125% to +125%, and without infl uencing the 

neighboring reference points.

Example:

2

+50%

–75%

–75%

Normal

off

Input

Output

Point

C1 Curve

Curve

In this sample screen image, reference point "2" has 

been set to -75%.

Note:

If the joystick does not coincide with the exact reference 

point, please note that the percentage value on the 

"Output" line always relates to the current joystick 

position.

 Trim point function

Alternatively, assuming the value fi eld is active, i. e. 

highlighted, you can use the up or down arrow keys 

 on the left touch pad to jump to reference points 

already set. In this case, a triangle is shown on the 

graph to indicate each point jumped to. The arrow keys 

on the right touch pad can then be used to change the 

reference point jumped to as described above, entirely 

independently of the control position:

2

+50%

–75%

–75%

Trim point

Normal

Input

Output

Point

C1 Curve

Exit from trim point function setting by tapping the center 

ESC key on the left touch pad.

 Trim offset function

Assuming the value fi eld is active, i. e. highlighted, you 

can not only use the up or down arrow keys  on the 

left touch pad to jump to reference points already set 

and change their values, but you can also use the 

keys on the left touch pad to vertically reposition an 

existing curve within the range ±25%:

1

0%

+50%

+50%

Trim offset

Normal

Input

Output

Point

C1 Curve

1

0%

0%

0%

Trim offset

Normal

Input

Output

Point

C1 Curve

You can also exit from this function by tapping the center 

ESC key on the left touch pad.

 Trim x-axis function

This function is activated by tapping the left () or right 

() arrow key n the right touch pad with an active (i. e. 

highlighted) value fi eld. You can then use the arrow 

keys on the right touch pad to reposition the active point 

horizontally or vertically as you wish.

?

0%

–33%

0%

Trim X-axis

Normal

Input

Output

Point

C1 Curve

Notes:

• If you reposition the point horizontally further away 

from the current control position than approx. ±25%, 

a "?" sign re-appears in the line. This question mark 
Detail program description - Control adjust 121

does not refer to the repositioned point, however: 

instead, it signifi es that a further point can be set at 

the current control position.

• Please note that the percentage value on the 

"Output" line always relates to the current joystick 

position and not to the position of the point.

 Smoothing the Channel 1 curve

In the example below, sample reference points have 

been set: 

Reference point 1 to 0%

Reference point 2 to +25%

Reference point 3 to -75%

as described in the last section.

1

–50%

0%

0%

Normal

off

Input

Output

Point

C1 Curve

Curve

This "jagged" curve profi le can be smoothed 

automatically simply by pressing a button. 

First – assuming a situation is confi gured as presented 

above – tap the center ESC button on the left touch pad 

to deactivate the value fi eld. Then use the arrow keys on 

the left or right touch pad to move the marker frame in 

an upwards direction to the "Curve" line. Now briefl y tap 

the center SET key on the right touch pad to activate the 

value fi eld on the "Curve" line:

1

–50%

0%

0%

off

Normal

Input

Output

Point

C1 Curve

Curve

Use the arrow keys on the right touch pad to set the 

curve value from "off" to "on" and complete this setup 

procedure by briefl y tapping the center SET key on the 

right touch pad or the center ESC key on the left touch 

pad:

1

–50%

0%

0%

on

Normal

Input

Output

Point

C1 Curve

Curve

Note:

The curves shown here are for demonstration purposes 

only and are not at all representative of real throttle/

airbrake curves. For real-world application examples, 

see the programming examples on pages 242 and 285.
122 Detail program description - Control adjust

 Switch display

Displaying switch positions

Using the arrow keys on the left or right touch pad, 

page to the menu option "Switch display" in the multifunction list: 

Switch display

Control switch

Channel 1 curve

Phase settings

Phase assignment

Phase trim

Tap the center SET key on the right touch pad to open 

the menu shown below:

Switch

Control Switch

1 2 3 4 5 6 7 8 9

C1 C2 C3 C4

This feature is used to check the functions and give an 

overview of SW switches 1 ... 9 and the programmable 

control switches.

If a switch is pressed, the switch number is revealed by 

one of the display items changing from an OFF to an ON 

symbol (or vice versa). To improve the legibility of this 

screen, a closed switch fi eld is also shown highlighted 

(i. e. it is shown on a dark background).

For control switches C1 ... C4, activation of the 

corresponding transmitter control – which must have 

been previously assigned on the "Control switch" menu 

– will reveal the control switch number and direction.

Note:

The switch numbering 1 to 9 as shown here 

corresponds to the labeling of the switches on the 

transmitter housing. The numbering of the switches 

has no effect on the programming of the transmitter, 

however.
Detail program description - Control adjust 123

 Control switches

Programming the control switches

Using the arrow keys on the left or right touch pad, 

page to the menu option "Control switch" in the multifunction list: 

Switch display

Channel 1 curve

Phase settings

Phase assignment

Phase trim

Control switch

Tap the center SET key on the right touch pad to open 

the menu shown below:

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

Gb1

Gb1

0%

STO

–––

–––

–––

With many functions, it makes sense not to trigger 

their actuation by using one of the normal switches, 

but to trigger them automatically by the specifi c, freely 

programmable position of a transmitter control or joystick.

Typical applications:

• Activation or deactivation of an onboard glowplug 

heating system depending on carburetor setting or 

motor speed (in this case, the switch for glowplug 

heating is controlled on the transmitter by a mixer)

• Switching a stopwatch on or off to measure the 

simple running time of electric motors

• Automated switch-off of a combi "aileron  rudder" 

mixer when extending the airbrakes, e. g. so as to 

match the bank attitude of the model to the ground 

slope when landing on a ridge, without the direction 

of fl ight also being affected by the rudder (if the mixer 

were active).

• Lowering landing fl aps, adjusting elevator trim and/

or executing specifi c Dual Rate, Exponential and 

Differential switchings when coming in to land, as 

soon as the throttle joystick is moved beyond the 

switching point. If required, a control switch can be 

overridden using a separately assigned switch in the 

5th column.

The mx-20 HoTT program is equipped with a total of 

4 of these control switches ("C1" to "G4").

Accordingly, anywhere where switches can be assigned 

you have the option not only of using the 9 possible 

transmitter switches, but also of choosing and assigning 

one of the "C1" ... "C4" control switches from the list 

of expanded switches – as described in the section 

"Assigning transmitter controls, switches and control 

switches" on page 52.

Furthermore, combining a control switch with an 

additional switch (as described later) also permits more 

complex switching permutations.

Basic procedure:

1. If no transmitter control is assigned, the 

corresponding input fi eld in the column above the left 

switch icon will be displayed empty.

2. Using the arrow keys on the left or right touch pad, 

select the line for the control switch you want (1 to 4).

3. Briefl y tap the center SET key on the right touch pad.

4. Move your selected transmitter control.

The associated transmitter control number appears 

in the input fi eld of the column above the left switch 

icon.

5. Using the arrow keys on the left or right touch pad, 

move to the right and the column above STO.

6. Move the transmitter control to the desired switching 

point and then briefl y tap the center SET key on the 

right touch pad to save the switching point.

7. Complete the remaining settings such as switching 

direction, etc.

8. Exit from the menu by using the center ESC key on 

the left touch pad. 

Assigning a transmitter control to a control switch

Using the arrow keys on the left or right touch pad, 

select your chosen line (1 to 4). After completing the 

activation of transmitter control assignment by tapping 

the center SET key on the right touch pad, the following 

message is shown:

SEL

+75%

0%

0%

G1

G2

C3

C4 –––

CONTROL SWITCH

Gb1

Gb1

–75%

STO

–––

––– Move desired –––

control adj.

As an example, the CTRL 6 proportional rotary control 

on the upper left is now to be assigned to the "C3" 

control switch. Accordingly, turn the dial of this control in 

any direction you want. As soon as this is detected, the 

control name appears on the display:
124 Detail program description - Control adjust

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

0%

STO

–––

–––

Ct6 –––

Resetting a control switch back to "free"

To reset a control switch back to "free", make sure the 

display is as below ...

SEL

+75%

0%

0%

G1

G2

C3

C4 –––

CONTROL SWITCH

Gb1

Gb1

–75%

STO

–––

––– Move desired –––

control adj.

... and then press the  or  keys on the right 

touch pad (CLEAR) briefl y to erase the transmitter 

control assignment.

Defi ning the switching point

Using the arrow key  on the left or right touch pad, 

move the marker frame into the STO (i.e. the STOre) 

column.

Move the selected transmitter control to the position at 

which the switching point – i. e. the switch between OFF/

ON – should trigger and briefl y tap the center SET key 

on the right touch pad. The current position is displayed, 

for example "+85%":

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

+85%

STO

–––

–––

Ct6 –––

The switching point can be altered at any time by 

tapping the center SET key on the right touch pad again.

Note:

Do not, however, set a switching point at a transmitter 

control's travel end-point, since this makes reliable 

switching impossible. Where a 3-stage switch (CTRL 9 

and 10) is used to operate a control switch you should 

therefore program the switching point beforehand using 

one of the proportional rotary controls (CTRL 6 to 8):

First, assign the corresponding proportional control in 

the 2nd column and set the switching point in such a 

way that will ensure the subsequent confi guration for 

the 3-stage switch will reliably exceed this value. If you 

do not, the switching function will be unreliable, since 

the control switch triggers only if a value unambiguously 

fails to meet or exceeds the value set! To complete the 

procedure, de-assign the transmitter control and then 

assign the 3-stage switch.

Setting the switching direction

The switching direction of the control switch is changed 

as required in the 4th column. Using the arrow key  on 

the left or right touch pad, move the marker frame into 

the SEL (i.e. the SELect) column. After briefl y tapping 

the center SET key on the right touch pad, you can then 

use the arrow keys on the left or right touch pad to set 

the switching direction from "normal" to "reversed" and 

vice versa:

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

+85%

STO

–––

–––

Ct6 –––

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

+85%

STO

–––

–––

Ct6 –––

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the switching direction 

to "=>".

The current switch position of the control switch is 

displayed in the leftmost column by the switch icon next 

to the number of the control switch.

Notes:

• In this example, control switch "C1" remains open 

while transmitter control 6 (the throttle limiter for 

a heli) is at less than +85% of full travel. It closes 

once the switching point is exceeded, i.e. by a value 

between +85% and the upper travel end-point.

• In the above example with the switching direction 

reversed, control switch "C1" remains closed while 

the transmitter control is at less than +85% of full 

travel. As soon as the switching point is exceeded – 

in this example, by a value between +85% and the 

upper travel end-point – "C3" opens.
Detail program description - Control adjust 125

• FIf a control switch – e. g. "C1" – has multiple 

assignments, you should bear in mind that the 

switching direction set here applies to all C3 

switches.

• The switch state can also be inverted by reversing 

the control on the "Control adjust" menu.

Combining a control switch with one of the SW 1 ... 

9 switches

The control switch can be overridden by a further switch, 

so that e. g. in certain fl ight situations the function to be 

triggered can be activated independently of the control 

position and thus the position of the control switch.

Switch to the value fi eld in the 5th column, the column 

above the right switch icon. In the simplest case, select 

one of the switches SW 1 ... 9 as described under 

"Assigning transmitter controls, switches and control 

switches" on page 52. The number of this switch, e. g. 

"2", appears on the display screen in the rightmost 

column, together with a switch icon that indicates the 

current state of the switch:

SEL

05%

05%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

Ct6 +85%

STO

2

–––

–––

While this switch is open, the "C1" control switch is 

active, i. e. it triggers at the switching point; if the switch 

is closed, the control switch now remains permanently 

closed as well, independently of the control position and 

switching direction:

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

–75%

STO

2

–––

–––

Ct6

Combining two control switches

For more complex applications, however, it can prove 

necessary to override this control switch with a second 

control switch.

Example:

Instead of being assigned the CTRL 6 control as 

before, the "C1" control switch is now assigned control 

function 3 (transmitter control 3). The switching point 

is at its center point, i.e. at 0%. The switch chosen in 

the rightmost column is "C2", from the list of expanded 

switches. We now assign one of the two center 

proportional rotary controls to this control switch "C2", 

on its own line – e. g. the right CTRL 8, whose switching 

point lies at +50%:

SEL

0%

0%

+50%

C1

C2

C3

C4 –––

CONTROL SWITCH

STO

–––

–––

Ct3 C2

Ct8

0%

Reading the switching directions given in the 4th column 

of the display, control switch "C3" remains closed while 

the joystick (K3) and/or "transmitter control 9" is/are 

beyond the switching point.

This diversity of switching options certainly offers you 

enough scope for specialized applications to suit any 

type of model.
126 Detail program description - Control adjust

 How do I program a fl ight phase?

The concept of fl ight phase programming

General information on fl ight phase programming

During a fl ight, you will often want to apply different 

settings – e.g. fl ap or trim settings for a fi xed-wing 

aircraft or collective pitch and throttle servo settings for 

a helicopter – at particular times in the fl ight (e. g. takeoff, approach, hover, auto-rotate, etc.). With mx-20

HoTT, you can access such presets automatically using 

switches or control switches.

Flight phases are also of great utility during fl ight testing. 

You can confi gure various set-ups and then switch 

between them during the fl ight: this enables you to 

identify the most appropriate program set-up for your 

model quickly and easily.

The basic programming procedure is a three-stage 

process

1. First, you have to set up the different fl ight phases, 

i. e. you assign names to phases 1 ... max. 7. Each 

name is then shown in all phase-specifi c menus and 

also on the basic display. To avoid abrupt transitions 

when switching between the various phases, you can 

also program a period of time during which a "soft" 

transition to the next phase takes place.

For fi xed-wing aircraft programs, these settings 

are made in the "Phase settings" menu. For heli 

programs, you either start with the "Base setup 

model" menu if you wish to set up autorotation or, 

if not, you also start programming with the "Phase 

settings" menu.

2. In the second stage, you use the "Phase 

assignment" menu to set up the required "phase 

switches".

3. Once these are set, you can then move to the fl ight 

phase-dependent menus (see the tables below) to 

start programming the settings for the individual fl ight 

phases.

 List of fl ight phase-relevant menus for fi xed-wing 

programs:

Menu Page

"Control adjust" 96

"Dual Rate / Expo" 108

"Channel 1 curve" 116

"Phase settings" 128

"Phase assignment" 134

"Phase trim" 136

"Non-delayed channels" 137

"Fl. phase timers" 142

"Wing mixers" 146

"MIX active/phase" 192

List of fl ight phase-relevant menus for helicopter 

programs:

Menu Page

"Control adjust" 100

"Dual Rate / Expo" 112

"Channel 1 curve" 119

"Phase settings" 132

"Phase assignment " 134

"Non-delayed channels" 137

"Fl. phase timers" 142

"Helicopter mixers" 164

"MIX active/phase" 192

All other menus are model-specifi c and thus cannot 

be programmed separately for each fl ight phase. 

Accordingly, changes you make in all other menus apply 

uniformly to all fl ight phases for that specifi c model. 

In some cases you may wish to use the "Suppress

menus" menu (see page 67) to remove the non-specifi c 

menus from the multi-function list when programming 

fl ight phases. A practical example of fl ight phase 

programming can be found on page 256).
Detail program description - Control adjust 127
128 Detail program description - Control adjust

 Phase settings

Setting up fl ight phases

 Setting up fl ight phases

When you set up fl ight phases for fi xed-wing aircraft 

models, you start with this menu. You assign individual 

phases a name and also assign a period of time for a 

(soft) transition into each phase. Note that – depending 

on your model and your settings – switch times much 

longer than the default 0.1 s have proven useful. You can 

also set up several phases with names and transition 

times even if you don't currently have a use for them, 

since the decision as to which of the "occupied" phases 

you activate is made only on the "Phase assignment" 

menu, (page 134) when setting "phase switches".

The "Status" column, second from the left, shows which 

one of the phases 1 ... 7 has already been assigned to 

a switch, plus the current status of that switch:

Symbol Meaning

– No switch assigned

+ Phase can be accessed via switch

 Indicates the phase currently active

Note:

The "Copy fl ight phase" option on the "Copy / Erase" 

menu is a useful aid when programming the various 

fl ight phases. First, you need to determine the 

parameters for a specifi c fl ight phase; these are then 

copied to the next fl ight phase, where they can then be 

modifi ed as appropriate.

Using the arrow keys on the left or right touch pad, 

page to the menu option "Phase settings" in the multifunction list: 

Phase settings

Phase assignment

Phase trim

Control switch

Timers (general)

Non-delayed chan

Tap the center SET key on the right touch pad to open 

this menu.

Within one model memory, the mc-20 HoTT lets you 

program up to 7 discrete groups of settings for various 

conditions met during the fl ight. The grouped settings 

are typically termed "fl ight phases" and are programmed 

in the corresponding menus.

Depending on the setting "Throttle min. forward/back" 

or "None" in the "Motor on C1" line of the "Model type" 

menu, your transmitter's display will look as follows after 

accessing the "Phase settings" menu ... 

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

... either the columns "Motor" and "Sw. time" (switch 

time) to the right of the column "ph. Tim." (fl . phase 

timers) or only the column "Sw. time" will be available for 

your settings. 

 "Name" column

Briefl y tap the center SET key on the right touch pad 

and use the arrow keys on the left or right touch pad to 

assign the phases your require – phase 1 to max. phase 

7 – appropriate names from the selection list. 

The order in which phases 1 to max. 7 are assigned is 

entirely irrelevant and you can leave gaps as you wish. 

Nonetheless, you should always start with "Phase 1", 

the "Normal phase", which is always active if ...

• no phase switch is set on the "Phase assignment" 

menu or if

• no phase has been assigned to specifi c combinations 

of switches.

The defi nition of the phase name "Normal" could 

therefore be a useful one to adopt for "Phase 1". 

The names themselves have absolutely no technical 

signifi cance for programming; their only purpose is to 

help you to identify which phase is active at any time 

and are thus displayed in all fl ight phase-dependent 

menus and also on the transmitter's basic display.

 "ph. Tim." column

In addition to the standard timers on the basic screen 

display, other timers are also available, whose settings 

are confi gured on the "Fl. phase timers" menu 

(page 142).

 Clk 1, Clk 2, Clk 3, Lap, Time1, Time2

The fl ight phase timers "Clk 1 ... 3" plus "Time1" and 

"Time2" run only in the fl ight phase to which they have 

been assigned in this menu. During other fl ight phases 

they are stopped (and hidden) and the assigned stop/

start switch then has no effect.

The lap counter, once started, continues to run through 
Detail program description - Control adjust 129

changes of phase, however, although it can be stopped 

during any fl ight phase via the center ESC key on the 

left touch pad.

While you can obviously record lap times using "Lap" 

and a switch (SW), the two timers "Time1" and "Time2" 

have the following meaning:

Time1 Only the times are measured at which the switch 

or control switch assigned in the "Lap timer/

timer" line of the "Fl. phase timers" menu (see 

page 142) is "closed". The frequency at which 

the switch is activated is shown on the basic 

display. This counter fi eld is highlighted as soon 

as the switch for the "Time1" timer is "opened", 

i. e. the timer is stopped:

GRAUBELE

#01

2:22h

Stop

Flt

«Speed »

K78

0:00

0:00

5.5V

5.2V 0:00.0

M

Lap 00

 If required, you can then use the arrow keys to 

access and read the times at which switches 

were made.

Application:

Measurement of e. g. motor switch-on times, if 

the same switch also actuates the motor.

Time2 "Time2" stores both the "Off" and the "On" times 

for the associated switch, i. e. each actuation of 

the switch restarts the time count again and the 

counter is incremented by "1".

 Each time count can be stopped by using the 

center ESC key on the right touch pad, without 

activating the switch itself. Activating the switch, 

in turn, increments the counter by 1 and restarts 

the "Time2" timer.

 In order to read out the time memory by using the 

arrow keys, the "Time2" timer must fi rst be stopped 

by using the ESC key on the right touch pad.

Application:

In addition to the motor runtimes, for example, 

the unpowered glide times between these could 

also be recorded. 

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the display of stopped 

timers on the basic display.

 "Motor" column

Note:

This column is only available if "Forward/back" is 

entered on the line "Motor on C1" on the "Model type" 

menu. 

Pha1

Pha2

Pha3

Name motor

Pha4

Pha5



+

+

Normal

Launch

Dist.

–

–

yes

yes

yes

yes

yes

"Yes" The motor connected to receiver output 1 will 

be controlled by the C1 joystick (throttle/brake 

stick).

 The brake system to be set up on the "Wing 

mixers" menu is deactivated:

BRAKE SETTINGS

normal

Normal

off

"No" The motor connected to receiver output 1 

is decoupled from the C1 joystick (throttle/

brake stick) and is held in its OFF position – as 

specifi ed by the setting "Throttle min. forward / 

back" – automatically.

 The brake system to be set up on the "Wing 

mixers" menu is activated and is actuated by 

the C1 joystick.

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red

0%

0%

0% 0%

0% 0%

WK WK2

Normal

Note:

The settings available depend on the number of control 

surface servos selected on the line "Ailerons/Camberchanging fl aps in the "Model type" menu.

 "Sw. time" column

When you switch between fl ight phases, it is advisable 

to use this column to program a switch time for a "soft" 

transition INTO (!) the respective phase. Accordingly, 

there is also the option of specifying different times for 

different switches – e. g. from a phase into Phase 3 and 

the same phase into Phase 1. 
130 Detail program description - Control adjust

Using the arrow key  on the left or right touch pad, 

move the marker frame over the "ph. Tim." column – and 

"Motor" column, if applicable – to the right.

Pha1

Pha2

Pha3

Name Sw.time

Pha4

Pha5



+

+

Normal

Launch

Dist.

–

–

0.1s

0.1s

0.1s

0.1s

0.1s

Briefl y tap the center SET key on the right touch pad to 

highlight the value fi eld. You can then select switch times 

between 0 and 9.9 s in this fi eld. 

Example:

Pha1

Pha2

Pha3

Name

Pha4

Pha5



+

+

–

–

3.0s

2.0s

4.0s

0.1s

0.1s

Sw.time

Normal

Launch

Dist.

The switch time is set to 4.0 s when switching from any 

phase to Phase 1 "Normal". 

When switching from e. g. Phase 1 to Phase 3, the 

switch time is set to 2.0 s and to 3.0 s when switching 

from Phase 1 or 3 to Phase 2 "Launch".

Such asymmetric transition times can be useful when 

(e. g.) switching between highly contrasting fl ight phases, 

such as e. g. between aerobatics and normal fl ight.

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the time to 0.1 in the 

active value fi eld.

Note:

The "switch time" set here applies uniformly to all 

settings that are specifi c to fl ight phases, and thus to 

all mixers activated in the "Wing mixers" menu (see 

page 146). Accordingly, the transition between fl ight 

phase-specifi c mixers does not occur abruptly. If you 

want individual servos to be switched without a delay, 

however, defi ne these accordingly in the "Non-delayed 

channels" menu (see page 137).
Detail program description - Control adjust 131
132 Detail program description - Control adjust

Using the arrow keys on the left or right touch pad, 

page to the menu option "Phase settings" in the multifunction list: 

Phase settings

Phase assignment

Control switch

Timers (general)

Non-delayed chan

Fl. phase timers

Tap the center SET key on the right touch pad to open 

the menu shown below:

Auto

Pha1

Pha2

Name ph.Tim.

Pha3 –

–

–

–

Pha4

 Autorot

Within one model memory, the mx-20 HoTT lets you 

program up to 6 discrete groups of settings for various 

conditions met during the fl ight. These are in addition to 

the auto-rotation fl ight phase that can be set up in the 

"Base setup model" menu. The grouped settings are 

typically termed "fl ight phases" and are programmed in 

the corresponding menus.

 Setting up fl ight phases

When you set up fl ight phases for helicopter models, 

you start with this menu. You assign individual phases 

a name and also assign a period of time for a (soft) 

transition into each phase. Note that – depending on 

your model and your settings – switch times much longer 

than the default 0.1 s have proven useful. You can also 

set up several phases with names and transition times 

 Phase settings

Setting up fl ight phases

even if you don't currently have a use for them, since 

the decision as to which of the "occupied" phases you 

activate is made only on the "Phase assignment" menu 

(page 134) when setting "phase switches".

The "Status" column, second from the left, shows which 

one of the phases 1 ... 6 has already been assigned to 

a switch, plus the current status of that switch:

Symbol Meaning

– No switch assigned

+ Phase can be accessed via switch

 Indicates the phase currently active

Note:

The "Copy fl ight phase" option on the "Copy / Erase" 

menu is a useful aid when programming the various 

fl ight phases. First, you need to determine the 

parameters for a specifi c fl ight phase; these are then 

copied to the next fl ight phase, where they can then be 

modifi ed as appropriate.

 "Name" column

The fi rst line, and thus the fl ight phase with top priority, 

is reserved for auto-rotation fl ight – see the "Base setup 

model" menu. Accordingly, the predefi ned name cannot 

be changed.

Use the arrow keys to move to the line "Pha1". Briefl y 

tap the center SET key on the right touch pad and use 

the arrow keys on the left or right touch pad to assign 

each of the phases your require – phase 1 to max. 

phase 6 – an appropriate name from the selection list. 

The order in which phases 1 to max. 6 are assigned is 

entirely irrelevant and you can leave gaps as you wish. 

Nonetheless, you should always start with "Phase 1", 

the "Normal phase", which is always active if ...

• no phase switch is set on the "Phase assignment" 

menu or if

• no phase has been assigned to specifi c combinations 

of switches.

The defi nition of the phase name "Normal" could 

therefore be a useful one to adopt for "Phase 1". 

The names themselves have absolutely no technical 

signifi cance for programming; their only purpose is to 

help you to identify which phase is active at any time 

and are thus displayed in all fl ight phase-dependent 

menus and also on the transmitter's basic display.

 "ph. Tim." column

In addition to the standard timers on the basic screen 

display, other timers are also available, whose settings 

are confi gured on the "Fl. phase timers" menu 

(page142).

 Clk 1, Clk 2, Clk 3, Lap, Time1, Time2

The fl ight phase timers "Clk 1 ... 3" plus "Time1" and 

"Time2" run only in the fl ight phase to which they have 

been assigned in this menu. During other fl ight phases 

they are stopped (and hidden) and the assigned stop/

start switch then has no effect.

The lap counter, once started, continues to run through 

changes of phase, however, although it can be stopped 

during any fl ight phase via the center ESC key on the 

left touch pad.

While you can obviously record lap times using "Lap" 

and a switch (SW), the two timers "Time1" and "Time2" 

have the following meaning:

Time1 Only the times are measured at which the switch 

or control switch assigned in the "Lap timer/

timer" line of the "Fl. phase timers" menu (see 
Detail program description - Control adjust 133

page 142) is "closed". The frequency at which 

the switch is activated is shown on the basic 

display. This counter fi eld is highlighted as soon 

as the switch for the "Time1" timer is "opened", 

i. e. the timer is stopped:

STARLET

#01

2:22h

Stop

Flt

«Speed »

K78

0:00

0:00

5.5V

5.2V 0:00.0

M

Lap 00

 If required, you can then use the arrow keys to 

access and read the times at which switches 

were made.

Application:

Measurement of (e. g.) fl ight phases with 

increased motor speed, if the same switch is 

used to actuate fl ight phase switching.

Time2 "Time2" stores both the "Off" and the "On" times 

for the associated switch, i. e. each actuation of 

the switch restarts the time count again and the 

counter is incremented by "1".

 Each time count can be stopped by using the 

center ESC key on the right touch pad, without 

activating the switch itself. Activating the switch, 

in turn, increments the counter by 1 and restarts 

the "Time2" timer.

 In order to read out the time memory by using 

the arrow keys, the "Time2" timer must fi rst be 

stopped by using the ESC key on the right touch 

pad.

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the display of stopped 

timers on the basic display.

 "Sw. time" column

When you switch between fl ight phases, it is advisable 

to use this column to program a switch time for a "soft" 

transition INTO (!) the respective phase. Accordingly, 

there is also the option of specifying different times for 

different switches – e. g. from a phase into Phase 3 and 

the same phase into Phase 1.

For safety reasons, however, the transition to the autorotation fl ight phase ALWAYS occurs without any time 

delay. The angled bracket ">" in the "Sw. time" column at 

the end of the "Auto" line indicates that a delay can be 

set when transitioning FROM (!) auto-rotation INTO (!) 

another phase.

Using the arrow key  on the left or right touch pad, 

move the marker frame over the "ph. Tim." column to the 

right.

Pha1

Pha2

Pha3

Name Sw.time

Pha4



+

+

Normal

Hover

–

–

0.1s

0.1s

0.1s

0.1s

0.1s

Speed

Auto Autorot

Briefl y tap the center SET key on the right touch pad to 

highlight the value fi eld. You can then select switch times 

between 0 and 9.9 s in this fi eld. 

Example:

Pha1

Pha2

Pha3

Name Sw.time

Pha4



+

+

Normal

Hover

–

–

3.0s

2.0s

5.5s

4.0s

0.1s

Speed

Auto Autorot

A delay of 5.5 s applies when switching FROM autorotation into any other phase. A delay of 0.0 s always 

applies when switching TO auto-rotation.

The switch time is 3.0 s when switching from any other 

phase to Phase 1 "Normal". 

When switching from e. g. Phase 1 to Phase 3, the 

switch time is set to 4.0 s.

Such asymmetric transition times can be useful when 

(e. g.) switching between highly contrasting fl ight phases, 

such as e. g. between aerobatics and normal fl ight.

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the time to 0.1 in the 

active value fi eld.

Note:

The "switch time" set here applies uniformly to all 

settings that are specifi c to fl ight phases, and thus to 

all mixers activated in the "Wing mixers" menu (see 

page 146). Accordingly, the transition between fl ight 

phase-specifi c mixers does not occur abruptly. If you 

want individual servos to be switched without a delay, 

however, defi ne these accordingly in the "Non-delayed 

channels" menu (see page 137).
134 Detail program description - Control adjust

 Phase assignment

Setting up fl ight phases

Using the arrow keys on the left or right touch pad, page 

to the menu option "Phase assignment" in the multifunction list: 

Phase settings

Phase trim

Control switch

Timers (general)

Non-delayed chan

Phase assignment

Fl. phase timers

Phase settings

Control switch

Timers (general)

Non-delayed chan

Phase assignment

Tap the center SET key on the right touch pad to open 

the menu shown below:

PHASE ASSIGNMENT

prior.

A B C D E F 

1 normal

combi

Note:

A phase name appears to the right of the phase number 

at the bottom right of the display only if you have 

assigned the name beforehand on the "Phase settings" 

menu.

On the "Phase settings" menu – described above 

separately for fi xed-wing and helicopter models – you 

will have set up names for your phases. On this menu – 

which is identical for both model types – you must now 

specify the switches or switch combinations that you 

want to use to trigger each phase. One exception for heli 

menu: one of the two auto-rotation switches must be set 

on the menu "Base setup model".

Please note the following priorities:

• If you have not yet assigned any fl ight phase 

switches to any phase names, you will always fi nd 

yourself in fl ight phase "1". Accordingly, by the time 

you start programming fl ight phases, you should 

therefore have already given this fl ight phase the 

phase name "Normal".

• Independently of the switch positions of phases 

assigned to switches using this menu, the autorotation phase – applicable only to the "Helicopter" 

model type and whose switch is assigned on the 

"Base setup model" menu – always (!) takes 

precedence. Accordingly, as soon as the autorotation switch in question is activated, the following 

warning appears:

A B C D E F 

1 normal

PHASE ASSIGNMENT

prior. combi

Autorot

• Phase switch "A" is given priority over all subsequent 

switch positions, from "B" to "F"

• Phase switch "B" is given priority over all subsequent 

switch positions, from "C" to "F"

• The two 3-stage switches, SW 4/5 and 6/7, should 

always be assigned from the center point position.

For this reason, use switch "A" and/or switch "B" only if 

you wish to change from any other fl ight phase – apart 

from the heli's auto-rotation phase – directly into the 

phase that is assigned to this switch.

 Programming fl ight phase switches

Once you have confi gured your desired switch position, 

"A" to "F", using the arrow keys on the left or right 

touch pad, a switch (whether a "normal" switch or an 

expanded switch) is then assigned as described in the 

section "Assigning transmitter controls, switches and 

control switches" (page 52).

• The order in which assignment is made is irrelevant: 

you must ensure only that you assign what are, for 

you, the "correct" switches. (In the heli program, for 

example, you should also take care to ensure you do 

not use this menu to re-assign any auto-rotation switch 

already assigned on the " Base setup model" menu.)

Example: 4 fl ight phases with phase priority 

A B C D E F 

1 Normal

2 6 7

PHASE ASSIGNMENT

prior. combi

 Assigning fl ight phases to switch positions

You have now assigned names to the fl ight phases (1 

... max. 7) on the "Phase settings" menu and also 

programmed switches on this menu, but ... at the bottom 

right of the display screen, you only see "<1 normal >" – 

regardless of the positions the switches are in!?
Detail program description - Control adjust 135

Use the arrow keys on the left or right touch pad to 

move the marker frame down and to the right and then 

briefl y tap the center SET key on the right touch pad:

A B C D E F 

2 6 7

1 Normal

PHASE ASSIGNMENT

prior. combi

Now close one (or more, as required) of the switches 

that you have assigned, and assign one of the fl ight 

phase names from the list you selected beforehand on 

the "Phase settings" menu to this switch position or 

combination. 

Here, for example, we assign the "Launch" phase to the 

closed ("I") priority switch "A" ...

A B C D E F 

2 6 7

2 Launch

PHASE ASSIGNMENT

prior. combi

... if, for example, we wish to switch to this phase 

regardless of the "C" ... "F" switch positions, because 

the same switch activates an electric motor, etc.

Use the same approach to set the other switches or 

combinations of switches.

Theoretically – for the situation where all three are 

closed – you could use the three single switches shown 

in the example to defi ne an additional fi fth fl ight phase 

on the "Phase settings" menu. However, since this 

example assumes just four fl ight phases, you can leave 

the default phase name as "1 Normal" for this switch 

position.

You can leave this menu in the familiar way by pressing 

the center ESC key on the left touch pad.

Tips:

• If you have named more phases than you currently 

have switches defi ned for then this is not really 

problematic. You can repeat and change your switch 

assignment as you wish at any point in time. And you 

can also name additional phases at any time and 

then assign switches to them.

• When assigning switches, check whether the 

switches are already otherwise assigned to ensure 

that you avoid duplicate assignments.

Important notice:

Before a phase switch is assigned, the model 

settings confi gured are now to be found in the fl ight 

phase "1 Normal", i. e. all fl ight phase-dependent 

menus are reset to the standard confi gurations for 

all other fl ight phases.

To avoid having to start from scratch in every fl ight 

phase, you can copy over these standard settings 

by using the command "Copy fl ight phase" on the 

"Copy / Erase" menu to replace them with fl ight 

data obtained from the "Normal" fl ight phase. You 

then need only to make further fl ight phase-specifi c 

changes to the settings.
136 Detail program description - Control adjust

 Phase trim

Flap settings specifi c to fl ight phases

Using the arrow keys on the left or right touch pad, page 

to the menu option "Phase trim" in the multi-function 

list: 

Phase settings

Phase assignment

Control switch

Timers (general)

Non-delayed chan

Phase trim

Tap the center SET key on the right touch pad to open 

the menu shown below:

Normal 0%

normal ELEV

Depending on the settings made on the "Aile/fl aps" 

line from the "Model type" menu (page 82) and on the 

"Phase settings" menu, this menu makes available a 

set of control functions – 1 for EL ...

Normal 0%

Normal ELEV

... and up to 4 for EL, RU, AI and AI2 – for the 

confi guration of trim settings that are specifi c to fl ight 

phases. The setting of the fl ight phase switches – to be 

defi ned beforehand on the "Phase assignment" menu 

– determines the line that is chosen. An asterisk marks 

the fl ight phase currently active. At the same time, the 

name of the respective fl ight phase is also shown at the 

bottom left of the screen. You can enter settings only for 

the currently active fl ight phase, e. g.:

Normal



0%

Launch ELEV

0%

AILE

Launch

Thermal

Dist.

0% 0%

0% 0%

0% 0%

"ELEV" column In this column, you can store a phasespecifi c elevator trim setting. 

Important notice:

Settings made in this column have an 

immediate effect on elevator trim and, 

accordingly, the trim setting display. In 

turn, the elevator trim lever affects the 

values of this column either "globally" 

or "phase-specifi cally", depending on 

the "global/phase" setting made on the 

"Elev" line of the "Stick mode" menu. 

"AILE", "FLAP", "FLAP2"

 The values in these columns (max. 3) 

are identical to those in the "Fl.pos" (fl ap 

position) line on the "Multi-fl ap menu" 

within the "Wing mixers" menu. For this 

reason, any changes made always affect 

the other menu directly – and vice versa.



0%

FLAP

0%

FLAP2

0% 0%

0% 0%

0% 0%

Normal

Launch

Launch

Thermal

Dist.

Note:

If present, you can access the "FLAP" and "FLAP2" 

columns by using the arrow keys  on the left or right 

touch pad to go beyond the right edge of the screen and 

back, as appropriate. 

After selecting the appropriate column, by using the 

arrow keys on the left or right touch pad and then 

briefl y tapping the center SET key on the right touch 

pad, you can then use the arrow keys to set the values 

independently of one another, within a range of ±150%. 

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the highlighted value fi eld back to 0%.
Detail program description - Control adjust 137

 Non-delayed channels

Channel-dependent delays to switching

Using the arrow keys on the left or right touch pad, page 

to the menu option "Phase trim" in the multi-function 

list: 

Phase settings

Phase trim

Control switch

Timers (general)

Phase assignment

Non-delayed chan

Phase settings

Control switch

Timers (general)

Fl. phase timers

Phase assignment

Non-delayed chan

Tap the center SET key on the right touch pad to open 

the menu shown below:

NONDELAYED CHANNELS

non-delay

normal

Normal

123 4 5 6

On the "Phase settings" menu, you will have set the 

necessary switch times for fl ight phase transitions.

In this menu, you can now deactivate the transition delay 

set previously, per fl ight phase and for individual control 

channels – e. g. for the motor channel for electric models 

or heading-lock systems for heli gyros, etc.

Switch over to the corresponding fl ight phase. This is 

shown at the bottom left of the display.

Use the arrow keys on the left or right touch pad to 

move the "" onto the corresponding channel and then 

briefl y tap the center SET key on the right touch pad.

The switch icon changes from "normal" to "non-delay" 

and vice versa. For example:

NONDELAYED CHANNELS

non-delay

normal

Normal

789 10 11 12

Note:

To access channels 7 ... 12, follow the description on 

page 27: use the arrow keys  on the left or right 

touch pad to go beyond the right edge of the screen and 

back, as appropriate. 
138 Detail program description - Control adjust

 Timers (general)

Timers on the basic display

The default transmitter display shows a total of three 

timers. These are: the transmitter operating time on the 

left of the display, plus a "Top" and a "Centr" timer on the 

right of the display:

GRAUBELE

#01

0:00h

Stop

Flt

K78

0:00

0:00

0.0V

5.9V

M

HoTT

A further, fl ight-phase specifi c timer can also be 

confi gured, depending on your settings in the two menus 

"Fl. phase timers" (page 142) and "Phase settings" 

(pages 128 and 132). This optional fl ight phase timer 

– such as the lap time timer – appears underneath the 

"Centr" (fl ight time) timer:

GRAUBELE

#01

2:22h

Stop

Flt

«Speed »

K78

0:00

0:00

5.5V

5.2V 0:00.0

M

Lap 00

To confi gure the "Top" and/or "Centr" timer, use the 

arrow keys on the left or right touch pad to access the 

menu option "Timers (general)" in the multi-function list: 

Non-delayed chan

Timers (general)

Fl. phase timers

Wing mixers

Free mixers

MIX active/phase

Non-delayed chan

Timers (general)

Fl. phase timers

Helicopter mixer

Free mixers

MIX active/phase

Tap the center SET key on the right touch pad to open 

the menu shown below:

Model time

Batt. time

Top :

Centr:

Stop

Flight

Timer

12:34h –––

1:23h

0:00

0:00

" Model time"

This timer shows the currently recorded total access 

time to the currently active model memory. If necessary, 

you can also infl uence the automated time recording 

using a switch assigned at the right of the display, and 

use this switch to activate and deactivate the "Model 

time" timer as required. This switch is assigned (and 

erased again as required) as described in the section 

"Assigning transmitter controls, switches and control 

switches" on page 52.

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the time to "0:00h".

" Batt. time"

This operating hours timer records the transmitter's 

total switch-on time since the last time the battery was 

charged, thus monitoring the transmitter battery. A 

switch cannot be assigned to this function.

This timer is automatically reset to "0:00h" when the 

transmitter detects that the voltage of the battery is 

signifi cantly higher than the last time it was switched on, 

e. g. as a result of a charge process or the installation of 

a replacement battery.

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will also reset the time here to 

"0:00h".

 "Top" and "Centr"

These two timers are located at the top right of the basic 

display (see the screen image immediately to the left) 

and can be assigned a different name; their function and 

mode of operation varies according to the name you 

give them. Independently of the name each is given, 

the "Top" and "Centr" timer can be programmed to run 

any length of time forwards or backwards – see further 

below.

Using the arrow keys on the left or right touch pad, 

select the line for the "Top" or "Centr" timer. Tap the 

center SET key on the right touch pad briefl y to activate 

the selection of a timer type:

Timer

12:34h –––

1:23h

0:00

0:00

Stop

SEL

Model time

Batt. time

Top :

Centr:Flight

Now use the arrow keys on the left or right touch pad to 

select your desired timer and complete your selection 

by once again tapping the center SET key on the right 

touch pad:
Detail program description - Control adjust 139

 "Stop (watch)" or "Motor (runtime)"

Both of these two timer variants can be started and 

stopped using any of the available switches.

The timer defi ned as "Stopwatch" or "Motor runtime" 

sums the "ON" times continually, so that once your 

aircraft has landed, you can read off the sum of all 

switch "ON" times since the timer was last reset.

 "Flight (time)"

This timer is designed for measuring the fl ight time: it 

can be started with an assigned switch and stopped 

(once the switch has been re-opened) on the basic 

display by tapping the center ESC key on the left touch 

pad. Once in a stopped state, it can be reset to its 

starting value by tapping the  or  keys on the 

right touch pad at the same time (CLEAR). 

If you wish to assign a control switch, you must fi rst 

defi ne the switch on the "Control switch" menu and 

specify the switching point along the travel of the 

transmitter control. As an example, the timer can then 

be started by "opening the throttle" or by opening the 

throttle limiter for heli models.

Note:

The combination of the fl ight time timer and stopwatch 

means that you can glance at the display at any time 

and see how long you have been fl ying since the timers 

were started, plus the total motor runtime within this 

particular period of fl ight time.

 "Frame(time)"

The timeframe timer is intended primarily for use by 

competition pilots, who are frequently given a timeframe 

within which they must complete certain tasks. The timer 

is started in precisely the same way as the fl ight time 

timer. To stop the timer, fi rst ensure the timer switch is 

at its OFF position. Then, press and hold the arrow keys 

, and then press the center ESC key.

Switch assignment

Using the arrow key  on the left or right touch pad, 

move the marker frame next to the triangle as shown in 

the screen image shown below to the rightmost column 

of the relevant line:

Alarm

12:34h –––

1:23h

0s

0s

–––

–––

SEL

Model time

Batt. time

Top :

Centr:

Stop

Flight

Here, you assign a switch as described in the section 

"Assigning transmitter controls, switches and control 

switches" (page 52).

Typical application:

The "stop watch" and "fl ight timer" are both to be started 

simultaneously using the C1 stick as soon as a userdefi ned switching point is exceeded.

For this purpose, you will defi ne e.g. "C1" on the

"Control switch" menu (page 123 ). To complete the 

procedure, you select this from the expanded switches 

(see the section "Assigning transmitter controls, 

switches and control switches" on page 52) and assign 

it to both these lines:

Alarm

12:34h –––

1:23h

0s

0s

C1

SEL

C1

Model time

Batt. time

Top :

Centr:

Stop

Flight

The stopwatch will now stop when the stick is below the 

switching point and resume running above the switching 

point. The same is not true for the fl ight time timer, 

however, which also starts the fi rst time the switching 

point is exceeded. It can be stopped (by tapping the 

center ESC key on the left touch pad) only once the 

stopwatch is stopped; it can then be reset to its starting 

value by tapping the  or  keys on the right 

touch pad at the same time (CLEAR).
140 Detail program description - Control adjust

 Switching between "forwards" and "backwards"

Timer runs forwards (stopwatch function)

Following switch assignment, if the stopwatch shown on 

the basic display is started with the initial value of "0:00", 

then it will run forwards for max. 180 min and 59 s and 

then restart from 0:00.

 Timer runs backwards (countdown function)

In the – left – minutes fi eld, select a start time between 0 

and 180 min ...

Timer

12:34h –––

1:23h

0:00

180:00

SEL

Model time

Batt. time

Top :

Centr:

Stop

Flight

... and in the – right – seconds fi eld, select a start time 

between 0 and 59 s (or any combination of these):

Timer

12:34h –––

1:23h

180:59

0:00

SEL

Model time

Batt. time

Top :

Centr:

Stop

Flight

Procedure

1. Select the desired input fi eld using the arrow keys 

 on the left or right touch pad.

2. Now tap SET in the center of the right touch pad.

3. Make your time selection in the highlighted minutes 

or seconds fi eld, using the arrow keys on the right 

touch pad.

4. Complete your input by tapping the center SET key.

5. If you tap the  or  keys on the right touch 

pad at the same time (CLEAR), this will reset any 

settings made back to "0" or "00".

6. After switching back to the basic display (by tapping 

the center ESC key on the left touch pad as many 

times as required), make sure the stopwatch is 

stopped and then tap the  or  keys on 

the right touch pad (CLEAR) so that the stopwatch 

switches over to the "timer" function. Look to the top 

right in the following screen image:

GRAUBELE

#01

0:00h

Stop

Flt

K78

10:01

0:00

0.0V

5.9V

M

HoTT

After the assigned switch is activated, the stopwatch 

starts at the initial value set and runs backwards

("countdown function"). Once the timer reaches zero it 

does not stop, but continues to run to enable you to read 

off the time elapsed after it reached 0:00. To make this 

absolutely clear, the timer is shown highlighted.

 "Alarm" timer

The "Alarm" column is accessed by using the arrow 

key  on the left or right touch pad to move the marker 

frame over the "Timer column to the right. In the 

"Alarm" column, you can defi ne a time between 5 and 

90 seconds (in 5-second increments) before zero is 

reached: at this point an audible signal will be emitted, 

which eliminates the need for you to check the screen 

continually during the fl ight.

Alarm

12:34h –––

1:23h

0s

–––

–––

SEL

0s

Model time

Batt. time

Top :

Centr:

Stop

Flight

If you tap the  or  keys on the right touch pad 

at the same time (CLEAR), this will reset any settings 

made back to "0 s".

Audible signal sequence

30 s before zero: Triple beep

 Single beep every two seconds 

20 s before zero: Double beep

 Single beep every two seconds 

10 s before zero: Single beep

 Single beep every second

 5 s before zero: Single, higher-frequency beep 

every second

 Zero: Extended audible signal and 

screen switches to highlighted 

display

 Resetting timers when stopped

Tapping the  keys on the right touch pad at 

the same time (CLEAR) will reset the display of 

previously stopped timers on the basic display.

Notes:

• Timers that are running backwards are shown on the 

basic display with a fl ashing colon (:) between the 

minutes and the seconds fi elds.

• A typical application, "Timer activation via the C1 

joystick", can be found on page 252).
Detail program description - Control adjust 141

• If you change timer functionality, these changes are 

made active by pausing the timer(s) and then tapping 

the  or  keys on the right touch pad at the 

same time (CLEAR) to reset them.

• Remember that the timer switches also remain active 

during programming. 

• On the basic display, simultaneously tapping the

 or  keys on the right touch pad at the same 

time (CLEAR) will reset the previously stopped timer 

to its programmed initial value – see the "Alarm" 

timer section. 
142 Detail program description - Control adjust

 Fl. phase timers

Selecting and setting

The discussion of the "Phase settings" menu on page 

134 has already described how timers can be assigned 

to a fl ight phase. The same section has also described 

the properties of "Time1" and "Time2". This section 

now proceeds to describe "Clk 1, 2 and 3", plus the "lap 

counter/timetable" timer.

The additional, fl ight phase-specifi c timer selected is 

displayed on the basic display underneath the "center" 

timer, as shown below:

GRAUBELE

#01

2:22h

Stop

Flt

«Speed »

K78

0:00

0:00

5.5V

5.2V HoTT

M

Clk1 0:00

In this menu ... 

Non-delayed chan

Timers (general)

Wing mixers

Free mixers

MIX active/phase

Fl. phase timers

Non-delayed chan

Timers (general)

Helicopter mixer

Free mixers

MIX active/phase

Fl. phase timers

 ... you can now program "Clks 1 ... 3" as stopwatches 

(i. e. timers that run forward) or as countdown/alarm 

timers (i. e. timers that run backwards). You can assign 

any switch to these timers, and the same is true of the 

"lap counter/timetable" timer:

Timer1

Timer2

Timer3

Lap time/tim tab

SEL

0:00 –––

0:00

0:00

Lap Display

0s

0s

0s

–––

–––

–––

–––

SEL

The fl ight phase timers "Clks 1 ... 3" and the 

"Time1"/"Time2" timers (described in the "Phase 

settings" section, pp. 128 and 132) run only in the fl ight 

phase to which they have been assigned. They are also 

shown as appropriate on the basic display. During other 

fl ight phases they are stopped (and hidden) and the 

assigned stop/start switch then has no effect.

The lap counter, once started, continues to run through 

changes of phase (as discussed further below), 

however, although it can be stopped during any fl ight 

phase via the center ESC key on the left touch pad.

 Clks 1, 2 and 3

These timers are started and stopped via a switch or 

control switch. To do so, fi rst use the arrow keys to select 

the appropriate column via the switch icon at the bottom 

right. Then set the switch that you want by briefl y tapping 

the center SET key on the right touch pad, as described 

in the section "Assigning transmitter controls, switches 

and control switches" (p. 52). Here, too, a control switch 

offers you the option of activating the timer via one 

of the joysticks or proportional rotary controls. The 

switching point along the transmitter control travel is set 

on the "Control switch" menu (page 123).

Remember that the timer switches also remain active in 

programming mode.

 Switching between "forwards" and "backwards"

 Stopwatch mode (timer runs forwards) 

In this mode, the timer starts at the initial value "0:00" 

(min:sec) when you operate the assigned switch. If it 

reaches the maximum time of 180 min. and 59 s, it will 

re-start at "0:00".

 "Countdown" (timer runs backwards)

Following the activation of the corresponding value fi elds 

(by tapping the center SET key on the right touch pad), 

if a time in minutes (maximum 180 min) and/or a time 

in seconds (maximum 59 s, right fi eld) is set, then the 

timers will run backwards from this initial value following 

the activation of the assigned switch (see section 

"Assigning transmitter controls, switches and control 

switches" on page 52), i.e. a "countdown" function will 

apply. Once the timer reaches zero it does not stop, 

however, but continues to run (highlighted) so you can 

read off the time elapsed after reaching zero.

Note:

Timers that are running backwards are shown on the 

basic display with a fl ashing colon (:) between the 

minutes and the seconds fi elds.

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the values entered in 

the currently active fi eld to zero.
Detail program description - Control adjust 143

 Alarm timer

SEL

0:00 –––

0:00

0:00

0s

0s

–––

–––

–––

–––

SEL

Timer1 0s

Timer2

Timer3

Lap time/tim tab

Lap Display

The input fi eld in the "Alarm" column is activated by 

tapping the center SET key on the right touch pad. In 

this fi eld, use the arrow keys on the left or right touch 

pad to defi ne a time between 5 and 90 seconds (in 

5-second increments) before zero is reached: at this 

point an audible signal will be emitted, which eliminates 

the need for you to check the screen continually during 

the fl ight. 

Audible signal sequence

30 s before zero: Triple beep

Single beep every two seconds 

20 s before zero: Double beep

Single beep every two seconds 

10 s before zero: Single beep|

Single beep every second

 5 s before zero: Single, higher-frequency beep 

every second

 Zero: Extended audible signal and 

screen switches to highlighted 

display

Tapping the  or  keys on the right touch pad at 

the same time (CLEAR) will reset the values entered in 

the currently active fi eld to "0s".

Note:

If timer functionality has been changed at any point, then 

the new changes to settings are made active only after 

the timer(s) have been stopped on the basic display and 

by then tapping the  or  keys on the right touch 

pad at the same time (CLEAR) to reset them.

Like the two standard timers positioned above it, this 

third, phase-specifi c timer is reset to its starting value 

by simultaneously tapping the  or  keys on 

the right touch pad (CLEAR). It is stopped in all fl ight 

phases at the same time, even if it has not been stopped 

separately in the other fl ight phases.

 Lap counter/timetable

SEL

0:00 –––

0:00

0:00

0s

0s

–––

–––

–––

–––

SEL

Timer1 0s

Timer2

Timer3

Lap time/tim tab

Lap Display

On the "Lap time/tim tab" line, assign a switch only 

as described in the section "Assigning transmitter 

controls, switches and control switches" (page 52). 

Preferably, you should make use of one of the two 

momentary switches (SW 1 or 9) at this point: in this 

way, the lap count is incremented each time by one lap 

while simultaneously (and automatically) the lap time 

elapsed during this lap is stopped (and recorded). This 

momentary switch simultaneously starts the stopwatch 

for the next lap. As the timer is triggered, the lap or 

switch impulse counter is shown highlighted.

GRAUBELE

#01

2:22h

Stop

Flt

«Speed »

K78

0:00

0:00

5.5V

5.2V 0:00.0

M

Lap

2:33.4

11

"Time1" and "Time2" operate in the same manner; for 

more details please read the section on the "Phase 

settings" menu option.

Up to 99 lap times can be recorded and accessed, 

each with a maximum duration of 99 minutes and 

59.9 seconds.

To stop the timer in question, tap the center ESC key on 

the left touch pad on the basic display after the fl ight is 

over. The lap or switch impulse counter is now shown in 

"normal" mode:

GRAUBELE

#01

2:22h

Stop

Flt

«Speed »

K78

0:00

0:00

5.5V

5.2V 0:00.0

M

Lap

4:33.2

22

If you tap the  or  keys on the right touch pad 

at the same time (CLEAR), this resets the counter to 

"00" and deletes the stored times. However, the timers 

must have been stopped before this.

Notes:

• If you have selected a normal switch to operate the 

lap counter, take care to ensure that this switch is set 

to "OFF" before you press the center ESC button on 

the left touch pad.
144 Detail program description - Control adjust

• If you should forget to switch off the lap counter in a 

phase which is now not currently active, simply press 

the center ESC button on the left touch pad.

To swap between the basic display and the "Lap 

Display" ...

01

02

03

04

SEL

01:23.4

02:34.5

03:45.6

05

SEL

04:56.7

05:67.8

07

08

09

10

00:00.0

00:00.0

00:00.0

11

12

00:00.0

00:00.0

06 06:78.9 00:00.0

... go to the line ...

 Lap Display

SEL

0:00 –––

0:00

0:00

0s

0s

–––

–––

–––

–––

SEL

Timer1 0s

Timer2

Timer3

Lap time/tim tab

Lap Display

... and use the switch assigned. You assign this switch 

as described in the section "Assigning transmitter 

controls, switches and control switches" (page 52).
Detail program description - Control adjust 145

 What is a mixer?

Basic functionality

With many models, a mix of the model's functions 

is often desirable, i. e. coupling aileron to rudder or 

coupling two servos together, in cases where rudder 

control surfaces with the same functionality are to be 

controlled together using a single servo. In all cases, 

the signal fl ow at the "output" of the control function on 

the transmitter control side "branches" – i. e. also "after" 

transmitter control options such as e. g. "Dual Rate / 

Expo", "Control adjust", "Channel 1 curve", etc. – in 

order for the signal to have its predefi ned effect on 

the "input" of a different control channel and thus on a 

further receiver output.

Example: V-tail mixer

3 3

4

Servo 4,8 V C 577

Best.-Nr. 4101

Servo 4,8 V C 577

Best.-Nr. 4101

4

V-tail mixer

Control function inputs

Control channels

(receiver outputs)

Elevator stick

Rudder stick

Right rudder / elevator

Left rudder / elevator

Rudder

Elevator

Elevator

Rudder

Rudder

Elevator

The mx-20 HoTT transmitter software contains a 

large number of pre-programmed coupling functions as 

standard, which are designed to mix together two (or 

more) control channels. Accordingly, the mixer named in 

the example just above can be activated in the "Tail" line 

of the "Model type" menu by selecting "V-tail".

In addition, for each model memory in the fi xed-wing 

and heli programs, the software makes available a total 

of eight freely programmable linear mixers, four freely 

programmable curve mixers and four dual mixers.

Also ensure you read the general remarks on "free 

mixers" in this handbook (p. 180).
146 Detail program description - Control adjust

"MIX-only channel" (see page 193) and use it for 

another purpose with the help of a "free mixer" (see 

page 190).

