' NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

0201-20-2301

0201-20-2327

July 1, 1954 3377

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

April 1 to June 30, 1954

for

Bureau of Aeronautics Projects

TED No. NBS-AE- 10002

TED No. NBS-AE- 10006

TED No. NBS-AE- 10007

TED No. NBS-AE- 10008

TED No. NBS-AE- 10011

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U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, repri

unless permission Is ot 25, D, C. Such permi

cal ly prepared If tha

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 2015

part, is prohibited

idards, Washington

irt has been specifiort for its own use,
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Development, Testing, and Evaluation of Visual Landing Aids

April 1 to June 30, 1954

I. REPORTS ISSUED

Report No.

3242

3260

21 P-4/54

21 P-5/54

21 P-6/54

Development, Testing, and Evaluation of Visual Landing

Aids, Consolidated Progress Report For the Period

January 1 to March 31, 1954

Report of a Survey of Visual Landing Aids

Memorandum Report of a Study of the Visual Range of

Radio and Television Towers; Section I, Visual Range

of Tower Structure and Guy Wires

Addendum to Memorandum Report of a Study of the Visual

Range of Radio and Television Towers Dated May 20, 1954

Memorandum Report of a Study of the Visual Range of

Radio and Television Towers; Section II, Visual Range

of Obstruction Lights and Hazard Beacons

Photometric and Battery-Life Tests of a Model Light for

Night Field Carrier Landing Practice

Effects of Lamp Position on Beam Setting and Visual

Range of Type C-l Runway Light

Photometric and Life Tests of Eight Approach-Light Lamps

II. TED No. NBS-AE- 10002. MISCELLANEOUS SERVICES IN CONNECTION

WITH FOG MODIFICATION AND VISIBILITY STUDIES

Beam Setting of Type C-l Runway Light . NBS Test Report 21 P-5/54 covering this work has been released. This study indicates that changing

the beam setting of Type C-l runway lights will improve the coverage on wide runways during periods of low visibility but that a wider beam

spread is required for extreme conditions.

Lights for Night Field Carrier Landing Practice . NBS Test Report

21P-4/54 has been released. This report contains photometric measurements of a light consisting of a small Fresnel lens using several

different flashlight lamps as sources, and results of battery-life

tests.
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Photometric measurements of a breadboard unit using a precision

die-cast 1 1/2-inch diameter parabolic reflector, a 100° horizontal

spread lens and several vertical spread lenses, have been made and a report has been drafted. This unit appears to be much more satisfactory than the Fresnel unit. Several simple light units have been

constructed and calibrated for use in a contemplated field test at the

Naval Air Test Center to check our determination of the optimum intensity for lights for night field carrier landing practice. (NBS Test

21P-11/54)

Characteristics of Retroref lectors . Some additional data has been

taken at large angles of divergence because of the application of

retroreflectors to taxiway marking. The data obtained to date have

been tabulated and the first draft of the report describing the work

has been completed.

III. TED No. NBS-AE-10006. DEVELOPMENT OF TRANS MI SSOMETERCEILOMETER INTENSITY CONTROL SYSTEM

Specifications . Further assistance has been given the Aerology Section, Bureau of Aeronautics, in the preparation of an interim specification for transmissometer procurement. The completed specification

has been checked.

Intensity-Setting Indicators . Following a study of the feasibility of

using in the control tower at Patuxent River a meter specially calibrated to indicate the proper intensity of approach and runway lights,

a search was made for a source of supply of a meter with a nonlinear

(preferably a logarithmic) scale. A source of a suitable type of

meter has been found and meters have been ordered.

100% Setting Calibrator . Laboratory and field tests of calibrators

have continued. They indicate that there is sufficient accuracy and

stability of the calibration of the unit for the purpose, provided

that the operational procedure takes into account the vagaries of

barrier-layer photocells.

IV. TED No. NBS-AE- 10007. RESEARCH ON VISIBILITY AND INTENSITY

CONTROL OF VISUAL LANDING AIDS

Marking of High Towers and Tall Structures . Three memorandum reports

giving the results of a study of the visual range of radio and
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television towers under day, twilight, and night conditions have

been prepared, presented, and interpreted before the ACC/AGA Ad Hoc

Group. These data were the basis for deciding if towers were

adequately marked.

Special Ceilometer . Work on this task has been postponed for

several months because of the pressure of qualification test and

other work. It was possible to resume work late in the quarter.

Work has been started on the electrical controls of the scanning

drive. Suitable circuits have been developed; the necessary relays

and switches have been ordered; limit, synchronizing, safety and

reversing switches are now being installed and the scanning drive

is being wired.

V. TED No. NBS-AE- 10008. DEVELOPMENT AND TEST OF

SEALED-REFLECTOR APPROACH- LIGHT LAMPS

NBS Test Report 21P-6/54 giving the results of tests of eight

preproduction samples of 399-watt approach-light lamps manufactured

by the Westinghouse Electric Corporation has been released. These

lamps met the requirements of the procurement specification.

Tests of ten similar lamps from the production run have been

made. These lamps failed by a small amount to meet the vertical

beam spread requirements at horizontal angles of ±15°. The lamp

life was, however, considerably longer than that specified. A

report covering this work is being prepared. (NBS Test 21P-12/54)

Photometric measurements have also been made on some 25-volt,

350-watt lamps. This data and that obtained using the 115-volt

lamps will be used in preparing a specification.

VI. TED No. NBS-AE- 10011. FIELD SERVICE OPERATION

Survey of Naval and Marine Air Stations . NBS Report 3260, "Report

of a Survey of Visual Landing Aids" has been completed and released. This report presents the results of a survey of eleven

Naval and Marine Corps Air Stations located on the East Coast.

Particular attention was given to airfield lighting difficulties

and maintenance.

Field Maintenance Manual for Airfield Lighting Systems . This task

has been given priority during the quarter. The first draft of a complete step-by-step trouble-shooting procedure has been completed and trouble-shooting charts have been prepared.
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Approach Beacon . High-intensity range lights have been installed

at the runway threshold, completing this installation so that it is

now ready for flight testing. 600-watt landing lights with green

filters are being used for the range lights pending the receipt of

course-light fixtures from the CAA,

Transmissometrv and Visibility . Comparative visual range measurements have been made in fog

of two 25-candle lamps, one unshielded and one shielded so that

only the light emitted in the direction of the observer .is allowed

to escape. There are times at night when the glow surrounding

the bare lamp can be seen farther than the direct light from either

lamp. The distances at which the direct light from the two lamps

can be seen are essentially the same.

A calibration box has been constructed for use in checking the

calibration of the 100% Setting Calibrator. When suitable operational precautions are taken, the instrument will have an accuracy of 2%.

Further data have been obtained on the effects of scattered

light on transmission measurements. The amount of scattered light

received in the system appears to increase as the transmission decreases, to reach a maximum, and then to decrease as the transmission

becomes still lower.

An illuminometer obtained on loan from the Weather Bureau has

been installed. This instrument provides a continuous record, during

daylight, of the illumination on a horizontal plane, A brightness

meter to provide a continuous record of the brightness of the north

horizon sky has been installed. This instrument was assembled from

spare NBS transmissometer components.

Tests in Fog . Several fogs of short duration have occurred during

this period, during which tests of the types described previously

were conducted.

Future Work . No changes in the course of the work are anticipated

during the next quarter.