From: sham@cs.arizona.edu
Newsgroups: rec.models.rc,news.answers
Subject: R/C Flying: Part 1 of 2/rec.models.rc FAQ
Summary: A Beginner's Guide to Radio Controlled Flying
Date: 14 Sep 92 15:00:09 GMT
Expires: 26 Oct 92 15:00:08 GMT
Reply-To: shamim@cs.arizona.edu
Followup-To: rec.models.rc
Organization: Dept. of Computer Science, University of Arizona
Supersedes: <20659@optima.cs.arizona.edu>

Archive-name: RC-flying-FAQ/part1
Last-modified: Aug. 24 1992

Greetings! This is the "Radio Control (R/C) Flying" help file, containing
information of general interest to beginners. This file is posted regularly
(every 28 days). I have tried to address all questions a beginner may have; if
your question isn't here, please send it to me so I can include for the next
person needing help.

Remember, no amount of FAQ reading can substitute for an instructor!

Shamim Mohamed
shamim@cs.arizona.edu
{uunet,cmcl2,noao..}!arizona!shamim

============================== Cut Here ======================================

Authors:
   W.A. - Wayne Angevine (angevine@badger.Colorado.EDU)
   G.H. - Gary Hethcoat (gdh@dobbs.Eng.Sun.COM)
   K.S. - Ken Summers (cs3871aa@triton.Unm.EDU)
   S.M. - Shamim Mohamed (shamim@cs.Arizona.EDU)

Thanks to the following for comments and reviews:
   Dave Burritt (drb@druwy.Att.COM)
   Jeff Capehart (jdc@reef.Cis.Ufl.EDU)
   Warren R Carithers (wrc@cs.Rit.EDU)
   Carl Kalbfleisch (cwk@boomer.Ssc.GOV)


Contents:

-Part 1
   General           -- Organizations, radios                  (S.M.)
   Building          -- Kits, ARFs and Scratchbuilding         (S.M.)
   The rec.models.rc ftp site
                     -- to get plotfoil, airfoil data, circuit diagrams etc.
   Learning to Fly   -- Instructors, Pre-flight checks    (S.M.,G.H.)
   Gliders           -- Launching, Staying Up, Recommendations and Costs
                                                               (S.M.)
-Part 2
   Power (gas)                                            (G.H.,K.S.)
   Electrics         -- Advantages, Equipment, Motor Specs., Recommendations
                                                               (W.A.)
   Some Aerodynamics -- Speed, Turning, Stalls                 (S.M.)

-----------------------------  General  --------------------------------------

>Should I start with powered flight, or with a glider?

Depends on preferences. I prefer gliders; that's where I started. The
2m (6 foot wingspan) class is a good size - large enough to be easy to
fly but small enough for easy transport.  Gliders are easier to fly and
more acceptable to the non-flying community - no noise or mess. Gliders
are also cheaper (at least the trainers are) than powered planes - no
fuel, batteries, starter etc. to worry about. Electric Flight is silent
and clean so finds greater acceptance from neighbours etc. at the
flying field, although some people feel that electrics are not
robust/easy enough for beginners. There is a little more paraphernalia
- you may need spare battery packs, but you can fly from smaller
fields.  Power will let you fly longer, and your model doesn't need to
be as light as with electric (so it's likely to be easier to build);
however, you may have to go to a field far from populated areas. The
type known as "40 size" are the most popular, about 50" wing span and a
.40 cu. in. engine.

>Are there any organisations etc. I can join for information?

Ask at your local hobby shop - there may be a club in your neighbourhood.
This is the best way to meet other pilots and find an instructor. Most
pilots will more than glad to help you out.  If you can find a club, for
an instructor, choose someone who is smooth in flying his/her plane and
that you get along with. Remember, the ones best at flying (hangar or
otherwise) may not always be the best instructors.

An organisation well worth joining is the Academy of Model Aeronautics
(AMA).  They are the modellers' main voice where it matters - they
liaison with the FCC, the FAA and Congress. It is an affiliate of the
National Aeronautic Association (NAA) and is the US aeromodeling
representative of the Federation Aeronautique Internationale (FAI).
Membership in the AMA also gets you $1,000,000 of liability insurance,
without which most fields will not allow you to fly. You also need to be
an AMA member to participate in contests. Besides, you also get a
magazine, `Model Aviation' which is rather good in itself, and it keeps
you informed about the state of the hobby. So JOIN AMA!!! You can write
to: Academy of Model Aeronautics, 1810 Samuel Morse Drive, Reston, VA
22090.  Membership is $40 per year (and well worth it). Their phone number
is (703) 435 0750.

--- Radios:

>Since a trainer needs only 2 or 3 channels, should I get one of the cheap
> radio systems?

   Don't bother with the cheap 2 or 3 channel sets - get a 4-ch system.
It will come with NiCad rechargeable batteries and (usually) 3 servos;
this is the most popular and most cost-effective kind of system. You can
put the main pitch control (elevator) and the main turning control (in
this case the rudder) on one stick, which is how most people (and thus
most instructors) fly.  The cheaper systems come with the controls on
separate sticks and you will have tough time finding someone willing to
teach you with that setup.

>What is a "1991" system?

Strongly recommended!  A "1991" system is so named because in 1991 the
radio control frequency regulations changed, which effectively made the
"old-style" radios unusable.  The "old-style" radios have a separation
between channels of 40 kHz.  In 1991, a separation of 10 kHz will be
needed, this even though R/C channels will still be 20 kHz apart - because
the FCC in their infinite wisdom have created channels for pagers and such
_between_ the R/C channels, i.e. 10 kHz away from our frequencies. The
Airtronics VG4 FM series is an inexpensive example, and is about $120 mail
order.

If you can afford it, a system that has a "buddy box" is a really good
idea. This is an arrangement where the instructor's radio is hooked up to
yours, and he just has to release a button on his radio to take over
control, rather than wrestling the radio from your grip. If you do this,
be aware that you need to get the same (or compatible) radio as your
instructor.

----------------------------  Building  ---------------------------------------

>Should I start with plans and build my own plane from scratch, buy a kit
>plane with wood and plans included, or go with one of those everything
>included ready to fly planes.

There are a few good trainers that are ready to fly (or almost ready to
fly, aka ARF). ARF planes are usually heavy and hard to repair. The new
generation of ARF kits is all wood and better built but more expensive.
The better kits have parts that are machine cut, the somewhat cheaper
ones are die-cut. You'll probably have to so a little more work with a
die-cut kit, mostly in separating parts and sanding them.

ARFs vs. kits: this is a matter of opinion, but more people seem to think
that kits are a better idea for beginners. Pro kits: you get valuable
building experience and are able to do repairs. Moreover trainers are
good planes to learn to build as well as to fly, and most of them are
cheaper than most ARFs. Pro ARFs: you can be flying sooner, and you have
less emotional investment in the plane so when you crash you don't feel
as bad.
However: regardless of what you chose, your chances of a painless
education are greatly improved if you have an instructor - both for
building and for flying.

Remember, the plane you buy doesn't have to be good looking, it just has
to teach you to fly! Many pilots after building a beautiful model are so
afraid to crash that they never fly. Far better to have a scummy looking
plane that you don't mind crashing again and again and learning to fly
than to have a slick model that you can only mount on a stand! After you
are proficient you'll have plenty of time to build good-looking planes.

It seems to be the general consensus that there are enough decent kits
around that building from scratch is not really worth the effort unless
you are into design or obscure scale models. If this is what you want,
you may find the "plotfoil" program (available from the rec.models.rc ftp
site and from comp.sources.misc archives) useful.

Covering: for now, stay with Monokote. It's reasonably easy to apply, not
too heavy, and fuelproof. (The label gives directions.)

------------------------ The rec.models.rc ftp site --------------------------

Nur Iskander Taib <ntaib@silver.ucs.indiana.edu> has been kind enough to
establish an ftp site for the use of the rec.models.rc community. Use
anonymous ftp to log in to "bigwig.geology.indiana.edu" and go to the
directory called "models" . You will find subdirectories called
"airfoil", "faq" and "circuits".  These contain, respectively:
   plotfoil - a program to plot airfoil sections on PostScript printers.
              It can also draw spars and sheeting allowances, and can
              plot airfoils of arbitrary chords (on multiple sheets). It
              also includes a library of airfoil data, including many
              from Soartech 8.  
   faq      - contains this FAQ file.
   circuits - circuit diagrams for modelling applications, including
              "smart" glow-plug drivers.

