NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

0201-20-2301 October 14, 1955 4368

0201-20-2304

0201-20-2327

Development, Testing, and Evaluation of

Visual Landing Aids

Consolidated Progress Report

to the

Airborne Equipment Division

Bureau of Aeronautics

Department of the Navy

For the Period

July 1 to September 30, 1955

for

Bureau of Aeronautics Projects

TED No. NBS-AE- 10002

TED No. NBS-AE- 10011

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, rep

unless permission Is 25.D.C, Such pern

cal ly prepared if th

Approved for public release by the

director of the National Institute of

Standards and Technology (NIST) on October 9, 2015

n part, is prohibited

.ndards, Washington

iort has been specifiaort for its own use.

Development, Testing, and Evaluation of

Visual Landing Aids

July 1 to September 30, 1955

I, REPORTS ISSUED

Report No , Title

21P-11/55 Photometric Tests of a Modified High-Intensity

Deck-Surface Light

4219 Development, Testing, and Evaluation of Visual

Landing Aids, Consolidated Progress Report for

the Period April 1 to June 30, 1955

II. RESEARCH AND DEVELOPMENT, LABORATORY TESTING, AND

CONSULTATION SERVICES IN CONNECTION WITH VISIBILITY,

AIRFIELD LIGHTING, AND FOG MODIFICATION PROBLEMS

(TED NBS-AE- 10002).

a, Visibility Meters and Their Application,

Transmissomefers , One complete transmissometer and two additional indicators have been sent to NAS Atlantic City, A visit

was made to the station and the transmissometer in the touchdown

area was adjusted and placed in operation.

Phototubes of improved construction have been received from

the Continental Electric Company and tested. The results were quite

satisfactory. These tubes have a cathode area about one-half that

of the type now used and the anode structure has been moved to the

sides of the tube so that the image of the projector does not fall

on it. Efforts are now being made to obtain tubes of this con- struction but with a photosensitive surface with spectral response

characteristics which more nearly approximate the spectral response

characteristics of the human eye.

Individual phototubes and trigger tubes are now tested by

giving them an operational check. Since the tests of this type are

not applicable to specifications or routine inspection, a study is

being made of direct methods of testing the tubes using quantitative

measurements, A sufficient number of tubes have been evaluated to

permit the preparation of a performance specification.

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The list of pen and ink changes and the change sheets to be

used in modifying copies of the original instruction manual to

conform to the revised manual have been completed and are now

being reproduced,,

A report giving an analysis of the theory of the photometric

system of the transmissometer is being prepared,, The intent of

this report is to assist personnel responsible for the design of

installations and for the application of instruments by providing

a more complete theoretical background than was possible to

include in the instruction manual,,

Brightness Meters., Ttoo sets of photoelectric sky-brightness

meters and i lluminometers have been calibrated and tested,. The

scanning driver caused some difficulty because of weaknesses in

the gear boxes,, These were rebuilt,, After satisfactory operation

was obtained, these meters were shipped to the Areata Field

laboratory,,

b0 Airfield Lighting and Marking,

Runway Marking , A comprehensive program for the evaluation

of paints and other materials intended for use as runway markings

has been developed and coordinated with the various groups within

the Bureau which will do the testing.

Taxiwav Lighting . Intensity distribution measurements have

been made of a type M-l light with a clear asymmetric and with a blue symmetric lens. A report has been prepared.

Fueling lane Lighting . A report giving the results of intensity distribution measurements of a Doane high-intensity decksurface light and an analysis of these measurements has been

completed and released, (NBS Report 21P-11/55)

Control of Constant-Current Regulators . To prevent failure of all

lamps in a series circuit as lamps fail and the output current rises,

a safety circuit which will put constant current regulators

on brightness step 4 when the current on step 5 would exceed 6.8

amperes has been designed and the necessary controls ordered. The

system will be tested at Areata.

Heliport Lighting , An approach-angle light has been received

from Forway Industries Inc. It is scheduled for tests starting

October 17.

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e. Seadrome Lighting.

Norfolk Installation . Assistance has been given representatives of the Visual Landing Aids Section in the planning of a seadrome lighting system for NAS„ Norfolk,, Efforts are being

made to obtain 2O-ampere 0 500-watt 0 series-burning lights for

this purpose 0 These lights would have a beam pattern similar to

that of the 350 PAR and 399 PAR approach light lamps.

Development of Hiqh-Intensitv Seadrome Lights , The principal

tasks under this project are two aspects of the problem of improving seadrome lights; the development of an optical system for

cable-fed seadrome lights,, and the development of a circuit for

battery-operated buoy lights which may be turned on or off by a single pulse 0 probably through use of a polarized relay,, For this

latter task the components of four seadrome lights are now on hand

but no laboratory work has been started.

The problem of the cable-fed buoy light has been discussed

with the engineers of the Bureau of Aeronautics and it has been

decided that the first design should aim at an aviation green

light of not over 500 watts consumption. A study of mercury lamps

is under way. Such lamps have high efficiencies in lumens per waft

and the light is greenish in color. A filter has been found which

will correct the mercury light to conform with the definition of

aviation green and the transmission of this filter for mercury

light is now being computed. This problem has also been discussed

with an engineer of the General Electric Go. 0 who has indicated

that it may be possible to increase the efficiency of mercury lamps

in this application by the use of a frequency of about 500 cycles

per second.

d. Carrier Lighting.

The equipment for controlling the wave-off lights of the mirror

landing aids system has been received and assembled for test. These

tests revealed that the action of the mercury relays Intended to

flash the wave-off lights was too slow because of the incorporation

of vibration dampers in these relays. Relays without vibration

dampers have been ordered. A visit was made to the U„S„S„ Bennington

and details of the wave-off system were discussed. Following these

discussions the control circuitry was revised to adapt it to the

other circuitry now on the mirror system. ‘Two sets of the control

equipment will be wired and shipped to the Bennington as soon as the new relays are received. On numerous occasions technical advice

and assistance has been given to representatives of the Navy and

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of contractors in the design of improvements to the mirror landing

aids systems,,

e. Lighted Suit for Landing Signal Officer„

Braided wire for the light strips on the LSO lighted suit

equipment has been investigated,, It is expected that the strips

will be fabricated as extruded plastic with the braid imbedded

inside 0 Reports from users of the Model 0 equipment indicate that

failure of the braided wire within the rubber strips has been more

of a problem than was anticipated,. Accordingly various samples of

braid have been life tested on a flexing machine,, and it was ascertained that a braid consisting of about 150 strands of No. 40 gauge

wire should provide durability superior to the coarser braid used

on the Model 0 equipment,, but that the strips will nevertheless

have limited life*

A specification is in preparation for use in procurement of

the new equipment* If a loose specification will be adequate, then

the specification will be completed in about 6=8 weeks* If a tight specification is required, then several months will be

necessary to resolve several questions relating to the design of some of the components of the equipment. The decision as to which

kind of specification will be required is to be made by the Bureau

of Aeronautics -within 1-2 weeks.

f. General Laboratory and Consultive Services.

Specific Intensity Measurements of Retroreflectors. Measurements of the specific intensity of a group of colored retrorefleetors have been checked. A report giving the results of specific

intensity measurements of 21 colored retroreflective samples has

been completed and is being prepared for reproduction.

Cable Test-Detecting Set. The laboratory tests of this unit

have been completed and the set has been sent to the Areata Field

Laboratory.

Kinorama . The following persons have inspected the kinoramas

Col. H. J. Holt and Col. A. J. Hill of the Military Agency for

Standardization. Arrangements for the use of the

kinorama for intercomparing approach-light configurations in connection with an Air Force-Civil standardization are under consideration.

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Lieut. R 0 Gross of Wright Air Development Center, The kinoraraa was considered as a training device for Air Force

pilots. It will not be used under their present

contracts.

Dr, C, P, Seitz and Dr, H„ A, Voss of the Naval Special Devices

Center, The use of the kinorama for a general study

of approach-light configurations is being studied,

Mr, R„ P„ Snodgrass,, Engineering Department Head for Flight

Research at the Sperry Gyroscope Co, The use of the

kinorama for flight research was considered. There was a generally favorable reaction but no specific

proposals.

Col, J, F, Taylor, Director of the Air Navigation Board 0 flew

the kinorama to become’ acquainted with the possibilities of the device. Further demonstrations have been

requested,

III, VISIBILITY AND BRIGHTNESS TESTS, SURVEYS, EVALUATION AND ANALYSIS OF VISUAL LANDING AIDS, BASIC

TESTS AND EQUIPMENT AS A FIELD SERVICE AT ARCATA,

CALIFORNIA (TED NBS-AE- 10011)

.

a. Airport Lighting and Marking,

Approach Beacons, Arrangements have been made to obtain the

assistance of CAA maintenance and flight test personnel in checking

the effects of the approach beacon to be installed at the end of

runway 13 as part of a stub approach beacon system on the localizer

of the ILS system. Because of the bluff in this area, it will be

necessary to mount the approach beacon only 75 feet from the

localizer. Preliminary checks showed that there was interference

with the localizer beam pattern. Since problems similar to this

are expected at other airports, this work will be of general rather

than only local value. Southwest Airways and the Humboldt County

Department of Airports are considering installation of a standard

approach-beacon system at Crescent City as a result of their experience with the experimental system at Areata, The installation will

provide more pertinent flight data than the Areata installation

since there is no approach-lighting or instrument-landing system at

Crescent City, Five beacon bases have been obtained from the CAA

and the other fixtures necessary for test installations at Areata

have been obtained.

Airfield Lighting Maintenance Manual- The step-by-step

trouble-shooting procedure and the trouble-shooting charts have

been revised and are now being put in final form. The section

on general trouble-shooting procedures for series and parallel

circuits has been outlined,, The first draft of the part covering

series circuits is nearly complete,, This section is intended to

give the general and detailed information needed for trouble

shooting so that a minimum of text and detail is required in the

step-by-step procedures,.

Regulators. Three type NC-3 regulators have been obtained

from Navy stock and installed in the runway lighting circuits

These regulators will be used for tests of over-current prote©*-

tive devices,, studies of optimum intensity of runway lights,, etc.

b. Electrical Engineering.

Cable-Fault Finding . The TSM-11 Test Set has been received

and is being tested. A number of problems have been found in the

application of the instrument to circuits having multiple grounds,,

lines in sheath or duct buried in soil of poor conductivity,, and

lines of varying depth. These problems are inherent in the use of any instrument operating on the same principles as the TSM-11.

Methods of using the set under these conditions will be developed

and notes to be added to the instructions for using the instrument

will be prepared.

Induced Voltages. A study is being made af the effects of

induced voltages in control cables using the cables to the slant

visibility meter for the tests. Considerable difficulty in the

operation of relays was encountered because of strong voltages

on this cable. The relay coils were shunted with lamps or re- sistors to obtain satisfactory operation. Use of incandescent

lamps is particularly advantageous since they present a low shunt

resistance to the stray voltages,, since these do not heat the

filament to incandescence, and a much higher resistance to the

control voltages,, since the lamps are then hot.

With this cable completely disconnected, some stray voltages

were present. When some of the conductors are connected to the

equipment, the voltages are increased. Checks are now being made

to see what part of these stray voltages result from leakage between conductors and what part is the result of capacitive or inductive coupling.

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c. Research on Visibility Measurements and Visibility.,

Skv Brightness. The sky brightness meters and illuminometers

have been received from Washington., Tentative sites and plans for

the needed control and signal cables have been determined., It

is planned to install the two sets about 3000 feet north and 3000

feet south of the laboratory and to put all the recording instruments in the laboratory,, A concrete pier has been constructed in

the laboratory to provide a stable„ vibrationless support for the

self-balancing potentiometers.,

Slant Visibility. Meter.. A recording amplifier which will

operate a 5 ma Esterline-Angus recorder was designed,, constructed,

and calibrated in Washington and has been installed to record

the ceilometer output., The instrument is operating satisfactorily.

The sensitivity is very high and the stability is very satisfactory.

Some modifications have been made in the circuitry of the scanning

drive and the reversing switch in the scan-drive motor has been

replaced with external relays to protect the starter winding of

this motor. The projector lamp life has been quite variable.

Some lamps last weeks, others only a few days.

Transmis some try . Considerable data have been obtained on the

magnitude of the error produced by light from the projector being

scattered into the receiver. Measurements have been made in fogs

with transmissions as low as 0.0007, using a receiver aperture

of 3.5 inches. An error of about 0.0002 was found in this fog.

The error is about 0.001 when the transmission is 0.1, 0.0005 when

the transmission is 0.01, and 0,0002 when the transmission is

0.001. None of these errors has a significant effect on the indicated visual range. Measurements are now being made with a receiver aperture of 2.5 inches.

Equivalent Intensity of Flashing Lights and of Composite Units . Reports giving the results of measurements of the effective intensity of a Sylvania Strobeacon and a composite unit are now nearly complete. Plans are being made to study the effective intensity of a Westinghouse Krypton light. The unit has been checked

and found to be inoperative because of either a defective igniter

coil or lamp.

Facilities . Most of the present overhead circuits between the

control tower and the vault have been transferred to the new underground cable which was installed when the CAA was installing cables

between these points. This addition provides sufficient cable for some expansion and provides access to the controls of the visual

aids at the field.