NATIONAL BUREAU OF STANDARDS REPORT

4565

STATIC LOADING TESTS OP

A. G. A. EXPENDABLE TOP RUNWAY LIGHT HEAD ASSEMBLIES

WITH GLASS COVERS

by

L® K« Irwin

Report to

Wright Air Development Center

Department of the Air Force

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards is suggested in the following listing

of the divisions and sections engaged in technical work. In general, each section is engaged in

specialized research, development, and engineering in the field indicated by its title. A brief

description of the activities, and of the resultant reports and publications, appears on the inside

of the back cover of this report.

Electricity and Electronics. Resistance and Reactance. Electron Tubes. Electrical Instru- ments. Magnetic Measurements. Process Technology. Engineering Electronics. Electronic

Instrumentation. Electrochemistry.

Optics and Metrology. Photometry and Colorimetry. Optical Instruments. Photographic

Technology. Length. Engineering Metrology.

Heat and Power. Temperature Measurements. Thermodynamics. Cryogenic Physics.

Engines and Lubrication. Engine Fuels.

Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid

State Physics. Electron Physics. Atomic Physics. Nuclear Physics. Radioactivity. X-rays. Betatron. Nucleonic Instrumentation. Radiological Equipment. AEC Radiation Instruments. Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry.

Inorganic Chemistry. Electrodeposition. Gas Chemistry. Physical Chemistry. Thermochemistry. Spectrochemistry. Pure Substances.

Mechanics. Sound. Mechanical Instruments. Fluid Mechanics. Engineering Mechanics.

Mass and Scale. Capacity, Density, and Fluid Meters. Combustion Controls.

Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer Structure. Organic Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion.

Mineral Products. Porcelain and Pottery. Glass. Refractories. Enameled Metals. Concreting Materials. Constitution and Microstructure.

Building Technology. Structural Engineering. Fire Protection. Heating and Air Conditioning. Floor, Roof, and Wall Coverings. Codes and Specifications.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics.

Data Processing Systems. Components and Techniques. Digital Circuitry. Digital Systems.

Analogue Systems.

Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials.

Gas Liquefaction.

Radio Propagation Physics. Upper Atmosphere Research. Ionospheric Research. Regular

Propagation Services.

Radio Propagation Engineering. Frequency Utilization Research. Tropospheric Propagation

Research.

Radio Standards. High Frequency Standards. Microwave Standards. • Office of Basic Instrumentation • Office of Weights and Measures
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

0201-20-2331 March 1956 1+565

STATIC LOADING TESTS OP

A, Ge A„ EXPENDABLE TOP RUNWAY LIGHT HEAD ASSEMBLIES

WITH GLASS COVERS

by

L e K. Irwin

Engineering Mechanics Section

Mechanics Division

To

Equipment Laboratory

Wright Air Development Center

Department of the Air Force

NBS Labo No. 6.4/2-1+-2

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, r, Approved for public release by the

unless permission i director of the National Institute of

25 ,d.c. Such pe standards and Technology (NIST)

cal ly prepared ifl on October 9, 2015

' in part, is prohibited

tandards, Washington

sport has been speclfieport for its own use,

STATIC LOADING TESTS OP

A. Go A, EXPENDABLE TOP RUNWAY LIGHT HEAD ASSEMBLIES

WITH GLASS COVERS

by

L* K, Irwin

lc SAMPLES

Pour expendable top runway light head assemblies with

glass covers s manufactured by the American Gas Accumulator

Division, Elastic Stop Nut Corporation, were submitted for

static load tests. The light head assemblies represented

parts of a prototype runway marker light. Glass covers

were furnished 3/4 inch thick for two assemblies and 1 inch

thick for two assemblies. The 7 inch diameter glass plate

in each assembly, seated on a silicone rubber and fiber

glass gasket, was retained in the mounting ring by flexible

waterproof adhesive.

2. TESTS AND PROCEDURES

Por two tests, the light head assemblies were placed

in the center of the lower platen of a testing machine and

compression loads were applied through a 20x4»4j 10-ply

rating, aircraft tire. The laboratory set-up of sample

A-3/4" and the aircraft tire is shown in figure 1. The

air pressure in the tire at no load was measured to be 1^5

Ib/inf

Three tests were made with the aircraft tire replaced

with 7 inch diameter hardwood or steel discs. A pad of

3/16 inch thick rubber was placed between the discs and the

glass plates to provide more even load distribution.

3. RESULTS

Five static load tests were made on three A. G. A.

expendable top light head assemblies. The results of these

tests are given in table h

NBS Labo No. 6 .4/2-4-

page 2

Table 1 - Static Load Tests of A. G. A. Expendable Top

Light Head Assemblies*

Sample

and

test No.

Loading

medium

Maximum

load( L)

L

A* Remarks

lb lb/in?

a-3A"-i 20x4*4

tire

9,000 - No visible

damage

-2 hardwood

disc and

rubber pad

21,000 546 No visible

damag e

-3 steel disc

and rubber

pad

31,700 824 Gasket extruded

toward center

of glass plate

B-3/V-1 steel disc

and rubber

pad

32,900 855 Gasket extruded

toward center

of glass plate

A-l”-l 20x4*4

tire

9,000 - No visible

damage

1

—

t

CQ No mechanical tests performed

*A = area of upper surface of glass plate

Sample A-3/4” is shown in figure 2 sustaining a load of

9,000 lb applied through the 20x4<>4 tire* Visual examination

of the assembly during and after this test did not indicate

damage. Compressive loads of 31,700 lb and 32,900 lb applied

to samples A-3/V' and B°3/4% respectively, caused the silicone rubber and fiber glass gaskets to be extruded toward the

centers of the glass plates and simultaneously there were

marked decreases in the loads being sustained by the assemblies, No additional loads were applied. The glass plates,

mounting rings and damaged gaskets are shown in figures 3 and

4 after tests A~3/4n ”3 an d B“3/4M ~ls> respectively.

For the Director,

B, L, Wilson, Chief,

Engineering Mechanics Section,

Washington, D. C. Division of Mechanics.

March 1956

Laboratory set-up for compression test of

sample A-3/V' with a 20xi|..[|. aircraft tire.

6.4/2-ii-2 Figure 1

Sample A- 3A" with a load of 9,000 lb

applied through the 20x4A tire.

6. 4/2-4-

Figure 2

6.k/2-k-Z

Sample A-3/V after a maximum load of 31»700 lb.

Note the broken threads of the gasket in the

lower left quadrant.

Figure 3

r V.

6. 14-/2-14.-

Sample B- 3/I4." after a maximum load of 32,900 lb.

The gasket appears to be damaged around approximately one-half the circumference of the glass

plate. Figure I4

.

THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods

for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials,

devices, and structures; advisory services to Government Agencies on scientific and technical

problems; invention and development of devices to serve special needs of the Government; and the

development of standard practices, codes, and specifications. The work includes basic and applied

research, development, engineering, instrumentation, testing, evaluation, calibration services, and

various consultation and information services. A major portion of the Bureau’s work is performed

for other Government Agencies, particularly the Department of Defense and the Atomic Energy

Commission. The scope of activities is suggested by the listing of divisions and sections on the

inside of the front cover.

Reports and Publications

The results of the Bureau’s work take the form of either actual equipment and devices or published papers and reports. Reports are issued to the sponsoring agency of a particular project

or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Government Printing Office: The Journal of Research, which presents

complete papers reporting technical investigations; the Technical News Bulletin, which presents

summary and preliminary reports on work in progress; and Basic Radio Propagation Predictions,

which provides data for determining the best frequencies to use for radio communications throughout

the world. There are also five series of nonperiodical publications: The Applied Mathematics

Series, Circulars, Handbooks, Building Materials and Structures Reports, and Miscellaneous

Publications.

Information on the Bureau’s publications can be found in NBS Circular 460, Publications of

the National Bureau of Standards ($1.25) and its Supplement ($0.75), available from the Superintendent of Documents, Government Printing Office. Inquiries regarding the Bureau’s reports and

publications should be addressed to the Office of Scientific Publications, National Bureau of

Standards, Washington 25, D. C.