Other FTP sources:
   Sometimes people have trouble getting to bigwig. Plotfoil is also available
from comp.sources.misc, which is archived at many sites, including sites in
France and Australia. Get Volume 31, parts 28-30 (archive name: plotfoil).
Contact your sysadmin, or read the periodic posting in comp.sources.misc for
more information on how to reach the nearest one.
   This FAQ is available from pit-manager.mit.edu, the news.answers archive. It
is in /pub/usenet/news.answers/RC-flying-FAQ/part*.
   These two sources are guaranteed to be up-to-date, since it is all done
automagically.

------------------------ Learning to Fly --------------------------------------

The most important point, one which cannot be overstressed:
   GET AN INSTRUCTOR!
Here's what one beginner had to say:

> I just started doing RC planes myself. In fact, yesterday I flew my
> plane for the first time (with an instructor). He took off for me,
> got the plane at a real high altitude and then gave me the controls.
> I did OK (in my opinion) but did have to give him the controls twice
> in order to get the plane into stable flight again. I figured the
> controls would be sensitive but I did not realize HOW SENSITIVE. I
> only had to move them about 1/8 of an inch to turn.
>
> There is no way I could have landed the thing without crashing.
>
> By the way I am a full scale pilot. That did not help me at all.
> In fact I think it hurt. I didn't realize how much I use the "feel
> of the plane" when flying a real one. Obviously you have no feel
> whatsoever with RC planes.

You probably won't have any really bad (i.e.  irreparable) crashes. (Of
course, you'll still crash.) Also make _sure_ you have your instructor
check your plane thoroughly _before_ the first flight - as someone said,
"it is much better to go home with no flights and one airplane than go
home with one half a flight and many little pieces." This is really,
REALLY important.

--- Pre-flight Checklist ---

When your model is ready to fly, make sure it is thouroghly checked over by
someone who has done alot of building and flying. When I say thouroughly,
I don't mean just picking it up and checking the balance and thumping the
tires a few times. Every detail of setup and connection should be gone over
in detail. If your instructor doesn't want to spend this much time
checking your plane, find a new instructor.

The importance of this pre-flight check cannot be overemphasized! Many planes
are lost due to a simple oversight that could have been caught by a pre-flight!

Here's a checklist:

Before the first flight:
-----------------------

1) Weight
        - is the model too heavy?

2) Balance
        - Is the center of gravity (fore and aft) within the range shown
          on the plans?
        - Is the model balanced side to side? (right and left wings of
          equal weight)

3) Alignment
        - Are all flying surfaces at the proper angle relative to each other?
        - Are there any twists in the wings? (other than designed-in washin
          or washout)

4) Control surfaces
        - Are they all *securely* attached? (i.e. hinges glued, not just
          pushed in)
        - Are the control throws in the proper direction *and* amount?
          (usually indicated in the plans)

5) Control linkage
        - Have all linkages been checked to make sure they are secure?
        - Are all snap-links closed?
        - Have snap-links been used on the servo end? (They are
          more likely to come loose when used on the servo)
        - Have all screws been attached to servo horns?

6) Engine and fuel (if applicable)
        - Has the engine been thoroughly tested?
        - Are all engine screws tight?
        - Has the engine been run up at full throttle with
          the plane's nose straight up in the air? (To make sure it
          won't stall when full power is applied on climbout)
        - Is the fuel tank level with the flying attitude of the plane?
        - Is the carburetor at the same height (not above) as the fuel tank?
        - Is the fuel tank klunk in the proper position and moving freely?

7) Radio
        - Has a full range check been performed?
        - Has the flight pack charge been checked with a voltmeter?
        - Have the receiver and battery been protected from vibration
          and shock?
        - Is the receiver's antenna fully extended and not placed within a
          fuselage with any sort of metallic covering?

After repair:
------------

The checklist should be gone through again, with particular attention to
the areas that were worked on or repaired.

Before EVERY flight:
-------------------

1) Start the engine (if applicable) and test the entire throttle range. Run
   it at full throttle with its nose in the air for 15 seconds or so.

2) Check the receiver flight pack with a voltmeter to ensure enough charge.

3) Check the control throw direction for all surfaces. It's very easy to
   do a repair or radio adjustment and forget to switch these.

If you can't find an expert that is willing to teach you, it is best to
start with a 2-3 channel model with a long wingspan and alot of dihedral.
The ideal thing to start with here would be a 2 channel glider. If you
MUST start with a powered plane, a 6' foot powered glider, like the Piece
O' Cake from Dynaflite is a good way to go.

------------------------ Gliders  ---------------------------------------------

A 2-channel (rudder+elevator) polyhedral [see below] glider is just about
the easiest way to learn to fly, and is highly recommended. Once you can
handle that you can move up to rudder-elev.-spoiler-flap competition
ships or (on the slope) rudder-elevator-aileron-spoiler aerobatic ships.

Sailplane plug (aka religious sermon): ... don't think glider flying is
just "launch, glide back" - It's very easy to get 30+ minute flights and
about 1000' altitude.  Remember, power flying is limited by the size of
the fuel tank (about 10 minutes) and gliders are limited by the receiver
batteries (about 2 hrs).  And glider flying is *much* more challenging (my
opinion, of course), while at the same time being easier to learn. And no
fuel costs, no starting hassles, no cleanup afterwards...  Also, many
cities have ordinances prohibiting model engines, which means the flying
fields are outside city limits.  BUT, since sailplanes don't have those
nasty, messy smelly things, we can fly in any large enough area!

>Are most gliders hand launched, or do they have a small engine to get
them up?

Gliders are usually launched by a "hi-start" - a section of rubber with
about 500' of line. It is hooked to the plane and pulled back - the
rubber then pulls it up kite-like. (It is NOT like a catapult launch!).
Launches of heights up to 500' can be obtained on a good day. The launching
procedure is simple - keep the elevator neutral (for now) and keep it
flying straight. At the top the glider will just fly off the line. A small
engine can also be used but it creates a lot of drag which is very
detrimental to gliding performance. Hi-starts range from around $20 for
light-weight models to $100 for heavy-duty ones.

Winches are also used - it's very similar to a high-start except that you
(the pilot) always have control over the line tension so you can usually
get better launches. It does take more skill, though; as a beginner you
don't need to worry about winches just yet.

Flying at the slope you just chuck the plane into the wind - that's it!

>How do sailplanes stay up?

Since a sailplane has no engine, it follows that it must always sink
through the surrounding air. The trick then is to find some air that's
going up faster than you'll sink through it... and for our purposes,
there are two kinds of such air:
   - air heated locally will tend to rise. The heating could be by the
     sun on a parking lot or a bonfire or a .... This is called "thermal
     soaring" - the columns of rising air are called thermals. This needs
     some skill/experience, and mostly involves smooth flying and a good
     idea of how your plane reacts. An easy way is to just follow more
     experienced fliers (some of which are birds) into them.
   - wind striking a slope will rise to go over it. You just fly in front
     of the slope where the air is going up. With a steady wind this is
     easy to fly in, with challenges provided by aerobatics etc. This is
     called (surprisingly) "slope soaring." Landing is more challenging
     while at the slope unless you have a large field or something at the
     top.

Recommendations:
Sailplanes:
   6' or 2m class: (recommended)
     Carl Goldberg Gentle Lady, Dynaflite/Craft-Air Drifter II, Airtronics
     Olympic 650, SIG Riser, Great Planes Spirit, etc. These are all
     polyhedral ships with rudder and elevator controls. All are highly
     recommended.
     Carl Goldberg Sophisticated Lady: basically a souped up Gentle Lady,
     it is in general not recommended - it's heavier and the T-tail
     structure is very easy to break, even on a slightly rough landing.
   100" or standard class:
     These models fly better but are more cumbersome to launch and transport,
     and are also slightly more expensive. Try Dynaflite/Craft-Air Butterfly,
     Airtronics Olympic II, SIG Riser 100 etc. These are basically scaled up
     versions of the 2m ships above.

Costs:

>What kind of cost am I looking at for a solid training glider or
>powered plane, with all gear?

$200 is in the ballpark. $120 for a 4-ch radio, $60 for a 2m glider,
covering and other supplies. ARF Gliders - $100 + radio + supplies.

Powered planes: about $350-400 - $120 radio, $70 plane, $120 engine + supplies.

(By "supplies," I mean things like rulers, knives etc.)

>Where can I mail-order stuff from?

Try Tower Hobbies (1 800 637 4989) and Sheldon's (1 800 228 3237) [Inside
CA, 1 800 822 1688]. Also look in modelling magazines for ads. Try Radio
Control Modeler, Model Airplane News, Flying Models, Model Aviation.

================================ End of Part 1 ==============================
-- 
This file is available by anonymous ftp from pit-manager.mit.edu
pub/usenet/news.answers/RC-flying-FAQ/part{1,2}. (Files can also be retrieved
by sending a message to mail-server@pit-manager.mit.edu with "send <fname>"
where <fname> is the name of the file.)                -- shamim@cs.arizona.edu