The FAA conducted a tire performance evaluation and friction equipment correlation study in August 1989 at NASA Wallops Flight Facility located at Wallops Island, Virginia. The study was performed in response to a request by the ASTM to evaluate the performance of tires manufactured according to specifications ASTM E524 and ASTM E670. Some 1,650 tests were conducted on five types of surfaces using three different brands of tires and four different types of friction-measuring devices. Friction tests were conducted at speeds of 40 and 60 mph (65 and 95 km/hr), using the self-water system of the device on dry test surfaces. The water was applied to a depth of 0.04 in. (1 mm). The analyses conducted involved 156 reliability and performance studies and 31 correlation comparisons. Limits of acceptability were established for the data evaluation. The McCreary tire performed best on the runway friction tester, Saab friction tester, and the skiddometer. The Dico tire performed best on the mu meter. The tire formulation given in the ASTM E524 specification for lock-wheel trailers will be put into a new ASTM standard to describe the characteristics of the McCreary tire. The present E670 specification will contain the specifications for the Dunlop and Dico tires.
Samenvatting