• If you set "2AIL" on the "Model type" menu (page 

82), then the fl ight phase-dependent fl ap functionality 

can be achieved by making appropriate offset 

settings for input 5 on the "Control adjust" menu 

(page 96).

• For almost any menu option, you have the option 

of checking your settings by switching to the servo 

display screen, which is accessed by simultaneously 

tapping the arrow keys  on the left touch pad. 

Caution:

The vertical lines on the "Servo display" move in 

the same direction for ailerons and in the opposite 

direction for fl aps.

• Note that if two fl ap servos have been selected, 

any transmitter control assigned to input 7 will be 

decoupled in the software in order to avoid errors in 

operating the fl aps. The same applies to input 10 and 

the selection "2AIL 4FL".

• A range of options are available for positioning fl aps. 

You can ...

a) ... simply accept one position per fl ight phase, by 

setting only the corresponding trim values. 

b) ... vary the fl aps positioned as at a) by using any 

transmitter control, assigned to "Input 6" on the 

"Control adjust" menu (page 96) – possibly also 

made fl ight phase-dependent by selecting "PH" in 

the "Type" column. Preferably, this should be one 

of the CTRL 6 ... 8 proportional rotary controls.

The selected transmitter control directly controls 

the two fl ap servos located on receiver outputs 6 

and 7 and, as required, also the two FL2 servos 

then the fl ight phase name, e. g. "Normal", will appear on 

the lower edge of the display:

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

EL AI 0% 0%

–––

–––

RU

Normal

All options can then also be programmed specifi c to a 

fl ight phase.

Comments:

• Using the menu "Model type" (page 82), control 

of the airbrake mixers can be reprogrammed from 

control input 1 to 7 or 8 to 9, and the associated 

offset point can also be set.

• If you wish to set up a "butterfl y" system, with the 

ailerons raised and the fl aps (if present) lowered, this 

is achieved by entering the appropriate settings on 

the "Butterfl y" line on the "Brake settings" sub-menu.

• If you would like to alternate between the C1 stick 

controlling an electric drive system and a butterfl y 

system, then you can use the options in the "Motor" 

column on the "Phase settings" menu – see the 

example on page 248.

• You can also use the opportunity to set switch times 

for a "soft" transition from fl ight phase to fl ight phase 

on the "Phase settings" menu (see page 128).

• If your model features multiple wing fl aps and a 

"crow / butterfl y system" (see below), but without 

additional airbrakes, then you can separate output 

1 (usually freed up by the above system) from 

control function input 1 (throttle/brake stick) on the 

 Wing mixers

Calibrating the wing fl ap system

Within the menu tree of the menu ...

Free mixers

MIX active/phase

Fl. phase timers

Wing mixers

MIX-only channel

Dual mixer

... the sub-menus and options available depend entirely 

on the number of aileron and fl ap servos set up on the 

"Model type" menu (page 82) ... 

Tail type

Motor at C1

Normal

None

Aile/flaps 2AIL

M O D E L T Y P E

Brake Off 1 +100% In

SEL

... which means that the only settings listed are the 

ones that can actually be confi gured. This not only 

makes the menu more compact but also avoids potential 

programming errors.

With a preset of e. g. "2AIL" (no fl aps), the "Wing 

mixers" menu will be shown as follows:

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

EL AI 0% 0%

–––

–––

RU

normal

If you have confi gured several fl ight phases on the 

menus "Phase settings" (page 128) and "Phase 

assignment" (page 134), and assigned these names, 
Detail program description - Control adjust 147

connected to outputs 9 and 10 – assuming that 

corresponding fl aps have been specifi ed on the 

"Aile/fl aps" line on the "Model type" menu. This 

transmitter control indirectly controls the fl ap 

position of the ailerons via the percentage value 

entered in the "Ail" (and "Ail2") column on the 

"FLAP" line of the multi-fl ap menu.

 To be able to provide more fi ne-grained control of 

fl ap positions, however, you should reduce travel 

to about 25% on the "Input 6" line of the "Control 

adjust" menu.

c) ... alternatively, you can also leave the default 

entry of "0%" in the "Ail" (and "Ail2") column on 

the "FLAP" line of the multi-fl ap menu, and use 

the "Control adjust" menu to assign both input 

6 and input 5 to the same transmitter control. You 

can then set the degree to which both fl ap pairs 

are affected – optionally making this fl ight phasedependent by selecting "PH" in the "Type" column 

– with the respective travel adjustment.

 Basic programming procedure

1. Select the desired line by using the arrow keys 

on the left or right touch pad.

Depending on the line selected, the bottom line of the 

display will either show the "Next page" icon ( ) or 

a switch icon.

2. Depending on the line selected, you will either switch 

to the next page – on which you carry out the same 

procedure as below – or the desired value fi eld is 

activated by tapping the center SET key on the right 

touch pad.

3. Use the arrow keys to set the mixer ratio or degree of 

differential.

Accordingly, specify the input 1, 7, 8 or 9 and the offset 

corresponding to your customary piloting in the "Brake 

offset" line on the "Model type" menu – see page 82. 

When selecting "input 1", please note also that you 

may need to specify your desired "Throttle min" position 

"forward/back" before establishing the offset point in the 

"Motor at C1" line.

Note:

If the offset is not set right at the end of the transmitter 

travel, the rest of the travel is a "dead zone", i. e. the 

transmitter control does not infl uence any mixers on the 

"Brake settings" sub-menu. Otherwise, the mixer travel is 

expanded back to 100% automatically.

All other mixers on the "Wing mixers" menu have their 

neutral point with the control at its center, i. e. they have 

no effect at this control position. The value set is mixed 

in at full travel.

To confi gure symmetrical mixer values, move the 

transmitter control or joystick to its center position, so 

that the marker frame surrounds both value fi elds. To 

confi gure asymmetric values, move the transmitter 

control/joystick to the corresponding side.

Negative and positive parameter values are possible, 

in order to be able to adjust the respective function to 

the direction of servo rotation or fl ap orientation.

4. Tapping the  or  keys on the right touch 

pad at the same time (CLEAR) will reset the values 

entered in the currently active (highlighted) fi eld to 

the default value.

5. Complete your input by tapping the center ESC key 

on the left touch pad or the center SET key on the 

right touch pad.

 Assigning switches

The wing mixers "AI  RU" and "FL  EL" can be 

optionally switched on and off by using a switch or 

an expanded switch. Accordingly, when selecting the 

respective line, the familiar switch icon ( ) appears on 

the lower edge of the screen.

 Switching delays

The delay time or switch time confi gured on the menu 

"Phase settings" (page 128) for the respective fl ight 

phase also affects all wing mixers and thus avoids 

abrupt changes to fl ap confi gurations when switching 

between the fl ight phases.

 Mixer neutral points (offset)

For all mixers on the "Brake settings" submenu, the 

"brake offset" to be set on the "Model type" menu is to 

be confi gured to the transmitter control position at which 

the airbrakes are retracted. 
148 Detail program description - Control adjust

defl ection also generates drag and therefore further 

reduces the aircraft's effi ciency. 

If, on the other hand, a differential is applied to the 

aileron orientations, by giving the aileron oriented 

downwards a smaller defl ection than the aileron 

oriented upwards, the (undesirable) adverse yaw can 

be reduced – and possibly entirely negated. However, 

the basic precondition for this is that each aileron must 

have its own servo present, which can therefore also 

be embedded straight into the aerofoils. In addition, the 

shorter linkage paths produce an additional benefi t: 

reproducible aileron confi gurations that also exhibit less 

"play".

0% (normal)

50% (differential)

100% (split)

Unlike mechanical solutions, which not only commonly 

need to be designed and built in when constructing 

the model but also produce a slightly increased "play" 

in the control system for strong differentials, the 

transmitter-based differential typically used today offers 

considerable benefi ts.

The degree of differential can be changed at any 

time, for example, and, in extreme circumstances, the 

downward defl ection of an aileron – in what is termed 

a "split" position – can be suppressed entirely. This 

approach not only reduces or even suppresses "adverse 

yaw", but can, in certain circumstances, even generate 

a positive yaw: in such cases, an aileron command will 

generate a yaw about the vertical axis in the direction 

of the turn. For large glider models in particular, this 

approach lets such aircraft fl y "clean" turns using just 

the ailerons, which is not otherwise possible unaided.

The adjustment range of -100% to +100% makes it 

possible to set a differential appropriate for each side, 

regardless of the direction of rotation of the aileron 

servos. While "0%" corresponds to a normal linkage, i. e. 

no differential, "-100%" or "+100%" represents the "split" 

function. 

For aerobatic fl ying, low absolute values are required to 

ensure the model rotates exactly along its longitudinal 

axis when an aileron command is given. Values near 

to the center (-50% or +50%) are typical for facilitating 

turns in thermals. The split setting (-100%, +100%) is 

popular with slope fl yers, where ailerons alone are often 

used for turning the model.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

Note:

Negative values are not usually necessary if channels 

are assigned properly.

 Mixer functions

The individual options on the "Wing mixers" menu 

option are discussed below, separately for single-, dualand multi-fl ap models. Before we start, a number of 

remarks on the differentials for ailerons and fl aps:

 Aile. diff. or Diff. ( Aileron differential)

0%

0% 0%

–––

–––

Normal

Aile.diff. 0%

Brake settings

AI

WING MIXERS

EL AI

RU

fl.pos 0%

AILE

Normal

Diff.

AiI-tr

AI +100%

+100%

0%

For aerodynamic reasons, the drag generated on 

an aileron oriented downwards is greater than that 

generated by the same aileron when it is oriented 

upwards by the same amount. One effect of this unequal 

distribution of drag produces is a yawing motion around 

the vertical axis and, accordingly, a "turning away" 

from the intended direction of fl ight, which is why this 

undesirable side effect is also termed "adverse yaw". 

This effect is naturally greater on the comparably long 

aerofoils possessed by model gliders, compared to e. g. 

powered aircraft models, which generally have relatively 

short moment arms. For the former, it must normally 

be compensated for by making a simultaneous rudder 

defl ection in the opposite direction. However, this rudder 
Detail program description - Control adjust 149

 Diff. (camber-changing fl ap differential)

fl.pos 0%

FLAP

Normal

Diff.

Ail-tr

AI 0%

0%

0%

0%

FLAP2

0%

0%

0%

fl.pos

Normal

Diff.

Ail-tr

AI

In the "AI" line on the multi-fl ap menu, you can set 

the extent to which the fl aps act as ailerons and follow the 

aileron joystick; the value is entered as a percentage. The 

fl aps differential – to be set on the line "Diff." (two lines 

below) – works in a similar way to the aileron differential, 

i.e. where an aileron command acts on the fl aps, the 

respective defl ection downwards can be reduced.

The adjustment range of -100% to +100% makes it possible 

to set a differential appropriate for each side, regardless 

of the direction of rotation of the servos. A value of 0% is 

equal to normal linkage, i. e. the servo travel downwards is 

the same as the travel upwards. A value of -100% to +100% 

means that travel downwards will be reduced to zero for 

aileron commands affecting the fl aps ("split" mode). 

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

Note:

Negative values are not usually necessary if channels 

are assigned properly.

exception of a "pointer" to the "Elevat curve" sub-menu. 

Accordingly, we proceed immediately further from here 

by once again tapping the center SET key on the right 

touch pad:

Input

Output

Point ?

–100%

0%

0%

Brake

normal

Ele

Curve off

Normal

If required, i. e. if you have the feeling that you will need 

to set pitch trim compensation when the airbrakes are 

extended, you can program an appropriate automatic 

mixer affecting the elevator at this point. 

For detailed instructions on setting a curve mixer, please 

refer to menu option "Channel 1 curve" (page 116 

onwards).

 Aileron  Rudder

Brake settings

AI 0%

WING MIXERS

RU –––

Normal

Here, you can set the degree to which the rudder follows 

commands acting on ailerons. This is used in particular 

in connection with aileron differential to suppress 

adverse yaw and thus make it easier to fl y "clean" 

curves. You can of course still issue separate commands 

to the rudder. 

The adjustment range of ±150% lets you set the 

 Model type: "1AIL"

If you have entered "1AIL" for the "Aile/fl aps" line on the 

"Model type" menu (page 82 ), then the "Wing mixers 

menu" on your transmitter will match the following 

screen image:

Brake settings

AI 0%

WING MIXERS

RU –––

Normal

From the fi rst line on this display screen, you can switch 

to the sub-menu by briefl y tapping the center SET key 

on the right touch pad ...

 Brake settings

Note:

The "Brake settings" menu is switched "off" if you 

entered "Motor on C1 forward / back" on the "Model 

type" menu (see page 82), and entered "Yes" for the 

currently active fl ight phase in the "Motor" column of the 

"Phase settings" menu (see page 128). Switch the fl ight 

phase if required:

Elevat curve

BRAKE SETTINGS

normal

Normal

Since you cannot set up a butterfl y or aileron differential 

in a model with only a single aileron servo, this 

menu offers no further confi guration options with the 
150 Detail program description - Control adjust

 Model type: "1AIL 1FL"

If you have entered "1AIL 1FL" for the "Aile/fl aps" 

line on the "Model type" menu (page 82), then the 

"Wing mixers menu" on your transmitter will match the 

following screen image:

Brake settings

AI 0%

WING MIXERS

EL FL 0% 0%

–––

–––

RU

Normal

FL EL 0% 0% –––

From the fi rst line on this display screen, you can switch 

to the sub-menu by briefl y tapping the center SET key 

on the right touch pad ...

 Brake settings

Note:

The "Brake settings" menu is switched "off" if you 

entered "Motor on C1 forward / back" on the "Model 

type" menu (see page 82), and entered "Yes" for the 

currently active fl ight phase in the "Motor" column of the 

"Phase settings" menu (see page 128). Switch the fl ight 

phase if required:

Elevat curve

BRAKE SETTINGS

Crow

Normal

0%

FLAP

Appropriate to the model type selected, you can now 

enter a suitable value in the "Crow" line to lower the fl ap 

when you activate the brake control – which is typically 

the C1 joystick.

To confi gure the setting, fi rst position the brake control in 

the brake position at full travel (i.e. its end-point). Then, 

briefl y tap the center SET key on the right touch pad and 

enter a suitable value using the arrow keys on the left or 

right touch pad. To ensure a suffi ciently strong braking 

effect, note that you should try to lower the fl ap as low 

as is mechanically possible.

From the second line on this display screen, you can 

switch to the sub-menu "Elevat curve" by briefl y tapping 

the center SET key on the right touch pad:

Input

Output

Point ?

–100%

0%

0%

Brake

normal

Ele

Curve off

Normal

If required, i. e. if you have the feeling that you will need 

to set pitch trim compensation when the airbrakes are 

extended, you can program an appropriate automatic 

mixer affecting the elevator at this point. 

For detailed instructions on setting a curve mixer, please 

refer to menu option "Channel 1 curve" (page 116 

onwards).

 Aileron  Rudder

Brake settings

AI 0%

WING MIXERS

EL FL 0% 0%

–––

–––

RU

Normal

FL EL 0% 0% –––

direction of defl ection as appropriate. Optionally, this 

mixer can be activated and deactivated by using one of 

the switches that do not reset themselves (SW 2 ... 8) or 

a control switch. This means you can then also control 

the model using only the ailerons or rudder, as required. 

Typically, this mixer is set so that the rudder is defl ected 

to the same side as the upward-oriented aileron, and 

you will fi nd that setting a value of around 50% is usually 

highly appropriate. 

Settings are always made symmetrically relative to the 

neutral point of the aileron joystick. 

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.
Detail program description - Control adjust 151

Here, you can set the degree to which the rudder follows 

commands acting on ailerons. This is used in particular 

in connection with aileron differential to suppress 

adverse yaw and thus make it easier to fl y "clean" 

curves. You can of course still issue separate commands 

to the rudder. 

The adjustment range of ± 150% lets you set the 

direction of defl ection as appropriate. Optionally, this 

mixer can be activated and deactivated by using one of 

the switches that do not reset themselves (SW 2 ... 8) or 

a control switch. This means you can then also control 

the model using only the ailerons or rudder, as required. 

Typically, this mixer is set so that the rudder is defl ected 

to the same side as the upward-oriented aileron, and 

you will fi nd that setting a value of around 50% is usually 

highly appropriate.

Settings are always made symmetrically relative to the 

neutral point of the aileron joystick.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

 Elevator  fl aps

Brake settings

AI 0%

WING MIXERS

EL FL 0% 0%

–––

–––

RU

Normal

FL EL 0% 0% –––

To provide support for the elevator for tight turns 

and aerobatics, this mixer can be used to make the 

fl ap function follow controls sent to the elevator. The 

mixer direction chosen must ensure that the fl aps are 

defl ected downwards when the elevator is oriented 

upwards and vice versa for a downward-oriented 

elevator – i.e. in opposite directions. Optionally, this 

mixer can be activated and deactivated by using one of 

the switches that do not reset themselves (SW 2 ... 8) or 

a control switch.

To confi gure symmetrical mixer values, move 

the elevator joystick to its center position, so that 

the marker frame surrounds both value fi elds. To 

confi gure asymmetric values, move the joystick to the 

corresponding side.

Values in the range -150% to +150 are possible, so as 

to adjust the function to the direction of servo rotation or 

direction of fl ap defl ection.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

The "typical" values confi gured for this mixer are singledigit or low two-digit values.

 Flaps  elevator

Brake settings

AI 0%

WING MIXERS

EL FL 0% 0%

–––

–––

RU

Normal

FL EL 0% 0% –––

This mixer is used to set elevator (pitch-trim) 

compensation when a fl ap command is given. This 

typically enables you to adjust the model's airspeed 

automatically when fl aps are lowered. 

If you have used the "Control adjust" menu (page 96) 

to assign input 6 a transmitter control or switch – 

possibly fl ight phase-dependent – then this also affects 

this mixer.

Depending on the position of the fl ap control, either 

a symmetrical or asymmetric setting within the range 

±150% is possible.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

If required, the mixer can be switched on or off by 

assigning a switch in the right column.

The values confi gured for this mixer are typically in the 

single-digit range.
152 Detail program description - Control adjust

 Model type: "2AIL"

If you have entered "2AIL" for the "Aile/fl aps" line on the 

"Model type" menu (page 82), then the "Wing mixers 

menu" on your transmitter will match the following 

screen image:

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

EL AI 0% 0%

–––

–––

RU

Normal

From the fi rst line on this display screen, you can switch 

to the sub-menu by briefl y tapping the center SET key 

on the right touch pad ...

 Brake settings

Note:

The "Brake settings" menu is switched "off" if you 

entered "Motor on C1 forward / back" on the "Model 

type" menu (see page 82), and entered "Yes" for the 

currently active fl ight phase in the "Motor" column of the 

"Phase settings" menu (see page 128). Switch the fl ight 

phase if required:

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red

0%

0%

0% 0%

0% 0%

WK WK2

Normal

Depending on the model type selected, you will now 

have appropriate confi guration options available in 

the lines "Crow" and "D(ifferential) red(uction)" for the 

"AILE" column. You should utilize these options by ...

• ... moving the transmitter control for "Brake" 

(see description for "Model type" menu on page 

82 – typically the C1 joystick – to its braking end-point. 

Then switch to the "Crow" line, briefl y tap the center 

SET key on the right touch pad and use the arrow 

keys on the left or right touch pad to set a value that 

moves the aileron upwards as far as possible to 

brake the model, or – if you are using airbrakes as 

the main braking system – the aileron should be set 

to elevate only minimally to provide an extra braking 

effect.

Note:

To reliably prevent the servos mechanically striking 

their end-stops – which draws a heavy current – you 

can set an appropriate limit value in the "– lim +" 

column of the "Servo adjustments" menu (page 90).

• ... then, fi nally, moving to the "D. red" line and setting 

a % value that is greater than or equal to the "Aile.

diff." value that you set (or have yet to set) on the 

display page "before" this one.

In this way, you can suppress the aileron differential 

when braking, thus ensuring that you can count on 

suffi cient aileron response despite your ailerons 

being defl ected upwards.

From the lowest line, "Elevat. curve", you can switch to 

setting the "Elevat. curve" mixer by briefl y tapping the 

center SET key on the right touch pad:

Input

Output

Point ?

–100%

0%

0%

Brake

normal

Ele

Curve off

Normal

If required, i. e. if you have the feeling that you will need 

to set pitch trim compensation when the airbrakes are 

extended, you can program an appropriate automatic 

mixer affecting the elevator at this point. 

For detailed instructions on setting a curve mixer, please 

refer to menu option "Channel 1 curve" (page 116 

onwards).

 Aileron differential

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

EL AI 0% 0%

–––

–––

RU

Normal

The adjustment range of ±100% makes it possible to 

set the correct direction of differential, regardless of the 

direction of rotation of the aileron servos. While "0%" 

corresponds to a normal linkage, i. e. no differential on 

the transmitter, "-100%" or "+100%" represents the 

"split" function.

For aerobatic fl ying, low absolute values are required to 

ensure the model rotates exactly along its longitudinal 

axis when an aileron command is given. Values near 

to the center (-50% or +50%) are typical for facilitating 

turns in thermals. The split setting (-100%, +100%) is 
Detail program description - Control adjust 153

popular with slope fl yers, where ailerons alone are often 

used for turning the model.

0% (normal)

50% (differential)

100% (split)

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

Note:

Negative values are not usually necessary if channels 

are assigned properly.

 Aileron  rudder

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

EL AI 0% 0%

–––

–––

RU

Normal

Here, you can set the degree to which the rudder follows 

commands acting on ailerons. This is used in particular 

in connection with aileron differential to suppress 

adverse yaw and thus make it easier to fl y "clean" 

curves. You can of course still issue separate commands 

to the rudder. 

The adjustment range of ± 150% lets you set the 

direction of defl ection as appropriate. Optionally, this 

mixer can be activated and deactivated by using one of 

the switches that do not reset themselves (SW 2 ... 8) or 

a control switch. This means you can then also control 

the model using only the ailerons or rudder, as required. 

Typically, this mixer is set so that the rudder is defl ected 

to the same side as the upward-oriented aileron, and 

you will fi nd that setting a value of around 50% is usually 

highly appropriate.

Settings are always made symmetrically relative to the 

neutral point of the aileron joystick.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

 Elevator  aileron

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

EL AI 0% 0%

–––

–––

RU

Normal

To provide support for the elevator for tight turns 

and aerobatics, this mixer can be used to make the 

aileron function follow controls sent to the elevator. The 

mixer direction chosen must ensure that the fl aps are 

defl ected downwards when the elevator is oriented 

upwards and vice versa for a downward-oriented 

elevator – i.e. in opposite directions. Optionally, this 

mixer can be activated and deactivated by using one of 

the switches that do not reset themselves (SW 2 ... 8) or 

a control switch.

To confi gure symmetrical mixer values, move the 

elevator joystick to its center position, so that the 

marker frame surrounds both value fi elds. To confi gure 

asymmetric values, move the transmitter control to the 

corresponding side.

Values in the range -150% to +150 are possible, so as 

to adjust the function to the direction of servo rotation or 

direction of aileron defl ection.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

The "usual" values for this mixer are in the low two-digit 

range.
154 Detail program description - Control adjust

 Model type: "2/4AIL 1/2/4FL"

If you have entered "2AIL 1FL" for the "Aile/fl aps" 

line on the "Model type" menu (page 82), then the 

"Wing mixers menu" on your transmitter will match the 

following screen image:

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

FL EL 0% 0%

–––

–––

RU

Multi-flap menu

Normal

If, on the other hand, you have entered "2/4AIL 

1/2/4FL" for the "Aile/fl aps" line on the "Model type" 

menu (page 82), then the "Wing mixers menu" on your 

transmitter will show the following:

0%

0% 0%

–––

–––

Brake settings

AI

WING MIXERS

FL EL

RU

Multi-flap menu

Normal

Regardless of the combination of aileron and fl ap servos 

you choose, all of the parameters available can be 

adjusted separately for each fl ight phase.

Note:

For almost any menu option, you have the option of 

checking your settings by switching to the servo display 

screen, which is accessed by simultaneously tapping 

the arrow keys  on the left touch pad. If you do, note 

however that the vertical lines on the "Servo display" 

move in the same direction for ailerons and in the 

opposite direction for fl aps.

Before we address the details of this menu we would 

like to provide a brief explanation of the different display 

modes for the multi-flap menu:

 Model type: "2 AIL 1 FL"

If you connect the servos to the receiver as described 

on page 57 and select them appropriately on the "Model 

type" menu (see page 82), then the abbreviations "AI" 

and "FL" refer to the following fl aps:

AI

left

FL FL AI

right

Since the options available on the wing mixer menu 

and its sub-menus vary according to the number of fl ap 

servos specifi ed on the "Model type" menu (page 82), 

the list contains only the set-up options that are possible 

for your model configuration.

FL

0%

0%

fl.pos

EL FL 0% 0%

0%

AILE

Normal

Accordingly, with values preset to "2AIL 1FL", the 

options to set aileron functions for fl aps will be hidden 

and it will be possible to move only one column to the 

right, into the column "FLAP": 

FL +100%

fl.pos

EL FL 0% 0%

+100%

FLAP

Normal

0%

In addition, the settings for "Aile(ron) diff(erential)" are 

not found on the "multi-fl ap menu", as with "2AIL 2/4FL", 

but one level higher in the "Wing mixers" menu – see the 

screen-shot at top left.

 Model type: "2AIL 2FL"

If you connect the servos to the receiver as described 

on page 57 and select them appropriately on the "Model 

type menu (see page 82), then the abbreviations "AI" 

and "FL" refer to the following fl aps:

AI

left

FL

left

FL

right

AI

right

Since the options available on the "wing mixer menu" 

and its sub-menus vary according to the number of fl ap 

servos specifi ed on the "Model type" menu (page 82), 

the list contains only the set-up options that are possible 

for your model configuration.

This means that if values are preset to "2AIL 2FL", then 

all confi guration options for the aileron pair ...
Detail program description - Control adjust 155

FL

0%

0%

fl.pos

EL FL 0% 0%

0%

AILE

Normal

Diff. 0%

Ail-tr

AI +100%

+100%

... are shown, and – one "step" to the right – all options 

for the fl ap pair as well:

0%

+100%

0% 0%

+100%

FLAP

0%

0%

0%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

Moving one further column to the right, however – to the 

"FLAP2" column – is not possible.

 Model type: "2AIL 4FL"

If you connect the servos to the receiver as described 

on page 57 and select them appropriately on the "Model 

type" menu (see page 82), then the abbreviations "AI", 

"FL" and "FL2" refer to the following fl aps:

AI

left

FL

left

FL2

left

FL2

right

FL

right

AI

right

Since the options available on the "wing mixer menu" 

and its sub-menus vary according to the number of fl ap 

servos specifi ed on the "Model type" menu (page 82 ), 

the list contains only the set-up options that are possible 

for your model configuration.

This means that if values are preset to "2AIL 4FL", then 

all confi guration options for the aileron pair ...

FL

0%

0%

fl.pos

EL FL 0% 0%

0%

AILE

Normal

Diff. 0%

Ail-tr

AI +100%

+100%

... are shown, and – one "step" to the right – all options 

for the fi rst fl ap pair ... 

0%

+100%

0% 0%

+100%

FLAP

0%

0%

0%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

... are shown, and – one further "step" to the right – all 

options for the second fl ap pair as well:

0%

+100%

0% 0%

+100%

FLAP2

0%

0%

0%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

 Model type: "4AIL 2FL"

If you connect the servos to the receiver as described 

on page 57 and select them appropriately on the "Model 

type" menu (see page 82), then the abbreviations "AI", 

"AI2" and "FL" refer to the following fl aps:

AI

left

AI2

left

FL

left

FL

right

AI2

right

AI

right

Since the options available on the "wing mixer menu" 

and its sub-menus vary according to the number of fl ap 

servos specifi ed on the "Model type" menu (page 82 ), 

the list contains only the set-up options that are possible 

for your model configuration.

This means that if values are preset to "4AIL 2FL", then 

all confi guration options for the fi rst aileron pair ...
156 Detail program description - Control adjust

FL

0%

0%

fl.pos

EL FL 0% 0%

0%

AILE

Normal

Diff. 0%

Ail-tr

AI +100%

+100%

... are shown, and – one "step" to the right – all options 

for the second aileron pair ...

0%

0%

0% 0%

0%

AILE2

0%

+100%

+100%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

... are shown, and – one further "step" to the right – all 

options for the fl ap pair as well:

0%

+100%

0% 0%

+100%

FLAP

0%

0%

0%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

 Model type: "4AIL 4FL"

If you connect the servos to the receiver as described 

on page 57 and select them appropriately on the "Model 

type" menu (see page 82), then the abbreviations "AI", 

"AI2", "FL" and "FL2" refer to the following fl aps:

AI

left

AI2

left

FL

left

FL2

left

FL2

right

FL

right

AI2

right

AI

right

Since selecting "4AIL 4FL" means choosing the 

maximum number of control surface servos, the 

columns "AILE" ... 

FL

0%

0%

fl.pos

EL FL 0% 0%

0%

AILE

Normal

Diff. 0%

Ail-tr

AI +100%

+100%

... and "AILE2" ...

0%

0%

0% 0%

0%

AILE2

0%

+100%

+100%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

... are supplemented by the columns "FLAP" ...

0%

+100%

0% 0%

+100%

FLAP

0%

0%

0%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

... and "FLAP2":

0%

+100%

0% 0%

+100%

FLAP2

0%

0%

0%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

 Delta/fl ying wing type models with more than two 

wing fl aps

If you have selected the "Delta/fl " tail type and selected 

the number of wing fl aps in the "Aile/fl aps" line on the 

"Model type" menu (following the instructions given 

in that section), then the two ailerons will normally not 

move when you move the elevator joystick – and the 

same will be true for the inner fl aps (FL) and FL2 (if 

present). The reason for this is the default mixer ratio of 

0% for all wing fl aps, set for the "EL  FL" mixer that is 

to be found on the multi-fl ap menu:
Detail program description - Control adjust 157

0%

0%

0% 0%

0%

AILE

0%

+100%

+100%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

Accordingly, you must fi rst specify your desired elevator 

control on the "EL  FL" line. Take care to ensure that 

up/down activation occurs in the right sequence.

Note:

The "Brake settings" sub-menu (see next double page) 

is also suitable for setting up the butterfl y (crow) function 

with delta and fl ying wing models. In fi ne-tuning the 

defl ection of the fl ap pairs AIL, FL and (if present) FL2, 

however, ensure that the moments created by one pair 

of fl aps compensate the moments created by the other 

pair of fl aps in each case. For example: the "up" effect of 

ailerons when defl ected up should be compensated by a 

"down" effect from fl aps when they are lowered. 

 Multi-fl ap menu

Important notice:

Depending on the fl ap pairs specifi ed in the "Model 

type" menu, this menu will present the column "AILE2" 

and/or the columns "FLAP" and "FLAP2" in addition 

to the "AILE" column. Since both the columns "AILE" 

and "AILE2" and the columns "FLAP" and "FLAP2" are 

identical except for the label shown at the bottom right, 

further display of the columns "AILE2" and "FLAP2" is 

avoided below for reasons of saving space.

AI (Aileron  fl aps)

(Not shown for "2AIL 1FL".)

0%

AILE

0%

+100%

+100%

fl.pos

Normal

Diff.

Ail-tr

AI

0%

FLAP

0%

0%

0%

fl.pos

Normal

Diff.

Ail-tr

AI

In the line "AI" you can set the percentage extent to 

which the wing fl ap pair "FLAP" (and, if present, "FL2") 

follow when an aileron command is given (the value 

can be entered separately for each fl ight phase). (In the 

"AILE" column it is also possible to adjust the defl ection 

of the aileron pair, if required.) Normally, however, the 

fl aps should follow the ailerons with less of a defl ection, 

i. e. the mixer ratio should be smaller than 100%. 

The adjustment range of -150% to +150% means the 

direction of defl ection can be adjusted, depending on 

the direction of rotation of the servos, to suit the ailerons.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to the 

default value (see screen image).

 Ail-tr. (aileron trim)

(Not shown for "2AIL 1FL".)

0%

AILE

0%

+100%

+100%

fl.pos

Normal

Diff.

Ail-tr

AI

0%

FLAP

0%

0%

0%

fl.pos

Normal

Diff.

Ail-tr

AI

In this line, you specify the percentage rate with which 

aileron trim is to affect "AILE", "FLAP" and – if present 

– "FLAP2".

The available range of values is -150% to +150%, 

relative to the adjustment range of the trim lever.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to the 

default value (see screen image).

 Diff. (Differential for aileron function)

(With "2AIL 1FL", found one level higher on the "Wing 

mixers" menu – see screen image on previous double 

page.)
158 Detail program description - Control adjust

0%

AILE

0%

+100%

+100%

fl.pos

Normal

Diff.

Ail-tr

AI

0%

FLAP

0%

0%

0%

fl.pos

Normal

Diff.

Ail-tr

AI

On this line, you set the aileron differential, plus the 

differential for the FLAP and FLAP2 wing fl aps – if the 

latter are being activated as ailerons.

0% (normal)

50% (differential)

100% (split)

AI FL FL2

FL2 FL AI

If you are unsure about the meaning of differential travel, 

please read the appropriate explanation at the start of 

this section on page 148.

The adjustment range of -100% to +100% makes 

it possible to set the correct direction of differential 

regardless of the direction of rotation of the aileron and 

fl ap servos.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to the 

default value (see screen image).

 fl .pos (wing fl ap position)

0%

AILE

0%

+100%

+100%

fl.pos

Normal

Diff.

Ail-tr

AI

0%

FLAP

0%

0%

0%

fl.pos

Normal

Diff.

Ail-tr

AI

Here, you set the fl ight phase-specifi c wing fl ap 

positions for all of the fl aps present on the model in 

question. In this way, you can specify the fl ap positions 

that apply to each fl ight phase. 

The adjustment range of -100% to +100% makes it 

possible to set the correct direction of travel regardless 

of the direction of rotation of the aileron and fl ap servos.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to the 

default value (see screen images).

FL (Effects of fl ap controls)

In this line, you specify the percentage rate with which 

the settings for input 6 (as made on the "Control 

adjust" menu, page96, and potentially dependent on 

fl ight phase) will affect the wing fl ap positions of the 

aileron and camber-changing fl aps.

0%

0% 0%

AILE

0%

+100%

FL

fl.pos

Normal

Diff.

Ail-tr

0%

+100% +100%

FLAP

0%

0%

FL

fl.pos

Normal

Diff.

Ail-tr

For each fl ap pair, you can defi ne either a symmetrical 

or an asymmetric effect. Position the transmitter control 

accordingly – either centrally or to the relevant side.

If you leave (or have left) each travel adjustment at 

+100% on the "Control adjust" menu (page 96), then 

values between 5% and 20% should generally be 

suffi cient.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to the 

default value (see screen images). 

Note:

By default, NO transmitter control is assigned to input 6 
Detail program description - Control adjust 159

on the "Control adjust" menu. However, you can assign 

a transmitter control or switch to this input at any time 

– also in a fl ight phase-dependent way – thus enabling 

different fl ap settings within a fl ight phase; see also 

example 2 on page 260.

 EL  FL (Elevator  fl aps) 

To provide support for the elevator for tights turns 

and aerobatics, this mixer can be used to make the 

fl ap function follow controls sent to the elevator. The 

mixer direction chosen must ensure that the fl aps are 

defl ected downwards when the elevator is oriented 

upwards and vice versa for a downward-oriented 

elevator – i.e. in opposite directions. 

For each fl ap pair, you can defi ne either a symmetrical 

or an asymmetric effect. Position the transmitter control 

accordingly – either centrally or to the relevant side. 

Values in the range -150% to +150% are possible:

0%

0%

0% 0%

0%

AILE

0%

FL

fl.pos

EL FL

Normal

Diff.

0%

+100%

0% 0%

+100%

FLAP

0%

FL

fl.pos

EL FL

Normal

Diff.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to the 

default value (see screen images). 

The "usual" values for this mixer are in the low two-digit 

range.

Important general notice:

Do not let control surfaces and servos strike their 

mechanical end-stops when large defl ections 

are set! This is especially relevant in relation to 

the functions "AI", "FL" and possibly 

"FL2". Use the "- lim +" option (travel limit) 

available on the "Servo adjustments" menu 

(page 90), as required. 

 Brake settings

Notes:

• The "Brake settings" menu is switched "off" if you 

entered "Motor on C1 forward / back" on the "Model 

type" menu (see page 82), and entered "Yes" for the 

currently active fl ight phase in the "Motor" column of 

the "Phase settings" menu (see page 128). Switch 

the fl ight phase if required:

• The "brake mixers" described below can also – 

and should also – be confi gured to be specifi c to 

individual fl ight phases.

 Crow

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red

0%

0%

0% 0%

0% 0%

FLAP FLAP2

Normal

The "Crow" mixer function is actuated by control function 

1, 7, 8 or 9, depending on the input that you have 

assigned on the "Brake Off" line on the "Model type" 

menu (see page 82).

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake off +90%

STO SEL

In 1

Note:

On the "Model type" menu (see page 82), you should 

also defi ne the offset, i. e. the direction of operation. 

The offset should be set to about +90% of stick travel 

(if the C1 stick is used, this is generally located at the 

forward position of the stick). To extend the fl aps, the 

stick must therefore be moved back towards the pilot. 

The remaining joystick travel of around 10% then has no 

effect, although it is not "lost", since the control travel is 

automatically expanded back to 100%.

Use the select fi elds for the AILE, FLAP and – if present 

– FL2 columns to defi ne the extent and direction to 

which the corresponding pairs of fl aps are to follow 

when the airbrake control (control function 1, 7, 8 or 

9) is operated. If the model does not feature separate 

airbrakes, leave the corresponding receiver output free 

or use the "MIX-only channel" menu to set this to "MIXonly", to be able to use it elsewhere.

Values in the range -150% to +150% are possible.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to the 

default value (see screen image). 
160 Detail program description - Control adjust

AI

FL

FL2

FL2

FL

AI

If the airbrake mixers are set as described above, then a 

special fl ap combination – also referred to as the "crow 

position" or "butterfl y" – can be confi gured: With this 

airbrake setting, both ailerons move moderately upwards

while the fl aps move as far as possible downwards. 

A further mixer – see below, under the section "Elevat 

curve" – is then used to trim the elevator in such a way that 

the model's airspeed changes very little compared to the 

normal fl ight position. Otherwise, there is a danger that the 

model loses too much speed and then, after the braking 

system is retracted (e. g. to extend a landing approach that 

was too short, for example), pancakes or even stalls.

A tip for "seeing" the effect of brakes:

lift the fl aps and look over and under the surface from 

the front. The larger the surface projected by the lifted 

fl ap, the greater the braking effect achieved.

Tips for activating airbrakes:

• If you have installed a servo for operating 

conventional wing-mounted airbrakes in addition to 

the aileron and fl ap servos, the simplest method of 

controlling it is to connect it to the receiver output 

whose input you have selected for the brake function, 

i. e. either 1, 7, 8 or 9 – assuming it it is free. If this is 

not possible, then as an alternative you can set a free 

mixer, which connects up the brake control channel 

you have selected with the airbrake servo channel. 

• To activate two airbrake servos, the best approach 

is to leave one servo on output 1 and to connect the 

second servo to a free output of your choice – for 

example, output 8. You then also assign this output 

to transmitter control 1 (as standard) on the "Control 

adjust" menu (page 96) – see screen image:

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

GL

GL

GL

GL

typ

normal

Ct1

As you do, leave the settings for offset, travel, etc. at 

their default values. Also leave the default value at 

"GL" in the "typ" column, since the second airbrake, 

like the fi rst, should be active in the same way across 

all fl ight phases.

AI

FL

FL

AI

Servo 1

Servo 9

You can assure yourself that this works as stated 

by accessing the "Servo display" menu, which you 

can access from almost any menu level by briefl y 

pressing the  keys on the left touch pad at the 

same time (see page 230):

• "AILE" column

When braking the model as it comes in to land, 

neither of the two aileron fl aps should ever be 

defl ected more than half of the possible travel 

upwards, to ensure that enough travel is available to 

control the model along its longitudinal axis (aileron 

function).

AI

FL

FL2

FL2

FL

AI

• "FLAP" (and "FLAP2") column

As the model is braked on the landing approach, 

both pairs of fl aps can be set to defl ect by different 

amounts, e. g.:

AI

FL

FL2

FL2

FL

AI

AI

FL

FL2

FL2

FL

AI

• Combining AILE and FLAP for "Crow"
Detail program description - Control adjust 161

1

3

5

7

+

0%

0%

9

11

0%

0%

2

4

6

8

+

0%

0%

0%

10 0%

12

0%

0%

+100%

+100%

If this relatively simply variant should prove 

impossible for whichever reasons, then the 

alternative is a solution with two free mixers – and 

potentially involving the "MIX-only channel" menu 

(see page 193). 

In either case, however, the airbrake travels must 

then be fi ne-tuned on the "Servo adjustment" menu 

(see page 90).

 D.red. (Differential reduction)

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red

0%

0%

0% 0%

0% 0%

FLAP FLAP2

Earlier, we discussed the problems with the butterfl y 

(crow) confi guration. Namely: that with the use of aileron 

differential, the aileron effect can be strongly (negatively) 

affected by the aileron elevation. This is fi rstly because 

further defl ection of the one aileron upwards is 

(almost) no longer possible and secondly because the 

downward-defl ected aileron – depending on the elevation 

and degree of differential confi gured – is often unable to 

achieve even its "normal" position.

To be able to restore the effect of the aileron altered 

in this way as far as possible, you should ensure that 

you make use of the automated "Differential reduction" 

feature. This feature continuously reduces the degree of 

aileron differential as the airbrake system is extended. 

The feature is confi gurable and can even be set to 

suppress differential entirely. 

A value of 0% means that the "aileron differential" set 

at the transmitter remains fully in force. An entry that 

equals the % value set for aileron differential means the 

differential is fully eliminated once the butterfl y function 

is at maximum travel, i. e. with fl aps fully extended. 

Setting a reduction value greater than the aileron 

differential confi gured will eliminate the latter even 

before the full travel of the airbrake joystick.

Values can be set in the range 0 to150%.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

 Elevat curve (Brake  elevator)

Elevat curve

BRAKE SETTINGS

Crow

D.red

0%

0%

0% 0%

0% 0%

If the airbrake control – to be set to 1, 7, 8 or 9 on the 

"Brake Off" line of the "Model type" menu (page 83) – is 

used to extend the fl aps as described previously for the 

"Brake settings" menu, this will often have a negative 

effect on the aircraft model's airspeed. This mixer can 

be used to compensate this type of effect by applying a 

corrective value to the elevator. 

By briefl y tapping the center SET key on the right touch 

pad, you can switch to the display screen as shown below:

Input

Output

Point ?

–100%

0%

0%

Brake

normal

Ele

Curve off

Normal

Confi guration notes for "Elevat curve" (brake  EL)

The offset that you have confi gured on the "Model type" 

menu (page 82) affects this mixer:

The vertical line on the display that indicates the 

position of the airbrake control only moves from 

the edge of the graph when the confi gured offset is 

exceeded. Simultaneously, the airbrake control travel is 

automatically expanded back to 100%, as described for 

the "Model type" menu.

Accordingly, the mixer's neutral point always lies on the 

left edge, independently of the offset confi gured. 

Now adjust the elevator curve in the direction of the 

opposite end-point in accordance with the requirements. 

Note that the approach taken to confi guring this 5-point 

curve mixer follows the same principles as already 

described (within the scope of the "Channel 1 curve" 

menu, page 116) as applicable to the curve mixers, i. e.:

Input

Output

Point 1

–19%

–6%

–7%

Brake

Normal

EL

Curve on
162 Detail program description - Control adjust

In each case, you should test the setting selected at 

the appropriate altitude and re-adjust as required. As 

you do, however, ensure that your model does not slow 

down excessively with the braking system extended! 

Otherwise, you run the risk that, after the braking 

system is retracted, e. g. to extend a landing approach 

that was too short, for example, your model pancakes or 

even stalls.

 Aileron differential

(Only for "2AIL 1FL". If "2AIL 2/4 FL" is selected, 

included on the multi-fl ap menu, see page 157.)

Aile.diff

Brake settings

0%

AI 0%

WING MIXERS

RU –––

Multi-flap menu

Normal

On this line you can set the aileron differential for the 

two aileron servos.

If you are unsure about the meaning of differential 

travel, please read the appropriate explanation at the 

start of this section on page 148.

The adjustment range of -100% to +100% makes 

it possible to set the correct direction of differential 

regardless of the direction of rotation of the aileron and 

fl ap servos.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

 Aileron  rudder

Brake settings

AI 0%

WING MIXERS

FL EL 0% 0%

–––

–––

RU

Multi-flap menu

Normal

Here, you can set the degree to which the rudder follows 

commands acting on ailerons. This is used in particular 

in connection with aileron differential to suppress 

adverse yaw and thus make it easier to fl y "clean" 

curves. You can of course still issue separate commands 

to the rudder. 

The mixer direction is typically chosen to ensure that 

the rudder moves in the direction of the aileron that is 

defl ected upwards.

Settings are always made symmetrically relative to the 

neutral point of the aileron joystick.

The adjustment range of ± 150% lets you set the 

direction of defl ection as appropriate. Optionally, this 

mixer can be activated and deactivated by using one of 

the switches that do not reset themselves (SW 2 ... 8) or 

a control switch. This means you can then also control 

the model using only the ailerons or rudder, as required. 

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

A value of around 50% is generally an excellent starting 

point.

 Flap  elevator

Brake settings

AI 0%

WING MIXERS

FL EL 0% 0%

–––

–––

RU

Multi-flap menu

Normal

When setting camber-changing fl aps, one side-effect 

can be to generate moments causing movement around 

the transverse axis. Equally, however, it may also be 

desirable that e. g. your aircraft model opts for a more 

pacey fl ight style with the fl aps slightly raised. This mixer 

can be used to achieve both results.

With this mixer, the extension of the fl aps – depending on 

the value confi gured – automatically ensures the elevator 

position follows suit. Symmetrical or asymmetrical 

settings relative to the neutral point of the fl ap control 

are possible.

If required, the mixer can be switched on or off by 

assigning a switch in the right column.

Values can be set in the range ±150%. The "typical" 

values confi gured for this mixer are single-digit or low 

two-digit values.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

Note:

If you have used the "Control adjust" menu to assign a 

transmitter control or switch, as described under ▲" on 

page 159, then the latter will also affect this mixer.
Detail program description - Control adjust 163
164 Detail program description - Control adjust

 Helicopter mixers

Flight phase-specifi c setting of collective pitch, throttle and tail rotor

On this menu ...

Free mixers

MIX active/phase

Fl. phase timers

Helicopter mixer

MIX-only channel

Dual mixer

... all of the fl ight phase-specifi c helicopter mixers are 

described, with the exception of the mixers for autorotation fl ight (discussed from page 178 onwards.) 

These mixers are used for the basic set-up of a model 

helicopter.

For fl ight phase programming, see the menus:

• "Base setup model", page 74

• "Phase settings", page 132

• "Phase assignment", page 134

When you actuate a switch for a specifi c fl ight phase, 

then the associated fl ight phase, e. g. "Normal", is 

displayed at the lower left edge of the display screen:

C1

C1

Pitch

Throttle

Tail

Tail 0%

Roll 0%

Throttle

Roll

Throttle

Tail

Nick

Nick

Throttle

Tail

Swash rotation

Swash limiter

0%

0%

0%

0°

OFF

Normal

Gyro suppress 0%

In each of these fl ight phases – with the exception of 

the auto-rotation phase – the typical helicopter mixing 

and coupling functions shown in the screen-shot 

above are available for setting up the model helicopter. 

These functions are described in the fi rst part of this 

comprehensive chapter.

General information on mixers, 

(see also pages 145 and 180)

An arrow "" indicates a mixer. A mixer "branches off" 

the signal fl ow of a control function at a particular point, 

in order to use this fl ow to cause a predetermined effect 

on a further control channel and, ultimately, the receiver 

output. The "Nick  Tail" mixer, for example, means 

that the tail rotor servo will be confi gured to follow 

commands from the pitch-axis joystick.

Basic programming procedure:

1. Select the mixer by using the arrow keys on the left 

or right touch pad.

Depending on the mixer, the lower line of the display 

will show SEL or the " " icon, which indicates that 

you need to move to a second page.

2. The linear mixer ratios can be set directly by briefl y 

tapping the center SET key on the right touch pad: 

Use the arrow keys to confi gure the mixer ratio.

Otherwise you will need to switch to the second 

screen page where you can set up the appropriate 

curve mixer.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

3. Complete the confi guration by tapping the center 

SET key on the right touch pad again.

4. You can page back by tapping the center ESC key on 

the left touch pad.

Description of helicopter mixers

To confi gure collective pitch curve settings and the two 

mixers "Channel 1  Throttle" and "Channel 1  Tail 

rotor", curve mixers are available in all fl ight phases. 

Accordingly, these mixers also permit the programming 

of non-linear mixing ratios along the path of joystick 

travel, if required. Switch to the display screen for curve 

settings by briefl y tapping the center SET key on the 

right touch pad – see discussion below.

The curve is set up basically in the same way as the 

Channel 1 curve for helicopters, but we will describe 

it again here in detail using pitch confi guration as an 

example, to save you having to leaf through the manual.

In the remaining lines, fi rst activate the value fi eld and 

then use the arrow keys on the left or right touch pad to 

set a mixer value in the value fi eld (now highlighted).

The settings available are rounded off with the "swash 

limiter" option: These option can be confi gured to 

limit the maximum defl ection of the swashplate servo. 

Together, these settings confi gure the basic set-up of 

the helicopter model. 

In the "Autorotation" fl ight phase as described on page 

178, however, the mixers "C1  Throttle" and "C1 

 Tail" are not needed and therefore switched to a 

confi gurable default value.

If you want to reset any changed parameters to 

their default values, you can do so at any time by 

simultaneously tapping the  or  keys on the 

right touch pad (CLEAR).

 Collective pitch (Collective pitch curve (C1  Pitch))

If necessary, use the arrow keys  on the left or right 

touch pad to move to the "Pitch" line. Now briefl y tap the 

center SET key on the right touch pad:
Detail program description - Control adjust 165

Input

Output

Point ?

0%

0%

0%

Pitch

Normal

Curve off

Unlike the "Channel 1 curve" menu, however, this 

display relates only to the control curve of the pitch 

servos: the "Channel 1 curve", on the other hand, affects 

all servos controlled via the throttle/collective pitch stick.

Note that the output signal of the "Channel 1 curve" 

option thus functions as an input signal for the 

collective pitch curve programmed here: In the 

graph, the vertical line is synchronized with the 

throttle/collective pitch stick and therefore follows 

the current Channel 1 curve characteristic.

The control curve can be defi ned (separately per fl ight 

phase) by up to 6 points, termed "reference points", 

placed at any point along the joystick travel.

Initially, however, fewer reference points are adequate 

for setting up the collective pitch curve. We recommend 

beginning with three reference points to start with. These 

three points – namely the two end-points "Pitch low (L)" 

(= -100% control travel) and "Pitch high (H)" (= +100% 

control travel) plus a point at the center of control travel 

still to be set – defi ne an initial linear profi le for the 

collective pitch curve.

Programming details

First, switch to your chosen fl ight phase, e. g. "Normal".

The throttle/collective pitch stick is used to move the 

vertical line in the graph between the two end-points 

"Point L" (minimum pitch at -100%) and "Point H" 

(maximum pitch at +100% control travel): at the same 

time, the current joystick position is shown numerically 

on the "Input" line (-100% to +100%). 

The point at which the vertical line crosses the curve is 

termed the "Output", and can be varied at the maximum 

of 6 reference points within the range -125% to +125%. 

A control signal modifi ed in this way affects only the 

collective pitch servos. 

In the example to the left, the joystick is at exactly 0% of 

control travel and also generates an output signal of 0%, 

since the characteristic curve is linear.

Up to 4 additional reference points can be set between 

the two end-points "L" and "H", although the distance 

between neighboring reference points must not be less 

than approx. 25%.

Setting reference points

If necessary, use the left or right arrow key  to drag 

the marker frame downwards, until it is at the "Point" 

line:

?

0%

0%

0%

Pitch

Input

Output

Point

Normal

Curve off

Move the joystick. If the display shows a framed 

question mark, then you can set the next reference point 

by tapping the center SET key on the right touch pad. 

Simultaneously, the "?" is replaced by its number and 

the value fi eld to the right of the reference point number 

is highlighted:

1

0%

0%

Pitch

0%

Input

Output

Point

Normal

Curve off

The order in which you generate the (maximum) 4 

reference points between the end-points "L" and "H" is 

irrelevant, since the reference points are continuously 

renumbered automatically from left to right as they are 

entered.

Confi guring reference points

To confi gure a point, use the joystick to move the vertical 

line onto the point you wish to change. The number 

and current curve value of this point are displayed on 

the left side of the display, on the "Point" line. Briefl y 

tap the center SET key on the right touch pad. Use the 

arrow keys on the right touch pad to change the current 

curve value shown in the highlighted fi eld. The possible 

range is -125% to +125% and changes do not affect 

neighboring reference points. 

+75%

+75%

Input

Output

Point 1

0%

Pitch

Normal

Curve off

In this sample screen image, reference point "1" has 

been set to +75%. 

If you wish, however, other points can also be set. At 

-50%, for example ...
166 Detail program description - Control adjust

–50%

–12%

Input

Output

Point 1

Pitch

Normal

Curve off

–12%

... and/or a further point at +50%:

+50%

+88%

3

Pitch

+88%

Input

Output

Point

Normal

Curve off

To do so, use the joystick to move to the corresponding 

area. As soon as a "?" appears in the frame on the 

"Point" line, the respective point can be set by pressing 

the arrow keys on the right touch pad. Just as with other 

points, this can be confi gured ... 

+50%

–50%

3 –50%

Pitch

Input

Output

Point

Normal

Curve off

... or, by tapping the arrow keys  or  on the 

right touch pad at the same time (CLEAR), can be 

deleted once again. 

The "L" and "H" points, on the other hand, CANNOT be 

deleted. 

Trim point function

Alternatively, assuming the value fi eld is active, i. e. 

highlighted, you can use the up or down arrow keys 

 on the left touch pad to jump to reference points 

already set. In this case, a triangle is shown on the 

graph to indicate each point jumped to. The arrow keys 

on the right touch pad can then be used to change the 

reference point jumped to as described above, entirely 

independently of the control position:

2

+50%

–75%

Pitch

–75%

Trim point

Input

Output

Point

Normal

Exit from trim point function setting by tapping the center 

ESC key on the left touch pad.

Trim offset function

Assuming the value fi eld is active, i. e. highlighted, you 

can not only use the up or down arrow keys  on the 

left touch pad to jump to reference points already set 

and change their values, but you can also use the 

keys on the left touch pad to vertically reposition an 

existing curve within the range ±25%:

1

0%

+50%

Pitch

+50%

Trim offset

Input

Output

Point

Normal

1

0%

0%

Pitch

0%

Trim offset

Input

Output

Point

Normal

You can also exit from this function by tapping the center 

ESC key on the left touch pad.

Trim x-axis function

This function is activated by tapping the left () or right 

() arrow key on the right touch pad with an active 

(i. e. highlighted) value fi eld. You can then use the arrow 

keys on the right touch pad to reposition the active point 

horizontally or vertically as you wish.

?

0%

–33%

Pitch

0%

Trim X-axis

Input

Output

Point

Normal

Notes:

• If you reposition the point horizontally further away 

from the current control position than approx. ±25%, 

a "?" sign re-appears in the line. This question mark 

does not refer to the repositioned point, however: 

instead, it signifi es that a further point can be set at 

the current control position.

• Please note that the percentage value on the 

"Output" line always relates to the current joystick 

position and not to the position of the point.
Detail program description - Control adjust 167

Deleting reference points

To delete one of the reference points (1 to max. 4), use 

the joystick to move the vertical line into the vicinity of 

the reference point in question. As soon as the reference 

point number and its associated value is shown on 

the "Point" line (see screen image above), you can 

activate the value fi eld on the "Point" line to highlight 

it by simultaneously tapping the  or  keys on 

the right touch pad (CLEAR) and then delete the value. 

Complete the operation by briefl y tapping the center key 

ESC on the left touch pad.

Smoothing the collective pitch curve

In the example below, sample reference points have 

been set ... 

Reference point 1 to +50%

Reference point 2 to +75%

Reference point 3 to -50%

... as described in the last section.

+50%

–50%

3 –50%

Pitch

Input

Output

Point

Normal

Curve off

This "jagged" curve profi le can be smoothed 

automatically simply by pressing a button. 

First – assuming a situation is confi gured as presented 

above – tap the center ESC button on the left touch pad 

to deactivate the value fi eld. Then use the arrow keys on 

the left or right touch pad to move the marker frame in 

an upwards direction to the "Curve" line. Now briefl y tap 

the center SET key on the right touch pad to activate the 

value fi eld on the "Curve" line:

+50%

–50%

3 –50%

Pitch

off

Input

Output

Point

Normal

Curve

Use the arrow keys on the right touch pad to set the 

value fi eld from "off" to "on" and complete this setup 

procedure by briefl y tapping the center SET key on the 

right touch pad or the center ESC key on the left touch 

pad:

+50%

–50%

3 –50%

Pitch

on

Input

Output

Point

Normal

Curve

Notes:

• If the joystick does not coincide with the exact 

reference point, please note that the percentage 

value on the "Output" line always relates to the 

current joystick position.

• As with the other screen images on these pages, the 

following screen shot shows a control curve created 

purely for the purposes of illustration. Please note, 

therefore, that the curve characteristics displayed 

do not in any way represent real-life collective pitch 

curves.

0%

–50%

2 –50%

Pitch

Input

Output

Point

Normal

Curve off

Sample collective pitch curves for various fl ight phases:

+100% +100% +100%

-100% -100% -100% Output Output Output

1 2 34 5 1 2 34 5 1 2 34 5

Control travel Control travel Control travel

Hover Aerobatics 3D

 C1  Throttle (Throttle curve)

0%

0%

0%

C1 Throttle

?

Input

Output

Point

Normal

Curve off

Unlike the "Channel 1 curve" menu, however, this 

display relates only to the control curve of the throttle 

servo: the "Channel 1 curve", on the other hand, affects 

all servos controlled via the throttle/collective pitch stick.

Note that the output signal of the "Channel 1 

curve" menu thus functions as an input signal for 

the throttle curve programmed here: In the graph, 

the vertical line is synchronized with the throttle/

collective pitch stick and therefore follows the 

current Channel 1 curve characteristic.

The throttle curve can also be defi ned (separately 
168 Detail program description - Control adjust

per fl ight phase) by up to 6 points, termed "reference 

points", placed at any point along the joystick travel.

The reference points are defi ned, adjusted and erased 

in the usual way, as explained in the previous section on 

the collective pitch curve. Start by defi ning the throttle 

curve with three points, namely the points "L" and "H" 

at the extremes, plus the Point "1" still to be set in the 

control center in order to match the motor power curve 

to the collective pitch curve.

Helicopter with carburetor or electric drive system 

with speed CONTROLLER

This setting relates only to the control curve of the 

throttle servo or the speed controller.

Setting the throttle curve to suit a helicopter equipped 

with a speed governor is discussed in the following 

section.

As with the confi guration of the collective pitch curve 

(see previous page), the throttle curve can also be 

defi ned by up to 6 points.

• In each case, set the control curve so that when the 

throttle/collective pitch stick is in its end position, 

the carburetor is fully open or the controller of an 

electrically-powered helicopter is set to maximum 

(except for auto-rotation fl ight, see page 178).

• For the hover point, which is normally at the control 

center, the carburetor setting or power control for the 

speed controller must be matched to the collective 

pitch curve so that the correct system rotational 

speed is obtained. 

• At the minimum position of the throttle/collective 

pitch stick, the throttle curve must fi rst be confi gured 

so that a glow motor runs at a speed considerably 

higher than idle speed and the clutch is fi rmly 

engaged.

The starting and stopping of the motor – whether 

glow or electric – always takes place using the 

throttle limiter (see below) within the respective 

fl ight phase.

This makes it unnecessary to program the two fl ight 

phases that may be familiar to you from using other 

remote control systems – namely "with idle-up" and 

"without idle-up", and with the associated "waste" of a 

fl ight phase for this purpose – since the mx-20 HoTT 

program offers a much more fl exible approach to fi netuning and optimizing increases to system rotational 

speed below the hover point than the "idle-up" approach 

taken by older mc radio control units.

Ensure that the throttle limiter is closed before you start 

the carburetor motor, i. e. so that the carburetor can 

be adjusted within the idle range only by using the idle 

trim. Ensure that you follow the safety instructions on 

page 177 at all times. If the throttle is set too high when 

switching on the transmitter, you will receive audible and 

visible warnings!

STARLET

#02

2:22h

Stop

Flug

K78

0:00

0:00

5.5V

5.2V99%

«Normal »

M

Throttle

too

high!

The following three graphs show (typical) 3-point throttle 

curves for various fl ight phases, such as hovering 

aerobatics and 3D fl ight.

Sample throttle curves for various fl ight phases:

+100% +100% +100%

-100% -100% -100% Output Output Output

1 2 34 5 1 2 34 5 1 2 34 5

Control travel Control travel Control travel

Hover Aerobatics 3D

Notes on using the "throttle limit" function:

• You should make use of the throttle limit function as 

a general rule (menu "Control adjust", page 104). 

This will fully isolate the throttle servo from the 

throttle curve with the throttle limit proportional rotary 
Detail program description - Control adjust 169

control turned fully to the left; the motor will be idling 

and respond only to C1 trim. This option permits you 

to start and also stop the motor from within any fl ight 

phase. 

Once the motor has started, turn the throttle limiter 

slowly in the direction of the opposite end-point, so 

you can once again activate the throttle servo fully 

using the throttle/collective pitch stick. To stop the 

throttle limiter limiting the throttle servo at its top endpoint, you should access the "Th.L.12" line on the 

"Control adjust" menu and set the control travel to 

+125% on the plus side of the "travel" column. Leave 

the default value of "GL" in the "Type" column alone, 

however, to confi gure this setting globally for all fl ight 

phases.

For a more fi nely-tuned control travel curve for the 

throttle limit control, you can also use the "Expo 

throttle limiter" (page 107). This gives you the option 

of defi ning the idle setting at the throttle limit control's 

center position, as readily determined both visually 

and audibly.

Set the throttle limiter to its center position and adjust 

the "EXPO thro lim." value as far as is needed until 

the motor is idling smoothly with the proportional 

rotary control set at its center point. In this position, 

the motor will then start without any problems. To 

switch off, you will turn the throttle limit control – thus 

without also using C1 switch-off trim – to its rearmost 

end-point. As you do, ensure that the affected servo 

cannot hit an end-stop mechanically.

The throttle restriction set by the throttle limiter is 

made visible as a horizontal bar in the diagram:

0%

0%

0%

C1 Throttle

?

Input

Output

Point

Normal

Curve off

The output signal for the throttle servo can never 

be higher than that set by the horizontal bar. In this 

example, it is thus max. ~50%.

• Since electric drive systems have no need for an 

idle setting, the basic confi guration of settings for 

an electrically-powered helicopter merely involves 

making sure that the control range of the throttle 

limiter is both higher and lower than the adjustment 

range of the speed controller (usually -100% to 

+100%) by a safe margin. If necessary, therefore, 

adjust the "travel" setting of the throttle limiter as 

appropriate on the "Th.L.12" line of the "Control 

adjust" menu. Leave the default value of "GL" in 

the "Type" column alone, however, to confi gure this 

setting globally for all fl ight phases. 

Fine-tuning of the throttle curve itself, however, must 

take place in fl ight – as with a glow-powered heli.

• If you wish to record the fl ight time of a (glowpowered) heli, you can assign a control switch to the 

throttle limit slider, and then use this to switch a timer 

on and off; see page 123.

For auto-rotation fl ight, an automatic switch-over 

is made from this mixer to a confi gurable default 

value; see page 178.

Helicopter with speed GOVERNOR

Unlike speed controllers, which merely adjust the 

output level – in a way similar to a carburetor – a 

speed governor keeps the speed of the system it is 

controlling constant by regulating the output provided 

autonomously. For glow-powered helis, the governor 

therefore controls the throttle servo itself as appropriate 

– or the speed controller of an electric heli in a 

comparable way. Accordingly, speed governors do not 

therefore require a traditional throttle curve but a speed 

setting. A deviation from the preset speed will therefore 

only take place if the level of output required exceeds 

the maximum level available.

Usually, receiver output 8 is reserved for connecting a 

speed governor; see the receiver assignments on page 

59. If this connection is in use, however, then the throttle 

limiter function is unavailable, since this exclusively 

affects the then unoccupied output 6, via the mixer 

"C1  Throttle". 

To still make use of the comfort- and safety-related 

features of the throttle limiter, you should ignore the 

general connection advice and connect the speed 

governor to receiver output 6. You then need only adjust 

the throttle curve appropriately, so this can take over the 

role of the "usual" transmitter control. 

Since in this case the "throttle curve" only regulates the 

target speed of the motor controller and this target motor 

speed should typically remain constant over the entire 

collective pitch adjustment range, the "C1 Throttle" 

mixer must be used to set a horizontal line – i.e. every 

(pitch) input value will result in the same ("throttle") 

output value – whose "height" is defi ned by the target 

motor speed. 

First, therefore, the reference points "1" to "4" – if 
170 Detail program description - Control adjust

 C1  Tail (Static torque compensation)

0%

0%

0%

C1 Tail

?

Input

Output

Point

Normal

Curve off

The default approach here is to preset a torque 

compensation curve with a linear mixer ratio of a uniform 

0%, as is required for a gyro sensor working in "heading 

lock mode" – see the screen image above. 

Important notice:

In this context, ensure that you comply with the 

instructions on adjusting your gyro: if not, you 

risk making adjustments that render your heli 

impossible to fl y.

If, on the other hand, you use your gyro sensor in the 

"normal" operating mode, or if it only has what is termed 

"normal mode", then confi gure the mixer as follows:

As with the confi guration of the collective pitch curve 

(see page 165), the control curve of the tail rotor can 

also be defi ned by up to 6 points. If required, therefore, 

you can modify the mixer at any time and preset both 

symmetrical and asymmetric mixer ratios both above 

and below the hover point. Before you do, however, 

ensure you have entered the correct direction of rotation 

for the main rotor on the "Helicopter type" menu.

present and set – are erased. Following this, the 

reference points "L" (input = -100%) and "H" (input 

= +100%) are then each set to the same value, for 

example:

–100%

+30%

+30%

C1 Throttle

L

Input

Output

Point

Normal

Curve off

The value to be set depends both on the speed 

governor used and on the target motor speed that is 

desired, and can, of course, be varied according to the 

fl ight phase.

For auto-rotation fl ight, an automatic switch-over 

is made from this mixer to a confi gurable default 

value; see page 178.

+100%

+30%

C1 Tail

H +30%

Input

Output

Point

Normal

Curve off

Starting with values of -30% for point "L" and +30% for 

point "H", the mixer is to be confi gured in such a way 

that the helicopter, even during prolonged vertically 

ascending or descending fl ights, does not deviate from 

the yaw axis as a result of the main rotor's altered 

torque while hovering. For hovering, trim should take 

place only via the (digital) tail rotor trim lever. 

For a reliable torque compensation setting, it is essential 

that the collective pitch and throttle curves have been 

set up correctly, i.e. that the rotor speed remains 

constant over the collective pitch's full adjustment range.

This third curve mixer applies only to the control curve 

of the tail rotor servo when the throttle/collective pitch 

stick is moved, whereas the "Channel 1 curve" (see 

page 119) acts on all servos that are affected by the 

throttle/collective pitch stick. Note that the output signal 

of the "Channel 1 curve" option also functions as an 

input signal for the tail rotor curve programmed here: 

In the graph, the vertical line is synchronized with the 

throttle/collective pitch stick and follows the current 

Channel 1 curve characteristic from the "Channel 1 

curve" menu.

In the auto-rotation fl ight phase this mixer is 

automatically switched off.
Detail program description - Control adjust 171

rotor defl ection. Set the mixer value so that there is no 

fall-off in system rotational speed.

 Roll  Throttle and Nick  Throttle

C1 Tail

Tail 0%

Roll 0%

Throttle

Throttle

SEL

Roll Tail

Nick Throttle

0%

0%

Normal

Increasing collective pitch is not the only change that 

requires the throttle to follow suit: major cyclic control 

movements also require this, i. e. if the swashplate is 

tilted in any direction. The mx-20 HoTT program lets 

you adjust the degree of throttle follow separately for roll 

and pitch-axis controls.

This offers particular advantages in aerobatic fl ying, e. g. 

when fl ying a roll: here, with moderate collective pitch 

values and the carburetor only about half-open, cyclic 

control travels are nonetheless executed that require 

much higher performance from the motor.

The mixer value can be varied within the range 0 to 

+100%. The correct mixer direction is automatically 

taken into account.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

In the auto-rotation fl ight phase this mixer is 

automatically switched off.

 Tail rotor  throttle

C1

C1

Pitch

Throttle

Tail

Tail 0%

Roll 0%

Throttle

Throttle

Normal SEL

While the tail rotor normally compensates for the effect 

of main rotor torque on the fuselage, it is also used to 

control the helicopter around the vertical axis. Increasing 

tail rotor thrust requires a corresponding adjustment 

to motor power, however, to avoid a fall-off in system 

rotational speed.

This mixer sets the extent to which the throttle follows 

the tail rotor. The throttle will follow on one side only, 

to the side on which the tail rotor thrust is increased. 

Values in the range 0% to +100% are therefore possible. 

The direction depends on the main rotor's direction of 

rotation (left or right), and this must fi rst be set correctly 

on the "Helicopter type" menu. For left-hand rotation 

systems, the throttle follows the tail rotor when the tail 

rotor joystick is moved to the left, and vice versa for 

right-hand rotation systems.

If you tap the  or  keys on the right touch 

pad (CLEAR) at the same time, this will reset values 

changed in the active (highlighted) fi eld back to 0%.

In the auto-rotation fl ight phase this mixer is 

automatically switched off.

Set-up notes:

To set the mixer value accurately you should either fi rst 

fl y several high-speed pirouettes against the direction of 

main rotor rotation or, if a strong wind is blowing, hover 

at right angles to the wind with a suffi ciently large tail 

 Roll  Tail and Nick  Tail

0%

Roll

0%

Throttle

SEL

Roll Tail

Nick Throttle

0%

0%

0%

Nick Tail

Gyro suppress

Normal

Increasing pitch is not the only change that requires a 

corresponding torque compensation via the tail rotor: 

major cyclic control movements also require this, e.g. 

if the swashplate is tilted in any direction. Here, too, 

the mx-20 HoTT program lets you confi gure settings 

for both types of tilt movement (roll and pitch-axis) 

separately.

For advanced aerobatics in particular, which involve 

very large control defl ections in the pitch-axis 

controls, e. g. the "Bo-turn" (vertical pull-up followed 

by tipping over around the pitch-axis) and tight loops, 

the uncompensated torque present in these fl ights 

causes the model to turn to a greater or lesser degree 

around the yaw axis. This spoils the appearance of the 

maneuver.

These two mixers permit static torque compensation to 

be activated by the swashplate tilting in any direction. 

The mixers work by always increasing tail rotor thrust, 

starting from the center point of the roll and pitch-axis 

sticks, i.e. they always generate a tail rotor defl ection 

in the same direction regardless of the direction of the 

command.

The mixer value can be varied within the range 0 to 

+100%.

The mixer direction is determined automatically by your 

defi nition of the direction of main rotor rotation on the 
172 Detail program description - Control adjust

"Helicopter type" menu, page 86.

In the auto-rotation fl ight phase this mixer is 

automatically switched off.

 Gyro suppression

0%

0%

SEL

Nick Throttle

0%

0°

Nick Tail

Swash rotation

Swash limiter OFF

Normal

Gyro suppress

Important: in normal situations, this function should 

not be used if your model is fi tted with a modern 

gyro system. In this context, ensure that you comply 

with the instructions on adjusting your gyro: if not, 

you risk making adjustments that render your heli 

impossible to fl y. This menu has nonetheless been 

retained in order to cater to a full range of requirements 

and fl ying habits.

With this option, the effect of the gyro sensor ("gyro") 

can be varied according to the tail rotor joystick position; 

this assumes the use of a gyro system whose gyro gain 

can be controlled from the transmitter via an auxiliary 

channel. This channel will be channel 7 for Graupner 

radio control systems. The gyro suppression function 

reduces gyro gain in a linear progression as the 

pilot increases the tail rotor defl ection. Without gyro 

suppression – i.e. when set to 0% – the gyro effect is 

constant, regardless of the joystick position.

With a transmitter control assigned on the "Gyro 7" line 

on the "Control adjust" menu (page 103), however, 

e. g. one of the CTRL 7 or 8 proportional rotary controls, 

the gyro gain can also be infi nitely varied (optionally 

according to the fl ight phase) between minimum and 

maximum gain. In this case, gyro gain is maximum at full 

defl ection of the slider, and zero at the opposite endpoint.

Of course, the software lets you limit the gyro gain range 

on both sides by altering the transmitter control travel.

Depending on the transmitter control position, the gyro 

gain at full travel on the tail rotor joystick is:

"current control position

minus

gyro suppression value".

Accordingly, if the transmitter control is at the neutral 

point, and gyro suppression is set to 100%, the gyro 

gain is reduced to zero as the tail rotor defl ection 

increases. For values between 100% and the maximum 

value of 199%, the gyro can be fully suppressed – 

depending on the transmitter control position – well 

before full defl ection of the tail rotor; see the diagram on 

the next page.

For the Graupner/JR gyro NEJ-120 BB, order no. 3277, 

both the upper and the lower values are set via rotary 

controls: control 1 sets the minimum gyro gain at the 

bottom position of the slider; control 2 sets the maximum

gain at the top end-point of the slider; the transition 

between these two values occurs roughly in the middle 

of the slider travel. 

In contrast, the PIEZO 900, PIEZO 2000 and PIEZO 

3000 gyro systems feature proportional, infi nitely 

variable adjustment of gyro gain; see below for typical 

diagrams.

As an example, the option to confi gure fl ight phasespecifi c – and static – gyro gain gives you the opportunity 

to exploit maximum stabilization for normal, slow fl ying, 

but to reduce gyro gain for fast circuits and aerobatics.

Samples of various gyro settings and confi guration 

notes

• Linear gyro suppression: 0% to 199%. 

With the tail rotor joystick in the center position, 

the resulting gyro effect is set using the selected 

transmitter control. Using a proportional rotary 

control, the effect is infi nitely variable between zero 

("min") and maximum ("max"), provided transmitter 

control travel is not restricted. With full tail rotor 

defl ection, the effective gyro gain is as follows:

"current control position 

minus 

gyro suppression value".

Accordingly: at 0% gyro suppression, gyro gain 

is constant for tail rotor joystick movement; at 

50% suppression, gyro gain is reduced to half if 

the assigned transmitter control is moved to the 

+50% position (as shown here); and only at >150% 

suppression is gain reduced to zero with the slider at 

this position, well before full tail rotor defl ection. 

Exemple:

+50 %

Í Gyro gain 

Î

left

Stick deflection tail rotor

centre right

Range of 

transmitter

control 7

• Linear gyro suppression with reduced control travel, 

e. g. -50% to +80% of full travel. 

Gyro gain is infi nitely variable within these transmitter 
Detail program description - Control adjust 173

control limits. Here too, for purposes of illustration, we 

plot gyro gain values in relation to tail rotor defl ection 

for various parameter values of gyro suppression.

Exemple:

+80 %

Í Gyro gain 

Î

left

Stick deflection tail rotor

centre right

Range of

transmitter

control 7

Adjusting the gyro sensor

To achieve the maximum possible level of stabilization 

for the helicopter with the gyro along the vertical axis, 

observe the following:

• The controls should have as little friction and "play" 

as possible.

• There should be no "spring" in the control linkage.

• Use a strong and – in particular – a fast servo 

When the gyro sensor detects a model rotation, the 

faster its response – a corresponding corrective change 

to tail rotor thrust – takes effect, the further the gyro 

gain adjustor can be moved without causing the tail of 

the model to start oscillating, and the better the model's 

stability about its vertical axis. If the response is slower, 

there is a risk that the model's tail will start to oscillate 

even at low gyro gain settings. Here, further reductions 

to gyro gain will need to be made to eliminate the 

oscillation.

If the model is fl ying forward at high speed or hovering 

in a powerful headwind, the net result of the stabilizing 

effect of the vertical fi n combined with the gyro may 

also lead to an overreaction that once again manifests 

itself through tail oscillation. To achieve optimum gyro 

stabilization under all conditions, you can make use of 

the option to adjust gyro gain from the transmitter using 

a transmitter control assigned to input "7", in connection 

with gyro suppression and/or the two settings on the 

Gyro NEJ-120 BB. 

Further notes on gyros with confi gurable multilevel gyro 

gain (e. g. NEJ-120 BB)

Since you cannot specify the gyro gain from the 

transmitter proportionally via the transmitter control, the 

gyro's own control 1 must be used to set the (weaker) 

gyro gain (e. g. for aerobatics) and control 2 the stronger 

gyro gain (e. g. for hovering ). Even though a proportional 

rotary control is used for control function 7, only a 

switch-over between these two values takes place and 

the setting is therefore not proportional. 

You should therefore advance control 2 to the point 

where the model is on the brink of oscillating when 

hovering in calm conditions, and advance control 1 to 

the point where the model does not oscillate with its 

tail even when fl ying at maximum speed into a strong 

headwind. Depending on the state of the weather 

and the fl ight program planned, you can also switch 

over the gyro gain from the transmitter – also with 

gyro suppression dependent on tail rotor defl ection if 

required. 

 Swashplate rotation

0%

0%

SEL

0%

0°

Nick Throttle

Nick Tail

Swash rotation

Swash limiter OFF

Normal

Gyro suppress

Some rotor head control systems make it necessary 

to incline the swashplate in a different direction from 

the intended inclination of the rotor plane when a cyclic 

control command is given. If your model features a 

four-bladed main rotor, for example, you may need to 

use this menu to set up a software-driven 45° rotation 

of the control linkage to the right, so that the pushrods 

from the swashplate to the rotor head can be set exactly 

vertical, ensuring that the blade control system works 

correctly, without unwanted differential effects. This 

eliminates the need to make mechanical changes to 

the control linkages. Negative angles equate to a virtual 

rotation of the rotor head to the left; positive angles a 

virtual rotation to the right.

 Swashplate limiting

0%

0%

SEL

0%

0°

Nick Throttle

Nick Tail

Swash rotation

Swash limiter OFF

Normal

Gyro suppress

This function works like a circular mechanical surround 

acting upon the stick which controls the swashplate, 

restricting the normally square stick travel to a circular 

range. In fact, if the helicopter is set up in such a way 
174 Detail program description - Control adjust

that the defl ections for roll and/or pitch-axis exploit the 

maximum travel mechanically possible, e. g. for 3D helis, 

then the total tilt applied to the swashplate if full roll 

and pitch-axis commands are applied simultaneously 

will be considerably greater (141% in numerical terms). 

The swashplate mechanism may then strike its endstops and in the worst case the ball-links could even be 

disengaged. 

The mx-20 HoTT transmitter contains a confi gurable 

software function for limiting the total swashplate travel, 

i.e. it restricts the tilt angle of the swashplate from 100% 

(the travel is limited to the value obtainable either with 

roll or pitch-axis alone) to 149% (no effective limit). In 

addition, the function can be set to "Off" and hence 

completely deactivated. The swash limiter can also be 

confi gured per model and per fl ight phase. 

This software solution is therefore much more fl exible 

than a physical circular surround attached to the stick 

unit: the latter can, in any case, only be used if the roll 

and pitch-axis functions are controlled by a common 

stick unit.

The sketch shown alongside 

illustrates the effect when set 

to 100%: the cross-hatched 

area of travel is curtailed and 

appears as a "dead zone".

If this function is used, "Dual 

Rate" should be set to 100% 

and Dual Rate values above 

100% should also not be 

used. If not, and you set a 

swashplate limit of 100%, for example, then swashplate 

movement will be restricted even if roll and pitch-axis 

commands are given separately. 

Adjustment range: 100 ... 149% and "Off".
Detail program description - Control adjust 175

 Fine-tuning the throttle and collective pitch curve

Practical approach

Although the throttle and collective pitch control systems 

are based on separate servos, they are always operated 

together by the throttle/collective pitch stick (except 

during auto-rotation fl ight). This coupling is performed by 

the helicopter program automatically. 

In the mx-20 HoTT program, the trim lever of control 

function 1 acts principally only on the throttle servo. 

However, in the "Stick mode" menu (see page 94) 

you can determine whether this should be used for idle 

trimming as part of the throttle limit function, or for idle 

trimming during the auto-rotation phase ("throttle AR").

The process of fi ne-tuning throttle and collective 

pitch, i. e. setting the motor power curve to match the 

collective blade pitch setting, is the most important 

aspect of setting up a model helicopter. The mx-20

HoTT software provides for independent confi guration 

of the throttle, collective pitch and torque compensation 

curves, in addition to the C1 control curve ("Channel 1 

curve" menu, page 119). 

While these curves can be modeled using up to 

six points, fewer points are generally suffi cient. We 

recommend starting with three-point curves to begin 

with. This involves setting individual values for the center 

point and other (optional) reference points, and for the 

two end-points ("L", "low", and "H", "high") of the throttle/

collective pitch stick: together, these defi ne the control 

curves. 

Before setting the throttle and collective pitch function, 

however, you should accurately calibrate the mechanical 

linkages for all the servos, following the set-up 

instructions for the helicopter in question.

Note:

The hover point should normally be set to the center 

position of the throttle / collective pitch stick. For 

some special cases, however, e. g. for "3D" fl ight, 

you may wish to program hover points that deviate 

from this standard. For example: one point for 

normal fl ight attitude above the center and one point 

for inverted fl ight attitude below the center.

 Idle setting and throttle curve

Note:

Since electric drive systems have no need for an idle 

setting, motor idling does not need to be calibrated. 

Fine-tuning of the throttle and collective pitch curve(s), 

however, must take place as for glow-powered helis.

The idle setting described in detail on pages 105 to 

107 always takes place with the throttle limiter closed – 

normally with the trim lever of the C1 function and only 

in special cases is the throttle limiter itself also utilized 

(as standard, the CTRL 6 proportional rotary control). 

The programming of a corresponding value for the "L" 

point of the throttle curve acts to set the descent speed 

of the motor, without infl uencing the hover confi guration.

Here, for example, you can use fl ight phase 

programming in order to confi gure a range of throttle 

curves. This increased system rotational speed 

below the hover point proves to be useful in certain 

circumstances, for example for fast, steep landing 

approaches with greatly reduced collective pitch, and for 

aerobatics. 

The screen image depicts a curve 

with a slightly changeable throttle 

setting below the hover point at 

the control center. Control travel OUTPUT

Different throttle curves are programmed for each fl ight 

phase, so that you can use the optimum set-up for both 

hovering and aerobatics:

• Low system rotational speed with smooth, gentle 

control response and low noise when hovering

• Higher rotor speed for aerobatics with motor power 

set close to the maximum. In this case, the throttle 

curve must also be adjusted in the hover range. 

 Basic set-up procedure

While the mx-20 HoTT transmitter permits the 

electronic confi guration of collective pitch curve and 

throttle curves to a large degree, fi rst ensure that you 

have correctly set all of the model's mechanical linkages 

as specifi ed by the helicopter manual. Experienced 

helicopter pilots will be glad to help you with this basic 

set-up.

The carburetor linkage must be set so that the throttle is 

just past the fully open setting with collective pitch set to 

maximum or, for electric helis, with the speed controller 

set to full. When the throttle limiter is closed, however, 

it must be possible to just close off the carburetor using 

the C1 trim lever (rapid throttle setting of the "digital 

trim", see page 54), without the servo mechanically 

striking its end-stop. For electric helis, it must be 

possible to cut the electric motor's speed controller 

safely with the throttle limiter closed.

Take great care when confi guring these settings, by 

adjusting the control linkage as required and/or altering 

the linkage point on the servo or carburetor lever. Only 

then should you optimize throttle servo fi ne-tuning 

electronically.

Caution:

Inform yourself thoroughly about the dangers and 
176 Detail program description - Control adjust

pitch setting for the hover and the maximum collective 

pitch setting (point "H") now provides you with a simple 

method of achieving constant system rotational speed 

from hovering right through to maximum climb.

First, perform a prolonged, vertical climb by moving 

the collective pitch stick to its end-point. Compared to 

the hover confi guration, motor speed should remain 

unchanged. 

If motor speed falls off in the climb, even with the drive 

system working at full power and therefore no further 

power increase is possible, then reduce maximum 

blade pitch angle at full defl ection of the collective 

pitch stick, i.e. the value of point "H". Conversely, you 

should increase the angle of attack if the motor speed 

increases during the climb. On the "Pitch" graph page, 

you should therefore use the collective pitch stick to 

move the vertical line to point "H" and change its value 

accordingly, using the arrow keys  on the right 

touch pad. 

This diagram shows only the 

changes when setting the 

maximum collective pitch value. 

+100%

-100%OUTPUT 1 2 34 5

Control travel

Hover

point

Then bring the model back to hover, which should, in 

turn, be achieved with the C1 stick at its center point. 

If the hover point is now achieved only by moving the 

collective pitch stick from the center point towards 

"higher" values, then you should compensate for this 

hover deviation by slightly increasing collective pitch for 

hover – i.e. for point "1" – until the model once again 

hovers with stick at its center. Conversely, if the model 

safety precautions applicable to handling motors 

and helicopters before starting the motor for the 

fi rst time!

With this basic set-up complete, the motor should 

be started in accordance with the motor operating 

instructions: idling can then be confi gured using the trim 

lever of the throttle/collective pitch stick. The idle position 

that you set is displayed on the transmitter's basic 

display by a horizontal bar alongside the display of the 

C1 trim lever position. Refer to the description of digital 

trim on page 54 of this manual.

The model should lift off the ground with the collective 

pitch stick roughly at its center point and hover roughly 

at the expected rotational speed. If this is not the case, 

proceed as follows:

1. The model does not lift off until the collective 

pitch stick is above the center point.

a) Rotational speed is too low

Remedy: On the graph 

page of the "C1 

throttle", increase the 

value for point "1".

+100%

-100%OUTPUT 1 2 34 5

Control travel

Hover

point

b) Rotational speed istoo 

high

 Remedy: Increase the 

blade angle of attack pitch 

by increasing the value 

of point "1" on the "Pitch" 

graph page.

+100%

-100%OUTPUT 1 2 34 5

Control travel

Hover

point

2. The model lifts off before the center point is 

reached.

a) Rotational speed is too 

high

 Remedy: Decrease the 

carburetor opening by 

reducing the value of point 

"1" on the graph page of 

the "C1  throttle".

+100%

-100%OUTPUT 1 2 34 5

Control travel

Hover

point

b) Rotational speed is too low

 Remedy: Decrease the 

blade angle of attack pitch 

by reducing the value of 

point "1" on the "Pitch" 

graph page.

+100%

-100%OUTPUT 1 2 34 5

Control travel

Hover

point

Important:

These settings must be reconfi gured until the model 

hovers at the correct rotational speed with the throttle/

collective pitch stick at its center point. The confi guration 

of all other model parameters depends on these settings 

being made correctly!

 Standard set-up

Standard set-up is completed on the basis of the basic 

set-up described above, whereby the model hovers 

in normal fl ight at the correct rotational speed with 

the throttle/collective pitch stick set to its center point: 

This means a set-up with which your model is capable 

of hovering and fl ying circuits in all phases while 

maintaining a constant rotational speed.

 Climb settings

The combination of throttle hover setting, collective 
Detail program description - Control adjust 177

blades spinning wildly.

Always make sure that nobody else

is standing near the helicopter 

where they could be injured.

In addition, you must never switch abruptly from idle 

to the fl ight setting by suddenly increasing system 

rotational speed. This will cause the rotor to accelerate 

very quickly, resulting in premature wear to the clutch 

and gear train. Since the main rotor blades are generally 

mounted on a freewheeling unit, they will be unable 

to keep pace with such rapid acceleration; they will 

respond by swinging far out of their normal position and 

may even cause a boom strike. 

After starting the motor, you should therefore use the 

throttle limiter to increase the system rotational speed 

slowly. If you have assigned a switch to the throttle 

limiter, always ensure that you use the "Control adjust" 

menu (page 100) to program a time constant of about 

5 seconds for running up the system rotational speed 

(opening the throttle limiter). Do not, however, program 

a delay for closing the throttle limiter. Leave the default 

value of "GL" in the "Type" column alone, however, to 

confi gure this setting globally for all fl ight phase

Once the model can fl y this maneuver properly, set the 

value for "Throttle min" – the value for point "L" on the 

graph page for "C1  throttle" – so that the rotational 

speed neither increases nor decreases. This completes 

the set-up procedure for throttle and collective pitch.

 Some important closing remarks

Before starting the motor, ensure that the throttle limiter 

is fully closed: this ensures that the carburetor now 

responds only to the C1 trim lever. If the carburetor is 

open too far when you switch on the transmitter, you will 

receive a visual and audible warning. Otherwise, if the 

carburetor or speed controller is open too far when the 

motor starts, there is a danger that the motor will run up 

to speed immediately after starting, and the centrifugal 

clutch will engage immediately.

Accordingly, you should

always hold the rotor 

head fi rmly when starting.

However, if you should accidentally start the motor with 

the carburetor too far open, the golden rule is this:

Don't panic!

Keep hold of the rotor head !

Don't let go! 

Instead, close the throttle limiter immediately, even if 

this risks damaging the drive system (in the worst case 

scenario). 

YOU are responsible for ensuring

that the helicopter never fl ies off

in an uncontrolled manner. 

The costs of repairing a clutch, a gearbox or even the 

motor itself are negligible, if you compare these to 

the injuries and damage that an uncontrolled model 

helicopter can cause if it is allowed to fl y around with its 

hovers below the mid-point, correct this by reducing the 

angle of attack appropriately.

You may also fi nd that it is necessary to correct the 

carburetor opening for the hover point (point "1") at "C1 

 throttle".

This diagram shows only the 

change to the hover point, i. e. 

collective pitch minimum and 

maximum are both left at -100% 

or +100%.

+100%

-100%OUTPUT 1 2 34 5

Control travel

Continue adjusting these settings until you really do 

achieve a constant rotational speed over the full control 

range between hover and climb.

 Descent setting

The descent setting should now be confi gured by 

placing the model in a steady descent from forward fl ight 

at a considerable altitude by fully reducing collective 

pitch; adjust the collective pitch minimum value (point 

"L") so that the model descends at an angle of 60° ... 

70°. On the "Pitch" graph page, you should therefore 

use the collective pitch stick to move the vertical line 

to point "L" and change its value accordingly, using the 

arrow keys on the right touch pad.

This diagram shows only the 

changes when setting the 

minimum collective pitch value. 

+100%

-100%OUTPUT 1 2 34 5

Control travel

Hover

point
178 Detail program description - Control adjust

Auto-rotation permits both full-size and model 

helicopters to land safely in a crisis, e. g. if the motor 

should fail. Moreover, if the tail rotor should fail, cutting 

the motor and landing using auto-rotation is also the 

only possible way to avoid a high-speed, uncontrollable 

rotation around the vertical axis and a resulting 

catastrophic crash. Accordingly, switchover TO the autorotation phase takes place immediately. 

When the switchover to the auto-rotation phase is made, 

the Helicopter mixer menu screen changes as follows:

Pitch

Thr setting AR

Tailoffset AR

Gyro suppress 0%

Swash rotation 0°

OFF

Autorot

–90%

0%

Swash limiter

During auto-rotation fl ight, the main rotor is no longer 

driven by the motor, but only by its own momentum 

and the the airfl ow through the rotor disc caused by the 

rapid descent. Since the energy stored by a rotor kept 

spinning in this way is rapidly consumed if the helicopter 

fl ares, pilots must not only have experience in handling 

helicopter models but must also consider carefully how 

the relevant functions should be confi gured.

The advanced pilot should therefore practice autorotation landings at regular intervals. Not only to be 

able to demonstrate mastery of the maneuver at 

competitions, but also to ensure the pilot can can land 

the helicopter undamaged from a great height if the 

motor should fail. For this purpose, the program provides 

a range of adjustment options designed to help the 

pilot fl y a motorized model in its unpowered state. Note 

 Helicopter mixers

 Auto-rotation settings

that the auto-rotation settings comprise a complete 

seventh fl ight phase, which provides access to all the 

fl ight phase- specifi c confi guration options, and to trims, 

collective pitch curve settings, etc., in particular. The 

following functions have special features not present in 

the powered fl ight phases:

Collective pitch (Collective pitch curve (C1  Pitch))

In powered fl ight, the maximum blade pitch angle 

is limited by available motor power. In auto-rotation, 

however, it is limited only by the point at which airfl ow 

ceases over the main rotor blades. Greater maximum 

collective pitch must therefore be set to ensure suffi cient 

thrust when fl aring the helicopter even as rotational 

speed is falling off. To do so, briefl y tap the center SET

key on the right touch pad to switch to the "Pitch" graph 

page and then use the joystick to move the vertical line 

to point "H". Start by setting a value that is about 10% 

to 20% larger than your "normal" maximum value for 

collective pitch. Initially, however, do NOT set a value 

that is considerably greater than for normal fl ight, since 

if you do so, the behavior of the collective pitch controls 

may then be very unfamiliar following the switchover. 

Indeed, there is a danger that the pilot will oversteer 

during the fl are and the model will balloon: this will case 

the rotor speed to collapse at a considerable altitude 

and the model will then crash to the ground. You can 

always re-adjust the value later after fl ying some test 

auto-rotations.

The minimum value for collective pitch can differ from 

that set for normal fl ight. This depends on the pilot's 

usual style for normal fl ight. For auto-rotation, however, 

you must always set a suffi ciently generous minimum 

value for collective pitch at point "L" to ensure your 

model can be brought out of forward fl ight at moderate 

speed into a descent at an angle of around 60–70° 

when collective pitch is reduced to a minimum. If, like 

most heli pilots, you have confi gured this kind of setting 

for normal fl ight anyway, then you can simply copy this 

value across.

If, however, you normally let your model "fall" at a 

shallower angle, then you should increase the value at 

point "L", and vice versa.

Approach angle for 

various wind conditions

Approach angle

in moderate 

wind

no wind

45°

60°

75°

in strong 

wind

As a rule, the collective pitch stick itself is not positioned 

right at the bottom of its travel for auto-rotation. Instead, 

it is typically between the hover position and the 

bottom end-point, offering the pilot the option of further 

adjusting pitch inclination using the pitch-axis controls. 

You can shorten the approach by pulling back on the 

pitch-axis stick and gently reducing collective pitch, or 

extend the approach by pushing forward on the pitchaxis stick and gently increasing collective pitch.

Throttle setting AR 

Although pilots will be expected to cut the glow motor 

completely during competitions, this is rather less 

advisable during training sessions, since you would then 

need to restart the motor following each practice autorotation landing.

During the training phase, you should therefore set the 
Detail program description - Control adjust 179

value on this line so that a glow motor is held at a safe 

idle during the auto-rotation phase without the clutch 

engaging; electric drive systems should be set safely to 

"Off". 

Note:

You may wish to make use of the "Motor Stop" option 

on the "Base setup model" menu as an alternative 

"Emergency STOP" function.

Tail rotor AR

In normal fl ight, the tail rotor is set so that it 

compensates for motor torque while the model is 

hovering. It therefore generates some a certain amount 

of thrust even in its normal position. The level of thrust is 

then varied by the tail rotor control system, and also by 

the various mixers which provide all manner of torque 

compensation, while the tail rotor trim is also used to 

compensate for varying weather conditions, fl uctuations 

in system rotational speed and other infl uences.

For auto-rotation, however, the main rotor is not driven 

by the motor, but by the "windmill" principle. Since this, 

in turn, does not generate any torque for which the tail 

rotor must compensate, all corresponding mixers are 

switched off automatically.

Since the absence of torque in auto-rotation also means 

the above-mentioned thrust is superfl uous, however, a 

different tail rotor confi guration is also required:

Cut the motor and place the helicopter on the ground in 

a level attitude. With the transmitter and receiving system 

switched on, select the fl ight phase "Auto-rotation" and 

then fold the tail rotor blades down. Now change the 

value on the "Tail rotor" line until the tail rotor blade angle 

of attack is zero degrees. Viewed from the tail, the tail 

rotor blades should be parallel to one another. 

Depending on the friction and running resistance of the 

gearbox, the fuselage may still yaw slightly, however. This 

relatively slight torque must then be corrected if necessary 

by adjusting the tail rotor blade pitch angle. This value 

will always be a fi gure between zero degrees and a pitch 

angle opposed to the pitch angle in normal fl ight.
180 Detail program description - Control adjust

 General notes on freely programmable mixers

The previous pages have described a wealth of readyto-use built-in coupling functions, in the context of the 

two menus "Wing mixers" and "Helicopter mixers". 

The fundamental signifi cance of mixers and the principle 

by which they work are described on page 145. The 

following section presents you with information relating 

to "free mixers". 

In addition to the pre-programmed mixers previously 

mentioned, the mx-20 HoTT offers a number of freely 

programmable mixers in every model memory, whose 

inputs, outputs and mixer ratios can be confi gured to suit 

your exact requirements: 

• 8 linear mixers, numbered M1 to M8

• 4 curve mixers, numbered K9 to K12

These 12 mixers are certainly adequate for most 

applications and are invariably suffi cient when you 

incorporate the pre-programmed coupling functions 

offered. On the "Mix active/phase" menu (see page 

192), you are also free to specify which of these 

12 mixers is activated or deactivated separately for each 

fl ight phase.

For the "free mixers", the signal present at any control 

function (1 to 12) can be assigned as the input signal. 

For the "switch channel" (see further below), the signal 

from any switch can be utilized. The signal that is 

present at the control channel and passed to the mixer 

input is always infl uenced by its own transmitter control 

and by any control characteristic that may have been 

set, e. g. those specifi ed by the "Dual Rate / Expo", 

"Channel 1 curve" and "Control adjust" menus. 

The mixer output acts on a control channel (1 to 12, 

depending on receiver type) that can also be assigned 

freely. Before this channel routes the signal to the servo, 

it can be infl uenced only by the "Servo adjustments" 

menu, i.e. by the the servo reverse, neutral point offset, 

servo travel and servo travel limit functions, and also 

possibly by " Tx. output swap ".

One control function can be used for any number of mix 

inputs simultaneously: if, for example, several mixers 

should be switched to act in parallel. 

Conversely, it is possible for any number of mixers to 

affect one and the same control channel. Particularly in 

the latter case, however, it is very important to ensure 

that the servo concerned does not strike its mechanical 

end-stops when several mixer signals accumulate 

to an excessive extent. For safety's sake it may be 

worth setting an appropriate travel limit on the "Servo 

adjustments" menu in such cases.

For more complex applications, mixers can be switched 

in sequence. In this case, it is not the (transmitter) signal 

at the "output" of a control function which forms the input 

signal of the "series-wired" mixer, but the (mixed) signal 

"further back" at the "input" of a control channel. The 

following description of the free mixers includes several 

examples of this type.

In the software, one "free mixer" is always initially 

activated. If you wish, however, the mixer can also be 

assigned an ON/OFF switch. Since there are so many 

functions to which switches can be assigned, you must 

be careful to avoid undesirable multiple assignments.

 The two key mixer parameters are: 

• ... the mixer ratio, which defi nes the extent to which 

the input signal acts on the output of the control 

channel connected to the mixer output. 

If you are using linear mixers, the mixer ratio can be 

set as symmetrical or asymmetric. Curve mixers can 

also be confi gured with up to 6 points to suit your 

application, enabling the implementation of highly 

non-linear curves.

• ... the neutral point of a mixer, which is also 

referred to as the "offset". 

The offset is the specifi c point along the travel of a 

transmitter control (joystick, CTRL 6 ... 8 proportional 

controls or switches 1 ... 9) at which the mixer no 

longer infl uences the control channel connected to 

its output. Normally, the neutral point is the center 

point of the transmitter control. However, the offset 

can also be set at any other point along the control 

travel. Since there are no restrictions on the design 

of the curve mixers, setting a mixer neutral point only 

makes sense for the 8 linear mixers.

 Switch channel "S" as a mixer input

Occasionally, however, only a constant control signal is 

required at the mixer input. A typical application would 

be a slightly increased "up-elevator" trim when the aerotow release is closed – fully independently of its normal 

trim setting. 

In this case a switch is assigned both to the aero-tow 

release and the mixer; it is then used not only to open 

and close the release, but also to pass the desired trim 

signal to the elevator via the mixer ratio. To identify this 

special arrangement, this mixer input control function in 

the program is designated "S" for "Switch channel". 

In addition, if the corresponding "target channel" should 

now no longer be infl uenced by its "normal" transmitter 

control, then you should isolate the latter from the 

function input of the affected control channel on the 

"MIX-only channel" menu (page 193). In the menu 

description that follows, an example is also given to 

illustrate this function.

Using the arrow keys on the left or right touch pad, page 
Detail program description - Control adjust 181

Basic programming procedure

1. Select the mixer you want by using the arrow keys 

 on the left or right touch pad.

2. Tap the center SET key on the right touch pad. The 

input fi eld on the line marked "fr" at the lower edge of 

the screen is now shown highlighted.

3. Use the arrow keys on the right touch pad to select 

the "fr" mixer input.

4. Tap the center SET key on the right touch pad; using 

the arrow key  on the left or right touch pad, switch 

to the column marked "to" on the lower edge of the 

screen and then tap the center SET key on the right 

touch pad once again. 

The input fi eld "to" is shown highlighted.

5. Use the arrow keys on the right touch pad to select 

the "to" mixer output.

6. Tap the center SET key on the right touch pad. 

Optionally, use the arrow key  on the left or right 

touch pad to switch to the column marked "ty" on 

the lower edge of the screen, in order to include 

the trim of the respective joystick in the mixer input 

signal ("Tr" for trim) and/or to add series switching for 

mixers ...

... and/or use the arrow key  on the left or right 

touch pad to switch to the column marked with the 

switch icon on the lower edge of the screen. 

Here, tap the center SET key on the right touch 

pad once again and assign a switch, following the 

description given in the section "Assigning transmitter 

controls, switches and control switches" (page 52).

7. Using the arrow key  on the left or right touch pad, 

switch to the column and then tap the center SET

key on the right touch pad. 

to the menu option ...

MIX active/phase

Fl. phase timers

Wing mixers

MIX-only channel

Dual mixer

Free mixers

MIX active/phase

Fl. phase timers

Helicopter mixer

MIX-only channel

Dual mixer

Free mixers

... on the multi-function list. Briefl y tap the center SET

key on the right touch pad to open this menu option.

 Free mixers

Freely-programmable linear and curve mixers

Regardless of the model type you have selected, each 

of the 24 model memory slots will offer you eight linear 

mixers (M1 ... M8) ...

Typ fr zu

M1

M2

M3

?? ??

?? ??

M4

M5

?? ??

?? ??

?? ??

... and 4 curve mixers (K9 ... K12), which also offer you 

the option of setting non-linear control characteristics:

Typ fr zu

M8

C9

C10

?? ??

?? ??

C11

C12

?? ??

?? ??

?? ??

In addition, the "MIX active/phase" menu (page 192) 

enables you to enable and disable particular mixers 

separately for specifi c fl ight phases. On the "Free 

mixers" menu, the blocked mixers are then 

suppressed in the corresponding fl ight phase. If 

you are hunting for a mixer that is not shown, you 

should therefore switch to the appropriate fl ight 

phase!

In this fi rst section, however, we will concentrate on how 

to program the fi rst screen page of the "free mixers". We 

will then move on to the method of programming mixer 

ratios, both for linear mixers and curve mixers, as found 

on the second screen page of this menu.
182 Detail program description - Control adjust

the previous page. 

After assigning a control function or the "S" switch 

channel in the "fr" column, the following is also displayed 

...

" to"

... on the lower edge of the screen. 

You use the input fi eld in this column to route the 

destination of the mixer, i. e. the mixer output, to one of 

the control channels. At the same time, additional fi elds 

also appear on the bottom line of the screen :

ty fr to

M1

M2

M3

6 EL

C1 EL

M4

M5

3 8

S EL

?? ??

Tr C4

4

2

In this example, four mixers have already been defi ned. 

The second mixer is already familiar to us in principle as 

"Elevat curve" from the "Brake settings" sub-menu on the 

"Wing mixers" menu, and the third is familiar from the 

"Tail" line ("2ELSv3+8") on the "Model type" menu. As a 

general rule, however, you should fi rst make use of the 

pre-programmed mixers. However, if you need asymmetric 

mixer ratios, want to go as far as programming non-linear 

curves or need to offset the mixer neutral point, then you 

should set or leave the pre-programmed mixers at "0%" 

and replace their use with free mixers.

 Erasing mixers

If you need to erase a previously-defi ned mixer, select 

the appropriate line with the arrow keys  on the 

left or right touch pad, switch to the "fr" column if you 

need to with the arrow keys and then briefl y tap the 

center SET button on the right touch pad:

ty fr to

M1

M2

M3

6 EL

C1 EL

M4

M5

 8

S EL

?? ??

Tr C4

4

2

3

The fi eld in the "fr" column for the mixer you want to 

delete will now be shown highlighted: tap both of the 

arrow keys  or  on the right touch pad at the 

same time (CLEAR):

Typ fr zu

M1

M2

M3

6 EL

C1 EL

M4

M5

??

S EL

?? ??

Tr C4

4

2

??

 Mixer switches

In the sample screen image shown above, switches "4" 

and "2" have been assigned to linear mixers 1 and 4 and 

to mixer 2 of the control switch "G4".

The switch symbol to the right of the switch number 

shows the current switch state.

Any mixers that have not been assigned any switch, 

as shown in the line on the bottom of the screen 

marked with a switch icon , are on by default!

A switch must be assigned to the fourth mixer if you wish 

to switch between two fi xed mixer values (still to be set) 

that correspond to the two end-points of a (proportional) 

transmitter control. Accordingly, the "switch channel" mixer 

cannot also be switched "on" or "off" as with the other 

mixers. 

8. Defi ne the mixer ratios on the second screen page.

9. Return to the fi rst page by using the center ESC key 

on the left touch pad.

" fr"

After selecting a mixer line and then tapping the center 

SET key on the right touch pad to highlight the value 

fi eld, use the arrow keys on the right touch pad to select 

one of the control functions: 1 ... 12 or S.

For the sake of legibility, control functions 1 ... 4 are 

marked as follows when setting wing mixers:

C1 Throttle/airbrake stick

AI Aileron stick

EL Elevator stick

RU Rudder stick

... and, for the heli program:

1 Throttle/collective pitch stick

2 Roll stick

3 Pitch-axis stick

4 Tail rotor stick

Note:

If you select control functions 5 ... 12 for fi xed-wing 

models or 5, 7 ... 12 for heli models, do not forget 

to assign a transmitter control in each case on the 

"Control adjust" menu!

"S" as switch channel

Selecting "S" (switch channel) in the "fr" column has 

the effect of passing a constant input signal to the mixer 

input, e. g. in order to add a little more "up-elevator" trim 

when the aero-tow release is closed, as mentioned on 
Detail program description - Control adjust 183

Trim Effect on mixer output

AR 

(throttle limit)

Linear, over full trim lever travel

GA

(throttle autorotation)

Only effective at minimum position of the 

assigned throttle limit control (CTRL 6 

proportional rotary control as standard)

 Switching mixers in series

As already explained on page 180, you can also 

switch mixers in series: Where mixers are switched 

in "sequence", the "input signal" of a control channel 

already on its way to the servo "branches off" and is 

directed to a further channel. In the "ty" column, select 

the right angle bracket " " – or "Tr ", if the trim should 

also act simultaneously on the mixer input:

ty fr to

M1

M2

M3

6 7

7 8

M4

M5 ?? ??

?? ??

?? ??

Example:

Two mixers (MIX 6  7 and 7  8):

a) WITHOUT series switching:

6 6

7

Servo 4,8 V C 577

Best.-Nr. 4101

Servo 4,8 V C 577

Best.-Nr. 4101

7

8

Servo 4,8 V C 577

Best.-Nr. 4101

MIX 1

MIX 2

If you intend to assign a control switch (G1 ... G4) as 

a switch, then please note that you must defi ne this 

appropriately BEFOREHAND on the "Control switch" 

menu. If you do not, you will assign an undefi ned control 

switch and therefore one that functions as a fi xed switch.

" Ty"

 Including the trim

For control functions 1 ... 4, you can also confi gure 

things so that the trim generated by the digital trim lever 

of the respective joystick affects the mixer input. In this 

case, briefl y tap the center SET key on the right touch 

pad and then use the arrow keys to select "Tr" in the 

highlighted fi eld: 

ty fr to

M1

M2

M3

6 EL

C1 EL

M4

M5

3 8

S EL

?? ??

C4

4

2

Tr

The effect of the C1 trim lever on the mixer output will 

depend on the function assigned to it on the "Model 

type" menu (page 82), in the "Motor on C1" column for 

fi xed-wing models ...

Trim Effect on mixer output

None Linear, over full trim lever travel

Forward Only effective if C1 stick is forward

Back Only effective if C1 stick is back

... or on the "Pitch" line of the "Stick mode" menu for 

helicopter models:

b) The same mixers WITH series switching:

6 6

7

Servo 4,8 V C 577

Best.-Nr. 4101

Servo 4,8 V C 577

Best.-Nr. 4101

7

8

Servo 4,8 V C 577

Best.-Nr. 4101

MIX 1

MIX 2

In this highly simplifi ed example, if mixer 2 is switched in 

series, then it does not "take over" solely the transmitter 

signal of control function 7 – as shown under a) – but, 

instead, the entire (mixed) signal present at the servo 

side of control channel 7, as shown under b). It then 

directs this in accordance with its confi gured mixer ratio 

forwards to control channel 8. In this case, the effect of 

transmitter control "6" extends as far as output "8". This 

kind of serial linkage can be extended as far as you 

wish. For example, another mixer "812" can be 

used to route the control signal from "6" as far as output 

"12", taking into consideration the associated mixer 

ratios. Of course, even with an active serial link, each 

separate mixer can still be controlled via the transmitter 

control assigned to the mixer input. Fixed-wing and 

helicopter mixers also work in the same way, when set 

up to switch "in sequence".

 Including phase trim

If you wish to apply the trim values of the FLAP channel 

("6") or the FLAP2 channel ("9") as stored on the 

"Phase trim" menu – and dependent on fl ight phase – 

then fi rst tap the center SET key on the right touch pad 

and use its arrow keys to select "P": 
184 Detail program description - Control adjust

* N.N. = Nomen Nominandum (the name to be stated)

ty fr to

M1

M2

M3

6 11

M4

M5 ?? ??

?? ??

?? ??

P

?? ??

Depending on the mixer value confi gured, a mixer can, 

as shown in the example above, route the signal from a 

fl ap control present (e.g.) on input 6 to control channel 

11, while also applying the FLAP trim value set on the 

"Phase trim" menu (page 136) for the respective fl ight 

phase.

 Other special features of free mixers

 Mixer input = mixer output

If you set up a mixer whose input is the same as its 

output, e.g. "C1  C1", you can achieve some very 

special effects in conjunction with the option of switching 

a free mixer on and off in any way you like. Typical 

examples for this feature can be found at the end of this 

section as example 2 on page 190, plus others in the 

section "Controlling timed sequences" on page 266.

Tip:

If you separate a control function, e.g. "9", from control 

channel 9" using the "MIX-only channel" menu (see 

page 193), then the servo response is defi ned only 

by the mixer ratio (yet to be specifi ed) of the mixer 

programmed on the same channel. This enables you 

to set up linear curves using mixers M1 ... 8 or 6-point 

control curves using curve mixers K9 ... 12 for any 

transmitter control, as described in the "Channel 1 

curve" menu, and also include them in fl ight phase 

switching if required. This method of "linking" is then 

not only also switchable, but can even be subject to a 

delay, by assigning an appropriate delay in the "– time 

+" column of the "Control adjust" menu. For more 

information, see the programming example entitled 

"Controlling timed sequences" on page 266.

 Mixer output affecting default software coupling of 

aileron, camber-changing fl ap or collective pitch 

servos

Before we start specifying the mixer ratio, we must 

fi rst give some thought to what happens if we permit a 

mixer to affect the default software coupling of aileron, 

camber-changing fl ap or collective pitch servos:

• Fixed-wing models:

Depending on the number of wing servos set on 

the "Aile/fl aps" line of the "Model type" menu, 

control channels are connected together via special 

mixers as follows: channels 2 and 5 for the "Aileron" 

function; channels 6 and 7 for the "Flap" function; and 

channels 9 and 10 for the FLAP2 servos (if present).

If mixer outputs are programmed to affect these kinds 

of couplings, then their effect on the respective fl ap 

pair derived from the "receiving" control channel must 

be accounted for:

Mixer Effect

N.N.*  2 The servo pair 2 + 5 responds with an 

aileron function

N.N.*  5 The servo pair 2 + 5 responds with a 

fl ap function

N.N.*  6 The servo pair 6 + 7 responds with a 

fl ap function

N.N.*  7 The servo pair 6 + 7 responds with an 

aileron function

N.N.*  9 The servo pair 9 + 10 responds with a 

fl ap function

N.N.*  10 The servo pair 9 + 10 responds with 

an aileron function

N.N.*  11 The servo pair 11 + 12 responds with 

a fl ap function

N.N.*  12 The servo pair 11 + 12 responds with 

an aileron function

• Model helicopters:

With heli mixers, collective pitch control may be 

provided by up to 4 servos connected to receiver 

outputs 1, 2, 3 and 5, depending on helicopter type. 

The software links these together to control collective 

pitch, roll and pitch-axis.

Elsewhere than the "Helicopter mixers" menu, 

it is not advisable to mix a free mixer into these 

channels, since some extremely complex interactions 

can result from such attempts. One of the few 

exceptions is "Collective pitch trim using a separate 

transmitter control" – see example 3 on page 190.

Important notices:

• With serial links in particular, remember that 

that the travels of the individual mixers are 

cumulative if multiple stick commands are made 

simultaneously: there is a risk that the servo(s) 

may strike a mechanical end-stop. If necessary, 

reduce "servo travel" to avoid this; alternatively, 

set "Travel limit" on the "Servo adjustments" 

menu and/or reduce mixer values.
Detail program description - Control adjust 185

• Use the option available to you at any time of 

switching to the "Servo display" menu (see 

page 230). This menu is reached from almost any 

menu option on the transmitter's basic display 

by briefl y tapping the keys on the left touch 

pad at the same time. This menu gives you the 

opportunity to check the effects of all of your 

settings on a single screen.

 Mixer ratios and mixer neutral point

Now that we have explained the wide-ranging nature of 

the mixer functions, the following section describes how 

to program linear and non-linear mixer curves. 

For each of the 12 available mixers, the mixer curves 

are programmed on a second page of the screen 

display. Use the arrow keys  on the left or right 

touch pad to select the desired mixer line. If necessary, 

use the touch pad's arrow keys to move to the right 

column ( ), and then briefl y tap the center SET key on 

the right touch pad in order to access the graph page.

 Mixers M1 ... 8: Setting linear mixer values

As a practical example, we will now defi ne a linear mixer 

curve to resolve the following problem:

For our motorized aircraft model, the two servos connected 

to receiver outputs 6 and 7 – defi ned on the "Aile/fl aps" 

line of the "Model type" menu as "... 2FL" – are to 

be deployed to activate landing fl aps. That is: when a 

transmitter control is moved, they must defl ect downwards 

only. This requires a simultaneous elevator trim, however.

First, use the "Control adjust" menu to assign a control 

such as the CTRL 6 proportional rotary control to input 

6. Comment: in this case, a transmitter control on input 

6 will control the two servos connected to receiver 

outputs 6 and 7 as fl aps, by default – as you can see by 

consulting the above table. Leave the default value of 

"GL" in the "Type" column alone, however, to confi gure 

this setting globally for all fl ight phases – as is the case 

for the free mixer.

"Control adjust" menu

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

GL

GL

GL

GL

typ

normal

Ct6

Note:

Note that if two fl ap servos have been selected, any 

transmitter control assigned to input 7 will be decoupled 

in the software in order to avoid errors in operating the 

fl aps. However, in the interests of safety, you should 

make a habit of leaving all inputs not currently required 

to "free", or of resetting these back to "free"!

Start by moving this transmitter control to its left endpoint and adjust the landing fl aps so that they are 

retracted or closed in this position. If you now move 

the dial to the right, the fl aps should move downwards; 

if not, you will need to adjust the direction of servo 

rotation.

We now turn our attention to the fi rst mixer shown in the 

screen image on page 182 ("6 EL"), to which switch 4 

was assigned:

ty fr to

M1

M2

M3

6 EL

C1 EL

M4

M5

S EL

?? ??

Tr C4

4

2

?? ??

Briefl y tap the center SET key on the right touch pad to 

open the second screen page: 

OFF

L.MIX 1 6 EL

If this screen appears, the mixer has not yet been 

activated using the assigned toggle switch – "4", in this 

example. If so, operate the switch:

L.MIX 1

0% 0%

0%

Offset

SYM ASY

6 EL

Mix input

The solid vertical line represents the current position of 

the transmitter control on input 6. (In the above diagram, 

located at the left edge, since the CTRL 7 transmitter 

control assigned to input 6 in this example (see previous 

page) is turned fully to the left.) The dotted vertical line 

in the middle of the diagram indicates the position of the 

mixer neutral point – see under "Offset", below. The solid 

horizontal line shows the mixer ratio, which currently has 
186 Detail program description - Control adjust

the value zero over the entire stick travel; accordingly, 

the elevator will not yet follow the movement of the fl aps.

First, the ...

 Offset (mixer neutral point)

... should be defi ned. To do so, use the arrow key 

on the left or right touch pad to move to the line under 

"Offset":

L.MIX 1

0% 0%

0%

Offset

STO SET

6 EL

Mix input

The dotted vertical line in the middle of the diagram 

indicates the position of the mixer neutral point 

("Offset"), i.e. the specifi c point along the control travel 

at which the mixer does NOT infl uence the control 

channel connected to its output. The default position for 

this point is at the control center.

However, since in our example the fl aps should be 

closed or retracted with the proportional rotary control 

turned fully to the left, and since the elevator should 

also not be further infl uenced in this position, we must 

relocate the mixer neutral point to precisely this point. To 

do so, turn the transmitter control used (in this example, 

CTRL 7) fully to the left if you have not already done 

so, and then briefl y tap the center SET key on the right 

touch pad. The dotted vertical line moves across to this 

point, the new mixer neutral point, which by defi nition 

always retains the "initial" value of zero. 

However, to illustrate our example better we now 

wish to set this "Offset" value to only -75%.

L.MIX 1

0% 0%

–75%

Offset

STO SET

6 EL

Mix input

Notes:

• By selecting SET with the arrow key  on the left or 

right touch pad and then tapping the center SET key 

on the right touch pad ...

L.MIX 1

0% 0%

Offset

STO SET

6 EL

Mix input

–75%

... you can then use the arrow keys on the left or 

right touch pad to set or readjust the offset value 

manually in increments of 1%.

• By selecting SET and then activating the value fi eld 

by tapping the center SET key on the right touch 

pad – – see screen image shown above – – you can 

then reset the mixer neutral point back to the control 

center automatically by simultaneously tapping the 

two arrow keys  or  on the right touch pad 

(CLEAR). 

 Symmetrical mixer ratios

The next task is to defi ne the mixer values above and 

below the mixer neutral point – – – starting from its current 

position. Move to the value fi eld on the line beneath the 

"Mix input" line, using the arrow key  on the left or right 

touch pad if necessary: If required, use the arrow keys 

 on the left or right touch pad to select the SYM fi eld, 

so as to confi gure the mixer value symmetrically with the 

offset point just set. After briefl y tapping the center SET

key on the right touch pad, you can then use the arrow 

keys on the right touch pad to set a value from -150% to 

+150% in the two highlighted fi elds. Note that the mixer 

value set always refers to the input signal of the respective 

transmitter control (control signal)! Negative mixer values 

reverse the direction of the mixer.

Simultaneously tapping the two arrow keys  or 

on the right touch pad (CLEAR) will erase the mixer 

ratio in the highlighted fi eld.

The "optimum" value in our example will certainly need 

fl ight-testing.

L.MIX 1

–75%

Offset

SYM ASY

6 EL

Mix input

+20% +20%

Earlier, we set the mixer neutral point at -75% of control 

travel: as a result, the elevator ("EL") will exhibit a 

(slight) down-elevator effect even at the neutral point 

of the landing fl aps and this is naturally undesirable. 

Accordingly, you should reposition the mixer neutral 

point to -100% of control travel, as described earlier.
Detail program description - Control adjust 187

L.MIX 1

+20% +20%

–100%

Offset

STO SET

6 EL

Mix input

If you were now to reset the offset currently set at -100% 

back as far as 0% of control travel – by selecting the 

SET fi eld with the arrow keyon the left or right 

touch pad, activating the value fi eld and then tapping 

the two arrow keys  or  on the right touch pad 

(CLEAR), then you will receive the following screen:

L.MIX 1

+20% +20%

0%

Offset

STO

6 EL

Mix input

SET

 Asymmetric mixer ratios

In many cases, however, we require different mixer 

values on each side of the mixer neutral point. 

First, reset the offset of the mixer used in the example 

"6  EL" to 0%, if required (see screen image above). 

Using the arrow key  on the left or right touch pad, 

select the ASY fi eld and then tap the center SET key 

on the right touch pad. If you now move the proportional 

rotary control assigned to input 6 – in this example, 

CTRL 7 – in each of the corresponding directions, 

you can use the arrow keys on the right touch pad to 

confi gure the mixer ratios for each of the two control 

directions, i.e. left and right of the confi gured offset point:

* N.N. = Nomen Nominandum (the name to be stated)

L.MIX 1

0%

Offset

SYM ASY

6 EL

Mix input

+55% +20%

Note:

If you are using a switch channel mixer of the "S  N.N.*" 

type, then you need to actuate the assigned switch. The 

vertical then jumps between the left and right side.

 Setting the curve mixers K9 ... K12

These four curve mixers enable you to defi ne extremely 

non-linear mixer curves by placing up to 4 freely 

positionable points between the two endpoints "L" (low 

= -100% control travel) and "H" (high = +100% control 

travel) along the control travel.

If you have already read the description of the "Channel 

1 curve" menu, or the method of programming 6-point 

curves on the"Helicopter mixers" menu, you can 

safely skip the following description.

Programming details

The control curve is defi ned by up to 6 points, known as 

"reference points". In the default software confi guration, 

2 reference points are already defi ned, namely only the 

two end-points, "L" and "H"; see the next screen image.

The following section applies to "any" mixer to which we 

wish to assign a non-linear curve characteristic.

The examples shown in the following section 

are merely illustrative, however, and they do not 

represent real-life mixer curves.

–45%

0%

0%

Input

Output

Point ?

C.MIX 9

normal

Curve off

8 10

 Setting reference points

When you move the transmitter control assigned to the 

mixer input – here control function 8 – a vertical line 

in the graph follows the movement between the two 

end-points. The current control position is also shown 

numerically on the "Input" line. The point at which this 

line intersects with the curve in question is named the 

"Output" and can be varied between -125% and +125% 

by setting reference points; see further below. This 

control signal acts on the mixer output.

In the above example, the transmitter control is on input 

8 at -45% of control travel. The output signal continue to 

show 0%, however, since no value has yet been entered.

Up to 4 additional reference points can be set between

the two end-points "L" and "H", although the distance 

between neighboring reference points must not be less 

than approx. 25%.

If necessary, use the left or right arrow keys on the left 

or right touch pad to drag the marker frame downwards, 

until it is on the "Point" line: 
188 Detail program description - Control adjust

–45%

0%

0%

Input

Output

Point ?

C.MIX 9

normal

Curve off

8 10

When you now briefl y tap the center SET key on the 

right touch pad, the "?" is replaced by a point number 

and the value fi eld to the right is activated:

–45%

0%

1

8 10

0%

Input

Output

Point

C.MIX 9

Curve off

Using the arrow keys on the right touch pad you can now 

change the point value within the range of ±125%, e. g.:

–45%

+50%

1

normal

8 10

+50%

Input

Output

Point

C.MIX 9

Curve off

Note:

If the joystick does not coincide with the exact reference 

point, please note that the percentage value on the 

"Output" line always relates to the current joystick position.

Continue in this way to set other reference points. Note 

that the order in which you generate the (maximum) 4 

reference points between the end-points "L" and "H" is 

irrelevant, since the reference points are continuously 

renumbered automatically from left to right as they are 

entered.

+35%

–55%

2

normal

8 10

–55%

Input

Output

Point

C.MIX 9

Curve off

 Erasing reference points

To erase one of the reference points between "L" and 

"H", use the transmitter control in question to move the 

vertical line onto or into the vicinity of the reference point 

in question. The reference point number and associated 

reference point value are shown on the "Point" line. The 

value fi eld is highlighted, see screen image above.

If necessary, use the arrow keys on the left or right touch 

pad to move the marker frame onto the "Pitch" line. Now 

briefl y tap the center SET key on the right touch pad. 

The value fi eld is shown highlighted. 

Now tap the two arrow keys  or  on the right 

touch pad at the same time (CLEAR).

The selected reference point is erased, and the 

numbering of the remaining reference points is updated 

as required. Briefl y tap the center ESC key on the left 

touch pad to complete the procedure.

Note that the reference points "L" and "H" cannot be erased.

 Changing reference point values

To change reference point values, use the associated 

transmitter control to move the vertical line onto the 

point you wish to change: "L", 1 ... 4 or "H". The number 

and current curve value of this point are displayed. After 

activating the value fi eld on the "Point" line by briefl y 

tapping the center SET key, use the arrow keys on the 

right touch pad to change the current curve value shown 

in the highlighted fi eld. The possible range is -125% to 

+125% and changes do not affect neighboring reference 

points. Briefl y tap the center ESC key on the left touch 

pad to complete the procedure.

 Trim point function

Alternatively, assuming the value fi eld is active, i. e. 

highlighted, you can use the up or down arrow keys 

 on the left touch pad to jump to reference points 

already set. In this case, a triangle is shown on the 

graph to indicate each point jumped to. The arrow keys 

on the right touch pad can then be used to change the 

reference point jumped to as described above, entirely 

independently of the control position:

+35%

–55%

2

normal

Kurve

8 10

–55%

Trim point

Input

Output

Point

C.MIX 9

Exit from trim point function setting by tapping the center 

ESC key on the left touch pad.

 Trim offset function

Assuming the value fi eld is active, i. e. highlighted, you 

can not only use the up or down arrow keys  on the 

left touch pad to jump to reference points already set 

and change their values, but you can also use the 

keys on the left touch pad to vertically reposition an 

existing curve within the range ±25%:
Detail program description - Control adjust 189

+35%

–30%

2

normal

Kurve

8 10

–30%

Trim offset

Input

Output

Point

C.MIX 9

+35%

–80%

2

normal

Kurve

8 10

–80%

Trim offset

Input

Output

Point

C.MIX 9

You can also exit from this function by tapping the center 

ESC key on the left touch pad.

 Trim x-axis function

This function is activated by tapping the left () or right 

() arrow key on the right touch pad with an active 

(i. e. highlighted) value fi eld. You can then use the arrow 

keys on the right touch pad to reposition the active point 

horizontally or vertically as you wish.

0%

–55%

?

normal

Kurve aus

8 10

–55%

Trim X-axis

Input

Output

Point

C.MIX 9

Notes:

• If you reposition the point horizontally further away 

from the current control position than approx. ±25%, 

a "?" sign re-appears in the line. This question mark 

does not refer to the repositioned point, however: 

instead, it signifi es that a further point can be set at 

the current control position.

• Please note that the percentage value on the 

"Output" line always relates to the current joystick 

position and not to the position of the point.

 Smoothing the curve

This "jagged" curve profi le can be smoothed 

automatically simply by pressing a button. 

Then use the arrow keys on the left or right touch pad 

to move the marker frame in an upwards direction to the 

"Curve" line, as required. Now briefl y tap the center SET

key on the right touch pad to activate the value fi eld on 

the "Curve" line:

0%

–12%

normal

8 10

0%

Input

Output

Point

C.MIX 9

Curve off

Use the arrow keys on the right touch pad to set the 

curve value from "off" to "on" and complete this setup 

procedure by briefl y tapping the center SET key on the 

right touch pad or the center ESC key on the left touch 

pad:

0%

–12%

?

normal

8 10

0%

Input

Output

Point

C.MIX 9

Curve on

Note:

The curves shown here are for demonstration purposes 

only and are not at all representative of real mixer 

curves. For real-world application examples, see the 

programming examples on pages 242 and 285.

 Examples:

1. To open and close an aero-tow, the switch SW 2 has 

already been assigned to control channel 8 on the 

"Control adjust" menu:

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

GL

GL

GL

GL

typ

normal

2

Subsequent aero-tow fl ying has proven that you 

always have to fl y with the up-elevator held slightly in 

during the tow. The solution will be to set up a mixer 

that applies slight up-elevator trim to the elevator 

servo connected to receiver output 3 when the aerotow release is closed. The screen-shot will be familiar 

from page 182: here, the fourth linear mixer has been 

set up for this function, with the switch channel "S" 

as mixer input: Move the selected switch to the OFF 

position and then switch ... 

ty fr to

M1

M2

M3

6 EL

C1 EL

M4

M5

3 8

S EL

?? ??

Tr C4

4

2
190 Detail program description - Control adjust

... to the mixer confi guration page. 

On this page, use the arrow key  on the left or 

right touch pad to select the line under "Offset" and 

then tap the center SET key on the right touch pad. 

Depending on the travel adjustment selected on the 

"Control adjust" menu and the switch position, the 

offset value jumps to +X% or -X%, e. g.:

L.MIX 4

0% 0%

+100%

Offset

STO SET

S EL

Mix input

Now use the arrow  key on the left or right touch 

pad to move to the line under "Mix input" and then 

tap the center SET key on the right touch pad. The 

value fi elds are now highlighted. After you have 

moved the selected switch to the mixer ON position, 

use the arrow keys on the right touch pad to set the 

required symmetrical mixer ratio. 

L.MIX 1

+100%

Offset

SYM ASY

6 EL

Mix input

+10% +10%

2. If you have a multi- fl ap wing featuring a "crow or 

butterfl y system" with (additional) airbrakes, and you 

wish to test the effect of this braking system with and 

without airbrakes, then you should simply set channel 

1 to "MIX-only" ...

MIX ONLY CHANNEL

only

normal

123 4 5 6

... and follow this by programming a free mixer "C1 

 C1", so as to restore your ability to control the 

airbrakes via servo 1. If you also assign a switch to 

this mixer, then you will be able to switch this mixer 

on and off as you please.

3. The fi nal example applies to model helicopters:

In the helicopter program, if you wish to assign 

collective pitch trim via one of the CTRL 6 ... 8 

proportional rotary controls, use the "Control 

adjust" menu to assign one of these transmitter 

controls to (e.g.) "Input 9". (Leave the default value 

of "GL" in the "Type" column alone, however, to 

confi gure this setting globally for all fl ight phases 

– as will be the case for the free mixer yet to be 

programmed. Finally, you then simply defi ne a free 

mixer "9  11" with a symmetrical mixer ratio of e. g. 

25%. Due to the internal coupling, this transmitter 

control then acts equally on all of the model's 

collective pitch servos without affecting the throttle 

servo. 

L.MIX 1

0%

Offset

SYM ASY

9 1

Mix input

+25% +25%

Decouple the assigned transmitter control from 

control channel 9 on the "MIX-only channel" menu, 

however, to ensure that any servo connected to 

receiver output 9 can no longer be operated by this 

transmitter control; see also page 193.
Detail program description - Control adjust 191
192 Detail program description - Control adjust

 MIX active/phase

Selecting mixers for fl ight phases

Using the arrow keys on the left or right touch pad, page 

to the menu option ...

Fl. phase timers

Wing mixers

MIX-only channel

Dual mixer

Free mixers

MIX active/phase

Helicopter mixer

Fl. phase timers

MIX-only channel

Dual mixer

Free mixers

MIX active/phase

... on the multi-function list. Briefl y tap the center SET

key on the right touch pad to open this menu option.

LinearM1

LinearM2

LinearM3

6 EL

C1 EL

LinearM4

3 8

S EL

yes

SEL

yes

yes

yes

MIX ACTIVE IN PHASE

normal

The "free mixers" on the previous menu can be enabled 

and disabled for specifi c fl ight phases. You therefore 

have complete freedom in assigning specifi c mixers only 

to specifi c fl ight phases.

Switch to your chosen fl ight phase and use the arrow 

keys to page through this menu. The mixers on the 

"Free mixers" menu are displayed in the center column.

Following the activation of the value fi eld by briefl y 

tapping the center SET key on the right touch pad, if the 

respective mixer is set to "--" by using the arrow keys on 

the left or right touch pad, then this mixer is deactivated 

in the fl ight phase shown at the bottom of the display 

and, simultaneously, removed from the list on the "Free 

mixers" menu:

LinearM1

LinearM2

LinearM3

6

LinearM4

3 8

S

Speed SEL

–––

EL

C1 EL

EL

yes

yes

yes

MIX ACTIVE IN PHASE

If you "lose" a mixer in this way from the "Free mixers" 

menu ...

ty fr to

M1

M3

6 EL

M4

M5

3 8

S EL

?? ??

4

2

M6 ?? ??

... then you should either switch through the fl ight 

phases until it appears again ... or, alternatively, switch 

to this menu and temporarily reactivate the mixer you 

are looking for:

ty fr to

M1

M2

M3

6 EL

C1 EL

M4

M5

3 8

S EL

?? ??

Tr C4

4

2
Detail program description - Control adjust 193

 MIX-only channel

Separating control functions from control channels for all fl ight phases

Using the arrow keys on the left or right touch pad, page 

to the menu option ...

Fl. phase timer

Wing mixers

Dual mixer

Free mixers

MIX active/phase

MIX-only channel

Fl. phase timer

Helicopter mixer

Dual mixer

Free mixers

MIX active/phase

MIX-only channel

... on the multi-function list. Briefl y tap the center SET

key on the right touch pad to open this menu option.

MIX ONLY CHANNEL

only

normal

123 4 5 6

On this menu, you can interrupt the normal signal fl ow 

between the control function on the input side and the 

control channel on the output side: the "traditional" 

transmitter control/servo connection no longer applies.

One particular use of the options offered by this fl ight 

phase-independent menu might to reliably keep one of 

the control channels "free" in all fl ight phases, as these 

control channels can be assigned a transmitter control 

or switch for specifi c fl ight phases on the " Control 

adjust " menu. 

Conversely, a joystick, transmitter control (CTRL 6 ... 

10) or switch (SW 1 ... 3, 8 and 9) "robbed" of its servo 

in this way can of course be used anywhere else as a 

transmitter control – even in a fl ight phase-specifi c way. 

See the programming examples to the right and on 

pages 255 and 266.

A joystick, transmitter control (CTRL 6 ... 10) or switch 

(SW 1 ... 3, 8 and 9) robbed of its servo by setting the 

channel to "MIX only" will then namely affect mixer 

inputs only ...

... and the servo connected to a channel set to "MIX 

only" is then also only accessible from the mixers 

programmed to its control channel, i.e. "(with) MIX(ers) 

only".

Accordingly, for any channel set to "MIX only", you can 

utilize both its control function and its control channel 

entirely independently of one another for any special 

functions you need; see the examples at the end of this 

section.

Use the arrow keys on the left or right touch pad to 

select the desired channel from 1 to 12 () and then 

briefl y tap the center SET key on the right touch pad, 

so as to switch as you please between "normal" ( ) and 

"only" mode ( ): 

normal

789 10 11 12

MIX ONLY CHANNEL

only

Examples:

• For model glider aircraft without airbrakes, the 

butterfl y function (page 160) is generally used as 

a landing aid. Just as with "normal" airbrakes, this 

is generally controlled using the C1 stick. While the 

(airbrakes) servo typically connected to channel 1 is 

then generally absent as a rule, receiver output 1 is 

still not "free", since the control signal of the brake 

stick is still present at this location.

Its control signal – – which in this example is not 

required – can be decoupled from control channel 

"1", and thus "free up" this channel from the C1 stick 

signal, by setting channel 1 to "MIX only" on the 

"MIX-only channel" menu. This makes it possible 

to use control channel "1", together with receiver 

connection "1", at any time for other purposes, via 

freely-programmable mixers – e. g. to connect up a 

speed controller.

• If your model has built-in airbrakes, however, and 

you would like to perhaps test the performance of a 

butterfl y system with and without airbrakes, simply 

set channel 1 to "MIX only" and program a free mixer 

"C1  C1", so as to restore your ability to control the 

airbrakes via servo 1. If you also assign a switch to 

this mixer, then you will be able to switch this mixer 

on and off as you please.
194 Detail program description - Control adjust

 Dual mixers

Same-sense/opposite-sense mixing of two control channels

Using the arrow keys on the left or right touch pad, page 

to the menu option ...

Fl. phase timers

Wing mixers

Free mixers

MIX active/phase

MIX-only channel

Dual mixer

Helicopter mixer

Fl. phase timers

Free mixers

MIX active/phase

MIX-only channel

Dual mixer

... on the multi-function list. Briefl y tap the center SET

key on the right touch pad to open this menu option.

Typ zu Diff.

DUAL MIXER

Mixer1

Mixer2

?? ??

Mixer3

Mixer4

?? ??

?? ??

?? ??

0%

0%

0%

0%

Similarly to a V-tail mixer, the four fl ight phaseindependent dual mixers couple ...

3 3

4

Servo 4,8 V C 577

Best.-Nr. 4101

Servo 4,8 V C 577

Best.-Nr. 4101

4

V-tail mixer

Control function inputs

Control channels

(receiver outputs)

Elevator stick

Rudder stick

Right rudder / elevato

Left rudder / elevator

Rudder

Elevator

Elevator

Rudder

Rudder

Elevator

... a same-sense " " and an opposite-sense "

" control function, although they permit any channel 

to be used and offer differential travel for the opposing 

function.

Note:

The symbols "  " and "  " indicate that the 

corresponding inputs act upon the two servos coupled 

by the mixer in the same and opposed directions 

respectively – they do not indicate the servos' direction 

of rotation! Accordingly, if wing fl aps are defl ected in 

the wrong direction, simply swap the two inputs around 

or use the servo reverse function from the "Servo 

adjustments" menu; see page 90.

In the software, the V-tail mixer already mentioned is 

supplemented by other "dual mixers" for the two aileron 

servos at receiver outputs 2 and 5 and for the fl ap pairs 

at outputs 6 and 7 (and 9 and 10 plus 11 and 12, if 

present). These are activated via the aileron stick and 

the transmitter control that has been assigned to input 

"6" on the "Control adjust" menu.

In the same way, the four freely-programmable dual 

mixers on this menu can be used to couple two further 

control functions, a feature that would otherwise only 

be possible with time-consuming programming of free 

mixers.

Here, we will use a "V-tail with rudder differential" as 

our example to explain the programming of a dual mixer 

(see also the example on page 255): 

Typ zu Diff.

Mixer1

Mixer2

EL

Mixer3

Mixer4

?? ??

?? ??

?? ??

0%

0%

0%

RU +25%

DUAL MIXER

Depending on activation, both servos operate either as 

elevators or rudders. Differential travel is effective only 

when a rudder command is given, in accordance with 

dual mixer assignment. In this case, both associated 

trim levers are effective. No additional free mixers are 

required for this arrangement. When using this mixer, 

however, the tail type MUST be entered as "normal" 

on the "Model type" menu. 

Example:

Model with two rudders, with differential travel and 

outward movement (e. g. swept-back fl ying wing):

Typ zu Diff.

Mixer1

Mixer2

 8

Mixer3

Mixer4

?? ??

?? ??

?? ??

0%

0%

0%

RU +75%

DUAL MIXER

When a rudder command is given, the second servo 

connected to output 8 follows suit. (With this type of 

programming, differential travel can be confi gured for 

the rudders.) In this case, too, trim from the rudder stick 
Detail program description - Control adjust 195

affects both servos. If the rudders are also required to 

defl ect outwards when the airbrakes are activated, then 

you should assign the C1 stick (transmitter control 1) to 

input 8 on the "Control adjust" menu. Finally, move to 

the "Offset" column and adjust the offset value until both 

rudders return to the neutral position. You may also need 

to "play" a little with the offset and travel adjustment 

settings.

Tip:

You can use the "Servoanzeige" menu to check 

all of the settings made in this way. This menu 

can be accessed from almost any other menu by 

simultaneously pressing the  keys on the left touch 

pad.
196 Detail program description - Control adjust

Using the arrow keys on the left or right touch pad, page 

to the menu option ...

Helicopter mixer

Free mixers

MIX active/phase

MIX-only channel

Dual mixer

Swaschplate mixer

... on the multi-function list. Briefl y tap the center SET

key on the right touch pad to open this menu option:

SWASH MIXER

Pitch

Roll

Nick

+61%

+61%

+61%

SEL

Note:

If "1 servo" is selected on the "Swashplate" line on the 

"Helicopter type" menu, this option is not shown on the 

multi-function list.

On the "Swashplate" line on the "Helicopter type"

menu, you have already defi ned the number of servos 

that are installed in your helicopter for collective pitch 

control; see page 86. This information is used to 

automatically couple together the functions for roll, 

pitch-axis and collective pitch, so that you do not need 

to defi ne any other mixers yourself.

If you have a model helicopter which only has a single 

collective pitch servo, this "Swashplate mixer" menu 

option is of course superfl uous, since the software 

will control the three swashplate servos for collective 

 Swashplate mixer

Collective pitch, roll, pitch-axis mixer

pitch, pitch-axis and roll independently of one other, 

i.e. without a mixer. In this scenario, this menu 

option is therefore no longer available to you from the 

multi-function list. With all other swashplate linkages 

employing 2 ... 4 collective pitch servos, the mixer ratios 

and directions are set up by default, as can be seen 

above. The preset is +61% in each case, but the value 

can be varied from -100% to +100% if required, by 

briefl y tapping the center SET key on the right touch pad 

and using the arrow keys. 

Simultaneously tapping the two arrow keys  or 

on the right touch pad (CLEAR) will reset the mixer ratio 

in the highlighted fi eld back to its default value of +61%. 

If the swashplate control system (collective pitch, 

roll and pitch-axis) does not respond to the joysticks 

properly, you should alter the mixer directions ("+" or "-") 

before trying to correct the directions of servo rotation.

Note:

Ensure that changed mixer values do not result in the 

servos mechanically striking their end-stops.

Using the arrow keys on the left or right touch pad, page 

to the menu option ...

Dual mixer

Teacher / pupil

Tx. output swap

Telemetry

Basic settings

Fail-safe adjust

Swashplate mixer

Teacher / pupil

Tx. output swap

Telemetry

Basic settings

Fail-safe adjust

... on the multi-function list. By briefl y pressing the central 

SET key of the right touch pad, this menu item opens:

FAIL SAFE

Pos

hold

123 4 5 6

 DELAY : 0.25s STO

The higher level of operating safety exhibited by the 

HoTT system when compared to traditional PPM 

technology results from the fact that the microprocessor 

built into the HoTT receiver not only exclusively 

processes the signals of "its" transmitter, but can 

also clean up "dirty" control signals that it receives. 

Only when these signals become too error-prone or 

garbled due to outside interference does the processor 

automatically replace the disrupted signals with the 

 Fail-safe
Detail program description - Control adjust 197

last received correct signal, temporarily stored in the 

receiver. This feature is confi gured by the settings as 

described below. This feature also suppresses brief 

interference caused by e. g. local drops in fi eld strength, 

which otherwise result in the familiar "glitches". In this 

case, the red LED lights up on the receiver.

If you have selected a PCM transmission mode for the 

active model memory but have not yet carried out the 

fail-safe programming, you will see a warning message 

on the screen when you switch on the transmitter:

Fail Safe

setup

t.b.d.

Programming procedure

The "Fail Safe" function determines the behavior of the 

receiver if communication between the transmitter and 

the receiver is disrupted. Receiver outputs 1 ... 12 can 

optionally ...

1. preserve the current position ("hold"):

if communication is disrupted, all servos programmed 

to "hold" mode remain at the positions judged to 

be the last valid positions by the receiver until the 

receiver picks up another valid control signal, or

2. move to a freely selectable position ("Pos") if 

interference should occur, following the expiry of the 

"time delay". 

Use the arrow keys  on the left or right touch pad 

to select the desired servo connection from 1 to 12 () 

and then briefl y tap the center SET key on the right touch 

pad, so as to switch as you please between the "hold" 

( ) and "Pos" mode ( ):

123 4 5 6

STO

FAIL SAFE

Pos

hold

 DELAY : 0.25s

Following this, use the arrow keys  on the left or 

right touch pad to select the "DELAY" option shown at 

the bottom of the display ... 

789 10 11 12

STO

FAIL SAFE

Pos

hold

 DELAY : 0.25s

... and then briefl y tap the center SET key on the right 

touch pad. Now use the touch pad's arrow keys to make 

your choice from the four possible time delays (0.25 s, 

0.5 s, 0.75 s and 1 s) offered.

Simultaneously tapping the arrow keys  or  on 

the right touch pad (CLEAR) ) will reset the highlighted 

fi eld back to its default value of 0.25 s.

Following this, use the arrow keys  on the left 

or right touch pad to select the STO fi eld at the 

bottom right of the screen. Then, use the associated 

transmitter controls to move the servos, which you have 

switched to position mode, into the desired positions 

SIMULTANEOUSLY.

Briefl y tap the center SET key on the right touch pad 

to store these positions as the fail-safe setting for the 

receiver, so that it can revert back to them if interference 

is experienced. 

Successful storage of the positions is confi rmed briefl y 

on the screen:

789 10 11 12

STO

Position

stored

FAIL SAFE

Pos

hold

 DELAY : 0.25s

Caution:

Ensure you make use of this safety net by at least 

programming the following for a fail-safe incident: 

for glow-powered models, set the motor throttle 

position to idle; for electric models, set the motor 

function to stop, or "Hold" for heli models. If 

interference should occur, the model is then less 

likely to fl y off on its own and cause damage to 

property or even personal injury. Consider asking an 

experienced pilot for advice.
198 Detail program description - Control adjust

 Teacher/pupil

 Connecting two transmitters for trainer mode with a trainer lead

Using the arrow keys on the left or right touch pad, page to 

the menu option "Teacher/pupil" on the multi-function list: 

Dual mixer

Tx. output swap

Telemetry

Basic settings

Fail-Safe adjust

Teacher / pupil

Swaschplate mixer

Tx. output swap

Telemetry

Basic settings

Fail-Safe adjust

Teacher / pupil

Briefl y tap the center SET key on the right touch pad to 

open this menu option:

TRAINER /Pupil

Pupil

Teach

2 3 4 5

SW: ––– BIND:

1

n/a

6

The screen image shown above shows the menu in its 

initial state: No transmitter controls have been released 

by the pupil ( ) and no switch is assigned ("SW: ---" 

bottom left in the screen image).

Teacher-pupil settings

Up to twelve control functions of the teacher transmitter 

"Teach" can be transferred to the pupil transmitter 

"Pupil", either individually or in any combination. 

The lower display line, named "Teach", therefore refers 

to the transmitter controls permanently connected 

to inputs 1 ... 4 (dual axis stick functions for fi xed-wing 

and heli model) and the CTRL 6 to 10 controls that are 

assigned or can be assigned to inputs 5 ... 12 (optionally 

fl ight phase-specifi c) on the "Control adjust" menu.

Note:

The assignment of transmitter controls on the "Control 

adjust" menu is possible only when the trainer mode 

connection is inactive.

Use the arrow keys  on the left or right touch pad 

to select the transmitter controls from 1 to 12 () to 

transfer to the pupil and then briefl y tap the center SET

key on the right touch pad in each case, so as to switch 

between "Teach" (Teacher)" ( ) and "Pupil" 

( ):

2 3 4 5

SW: ––– BIND:

1 6

TRAINER /Pupil

Pupil

Teach

n/a

To be able to carry out the transfer, you must then 

assign a trainer mode switch on the left of the display. 

To do so, use the arrow keys on the left or right touch 

pad to move the marker to the bottom left, to the right of 

"SW:" Here, assign a switch as described on page 52. 

Preferably, you should utilize one of the two momentary 

switches, SW 1 or SW 9, so as to be able to revert 

control back to the teacher transmitter at any time.

8 9 10

SW: BIND:

7

9

11 12

TRAINER /Pupil

Pupil

Teach

n/a

No

pupil

signal

Since at this early stage of programming a trainer 

system it is unlikely that an operational pupil transmitter 

is connected to the teacher transmitter, the transmitter 

responds immediately to the switches closed during the 

switch assignment process with appropriate visual and 

audible warning notices. You should therefore re-open 

the switch you have just assigned:

8 9 10

SW: BIND:

7

9



11 12

TRAINER /Teach

Pupil

Teach

n/a

Note:

The switch assignment just described also determines 

the transmitter used to issue the teacher and pupil 

functions, respectively. For this reason, a pupil 

transmitter must NEVER be assigned a switch on this 

menu. The header line therefore also switches from 

"TRAINER /Pupil" to "TRAINER /Teach" once a 

switch has been assigned.

The model to be controlled by the pupil must be 

programmed completely – i. e. with all its functions 

including trims and any mixer functions – in one of 
Detail program description - Control adjust 199

the model memories of the mx-20 HoTT teacher 

transmitter. The HoTT receiver of the model in question 

must also be "bound" to the teacher transmitter, since the 

latter ultimately controls the model, even in pupil mode.

ALWAYS ENSURE YOU SWITCH ON THE mx-20

HoTT teacher transmitter FIRST BEFORE PLUGGING 

THE CONNECTION CABLE INTO THIS UNIT. If you do 

not, the RF module will not be enabled.

The mx-20 HoTT teacher transmitter can be 

connected to any suitable pupil transmitter, even 

transmitters using the "traditional" 35/40 MHz range. 

If the pupil-side connection does NOT utilize a twopole DSC socket, however, but a three-pole trainer 

socket from the Graupner range (for example), then the 

fundamental precondition for a correct connection 

to a pupil transmitter is that the modulation type 

PPM (18 or 24) must ALWAYS be confi gured in the 

pupil transmitter, regardless of the modulation type 

used in the teacher transmitter. 

Pupil transmitter set-up

The model to be controlled by the pupil must be 

programmed completely – i. e. with all its functions including 

trims and any mixer functions – in one of the model 

memories of the teacher transmitter. If present, the HoTT 

receiver of the model in question must also be "bound" to 

the teacher transmitter. In principle, however, an mx-20

HoTT pupil transmitter can also be connected to a teacher 

transmitter from the "traditional" 35/40 MHz range.

Almost any transmitter with at least 4 control functions 

from previous and current Graupner series can be used 

as a pupil transmitter. More detailed information can be 

found in the RC main catalog and on the www.graupner.

de website.

If required, the pupil transmitter should be fi tted with the 

connection module for pupil transmitters. This is to be 

connected to the transmitter board in accordance with 

the supplied installation instructions. 

Information on the pupil modules required in each case 

can be found in Graupner's RC main catalog and on the 

www.graupner.de website.

The connection to the teacher transmitter is made using 

the appropriate lead; see the following double page.

The control functions of the pupil transmitter MUST 

act directly on the control channels, i. e. the receiver 

outputs, without intermediary mixers.

If you are using an "mc" or "mx" series transmitter, 

it is best to activate a free model memory with the 

required model type ("Fixed-wing" or "Heli"). Assign the 

model name "Pupil" and set up the stick mode (mode 1 

... 4) and "Throttle min. forward/back" to suit the pupil's 

preferences. All other settings are left at their default 

values, however. If you have selected the "Helicopter" 

model type, you must also set the throttle/ collective 

pitch direction and idle trim on the pupil transmitter. All 

other settings, including mixer and coupling functions, 

are confi gured exclusively on the teacher transmitter, 

which in turn transmits them to the model.

With "D" and "FM" type transmitters, you must also 

check the direction of servo rotation and stick mode, 

and adjust as necessary by swapping the corresponding 

leads. All mixers must also be switched off or set to 

"zero".

When assigning control functions, the usual conventions 

must be observed:

Channel Function

1 Motor throttle/collective pitch

2 Aileron/roll

3 Elevator/pitch-axis

4 Rudder/tail rotor

If you wish to transfer other control functions to the pupil 

transmitter in addition to the functions of the two dual 

axis sticks (1 ... 4), access the "Control adjust" menu 

on the pupil transmitter and assign transmitter controls to 

the inputs that correspond to the control numbers 5 ... 12

released on the teacher transmitter's "Teacher/pupil" menu.

Important:

• If you should forget to assign a transmitter 

control on the pupil side, then the affected servo 

or servos will remain in the center position when 

the transfer is made to the pupil transmitter.

• The pupil transmitter must always be operated in 

PPM mode, regardless of the RF connection type 

used between the teacher transmitter and the model.

• If the transmitter is connected using a DSC 

socket on the pupil side, ALWAYS leave the 

pupil transmitter's On/Off switch in the "OFF"

position: this is the only way to guarantee that 

no RF signal is sent from the pupil transmitter's 

transmitter module , even after the DSC lead has 

been plugged in.

Trainer mode operations

Both transmitters are connected to one another using 

a suitable lead (see summary on next page): The plug 

marked "M" (master) must be inserted into the socket 

on the teacher transmitter, and the plug marked "S" 

(student) into the pupil transmitter's socket. (Note that 

not all leads may have such "M" and "S" labeling.) 
200 Detail program description - Control adjust

Important notices:

• Check that the model aircraft is operational 

and check that all functions issue the correct 

commands BEFORE setting up trainer mode.

• The ends of the trainer lead, usually marked as 

either "S" or "M", terminate in a three-pole TRS 

jack. Do not insert these jacks into a DSC system 

socket, as it is not suitable for this application. 

The DSC socket is exclusively designed for a 

trainer lead with 2-pole TRS jacks.

Checking functionality

Activate the assigned trainer mode switch:

• The trainer mode system is working properly if the 

display now changes from "Teach" to "Pupil".

• If the center LED rapidly fl ashes blue/red, however, 

and the unit beeps at the same time, then the pupilteacher transmitter connection has been lost. 

The basic display also displays the following warning 

notice ...

No

pupil

signal

... and the left side of the screen display on the 

"Teacher/pupil" menu changes to show "-Pupil". 

In this case, all control functions are retained by 

the teacher transmitter automatically, regardless of 

switch position: this ensures the model is always 

under control.

Possible faults:

• Pupil transmitter not ready

• Interface in pupil transmitter not correctly connected 

in place of the RF module

• Cables connected wrongly: see right for cable 

connections

• Pupil transmitter not switched over to PPM (10, 18, 

24) mode

Other possible faults:

• Teacher transmitter not properly "bound" to HoTT 

receiver in training model

Trainer leads

4179.1 For trainer mode operation between any two 

Graupner transmitters equipped with a DSC 

socket (identifi able by the two-pole TRS 

jacks at each end of the lead)

3290.7 Trainer lead for connecting a teacher 

transmitter with DSC socket (e. g. mx-20 

HoTT) or a transmitter retrofi tted with the 

optional DSC module, order no. 3290.24) 

) to a Graupner pupil transmitter with an 

optoelectronic pupil socket (identifi able by 

the label "S" on the end with the three-pole 

TRS jack).

3290.8 Trainer lead for connecting a pupil 

transmitter with DSC socket (e. g. mx-20

HoTT) or a transmitter retrofi tted with the 

optional DSC module, order no. 3290.24) 

to a Graupner teacher transmitter with an 

optoelectronic teacher socket (identifi able by 

the label "M" on the end with the three-pole 

TRS jack).

For further details about the cables and modules for 

teacher and pupil transmitters mentioned in this section, 

please consult the respective transmitter handbook, 

the Graupner RC main catalog or the www.graupner.de 

website.
Detail program description - Control adjust 201

 Trainer mode with the mx-20 transmitter

Due to the continuous improvements made to the product range, please consult our website at www.graupner.de for the latest information

Teacher transmitter

with DSC socket

Teacher transmitter with teacher 

module order no. 

3290.2, 3290.19, 3290.22

Trainer lead 

order no. 4179.1

Trainer lead 

order no. 3290.8

M

Pupil transmitter mx-20 HoTT 

mx-12 HoTT, mx-16 HoTT, 

mx-20 HoTT

mc-19(s, iFS + HoTT) up to 

mc-24, mx-22(iFS), mx-24s

Pupil transmitter 

with DSC socket

Pupil transmitter with pupil module

order no. 3290.3, 3290.10, 3290.33

Trainer lead 

order no. 4179.1

Trainer lead 

order no. 3290.7

D 14, FM 414, FM 4014, FM 

6014, mc-10 ... mc-24, mx22(iFS), mx-24s

S

Teacher transmitter mx-20 HoTT

mx-12(s)HoTT, mx-16s/

iFS/HoTT, mx-20 HoTT, 

mx-22(iFS), mx-24s and, if 

equipped with DSC socket order 

no. 3290.24, mc-19(s + iFS), 

mc-22(s + iFS) and mc-24

Note:

The lists present the possible transmitters/transmitter 

combinations at the time of going to press. 

HoTT TT
202 Detail program description - Control adjust

 Wireless HoTT system

The mx-20 HoTT trainer mode system can also be 

operated wirelessly. To do so, the teacher transmitter 

must be "connected" to a pupil transmitter as described 

below. Prior to this, however, the training model's 

receiver must be bound to the PUPIL transmitter. This 

confi guration is possible between transmitters that have 

the "BIND:" option available on the "Teacher/pupil" 

menu.

Preparing for training mode

Teacher transmitter

The training model must be programmed completely – 

i. e. with all its functions including trims and any mixer 

functions – in one of the model memories of the HoTT 

teacher transmitter. The model to be used for training 

must therefore be under the complete control of the 

teacher transmitter. The fi nal step in preparation, 

however, is to bind the training model to the pupil 

transmitter. For a detailed description of the bind 

procedure, please consult pages 69 and 74.

Pupil transmitter

If you are using an "mc" or "mx" series transmitter, 

it is best to activate a free model memory with the 

required model type ("Fixed-wing" or "Heli"). Assign the 

model name "Pupil" and set up the stick mode (mode 

1 ... 4) and "Throttle (or collective pitch) min. forward/

back" to suit the pupil's preferences. All other options are 

left at their default values. All other settings, including all 

mixer and coupling functions, are confi gured exclusively 

on the teacher transmitter, which in turn transmits them 

to the model.

When assigning control functions, the usual conventions 

must be observed:

Channel Function

1 Motor throttle/collective pitch

2 Aileron/roll

3 Elevator/pitch-axis

4 Rudder/tail rotor

If you wish to transfer other control functions to the pupil 

transmitter in addition to the functions of the two dual 

axis sticks (1 ... 4), access the "Control adjust" menu 

on the pupil transmitter and assign transmitter controls to 

the inputs that correspond to the control numbers 5 ... 12

released on the teacher transmitter's "Teacher/pupil" menu. 

Important:

If you should forget to assign a transmitter control 

on the pupil side, then the affected servo or servos 

will remain in the center position when the transfer 

is made to the pupil transmitter.

Preparing the teacher and pupil transmitters

Once you have bound the training model to the pupil 

transmitter, now switch on the teacher transmitter. On 

both transmitters, use the arrow keys on the left or right 

touch pad, page to the "Teacher/pupil" menu option on 

the multi-function list:

Dual mixer

Tx. output swap

Telemetry

Basic settings

Fail-Safe adjust

Teacher / pupil

Swaschplate mixer

Tx. output swap

Telemetry

Basic settings

Fail-Safe adjust

Teacher / pupil

Briefl y tap the center SET key on the right touch pad to 

open this menu option:

TRAINER /Pupil

Pupil

Teach

2 3 4 5

SW: ––– BIND:

1

n/a

6

The screen image shown above shows the menu in its 

initial state: No transmitter controls have been released 

to the pupil ( ) and no switch is assigned ("SW: ---" 

bottom left in the screen image).

Pupil transmitter

Using the arrow keys on the left or right touch pad, move 

the marker frame to the "BIND" input fi eld. If you can 

see a switch to the right of "SW:", then this MUST fi rst 

be erased, see screen image:

2 3 4 5

SW: ––– BIND:

1 6

TRAINER /Pupil

Pupil

Teach

n/a
Detail program description - Control adjust 203

Teacher transmitter

Up to twelve control functions of the teacher transmitter 

"Teach" can be transferred to the pupil transmitter 

"Pupil", either individually or in any combination. 

The lower display line, named "Teach", therefore refers 

to the transmitter controls permanently connected 

to inputs 1 ... 4 (dual axis stick functions for fi xed-wing 

and heli model) and the CTRL 6 to 10 controls that are 

assigned or can be assigned to inputs 5 ... 12 (optionally 

fl ight phase-specifi c) on the "Control adjust" menu.

Use the arrow keys  on the left or right touch pad 

to select the transmitter controls from 1 to 12 () to 

transfer to the pupil and then briefl y tap the center SET

key on the right touch pad in each case, so as to switch 

between "Teach" (Teacher)" ( ) and "Pupil" 

( ):

2 3 4 5

SW: ––– BIND:

1 6

TRAINER /Pupil

Pupil

Teach

n/a

To be able to carry out the transfer, you must now assign 

a trainer mode switch. To do so, use the arrow keys on 

the left or right touch pad to move the marker frame 

to the bottom left, to the right of "SW:" now assign a 

switch as described in the section "Assigning transmitter 

controls, switches and control switches" (page 52).

Preferably, you should utilize one of the two momentary 

switches, SW 1 or SW 9, so as to be able to revert 

control back to the teacher transmitter at any time:

8 9 10

SW: BIND:

7

9

11 12

TRAINER /Pupil

Pupil

Teach

n/a

No

pupil

signal

Since at this stage of programming the wireless trainer 

system no connection yet exists to a pupil transmitter, 

the transmitter responds immediately to the switches 

closed during the switch assignment process with 

appropriate visual and audible warning notices. You 

should therefore re-open the switch you have just 

assigned:

8 9 10

SW: BIND:

7

9



11 12

TRAINER /Teach

Pupil

Teach

n/a

Note:

The switch assignment just described also determines 

the transmitter used to issue the teacher and pupil 

functions, respectively. For this reason, a pupil 

transmitter must NEVER be assigned a switch on this 

menu. The header line therefore also switches from 

"TRAINER /Pupil" to "TRAINER /Teach" once a 

switch has been assigned.

Using the arrow keys on the left or right touch pad, now 

move the marker frame to the right, to "BIND: n/a":

8 9 10

SW: BIND:

7

9



11 12

TRAINER /Teach

Pupil

Teach

n/a

Binding the pupil transmitter to the teacher 

transmitter

Note:

During the bind process, the two transmitters should 

not be very far apart. You may fi nd you need to change 

the positions of the transmitters and then start the bind 

process again.

Initiate the "BINDING" process from the pupil transmitter 

by tapping the center SET key on the right touch pad ...

8 9 10

SW: BIND:

7

9



Binding

–

11 12

TRAINER /Pupil

Pupil

Teach

... and repeat this immediately on the teacher 

transmitter:

8 9 10

SW: BIND:

7

9



Binding

11 12

TRAINER /Teach

Pupil

Teach

As soon as this process is complete, both screens will 
204 Detail program description - Control adjust

show "ON" instead of the fl ashing "BINDING":

8 9 10

SW: BIND:

7

9



ON

–

11 12

TRAINER /Pupil

Pupil

Teach

8 9 10

SW: BIND:

7

9



ON

11 12

TRAINER /Teach

Pupil

Teach

You can return to the basic display on both screens and 

start the training session after carefully checking all of 

the relevant functions. 

If neither transmitter or only one transmitter displays 

"ON", this means the binding process has failed: try 

changing the positions of both transmitters and then 

repeat the entire procedure.

Important notice:

Check that the model aircraft is operational and 

check that all functions issue the correct commands 

BEFORE setting up trainer mode.

During the ...

Training session

... the teacher and pupil can maintain a more "relaxed" 

distance from one another. The "reach of signal" 

(max. 50 m) should not be exceeded under any 

circumstances, however, nor should anyone else be 

standing between the teacher and the pupil, since these 

persons could reduce the connection range of the return 

channel used by the two transmitters. Furthermore, you 

should remember that the return channel assigned for 

wireless trainer mode functionality is normally used for 

telemetry connections: accordingly, it will not be possible 

to transmit any model telemetry data.

In this operating mode, the basic display of the teacher 

transmitter is as shown below ...

GRAUBELE

#01

2:22h

Stop

Flt

«Normal »

K78

0:00

0:00

5.5V

5.2V

P

HoTT

RF –Teach

... and the pupil transmitter's display will look something 

like this:

PUPIL

#01

3:33h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

4.9V HoTT

RF –Pupil

If, however, the connection between the teacher and 

pupil transmitters should be lost during the training 

session, then the teacher transmitter will automatically 

assume control of the model.

If the trainer mode switch is in the "Pupil" position when 

connectivity is lost, then the center LED on the teacher 

transmitter will fl ash blue/red while the signal is lost and 

audible warning signals will also be given. The basic 

display also displays the following warning notice:

No

pupil

signal

If only the character string "HF –" starts fl ashing on 

the transmitter's basic display, however, and (quieter) 

audible warning signals are given, the pupil signal has 

still been lost, but the trainer mode switch is set to the 

"Teacher" position. 

In both cases, your fi rst step should be to reduce the 

distance between the two transmitters. If this does not 

help, then you should land immediately and establish 

the cause.

If both transmitters are operational and the receiver 

system is switched off, then the teacher transmitter's 

basic display will show the "familiar" instead of the 

two icons . The antenna icon will also fl ash and an 

audible warning signal will sound twice per second.

Resuming trainer mode

If you switch off one or both transmitters during the 

session – for whatever reason – then the basic display 

of the transmitter(s) shows the following question after 

being switched back on:

Please select

trainer link?

ACT INH

If you either confi rm "INH" by tapping the center SET

key on the right touch pad, or alternatively wait for 

approx. two seconds until the message disappears, 

then you will reset the transmitter in question back to 

its "normal" operating mode. You will then have to reestablish a connection between the teacher and pupil 

transmitters.
Detail program description - Control adjust 205

If, on the other hand, you use the arrow keys on the left 

or right touch pad to select "ACT" ... 

Please selcet

trainer link?

ACT INH

... and confi rm this selection by tapping the center SET

key on the right touch pad, then the existing teacher 

connection is restored. The same approach is used if the 

transmitter is confi gured as a pupil transmitter.
206 Detail program description - Control adjust

Using the arrow keys on the left or right touch pad, page 

to the menu option "Tx. output swap" on the multifunction list: 

Dual mixer

Telemetry

Basic settings

Fail-safe adjust

Teacher / Pupil

Tx. output swap

Swashplate mixer

Telemetry

Basic settings

Fail-safe adjust

Teacher / Pupil

Tx. output swap

Briefl y tap the center SET key on the right touch pad to 

open this menu option.

Tx. output swap

To achieve maximum fl exibility regarding receiver socket 

assignment, the mx-20 HoTT program offers you the 

option of swapping servo outputs 1 to 12 as you please.

This option lets you distribute the transmitter's 12 

"control channels" to any of the transmitter outputs 1 

... 12. If you do, you must remember that the "Servo 

display" screen – accessible from almost any menu 

option by simultaneously tapping the  and  keys 

on the left touch pad – refers exclusively to the "control 

channels" as preset by the receiver socket assignment: 

it therefore does NOT take any output swaps into 

account.

 Tx. output swap

Swapping the outputs on the transmitter

Tx Ch

Tx Ch

Tx Ch

Tx Ch

1

2

3

4

1

2

3

4

Output

Output

Output

Output

TRANSMITTER OUTPUT

SEL

Use the arrow keys  on the left or right touch pad to 

select the channel/output combination that you wish to 

change and then briefl y tap the center SET key on the 

right touch pad. You can now use the right arrow keys 

to assign your selected (control) channel to the desired 

output, confi rming this with the SET key ... 

2

3

4

1

2

3

4

SEL

Tx Ch 6

Tx Ch

Tx Ch

Tx Ch

Output

Output

Output

Output

TRANSMITTER OUTPUT

... or, by tapping the arrow keys  or  on the 

right touch pad at the same time (CLEAR), you can 

restore the original assignment. 

Any subsequent changes, such as servo travel 

adjustments, Dual Rate / Expo, mixers etc., must 

always be performed in accordance with the original 

receiver socket assignment!

Example:

In the mx-20 HoTT helicopter program, the outputs 

for a collective pitch servo and the throttle servo are 

swapped around, compared to some older GRAUPNER/

JR mc units. The throttle servo now occupies transmitter 

output "6" and the collective pitch servo output "1". 

Perhaps, however, you wish to retain the previous 

confi guration? In this case, you will swap over channels 

1 and 6 as appropriate, so that (control) channel 6 is 

located on output 1 and vice versa – as shown above: 

Note:

The "Channel Mapping" (channel assignment) function 

integrated into the telemetry menu on the 

mx-20HoTT receiver can also be used to distribute up 

to 12 control channels from the transmitter to multiple 

receivers. The function can also be used to map the 

exact same control function to multiple receiver outputs: 

this can be used to confi gure two servo controls per 

aileron surface instead of just the one, for example, etc. 

To keep controls manageable, however, we strongly 

recommend using only one of the options at a time. 
Detail program description - Control adjust 207
208 Detail program description - Control adjust

 Telemetry

The transmitter and receiver data as well as the data 

for optional telemetric sensors (see Appendix) can be 

viewed and programmed in the "Telemetry" menu.

The receiver data is transmitted to the transmitter 

through the return channel integrated in the HoTT 

receiver.

One telemetry sensor can be connected through the 

telemetry input to each of the receivers GR-12S HoTT 

(Order No. 33505), GR-12 HoTT (Order. No. 33506), 

GR-16 (Order. No. 33508) and GR-24 HoTT (Order. No. 

33512).

The corresponding "Telemetry" menus always keep 

these and future receivers up to date with the latest 

version and ensures enhancement with future functions 

or languages.

Note:

After registering your product at https://www.graupner.

de/de/service/produktregistrierung you are automatically 

informed of new updates. 

Important information:

• This manual depicts the available functions at the 

time of printing.

• As already indicated in the section "Connection 

of multiple receivers" on page 69 and 74, multiple 

receivers can be connected as necessary for each 

model. During the later operation, however, only 

the receiver which was activated in the line "TEL.

EMPF." of the "Telemetry" menu, is capable 

of establishing a telemetric connection to the 

transmitter! However, that also means the inverse, 

that only this receiver can be addressed through the 

Telemetry menu! If necessary, therefore, the selection 

must be changed before settings can be made on a 

specifi c receiver:

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV BIND. 1

• When adjusting the settings of the remote 

control, make absolutely sure that the transmitter 

antenna is always far enough away from the 

receiver antennae! To be on the safe side, keep 

them at least one meter apart. Otherwise you 

run the risk of a faulty connection for the return 

channel and malfunction as a result.

• Since the telemetric data between transmitter and 

receiver is only exchanged after the fourth data 

package, the data transmission requires a certain 

amount of time for technical reasons, so the reaction 

to the operating keys and changes to settings take 

place with a delay. Therefore, the delay is not due to 

an error.

• Programming on the model or on sensors may only 

take place if the model is on the ground. Only carry 

out the settings with the motor switched off and 

the battery disconnected! Otherwise, undesired 

programming cannot be ruled out.

 For example, a servo test initiated accidentally 

could cause the model to crash and cause personal 

injury and/or property damage. Observe the safety 

instructions on pages 4-7 of this manual and the 

individual respective manuals.

• All settings (such as fail-safe, servo direction 

reversal, servo travel, mixer and curve settings, etc.) 

made through the "Telemetry" menu are only saved 

in the receiver and, therefore, are adopted along with 

it in the course of the conversion of a receiver to a 

different model, if applicable. Therefore, to be on the 

safe side, re-initialize your HoTT receiver if you want 

to use the receiver in a different model; see "Reset" 

on page 43.

• Only program the servo direction reversal, servo 

travel, mixer and curve settings through the mx-20-

specifi c standard menus "Servo adjustment" page 

90, "Dual Rate / Expo" page 108 and 112, "Channel 

1 curve" page 116 and 119, etc. Otherwise, the 

settings superimpose one another, which can lead to 

complexity or even problems in the later operation.

• With the channel assignment function of the 

Telemetrymenu integrated in themx-20 HoTT, control 

functions can also be assigned with distribution to 

multiple receivers or multiple receiver outputs can 

even be assigned with the same control function, 

such as the ability to activate two servos per aileron 

instead of only one individual servo, etc. We also 

recommend exercising extreme during the 

programming.
Detail program description - Control adjust 209

Telemetry

The menus comprised under the heading "Telemetry" 

can be called up from the default display of the 

transmitter mx-20 HoTT by pressing the central ESC

key of the left touch pad for approx. one second. The 

same menus can, like other menus of the transmitter, 

also be opened in the multifunction list by pressing the 

central SETkey on the right touch pad:

Dual mixer

Basic settings

Fail-safe adjust

Teacher / pupil

Tx. output swap

Telemetry

Swashplate mixer

Basic settings

Fail-safe adjust

Teacher / pupil

Tx. output swap

Telemetry

Basic operation

The operation of the "Telemetry" is essentially the 

same as that of the other menus of the transmitter 

mx-20 HoTT. The few differences are described in the 

following:

You can switch between the individual pages of the 

Telemetry menu with the arrow keys  of the left 

or right touch pad. The corresponding directional 

indications can be found at top right of each display 

page in the form of angled brackets (<>); see the 

following fi gures. If only one angled bracket is visible, 

you are on either the fi rst or last respective page. In this 

case, changing pages is only possible in the indicated 

direction.

Menu lines in which parameters can be changed are 

identifi ed with the aforementioned angled bracket (>). By 

pressing the arrow keys of the  of the left or right 

tough pad, the ">" pointer jumps one line forward or one 

line back. Lines which you cannot jump to cannot be 

changed.

In order to change a parameter, briefl y press the 

central SET key of the right touch pad (the parameter 

is represented inversely), change the value within the 

permissible adjustment range with the arrow keys of the 

right touch pad and adopt the value by pressing the SET

key again. By briefl y pressing the central ESC key of the 

left4-way pad, you return to the starting position.

Now select the desired submenu with the arrow keys 

 of the left or right touch pad. However, if the 

message ...

CAN‘T

RECEIVE

DATA

OK

... appears instead of the desired submenu after 

pressing the central SET key of the right touch 

pad, no connection has been established to the 

receiver. Therefore, switch on your receiver system 

or, if applicable reconnect the addressed receiver as 

described on page 68 and 74 or activate it as described 

under "Important Notices" on the previous page.

On the fi rst display page of the submenu overwritten 

with ...

 RX DATAVIEW

...

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV rcv ch1

... no settings can be made. This page is only provided 

for information:

RX DATAVIEW

S–STR100% R–TEM.+28°C

L PACK TIME 00010msec

R-VOLT :05.0V

L.R-VOLT:04.5V

S–QUA100%S–dBM–030dBM

SENSOR1 :00.0V 00°C

SENSOR2 :00.0V 00°C

Value Explanation

S-QUA Signal quality in %

S-dBm Reception power in dBm

S-STR Signal strength in %

R-TEM. Receiver temperature in °C

L PACK TIME Indicates the time in ms in which the 

longest data package is lost during the 

transmission from the transmitter to the 

receiver

R-VOLT Current operating voltage of the 

receiver in volts

 SETTINGS/DISPLAYS
210 Detail program description - Control adjust

L.R-VOLT Lowest operating voltage of the 

receiver since it was last turned on, in 

volts

SENSOR1 Indicates the values of the optional 

telemetric sensor 1 in volts and °C

SENSOR2 Indicates the values of the optional 

telemetric sensor 2 in volts and °C

Signal quality (S-QUA)

The signal quality (S-QUA) is sent "live" over the return 

channel of the receiver to the transmitter and indicates 

the signal strength in %.

Reception power (S-dbm)

The reception power (S-dbm) is indicated with negative 

values, which means a value of zero is the maximum 

value (= best reception) and the lower the values are, 

the poorer the reception power! The range test before 

operation, among other things, is important for this.

Note:

With negative numbers the evaluation of a number is 

reversed: The higher the number following the minus 

symbol, the lower the value is. Therefore, a reception 

power of -80 dBm, for example , is poorer than one with 

-70 dBm.

Perform the range test as described on page 71 and 

77 before each fl ight and, in doing so, simulate all servo 

movements which also take place during the fl ight. The 

range must be at least 50 m on the ground with the 

range test activated. At this distance, the value shown 

under "S-dBm" in the "RX DATAVIEW" display may 

not be greater than -80 dBm in order to guarantee safe 

operation. Your should never be operated with a lower 

value (e. g. -85 dBm). Check the installation of the 

receiver system and the position of the antenna.

The reception power should not drop below -90 dBm 

during operation. Otherwise, reduce the distance of the 

model. Normally, however, the acoustic range warning 

(peep tone interval 1 s) is triggered before this value is 

reached in order to guarantee safe operation.

Signal strength (S-STR)

The signal strength (S-STR) is displayed in %. In 

general, an acoustic range warning (peep tone interval 

1 s) is issued as soon as the receiver signal becomes 

too week in the return channel. However, since the 

transmitter has a signifi cantly higher transmission power 

than the receiver, the model can still be safely operated. 

For the sake of safety, the distance to the model should 

be reduced until the warning tone goes silent again.

Receiver temperature (R-TEM.)

Make sure that your receiver remains within the 

permissible temperature range during all fl ight 

conditions (ideally between -10 and 55 °C).

The receiver temperature limit at which a warning is 

issued can be adjusted in the submenu "RX SERVO 

TEST" under "ALARM TEMP+" (50 ... 80 °C and 

"ALARM TEMP" (-20 ... +10 °C). When the value 

is undercut or exceeded, an acoustic signal follows 

(continuous peep tone) and "TEMP.E" appears at the 

top right of all "RX" receiver submenus. In addition, 

the parameter "R-TEM" is shown inversely on the "RX 

DATAVIEW" display page.

Data packages (L PACK TIME)

Indicates the longest time span in ms in which data 

packages are lost in the transmission from the 

transmitter to the receiver. In practice, that is the longest 

time span in which the remove control system has 

entered into fail-safe mode.

Receiver operating voltage (R-VOLT)

Always check the operating voltage of the receiver. 

Never operate or even start your model if the operating 

voltage is too low.

The receiver low voltage warning can be adjusted 

between 3.0 and 6.0 volts in the submenu "RX SERVO 

TEST" under "ALARM VOLT". If this range is undercut, 

an acoustic signal is issued (repeating double peep tone 

(long/short)) and "VOLT.E" appears at the top right of 

all "RX" receiver submenus.| In addition, the parameter 

"R-VOLT" is shown inversely in the "RX DATAVIEW" 

submenu.

The current receiver battery voltage is also displayed in 

the default display, see page 24.

Minimum receiver operating voltage (L.R-VOLT)

"L.R-VOLT" indicates the minimum operating voltage of 

the receiver since the last time it was switched on.

If this voltage should deviate signifi cantly from the 

current "R-VOLT" operating voltage, the receiver battery 

may be too heavily encumbered by the servos. The 

consequence is voltage drops. In this case, use a more 

powerful voltage supply in order to achieve maximum 

operational safety.

Sensor 1 + 2

Indicates the values of the optional telemetric sensors 

1 and 2 in volts and °C, if applicable. A description of 

these sensors can be found in the appendix.
Detail program description - Control adjust 211

 RX SERVO

RX SERVO

REVERSE : OFF

CENTER : 1500μsec

TRIM : –000μsec

LIMIT– : 150%

OUTPUT CH: 01

LIMIT+ : 150%

PERIOD : 20msec

Before any programming on this display page, 

observance of the notices on page 208 is mandatory.

Value Explanation Possible settings

OUTPUT CH Channel selection 1 ... depending on 

receiver

REVERSE Servo reversal OFF / ON

CENTER Servo center in μs if active (inverse), 

dependent on 

control position

TRIM Trim position in μs 

deviating from the 

CENTER position

-120 ... +120 μs

LIMIT– Travel limit for % 

servo travel

30 ... 150 %

LIMIT+ Travel limit for % 

servo travel

30 ... 150 %

PERIOD Cycle time in ms 10 or 20 ms

OUTPUT CH (channel selection)

If applicable, select the line "OUTPUT CH" with the 

arrow keys. Press the SET key of the right touch pad. 

The value fi eld is shown inversely. Now set the desired 

channel (e. g. 01) with the arrow keys of the right touch 

pad. The following parameters are always based on 

the channel set here.

Reverse (servo reversal)

Set the rotational direction of the servo connected to the 

selected servo channel: ON / OFF

CENTER (servo center)

The active value fi eld (inverse representation) in the 

"CENTER" line shows the current impulse time of the 

control channel selected in the "OUTPUT CH" line in μs. 

The displayed value depends on the current position 

of the control infl uencing this control channel and, if 

applicable, the position of its trimming.

A channel impulse time of 1500 μs corresponds to the 

standard center position and thus the conventional 

servo center.

In order to change this value, select the "CENTER" line 

and press the SET key. Now move the corresponding 

control, joystick and/or trim lever to the desired position 

and save the current control position by pressing the 

SET key again. This position is saved as the new neutral 

position.

TRIM (trim position)

In the "TRIM" line" you can carry out the fi ne adjustment 

of the neutral position of a servo connected to the 

control channel selected in the "OUTPUT CH" line using 

the arrow keys of the right touch pad in 1 μs increments. 

The value in the "CENTER" line can be adjusted by the 

TRIM value set here in a range of ±120 μs. 

Factory setting: 0 μs.

LIMIT–/+ (travel limit -/+)

This option is provided for the adjustment of a sidedependent limit (limiting) of the servo travel (rudder 

throw) of the servo connected to the control channel 

selected in the "OUTPUT CH" line. 

The setting for both directions takes place in a range of 

30 ... 150 %.

Factory setting: 150 % each.

PERIOD (cycle time)

In this line you determine the time interval of the 

individual channel impulse. This setting is adopted for all 

control channels.

With the use of only digital servos, a cycle time of 10 ms 

can be set.. 

In mixed operation or with use of only analog servos, 

20 ms should absolutely be set, because the latter can 

otherwise be "overstrained" and react with "shaking" or 

"quivering" as a result.

 RX FAIL SAFE

RX FAIL SAFE

INPUT CH: 01

MODE : HOLD

F.S.POS. : 1500μsec

DELAY : 0.75sec

OUTPUT CH: 01

FAIL SAFE ALL: NO

POSITION : 1500μsec

The description of this menus necessitates a few words 

of warning in advance:

"Do nothing" is the absolute worst thing to be done in 

this regard. "HOLD" is prescribed in the base setup 

model of the HoTT receiver.

In the event of a failure, in the best case scenario the 

model fl ies straight ahead for an indefi nite amount of 

time and then hopefully "lands" somewhere without 

causing signifi cant damage! However, if something like 

this happens in the wrong place at the wrong time, the 
212 Detail program description - Control adjust

model may become uncontrollable and "tear" across the 

fl ight fi eld completely out of control, putting the pilot and 

spectators at risk.

Therefore, it would obviously be benefi cial to program 

the the function "Motor off" at the very least, in order to 

prevent such risks. If necessary, seek the advice of an 

experienced pilot in order to fi ne a "logical" setting for 

your model.

And then another brief notice regarding the three 

possible versions of the mx-20 HoTT transmitter for 

the setting of Fail Safe:

The easiest, and recommended, way to fail-safe settings 

is the use of the "Fail Safe" menu, which can be 

reached from the multifunction list, see page 196.

Similarly, in order to achieve the same result somewhat 

more laboriously, the "FAIL SAFE ALL" option described 

on the following pages is also available.

In addition, there are the relatively elaborate methods 

of the of the individual adjustment using the options 

"MODE", "F.S.Pos." and "DELAY". The description of 

these variants begins with the "MODE" option further 

below.

Value Explanation Possible settings

OUTPUT CH Output channel 

(servo connection 

of the receiver)

1 ... depending on 

receiver

INPUT CH Input channel 

(channel 

coming from the 

transmitter)

1 ... 12

MODE Fail-Safe mode HOLD

FAIL SAFE

OFF

F.S.POS. Fail-safe position 1000 ... 2000 μs

DELAY Reaction time 

(delay)

0.25, 0.50, 0.75 

and 1.00 s

FAIL SAFE 

ALL

Save of the Failsafe

Positions of all 

control channels

NO / SAVE

POSITION Display of the 

saved Fail-safe 

position

Between approx 

1000 and 2000 μs

OUTPUT CH (servo connection)

In this line you select the respective OUTPUT CH (servo 

connection of the receiver) to be set.

INPUT CH ( selection of the input channel)

As already mentioned on page 208, the control functions 

of the mx-20 HoTT transmitter can be arbitrarily 

distributed to multiple receivers, if necessary, or even 

assigned to multiple receiver outputs with the same 

control function. For example, this might be used in 

order to be able to control two servers for each aileron 

fl ap or an oversized rudder with linked servos instead of 

an individual servo. 

Distribution to multiple HoTT receivers, in turn, offers the 

advantage of not having to use a long servo cable, e. g. 

for large models. In this case, bear in mind that only the 

receiver selected in the line "TEL.EMPF." through the 

"Telemetry" menu can be addressed!

The 12 control channels (INPUT CH) of the mx-20

HoTT can be appropriately managed through so-called 

"Channel Mapping" (channel assignment) whereby 

a different control channel is assigned to the servo 

connection selected in the OUTPUT CH line for the 

receiver in the INPUT CH line. ATTENTION: If, for 

example, you have specifi ed "2AIL" for the transmitter 

side in the line "Aile/fl aps" in the "Base setup model" 

menu, the Control function 2 (Aileron) is already 

distributed to the Control channels 2 and 5 for the left 

and right aileron. The corresponding INPUT CH of 

the receiver, which must also be mapped, would be 

the channels 02 and 05 in this case; see the following 

example.

Examples:

• You would like to control each aileron fl ap with two or 

more servos for a large model: 

• You would like to control each aileron fl ap with two or 

more servos for a large model: 

Assign one of the two standard aileron control 

channels 2 or 5 as INPUT CH to the corresponding 

OUTPUT CH (servo connections) depending on the 

left or right bearing surface. 

• You would like to control the rudder with two or more 

servos for a large model: 

Assign the same INPUT CH (control channel) to the 

corresponding OUTPUT CH (servo connections). In 

this case, this is the standard rudder channel 4.

MODE

The settings of the options "MODE", "F.S.Pos." and 

"DELAY" determine the behavior of the receiver in the 

event of a failure in the transmission from transmitter to 

receiver.

The setting programmed under "MODE" is always based 
Detail program description - Control adjust 213

on the channel set in the OUTPUT CH line.

The factory setting for all servos is "HOLD".

For each selected OUTPUT CH (servo connection of the 

receiver) you can choose between:

• FAI(L) SAFE

With this selection, in the event of a failure the 

corresponding servo moves to the position shown in 

the "POSITION" line for the remainder of the failure 

until the "Delay time" set in the "DELAY" line has 

lapsed.

• HOLD

With a setting of "HOLD", in the event of a failure 

the servo maintains the last correctly received servo 

position for the duration of the failure.

• OFF

With a setting of "OFF", in the event of a failure 

the receiver discontinues the retransmission 

of (temporarily stored) control impulses for the 

respective servo output for the duration of the failure. 

In other words, the receiver switches the impulse line 

"off".

ATTENTION: Analog servos and even some digital 

servos no longer put up any resistance against the 

previous control pressure during the failure of the 

control impulse and are more or less pushed out of 

their position as a result.

F.S.POS. (Fail-Safe position)

For each OUTPUT CH (servo connection of the 

receiver), set the respective servo position, which the 

servo should assume in the event of a failure in "FAI(L) 

SAFE" mode, in the line "F.S.POS." after activation of 

the value fi eld (inverse representation) by pressing the 

SET key in the right touch pad and with the arrow keys 

of the right touch pad. The adjustment takes place in 

10-μs increments.

Factory setting: 1500 μs (servo center).

Important notice:

The function "F.S.POS." has an additional meaning in all 

three modes, "OFF", "HOLD" and "FAI(L) SAFE" in the 

event that the receiver is switched on, but (still) does not 

receive a valid signal. 

The servo immediately travels to the fail-safe position 

predefi ned in the "Position" line. In doing so, the landing 

gear, for example , is is prevented from retracting of the 

receiver is accidentally switched on while the transmitter 

is switched off. In normal model mode, on the other 

hand, the corresponding servo behaves in accordance 

with the set "MODE" in the event of a failure.

DELAY (fail-safe reaction time or delay)

Here you adjust the delay time after which the servos 

should move to their predetermined positions in the 

event of a signal interruption. This setting is adopted 

for all channels and only pertains to the servos 

programmed to the "FAI(L) SAFE" mode. 

Factory setting: 0.75 s.

FAIL SAFE ALL (global fail-safe setting)

This submenu allows you to determine the fail-safe 

positions of Servos with a "push of a button" in a similar 

manner to the "Fail Safe" described on page 196.

Switch to the line "FAIL SAFE ALL" and activate the 

value fi eld by pressing the central SET key of the right 

touch pad. "NO" is represented inversely. Then adjust 

the parameter to "SAVE" with one of the arrow keys of 

the right touch pad. Now, using the operating elements 

of the transmitter, move all servos to the desired failsafe position you assigned or want to assign in the line 

"MODE" "FAI(L) SAFE". The current position of the 

control for the channel which was just set is shown in 

the bottom "Position" line:

RX FAIL SAFE

INPUT CH: 01

MODE : FAI-SAFE

F.S.POS. : 1500μsec

DELAY : 0.75sec

OUTPUT CH: 01

POSITION : 1670μsec

FAIL SAFE ALL: SAVE

After pressing the central SET key of the right touch 

pad, the display switches back from "SAVE" to "NO". 

The saved the positions of all servos affected by this 

measure and adopted them in parallel to the line 

"F.S.Pos." and the display then immediately shows 

the following for the current OUTPUT CH (servo 

connection):

RX FAIL SAFE

INPUT CH: 01

MODE : FAI-SAFE

F.S.POS. : 1670μsec

DELAY : 0.75sec

OUTPUT CH: 01

POSITION : 1670μsec

FAIL SAFE ALL: NO

Switch off the transmitter and check the fail-safe 

positions based on the servo throws. 

"Fail Safe" in combination with "Channel Mapping"

In order to ensure that the mapped servos – that is 

to say servos which are controlled from a common 

control channel (INPUT CH) – react the same way even 

in the event of a failure, the corresponding settings of 

the INPUT CH determine the behavior of the mapped 

servos!!! 
214 Detail program description - Control adjust

Therefore, the servo connections 6, 7 and 8 of a 

receiver are mapped with one another, whereby the 

OUTPUT CH (servo connections) 06, 07 and 08 are 

assigned as INPUT CH of the same respective control 

channel "04"...

RX FAIL SAFE

INPUT CH: 04

MODE : OFF

F.S.POS. : 1670μsec

DELAY : 0.75sec

OUTPUT CH: 06

POSITION : 1670μsec

FAIL SAFE ALL: NO

RX FAIL SAFE

INPUT CH: 04

MODE : OFF

F.S.POS. : 1230μsec

DELAY : 0.75sec

OUTPUT CH: 07

POSITION : 1670μsec

FAIL SAFE ALL: NO

RX FAIL SAFE

INPUT CH: 04

MODE : HOLD

F.S.POS. : 1770μsec

DELAY : 0.75sec

OUTPUT CH: 08

POSITION : 1670μsec

FAIL SAFE ALL: NO

... the INPUT CH 04 determines the fail-safe behavior of 

these three servos connected to the control channel 4 

completely independently of the individual settings of the 

respective OUTPUT CH: 

RX FAIL SAFE

INPUT CH: 04

MODE : FAI-SAFE

F.S.POS. : 1500μsec

DELAY : 0.75sec

OUTPUT CH: 04

POSITION : 1500μsec

FAIL SAFE ALL: NO

This is also the case, for example, if this is mapped with 

INPUT CH 01:

RX FAIL SAFE

INPUT CH: 01

MODE : FAI-SAFE

F.S.POS. : 1500μsec

DELAY : 0.75sec

OUTPUT CH: 04

POSITION : 1500μsec

FAIL SAFE ALL: NO

In this case, the servo connection 04 would, in turn, 

react according to the fail-safe settings of CH 01.

The reaction or delay time set in the "DELAY" line, on 

the other hand, always applies uniformly for all channels 

set to "FAI(L) SAFE".

 RX FREE MIXER

RX FREE MIXER

MASTER CH: 00

SLAVE CH : 00

S–TRAVEL–: 100

S–TRAVEL+: 100

MIXER : 1

RX WING MIXER

TAIL TYPE: NORMAL

Value Explanation Possible settings

MIXER Mixer selection 1, 2 or 3

Value Explanation Possible settings

MASTER CH Signal source or 

source channel

0, 1 ... depending 

on receiver

SLAVE CH Target channel 0, 1 ... depending 

on receiver

S-TRAVEL– Admix negative 0 ... 100 %

S-TRAVEL+ Admix positive 0 ... 100 %

RX WING 

MIXER

Tail unit type 

(TAIL TYPE)

NORMAL,

V-TAIL (V-LW)

ELEVON 

(vertical/horizontal 

mixer for delta and 

fl ying wing)

MIXER

Up to three mixers can be programmed simultaneously. 

Switch between Mixer 1, Mixer 2 and Mixer 3 through 

"MIXER".

The following settings in this display always for just the 

mixer selected in the "MIXER" line.

Important notice:

If you have already programmed mixer functions 

in the "Wing mixer" or "Free mixer" menu, make 

absolutely sure that these mixers do not overlap 

with those in the menu "RX FREE MIXER"!

MASTER CH ("from")

According to the same principles described in the 

section "Free mixer" on page 180, the signal applied 

at the MASTER CH (signal source or source channel) 

is mixed to a variable extent to the SLAVE CH (target 

channel). 

Select "00" if no mixer should be set.
Detail program description - Control adjust 215

SLAVE CH ("to")

The signal of the MASTER CH (source channel) is 

mixed proportionally to the SLAVE CH (target channel). 

The degree of mixture is determined by the percentages 

entered in the lines "TRAVEL–" and "TRAVEL +".

Select "00" if no mixer should be set.

TRAVEL–/+ (proportion of the admix in %)

With the settings of these two lines the percentage of 

the admix is specifi ed in relation to the MASTER signal 

separately for each direction.

RX WING MIXER TAIL TYPE (tail unit type)

The following model types are also available in the "Tail" 

line of the "Model type" menu, page 82 and should, 

preferentially, be pre-set there. In this case, always leave 

the TAIL TYPE set to NORMAL.

However, if you would prefer to use the mixer integrated 

in the receiver, you can select the already preadjusted 

mixer functions for the corresponding model type:

• NORMAL

This setting corresponds to the classic aircraft type 

with rear tail unit and separate rudder and elevator. 

No mixing function is necessary for this model type.

• V-TAIL (V-tail unit)

With this model type the elevator and rudder control 

functions are connected, so that each of the two 

tail unit fl aps – each controlled with a separate 

servo – assume both the elevator and rudder function. 

The servos are normally connected at the receiver 

as follows:

OUTPUT CH 3: Left V-tail servo

OUTPUT CH 4: Right V-tail servo

If the servo's direction of rotation is incorrect, please 

observe the notices on page 57.

• ELEVON (delta/fl ying wing models)

The servos connect at the outputs 2 and 3 assume 

the aileron and elevator function. The servos are 

normally connected to the receiver as follows:

OUTPUT CH 2: Left horizontal/vertical

OUTPUT CH 3: Right horizontal/vertical

If the servo's direction of rotation is incorrect, please 

observe the notices on page 57.

 RX CURVE

RX CURVE

 TYPE : B

CURVE1 CH : 02

 TYPE : B

CURVE2 CH : 03

 TYPE : B

CURVE3 CH : 04

Value Explanation Possible settings

CURVE1, 2 

or 3 CH

Channel 

assignment of the 

respective curve 

setting 

1 ... depending on 

receiver

TYPE Curve type A, B, C

see fi gure

Expo = +100%

–100% +100% 0 –100% 0 +100%

Expo = –100%

TYPE A

–100% +100% 0 –100% 0 +100%

linear

–100% +100% 0 –100% 0 +100%

TYPE B

TYPE C

DR = 125% DR = 70% Servo travel

Control travel

Servo travel

Control travel

Servo travel

Control travel

Normally a non-linear control function, if applicable, is 

used for the aileron (channel 2), elevator (channel 3) 

and rudder (channel 4). These channel defaults also 

correspond to the factory settings. ATTENTION: This 

assignment only applies if "2HRSv3+8" is not specifi ed 

in the line "Tail Unit" in the "Basic Settings" menu 

and "2AIL" or 2AIL 2FL" is not specifi ed in the line 

"Ail./Flap"! Otherwise the control function 3 (elevator)

which is already in the transmitter is split to the control 

channels 3 + 8 or the control function 2 (aileron) is split 

to the control channels 2 + 5 for left and right aileron. 

The corresponding control channels (INPUT CH) of the 

receiver in these two cases would be the channels 03 + 

08 or 02 + 05.

Therefore, if you have specifi ed "2AIL", for example, on 

the transmitter side and would like to utilize the option RX 

CURVE to be addressed here instead of the individually 

adjustable menu "Dual Rate / Expo", page 108, of the 

transmitter mx-20 HoTT, two curves must be set:
216 Detail program description - Control adjust

RX CURVE

 TYPE : A

CURVE1 CH : 02

 TYPE : A

CURVE2 CH : 05

 TYPE : B

CURVE3 CH : 04

Otherwise, the left and right ailerons have different 

control characteristics.

With the RX CURVE function you can manage the 

control characteristics for up to three servos:

• CURVE 1, 2 or 3 CH

Select the desired control channel (INPUT CH) of the 

fi rst servo.

The following setting in TYPE only pertains to the 

channel selected here.

TYPE

Select the servo curve:

A: EXPO = -100 % and DUAL RATE = 125 % 

The servo reacts strongly to movements of the 

joystick around the neutral position. As the rudder 

throw increases, the curve becomes fl atter.

B: Linear setting. 

The servo follows the joystick movement linearly.

C: EXPO = +100 % and DUAL RATE = 70 %

The servo reacts weakly to the joystick movements 

around the neutral position. As the rudder throw 

increases, the curve becomes steeper.

Notice:

The control characteristics programmed here also affect 

the mapped receiver outputs.

 RX SERVO TEST

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

TEST : STOP

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

CH OUT TYPE:ONCE

Value Explanation Possible settings

ALL-MAX Servo travel on 

the "+" side for all 

servo outputs for 

the servo test

1500 ... 2000 μs

ALL-MIN Servo travel on the 

"-" side for all servo 

outputs for the 

servo test

1500 ... 1000 μs

TEST Test procedure START / STOP

ALARM VOLT Alarm threshold 

of the receiver 

undervoltage 

warning

3,0 ... 6,0 V

factory setting: 

3.8 V 

ALARM 

TEMP+

Alarm threshold for 

excessively high 

temperature of the 

receiver

50 ... 80 °C

Factory setting: 

70 °C

ALARM 

TEMP–

Alarm threshold 

for excessively low 

temperature of the 

receiver

-20 ... +10 °C

Factory setting: 

-10 °C

CH OUTPUT 

TYPE

Channel sequence ONCE, SAME, 

SUMI, SUMO

ALL-MAX (servo travel on the "+" side)

In this line you set the maximum servo travel on the plus 

side of the control travel for the servo test.

2000 μs corresponds to the full throw; 1500 μs 

corresponds to the neutral position.

Make sure that the servos do not overrun mechanically 

during the test routine.

ALL-MIN (servo travel on the "-" side)

You adjust the maximum servo travel on the minus side 

of the control path for the servo test in this line.

1000 μs corresponds to the full throw; 1500 μs 

corresponds to the neutral position.

TEST

You start and stop the servo test integrated in the 

receivers in this line.

By pressing the central SET key of the right touch pad, 

you activate the input fi eld:

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

CH OUT TYPE:ONCE

TEST : STOP

With one of the arrow keys of the right touch pad, you 

now select START:

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

CH OUT TYPE:ONCE

TEST : START
Detail program description - Control adjust 217

By pressing the central SET key of the right touch pad, 

you now start the test run. The input fi eld is shown as 

"normal" again:

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

CH OUT TYPE:ONCE

TEST : START

To stop the servo test, reactivate the input fi eld as 

described above, select STOP and confi rm this selection 

with the SET key of the right touch pad.

 ALARM VOLT (receiver undervoltage warning)

The receiver voltage is monitored through ALARM 

VOLT. The interval can be adjusted between 3.0 

and 6.0 Volt. If the set alarm threshold is undercut, 

an acoustic signal is issued (interval peep tone long/

short) and "VOLT.E" blinks in the top right of all "RX ..." 

displays:

RX SERVO

REVERSE : OFF

CENTER : 1500μsec

TRIM : –000μsec

TRAVEL– : 150%

OUTPUT CH: 01

TRAVEL+ : 150%

PERIOD : 20msec

VOLT.E

The parameter "R-VOLT" is also represented inversely 

in the "RX DATAVIEW" display:

S–STR100% R–TEM.+28°C

L PACK TIME 00010msec

L.R-VOLT:03.5V

S–QUA100%S–dBM–030dBM

SENSOR1 :00.0V 00°C

SENSOR2 :00.0V 00°C

R-VOLT :03.7V

RX DATAVIEW VOLT.E

ALARM TEMP +/- (recommended temperature 

monitoring)

These two options monitor the receiver temperature. A 

lower threshold "ALARM TEMP-" (-20 ... +10 °C) and an 

upper threshold "ALARM TEMP+" (50 ... 80 °C) can be 

programmed. When these specifi cations are exceeded 

or undercut, an acoustic signal (continuous peep tone) 

sounds and "TEMP.E" appears in the top right of all 

receiver displays. In addition, the parameter "R-TEM" is 

shown inversely on the " RX DATAVIEW" display page.

Make sure that your receiver remains within the 

permissible temperature range during all fl ight 

conditions (ideally between -10 and 55 °C).

CH OUTPUT TYPE (connection type)

Here you select how the receiver outputs are controlled.

• ONCE

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

TEST : START

CH OUT TYPE:ONCE

The servo connections of the receiver are controlled 

successively. This is recommended for analog servos. 

With this setting the servos are automatically 

operated in a cycle of 20 ms – with a 12-channel 

receiver (Order No. 33512) 30 ms – regardless of 

what is set or displayed in the "PERIOD" line in the 

"RX SERVO" display!

• SAME

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

TEST : START

CH OUT TYPE:SAME

The servo connections of the receiver are controlled 

in parallel in blocks of four. That means the channels 

1 to 4, 5 to 8 and 9 to 12 each receive the control 

signals simultaneously.

This is recommended for digital servos when multiple 

servos are used for one function (e.g. aileron), so 

that the servos can run absolutely synchronized.

When only using digital servos, we recommend 

setting the "PERIOD" line of the "RX SERVO" to 10 

ms in order to be able to utilize the fast reaction of 

digital servos. With the use of analog servos or in 

mixer mode, "20 ms" must be selected!

With this setting, pay particular attention to the 

suffi cient dimensioning of the receiver current 

supply. Since up to four servos can always operate 

simultaneously, the requirement is higher.

• SUMO (sum signal OUT)
218 Detail program description - Control adjust

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

TEST : START

CH OUTPUT TYPE:SUMO

A HoTT receiver confi gured as SUMO permanently 

generates a so-called sum signal from the control 

signals of all of its control channels and provides this 

by default to the accompanying GR-24 receiver at 

servo connection 8.

On receivers whose display shows "SUMO" at the 

top right, an additional two-digit number appears ...

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

TEST : START

CH OUT TYPE:SUMO 08

... the active fi eld changes after confi rmation of 

"SUMO" by briefl y pressing the central SET key 

of the right touch pad for the channel selection. 

With this selection you specify the highest of the 

transmitter channels contained in the SUMO signal:

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

TEST : START

CH OUT TYPE:SUMO 08

You can confi rm the default by pressing the SET key 

of the right touch pad again or by selecting one of 

the other channels between 04 and 06 with the arrow 

keys and confi rming with SET. 

The receiver outputs are controlled successively in a 

cycle of 20 ms (30 ms with the receiver GR-24, Order 

No. 33512,), even if 10 ms is set in the "PERIOD" line 

of the the "RX SERVO" display page.

Primarily intended for the "Satellite mode" of two 

HoTT receivers, as described in the following, the 

generated sum signal defi ned by the receiver as 

SUMO can be used for the control of fl ight simulators; 

this is also the case for the control of fl yable systems, 

insofar as they have the corresponding input or the 

adapter cable with Order No. 33310.

In ...

 Satellite mode 

... two HoTT receivers are connected to one another 

through a three-wire connecting cable (Order No. 

33700.1 (300 mm) or 33700.2 (100 mm)) at receivertype-specifi c servo connections. Receivers of the 

type GR-16 and GR-24, for example, are to be 

connected with one another at servo output 8. More 

detailed information can be found on the internet at 

www.graupner.de.

Through this connection, all channels of the HoTT 

receiver which was confi gured as SUMO and 

identifi ed as a satellite receiver are transmitted to the 

second HoTT receiver, the main receiver, which is to 

be programmed as ...

• SUMI (sum signal IN)

 Therefore, the signal always goes toward SUMI:

RX SERVO TEST

ALL–MIN : 1000μsec

ALL–MAX : 2000μsec

ALARM VOLT : 3.8V

ALARM TEMP–:–10°C

ALARM TEMP+: 70°C

TEST : START

CH OUT TYPE:SUMI

The receiver defi ned as SUMI, however, only uses 

the sum signal coming from SUMO in the event of 

a failure of receipt if at least one channel in SUMI is 

programmed to fail-safe. 

If the receiver programmed as SUMO satellite 

receiver has a failure of receipt, the servos connected 

to this receiver assume the fail-safe positions 

programmed in the satellite receiver completely 

independently of the main receiver.

On the other hand, if a failure of receipt takes place 

with two receivers simultaneously, the receiver 

software current at the time of the printing of 

this manual falls back on the fail-safe settings of 

SUMO. In the individual case, however, interactions 

cannot be ruled out, which is why we urgently 

recommend performing an appropriate test 

BEFORE commissioning a model.

This receiver combination is recommended, if, for 

example , one of the two receivers is installed in 

the model at an unfavorable position for receiving 

or as a result of nozzles, carbon fi ber material or 

the like, there is the danger that the receipt signal 

is weakened due to the fl ight position, so that 

interruptions of the range must be taken into account.

Therefore, make sure to connect the most important 

control functions to the main receiver programmed 

as SUMI, so that, in the event of a failure, the model 
Detail program description - Control adjust 219

remains controllable when the SUMO satellite 

receiver no longer receives a signal.

Telemetry data, such as the voltage of the onboard 

electricity supply, on the other hand, is only sent to 

the transmitter by the satellite receiver confi gured 

as SUMO. Therefore, telemetry sensors are to be 

connected to the satellite receiver (SUMO).

Each receiver should be connected with its own 

supply line from the common voltage supply. With 

receivers with a high current load, it may even be 

benefi cial to connect them with two supply lines to 

the same current supply. 

On the other hand, if each of the two receivers 

should be supplied from 

its own voltage source, 

the center cable must 

be removed from one of 

the two plugs of the satellite cable; see fi gure.

red

1

2 3

If you would like to carry out additional programming, 

such as fail-safe settings, disconnect the threepole satellite connection between the two receivers 

and switch on only the relevant receiver. It may be 

necessary to also change the connection sequence.
220 Detail program description - Control adjust

 SENSOR SELECT

After selection of the desired menu line with the arrow 

keys  of the left or right touch pad...

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV rcv ch1

... and then pressing the central SET key of the right 

touch pad, the selected submenu opens:

 SENSOR SELECT

RECEIVER

GENERAL MODULE

VARIO MODUL

ELECTRIC AIR.MOD

GPS

Here, after selection of the desired line with the arrow 

keys  of the left of right touch pad and then 

pressing the central SET key of the right touch pad, 

activate ( ) or deactivate ( )the data output of the 

sensor connected to a receiver with active telemetry 

connection. It is only possible to select one sensor, e. g.:

 SENSOR SELECT

RECEIVER

GENERAL MODULE

VARIO MODUL

ELECTRIC AIR.MOD

GPS

This selection is required to show the sensor in the "VOICE 

TRIGGER" submenu and for the display of the telemetry 

data in the corresponding graphic displays, page 32.
Detail program description - Control adjust 221

After selection of the desired menu line with the arrow 

keys  of the left or right touch pad ...

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV rcv ch1

... and then pressing the central SET key of the right 

touch pad, the selected submenu opens. This provides 

a visualization of the quality of the connection of 

transmitter and receiver:

R100%

SD 40

E 10

RD 51

4.8VC

S 90%

4.8VM 0123456789ABCDE

Top row: Reception power of the channels 1 ... 

75 of the 2.4 GHz band in dBm coming 

from the receiver to the transmitter.

Bottom row: Reception power of the channels 1 ... 

75 of the 2.4 GHz band in dBm coming 

from the transmitter to the receiver.

Comments:

• Since the reception power is measured and 

represented in dBm, the reception power is 

increasingly worse the higher the bar is and vice 

versa; for this purpose, see also "Reception power 

(S-dBm)" on page 224. 

• Mark the points above the columns with the poorest 

 RF STATUS VIEW

reception power since switching on the transmitter 

or the resetting of the display by simultaneously 

pressing the keys  or  of the right touch pad 

(CLEAR).

Additional fi gures are shown to the left of the graphic 

representation of the reception power. These mean:

Value Explanation

E Signal quality in % of the signal 

received from the receiver

S Signal quality in % of the signal 

received by the receiver

SL Reception power in dBm

P Number of lost data packages of the 

receiver

RL Reception power in dBM of the signal 

received by the receiver

RS Current operating voltage of the 

receiver in volts

RM Lowest receiver operating voltage 

since last startup, in volts
222 Detail program description - Control adjust

After selection of the desired menu line with the arrow 

keys  of the left or right touch pad ...

TELEMETRY

SETTING & DATA VIEW

SENSOR SELECT

RF STATUS VIEW

VOICE TRIGGER

TEL.RCV rcv ch1

... and then pressing the central SET key of the right 

touch pad, the selected submenu opens:

 REPEAT

VOICE TRIGGER

REPEAT 1SEC

TRIG

TRANSFER

RECEIVER

–––

–––

VARIO –––

In order to be able to start the voice output through the 

headphone connection, at the very least the "REPEAT" 

line must be assigned to a switch. The takes place as 

described in the section "Switch and control switch 

assignments" on page 52:

VOICE TRIGGER

REPEAT 1SEC

TRIG

TRANSFER

RECEIVER

–––

–––

VARIO –––

Move desired switch

to ON position

 VOICE TRIGGER

–––

3

–––

VOICE TRIGGER

REPEAT 5SEC

TRIG

TRANSFER

RECEIVER

VARIO

With this switch you can have the last respective voice 

trigger repeated for the duration of the time set to the left 

of the switch, as long as the assigned switch is closed:

 TRIG

With a switch assigned to this line, preferably one of 

the two pushbuttons SW 1 or SW 9, switch to the next 

voice output in the rotation selected in the options 

"TRANSMITTER", "RECEIVER" and "SENSOR" as 

described in the following. 

1

3

–––

VOICE TRIGGER

REPEAT 5SEC

TRIG

TRANSFER

RECEIVER

VARIO

 VARIO

If you activate the "VARIO MODULE" line( ) in the 

"SENSOR SELECT" submenu, described on page 220, 

you can use the headphone connection to activate a 

switch assigned to this line completely independently 

of the other voice triggers, in other words voice triggers 

triggered by changes in altitude, such as "Slow climb/

descent", etc.

1

3

8

SENSOR

VOICE TRIGGER

REPEAT 5SEC

TRIG

TRANSFER

RECEIVER

VARIO

 TRANSMITTER

After selection of the desired menu line with the arrow 

keys  of the left or right touch pad...

1

3

8

SENSOR

VOICE TRIGGER

REPEAT 5SEC

TRIG

TRANSFER

RECEIVER

VARIO

... and then pressing the central SET key of the right 

touch pad, the selected submenu opens:

TX VOLT:

MODEL TIME:

BATTERIETIME:

TIMER(GE:)CENTER:

TIMER(GE.)TOP:

TIME:

Here, after selection of the desired line with the arrow 

keys  of the left or right touch pad and then 

pressing the central SET key of the right touch pad, 

activate ( ) or deactivate ( ) the data output of the 

selected voice trigger:
Detail program description - Control adjust 223

TX VOLT:

MODEL TIME:

BATTERIETIME:

TIMER(GE:)CENTER:

TIMER(GE.)TOP:

TIME:

 RECEIVER

After selection of the desired menu line with the arrow 

keys  of the left or right touch pad ...

1

3

8

SENSOR

VOICE TRIGGER

REPEAT 5SEC

TRIG

TRANSFER

RECEIVER

VARIO

... and then pressing the central SET key of the right 

touch pad, the selected submenu opens:

TEMP:

STRENGHT:

RX VOLT:

LOWVOLT:

Here, after selection of the desired line with the arrow 

keys  of the left or right touch pad and then 

pressing the central SET key of the right touch pad, 

activate ( ) or deactivate ( ) the selected voice 

trigger.

 SENSOR

This line only appears if a sensor was fi rst activated in 

the "SENSOR SELECT" submenu:

1

3

SENSOR

8

VOICE TRIGGER

REPEAT 5SEC

TRIG

TRANSFER

RECEIVER

VARIO

If, for example, the "VARIO" sensor was selected, after 

selection of the "SENSOR" line and then pressing the 

central SET key of the right touch pad, the following 

display appears:

ALTITUDE:

MAXALT:

MINALT:

VOLT MINIMUM:

As described in the left column, you can also activate 

( ) or deactivate ( ) the voice trigger of the desired 

line after pressing the central SET key of the right touch 

pad.

Notice:

The selection made here is completely independent of 

the "VARIO" voice triggers.
224 Detail program description - Control adjust

Using the arrow keys of the left or right touch pad, scroll 

to the "Basic Settings" menu item of the multifunction 

menu: 

Telemetry

info display

Basic settings

Servo display

Servo test

Code lock

By briefl y pressing the central SET key of the right touch 

pad, this menu item opens:

Batterie type

Batterie warning

Touch Sense

Contrast

Ni-MH

Display light

Region

Voice volume

2

4.7V

0

Euro

3

unlim.

Beep volume 3

BASIC SETTINGS

Own

Stick mode 1

DSC Output PPM10

Pitch min back

Power-on beep yes

Power on warn. unlim

General basic settings are entered in this menu ... 

specifi c to the transmitter, such as the owner's name 

and defaults for new model memories.

The settings saved in this menu in the lines ...

• "Stick mode",

• "DSC Output",

• "Pitch min"

... have no infl uence whatsoever on already existing 

model memories; they are only defaults, which are 

automatically adopted to newly initialized model 

memories and can be changed there on an individually 

basis at any time in the "Basic model settings" 

and "Helicopter type" menus. A change to the 

"specifi cations" in this menu, therefore, only infl uences 

model memories created at a later time.

Notice:

Settings in this menu are only assigned once for 

transmitters. After opening this menu in another model 

memory, therefore, the last valid settings always appear.

Select the appropriate line with the arrow keys  of 

the left or right touch pad and then press the central 

SET key of the right touch pad. In the inverse value fi eld 

you can now change the respective specifi ed value with 

the arrow keys of the right touch pad and complete your 

entry by pressing the central SET key of the right touch 

pad or the ESC key of the left touch pad.

Own(er)

H.J.Sandbrunner

1

PPM10

BASIC SETTINGS

Own

Stick mode

DSC Output

Pitch min back

Up to 15 characters can be used to specify the owner's 

name. Change to the next screen page ( ) by 

pressing the SET key of the right touch pad:

 !"#$%&’()+,–./012

3456789:;

Owner H-J Sandb

FGHIJKLMNOPQRSTUVWX

YZ[¥]^_`a b cdefghijk

?@ABCDE

Select the desired characters with the arrow keys of 

the left touch pad. Switch to the next position by briefl y 

pressing the arrow key  of the right touch pad of the 

SET key to be able to select the next character. A blank 

space can be entered by simultaneously pressing the 

keys  or  of the right touch pad (CLEAR).

You can reach any arbitrary character position within the 

input fi eld with the  keys of the right touch pad.

You return to the previous menu page by briefl y pressing 

the central ESC key of the left touch pad.

 Stick mode (specifi cation)

As a basic principle, there are four different ways to 

assign the four control functions, aileron, elevator, 

rudder and throttle or brake fl aps for winged models as 

well as rolling, pitching, tail rotor and throttle/pitch for 

helicopter models to the two joysticks. The model pilot 

determines which way to do so according to individual 

preferences.

With the arrow keys  of the left or right touch pad, 

select the "Stick mode" line. The selection fi eld is shown 

in a box:

 General settings

Basic transmitter settings
Detail program description - Control adjust 225

H-J Sandbrunner

1

PPM10

SEL

BASIC SETTINGS

Own

Stick mode

DSC Output

Pitch min back

Briefl y press the SET key. The current stick mode is 

shown inversely. Now, using the arrow keys of the 

right touch pad, select the alternative you use most 

frequently, from 1 to 4. In the future this will be used for 

newly initialized model memories, but can be changed 

on an individual basis for up to 24 model memories.

After simultaneously pressing the keys  or  of 

the right touch pad (CLEAR), the display returns to stick 

mode "1"

By pressing the SET key again, you deactivate the 

selection fi eld in order to switch lines.

Winged model stick mode

“MODE 2” (Throttle at left stick)

“MODE 3” (Throttle at right stick) “MODE 4” (Throttle at left stick)

“MODE 1” (Throttle at right stick)

elev. down

elev. up

left rudder

right rudder

full throttle

idle

left aileron

right aileron

full throttle

left rudder

right rudder

idle

elev. down

elev. up

left aileron

right aileron

elev. down

elev. up

left aileron

right aileron

Motor Vollgas

idle

left rudder

right rudder

full throttle

idle

left aileron

right aileron

elev. down

elev. up

left rudder

right rudder

Helicopter model stick mode

“MODE 2” (Throttle at left stick)

“MODE 3” (Throttle at right stick) “MODE 4” (Throttle at left stick)

“MODE 1” (Throttle at right stick)

pitch axis

tail rotor

pitch axis

tail rotor

throttle

roll

roll

throttle

tail rotor

tail rotor

throttle throttle

pitch axis

pitch axis

roll

roll

pitch axis

pitch axis

roll

roll

Motor/Pitch

throttle

tail rotor

tail rotor

throttle

throttle

roll

roll

pitch axis

pitch axis

tail rotor

tail rotor

 DSC Output (specifi cation)

In the line with the same name in the "Base setup 

model" menu you can determine which of the three 

available modulation types should be provided for the 

DSC socket separately for each model memory. This 

selection primarily infl uences the number of maximum 

control channels available at the DSC socket and 

thus for a fl ight simulator or LS system connected at 

this socket. With the selection of "PPM10", this is the 

channels 1 ... 5, with "PPM18" the channels 1 ... 9 and 

with "PPM24" the control channels 1 ... 12.

SEL

99sec

DSC output PPM10

RF Range Test

R12 R08

OFF

BASIC SETTINGS, MODEL

Rcv Ch Map

RF transmit

In this "General settings" menu, you can determine 

which of the three possible "Modulation types" should 

be adopted as the default to a newly initialized model 

memory in the line "DSC Output" the same way as with 

"Stick mode".

If necessary, using the arrow keys  of the left or 

right touch pad, switch to the "DSC Output" line and, by 

briefl y pressing the central SET key of the right touch 

pad, activate the value window:

H-J Sandbrunner

1

SEL

BASIC SETTINGS

Own

Stick mode

DSC Output

Pitch min back

PPM10

Now you case choose between the three possible 

modulation types "PPM10", "PPM18" and "PPM24" 

using the arrow keys of the right touch pad. By pressing 

the central SET key of the right touch pad again, you 

complete the entry.

Simultaneously pressing the keys  or  of the 

right touch pad (CLEAR) returns to "PPM10".

 (Default) Pitch min

(only relevant for helicopter models)

Enter your preferred actuation direction for the throttle/

pitch joystick analogously to the "Stick mode" and "DSC 

Output" options described above, in order to be able 

to fi nd it for newly initialized model memories in the 

future. The functions of all other options of the helicopter 

program depend on this setting, insofar as they pertain to 

the throttle and pitch function, in other words the throttle 

curve, idle trim, Channel 1  tail rotor mixer, etc.

The following meanings apply:

"front": minimum front pitch setting, the pitch joystick 

(C1) points away from the pilot.
226 Detail program description - Control adjust

"rear": minimum rear pitch setting, the pitch joystick 

(C1) points towards the pilot.

Simultaneously pressing the keys  or  of the 

right touch pad (CLEAR) switches to "rear"

Notice:

The stick mode of the C1 joystick in the winged model 

program for "Throttle min front/rear" can be individual 

changed in the "Model type" menu.

 Contrast

In order to guarantee the optimal visibility of the display 

of the mx-20 HoTT in any weather and at any 

temperature, you can adjust its contrast: 

GRAUBELE

#01

2:22h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

GRAUBELE

#01

2:22h

Stop

Flt

«normal »

K78

0:00

0:00

5.5V

5.2V

M

HoTT

For this purpose, using the arrow keys of the left or 

right touch pad, select the "Contrast" line:

1

SEL

PPM10

Contrast 0

BASIC SETTINGS

Stick mode

DSC Output

Pitch min back

Then briefl y press the central SET key of the right touch 

pad. Now you can adjust the display contract in a range 

of ±20 using the arrow keys of the right touch pad in the 

inverse value fi eld.

Simultaneously pressing the arrow keys  or 

of the right touch pad (CLEAR) resets the inverse fi eld 

to "0". 

 Display light

In this line you can determine how long the backlight of 

the display should remain switched on after switching on 

the transmitter or the last key actuation.

The available options are "unlim(ited), "30 s", "60 s" and 

"120 s".

Simultaneously pressing the arrow keys  or 

of the right touch pad (CLEAR) sets the inverse fi eld to 

"unlimited".

 Power-on beep

In this line you can switch the power-on beep of the 

transmitter on ("yes") and off ("no").

Simultaneously pressing the arrow keys  or 

of the right touch pad (CLEAR) switch the inverse fi eld 

back to "yes".

 Battery type

SEL

0

Battery type Ni-MH

Contrast

Display light unlim.

BASIC SETTINGS

Power-on beep yes

In this line you indicate to the transmitter whether its 

power supply is provided from a four-cell NiMH battery 

or a single-cell LiPo battery. Depending on this setting, 

you are offered a suitable voltage range in the (next) line 

"Battery warning".

Simultaneously pressing the arrow keys  or  of 

the right touch pad (CLEAR) switches back to "Ni-MH" 

in the inverse fi eld.

 Battery warning threshold

SEL

Ni-MH

4.7V

Battery type

Battery warning

Display light unlim.

BASIC SETTINGS

Power-on beep yes

You can arbitrarily specify the warning threshold for the 

display ...

battery

needs

charging

... – depending on the selection of the battery type in 

the line above it – in increments of 0.1 volt between 4.5 

and 5.5 V (NimH battery) or 3.4 and 4.2 V (LiPo battery. 
Detail program description - Control adjust 227

Make sure that you do not enter a value which is too 

low, so that you still have suffi cient time to safely land 

your model in the event of a battery warning.

Simultaneously pressing the arrow keys  or 

of the right touch pad (CLEAR) switches back to the 

factory default values 4.7 or 3.4 V in the inverse fi eld.

 Power-on warning

SEL

Ni-MH

4.7V

Batterie type

Batterie warning

BASIC SETTINGS

Power-on beep yes

Power on warn. unlim

In this line you can determine how long the transmitter 

should wait after the last actuation of an operating 

element until the activation of an optical and acoustic 

power-on warning before the transmitter switches off 

automatically one minute later.

The values "unlim(ited)", "30 s" and 1, 5, 10, 20, 30 and 

60 minutes are optional selections.

Simultaneously pressing the arrow keys  or  of 

the right touch pad (CLEAR) switches to "unlimited" in 

the inverse fi eld.

Notice:

In order to be able to restart the transmitter after 

automatic shut-off, slide the power switch of the 

transmitter fi rst towards the display, to the "OFF" position 

and, after approx. fi ve seconds, back towards the 

antenna to the "ON" position.

 Touch sensitivity

SEL

Ni-MH

4.7V

2

Batterie type

Batterie warning

Touch Sense

BASIC SETTINGS

Power on warn. unlim

In this line you can select the touch sensitivity of the 

touch pads in a range from 1 to 10.

Simultaneously pressing the arrow keys  or  of 

the right touch pad (CLEAR) resets to "2" in the inverse 

fi eld.

 Region

SEL

4.7V

2

Euro

Batterie warning

Touch Sense

Region

BASIC SETTINGS

Power on warn. unlim

The region is needed for compliance with various 

regulations (FCC, ETSI, IC etc.). In France, for example, 

the operation of a remote control is only permitted within 

a limited frequency band. Therefore, the region setting of 

the transmitter MUST be switched to "France" mode 

as soon as it is operated in France. In no case may 

the Universal/EURO mode be used in France!

Simultaneously pressing the arrow keys  or 

of the right touch pad (CLEAR) resets to "Euro" in the 

inverse fi eld.

 Voice volume

SEL

2

Euro

3

Touch Sense

Region

Voice volume

BASIC SETTINGS

Power on warn. unlim

The volume of the voice output through the earpiece 

connection is defi ned in a range of "0" to "10" in this line.

Simultaneously pressing the arrow keys  or  of 

the right touch pad (CLEAR) resets to "3" in the inverse 

fi eld.

 Beep volume 

SEL

2

Euro

3

3

Touch Sense

Region

Voice volume

Beep volume

BASIC SETTINGS

The volume of the transmitter's internal beep generator 

is defi ned in a range from "0" to "6" in this line.

Simultaneously pressing the arrow keys  or  of 

the right touch pad (CLEAR) resets to "3" in the inverse 

fi eld.
228 Detail program description - Control adjust
Detail program description - Control adjust 229
230 Detail program description - Control adjust

 Servo display

Display of the servo position

Scroll to the menu item "Servo display" of the 

multifunction menu using the arrow keys of the left or 

right touch pad: 

Telemetry

info display

Basic settings

Servo display

Servo test

Code lock

By briefl y pressing the central SET key of the right touch 

pad, you open this menu item.

The visual display of the current servo positions, 

however, can be opened both by selecting this menu 

and by simultaneously pressing the keys  left touch 

pad directly from the base screen of the transmitter, as 

well as nearly all menu positions. By briefl y pressing the 

central ESC key of the left touch pad, you return to the 

respective starting point. 

1

3

5

7

+

0%

0%

9

11

0%

0%

2

4

6

8

+

0%

0%

0%

10 0%

12 0%

–100%

+100%

+100%

The current position of a servo is displayed in a bar 

diagram between -150 % and +150 % of the normal 

path, in consideration of the control and servo settings, 

the dual-rate/expo functions, the interplay of all active 

linear and curve mixers, etc. 0 % corresponds precisely 

to the servo center position. This way, you can quickly 

check your settings without having to switch on the 

receiver. However, this does not absolve you from fi rst 

carefully testing all program steps, as well as on the 

model, prior to the fi rst operation of the model in order to 

eliminate errors!

For winged models the display takes place 

according to the following scheme:

Bar 1 = Throttle/brake servo

Bar 2 = Aileron or left aileron

Bar 3 = Elevator

Bar 4 = Rudder

Bar 5 = Right aileron

Bar 6 = Camber-changing fl ap (left) / free channel

Bar 7 = Right camber-changing fl ap / free channel

Bar 8 = Free channel / second elevator servo

Bar 9 = Free channel / Left FL2

Bar 10 = Free channel / Right FL2

Bar 11 = Free channel

Bar 12 = Free channel

... and with helicopter models:

Bar 1 = Pitch or roll (2) or pitch (2) servo

Bar 2 = Roll (1) servo

Bar 3 = Pitch (1) servo

Bar 4 = Tail servo (gyro)

Bar 5 = Pitch (2) servo / free channel

Bar 6 = Throttle servo or speed controller

Bar 7 = Gyro sensitivity / free channel

Bar 8 = Speed regulator / free channel

Bar 9 = Free channel

Bar 10 = Free channel

Bar 11 = Free channel

Bar 12 = Free channel

Notice:

• However, please note that the servo display is only 

based on the original sequence of servos, so any 

switching of the outputs do not take place in either 

the "Transmitter output" menu or "Receiver output" 

menu.

• The number of channels shown in this menu 

correspond to the 12 control channels available in the 

mx-20 HoTT transmitter. The number of actually 

usable channels, however, depends on the receiver 

type as well as the number of servos connected to 

it and, therefore, may be considerably lower under 

certain circumstances.

• Use this display during the model programming, 

because you can immediately check all settings on 

the transmitter. However, this does not absolve you 

from fi rst carefully testing all program steps, as well 

as on the model, prior to the fi rst operation of the 

model in order to eliminate errors!
Detail program description - Control adjust 231

 Servo test

Function test of Servo 1 ... 8

Scroll with the arrow keys of the left or right touch pad to 

the menu item "Servo test" of the multifunction menu: 

Telemetry

info display

Basic settings

Servo display

Code lock

Servo test

By briefl y pressing the central SET key of the right touch 

pad, this menu item opens:

SERVO TEST

act

off

123 4 5 6 7 8

0.5s

Any of the inputs 1 ... 8 can be activated for the servo 

test by selecting with the arrow keys of the left or right 

touch pad and then briefl y pressing SET key of the right 

touch pad. As soon as you have set only one of the 

inputs 1 ... 8 to "active", the following notice appears at 

the bottom of the display screen:

123 4 5 6 7 8

CLR=act./deact. 0.5s

SERVO TEST

act

off

Simultaneously pressing the arrow keys  or  of 

the right touch pad (CLEAR) would now start and stop 

the servo test for input "1", fo r example, with a cycle 

time of 0.5 s.

To change the cycle time, select the time input fi eld 

with the arrow keys of the left or right touch pad. After 

activation of the input fi eld by briefl y pressing the central 

SET key of the right touch pad, the movement cycle 

can be changed in 0.5 s increments between 0.5 s and 

3.0 s using the arrow keys of the left or right touch pad. 

Briefl y pressing the central ESC of the left touch pad or 

the central SET key of the right touch pad completes the 

time presetting.

123 4 5 6 7 8

HLD = aktiviert 3.0s

SERVO TEST

act

off

The "servo test" function started by simultaneously 

pressing the arrow keys  or  of the right touch 

pad (CLEAR) automatically control all servos as though 

the would simultaneously and permanently move the 

corresponding control back and forth between -100 

% and +100 % in the set time. All active mixing and 

coupling functions in the respective model memory, 

therefore, are effective and the servos move within the 

specifi ed servo paths and servo delimitations.

As soon as you have started the servo test by 

simultaneously pressing the arrow keys  or  of 

the right touch pad (CLEAR), a window opens:

123 4 5 6 7 8

CLR=act./deact. 3.0s

Servo test act.

SERVO TEST

act

off

Simultaneously press the arrow keys  or  of 

the right touch pad (CLEAR) in order to end the test.

Important notice:

The shut-off of the transmitter does not 

automatically end an active servo test. Therefore, 

always stop a servo test manually BEFORE 

SHUTTING OFF the transmitter, because the servo 

test is otherwise restarted after switching on the 

transmitter again.
232 Detail program description - Control adjust

 Code lock

Locking of the multifunction list

Scroll with the arrow keys of the left or right touch pad to 

the menu item ...

Telemetry

info display

Basic settings

Servo display

Servo test

Code lock

... of the multifunction menu. By briefl y pressing the 

central SET key of the right touch pad, this menu item 

opens:

CODE LOCK

Desired (new)

secret number

(_ )

SET

1 2 3 4

Access to the multifunction menu can be locked for 

unauthorized use by a four-digit secret code comprised 

of the numbers 1 to 4, which you enter according to the 

scheme shown in the display with the arrow keys of the 

left touch pad; for example :

(123_)

CLR

1 2 3 4

CODE LOCK

Desired (new)

secret number

As soon as you not enter the fourth number by pressing 

one of the other arrow keys of the left touch pad, the 

following notice appears in the display:

789 10 11 12

STO

FAIL SAFE

Pos

hold

 DELAY : 0.25s

By briefl y pressing the central ESC key of the left touch 

pad, you confi rm the secret code and leave the menu.

By briefl y pressing the central SET key of the right touch 

pad, on the other hand, you confi rm the active CLR fi eld 

in the bottom right in the display and thereby delete the 

number you entered.

Make note of the secret code and keep it safe. 

Otherwise, the transmitter must be sent in to 

Graupner Service for decoding.

The lock becomes active the next time the transmitter 

is switched on. However, the control remains ready 

for operation. Calling the multifunction list and thereby 

a model change, for example, is no longer possible 

without entering the correct number combination:

(_ )

SET

1 2 3 4

CODE LOCK

Desired (new)

secret number

A renewed attempt following an incorrect entry is only 

possible after the lapse of a time-out.

(123_)

CLR

1 2 3 4

CODE LOCK

Desired (new)

Input error secret number

Time lock

Deletion of the secret code

If the secret code should be deleted again at a later 

point in time, after opening this menu, immediately press 

the central SET key of the right touch pad twice :

(1234)

CLR

1 2 3 4

CODE LOCK

Desired (new)

secret number

The fi rst time you press the central SET key of the right 

touch pad, the secret code is deleted (CLR):

1.234

2048MB

2011/02/01(Mo )

11:22:33s

1234MB

firmware ver.

date

time

SD-Card

available

And the second time you press the key the empty input 

fi eld is confi rmed (SET). The display shows:
Detail program description - Control adjust 233

(123_)

SET

1 2 3 4

CODE LOCK

Desired (new)

Memorise secret secret number

 none 

Now leave the menu by briefl y pressing the central ESC

key of the left touch pad.

 Leaving the menu without input of a secret code

You would like to leave the menu opened out of curiosity 

or by accident and have not pressed any other key. 

Therefore, the display appears as follows:

1.234

2048MB

2011/02/01(Mo )

11:22:33s

1234MB

firmware ver.

date

time

SD-Card

available

Press the central SET key of the right touch pad once. 

The following display appears:

(123_)

SET

1 2 3 4

CODE LOCK

Desired (new)

Memorise secret secret number

 none 

Now leave the menu by briefl y pressing the ESC key of 

the left touch pad.

Tip:

If you generally want to dispense with a programmer 

lock, you should, if applicable, remove this menu from 

the multifunction list with "Suppress menus" so that 

unauthorized persons cannot enter a secret code "on 

the sly".
234 Detail program description - Control adjust

 Info display

Transmitter ID, date, time and memory card

With the arrow keys of the left or right touch pad, scroll 

to the menu item ... 

Telemetry

Basic settings

Servo display

Servo test

Code lock

info display

... of the multifunction menu. Briefl y pressing the central 

SET key of the right touch pad opens this menu:

RFID

firmware ver.

date

time

SD-Card

available

1.234

0MB

0%

ABCDEF12

2011/08/01(Mo )

11:22:33s

0MB

Transmitter-specifi c information is shown in this menu 

and – insofar as necessary and benefi cial – also 

changed.

Select the appropriate line with the arrow keys 

of the left or right touch pad and then briefl y press the 

central SET key of the right touch pad. In the inverse 

value fi eld you can now change the respective default 

value – insofar as possible and necessary – with the 

arrow keys of the right touch pad and complete your 

entry by pressing the central SET key again.

 RFID

1.234

0MB

ABCDEF12

2011/08/01(Mo )

11:22:33s

RFID

firmware ver.

date

time

SD-Card

The RF identifi cation number of the transmitter is shown 

in this line. It is transmitter-specifi c, is only issued once 

per transmitter and cannot be changed. During the 

connection process, this is sent to the receiver, among 

other things, so that it is always capable of identifying 

the radio signals of "its" transmitter.

 Firmware Version

1.234

0MB

ABCDEF12

2011/08/01(Mo )

11:22:33s

RFID

firmware ver.

date

time

SD-Card

The current version number of the transmitter software 

is shown in this line. 

Through a comparison of the number shown here with 

the update version offered on the internet download 

page of the corresponding product under www.graupner.

de, you can determine whether a current update of the 

transmitter operating system is available.

If applicable, the version number is also required for 

inquiries with the service department.

 Date

1.234

0MB

ABCDEF12

2011/08/01(Mo )

11:22:33s

RFID

firmware ver.

date

time

SD-Card

If necessary, select this line with the arrow keys of the 

left or right touch pad and, if applicable, the month or 

date fi eld. After activation of the respective value fi eld 

by pressing the central SET key of the right touch pad, 

the year, month or date can be set with the arrow keys 

of the right touch pad. Pressing the central SET key of 

the right touch pad again completes the respective entry. 

Years ranging from 2000 to 2135 are available.

The abbreviated day of the week to the right outside in 

brackets is automatically generated from the respective 

date.

Notice:

• If the transmitter is connected to a PC as described 

on page 39, the date and time can also be set 

through the PC program provided for the respective 

product on the internet page at www.graupner.de.

• The date and time are protected against data loss 

due to power failure by a buffer battery for situations 

like a battery change, see page 15. 
Detail program description - Control adjust 235

 Time

1.234

0MB

ABCDEF12

2011/08/01(Mo )

11:22:33s

RFID

firmware ver.

date

time

SD-Card

If necessary, select this line with the arrow keys of the 

left or right touch pad and the minute fi eld, if applicable. 

After activation of the respective value fi eld by pressing 

the central SET key of the right touch pad, the hour or 

minute can be adjusted with the arrow keys of the right 

touch pad. Pressing the central SET key of the right 

touch pad again completes the respective entry. 

Contrary to this, the seconds display cannot be directly 

adjusted; it can only be restarted by briefl y pressing the 

central SET key of the right touch pad with "00".

Notice:

• If the transmitter is connected to a PC as described 

on page 39, the date and time can also be set 

through the PC program provided for the respective 

product on the internet page at www.graupner.de.

• The date and time are protected against data loss 

due to power failure by a buffer battery for situations 

like a battery change, see page 15. 

 SD card

1.234

2048MB

ABCDEF12

2011/08/01(Mo )

11:22:33s

RFID

firmware ver.

date

time

SD-Card

In this line the memory capacity of a memory card 

inserted in the transmitter, if applicable, is shown in MB.

Depending on the memory capacity of the inserted 

micro SD or micro SDHC memory card, it may take 

several minutes until the correct value is shown after 

switching on the transmitter.

 available

1.234

2048MB

2011/02/01(Mo )

11:22:33s

1234MB

firmware ver.

date

time

SD-Card

available

Display of the available storage space in MB.

As mentioned before, the display of the available 

storage space – depending on the capacity of the 

inserted memory card – does not appear until some time 

has passed after switching on the display.

The display of the available storage space in relation to 

the total memory capacity is shown in the line below:

2048MB

2011/08/01(Mo )

11:22:33s

1234MB

60%

date

time

SD-Card

available

As mentioned before, the display of the available storage 

space – depending on the capacity of the inserted 

memory card – does not appear until some time has 

passed after switching on the display.
236 Detail program description - Control adjust

mx-20 HoTT programming

 Preparatory measures based on the example of a winged model

Programming models in an mx-20 HoTT ...

... is easier than it may appear at fi rst!

The basic requirement for "clean" programming, 

however, and this applies not only to the mx-20 

HoTT, but basically to all programmable transmitters, 

is the mechanically correct installation of all remote 

control components in the model! Therefore, it should 

be ensured no later than on connection of the linkages 

that the servos are in their respective neutral position 

and their rudder lever is also in the desired position. 

Otherwise you should loosen the rudder and re-fasten 

it with an offset of a few lobes. If, in the process, the 

servos are moved into position using a servo tester, 

such as the RC-Tester with Order No. 2894.12, the 

"correct" position can be determined very easily. 

The possibility of changing the neutral position of a 

servo in practically every modern transmitter is only 

intended for the fi ne-tuning. Greater deviations from 

"0" can result to further asymmetries in the course of 

the further signal processing in the transmitter. In the 

same manner: A car with a bent chassis does not get 

any straighter if only the steering wheel is trimmed to 

"straight"!

An additional important point is the adjustment of 

the rudder paths: This should take place through 

a corresponding adjustment of the steering points, 

insofar as possible. Ultimately this is far more effi cient 

than extensive efforts with the path adjustments in the 

transmitter! In this case: Path adjustments serve fi rst 

and foremost for to compensate for the manufacturerstipulated tolerances for the servos and their fi ne-tuning, 

and less for the compensation of carelessness.

If two separate aileron servos are used for a 

winged model, the ailerons, controlled through the 

corresponding activated wing mixer – see the following 

pages – can be assigned with both the fl ap function and 

raised with the brake fl aps – however this would make 

more sense in a glider or electro glider than in a motor 

model.

In this case the rudder arms – starting from the neutral 

position – should be tilted forward one lobe, pointing 

toward the nose, set to the respective servo. 

The mechanical differentiation achieved through this 

asymmetric assembly contributes to the fact that the 

brake effect of the elevated ailerons increases with their 

defl ection and, therefore, does not normally require a 

greater path upward than downward.

Correspondingly, when planning to operated separately 

controlled fl ap servos, they should also be integrated 

into a crow system. Since the brake effect of this fl ap 

position referred to as a "crow position" is infl uenced 

less by the elevated ailerons than the downward 

defl ection of the fl aps, the rudder arms should be 

installed somewhat toward the rear in this case, tilted 

toward the trailing edge. As a result, there is a greater 

available path for the downward defl ection. With such 

a combination of lowered fl aps with raised ailerons, 

however, the latter should only be elevated moderately, 

because they have more of a stabilizing and controlling 

function than a braking function in this type of crow 

system.

A "tip" for seeing the brake effect in this connection: 

Spread the fl aps and look above and below the surface 

from the front. The greater the projected surface of the 

protruding rudder, the greater the brake effect.

Outboard ailerons

Inboard camber-changing flaps

(Eine ähnlich asymmetrische Montage der Ruderarme 

kann z. B. an Spreiz- bzw. Landeklappen auch in einem 

Motormodell sinnvoll sein.)

If a model is completed and mechanically attuned in this 

respect, you can basically begin with the programming 

of the transmitter. The following examples, an attempt is 

made to follow the practice of fi rst describing the general 

basic settings and then fi ne-tuning or specializing them 

in the subsequent steps. After the initial fl ight and over 

the course of the further fl ying in of a model, it may be 

necessary to occasionally adjust some of the settings. As 

a pilot's experience increases, however, so does the desire 

for enhancements and expansions of settings. For this 

reason, the sequence of options is not always adhered to 

or some options are even mentioned multiple times.

Of course, just the opposite can also be the case, 

that not everyone of the described steps is relevant 

for a certain model, just as some users may miss the 

description of a certain step for their model ...
Detail program description - Control adjust 237

whatever the case may be, you should consider a logical 

assignment of the control mechanisms before you begin 

with the model programming.

For models in which the emphasis is on the "motor", 

regardless of whether it is powered by an electric 

or combustion motor, there should be no problem 

in this respect, because the assignment of the two 

joystick units essentially lies in the four basic functions 

"Power regulation (= throttle)", "Side", "Altitude" and 

"Transverse"! However, in the menu ...

"Model type" (beginning 82)

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1 +100%

SEL

... you should determine whether you would like 

the minimum throttle position in the "front" or "rear", 

because "none (motor)" is entered by the program in the 

creation of a model memory as a basic principle.

The difference between "no" and "idle front/rear" is 

not only in the effect of the C1 trimming, which is over 

the entire joystick path with "none" and with "idle front/

rear" only effects the idle direction. In the process, 

the "effective direction" of the C1 joystick is adapted 

accordingly, so that with a change from "front" to "rear" 

or vice versa, the rotational direction of the throttle servo 

or brake system do not have to be adapted as well. 

In addition, with an "idle front/rear" setting, a warning 

indication appears in the display for safety reasons and 

issues a warning beep, if the throttle joystick is too far in 

the full-throttle direction:

GRAUBELE

#01

2:22h

Stop

Flug

K78

0:00

0:00

0.0V

5.2V50%

M

HoTT

Throttle

too

high!

In any case, you will also have to consider "special 

functions". 

With electro gliders, on the other hand, it is only 

occasionally different. In this regard, one must ask 

how the drive and brake system are actuated. Certain 

solutions have shown to be practical and others have 

shown to be less practical.

For example, it is certainly less practical, if you have to 

release a joystick for the approach of a glider model in 

order to be able to appropriately control the spoilers or a 

crow position using one of the other controls. It may be 

more advantageous to either design the function of the 

C1 joystick to be switchable (see Example 4, beginning 

on page 247) or to leave the control of the brake system 

at the joystick and to control the motor through one of 

the other controls or even with a switch! Since this type 

of model does not normally have a motor, and just a 

"start assistance" function to either "lift" the model in 

the sky with full force or, in any case, to "tow" it with 

"half" force by a wind fi eld, Therefore, the motor can be 

switched on and off without having to release one of the 

joysticks – even in the approach. The selection is not 

diffi cult with the mx-20 HoTT transmitter.

For the control of the motor you use a two-stage switch 

SW 3 or 8 or, even better, one of the two three-stage 

switches CTRL 9 or 10. In any case, select a switch 

which you can reach easily in order to perform this 

option without having to release the joystick. In addition, 

this procedure should take place on the transmitter side, 

which is modifi ed for a holding hand with a manual start 

of the model. In other words: If the model is started from 

the right hand, the motor switch should be assigned to 

one of the switches available on the left side and vice 

versa.

The idea is the same for the control of fl aps, regardless 

of whether only ailerons or fl aps covering the entire 

wingspan (combinations) are raised or lowered.

If everything is now in order, you can begin with the 

programming.
238 Detail program description - Control adjust

 Initial steps for the programming of a new model

Example: Winged model with two ailerons and – initially – without motor propulsion

In the scope of the initial commissioning of a new 

transmitter, in the selection menu ...

"General settings" (page 224)

Batterie type

Batterie warning

Touch Sense

Contrast

Ni-MH

Display light

Region

Voice volume

2

4.7V

0

Euro

3

unlim.

Beep volume 3

BASIC SETTINGS

Own

Stick mode 1

DSC Output PPM10

Pitch min back

Power-on beep yes

Power on warn. unlim

H-J Sandbrunner

... some basic information should be entered. This 

serves various purposes:

In this menu the name of the owner can be entered 

and defaults can be entered for new model memories 

in the lines "Stick mode", "DSC Output" and Pitch 

min". These are then adopted on the activation of a new 

model memory in its basic settings, but can be changed 

there at any time.

In the "Contrast" line, as an alternative to the line with 

the same name in the "Hidden mode" menu, page 28, 

you can adjust the display contrast by changing the 

standard default "0" in a range of ±20. 

The setting in the "Display light" line determines how 

long the display lighting remains illuminated after the 

transmitter is switched on or after the last key actuation.

With the selection of "yes/no" in the "Power-on beep" 

you can determine whether the "Recognition melody", 

which sounds when switching on the transmitter, is 

switched on or off.

In the "Battery type" line you indicate to the transmitter 

whether its power supply comes from a four-cell NiMH 

battery or a single-cell LiPo- battery and in the "Battery 

warning " line you can determine the corresponding 

switching threshold for the battery warning on an 

individual basis. Make sure that you do not enter a 

value which is too low, so that you do not have suffi cient 

time to safely land your model in the event of a battery 

warning.

In the "Power-on warning" line, you can determine, as 

necessary, how long the transmitter should wait after the 

last actuation of an operating element until the activation 

of an optical and acoustic power-on warning, whereas 

the settings in the lines "Touch sensitivity", "Voice 

volume" and "Signal volume" are provided for personal 

comfort.

On the other hand, the setting in the "Region" is 

anything but a matter of taste and is determined by 

statutory regulations: Therefore, when in France, 

only commission the transmitter with the "France" 

setting.

You can leave this menu after completion of your 

"General settings" with the central ESC key of the left 

touch pad to return to the multifunction list.

For the programming of a new model, now use the 

arrow keys of the left or right touch pad to switch to the 

menu ...

"Select model" (page 63)

..., and with the select a free model memory location 

with the arrow keys of the right or left touch pad:

03

04

05

02  free 

01

06

R12

 free 

 free 

 free 

 free 

Immediately after pressing the central SET key of the 

right touch pad for the confi rmation of this selection, the 

type of model to be programmed is requested:

Select model type

Since we want to work with a winged model in this 

section, the symbol for a winged model is confi rmed by 

pressing the central SET key of the right touch pad. The 

display switches back to the base screen.

Notice:

• Of course, you can also use the predefi ned default 

"winged model" supplied with the receiver as model 

memory 01 for the programming of your fi rst model.

• Once the "Select model type" option has been 

opened, the process can no longer be canceled! 

Even if you switch off the transmitter, this selection 

must be made! In any case, you can undo this by 

subsequently deleting the respective model memory.
Detail program description - Control adjust 239

• If the battery voltage is too low, you cannot switch 

models for safety reasons. A corresponding message 

appears in the display:

not possible now

voltage too low

Once this fi rst hurdle is cleared, the connection of the 

receiver built into the model to this model memory can 

be made in the menu ...

""Basic model settings" (page 68 ... 73)

. For this purpose, switch to the line "RF bind":

1

n/a n/a

BD1

GRAUBELE

BD2

RF transmit n/v OFF

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Notice:

After confi rmation of the model selection in the base 

screen, if you confi rm the message appearing in the 

screen for a few seconds ...

BIND N/A

OK

... by pressing the SET key of the right touch pad, you 

automatically come to this line.

In this line you delete the connection process between 

model memory and receiver, as described in detail on 

page 69. Otherwise, you cannot address the receiver.

Afterwards, using the arrow keys  of the left or right 

four-way pad, move up to the fi rst line and begin with the 

actual model programming in the "Mod. Name" line:

1

n/a

BD1 BD2

R12 n/a

bind

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

Now enter the "Model name" here by briefl y pressing 

the central SET key of the right touch pad to switch to 

the character map:

 !"#$%&’()+,–./012

3456789:;

Mod Name GRAUB

FGHIJKLMNOPQRSTUVWX

YZ[¥]^_`abcdefghijk

?@A BCDE

If applicable, the defaults adopted from the "General 

settings" menu for "Stick mode" and "DSC output"

are also checked and changed as necessary.

In the menu ...

"Model type"

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1 +100%

SEL

... the principle arrangement of the servos in the model 

is selected and communicated to the transmitter. The 

following selections are available:

"Motor at C1"

• "none"

Trimming works independently of the joystick position 

and the "Brake settings" submenu of the "Wing 

mixers" menu, beginning on page 146, is available 

without limitation.

The "Throttle too high" warning message, see 

page 36 and/or 61, and the "Motor stop" option are 

deactivated.

• "(Idle) front or rear"

C1 trimming is affected in the front or rear and the 

"Motor stop" option is activated. 

If the throttle joystick is too far in the full throttle 

direction when switching on the transmitter, this is 

indicated to you with the warning message "Throttle 

too high".

In parallel to this, the "Brake settings" submenu of 

the "Wing mixers" menu, beginning on page146, 

is only available if "none" is entered in the "Motor" 

column for the currently active fl ight phase in the 

"Phase settings" menu, page 128.

In the next two lines, the principle arrangement of the 

servos in the model is selected and communicated to 

the transmitter:

+100%

SEL

Tail type

Motor at C1

Normal

None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1

Tail type: "Normal", "V-ta(il)", "Delta/fl " or 

"2ELSv3+8"
240 Detail program description - Control adjust

"Aile/fl aps": 1 or 2 AIL servos and 0, 1, 2 or 4 FL 

servos

Since we want to actuate the brake system of the "Brake 

settings" submenu under the "Wing mixers" menu with 

the C1 joystick, we will leave the setting to the outer 

right in the "Brake off" set to "Input 1". With the "Offset 

value" to the left of this, you should only place the mixer 

neutral point at the point where the brake system is 

retracted or inactive. If, in the process, the offset is not 

place completely at the end of the control path, the rest 

of the path is "idle travel", which means the mixer is not 

infl uenced in this range of the joystick movement.

By now, the servos should be plugged into the receiver 

in the standard Graupner sequence:

Receiver power supply

Free or left aileron 2 or aux. function

Rudder

Aileron or left aileron

Elevator or 1st elevator

Receiver power supply

Airbrake or throttle servo

or speed controller (electric motor)

Right aileron or aux. function

Flap or left flap

Right flap or free or aux. function

Comments:

• If a V-tail unit should move incorrectly either "high/

low" or "left/right", please observe the information in 

the table on page 57 in the right column. The same 

process applies for the ailerons and fl aps.

• The settings described in the following are based on 

a model with "normal" tail unit and "none (motor)". 

The settings are adopted for models with a V-tail with 

practically no changes at all. However, the transfer of 

this information is not so simple for delta/fl ying-wing 

models. Therefore, a special programming example 

for this model type is provided on page 272.

In the menu ...

""Servo setting" (page 90)

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

... the servos can now be adapted to the requirements 

of the model for "Rotational direction", "Neutral 

position", "Servo travel" and "Travel limit".

In this sense, all settings which serve for the 

compensation of the servos and minor adaptation to the 

model are "necessary".

Notice:

• The maximum possible throw of a Graupner servo 

is 150% per side, based on both mechanical and 

electrical reasons. For example, if the the sum of the 

values of the columns "Center" and "Servo travel" 

exceed this limit, the respective servo can no longer 

follow the control commands starting from this point. 

Therefore, please bear in mind that the mixer and 

settings in the "Dual Rate / EXPO" menu also have 

an infl uence on the servo travel. 

• The settings options provided in this menu for 

asymmetric servo travel do NOT serve for achieving 

differentiations for ailerons and/or fl aps. There are 

options better suited for this purpose in the "Wing 

mixers" menu.

In the last column, "Lim. +", the basic settings can and 

should be taken back signifi cantly from 150% in each 

case. 

The values entered in this position act as a quasi 

"limiter", whereby the setting is actually for which point 

of travel the respective servo may not exceed, so that it 

does not start up mechanically and thus unnecessarily 

draw current. In this case the End of the available 

mechanical play on the servo, rudder and/or steering is 

crucial for the value to be set.

An example of this would be the selection of a model 

with cruciform tail, with which the rudder moves in a 

wedge-shaped cutout of the elevator. In order to prevent 

the rudder on the elevator starting up and possibly 

blocking it, the travel is normally mechanically adjusted 

(at the linkage) so that the rudder does not start with the 

full throw of the joystick. As long as the rudder is only 

controlled with the corresponding joystick, there will not 

be any further problems with this. Currently, however, in 

addition to the normal rudder signal a mixer infl uences 

the rudder, such as an "AI  RU" mixer (aileron to 

rudder), and the two signals can combine to have an 

excessive effect. 

A correctly set limit of travel intercedes precisely at this 

point and thus reliably prevents the mechanical starting 

of the rudder. The limit of travel should, however, not be 

too small, so that the rudder throw is permanently and 

excessively limited.

Of course, the travel on both sides could, of course, 

also be reduced to the that a start-up would not even 

occur with an addition of the maximum values. With this 

method, however, the prevention of an actually occurring 

event would result in a permanent reduction of the 

normal rudder throw.

The
Detail program description - Control adjust 241

menu ...

"Joystick setting" is not only interesting for pilots of 

models with motors. (page92)

Ch.1

Aile

Elev

Tr time +

4

4

4

0.0s

0.0s

0.0s

Rudd 4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

GL

St

In addition to the generally interesting adjustment 

of the increments in the column St" (number of trim 

increments for each "Trim lever click") of the digital 

trimming – separately adjustable for each of the four 

trim levers – in the case of the (later) programming of 

fl ight phases in the second column of this menu you can 

select whether the trimming of transverse, altitude and 

side should work "globally" in equal measure over all 

fl ight phases or separately in each (fl ight) "phase".

The "Time" column, on the other hand, is not of interest 

for this initial programming.

With the previous settings, you can basically fl y winged 

and motor models – the latter if you have set the idle 

joystick direction correctly in the "Motor at C1" of 

the "Model type" . However, the "fi ne-tuning" is still 

missing. The fi ne-tuning certainly adds to the enjoyment 

of fl ying over the course of time. Therefore, if you can 

already fl y your model safely, you should delve into the 

menu...

"Wing mixer" (page 146 ... 163)

... where various options are available depending on the 

specifi cations made in the "Model type" menu, page 82.

Since in this section we are dealing with a model 

with only two servos in the wings, the Multi-fl ap menu 

beginning on page 157 is not shown.

Aile.diff.

Brake settings

0%

AI 0%

WING MIXERS

EL AI 0% 0%

–––

–––

RU

normal

Therefore, we will begin with the submenu ...

BRAKE SETTINGS

normal

normal

off

If this display appears, you model is equipped with 

a motor, contrary to the assumption of this section, 

and therefore you have selected "front/rear" instead 

of "none" in the line "Motor to C1" of the "Model 

type" menu, page 82. Therefore, change this setting 

temporarily or change the "yes" entry in the "Motor" 

column of the " Phase setting " menu, page 128 to "no" 

for the currently active fl ight phase –Phase 1 in this 

case.

Pha1

Pha2

Pha3

Name motor

Pha4

Pha5

 normal

Start

Strecke

–

–

yes

yes

yes

yes

no

–

–

...

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red

0%

0%

0% 0%

0% 0%

WK WK2

normal

After this statement about mutual dependencies, back 

to the topic:

If the ailerons should be elevated for braking, an 

appropriate value is then entered in the "Crow" line 

after activation of the value fi eld of the "AILE" column. 

In addition, a value should always be entered in the 

line below it, "D.red." (differentiation reduction), which 

corresponds to the value you entered or would like to 

enter on the fi rst page of the "Wing mixers" menu in 

the line "Aile.diff." (see fi gure above)! With this entry, 

on actuation of the brake joystick, the set aileron 

differentiation is hidden again proportionally in order to 

increase the downward the throw of the raised ailerons 

and thus signifi cantly improve its effect in the braking 

phase.

A setting of the "Elevat curve" mixer is then only 

necessary if the fl ight speed of the model changes too 

dramatically on actuation of the brake system. In any 

case, you should try out the setting at a suffi cient and 

readjust, if necessary, whereby you should focus less 

on the fl ight position than on maintaining the "normal" 

fl ight speed of the model. Otherwise there is the risk that 

the model plunges when engaging the brake system, 

because it became too slow in the meantime:
242 Detail program description - Control adjust

Input

Output

Point 1

–19%

–6%

–7%

Brake

Normal

EL

Curve on

After exiting the "Brake settings", the "Aileron 

differentiation" can be set:

This serves to eliminate the negative torque. The 

downward defl ected aileron normally generates a higher 

level of resistance during the fl ight than when defl ected 

upward the same distance, whereby the model is pulled 

to the "wrong" side. In order to prevent this, with the 

input of a differentiation of the travel of the respective 

servo defl ected downward is reduced accordingly. A 

value between 20 and 40 %, in this case, seldom arises, 

however, the "correct" setting must be sought.

The option "AI  RU" (Aileron  rudder) also serves 

a similar purpose, as well as for the comfortable control 

of a model. A value around 50 % is a practical value 

to start with. However, this function should be made 

switchable with the assignment of a switch if you ever 

have aerobatic fl ight ambitions. (The author, for example, 

switches off this mixer "automatically" when switching 

to the "Speed" fl ight phase, in which he assigns both 

options to the same switch accordingly.)

The last option of the "Wing mixers" menu, "EL  AI" 

mixer, is not currently of interest.

If the model-specifi c settings were made thus far, 

the initial start can be considered. If course, at fi rst 

you should perform a "dry run", meaning you should 

carefully check all the settings once again on the 

ground. Incorrect programming can damage more than 

just the model! In case of doubt, ask the advice of an 

experienced model pilot.

If you should fi nd during the testing that one or multiple 

settings must be made for the adjustment of the rudder 

effects to your control habits, the control throws are too 

long or short on the whole, you should adjust this in the ... 

""Dual Rate / Expo" menu (page 108)

... to your own requirements and habits.

With "Dual Rate" the relationship of the joystick travel to 

control travel is adjusted, see page 108:

100%

100%

100%

Ail

Ele

Rud

DUAL

–––

–––

–––

SEL

On the other hand, if the maximum throws are OK and 

only the reactions around the center position are to 

strong for more sensitive controls, then the "exponential" 

functions comes (additionally) into play: 

0%

0%

0%

EXPO

–––

–––

–––

SEL

Ail

Ele

Rud

If a switch is also assigned, switching can even take place 

between two dual-rate/expo settings during the fl ight.

This is similar for the option ...

"Channel 1 curve" (page 116)

Input

Output

Point ?

0%

0%

0%

C1

normal

Curve

Curve off

With this option, one or multiple points of the control 

curve of the throttle/brake joystick can be infl uenced in 

such a way that a pleasant or even purposeful behavior 

is guaranteed.

An example of this would be the "dead" travel of 

spoilers. The fl aps fi rst pass through this after a certain 

"idle travel" of the brake joystick from the wing. With a 

corresponding "bending" of the curve, the "dead' travel 

is covered more quickly. The spoilers come out from 

the wing earlier and then the remaining travel can be 

controlled with greater sensitivity. (This also applies for 

the control of a motor in the same manner, which can be 

controlled through C1 as an alternative.)

After this, you must defi ne the behavior of the receiver in 

the event of a failure in the ...
Detail program description - Control adjust 243

"Fail safe" menu (page 196)

FAIL SAFE

Pos

hold

123

4

5

6

 DELAY : 0.25s STO

... because "doing nothing" is the worst thing which can 

be done for a winged model.

In the transmitter's home position, "Hold" is specifi ed 

and "Hold" means that the receiver continuously sends 

the last correctly recognized control impulse to the 

servos in the model. In the best case scenario the 

model fl ies straight ahead for an indefi nite amount of 

time and then hopefully "lands" somewhere without 

causing signifi cant damage! However, if something like 

this happens in the wrong place at the wrong time, the 

model ma y become uncontrollable and "tear" across the 

fl ight fi eld completely out of control, putting the pilot and/

or spectators at risk. Therefore, it would obviously be 

benefi cial to program the the function "Motor off" at the 

very least, in order to prevent such risks.

With electro gliders, on the other hand, the fail-safe 

setting "motor off" can also be used, for example, for 

outlanding, to reliably stop the motor or its propeller 

by immediately switching off the transmitter after the 

landing.

The author usually prefers a "braking fi nish" within 

eyeshot to fl oating off "somewhere else". 
244 Detail program description - Control adjust

 Integration of an electric drive into the model programming

An electric drive can be controlled in different ways: 

The simplest method to integrate one such drive into 

the model programming is with the use of a throttle/

brake joystick (C1). However, since this is already 

specifi ed for the brake system in the course of the model 

programming described above, either the switchable 

solution described beginning on page 247 or even the 

use of an alternative control is possible. 

As such, one of the two three-stage switches CTRL 9 

or 10 is better suited than the proportional rotary control 

CTRL 6 ... 8. (Unlike rotary controls, switches can be 

operated with one fi nger without having to release 

the joystick). An alternative would also be one of the 

two-stage switches. Basically, the switch should be 

positioned conveniently within reach.

Before we turn to the individual examples, it is important 

must be noted that all inputs in the Control adjust menu 

can be selectively programmed as fl ight-phase specifi c 

("PH" in the "Type" column) or model memory specifi c 

("GL" in the "Type" column)!

However, since the drive should usually be available 

depending on the current fl ight phase, we recommend 

leaving the standard default "GL" ("global") in the "Type" 

column which your are using.

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

A common option in the following examples 1 ... 5, the 

automatic tracking of the elevator trimming in the power 

fl ight, should also be mentioned at the beginning of this 

section:

If it becomes apparent after the initial power fl ights 

that the model must be continuously corrected with the 

elevator while the motor is switched on, this situation 

can be corrected by setting a free mixer and adjusting it 

accordingly. For this purpose, switch to the menu ...

""Free mixers"

... and program one of the linear mixers M1 ... 8 or, if 

applicable, also one of the curve mixers K9 ... 12 from 

"channel controlling the motor" according to "Ele", e. g. 

of "8  Ele":

typ fr to

M1

M2

M3

8 EL

M4

M5 ?? ??

?? ??

?? ??

?? ??

On its second screen page, the required – usually 

low – correction value is entered:

L.MIX 1

0%

Offset

SYM ASY

8 EL

Mix input

+4% +4%

Notice:

The adjustment of a curve mixer is described in detail in 

the section "Channel 1 curve" starting on page 116.

Example 1

Use of a proportional rotary control 

CTRL 6 ... 8

If one of these controls is used, the connection is very 

simple. Only the motor controller (speed control) has to 

be connected to a free servo connection 5 ... 12 of the 

receiver. 

Bear in mind that, depending on the model type and 

number of aileron and fl ap servos, the output 2 + 5 or 6 

+ 7 are already linked. 

Therefore connect your speed controller to the next free 

input and assign the selected input – for example, "Inp. 

8" – one of the proportional rotary controls CTRL 6 ... 8. 

For example, CTRL 7. This is carried out in the menu ...

""Control adjust" (page 96)

With the arrow keys  of the left or right touch pad, 

select the desired line. Then, by pressing the central 

SET key of the right touch pad, you active the "Switch 

and control assignment". Now turn the knob of the 

proportional rotary control. After a short time, the entry, 

e. g. "Control 7", appears in the inverse fi eld. 
Detail program description - Control adjust 245

the selected control close to "Full throttle" so that the 

marking frame is only placed around one value fi eld. 

Now enter a value of at least 1 s, ...

Input 5

– time +

0.0

0.0

0.0

1.0

Input 6

Input 7

Input 8

0.0

0.0

0.0

0.0

normal

... with which a movement of the proportional control 

in the "ON" on direction which is too fast is processes 

move gently, and you can check immediately this by 

switching to the "Servo display".

Notice:

• No delay is entered on the "OFF" side, so that the 

drive can be switched off instantly at any time. This 

does not additionally stress the drive, because it 

merely "runs down".

• If you have defi ned fl ight phases in the "Phase 

setting" and "Phase assignment" menus, the 

settings described above must be made in the same 

manner for each active fl ight phase. Otherwise, you 

may wonder why the drive motor begins running at 

half power after a phase change, but does not react 

to movements or the rotary knobs ...

The adjustment of the appropriate control travel and 

directions for the motor control (speed controL) is 

normally carried out in the "Control adjust" menu in the 

"- Travel +" column. Alternatively, you can also carry out 

these settings in the menu ... 

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

GL

GL

GL

GL

typ

Ct7

Since the drive should usually be available depending 

on the current fl ight phase, if applicable, you should 

leave the standard default "GL" in the "Type" 

column – as already mentioned earlier in this section. 

If applicable, for the necessary adjustment of the 

appropriate control travel for the motor control (speed 

control), use one of the arrow keys to switch to the right 

from the "Offset" column to the "- Travel +" column.

typ fr to

M1

M2

M3

8 EL

M4

M5 ?? ??

?? ??

?? ??

?? ??

If you now switch to the Servo display" by 

simultaneously pressing the keys of the left touch pad 

and then actuate the rotary control, you will see the 

columns of Channel 8 "wander from one side to the 

other and back.

However, if you rotate the proportional rotary control 

too fast – in practice – the resulting abrupt motor startup can briefl y strain the entire drive string. You should 

defi nitely counteract this effect ahead of time with an 

appropriate value in the "Time" column for such cases.

Therefore, using one of the arrow keys, switch one 

column to the right, to the "Time" column and then move 

""Servo adjustment" (page 90)

S4

S5

S6

Rev centr trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S7

S8

.

Example 2

Use of a three-stage switch CTRL 9 or 10

This variant realizes a three-stage speed setting, such 

as Motor OFF, "half" and full power.

A corresponding motor control (speed control) is 

required on the receiver side.

The required settings are basically the same as those 

described under Example 1. Therefore, the same 

comments and recommendations also apply.

Apart from the infi nitely variable motor control under 

Example 1 and the three-stage motor control in this 

example, the selection of the two control types only has 

an effect on the type of clock control, see page 252.

Notice:

• By shifting the neutral position and then adjusting the 

travel so that the offset value on the side to which the 

neutral point was shifted is subtracted from the travel 

and added to the other, the "Half throttle position" 

can be infl uenced in the "Control adjust" menu. 

Therefore, with an offset value of -20 %, for example: 

+80 % on the minus side of the travel setting and 

+120 % on the plus side and vice versa.

• If you have defi ned fl ight phases in the "Phase 
246 Detail program description - Control adjust

setting" and "Phase assignment" menus, the 

settings described above must be made in the same 

manner for each active fl ight phase. Otherwise, you 

may wonder why the drive motor begins running at 

half power after a phase change, but does not react 

to movements or the switch ...

Example 3

Use of a two-stage switch SW 2, 3 or 8

This variant realizes a purely ON/OFF function.

On the receiver side, either a simple electronic 

switch or – if a gentle motor start-up, for example, is 

desired – an appropriate motor control (speed control) 

is required.

With the exception of the assignment of a different 

control, the settings required for this are essentially the 

same as those described under Example 1. Therefore, 

the same comments and recommendations also apply. 

Apart from the infi nitely variable motor control under 

Example 1 and the two-stage motor control in this 

example, the selection of the two control types only has 

an effect on the type of clock control, see page 252.

Only the type of representation of the selected switch in 

the dispay of the menu ...

""Control adjust" (page 96) differs from the 

description there.

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

–––

–––

GL

GL

GL

GL

typ

Like with example 1, you also switch to the line of a free 

input, activate the "Control and switch assignment" in 

the third column and then move the selected control, 

in this case Switch "2" from the desired Motor OFF 

position to Motor ON.

In this case – as already mentioned earlier in this 

section – you leave the standard default "GL" in the 

"Type" column.

The setting of the appropriate control travel for the 

motor control (speed control) is made in the "- Travel +" 

column. If the motor should up gently with the use of a 

motor control (speed control), an appropriate delay time 

can be set – as described in Example 1 – in the "- Time 

+" column: 

Input 5

– time +

0.0

0.0

0.0

1.0

Input 6

Input 7

Input 8

0.0

0.0

0.0

0.0

normal

All other settings - as already mentioned earlier in 

the example - take place analogously to Example 1. 

Therefore, the same comments and recommendations 

apply.

Notice:

• No delay is entered on the "OFF" side, so that the 

drive can be switched off instantly at any time. This 

does not additionally stress the drive, because it 

merely "runs down".

• If you have defi ned fl ight phases in the "Phase 

setting" and "Phase assignment" menus, the 

settings described above must be made in the same 

manner for each active fl ight phase. Otherwise, you 

may wonder why the drive motor begins running at 

half power after a phase change, but does not react 

to movements or the switch ...
Detail program description - Control adjust 247

 Control E-motor and crow alternatingly with C1 joystick

Example 4

Before we discuss the programming of this fourth 

example or turn the to the expansion of the previously 

described basic programming, a few words should be 

said about the position of the throttle/brake joystick 

with "Motor OFF" or "Brake OFF". Normally the C1 

control joystick is moved forward for the throttle control 

and backward for the extension of the brake. If, in this 

"classic" assignment, you switch to the brake system 

with Motor "OFF" (= joystick "back"), for example, 

"full brake" would be applied after the switch time you 

specifi ed in the "Phase setting" menu, or vice versa, 

if you switch to drive with the "brake retracted" the 

motor would be switched to "full power" within this time 

range...

A "glider pilot" can make the best of this 

"Emergency" – normally with "brake retracted = front" – 

by switching to motor "ON" only if necessary and then 

the power decreases, if applicable (and hopefully you 

will not forget to push the C1 joystick "forward" again 

when switching back). A typical "motor pilot", on the 

other hand, operates in the opposite manner, only 

switching to the brake if necessary, etc... You can also 

combine the "Zero point" of both systems to avoid 

confusion, whereby a "glider pilot" would tend prefer the 

"front" and a "motor pilot", on the other hand", would 

likely prefer the "rear". 

Whatever the case may be, themx-20 HoTT 

transmitter enables both variants. In the following text, 

however, the combination of the two "OFF" positions 

to "front" is assumed. However, if you have a different 

preference, it is not a problem: The only difference 

from the described version lies in the logical selection 

of "Throttle min rear/front" and, if applicable, of a 

SEL

vorne

–90%

STO

Tail type

Motor at C1

Aile/flaps 2AIL

M O D E L T Y P E

Brake Off In 1

Normal

In the process, if the offset point is not placed 

completely at the end of the control travel, the remainder 

of the travel is "idle" up to this limit. This idle path 

ensures that all brake settings remain at "neutral", even 

with minor deviations from the limit of the brake fl ap 

control. At the same time, the effective control path is 

automatically spread to 100 %.

For this reason, in the next step it must be ensured that 

the infl uence of the C1 joystick on the motor can be 

infl uenced. For this purpose, switch to the menu ...

"Phase setting" (page 128)

... and assign a meaningful name, such as "normal", 

from the list for "Phase 1" after activation of the selection 

fi eld in the "Name" column. The asterisk in the second 

column indicates which phase is currently active. 

As long as no phase switches are assigned, this is 

always Phase 1. Give "Phase 2" the name "Landing" in 

accordance with the example.

In the "Ph.Tim" column you can assign a so-called fl ight 

phase timer for the measurement of the motor running 

time and/or the gliding times as necessary for each 

phase. You could, for example, assign one of the "Timers 

1 ... 3" to the "Normal" fl ight phase in order to measure 

the total motor run time through the C1 joystick:

corresponding brake offset in the menu ... 

""Model type" (beginning on page 82)

Here you fi rst specify in the "motor" line whether the 

throttle minimum position (= Motor "OFF" position) 

should be at the "front" or "rear" - as already discussed: 

In the following programming example, "Motor OFF" and 

"Brake OFF" are combined at "front":

Tail type

Motor at C1

Normal

Aile/flaps 2AIL

M O D E L T Y P E

Brake Off In 1 +100%

SEL

front

Notice:

With the selection of "Throttle min front/rear" the 

trimming will then only have an effect in the "idle" 

direction of the motor and is not the same as with the 

"none" entry, having the same effect at every position of 

the C1 joystick. Since the C1 trimming is not normally 

used with electric drives, however, this has no further 

relevance.

You adjust the "according to your model, in this case 

"normal".

In the "Aileron/fl aps" line you enter the correct number 

of aileron and fl ap servos – in this example "2 AIL".

In the last line you leave the standard entries for the 

selection of "Brake retracted = rear". On the other hand, 

if you prefer "Brake retracted = front", select the "Brake 

offset" line and defi ne the offset point – as described on 

page 83 – as "front":
248 Detail program description - Control adjust

menu. For example, you name the phase for the front 

switch position "normal" and "landing" for the rear 

position (or vice versa):

PHASE ASSIGNMENT

A B C D E F 

2

prior combi

2 Landing

These phase names then appear in all fl ight-phase 

dependent menus and, of course, also in the base 

screen of the transmitter.

Now switch to the "Landing" fl ight phase and in the 

"Crow" line of the submenu ...

""Brake settings" (page 160)

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red 0%

0% 0%

0% 0%

WK WK2

Landing

0%

... of the "Wing mixers" menu, set the desired throw of 

the ailerons with actuation of the C1 joystick ("brake") 

upward. Then, if applicable, switch to the "FL" column 

in order to specify the desired through of the fl aps with 

C1 actuation downward (hidden in the fi gure above). 

This fl ap position is referred to as "Crow position" or 

"Butterfl y; see also page 160.

In the line "D.red" (differentiation reduction), enter a 

value which corresponds to the value you entered or 

enter on the fi rst page of the "Wing mixers" menu in the 

Pha1

Pha2

Pha3

Name Sw.time

Pha4

Pha5

Normal

Strecke

–

–

–

–



Landing

1.1s

0.1s

0.1s

0.1s

1.1s

Then you must assigned these two fl ight phases to a 

switch with which you can switch between the two fl ight 

phases during the fl ight. In this case, a single switch is 

suffi cient. It should be easy to reach, however, so that 

you can still switch between "motor" and "brake" during 

a landing approach, for example, without having to 

release a joystick.

The assignment of the selected switch takes place in the 

menu ...

"Phase assignment" (page 134)

Select the switch symbol under "C" with one of the arrow 

keys. After briefl y pressing the central SET key of the 

right touch pad, actuate the desired switch, such as 

"SW 2".

PHASE ASSIGNMENT

A B C D E F 

1 Normal

2

prior combi

Both switch positions, in other words ON (I) and OFF ( )

 are initially assigned in the bottom right of the display to 

the phase "1 normal". With one of the arrow keys, select 

this value fi eld and then, by briefl y pressing the central 

SET key of the right touch pad, activate the selection list 

of the phases which you set up in the "Phase setting" 

Pha1

Pha2

Pha3

Name ph.Tim.

Pha4

Pha5

Normal

Strecke

–

–

–

–

 Clk 1

Landing

Then the timer is controlled through a corresponding 

control switch to be defi ned on the C1 joystick. As soon 

as you switch to the "Landing" fl ight phase, this fl ight 

phase timer is automatically stopped and hidden in the 

base screen. More about this can be found on page 142.

Now move the marking frame over the "Ph.Tim" column 

to the "Motor" column to the right. Here you can decide 

with "yes/no" in which phase the motor is controlled by 

the throttle/brake joystick and the brake system to be 

adjusted in the "Brake settings" submenu of the "Wing 

mixers" menu should be shut off (= "yes") and vice 

 versa (= "no"):

Pha1

Pha2

Pha3

Name motor

Pha4

Pha5

Normal

Strecke

–

–

–

–

 yes

Landing no

Now move the marking frame once more to the right and 

enter an appropriate switching time after activation of 

the value fi eld of the "Sw.Time" column; for example:
Detail program description - Control adjust 249

line "Aile.diff."

With the "Elevat curve" mixer the normally occurring 

"Upward tilting" of the model on the raising of the 

ailerons can be automatically suppressed. The suitable 

correction values for the respective value must be 

tested out through fl ight. Set this mixer so that the fl ight 

speed of the model does not change too much with the 

brake system extended in comparison with the "normal" 

fl ight speed. Otherwise, there is the risk, among other 

things, that the model plunges when the brake system 

is retracted, e. g. for the extension of a landing approach 

which is too short.

If everything is correctly set so far, only the motor is 

controlled with the C1 joystick in the "normal" fl ight 

phase, whereas this should be switched off in the 

fl ight phase "landing" (Servo 1 in "Servo display" 

independently of "Throttle min front/rear" to -100% or 

adequately for a servo travel setting deviating by 100 

%, if necessary). In this fl ight phase the C1 joystick 

then only controls the raising of the ailerons and, if 

applicable, the lowering of the fl aps with the neutral 

point in the C1 control position selected per offset.
250 Detail program description - Control adjust

 C1 joystick switchable between E-motor and spoiler

Example 5

If, contrary to the assumptions of the preceding Example 

4, the model has additional spoilers or only spoilers, 

they can be incorporated into the control of the model by 

means of the following programming.

For this purpose, program the menus "Model type", 

"Phase setting" and "Phase assignment" in the same 

manner as described under Example 4. The settings 

described there in the "Brake settings" submenu of 

the "Wing mixers" menu, on the other hand, are only 

relevant if you would like to use an additional crow 

system in parallel to your spoilers.

With the settings described under Example 4, the 

control of the E-motor and, if applicable, that of a 

crow system will function as usual. Only the control 

of a spoiler connected to Output 8, for example, must 

additionally be programmed. For this purpose, switch to 

the menu ...

"Control adjust" (page 96)

... and switch to the fl ight phase "normal". Now, using 

the arrow keys, switch to the "Offset" column of the 

line "Inp. 8". After activation of the value fi eld by briefl y 

pressing the central SET key of the right touch pad, 

change the offset value in the now inverse value fi eld of 

Input 8 until your spoilers are "retracted" again:

Input 5

offset

0%

0%

0%

Input 6

Input 7

Input 8 –––

–––

Normal

–––

–––

–100%

Confi rm this setting by briefl y pressing the central ESC

key of the left key pad or the central SET key of the right 

touch pad and then switch to the center column to the 

left. Now switch to the fl ight phase "Landing" and then 

briefl y press the central SET key of the right touch pad. 

The display shows the window ...

Input 5

offset

0%

0%

0%

–––

–100%

Eing. 6

Eing. 7

Input 8 –––

––– Move desired switch –––

or control adj.

Landing

Now move the C1 joystick As soon as this is recognized, 

"Ct1" appears in the display instead of "---":

Input 5

offset

0%

0%

0%

Input 6

Input 7

Input 8 Ct1

–––

Landing

–––

–––

–100%

Leave the offset value in this fl ight phase

to "0 %". If necessary, however, you may have to change 

the leading symbol of the travel setting to reverse the 

control direction by switching the travel setting from 

+100 % to -100 % in the "Travel" column.

Now we are practically fi nished. Check the programming 

in the "Servo display" menu, which you can reach from 

the base screen of the transmitter as well as nearly 

every other menu position by simultaneously pressing 

the keys  of the left touch pad. You will discover that 

"Servo 1" (motor control) is controlled in the "normal" 

phase and in the "landing" phase only the spoiler is 

controlled at "Servo 8" and, if applicable the aileron and 

fl ap servos – just as we intended.
Detail program description - Control adjust 251
252 Detail program description - Control adjust

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

–85%

STO

–––

–––

Ct1 –––

In order to assign the control switch you just crated to 

the desired timer, switch to the menu ...

""Timers (gen.)" (page 138 ... 141)

..., and, with the arrow keys, select the line "Top", to 

which the "Tim(ers)" are assigned by standard. In this 

line, move the marking frame over the "Timer" column to 

the right, to the column above the switch symbol, using 

the appropriate arrow key of the left or right touch pad. 

Now press the central SET key of the right touch pad 

twice: Pressing once activates the switch assignment 

and tapping again opens the list of the "expanded 

switches":

Model time

Akkuzeit

Oben:

Mitte: Flug

Alarm

0:34h –––

1:23h

0s

0s

Stopp –––

–––

SEL

Control/fix sw

C1 C2 C3 C4 FX

FXi C1i C2i C3i C4i

Now select the previously programmed control switch, 

Ct1 in the example, and assign it to the timer by briefl y 

pressing the central SET key of the right touch pad:

Model time

Batt. time

Top :

Centr:Flight

Alarm

0:34h –––

1:23h

0s

0s

Stop C1

–––

SEL

The timer in the base screen now starts with movement 

of the C1 joystick toward full throttle and stops if you pull 

the C1 joystick back over the switching point. 

Example 1 of the preceding pages

If you have decided to continue with the model 

programming described on the previous pages in 

Example 1 on page 244, fi rst switch to the menu ...

"Control switches" (page 123)

... and select the line of a control switch which has not 

been assigned yet with the arrow keys. After activation 

of the control assignment by briefl y pressing the central 

SET key of the right touch pad, the following window 

appears:

SEL

+75%

0%

0%

G1

G2

C3

C4 –––

CONTROL SWITCH

Gb1

Gb1

–75%

STO

–––

––– Move desired –––

control adj.

Now simply move the respective proportional rotary 

control, e.g. CTRL 7, from the motor "OFF" position in 

the motor "ON" direction.

The switch to the column above STO using the 

appropriate arrow key and move the selected control 

near the motor "OFF" position and defi ne the switch 

Examples 4 and 5 of the preceding pages

If you have decided to continue with the model 

programming on described on the previous pages for 

Example 4, page 247 or 5, page 250 or you intend to 

use the C1 joystick (throttle/brake joystick) for the power 

regulation completely independently of this example 

programming, you can use a control switch for the 

automatic starting and stopping of the timer. For this 

purpose, fi rst switch to the menu ...

"Control switches" (page 123)

... and select the line of a control switch which has not 

been assigned yet with the arrow keys. After activation 

of the control assignment by briefl y pressing the central 

SET key of the right touch pad, the following window 

appears:

SEL

+75%

0%

0%

G1

G2

C3

C4 –––

CONTROL SWITCH

Gb1

Gb1

–75%

STO

–––

––– Move desired –––

control adj.

Now simply move the C1 joystick (throttle/brake joystick) 

from the motor "OFF" position in the motor "ON" 

direction.

The switch to the column above STO using the 

appropriate arrow key and move the C1 joystick near the 

motor "OFF" position and defi ne the switch point at the 

selected position by briefl y pressing the central SET key 

of the right touch pad. The switch status is shown to the 

right of the control number:

 Timer confi rmation with control or switch
Detail program description - Control adjust 253

point at the selected position by briefl y pressing the 

central SET key of the right touch pad. The switch status 

is shown to the right of the control number:

SEL

0%

0%

0%

C1

C2

C3

C4 –––

CONTROL SWITCH

–85%

STO

–––

–––

Ct6 –––

Notice:

Now place the switching point; but do not put it at the 

limit position of the control, because safe switching is 

not assured when doing so.

Ct1 used in the example here should be "closed" in the 

"full throttle" direction and "open" below the switching 

point. 

Now switch to the menu ...

""Timers (gen.)" (page138 ... 141)

..., and, with the arrow keys, select the line "Top", to 

which the "Tim(ers)" are assigned by standard. In this 

line, move the marking frame over the "Timer" column to 

the right, to the column above the switch symbol, using 

the appropriate arrow key of the left or right touch pad. 

Now press the central SET key of the right touch pad 

twice: Pressing once activates the switch assignment 

and tapping again opens the list of the "expanded 

switches":

Model time

Akkuzeit

Oben:

Mitte: Flug

Alarm

0:34h –––

1:23h

0s

0s

Stopp –––

–––

SEL

Control/fix sw

C1 C2 C3 C4 FX

FXi C1i C2i C3i C4i

Now select the previously programmed control switch 

"Ct1" and then press the central SET key of the right 

touch pad.

Model time

Batt. time

Top :

Centr:Flight

Alarm

0:34h –––

1:23h

0s

0s

Stop C1

–––

SEL

The timer in the base screen now starts with movement 

of the proportional rotary control toward full throttle and 

stops if you pull it back over the switching point. 

Examples 2 and 3 of the preceding pages

If you control your motor with a switch, on the other 

hand, you do not need the described control switch 

described above. It is completely suffi cient if you assign 

the same switch to the timer, so that it also begins to run 

when you switch on the motor.

Tip:

If the motor run time for an E-model is limited by the 

battery capacity, you can have the stopwatch count 

down. Enter the maximum permissible motor run time 

in the "Timer" column, e.g. "5 min", and briefl y before 

the expiration of the permissible time, e. g. "30 s" before, 

have the transmitter issue an acoustic warning signal:

Model time

Batt. time

Top :

Centr:Flight

Timer

12:34h –––

1:23h

0:00

Stop 5:00

Model time

Batt. time

Top :

Centr:Flight

Alarm

0:34h –––

1:23h

0s

Stop C3

–––

SEL

30s
254 Detail program description - Control adjust

 Servos running in parallel

A second servo running in parallel is often required, 

such as when brake fl aps or spoilers installed in the 

wings or the left and right elevator or a double fi n should 

be actuated by a servo or a large rudder fl ap should 

be simultaneously controlled by two servos due to high 

throw forces.

In principle, this task could also be solved by connecting 

the servos together on the model side using V-cable. 

However, this has the disadvantage that the servos 

combined in this manner can no longer be adjusted 

individually and separately from the transmitter – the 

advantage of a fi nely tuned adjustment of the respective 

servos to one another by a computer remote steering 

system would no longer be provided. This is similar 

for the so-called "Channel Mapping" described in the 

scope of the "Telemetry" menu: In comparison to the 

adjustment possibilities of the transmitter, there are also 

limitations with this process.

The fi rst example, therefore, describes the coupling of 

two brake or spoiler servos, the second describes the 

operation of two or more throttle servos and the third 

describes the coupling of two elevator servos.

The "two rudder servos" example on the next page 

describes the coupling of two rudder servos, whereas 

Variant 1 is preferable for applications of this type, 

because with the use of a "cross-mixer", because this 

is quicker and easier to program. Contrary to this, the 

second variant, also permits asymmetric and/or nonlinear curves with the use of the "Free mixer" menu.

Two brake or spoiler servos

For the operation of your brake fl aps and/or spoilers in 

each wing half you have installed a servo and kept the 

default linear control characteristics unchanged in the 

"Channel 1 curve" menu.

Then connect one of the two servos to Output 1, 

provided for this purpose by standard, and the second 

to an arbitrary free receiver connection 5 ... 12, such as 

Output "8". Now switch to the menu ...

" Control adjust" (page 96)

... and, using the arrow keys, assign the "Control 1" in 

the line of Input 8:

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

GL

GL

GL

GL

typ

Ct1

Leave the standard settings for the remaining values. 

If necessary, carry out the required servo travel 

adjustments in the "Servo adjustment" menu. There 

you can also adjust the travel of servo 1 and 8 to one 

another, if necessary.

Important notice:

If you have defi ned fl ight phases in the "Phase setting" 

and "Phase assignment" menus, the settings must be 

made in the same manner for each active fl ight phase. 

Otherwise, you may wonder why only one spoiler can 

be moved as intended and the other remains in its half 

extended position ...

Multiple-motor aircraft

As described above, a model can also be operated with 

two or more motors.

The fi rst throttle servo and/or the fi rst motor control is 

connected as usual to (receiver) Output 1 and each 

additional throttle servo and/or each additional motor 

control is connected to a free (receiver) Output 5 ... 

12. The inputs of the corresponding assigned control 

channels are then each assigned to Control 1; for 

example :

Input 8

offset

0%

0%

0%

0%

Input 9

Input10

Input11

GL

GL

GL

GL

typ

Ct1

Ct1

Ct1

Ct1

Important notice:

Since the motor control unit should be available 

regardless of a currently active fl ight phase, make sure 

to leave the standard default "GL" in the "Type" column.

Two elevator servos

Two elevator servos should be switched in parallel. 

According to the receiver assignment plan, see page 57, 

the receiver output 8 is intended for the connection of 

the second elevator servo.

This would be taken into account on the software side in 

the preconfi guration of a corresponding mixer. You can 

fi nd this in the ...

"Model type" menu (page 82)

In this menu switch to the "Tail" line using the arrow 

keys, activate the value fi eld by briefl y pressing the 

central SET key of the right key pad and select the entry 

"2ELSv3+8":
Detail program description - Control adjust 255

Tail type

Motor at C1 None

Aile/flaps 1AIL

M O D E L T Y P E

Brake Off In 1 +100%

SEL

2ELSv3+8

Then carry out the fi ne-tuning of the travel of the two 

servos "as accustomed" in the "Servo adjustment" 

menu.

Two rudders

We want to switch two rudders "in parallel". The second 

rudder is located at the free receiver output 8.

Variant 1

In the menu ...

"Cross-mixer" (page 194)

... select one of the cross-mixers and enter "8" and "RU" 

in its left and center value fi elds, as shown in the fi gure:

Typ zu Diff.

DUAL MIXER

Mixer1

Mixer2

 8

Mixer3

Mixer4

?? ??

?? ??

?? ??

0%

0%

0%

0%

RU

The same defl ection "", which would take place 

through "Input 8" may not have an effect here. Therefore, 

you should make absolutely sure in the ...

"Control adjust" menu (page 96)

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

GL

GL

GL

GL

typ

normal

–––

... that "Input 8" is set to "free" so that the control 

function is separate from the control channel.

Alternatively, You can set Input 8 in the "Only mix 

channel" to "no control", regardless of the fl ight phase, 

by setting Channel 8 to "only mix":

MIX ONLY CHANNEL

only

normal

789 10 11 12

Variant 2

With this variant a mixer, "Tr Rudd 8" should be set in 

the menu ...

" Free mixers " (page 181)

. In the "Type" column, select the setting "Tr" so that 

the rudder trimming affects both rudder servos:

ty fr to

M1

M2

M3

RU 8

?? ??

M4

M5

?? ??

?? ??

?? ??

Tr

Then switch to the graphic screen and set a symmetric 

mixture of +100%.

L.MIX 1

0%

Offset

SYM ASY

RU 8

Mix input

+100% +100%

"Input 8" should also be programmed to "free" here in 

the "Control adjust" - in all fl ight phases, if applicable. 

However, control function "8" can be separated from 

control channel "8" more easily in the fl ight-phase 

independent menu "Only mix channel", page 193:

MIX ONLY CHANNEL

only

normal

789 10 11 12
256 Detail program description - Control adjust

 Use of fl ight phases

Up to seven different fl ight phases (fl ight statuses) 

can be programmed with settings independent of one 

another within one of the model memories.

Each of these fl ight phases can be called with a switch 

or a switch combination. This makes it possible to switch 

between different settings for the various fl ight statuses, 

such as "Normal", "Thermal", "Speed", "Distance", etc., 

simply and conveniently. However, with the fl ight phase 

programming you can also make slight modifi cations, 

e. g. of mixers, to try out by switching during the fl ight in 

order to fi nd the optimal settings for each model more 

easily.

Before you begin with the actual programming of 

fl ight phases, you should consider whether the digital 

trimming of transverse, altitude and side should have 

be "global" – in other words, the same for all fl ight 

phases – or per "Phase" – in other words, each fl ight 

phase is individually variable. 

If you decide in favor of a phase-specifi c trimming of the 

elevator, for example, switch the menu ...

"Joystick setting" (page 92)

... and change the standard "global" default accordingly.

The same applies for the number

of trimming steps in the column "St":

Tr +

4

4

4

0.0s

0.0s

0.0s

4 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

St

PH

Ch.1

Aile

Elev

time

Rudd

 Example 1 ...

... continuing with the previous programming of an 

electric glider with 2 aileron servos.

AI

AI

EL

RU

The control of the E-drive takes place independently of 

the C1 joystick with one of the two proportional rotary 

controls CTRL 7 or 8 or with one of the two three-stage 

switches CTRL 9 or 10. The motor control is connected 

to receiver Output 9 according to the description 

beginning on page 244 and Examples 1 and two which 

serve as the basis of this continuation. In the "Model 

type" menu, therefore, "None" was selected in the 

"Motor to C1" line, which has the consequence, among 

other things , that the "Motor" column in the "Phase 

setting" menu is hidden and the "Brake settings" 

submenu of the "Wing mixers" menu is available 

without limitation.

1. Step 

"Phase setting" (page 128 )

Pha1

Pha2

Pha3

Name ph.Tim.

Pha4

Pha5



+

+

Normal

Thermal

Speed

+

–

Launch

Initially, one or multiple fl ight phases are provided with 

a specifi c identifi cation ("Name") for the respective 

fl ight status. This identifi cation has no infl uence on the 

programming of the transmitter; it only serves for an 

improved differentiation of the individual fl ight phases 

and is shown later in all fl ight-phase dependent menus 

and in the base screen.

The selection of the respective line, a name and the 

setting of the switching time take place, as "usual", by 

pressing the corresponding key(s) of the two four-way 

touch pads.

Notice:

With the exception of Phase 1, which should always 

be assigned with the name "Normal" since it is 

always active, if the fl ight phases are deactivated, it is 

completely irrelevant which name is assigned to which 

phase!

In everyday use by a model pilot, three to a maximum of 

four fl ight phases are usually completely suffi cient: 

• "Start" with the climb settings

• "Thermal" for "Flying high",

• "Normal" for normal conditions and 

• "Speed" for high gear.

In the "Sw.time" column (switching time) ...

Pha1

Pha2

Pha3

Name Sw.time

Pha4

Pha5



+

+

Normal

Thermal

Speed

+

–

3.0s

2.0s

4.0s

0.1s

Launch 1.0s

... you can defi ne the time for the "cross-fading" when 

switching from any other fl ight phase to this one in order 
Detail program description - Control adjust 257

to enable a "smooth" transition of the various servo 

positions. Thus, an increased stress of the model under 

certain circumstances with a "hard" change of rudder 

or fl ap positions, for example, is prevented The "Status" 

column shows you the currently active fl ight phase with 

an asterisk "".

2. Step 

In order to actually be able to switch between the 

individual fl ight phases, the assignment of one or 

multiple switches is necessary. One of the two threestage switches (CTRL 9 or CTRL 10) is best suited for 

switching of up to three fl ight phases.

Each of the two switch limit positions is assigned to 

one of the fl ight phase switches A ... F, starting from 

the center position. The assignment of the switch takes 

place in the menu ...

"Phase assignment" (page 134)

First select "C" with the marking frame. The briefl y press 

the central SET key of the right touch pad and move 

the switch from the center position to a limit position, for 

example, downward:

PHASE ASSIGNMENT

A B C D E F 

1 Normal

2 6 7

prior combi

Move the switch back to the center position and then 

select "D", and after activation of the switch assignment, 

move the switch to the other limit position, for example, 

to the top:

PHASE ASSIGNMENT

A B C D E F 

1 Normal

2 6 7

prior combi

Now the three-stage switch is programmed. 

Now and additional switch could be assigned for the 

"start" fl ight phase, if applicable. In this case under "A", 

so that the "start" phase is always switched to from 

every other fl ight phase in parallel to the switching-on of 

the motor: 

A B C D E F 

1 Normal

2 6 7

PHASE ASSIGNMENT

prior combi

Then the respective switch positions must be assigned 

corresponding fl ight phases (names). Although you have 

already assigned names for some fl ight phases, the 

phase name "1 normal" still appears in the right of the 

display; see the fi gures above.

First move the three-stage switch to the limit position, 

for example to the top, and switch with the marking 

frame in the display down to the right to the value fi eld 

for the fl ight phase name. Briefl y press the central SET

key of the right touch pad for the activation of the input 

fi eld and select the desired fl ight phase for this switch 

position, in this example "2 Thermal", with the arrow 

keys:

A B C D E F 

2 6 7

2 Thermal

PHASE ASSIGNMENT

prior combi

Proceed in the same manner for the other switch limit 

position, which is assigned the name "3 Speed".

If applicable move Switch 2 and assign this switch 

combination the name "4 Start".

Briefl y pressing the central ESC of the left touch pad or 

the central SET key of the right touch pad completes the 

time name assignment.

The fl ight-phase dependent model settings made before 

the assignment of phase switches are now in the fl ight 

phase "1 Normal". This is the phase which is called 

with the open "Start" switch in the center position of the 

three-stage switch.

3. Step 

In order to not have to carry out all previously made 

settings for the model in the "new" fl ight phase from 

the ground up, we recommend fi rst copying the already 

tested programming of the fl ight phase "Normal" to the 

other fl ight phases. This is carried out in the menu ...

"Copy / Erase" (page 64)

=>

=>

=>

=>

Copy flight phase =>

Erase model

Copy model–>model

Export to SD

Import from SD
258 Detail program description - Control adjust

Here, select the menu item "Copy fl ight phase" with the 

arrow keys and then briefl y press the central SET key of 

the right touch pad.

In the appearing window, "Copy from phase", "1 Normal" 

is selected ...

7

Copy from phase:

3

5 =>

=>

2

4

6

1 Normal Thermal

Speed Launch

... and then briefl y press the central SET key of the 

right touch pad, whereby the display switches to 

"Copy to phase". Now the target is selected (initially "2 

Thermal") and confi rmed by pressing the central SET

key of the right touch pad again. After confi rmation of 

the subsequent safety query, all settings are copied 

according to the selection.

Proceed in the same manner with the other two phases 

("1 Normal" to "3 Speed" and "1 Normal" to "4 Start").

4. Step 

Now three or four phases are programmed, the settings 

are also copied and there is even a "soft" transfer, but ... 

there are still no fl ight-phase specifi c settings.

Now, if applicable, in order to adapt the fl ap positions to 

the different requirements of the individual fl ight phases, 

in the menu ...

"Control adjust" (page 96)

... the standard default "GL" is fi rst changed to "PH" for 

"Phase" in the type column:

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

PH

GL

GL

GL

typ

Normal

–––

Then switch to the "Offset" column and make the 

settings deviating from the "Normal" fl ight phase for the 

ailerons. However, switch to the desired fl ight phase 

beforehand, whose name is shown at the bottom in 

the display, appropriate to the switch position. Both 

positive and negative throw changes are possible. These 

settings are to be made separately for each fl ight phase:

Input 5

offset

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

PH

GL

GL

GL

typ

Normal

–––

–7%

5. Step 

Any necessary phase-specifi c trimming of the elevator is 

made with the help of the digital trimming of the elevator 

joystick. This requires that you have at least set the 

elevator trimming to "Phase" in the "Joystick setting" 

menu - as already shown in this programming example. 

Alternatively, you can also carry out these settings in the 

"Phase trim" menu ...

Normal



0%

Thermal ELEV

0%

QR

Launch

Thermal

Speed

0%

0% 0%

0% 0%

0%

6. Step 

In the menu ...

"Wing mixers" (beginning on page 146)

... the fl ight phase name of the newly activated fl ight 

phase appears at the bottom edge of the display. If 

the switch position is now changed, the name of the 

fl ight phase selected with the switch appears, but 

with the previously copied settings of the fl ight phase 

"Normal". Here you set you values phase-specifi cally 

for the aileron differentiation, the share of the mixture 

of transverse to side, and if applicable, also a mixture 

of altitude to transverse. (The latter increases the agility 

over the transverse axis when "Turning".)

Aile.diff.

Brake sttings

AI 55%

WING MIXERS

EL FL 0% 0%

–––

–––

RU

Thermal

33%

Notice:

The list of displayed options depends on the number of 

servos entered in the "Ailerons/fl aps" line in the "Model 

type" menu.

Now switch to the submenu ...
Detail program description - Control adjust 259

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red

+30%

+33%

0% 0%

0% 0%

WK WK2

Normal

... and enter how wide the ailerons should be raised in 

the "Crow" line.

With "D.red" (differentiation reduction), you should enter 

the value previously set in the aileron differentiation line 

in order to suppress it again while breaking.

In the "Elevat curve" submenu, enter a correction value 

for the elevator, see page 162.

Notice:

The "Brake settings" submenu of the "Wing mixers" 

menu is switched "off" if "yes" is entered for the current 

fl ight phase in the "Model type" menu, page 82 "Motor 

at C1 front/rear" and in the "Motor" column of the 

"Phase setting" menu, page 128. Change the fl ight 

phase, if applicable.
260 Detail program description - Control adjust

 Example 2 ...

Glider with four fl ap wings, two large fl aps and tow 

coupling

AI

FL

FL

AI

EL

RU

The following example is based on the assumption that 

you have already mechanically preadjusted the model 

and you have already ensured the correct defl ection of 

all rudders or checked this again in the scope of this 

programming and made adjustments, if applicable, 

through servo switching at the receiver and/or through 

the "Servo setting" menu. 

This programming example is based on an assignment 

of the receiver connections in accordance with the 

following diagram:

Receiver power supply

Free or aux. function

Free or aux. function

Aileron or left aileron

Elevator or left rudder / elevator

2nd airbrake servo or 2nd elevator or aux. funct

Receiver power supply

1st airbrake servo

Right aileron

Flap or left flap

Right flap

Aero-tow release or free or aux. function

Free or aux. function

Rudder or right rudder / elevator

Begin with the new programming of the model in a free 

model memory location. 

In the menu "Base setup model", connect your receiver 

to the transmitter, enter a model name and select or 

check, if applicable, the stick mode. Later, before the 

fl ight operation, also activate the range test in this menu.

In the menu ...

"Model type" (page 82)

... leave "Motor to C1" at "None" and the tail type at 

"Normal". In the "Aile/fl ap" line, on the other hand, set "2 

AIL 2 FL".

In the "Brake" line, program or leave "In1", because the 

brake and spoiler fl ap servos connected to 1 + 8 should 

be activated later with the corresponding C1 joystick as 

the control:

Tail type

Motor at C1

Normal

None

Aile/flaps 2AIL2FL

M O D E L T Y P E

Brake Off In 1 +90%

STO SEL

The setting in the "Brake offset" value fi eld defi nes 

the neutral position of all mixers of the "Brake settings 

submenu of the "Wing mixers" menu. Place this neutral 

point at approx. +90%, insofar as the brake fl aps should 

be retracted in the front position of the C1 joystick. The 

remaining path between +90 % and the full throw of 

the joysticks, +100 %, is then assigned as idle travel. 

This assures that the rudders or fl aps addressed by 

the mixers of "Brake settings" remain in their "Normal" 

position, even with slight deviations from the limit 

position of the C1 control. At the same time, the effective 

control path is automatically spread to 100 %.

In the menu ...

"Control adjust" (page 96 )

... assign a switch to Input 9, for example, for the 

operation of the tow coupling. In order for this switch 

to work independently of the fl ight phase, leave the 

standard default "GL" in the "Type" column of this input. 

With "– Travel +" you can adjust the control travel for the 

switching of the switch:

Input 6

offset

0%

0%

0%

–––

0%

Input 7

Input 8

Input 9

–––

–––

GL

GL

GL

GL

typ

9

By simultaneously pressing the keys  of the left 

touch pad, the setting in the "Servo display" can be 

checked.

Since the C1 control should actuate Servo 8 

simultaneously with Servo 1, establish this link through 

the menu "Control adjust".

For this reason, also switch to the line before and assign 

"Control 1" to Input 8.

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8

–––

–––

GL

GL

GL

GL

typ

Ct1

However, please note in this connection, that a nonlinear control curve programmed in the "Channel 1 

 Use of fl ight phases
Detail program description - Control adjust 261

curve" menu has as little effect on this input as brake 

offset set to less than 100 %, which you can check very 

easily in the "Servo display" menu. You can reach this 

from nearly every menu position by simultaneously 

pressing the keys  of the left touch pad:

The travel and, if applicable, the directions of rotation 

of the spoiler servos 1 and the second spoiler servo 

connected to Output 8 can be adjusted in the menu ...

Servo adjustment (page 90)

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

... 

In the Multi-fl ap menu of the ...

"Wing mixers" menu (beginning on page 146)

... you now enter the fi rst mixer values for the four wing 

fl aps; for example:

fl.pos 0%

AILE

Diff.

Ail-tr

AI +100%

+100%

+50%

0%

FLAP

Diff.

+66%

+66%

+33%

fl.pos

Ail-tr

AI

Notice:

The parameter values shown here are model-dependent 

and must be determined by test fl ights.

In the ...

AI line you defi ne the percentage with which 

the two fl ap pairs "AI and "FL" should follow 

the aileron control. Also check whether the 

ailerons are defl ected in the right direction 

during the adjustment of the parameter 

values.

 The adjustment range from -150 % ... 

+150 % enables the correct throw direction 

adjustment regardless of the direction of 

rotation of the servos.

Ail-tr Here you determine the percentage with 

which the aileron trimming should affect the 

AI and FL.

Diff. Here you specify the differentiation of the 

aileron control on the AI and FL fl aps. For 

the signifi cance of the differentiation, see 

page 148.

 The adjustment range from -100 % ... 

+150 % enables the correct differentiation 

direction adjustment regardless of the 

direction of rotation of the aileron and fl ap 

servos.

fl .pos. In this line you set the fl ight-phase specifi c 

fl ap positions for all fl aps available on the 

respective model. In the process, you can 

determine the positions the fl aps assume for 

each fl ight phase.

Notice:

The values appearing in this line are based 

on the same data set as in the comparable 

position in the "Phase trim" menu, which 

is why changes always take effect in both 

directions.

FL Since all inputs in the "Control adjust" 

menu are set to "free" by default, neither the 

ailerons nor the fl aps can be actuated in this 

standard setting. In this respect, you also 

leave the default entry here.

 However, if you would like to be able to 

vary the fl ap positions with a switch or 

proportional rotary control by the position 

specifi ed in the "fl .pos." line, assign the 

desired control to Input 6 in the "Control 

adjust" menu and set the desired reaction to 

the movement of the control selected for this 

purpose over the percentage in this lane.

ELFL This mixer incorporates the ailerons (AI) and 

fl aps (FL) with elevator actuation.

 The mixing direction is to be selected so that 

all fl aps are defl ected downward with the 

elevator pulled up and defl ected upward with 

the elevator pushed down (= hydroplane). 

The mixing proportion is normally in the low 

double-digit range.

Now switch to the "Brake settings" within the "Wing 
262 Detail program description - Control adjust

mixers" menu ...

Elevat curve

BRAKE SETTINGS

QR

Crow

D.red

+44%

+77%

+66% 0%

+55% 0%

WK WK2

Notice:

The "Brake settings" menu is switched "off" if "yes" 

is entered for the currently active fl ight phase in the 

"Model type" menu, page 82, "Motor to C1 front/rear" 

and in the "Motor" column of the "Phase setting" menu, 

page 128. If applicable, switch to the fl ight phase

Crow Further above we designated the C1 joystick 

for the brake fl ap control.

 In this line you determine the share with 

which the AI and FL should be included 

on actuation of C1 in the manner that both 

ailerons are defl ected "slightly" upward and 

both fl aps are defl ected as far downward as 

possible.

 By simultaneously pressing the keys  of 

the left touch pad, you switch to the "Servo 

display" menu so that you can observe 

the servo movement and, in particular, that 

there is no infl uence on the fl aps above the 

adjusted brake offset, e.g. +90 %, up to the 

throw limit of the controller C1; see above 

("Idle travel" of the C1 joystick).

D.red In the line "Differentiation reduction" you 

should enter the value previously set in 

the ailerons differentiation line in order to 

suppress it again during braking.

Elevat curve In this line you set another correction 

value for the elevator, see page 162.

Insofar as necessary, check and adjust all fl ap throws, 

the servo center, the servo travel and the travel limitation 

through the menu "Servo adjustment".

It may also be time to start the initial fl ight testing, 

insofar as all global settings - that is to say, all fl ightphase independent settings - are completed. 

Two additional fl ight phases should be set up in 

the following, each of which requires a somewhat 

different fl ap position.

Therefore, switch to the menu ...

"Phase setting" (page 128)

... and activate the assignment of phase names in the 

"Name" column by briefl y pressing the central SET key 

of the right touch pad:

Pha1

Pha2

Pha3

Name ph.Tim.

Pha4

Pha5

normal

Start

Strecke

–

–

–

–



Now give Phase 1 - the "Normal phase" - that is also 

the phase which includes the previous settings, the 

name "Normal", which you select with the arrow keys.

Phase 2 receives the name "Thermal" and Phase 3 

receives the name "Speed". Now conclude your entry by 

briefl y pressing the ESC key of the left touch pad or the 

SET key of the right touch pad:

Pha1

Pha2

Pha3

Name ph.Tim.

Pha4

Pha5

Normal

Thermal

Speed

–

–

–

–



Now move the marking frame over the column "ph.Tim." 

to the right to the column "Sw.time" and set a "switching 

time" from any other phase to the respective phase in 

order to avoid an abrupt phase change ; in other words 

erratic changes of fl ap positions. Now try out different 

switching times. In this example we have specifi ed 1 s in 

each case:

Pha1

Pha2

Pha3

Name Sw.time

Pha4

Pha5



+

+

Normal

Thermal

Speed

–

–

1.0s

1.0s

1.0s

0.1s

0.1s

Now assign the corresponding switches for these fl ight 

phases in the menu ...

"Phase assignment" (page 134)

... with which you can switch between the three phases.

Since no special priority is necessary, assign the switch 

"C", for example, in the display and select one of the two 

limit positions of one of the two three-stage switches, 

CTRL 9 or 10 as the switch. Then move the selected 

switch back to the center position, activate the switch 

assignment under "D" and move the selected threestage switch from its center position to the other limit 

position in order to: 
Detail program description - Control adjust 263

PHASE ASSIGNMENT

A B C D E F 

1 Normal

2 6 7

prior combi

After the switch assignment is complete, use the arrow 

keys to switch to the bottom right and activate the 

assignment of phase names by briefl y pressing the 

central SET key of the right touch pad.

Now close "SW 7" by moving the selected three-stage 

switch upward.

Assign the name "<2 Thermal>" to this switch position 

and leave the name "<1 Normal>" in the "OFF position" 

of this switch.

PHASE ASSIGNMENT

A B C D E F 

2 6 7

prior combi

2 Thermal

PHASE ASSIGNMENT

A B C D E F 

2 6 7

prior combi

1 Normal

Then move the three-stage switch down toward "SW 

6" and assign the name "<3 Speed>" to this switch 

position:

PHASE ASSIGNMENT

A B C D E F 

2 6 7

prior combi

3 Speed

The phase names selected in the programming are now 

shown, depending on the switch status, in all fl ightphase dependent menus, see the table on page 268.

Since we have already made some settings in fl ightphase dependent menus, such as in the "Wing mixers"

menu, we will now copy these settings to the "Thermal" 

fl ight phase. For this purpose, open the menu ...

"Copy / Erase" (page 64)

... and switch to the "Copy fl ight phase" line:

=>

=>

=>

=>

Copy flight phase =>

Erase model

Copy model–>model

Export to SD

Import from SD

The maximum seven fl ight phases are listed in "Copy 

from phase":

1. "1 Normal". Select the fl ight phase to be copied, 

7

Copy from phase:

3

5 =>

=>

2

4

6

1 Normal Thermal

Speed

2. By briefl y pressing the central SET key of the right 

touch pad, switch the window to the entry of the 

target memory "Copy to phase".

3. Select phase "2 Thermal" as the target:

7

Copy to phase:

3

5 =>

=>

4

6

1 Normal

Speed

2 Thermal

4. briefl y pressing the central Confi rm the selection by 

SET key of the right touch pad. 

5. A security query follows, who should be confi rmed 

with "Yes":

Phase to:

to be copied?

NO YES

1 Normal 2 Thermal

6. Then repeat the process with fl ight phase "3 Speed".

Now we will program the required settings in the 

fl ight phase "Thermal" as an example.

In order to also be able to vary the camper changing fl ap 

position in the "Thermal" phase, in the menu ...

"Control adjust" (page 96)

... you assign an operating element to Input 6 – as 

described on page 96 .

If you assign one of the two proportional rotary controls 

to this input, independent of the fl ight phase if applicable 

(CTRL 7 in the example, the ailerons (2 + 5) and camber 
264 Detail program description - Control adjust

changing fl aps (6 + 7) are moved continuously with a 

mixer proportion to be set in the "Wing mixers menu.

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

–––

Ct7

Normal

If you assign the still free second three-stage switch to 

Input 6 instead, you can call three different FL positions 

of the ailerons (AIL) and camber changing fl aps (FL) as 

well as three elevator positions (Elev) in the "Thermal" 

fl ight phase, see the following page. (These three switch 

positions correspond to the center position and the two 

limit positions of the previously mentioned proportional 

rotary control.)

Notice:

The FL and AIL fl ap positions in the two limit switch 

positions or in the switch center depend on the value set 

in the column "- Travel +" as well as the offset value and 

the mixer proportion set in the "Multi-fl ap menu" of the 

"Wing mixers" menu, see further below.

We will leave the (control) "- Travel +" at the standard 

settings of symmetric + 100 % and the offset value at 

0 %. Specifying a symmetric or asymmetric time for 

smooth switching between the three switch positions - in 

the example "1.0 s 1.0 s" - in the column "- Time +" is 

recommended:

Input 5

– time +

0.0

0.0

0.0

Input 6

Input 7

Input 8

0.0

0.0

0.0

Normal

1.0 1.0

In the "Multi-fl ap menu" of the ...

"Wing mixers" menu (beginning on page 146)

... change only the values for "FL-pos" and "FL" in 

the "Thermal" fl ight phase:

FL-pos Here you position the AIL and FL in the 

"Thermal" fl ight phase in case the assigned 

control (proportional rotary control or threestage switch) is in its neutral or center 

position in the fl ight.

FL In this line you specify the percentage at 

which the aileron and camber changing 

fl ap servos should be moved as camber 

changing fl aps with the selected control (see 

above) or with the three-stage switch:

–9%

+10%

0% 0%

+10%

AILE

Thermal

+55%

+100%

+100%

FL

fl.pos

EL FL

Diff.

Ail-tr

AI

–14%

+15%

0% 0%

+15%

FLAP

Thermal

+33%

+60%

+60%

FL

fl.pos

EL FL

Diff.

Ail-tr

AI

Simultaneously pressing the key combination  or 

 of the right touch pad (CLEAR) resets changed 

values back to the standard settings.

Notice:

Due to the improved lift distribution, the degree of 

mixture should be set so that the camber changing fl aps 

are slightly "lower" than the ailerons.

By simultaneously pressing the keys  of the left 

touch pad, you can check the reaction of the AIL and FL 

servos with actuation of the selected camber changing 

fl ap servo in the "Servo display". (Push the C1 joystick 

to the front position so that the "AIL" and "FL" fl ap 

positions can be better followed on actuation of the 

corresponding control.) 

Attention:

With actuation of the ailerons, the bars of the "Servo 

display" move in the same way and the opposite 

way with the actuation of the camber changing 

fl aps:

• In the control center position, only 

the – example – "FL-pos." setting of +10 % for the AIL 

and +15 % for the FL work.

• In the one limit position of the control, AIL and FL are 

back in their neutral position, because the degree 
Detail program description - Control adjust 265

of mixture specifi ed for the example compensates 

directly for the FL-pos. setting, whereas ...

• ... in the other limit position, AIL and FL reach the 

maximum downward offset prescribed by the mixer 

percentage.

In order to set a – corrective – admix for the elevator, exit 

the "Multi-fl ap menu" and return to the base screen of 

the "Wing mixers" menu:

Brake settings

AI 0%

WING MIXERS

FL EL +5% +5%

–––

–––

RU

Multi-flap menu

Thermal

In the two limit positions of the three-stage switch the 

elevator is moved symmetrically in this example with 

+5 % (true to side). If, on the other hand, you use a 

proportional rotary control, the elevator is defl ected 

according to the degree for the control position.

Then make the settings for the "Speed" fl ight phase in 

the same manner.

Notice:

• The digital trimming of transverse, altitude and side 

work independently of these settings – depending on 

the setting selected in the "Joystick setting" menu, 

page 92 – "Global" or for each "Phase".

• All setting values are model-dependent. Carry out 

the settings on your fi nished model and/or during the 

fl ight.
266 Detail program description - Control adjust

 Control of temporal processes

using time delay and curve mixers

A useful, but less known capability of the mx-20

HoTT software is the ability to activate nearly any servo 

movements with a maximum duration of 9.9 seconds 

using a switch.

The programming for this should be shown on the 

basis of some examples in the following. Additional 

applications can certainly be found once you become 

familiar with these capabilities.

The programming is begin in the menu ...

"Control adjust" (page 96)

... and in order to be able to approach any point of 

the control curve during the programming, fi rst assign 

one of the proportional rotary controls to the desired 

control channel – in this example CTRL 8 to the Input 

9. However, leave the standard default "GL" in the 

"Type" column so that this setting is effective for all 

fl ight phases analogously to the free mixers to be 

programmed in the following.

The input of a time delay in the "- Time +" column should 

also be dispensed with initially:

Input 6

offset

0%

0%

0%

–––

0%

Input 7

Input 8

Input 9

–––

–––

GL

GL

GL

GL

typ

Ct8

Then in the menu ...

"Only mix channel" (page 193)

... of the selected control channel, "9" in this case, is set 

to "Only MIX":

MIX ONLY CHANNEL

only

normal

789 10 11 12

It is mandatory that this is set to "Only MIX", because 

the control curves of the curve mixers described in the 

following example only function on the output of the 

same channel as desired if there is no direct connection 

between the control and output! Only then can the linear 

control signal be manipulated almost arbitrarily around a 

curve mixer and to the appropriate output.

Therefore, in the next step, switch to the menu ...

"Free mixers" (page 181)

... and program a curve mixer for the same channel, 

e.g. from "9" to "9":

ty fr to

M8

C9

C10

?? ??

 9 9

C11

C12

?? ??

?? ??

?? ??

On this second screen the desired path of the control 

curve is then set, whereby the following examples 

should only be "food for thought" for the design of your 

own control curves.

For example, the control curve could be for ...

... delayed lighting of a headlight after the beginning 

of the extension of the landing gear:

+50%

–100%

Input

Output

Point 1

C.MIX 9

normal

Curve off

9 9

–100%

... the control of a landing gear fl ap which closes 

again after the landing gear is extended:

–100%

–100%

Input

Output

Point L

C.MIX 9

normal

Curve off

9 9

–100%

... a smooth motor start-up or the extension of a 

self-launch ...

–100%

–100%

Input

Output

Point L

C.MIX 9

normal

Curve

9 9

–100%

on
Detail program description - Control adjust 267

... triggered by the same switch, but with a delayed 

startup of the drive motor connected to Output 10:

–100%

–100%

Input

Output

Point L

C.MIX10

normal

Curve

9 10

–100%

on

The function you programmed functions as desired 

according to these suggestions – which you can verify 

at any time after switching to the "Servo display" by 

simultaneously pressing the keys  of the left touch 

pad – then to, complete the programming, an arbitrary 

switch, such as "SW 8" is assigned in the menu ...

"Control adjust" (page 96)

... to the control channel used instead of the selected 

proportional rotary control – in in these examples 

"CTRL 8" to channel "9" – and the desired symmetric 

or asymmetric time span is set in the "- Time +" column 

for the amount of time in which the function should 

ultimately take place:

Input 6

offset

0%

0%

0%

–––

0%

Input 7

Input 8

Input 9

–––

–––

GL

GL

GL

GL

typ

8

Input 9

– time +

9.9

0.0

0.0

0.0

Input10

Input11

Input12

9.9

0.0

0.0

0.0

Notice:

In the course of the switch assignment, always bear in 

mind that you can also trigger multiple functions with 

one switch! For example , with the same switch a landing 

gear connected to Output 6 can be started and, as 

shown here as an example, the time-controlled landing 

gear fl aps connected to Output 9 and/or the headlight, 

etc.
268 Detail program description - Control adjust

 Eight-fl ap wing

By standard the mx-20 HoTT supports the 

comfortable control of up to eight servos for the aileron/

camber changing fl ap functions.

In the following we will consider a model without motor 

drive and without spoilers in the wings. The example 

is also based on the assumption that you have already 

mechanically preadjusted the model and you have 

already ensured the correct defl ection of all rudders or 

checked this again in the scope of this programming 

and made adjustments, if applicable, through servo 

switching at the receiver and/or through the "Servo 

adjustment" menu.

The servos should be connected to a suitable receiver 

as follows: 

2 11 6 7 12 5

3

4

9 10

Rudder Receiver output

Aileron 2 + 5

Aileron 2 11 + 12

Camber changing fl aps 

(exterior) 6 + 7

Camber changing fl aps 2 

(interior) 9 + 10

Elevator 3

Rudder 4

For the control of all fl aps, up to two additional 

proportional rotary controls are required in addition to 

the two joysticks or, alternatively up to two two-stage 

switches (SW).

In order to be able to control all servos, fi rst switch to the 

menu ...

"Model type" (page 82)

... and select "4AIL 4FL" in the "Ailerons/fl aps" line.

Tail type

Motor at C1

Normal

None

Aile/flaps 4AIL4FL

M O D E L T Y P E

Brake Off In 1 +100%

SEL

In order to also be able to actuate the camber changing 

fl ap servos 6 + 7 (FL) and 9 + 10 (FL2), if applicable, in 

the Multi-fl ap menu of the menu ...

"Wing mixers" (beginning on page 146)

... set the corresponding values for the aileron control of 

the two camber changing fl ap pairs in the line "AIL" 

and in the line "Ail-tr." for the adoption of the aileron 

trimming:

FL

0%

+100%

fl.pos

EL FL 0% 0%

+100%

FLAP

Normal

Diff. 0%

Ail-tr

AI +77%

+77%

0%

+100%

0% 0%

+100%

FLAP2

0%

+55%

+55%

FL

fl.pos

EL FL

Normal

Diff.

Ail-tr

AI

You can check the previous settings in the "Servo 

display" menu, which you can reach from nearly any 

menu position by simultaneously pressing the keys 

of the left touch pad: 

• The servos 6 + 7, 9 + 10 and 11 + 12 now move for 

the aileron control exactly like the servos 2 + 5. The 

aileron trimming lever also affects all these servos.

• The C1 joystick only actuates the servo connected to 

receiver output 1.

Attention:

With aileron actuation the bars of the "Servo 

display" move in the same manner and in the 

opposite manner with camber changing fl ap 

actuation.

The necessary fi ne-tuning of the servos is carried out in 

the ...

"Servo adjustment" menu (page 90),

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5
Detail program description - Control adjust 269

... if necessary.

In doing so, the basic programming of the eight-fl ap 

wing is completed.

Camber changing fl ap positioning and fl ight changes

First program two or more fl ight phases in the "Phase 

setting" and "Phase assignment" menus. On this 

occasion, also change the standard default "Global" 

to "Phase" in the "Joystick setting", page 92 for the 

effect of the digital trimming, if applicable, on your 

individual requirements. 

An example of fl ight phase programming can be found 

on page 256.

One camber changing fl ap setting per fl ight phase

If one camber changing fl ap position per fl ight phase is 

suffi cient for you, then in the Multi-fl ap menu" of the ...

"Wing mixers" menu (beginning on page 146)

... in the line "FL-pos" adjust the camber changing fl ap 

position(s) of the servo pair "AIL" (2 + 5), "AIL2" (11 + 

12), "FL" (6 + 7) and "FL2" (9 + 10) to your preferences 

in each of the programmed fl ight phases:

–5%

+100%

0% 0%

+100%

AILE

+33%

+100%

+100%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

–7%

+100%

0% 0%

+100%

AILE2

+33%

+90%

+90%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

–9%

+100%

0% 0%

+100%

FLAP

0%

+77%

+77%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

–12%

+100%

0% 0%

+100%

FLAP2

0%

+55%

+55%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

Notice:

Whether positive or negative values must be set in the 

"FL-pos." line depends on the installation of the servos, 

among other things.

Alternatively, if you would like

to set variable camber changing fl ap positions for 

each fl ight phase with a proportional rotary control,

... you can additionally vary the basic settings of all 

eight fl aps with a single control specifi c to each fl ight 

phase.

For this purpose, in the menu ...

"Control adjust" (page 96)

... the inputs 5, 6 and 11 are assigned for each fl ight 

phase to the same respective control, for example the 

proportional rotary control CTRL 7, and in parallel, the 

travel is reduced to approximately 50 % or even less 

so that the fl aps can be trimmed with the appropriate 

fi ne-tuning. With travel settings differing from one 

another, you can also attune the throws of the individual 

fl ap pairs to one another specifi c to the fl ight phase in 

a menu. For this purpose, you only have to switch the 

corresponding inputs from the standard default "GL" 

(global) to "PH" (phase):

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

–––

–––

PH

GL

PH

GL

typ

Normal

Input 9

offset

0%

0%

0%

–––

0%

Input10

Input11

Input12 –––

–––

–––

GL

PH

GL

GL

typ

Normal
270 Detail program description - Control adjust

Input 5

– travel +

+25%

+25%

+100%

+100%

Input 6

Input 7

Input 8

+25%

+25%

+100%

+100%

Thermal

Input 9

– travel +

+100%

+100%

+25%

+100%

Input10

Input11

Input12

+100%

+100%

+25%

+100%

Thermal

Notice:

With the use of a switch, set the respective "Deviation" 

of the offset point symmetrically or asymmetrically in the 

"- Travel +" column.

Elevator compensator with actuation of the camber 

changing fl aps

If it should become evident in the fl ight that a correction 

of the elevator is necessary after setting the fl aps, this 

correction can be made in the ...

"Wing mixers" menu (beginning on page 146)

Brake settings

AI 0%

WING MIXERS

FL EL 0% 0%

–––

–––

RU

Multi-flap menu

Thermal

. For this purpose, select the line "FL  Elev" and enter 

an appropriate value independent of the fl ight phase. 

If you have assigned the same control to the inputs 

5, 6 and 11 – as specifi ed above – all eight fl aps move 

simultaneously while the elevator follows the set degree 

of mixture.

Camber changing fl ap movement on elevator actuation

Camber changing fl ap movement on elevator 

actuation – normally only used in "High gear" to increase 

the agility over the transverse axis – is also carried out in 

the "Multi-fl ap menu" of the...

"Wing mixers" menu (beginning on page 146)

. Enter the desired fl ight-phase dependent values in the 

line "Elev->FL":

–5%

+33%

0% 0%

+33%

AILE

+33%

+100%

+100%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

–7%

+33%

0% 0%

+33%

AILE2

+33%

+90%

+90%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

–9%

+100%

0% 0%

+100%

FLAP

0%

+77%

+77%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

–12%

+100%

0% 0%

+100%

FLAP2

0%

+55%

+55%

FL

fl.pos

EL FL

Thermal

Diff.

Ail-tr

AI

In addition to the two camber changing fl ap pairs 

(servos 6 + 7 and 9 + 10), the two aileron pairs (servos 

2 + 5 and 11 + 12) are now tracked with the degree 

of mixture corresponding to the camber changing 

fl aps - normally opposite the elevator.

Brake settings

Notice:

The "Brake settings" menu is switched "off" if "yes" 

is entered for the currently active fl ight phase in the 

"Model type" menu, page 82, "Motor to C1 front/rear" 

and in the "Motor" column of the "Phase setting" menu, 

page 128 . Change the fl ight phase, if applicable.

In the "Brake settings" submenu, which is also fl ightphase specifi c, of the "Wing mixers" menu, you can 

make the settings so that the aileron pairs 2 + 5 and 
Detail program description - Control adjust 271

11 + 12 extend upward and the camber changing fl ap 

pairs "FL" (6 + 7) and "FL2" (9 + 10) extend downward, 

whereas the elevator is trimmed in parallel to this, see 

page 162.

In order for the brake system to react to the C1 joystick 

as desired, however, the mixer neutral point (offset) of 

the brake system must be adjusted accordingly. This 

takes place in the menu ...

"Model type" (page 82)

After selection of the line "Brake Off." the C1 joystick is 

moved to the position from which the mixer for the brake 

system should be set – normally just before the limit 

position – and after selection of the appropriate value 

fi eld, the set point is defi ned by briefl y pressing the 

central SET key of the right touch pad.

If the C1 joystick is not moved over this point toward 

the pilot, all mixers of the brake system are carried 

along according to their respective degree of mixing. 

Below this point the mixer remains inactive, whereas the 

selection of "dead travel" is possible.

If the model has additional brake fl aps or spoilers and 

your receiver has another free Output 1, you can also 

control this through the C1 joystick by connecting the 

spoiler servo to receiver Output 1. 

However, if you control the left and right spoiler each 

with its own servo, and not together, the receiver Output 

8 is still available for the connection of the second 

spoiler servo. In this case, program the connection to 

the second spoiler servo as described in the section 

"Servos running in parallel" on page 254.

Reduction of the aileron and camber changing fl ap 

differentiation

For the improvement of the aileron effect in the crow 

position, you should automatically suppress any 

programmed aileron differentiation. 

For this purpose, use the "Differentiation reduction" 

in the "Brake settings" of the "Wing mixers" menu, 

which continuously reduces the degree of the aileron 

differentiation to a variable extent when you move the 

rudders to the crow position with the C1 joystick. For this 

purpose, see page 162.

.
272 Detail program description - Control adjust

Of course, the general comments regarding the 

installation and the adjustment of the RC system to a 

model at the beginning of the wing model programming 

on page 236 also applies for delta and fl ying wing 

models! Similarly, the comments for test fl ying and fi netuning the settings to the programming of fl ight phases 

also apply.

left

right

Delta and fl ying wing models differ signifi cantly from a 

"normal" fl ight model due to their unique characteristic 

shape and geometry. The differences in the servo 

arrangement, on the other hand, are more subtle. For 

example, with "classic" delta/fl ying wing models, only 

two rudders are normally provided. They are responsible 

for both "transverse" and "height/depth", like the side 

rudder/elevator function on a V-tail unit.

With more elaborate designs, on the other hand, it 

may be the case that one (or two) interior rudders 

have only an elevator function and the exterior ailerons 

only support the height/depth function, under certain 

circumstances. Even with a four or six-fl ap wing the 

use of camber changing fl ap functions and/or even a 

crow system is now entirely possible. In all these cases, 

however, the following assignment of the receiver 

outputs should be used, see also page 57. Unneeded 

outputs a simply left free: 

Receiver power supply

Free or aux. function

Free or aux. function

Right elevon

Right elevon

Free or aux. function

Receiver power supply

Airbrake or throttle servo

or speed controller (electric motor)

Free or aux. function

Free or left flap / elevator

Free or right flap / elevator

Free or aux. function or left flap 2 / elevato

Free or aux. function or right flap 2 / elevat

Free or rudder

According to the assignment of the receiver outputs, in 

the menu ... 

"Model type" (page 82)

None

2AIL

+100% In 1

SEL

Tail type Delta/fl

Motor at C1

Aile/flaps

M O D E L T Y P E

Brake Off

... the necessary settings are made:

"Motor at C1" "none" or "Throttle min front/rear"

"Tail type" "Delta/fl "

"Aile/FL" "2AIL" (appears automatically).

 Insofar as necessary, expand the 

default "2AIL" with 1, 2 or 4 camber 

changing fl aps ("1FL", "2FL" or "4FL").

"Brake" remains or is only of interest with a 

delta or fl ying wing aircraft of the type 

"2 AIL 1/2/4 FL". In this case, see 

under "Brake offset" on page 83.

 Delta and fl ying wing models

These settings specifying the model type affect the 

available "Wing mixers" fi rst and foremost. Therefore, 

the options are discussed separately for two-fl ap and 

multi-fl ap models in the following: 

Delta/fl ying wing of the type: "2AIL"

+100%

SEL

Delta/fl

2AIL

None

In 1

Tail type

Motor at C1

Aile/flaps

M O D E L T Y P E

Brake Off

In keeping the standard default "2AIL" in the "Aile./

FL" line, the elevator and aileron control, including the 

trimming function, are only mixed automatically on the 

software side. On the transmitter side, however, you can 

infl uence the effect of the elevator and aileron joystick in 

the "Dual Rate / Expo" menu, page 108.

Settings in the menu ...

"Wing mixers" (beginning on page 146)

... are, if need be, advantageous with the "AIL  FL" 

mixers and are "played' with a great deal of "feel" for the 

fl ying behavior with minor differentiation values. 

Aile.diff

Brake settings

+10%

AI +50%

WING MIXERS

HR WK 0% 0%

–––

–––

RU

normal

Due to the specifi c idiosyncrasies of this model type, 

additional settings lead to incompensable moments.
Detail program description - Control adjust 273

FL

0%

0%

fl.pos

EL FL 0% 0%

0%

AILE

normal

Diff. 0%

0%

+100%

0% 0%

+100%

FLAP

normal

0%

FL

fl.pos

EL FL

Diff.

0%

+100%

0% 0%

+100%

FLAP2

normal

0%

FL

fl.pos

EL FL

Diff.

Notice:

Contrary to the separately set aileron trimming, see 

below, the trimming is transferred proportionally to the 

set mixer value with the mixer "Elev  FL".

The following settings are model-specifi c and may 

not be adopted without checking that they are 

correct!

In the top line of this "Multi-fl ap menu", analogously to 

"normal" four or six fl ap wings, the effect of the aileron 

joystick on the aileron, camber changing fl ap and, if 

applicable on FL2 is set. In the line "Ail-tr." below this, 

on the other hand, the infl uence of the aileron trimming

Delta/fl ying wing of the type: "2 AIL 1 / 2 / 4 FL"

Tail type

Motor at C1 None

Aile/flaps

M O D E L T Y PE

Brake Off In 1 +100%

SEL

Delta/fl

2AIL4FL

With delta/fl ying wing constructions with more than 

two fl aps, more moments can be compensated for. For 

example , the "lifting" moment caused by the raising of 

the ailerons (= elevator effect) can be compensated for 

with camber changing fl aps lowered correspondingly 

wide ( = hydroplane effect).

If you decide in favor of this model type and have 

assigned the receiver outputs in accordance with the 

connection plan shown above, the aileron function of 

the two (exterior) aileron servos will function correctly 

immediately, but not the elevator function of the two 

aileron servos and, if applicable, the (interior) camber 

changing fl aps. 

This is achieved with the specifi cation of "2AIL 1/2/4 

FL", if the effect of the elevator control, in the "Multi-fl ap 

menu" of the ...

"Wing mixer" menu (beginning on page 146)

... is set appropriately in the "Elev  FL" line for 

aileron, camber changing fl ap and, if applicable, camber 

changing fl ap 2: 

on ailerons and camber changing fl aps.

The setting of a differentiation is rather tricker due to the 

model type and should only take place based on a feel 

for the fl ight behavior of the model.

In the line "FL", for the sake of safety, you should 

set the standard setting +100 % in the "FL" and, if 

applicable "FL2" column – as shown – to 0%:

0%

0% 0%

FLAP

normal

0%

FL 0% 0%

fl.pos

EL FL

Diff.

0%

0% 0%

FLAP2

normal

0%

FL 0% 0%

fl.pos

EL FL

Diff.

In the "Control adjust" menu, all inputs are set to "free" 

by default, but if there is ever confusion in regard to the 

assignment of a control ... this has little effect at all.

The last line, "Elev FL", has already been addressed 

earlier in this section.

In principle, the author of this manual had programmed 

a delta model years ago operated with the mc-20

and a crow system as landing assistance ... entirely 

without tilting moments through correspondingly attuned 

wing mixers "Brake  aileron" and "Brake  camber 

changing fl ap", whereby "aileron" refers to the exterior 

rudder pair and "camber changing fl ap refers to the 

interior rudder pair. 
274 Detail program description - Control adjust

In order to now achieve this with the mx-20 Hott, 

switch to the "Brake settings" of the ...

"Wing mixers" menu (beginning on page 146)

... and enter the values for the ailerons to be raised 

and the "fl aps" to be lowered in the "Crow" line so that 

the occurring moments compensate one another and 

the altitude of the model remains stable. In the process, 

however, you should leave the fl aps with enough "play" 

for the elevator function!!! Therefore, do not utilize the 

entire servo travel for the crow alone; for example:

Elevat curve

BRAKE SETTINGS

AILE

Crow

D.red

+55%

0%

–44% 0%

0% 0%

FLAP FLAP2

Normal

You can ignore all other settings in this menu.

Notice:

The "Brake settings" menu is switched "off" if "yes" 

is entered for the currently active fl ight phase in the 

"Model type" menu, page 82, "Motor to C1 front/rear" 

and in the "Motor" column of the "Phase setting" menu, 

page 128. Change the fl ight phase, if applicable.

Similarly, a modern, tapered fl ying wing air craft can 

also be operated. With some of these models there 

are also interior and exterior rudders: The prior is in 

front of the center of gravity and the latter is behind. A 

downward throw of the central rudder(s) increases the 

ascending forces and has an elevator effect. An upward 

throw has the opposite effect. On the exterior ailerons, 

on the other hand, the effect is just the opposite: A 

downward throw shows an elevator effect and vice 

versa. With appropriate adjustment of the "leading" 

mixer to the setting of curve mixers in order to achieve a 

supporting effect from the external rudder pair with only 

extreme joystick defl ection in the height/depth direction, 

"everything" is possible here. The author of this manual 

uses a curve mixer for his model, which is defi ned by a 

total of four points:

0%

0%

Input

Output

Point

C.MIX 9

normal

Curve

EL 5

0%

on

In this example the two interpolation points 1 and 2 

are each at 0 % as well as the left edge point at +60 % 

and the right edge point at -65 %. Then the curve was 

rounded by pressing the central SET key of the right 

touch pad.

In this case: Regardless of which type of servo 

arrangement was selected, any type of differentiation 

should be set with caution! On a tail-less model, 

differentiations show a single-sided height/depth 

elevator effect, so we urgently recommend beginning 

at least the initial fl ights with a setting of 0 %! Over 

the course of the further fl ight testing, under certain 

circumstances it may be advantageous to experiment 

with differentiations deviating from zero. 

With larger models, rudders in the winglets - the "ears" 

mounted on the wing ends - can be benefi cial. If these 

are controlled with two separate servos, with the use of 

one of the mixers in the menu ...

"Cross-mixer" (page 194)

... the rudder signal can be "split" very easily and even 

differentiated, whereby the second rudder servo is 

connected to one of the still free receiver outputs. For a 

model of the type "Delta/Nf", the receiver output "5" may 

still be free, and we want to use it in the following:

Typ zu Diff.

DUAL MIXER

Mixer1

Mixer2

 5 RU

Mixer3

Mixer4

?? ??

?? ??

?? ??

0%

0%

0%

+66%

In this case a differentiation is necessary, because 

the respective exterior rudder fl ies over a larger curve 

radius than the interior rudder, which is comparable to 

the wheel position of the front wheels of a car when 

traveling on curves.

Notice:

The rudder can only be differentiated as programmed 

above!

If these two rudders should also defl ect outward on the 

actuation of a brake system with the C1 joystick, this 

can be achieved, for example, by setting an additional 

mixer "C1  5" with an appropriate travel setting. Set 

the offset according to your habits to "front" (+100 %) 

or "rear" (-100 %), because the winglet rudder should 

defl ect outward proportionally on extension.

Independently of this, you should, for safety's sake, 

uncouple the "false" control function from the control 

signal to which the second servo was connected – even 

if all inputs are "free" by default in the "Control adjust" 

menu – through the fl ight-independent menu ...
Detail program description - Control adjust 275

"Only mix channel" (page 193)

... for safety's sake! Corresponding with the above 

example, therefore, the control channel 5 should be set 

to "only MIX":

MIX ONLY CHANNEL

only

normal

123 4 5 6
276 Detail program description - Control adjust

 F3A model

F3A models are a part of the group of motor-driven 

winged models. They are powered by a combustion or 

electric motor. Models with electric motors can be used 

in both the electric acrobatic class F5A and are also 

competitive in the international model acrobatic class 

F3A.

The basic comments and notices for the mechanical 

installation of a remote steering system, which was 

already referred to in the fi rst programming example on 

page 236, also applies, of course, for F3A models and 

does not need to be mentioned here again.

Faultlessly constructed F3A models exhibit a largely 

neutral fl ying behavior. Ideally, they react with a good 

nature but precisely to control movements without the 

individual fl ight axes infl uencing one another.

F3A models are controlled with ailerons, elevator 

and rudders. Normally, each aileron is actuated by a 

separate servo. There is also the regulation of the drive 

output of the motor (throttle function) and a retractable 

landing gear in many cases. The assignment of the 

channels 1 to 5, therefore, do not differ from the 

previously described winged models. 

The additional "Retractable landing gear" function is 

to be provided on one of the auxiliary channels 6 to 

9. It is best to actuate the landing gear with a switch 

without center position. In addition, another mix offset 

for the carburetor can – if necessary – be provided. You 

normally use one of the two proportional rotary controls 

on the transmitter, which actuates one of the unassigned 

auxiliary channels.

Receiver power supply

Free or aux. function

Free or aux. function

Rudder

Aileron or left aileron

Elevator or 1st elevator

Free or 2nd elevator or aux. function

Receiver power supply

Airbrake or throttle servo

or speed controller (electric motor)

Right aileron

Free or aux. function (retracts)

Free or aux. function (mixture)

Free or aux. function

Free or aux. function

With the assignment of auxiliary channels at the 

transmitter, we recommend making sure that the 

operating elements required for this are easily 

within reach, because during fl ight – especially in 

competition – you have "very little time" to release the 

joystick.

Programming

Since the basic programming of the transmitter was 

already described in detail on pages 236 ... 243, only 

F3A-specifi c tips are added here.

In the menu ...

"Servo adjustment" (page 90)

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

... the settings for the servos are carried out. Experience 

has shown that working with at least 100 % servo 

throw is benefi cial, because the control precision 

is signifi cantly better if greater servo travel is used. 

This should already be taken into account during the 

construction of the model in the design of the rudder 

linkages. Check the servo's direction of rotation. The 

servo center should be adjusted mechanically, insofar as 

possible. 

Any corrections can be made on the software side in the 

third column during the initial test fl ights. 

Through the menu ...

"Model type" (page 82 )

... the idle trim is activated for Channel 1 (normally 

"rear", because full throttle is "front"). The trimming then 

only works in the idle direction:

Tail type

Motor at C1

Normal

Aile/flaps 2AIL

M O D E L T Y P E

Brake Off In 1 +100%

SEL

back

The remaining settings are made or left as shown in the 

fi gure.
Detail program description - Control adjust 277

After test-fl ying and trimming of the model, we 

recommend reducing the trim travel for the elevator and 

ailerons The model has signifi cantly less of a reaction 

to a movement of the trim lever. "Overtrimming" can 

be avoided, because with full trim travel, under certain 

circumstances, the movement by just one trimming 

step can have too strong of an effect: Therefore, the 

model which previously pulled slightly to the left, hangs 

somewhat to the right after the trimming. For this 

purpose, switch to the menu ...

"Joystick setting" (page 92)

... and reduce the number of trimming steps accordingly 

in the "St" column:

Ch.1

Aile

Elev

Tr time +

4

2

2

0.0s

0.0s

0.0s

Rudd 0.0s

0.0s

0.0s

0.0s

0.0s

GL

GL

GL

GL

St

2

It may also be necessary to assign a corresponding 

operating element to a specifi c input for the activation 

of the retractable landing gear and the mixer movement 

through the menu ...

"Control adjust" (page 96) 

... such as one of the ON/OFF switches to the Input 6 

for the landing gear and one of the proportional rotary 

controls, e.g. CTRL 7, to the Input 7. However, since 

it involves fl ight-phase independent settings, leave the 

standard default "GL" in the "Type" column: 

+33%

+33%

+33%

Ail

Ele

Rud

EXPO

–––

–––

SEL

normal

–––

(Some experts even use up to a +60 % exponential 

degree.)

Since (some) combustion motors do not react linearly to 

movements of the throttle joystick, through the menu ...

"Channel 1 curve" (page 116)

... a "bowed" or, in other words, non-linear throttle 

curve can be set. Four-cycle motors with Roots pumps, 

in particular, such as OS Max FS 120, require a steep 

ascension of the curve in the lower speed range. 

However, the corresponding values must be adapted. 

The C1 control curve for the motor could appear as 

follows:

Input

Output

Point 1

–50%

0%

0%

C1

normal

Curve

Curve on

Only three interpolation points, "L" at -100 %, "H" at 

+100 % and "1" at -50 % give the control travel the 

rounded curve above.

Input 5

offset

0%

0%

0%

–––

0%

Input 6

Input 7

Input 8 –––

GL

GL

GL

GL

typ

Ct7

3

The control travel of the operating elements must be 

adapted and can also be reversed with a negative travel 

setting. 

Notice:

A delay time for the extension and retraction can be 

specifi ed for the retractable landing gear, which does not 

work, however, for the landing gear servo C 713 MG, 

Order No. 3887.

F3A models fl y comparatively fast and thus react 

"harshly" to the control movements of the servos. 

However, since small control movements and 

corrections are not optically perceptible, because this 

results in inevitable point deductions in competition, we 

recommend setting an exponential control characteristic 

of the joystick. For this purpose, switch to the menu ...

" Dual Rate / Expo " (page 108)

Experience has shown positive results with values of 

approx. + 30 % on the ailerons, elevator and rudders, 

which you set in the right column with the arrow keys. 

In order to be able to control the F3A model to run 

smoothly and cleanly:
278 Detail program description - Control adjust

Basic procedure:

• Move the C1 joystick and, along with it, the vertical 

line in the graphic display toward idle to -50 % control 

travel and briefl y press the central SET key of the 

right touch pad.

• In order to attain the curve shape shown, raise 

this point with the arrow keys to approx. 0 % in the 

inverse value fi eld of the "Point" line.

• Then round the characteristic curve by moving the 

marking frame up to the "Curve" line, briefl y pressing 

the central SET key of the right touch pad and then 

changing the value from "Off" to "On" with the arrow 

keys.

If additional interpolation points between the left ("L") 

and right ("H") end are necessary, repeat Steps 2 and 3 

analogously.

Since F3A models normally have two aileron servos, 

experience has shown that it is benefi cial to move 

both ailerons upward somewhat when landing. In the 

process, the model usually fl ies somewhat slower and, 

fi rst and foremost, more steadily for the landing. For this 

reason, it is necessary to program mixers through the 

menu ...

"Free mixers" (page 181)

... accordingly.

The ailerons are extended as landing assistance 

depending on the position of the throttle stick, starting 

from approximately half throttle toward idle. The 

further the joystick is moved toward idle, the more the 

ailerons defl ect upward. Just the opposite applies when 

"throttling"; the ailerons are retracted again in order to 

prevent a sudden rise of the model. 

In order to prevent the model from climbing with the 

aileron landing fl aps extended, the elevator must be 

mixed in somewhat.

For this purpose, set the two linear mixers shown in 

the following display. The activation of the mixers takes 

place with one and the same switch, such as SW 8, 

to which both mixers must be assigned with identical 

switching direction.

ty fr to

M1

M2

M3

C1 5

C1 EL

M4

M5 ?? ??

?? ??

?? ??

8

8

Then switch to the second respective display screen in 

order to adjust the respective mixing degrees. In both 

cases the mixer neutral point is at the C1 control center.

Enter 0 % above the control center after selection of the 

ASY fi eld for both mixers and below the control center 

toward idle for: 

MIX 1: -60 % ... -80 % and

MIX 2: -5 % ... -10 % .

Example L.MIX 1:

0%

0% 0%

FLAP

normal

0%

FL 0% 0%

fl.pos

EL FL

Diff.

With this, the base setup model of an F3A model is 

concluded.

Compensation of model-specifi c errors

Unfortunately, there are nearly always minor modelspecifi c "errors" through the mixers of a computer 

remote control which must be compensated for. 

However, before you begin with these settings, it should 

be ensured that the model is faultlessly constructed, 

optimally balanced over the longitudinal and transverse 

axes and the down thrust and side thrust are correct.

Infl uence of longitudinal and transverse axes by the 

rudder

The actuation of the rudder often infl uences the 

behavior of the longitudinal and transverse axes. This 

is particularly disruptive in so-called knife-edge fl ying, 

in which the lift of the model with the rudder defl ected 

should be created by the fuselage alone. In the process, 

the model can rotate and change directions as though it 

were controlled with the ailerons and elevator. Therefore, 

a correction over the transverse axis (elevator) and/

or the longitudinal axis (ailerons) must be made, if 

applicable.

This can also be carried out with the "Free mixers" 

of mx-20 HoTT. If, for example, the model rotates 

away to the right over the longitudinal axis with the 

rudder extended in knife-edge fl ying, the aileron can be 

defl ected to the left with the mixer. Changes in direction 

over the transverse axis can be performed analogously 

with a mixer on the elevator:

• Correction over the transverse axis (elevator)

L.Mix 3: "Rudd  Elev"

Asymmetric setting. The appropriate values must be 

tested in fl ight.

• Correction over the longitudinal axis (aileron)

L.Mix 4: "Rudd  AIL"
Detail program description - Control adjust 279

Asymmetric setting. The appropriate values must be 

tested in fl ight.

Relatively small mixer values are usually suffi cient 

in this case, the range lies below 10 %, but can vary 

from model to model. With the use of curve mixers, the 

mix ratios can be adapted even more precisely to the 

corresponding throw of the rudder. Again, no values are 

indicated for this, because this would be model-specifi c.

Vertical ascent and descent

Some models have a tendency to deviate from the ideal 

line in vertical ascents and descents. 

In order to compensate for this, it is necessary to have a 

center position of the elevator dependent on the throttle 

joystick position. If, for example, the model begins to 

hold off on its own in the vertical descent with a throttled 

motor, some elevator must be mixed in at this throttle 

position. 

For this purpose, program a free mixer "C1  Elev". 

The corresponding mixer values are normally under 5% 

and must also be tested in fl ight. 

Turning away over the longitudinal axis in idle

If the throttle is reduced, the model may begin to turn 

away over the longitudinal axis in idle. This can be 

counteracted with the aileron. 

However, the more elegant solution is to correct this 

effect with a free mixer "C1  Ail". 

The input values here are usually very low (approx. 3 %) 

and the settings should be made in calm weather. It 

often suffi ces to only use the mixer between half throttle 

and idle. Therefore program the mixer asymmetrically, if 

applicable.

Turning away with the ailerons/landing fl aps 

extended

If you move the ailerons upward for the landing, the 

result is often a turning away over the longitudinal axis 

due to various servo paths of the aileron servos or 

due to design precisions. Therefore, the model begins 

to automatically hang the left or right wing. This is 

also easy to compensate for with a mixer "C1  AIL" 

depending on the position of the ailerons/landing fl aps. 

The mixer must be switched on and off with the same 

switch with which you can switch the aileron/landing 

fl ap function on and off (see previous page). Therefore, 

it only works with the aileron/landing fl ap function 

activated. The appropriate value must be tested in fl ight. 

One additional comment regarding ...

"FAIL-SAFE setting"

You utilize the safety potential of this option by the 

safety potential by programming at least the motor 

throttle position for combustion models to idle and the 

motor function for electrically powered models to stop 

for a Fail-Safe case. Then, in the event of a failure, 

the model cannot become independent as easily and 

cause property damage or even personal injury. If 

you additionally program the fail-safe positions of the 

rudders to that the model fl ies in gently sinking circles 

in the event of a failure, there is a good chance that 

the model even lands relatively gently on its own in the 

event of a continuing connection failure. You also have 

suffi cient time to re-establish the connection if the entire 

2.4 GHz frequency band is temporarily disrupted. 

In the receiver's condition as supplied, however, the 

servos maintain their last validly recognized position 

("hold") in the event of a fail-safe situation. As described 

on page 196, you can defi ne a "Fail-safe position" for 

each of the individual servo outputs of your receiver 

(Fail-safe mode).

Summary

The settings described on this page are especially 

useful for the "expert" who would like to have an entirely 

neutral, precisely fl ying F3A model acrobatic model at 

his or her disposal. 

It should be mentioned this takes a lot of time, effort, 

instinct and know-how. Experts even program during 

the fl ight. To do this, however, is not suggested for an 

advanced beginner who ventures into an F3A acrobatic 

model. It would be best to turn to an experienced pilot 

and carry out the settings step by step until the model 

has the desired neutrality in its fl ight behavior. Then the 

pilot can begin to learn the not always easy to perform 

acrobatic fi gures with a model which fl ies faultlessly.
280 Detail program description - Control adjust

 Helicopter models

With this programming example, you must have already 

covered the description of the individual menus and 

you must be familiar with the use of the transmitter. 

In addition, the helicopter's mechanical construction 

should correspond exactly to the corresponding manual. 

The electronic capabilities of the transmitter should by 

no means be used to straighten out rough mechanical 

imprecision.

As the case often is in life, there are also various ways 

and possibilities of achieving a specifi c goal with the 

programming of the mx-20 HoTT. The following 

example should provide you with a clearer structure for 

logical programming. If there are multiple possibilities, 

the simplest and most clearly arranged solutions are 

recommended fi rst. In order for the helicopter to function 

faultlessly later on, you are, of course, free to try out 

other solutions which may be better for you.

The programming example is based on the clockwiserotating STARLET 50 helicopter from Graupner with 

three pivot points each offset 120° of the swashplate 

type "3sv(2 Roll)", beginner adjustment without 

increased throttle curve; without heading-lock gyro 

system and without transmitter-side gyro infl uence of the 

"normal operating mode" and without speed regulator. 

This simple program was also consciously selected to 

demonstrate that a helicopter which fl ies really well can 

also be attained with relatively little (programming) effort. 

However, we do not want to dispense entirely with the 

enhancement possibilities: Therefore, after the basic 

description, you will fi nd adjustment information for the 

gyro effect, the speed regulators and for the fl ight-phase 

programming.

Notice:

If you are not interested in the combustion helicopter 

described here, but a electric helicopter, please continue 

reading anyhow! With the exception of the omitted idle 

settings, you can practically adopt most of the settings 

described in the following unchanged.

Some basic settings of the transmitter are necessary 

with the initial commissioning. For this purpose, switch 

to the menu ...

"General settings (page 224)

Batterie type

Batterie warning

Touch Sense

Contrast

Ni-MH

Display light

Region

Voice volume

2

4.7V

0

Euro

3

unlim.

Beep volume 3

BASIC SETTINGS

Own

Stick mode 1

DSC Output PPM10

Pitch min back

Power-on beep yes

Power on warn. unlim

... and start with the entry of the "Owner name". Select 

the characters for this from an extensive list on the 

second display screen, which you can reach through the 

 symbol by briefl y pressing the central SET key of 

the right touch pad:

 !"#$%&’()+,–./012

3456789:;

Owner H-J Sandb

FGHIJKLMNOPQRSTUVWX

YZ[¥]^_`a b cdefghijk

?@ABCDE

Select the default "Stick mode" according to the criteria 

described on page 224.

The same applies for the default "DSC output".

The default "Pitch min" is based on your control habits. 

With the creation of a new model memory you can 
Detail program description - Control adjust 281

change these in the adopted defaults "Stick mode", 

"DSC output" and "Pitch front/rear" as well as within 

the respective model memory location.

The setting the "Contrast" line determines the legibility 

of the display under poor light conditions and the setting 

in the "Display light" line determines how long the 

display lighting remains illuminated after the transmitter 

is switched on or after the last key actuation.

With "Power-on beep yes/no" you determine whether 

the transmitter plays a recognition melody when 

switching on.

In the "Battery type" line you specify whether the 

transmitter is supplied with current from a "NiMH" or a 

"LiPo" battery, and in the "Battery warning" line below 

it, you determine the voltage at which the low-voltage 

warning of the transmitter should trigger. Do not enter a 

value that is too low here, so you have enough time to 

land your helicopter.

In the "Power-on warn." line you can adjust how long 

the transmitter should wait after the last actuation of 

an operating element until it alerts you that it is still 

switched on with optical and acoustic warning signals. 

With the values of the lines "Touch sense", "Voice 

volume" and "Signal volume", you can adjust the 

corresponding behavior of the transmitter to your 

requirements. And, in the event that you (would like to) 

commission your transmitter in France, the setting in the 

"Region" line is important: The legal regulations of this 

country require the selection of "France" instead of the 

default setting "Euro".

If these settings are activated, it continues with the 

menu ...

"Model select" (page 63)

Select a free storage location with the arrow keys ...

03

04

05

02  free 

01

06

R12

 free 

 free 

 free 

 free 

...and open this by briefl y pressing the central SET

key of the right touch pad. In the subsequently opening 

display, with the key  of the left or right touch pad, 

select...

Select model typ

... the "Heli" model type. The display immediately 

switches to the base screen if you confi rm this selection 

by briefl y pressing the central SET key of the right touch 

pad. 

Notice:

• If the "Select model type" option has been opened, 

the process cannot be canceled. Even if you switch 

off the transmitter, this selection must be made! In 

any case, you can undo this by subsequently deleting 

the respective model memory.

• If the "Throttle too high" warning appears, this can 

be deleted by turning the proportional rotary control 

CTRL 6 counterclockwise until its limit.

• If battery voltage is too low, the model switchover 

cannot be made due to reasons of safety. An 

appropriate message will appear in the screen:

not possible now

voltage too low

Once this fi rst hurdle is cleared, the connection of the 

receiver built into the model at this model memory must 

be made in the menu ...

"Base setup model" (page 74 ... 80)

. For this purpose, switch to the line "RF bind":

1

n/a n/a

BD1

Starlet

BD2

E12

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

RF transmit OFF

Notice:

After confi rmation of the model selection in the base 

screen, if you confi rm the message appearing in the 

screen for a few seconds ...

BIND N/A

OK

... by pressing the SET key of the right touch pad, you 

automatically come to this line.

In the line"RF Bind." you delete the connection process 

between model memory and receiver, as described in 

detail on page 74. Otherwise, you cannot address the 

receiver.

Afterwards, using the arrow keys of the  left or right 

four-way pad, move up to the fi rst line and begin with 

the actual model programming in the "Mod. Name" line: 

Now enter an appropriate name for the model memory, 
282 Detail program description - Control adjust

99sec

PPM10

8I 

ON

DSC Output

Autorotation

RF transmit

BASIC SETTINGS, MODEL

RF Range Test

The selected switch should be in a location on the 

transmitter which is easily within reach – without 

releasing a joystick – e. g. above the pitch joystick. 

Notice:

More more information about the setting of this 

"emergency shutoff", see the beginning of the second 

following double-page.

Another tip:

Make a habit of giving all switches a common switch-on 

direction; then a quick glance over the transmitter prior 

to the fl ight should suffi ce – all switches off. 

The possible settings of the lines "Automatic C1 

position" and "Motor stop" are not of interest at fi rst.

Additional settings specifi c to helicopters are made in 

the menu ...

"Helicopter type" (page 86)

Under "Swashplate type", select the control of the 

swashplate and/or the pitch function. In this example: 

"3Sv(2rol)".

The lineLinear swashpl." is not of interest at fi rst.

In the line "Rotor direct" you defi ne whether the 

rotor - as viewed from above - rotates to the right or left. 

In other words, whether it rotates counterclockwise or 

clockwise. In this example "right". 

With the default "Pitch min" adopted from the "General 

...

1

bind n/a

BD1 BD2

R12 n/a

Mod.name

Stick mode

RF BIND

BASIC SETTINGS, MODEL

Rcv Ch Map

... which is comprised of the characters available for 

selection on the second screen of the "Mod. Name" line:

 !"#$%&’()+,–./012

3456789:;

Mod Name STARL

FGHIJK L MNOPQRSTUVWX

YZ[¥]^_`abcdefghijk

?@ABCDE

After entering the "Model name" the specifi cations for 

the "Stick mode" and "DSC output" adopted from the 

"General settings" are checked again, for which you 

can change the storage location, if applicable.

An additional option is activated in the line 

"Autorotation". Even if you are not an advanced pilot, 

the autorotation switch should at least be set an an 

emergency shutoff switch for the motor. 

For this purpose, select the line "Autorotation", activate 

the switch assignment by briefl y pressing the central 

SET key of the right touch pad and move one of the twostage switches, e. g. SW 8, to the ON position:

settings", it is checked whether the entry "front" or "back" 

corresponds to your habits and changed, if applicable:

3Sv(2rol)

SEL

Linear. swashpl.

Swashplate

no

Rotor direct right

HELI TYPE

Pitch min. back

"Expo thro lim." in the bottom line of this display is not 

of interest yet.

By now, the servos should be plugged into the receiver 

in the intended sequence:

Receiver power supply

Free or aux. function

Free or aux. function

Tail rotor servo (gyro system)

Roll 1 servo

Pitch-axis 1 servo

Free or speed governor or aux. function

Receiver power supply

Collective pitch or roll 2 or 

Pitch-axis 2 servo

Free or aux. function

Throttle servo or speed controller

Gyro gain

Free or aux. function

Free or aux. function

Notice:

Please note that with the newer Graupner mc and 

mx remote control systems the fi rst pitch servo and 

the throttle servo are reversed when compared with the 

older systems.

The degrees of mixing and mixing directions of the 

swashplate servos for pitch, roll and nick are already 

preadjusted to +61 % in the menu ...
Detail program description - Control adjust 283

"Swashplate mixer" (page 196)

SWASH MIXER

Pitch

Roll

Nick

+61%

+61%

+61%

SEL

... If the swashplate mixer should not follow the joystick 

movements properly, fi rst change the mixing directions 

from "+" to "-" before you change the servo directions in 

the menu ...

"Servo adjustment" (page 90)

S1

S2

S3

Rev cent trv +

0%

0%

0%

100% 100%

100% 100%

100% 100%

0%

0%

100% 100%

100% 100%

S4

S5

... In this menu you can also adjust the travel and the 

directions of the individual servos. As a basic rule you 

should strive to maintain the servo travel 100 % in order 

to attain the best resolution and positioning precision. 

The direction of travel is determined with "Rev." and, 

in the process, make sure that the direction is correct. 

The tail rotor servo must run so that the nose (!) of the 

helicopter follows the tail joystick direction. 

In the menu ...

"Joystick setting" (page 94)

Thr.

Roll

Nick

Tr time +

4

4

4

0.0s

0.0s

0.0s

Tail 4 0.0s

0.0s

0.0s

0.0s

0.0s

TL

GL

GL

GL

St

... adjust the incremental width for each "click" of the 

digital trim keys in the "St" column. 

The C1 trimming only affects the throttle servo for the 

helicopter. At this point there is no need to go into the 

particulars of this trimming ("cut-off trim") once again. 

For this purpose, please refer to page 54. (Thanks to the 

digital trimming, trim values can be automatically saved 

with a model changeover and with the mx-20 HoTT 

and even with a change of the fl ight phase).

An additional setting which is specifi c to helicopters can 

also be made in this menu in which you determine which 

function the trim slider on the pitch joystick should have. 

For this purpose, the setting "TL" is selected or left in 

the "Throttle" line. In doing so, the trim lever corresponds 

to the accustomed idle trim. If you "slide" it all the way 

to the front, the throttle limiter seamlessly adopts the 

throttle release later, which is assigned to "Th.L.12" in 

the ...

""Control adjust" menu (page 100 ... 107)

Input 9

offset

0%

0%

0%

–––

0%

Input

Input

Th.L.12 Ct6

–––

–––

GL

GL

GL

GL

typ

normal

10

11

... whereas "free" is specifi ed for all other inputs.

This input, "Th.L.12" serves as the throttle limiter. It 

only has an effect on output "6", where the throttle servo 

is located. The left proportional rotary control CTRL 6 is 

assigned to the throttle limiter by default.

Once again, as a reminder:

• ith the user of the "throttle limiter" function, you W

do not have to program a fl ight phase "throttle 

preselection". 

• The throttle limiter does not control the throttle servo; 

it only limits the travel of the throttle servo in the full 

throttle direction according to its position. In general, 

the throttle servo is controlled through the throttle 

curve(s) set in the "Helicopter mix", which is why 

Input 6 must be left "free". In the respect, refer also 

to the pages 168 to 170 of the manual. 

• The C1 trimming also affects only the throttle servo 

for the helicopter. At this point there is no need 

to go into the particulars of this trimming ("cut-off 

trim") once again. For this purpose, please refer to 

page 54. (Thanks to the digital trimming, trim can be 

automatically saved values with a model changeover 

as well as with a change of the fl ight phase).

• A detailed description of the idle run base setup 

model and the adjustment of idle and throttle limit 

can be found beginning on page 104.
284 Detail program description - Control adjust

Then switch to the "Travel" column with the arrow keys 

 of the left or right touch pad and increase the now 

inversely highlighted value from +100 % to +125 % with 

a fully opened throttle limiter after briefl y pressing the 

central SET key of the right touch pad:

– travel +

+100%

+100%

+100%

+100%

+100%

+100%

+100%

normal

Input 9

Input10

Input

Th.L.12 +125%

11

In doing so, it is assured that the throttle limiter releases 

the entire throttle travel with the pitch joystick later 

during fl ight.

Adjustment notice for electric helicopters:

Since electric drives do not, by nature, require an idle 

setting, in the scope of the base setup of an electrically 

driven helicopter it must only be ensured that the 

regulating range of the throttle limiter safely exceeds 

and undercuts the normally reached adjustment range 

of the motor control of -100% to +100 %. If necessary, 

therefore, the adjustment of the "travel" setting of 

the throttle limiter described above must be modifi ed 

accordingly, for example, to symmetric 110 %. The 

further adjustment, however, can take place analogously 

to the combustion helicopter described here.

With this process, you have not carried out the basic 

settings for the transmitter as they are needed again 

later for further model programming. 

The actual helicopter-specifi c settings take place 

primarily in the menu ...

""Helicopter mix" (page 164 ... 179)

C1

C1

Pitch

Throttle

Tail

Tail 0%

Roll 0%

Throttle

Roll

Throttle

Tail

Nick

Nick

Throttle

Tail

Swash rotation

Swash limiter

0%

0%

0%

0°

OFF

Normal

Gyro suppress 0%

The "Pitch" function appears right in the fi rst line. By 

pressing the central SET key of the right touch pad, 

you switch to the corresponding submenu. The graphic 

representation of the pitch curve appears here; it is 

initially only defi ned by the points "L" and "H":

Input

Output

Point ?

0%

0%

0%

Pitch

normal

Curve off

Now place point "1" in the center by briefl y pressing the 

central SET key of the right touch pad:

Input

Output

Point 1

0%

0%

Pitch

normal

Curve off

0%

Always try to make due with these three points initially; 

more points can "over-complicate" the matter and are 

more of a burden at this point.

The reference point for the hovering should generally 

be the mechanical center position of the pitch joystick, 

because this position comes closest to the normal 

control feel. Although the curve adjustment enables 

other settings, you must know exactly what you 

are doing. First set the pitch joystick in the center. 

The servos which you had previously set according 

to manufacturer specifi cations have their levers at 

positioned perpendicularly to the servo housing 

(normally). The hovering pitch value of 4 ° to 5 ° is now 

mechanically set at the control levers for the blades. In 

principle, all known helicopters fl y with this setting. 

Then move the pitch joystick towards maximum pitch 

until the limit position. (The vertical line shows you the 

current joystick position.) Now change point "H" of the 

pitch curve with the arrow keys of the right touch pad so 

that the pitch maximum is approximately 9 ° at the rotor 

blades of the main rotor. With a value of approximately 

+50 % this may be the case:
Detail program description - Control adjust 285

H

+100%

+50%

Pitch

normal

+50%

Input

Output

Point

Curve off

Notice:

A rotor adjustment gauge, such as the Graupner 

adjustment gauge, Order No. 61 is very useful in reading 

the angle. 

Now move the pitch joystick toward the pitch minimum 

position until its limit position. Depending on the ability 

of the pilot, adjust the value of point "L" so that the blade 

angle of approach is 0 to -4 °. Now a slightly pitched line 

arises at the hovering points, the so-called pitch curve, 

which can appear as follows: 

L

–100%

–75%

Pitch

normal

–75%

Input

Output

Point

Curve off

Now you can, if you like, move the marking frame 

upward with the arrow keys to the "Curve" line and after 

activation of the value fi eld by briefl y pressing the central 

SET key of the right touch pad, set the curve function of 

the mixer to "on".

L

–100%

–75%

Pitch

normal

–75%

on

Input

Output

Point

Curve

If you now switch to autorotation phase – at the bottom 

left of the display the fl ight phase name "Autorot" 

appears – the "old" pitch curve is again:

?

0%

0%

0%

Pitch

Autorot

Input

Output

Point

Curve off

Now carry out the same setting as before in the normal 

phase. Only at point "H" – at pitch maximum – the pitch 

angle can be increased by approximately 2 °. In doing 

so, you will have somewhat more of an angle to catch 

the model later on (1).

After setting the pitch curve, move the autorotation 

switch back and return to the helicopter mixer menu 

selection by briefl y pressing the central ESC key of the 

left touch pad. From there, switch to the line 

"C1  Thro" in order to adjust the throttle curve.

First the adjustment range of the idle trim must be 

adjusted with the throttle curve. For this purpose, move 

the pitch joystick to its minimum position and then set 

point "L' to approximately -65 %. 

–100%

–65%

C1 Throttle

normal

L –65%

Input

Output

Point

Curve off

With the throttle limiter closed and the idle trim 

completely open, move the pitch joystick back and forth 

somewhat at the minimum limit position. The throttle 

servo may not move with it in the process. No you have 

established a seamless transition from the idle trim to 

the throttle curve. The further settings along the throttle 

curve must be carried out later in fl ight. 

If you switch from this graphic to the autorotation phase 

for testing purposes, the following appears instead of the 

accustomed representation:

OFF

C1 Throttle

Autorot

That means that this mixer is switched off and the 

throttle servo is switched to a fi xed value, which can be 

adjusted as follows: 

Return to the menu list by pressing ESC. As long as you 

are still in the autorotation phase, new submenus are 

listed; specifi cally:
286 Detail program description - Control adjust

Pitch

Thr setting AR

Tailoffset AR

Gyro suppress 0%

Swash rotation 0°

OFF

Autorot

–90%

0%

Swash limiter

The line "Thr. setting AR" is important. Enter the value 

to the right depending on the servo direction to either 

approximately +125 % or -125 %. 

0%

0°

Autorot

0%

SEL

–125%

Pitch

Thr setting AR

Tailoffset AR

Gyro suppress

Swash rotation

Swash limiter OFF

In doing so, the motor is safely switched off in the 

autorotation phase (in case of emergency). Later, when 

you have gained enough experience to practice the 

autorotation fl ight, a more stable idle can be entered 

here.

Adjustment notice for electric helicopters:

Since the motor must also be shut off for electrically 

powered helicopters in case of an emergency, this 

setting is adopted without change. 

The further submenus are not important at the moment. 

By switching off "autorotation", it returns to the fi rst 

menu list.

Select the setting screen of "C1  Tail" in order to 

adjust the static torque balance at the tail rotor. In this 

case, also work with a maximum of three interpolation 

points; everything else is reserved for the experienced 

pilot. For this purpose, change the presetting intended 

for heading lock systems from a uniform 0 % at point 

"L" (pitch minimum) to -30 % and at the opposite end, at 

point "H" to +30 % (pitch maximum). These values may 

have to be corrected in fl ight. If applicable, you must also 

set point "1" in the center when doing so:

0%

0%

0%

C1 Tail

Input

Output

Point

Normal

Curve off

?

Now, for testing purposes, switch back to the 

autorotation phase. Here the setting is also deactivated; 

the tail servo no longer reacts to pitch movements 

(no torque usually arises when the main rotor is not 

powered). All additional interpolation points are not 

currently of importance yet.

If, contrary to the specifi cation, the gyro has a 

transmitter-side sensitivity setting, you still need a free 

proportional control, e.g. CTRL 7. In the menu ...

"Control adjust" (page 100 ... 107)

... you can assign this to the "Gyr" input. Activate the 

control assignment by briefl y pressing the central SET

key of the right touch pad and then turning the rotary 

control until its control number appears in the display: 

Input 5

offset

0%

0%

0%

–––

0%

Throt

Gyro

Input 8 –––

–––

GL

GL

GL

GL

typ

normal

6

7 Ct7

Conclude this entry by briefl y pressing the ESC key of 

the left touch pad and then switch with the arrow key 

of the left or right touch pad to the "- Travel +" column. 

After pressing the central SET key of the right touch 

pad, the maximum sensitivity of the gyro, e. g. 50 %, can 

now be set in the inverse value fi eld. For this purpose, 

rotate the selected control to the corresponding screen 

so that only one value fi eld is represented inversely:

– travel +

+100%

+100%

+100%

+100%

+100%

+100%

+100%

Normal

Input 5

Throt

Gyro

Input 8

6

7 +50%

Now you have a fi xed value as long as the rotary control 

is at the right limit position. The correct value must be 

adjusted in fl ight. 

In the process, however, always observe the 

adjustment instructions accompanying your gyro 

sensor, because your helicopter will not be able to 

fl y otherwise!

To conclude this initial programming, a few words should 

be mentioned about the menu ...
Detail program description - Control adjust 287

"Channel 1 curve" (page 119)

Input

Output

Point ?

0%

0%

0%

C1

normal

Curve

Curve off

This function is a type of "convenient exponential curve" 

for the throttle/pitch joystick and the mixer functions 

connected to it.

If ever, this curve should only be applied "cautiously" at 

the very end, when all adjustments have been made. It 

should never be used for the throttle/pitch adjustment! 

The overlappings result in "nasty" effects.

With this, all helicopter-specifi c settings which can 

be made on the "workbench" are now completed. 

The further fi ne-tuning must take place in fl ight. The 

fl ight-tested, (hopefully) minor (digital) trim settings are 

automatically saved. 

Larger deviations should fi rst be mechanically adjusted 

or adjusted according to the previously discussed 

settings.

Further settings

Following this programming example, you have provided 

a helicopter with a basic adjustment for the hovering 

training and simple trips. Depending on your knowledge 

and experience as a pilot, additional functions can, of 

course, also be activated. 

If you want to fl y at different speeds and with different 

trimming, you activate the so-called "fl ight phases", 

which can be called with assigned switches as an 

alternative to the previously described "normal phase". 

For this purpose, fi rst open the menu ...

"Phase setting" (page 132)

... whereby the symbols appearing in the second 

column after the switch assignment in the "Phase 

assignment" menu have the following meanings:

"–": No phase switch available

"+": Phase switch available

"": Currently active phase

Pha1

Pha2

Pha3

Name ph.Tim.

Pha4

Autorot

–

–

–

Auto +



However, you should consider beforehand whether you 

want to activate the up to six additional fl ight phases 

with single switches or, more logically, with three-stage 

switches in addition to the autorotation phase. The latter 

possibility is more logical and usually more clearly laid 

out.

In the upper fi gure the line "Autorot" is already selected. 

When activated, the autorotation phase always has 

precedence over any other phases you assign switches to. 

However, in the "Name" column you fi rst assign 

"meaningful" names to Phases 1 to 3, which are 

adopted from a list. These identifi cations serve for the 

better differentiation and are shown later in the base 

screen and for all fl ight-phase dependent menus, for 

example:

Pha1

Pha2

Pha3

Name ph.Tim.

Pha4



+

+

Normal

Hover

–

–

0.1s

0.1s

0.1s

0.1s

0.1s

Speed

Auto Autorot

Then, in the fourth column, enter the switching time 

with which the FROM phase should switch TO the next 

respective phase. Approximately 1 s should suffi ce:

Pha1

Pha2

Pha3

Name Sw.time

Pha4



+

+

Normal

Hover

–

–

1.1s

1.1s

5.0s

0.1s

Speed

Auto Autorot

1.1s

This value can also be adjusted later according to your 

personal preferences. Please observe in the process 

that TO the autorotation phase, whose name is defi ned 

as "Autorot", is switched without a time delay. If 

necessary, enter the time with which a change FROM 

the autorotation phase to a different phase should be 

affected.

In order to be able to switch between the individual fl ight 

phases, the assignment of the individual switches or the 

three-stage switch is necessary.
288 Detail program description - Control adjust

The assignment of the switch takes place in the menu ...

"Phase assignment" (page 134)

Under "C" and "D" assign the three-stage switches SW 

4 + 5, for example:

PHASE ASSIGNMENT

A B C D E F 

1 Normal

2 4 5

prior combi

Now you must assign the corresponding fl ight phase 

from the "Phase setting" menu to the respective switch 

position. Since you have already assigned names, the 

name of the phase "1 Normal" appears to the right in the 

display. If the already assigned autorotation switch was 

activated, the following warning message appears in the 

display:

PHASE ASSIGNMENT

A B C D E F 

1 Normal

2 4 5

prior combi

Autorot

As a reminder:

The autorotation phase has absolute precedence.

Therefore, move the autorotation switch back and then 

move the selected switch, in our example the threestage switch SW 4 + 5, to the one limit position. Then 

switch to the bottom right with the arrow keys and 

activate this input fi eld:

A B C D E F 

2 4 5

1 Normal

PHASE ASSIGNMENT

prior combi

Now select the desired fl ight phase for this switch 

position - for example, "2 Hover" ...

A B C D E F 

2 4 5

2 Hover

PHASE ASSIGNMENT

prior combi

... and confi rm this selection by briefl y pressing the 

central SET key of the right touch pad or move the 

switch to the other limit position and defi ne the name for 

this switch position, such as "3 Speed". 

A B C D E F 

2 4 5

3 Speed

PHASE ASSIGNMENT

prior combi

The switch center then receives the name "1 Normal" as 

shown above to the left. 

Notice:

Exchanged or different name assignments for the 

three switch positions are, of course, also possible. 

For example, with the use of one of the rotational speed 

controllers programmed according to the description 

in the next column, a sequences like "normal / hover / 

acro" would be logical.

The model settings made before the assignment of a 

phase switch are now in the fl ight phase "Normal". This 

is the phase which is called after the above defi nition in 

the switch center position.

This normal setting, which was already tested in fl ight, 

can be copied to a different fl ight phase so that fl ying 

can take place in the same manner in every phase at 

fi rst. For this purpose, use the menu ...

"Copy / Erase" (page 64) 

=>

=>

=>

=>

Copy flight phase =>

Erase model

Copy model–>model

Export to SD

Import from SD

With the operation of the fl ight phases, it is possible 

to carry out changes in the phase-dependent menu 

for each individual phase. Since the mx-20 HoTT 

has digital trimming, in addition to the fl ight-phase 

dependent menu settings in the helicopter program, 

the trim positions of roll, nick and tail rotor joystick are 

also saved depending on the fl ight phase, see menu 

"Joystick setting" page 94: 

Thr.

Roll

Nick

Tr time +

4

4

4

0.0s

0.0s

0.0s

Tail 4 0.0s

0.0s

0.0s

0.0s

0.0s

TL

GL

GL

GL

St
Detail program description - Control adjust 289

Enhancement recommendation: 

Rotational speed regulator

At some point in time you may want to install a 

rotational speed regulator in the helicopter, such as 

mc-Heli-Control, in order to be able to fl y with speeds 

automatically kept at a constant. In the process, it is 

logical to couple the individual rotational speeds with the 

fl ight phases so that further additional adjustments are 

possible.

It is mandatory for the transmitter-side programming 

that the rotational speed regulator was installed 

and programmed according to the manufacturer's 

instructions. Of course, the mx-20 HoTT also enables 

further possibilities for the realization of different speeds 

in the individual phases. For a practical recommendation 

with maintenance of the throttle limiter function, see the 

description beginning on page 169.

If you have adjusted your helicopter according to 

this programming principle, it is not yet a competition 

helicopter, but it already permits sophisticated fl ying. 

You should only activate additional functions if the model 

fl ies faultlessly so that the (desired) improvements 

are also easy to follow. Insofar as possible, activate 

individual functions on an individual basis so that you 

can actually recognize and attribute the change. Bear 

in mind that it is not the quantity of functions used that 

distinguishes good pilots, but what they can do in terms 

of fl ying with relatively little. 
290 Appendix

Vario moduleGraupner HoTT

Order No. 33601

Vario with altitude signals and 5 ascend and descend signal tones 

each, altitude display and memory of the min. and max. altitude

• Additional warning thresholds for min. altitude, max. altitude, rate of 

ascend and descend in two stages

• Adjustable warning time: OFF, 5, 10, 15, 20, 25, 30 seconds, always

• Adjustable warning repetition time: Always, 1, 2, 3, 4, 5 min, once

• The Vario sensor can be connected directly at the telemetry input of 

the receiver.

Technical data

• Altitude measurement: -500 m ... +3000 m

• Resolution: 0.1 m

• Vario sensitivity: 0.5 m/3s, 1 m/3 s, 0.5 m/s, 1 m/1 s, 3 m/s 

programmable by tone

• Average calculation: 4 - 20 measurements programmable per 

measurement value

PRX (Power for Receiver)

Order No. 4136

Highly developed, stabilized receiver current supply with intelligent 

power management. 

The unit ensures a stabilized and adjustable current supply of the 

receiver in order to increase the reliability of the current supply even 

further. Suitable for various receiver batteries in order to guarantee 

an uncomplicated and wide range of application. Even if the battery 

voltage is only interrupted for a short time, this is recorded and 

displayed in order to counteract an under-dimensioning or even the 

failure of the receiver battery with this notice.

• For the operation of one or two receiver batteries. 

(Simultaneous discharge with the operation of two batteries)

• Suitable for fi ve or six-cell NiMH or two -cell LiPo or LiFe batteries. 

Graupner/JR, G3.5, G2 and BEC plug systems.

• Three adjustable levels for the output voltage for the supply of the 

receiver (5.1V / 5.5V / 5.9V).

• Two ultra-bright LEDs show the operating statuses of Battery 1 and 

Battery 2 separately.

• Integrated high-quality On/Off switch

• High-current resistant design

• Flatter design of the switch and the LEDS in order to not infl uence 

the appearance and characteristics of the model.

• Linear layout of fastening lugs, LEDs and switches for a simple 

installation using an accompanying hole template.

GPS/Vario module Graupner HoTT

Order No. 33600

Vario with altitude signals and and fi ve ascend and descend signal 

tones as well as integrated GPS with range fi nding, distance 

measurement, display of the fl ight direction and the coordinates

• Additional warning thresholds for min. altitude, max. altitude, rate of 

ascend and descend in two stages

• Altitude display and memory of the min. and max. altitude.

• Adjustable warning time: OFF, 5, 10, 15, 20, 25, 30 seconds, always

• Adjustable warning repetition time: Always, 1, 2, 3, 4, 5 min, once

• The GPS/Vario sensor can be connected directly at the telemetry 

input of the receiver.

Vario technical data:

• Altitude measurement: -500 m ... +3000 m

• Resolution: 0.1 m

• Vario sensitivity: 0.5 m/3s, 1 m/3 s, 0.5 m/s, 1 m/1 s, 3 m/s 

programmable by tone

• Average calculation: 4 - 20 measurements programmable per 

measurement value

 Appendix
Appendix 291

General Engine-Module Graupner HoTT

Order No. 33610

General sensor for Graupner HoTT receivers and models with 

combustion or electric motor:

• 2x temperature and voltage measurements with warning thresholds 

for min. and max. voltage and min. and max. temperature

• Single cell measurement with warning thresholds for min. voltage

• Voltage, current and capacity measurement with warning thresholds 

for min. and max. voltage, max. capacity and max. current

• Programmable current limiting

• Current limiting with shunt resistors 2 x 1 mOhm parallel = 0.5 mOhm

• Rotational speed measurement and warning thresholds for min. and 

max. rotational speed

• Fuel measurement with warning thresholds in 25 % increments 

(after software update).

• Adjustable warning time: OFF, 5, 10, 15, 20, 25, 30 seconds, always

• Adjustable warning repetition time: Always, 1, 2, 3, 4, 5 min, once

• 2x temperature selectively 0 to 120 °C or 200 °C and voltage 

measurement up to 80 V DC

• 1x rotational speed measurement up to 100,000 rpm with a twoblade propeller

• 1x speed controller/servo input, 1x rotational speed regulatio

n input, 1x speed controller/servo output for rotational speed 

regulation

• 1x current, voltage and capacity measurement up to 40 A (pulse 1 s 

up to 60 A) and up to 30 V

• 1x single cell monitoring for 2 - 6S lithium batteries (LiPo, LiIo, LiFe) 

• etc.; see www.graupner.de for the respective product

General Air-Module Graupner HoTT

Order No. 33611

General sensor for Graupner HoTT receivers and models with 

combustion or electric motor:

• Vario with altitude signals and ascend and descend signals and 

additional warning thresholds for min. altitude, max. altitude, rate of 

ascend and descend in two stages

• Altitude display (-500 ... +3000 m) and memory of the min. and max. 

altitude.

• 2x temperature and voltage measurements with warning thresholds 

for min. and max. voltage and min. and max. temperature

• Single cell measurement with warning thresholds for min. voltage

• Voltage, current and capacity measurement with warning thresholds 

for min. and max. voltage, max. capacity and max. current

• Rotational speed measurement with rotational speed regulation 

(programmable) and warning thresholds for min. and max. rotational 

speed

• Fuel measurement with warning thresholds in 25 % increments.

• Adjustable warning time: OFF, 5, 10, 15, 20, 25, 30 seconds, always

• Adjustable warning repetition time: Always, 1, 2, 3, 4, 5 min, once

• 2x temperature selectively 0 to 120 °C or 200 °C and voltage 

measurement up to 80 V DC

• 1x rotational speed measurement up to 100,000 rpm with a twoblade propeller

• 1x speed controller/servo input, 1x rotational speed regulation input, 

1x speed controller/servo output for rotational speed regulation

• 1x current and voltage and capacity measurement up to 40 A (pulse 

1s: 60 A ) and up to 30 V

• etc.; see www.graupner.de for the respective product

Electric Air-Module Graupner HoTT

Order No. 33620

General sensor for Graupner HoTT receiver and models with electric 

motor

• Vario with altitude signals, ascend and descend signals as well as 

additional warning thresholds for min. altitude, max. altitude, rate of 

ascend and descend in two stages

• Altitude display (-500 ... +3000 m) and memory of the min. and max. 

altitude.

• 2x temperature and voltage measurements with warning thresholds 

for min. and max. voltage and min. and max. temperature

• Single cell measurement 2 ... 14S with warning thresholds for min. 

voltage

• Voltage, current and capacity measurement with warning thresholds 

for min. and max. voltage, max. capacity and max. current

• Adjustable warning time: OFF, 5, 10, 15, 20, 25, 30 seconds, always

• Adjustable warning repetition time: Always, 1, 2, 3, 4, 5 min, once

• 2x temperature selectively 0 to 120 °C or 200 °C and voltage 

measurement up to 80 V DC

• 1x speed controller input, 1x speed controller output for single cell 

undervoltage correction

• 1x current and voltage and capacity measurement up to 150 A 

(short-term 1 sec 320 A) and up to 60 V

• 1x single cell monitoring for 2 - 14S lithium batteries (LiPo, LiIo, LiFe)

• 1x telemetry connection for receiver
292 Appendix

Graupner HoTT Smart-Box

Order No. 33700

Wide-ranging functions combined into one device make the SMART 

BOX your future smart companion. Whether it comes to displaying 

real-time telemetry data or settings are made on your HoTT system, 

8 x 21 characters on a large display enable easy use. An integrated 

sounder for the emission of an acoustic signal and warning tone 

enhances the fl exible use of the BOX even further.

Using the accompanying installation set, the device can be mounted 

on brackets of the transmitter and is thus optimally positioned to 

enable the reading of real-time telemetry data even while controlling 

your model.

The capability of user-installed updates ensures that the SMART BOX 

always has the latest software and can be safely expanded with future 

functions. 

• Transmitter voltage display with 

adjustable warning threshold

• Region setting

• Signal quality Range test • 

• Receiver voltage Receiver temperature • 

• Servo neutral position Servo reversal • 

• Cycle time Servo travel • 

• Fail-Safe settings Channel switching • 

• Servo test Mixer settings • 

Dimensions: approx. 76 mm x 72 mm x 17 mm (L x W x H)

Weight: approx. 55 g

RPM Magnet Sensor Graupner HoTT

Order No. 33616

RPM Optical Sensor Graupner HoTT

Order No. 33615

Graupner HoTT USB interface

Order No. 7168.6

This USB interface is required together with the separately available 

adapter cable, Order No. 7168.6A, for the updating of receivers and 

sensors and the mx-20 HoTT transmitter can be updated directly 

with the USB cable included in the scope of delivery of the interface. 

Graupner HoTT adapter cable

Order No. 7168.6A

This adapter cable is required together with the separately available 

USB interface, Order No. 7168.6, for the updating of receivers and 

sensors. The mx-20 HoTT transmitter can be updated directly with 

the USB cable included in the scope of delivery of the interface.
FCC Information 293

Graupner mx-20 HoTT #33124

FCC ID: ZKZ-MX-16-20A

FCC Statement

1. This device complies with Part 15C of the FCC 

Rules. Operation is subject to the following two 

conditions:

 (1) This device may not cause harmful interference.

 (2) This device must accept any interference 

received, including interference that may cause 

un desired operation.

2. Changes or modifi cations not expressly approved by 

the party responsible for compliance could void the 

user‘s authority to operate the equipment.

NOTE

This equipment has been tested and found to comply 

with the limits for a Class B digital device, pursuant to 

Part 15 of the FCC Rules. These limits are designed 

to provide reasonable protection against harmful 

interference in a residential installation. This equipment 

generates uses and can radiate radio frequency energy 

and, if not installed and used in accordance with the 

instructions, may cause harmful interference to radio 

communications. However, there is no guarantee that 

interference will not occur in a particular installation. 

If this equipment does cause harmful interference to 

radio or television reception, which can be determined 

by turning the equipment off and on, the user is 

encouraged to try to correct the interference by one or 

more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and 

receiver.

FCC Information

• Connect the equipment into an outlet on a circuit 

different from that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV 

technician for help. 

FCC Radiation Exposure Statement

This equipment complies with FCC radiation exposure 

limits set forth for un uncontrolled envirionment. This 

equipment should be installed and operated with a 

minimum distance of 20 cm between the antenna and 

your body.
294 Declaration of Conformity

 Declaration of Conformity Konformitätserklärung gemäß dem Gesetz über Funkanlagen und Telekomunikationsendeinrichtungen (FTEG) und der Richtlinie 1999/5/EG (R&TTE) Declaration of Conformity in accordiance with the Radio and Telecomunikations Terminal Equipment Act (FTEG) and Directive 1999/5/EG (R&TTE) Graupner GmbH & Co. KG Henriettenstraße 94-96 D-73230 Kirchheim/Teck erklärt, dass das Produkt: declares that the product

Geräteklasse: 2Equipment classden grundlegenden Anforderungen des § 3 und den übrigen einschlägigen Bestimmungen des FTEG (Artikel 3 der R&TTE) entspricht. complies with the essential requirements of § 3 and the other relevant provisions of the FTEG (Article 3 of theR&TTE Directive).Angewendete harmonisierte Normen:Harmonised standards applied

EN 60950:2006EN 301 489-1 V1.7.1EN 301 489-3 V1.4.1EN 300 328 V1.7.1 

 Health and safety requirements pursuant to § 3 (1) 1. (Article 3 (1) a)) Protection requirement concernig electromagnetic compatibility § 3 (1) 2, Artikel 3 (1) b)) Measures for the efficient use of the radio frequency spectrum § 3 (2) (Article 3 (2))

Kirchheim,09. März 2011 Stefan Graupner, Geschäftsführer 

Stefan Graupner, Managing Director

Graupner GmbH & Co. KG Henriettenstraße 94-96 D-73230 Kirchheim/Teck GermanyTel: 07021/722-0 EMail: info@graupner.de Fax: 07021/722-188

Gesundheit und Sicherheit gemäß § 3 (1) 1. (Artikel 3 (1)a)) 

Schutzanforderungen in Bezug auf elektromagnetische 

Verträglichkeit § 3 (1) 2, Artikel 3 (1) b))

Maßnahmen zur effizienten Nutzung des Frequenzspektrums 

§ 3 (2) (Artikel 3 (2))

mx-12 HoTT - No. 33112, mx-16 HoTT - No. 33116,mx-20 HoTT - No. 33124,GR-12 HoTT - No. 33506, GR-16 HoTT - No. 33508,GR-24 HoTT - No. 33512
Warranty 295

Wir gewähren auf dieses Erzeugnis eine Garantie von 

This product is warrantied for

Sur ce produit nous accordons une garantie de 24 Monaten

months Warranty Certifi cate mois

Servicestellen / Service / Service après-vente

Graupner -Zentralservice

Graupner GmbH & Co. KG

Henriettenstrasse 94 - 96

D-73230 Kirchheim

Service hotline

 (+49) 0 18 05 47 28 76*

Monday ... Friday

9:30 ... 11:30 & 13:00 ...15:00

United Kingdom

Graupner Service

Brunel Drive

GB, NEWARK, 

Nottingham shire

NG242EG

 (+44) 16 36 61 05 39

Sverige

Baltechno Electronics

Box 5307

S 40227 Göteborg

 (+46) 31 70 73 00 0

Schweiz

Graupner Service

Wehntalerstrasse 37

CH 8181 Höri

 (+41) 43 26 66 58 3

Luxembourg

Kit Flammang

129, route d’Arlon

L 8009 Strassen

 (+35) 23 12 23 2

France

Graupner France

Gérard Altmayer

86, rue St. Antoine

F 57601 Forbach-Oeting

 (+33) 3 87 85 62 12

Espana

Anguera Hobbies

C/Terrassa 14 

E 43206 Reus (Tarragona).

 (+34) 97 77 55 32 0 

info@anguera-hobbies.com

Ceská Republika

Slovenská Republika

RC Service Z. Hnizdil

Letecka 666/22

CZ 16100 Praha 6 - Ruzyne

 (+42) 2 33 31 30 95

Belgie/Belgique/Nederland

Jan van Mouwerik

Slot de Houvelaan 30

NL 3155 Maasland VT

 (+31) 10 59 13 59 4

Italia

GiMax

Via Manzoni, no. 8

I 25064 Gussago

 (+39) 030 25 22 73 2

* 0.14 cent / minute from a 

German Telecom land-line. 

Calling price variations 

possible for calls from cell 

phones or from the land-lines 

of other providers.

Graupner GmbH & Co. KG, Henriettenstrasse 94 - 96, 

D-73230 Kirchheim/Teck provides a warranty for this product 

of 24 months from the date of purchase. The warranty is 

only valid for the material or functional defects already 

present at the time of the purchase of the product. Schäden, 

die auf Abnützung, Überlastung, falsches Zubehör oder 

unsachgemäße Behandlung zurückzuführen sind, sind von 

der Garantie ausgeschlossen. Die gesetzlichen Rechte und 

Gewährleistunsansprüche des Verbrauchers werden durch 

diese Garantie nicht berührt. Bitte überprüfen Sie vor einer 

Reklamation oder Rücksendung das Produkt genau auf 

Mängel, da wir Ihnen bei Mängelfreiheit die entstandenen 

Unkosten in Rechnung stellen müssen.

Graupner GmbH & Co. KG, Henriettenstraße 94 - 96. D-73230 

Kirchheim/Teck, Germany guarantees this product for a period of 

24 months from date of purchase. The guarantee applies only to 

such material or operational defects which are present at the time 

of purchase of the product. Damage due to wear, overloading, 

incompetent handling or the use of incorrect accessories is not 

covered by the guarantee. The user ́s legal rights and claims 

under guarantee are not affected by this guarantee. Please check 

the product carefully for defects before you are make a claim or 

send the item to us, since we are obliged to make a charge for 

our cost if the product is found to be free of faults.

La société Graupner GmbH & Co. KG, Henriettenstraße 94-96, 

D-73230 Kirchheim/Teck, accorde sur ce produit une garantie 

de 24 mois à compter de la date d’achat. La garantie ne 

s’applique qu’aux défauts de matériel et de fonctionnement 

du produit acheté. Les dommages dus à une usure, à une 

surcharge, à l’emploi d’accessoires non compatibles ou à 

une manipulation non conforme sont exclus de la garantie. 

Cette garantie ne remet pas en cause les droits légaux 

des consommateurs. Avant toute réclamation ou retour de 

matériel, vérifi ez précisément les défauts ou vices constatés, 

car si le matériel est conforme et qu’aucun défaut n’a été 

constaté par nos services, nous nous verrions contraints de 

facturer le coût de cette intervention.

Garantie-Urkunde

Warranty certifi cate / Certifi cat de garantie

mx-20 HoTT Set

 Order No. 33124

Übergabedatum:

Date of purchase/delivery:

Date d’achat :

Name des Käufers:

Owner ́s name:

Nom de I`acheteur :

Straße, Wohnort:

Complete address:

Adresse complète :

Firmenstempel und Unterschrift des Einzelhändlers:

Stamp and signature of dealer:

Cachet et signature du détaillant :
HOPPING.TELEMETRY.TRANSMISSION

GRAUPNER GMBH & CO. KG

POSTFACH 1242

D-73220 KIRCHHEIM/TECK

GERMANY

http://www.graupner.de

Changes and delivery options reserved. Available only 

through dealerships. A directory of suppliers will be 

provided. No liability is accepted for print errors.

Printed in Germany PN.PK-01

Although the information provided in these instructions has been carefully scrutinized 

for viability, no form of liability can be accepted for errors, omissions or print errors. 

Graupner reserves the right to change the described hardware and software features at 

any time without prior notifi cation.