Accession Number : ADA800137

Title :   Tests for Determining the Coefficient of Friction of 44 in. Smooth Contour Tires on Concrete Runways

Descriptive Note : Memorandum rept.

Corporate Author : AIR MATERIEL COMMAND WRIGHT-PATTERSON AFB OH

Personal Author(s) : Allen, R G ; Creech, W T

PDF Url : ADA800137

Report Date : 27 Feb 1948

Pagination or Media Count : 45

Abstract : Purpose: To determine the friction characteristics of rubber on concrete at various rubbing speeds and under heavy loading. Conclusions: That the subject method of measurement is a practical means of obtaining values for determining the coefficient of friction of aircraft tires at high speeds and high loadings. That on dry concrete runways, the skidding coefficient of friction varies from a maximum of 0.63 to a minimum of 0.32 and decreases with increase in aircraft speeds and loads. Figures 1 and 2 Appendix 5. Additional test work will be required before definite conclusions as to the specific variations may be drawn. The coefficient of friction values for the point of pending s were very erratic and were not plotted. The value of the coefficint of friction at this point was generally higher than that for the actual skid values. This is to be expected, however, the erratic nature of the readings will be checked during future skid tests with an A-26 type taxi vehicle. A marked discontinuity in the coefficient of friction vs. speed curve was noted in the range of 90-115 mph. A similar variation was noted during inertia drag load studies on the 110 S.C. tire and described in Memorandum Report No. TSEAL-24263-46-4 Addendum 1. Data obatained from the subject test confirms the hypothesis that a definite change of the surface tread rubber occurs within this speed range. Recommendations: An A-26 type taxi test vehicle will be obtained to verify and supplement the above results and to extend the range of tests to higher speeds and loads. The A-20 type vehicle used in the subject test would not exceed 100 mp with a 6000 pound load. Additional tests will be run at higher loadings and speeds with the A-26 type taxi vehicle on different types of surfaces.

Descriptors :   *AIRCRAFT TIRES, CONCRETE, FRICTION, INERTIA, RUBBER, RUNWAYS, SKIDDING, TEST AND EVALUATION, TREADS, VELOCITY

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE