The Elastic Response of Bias-ply Aircraft Tires to Braking Forces

Book excerpt: A study was made to evaluate the elastic behavior of a braked rolling tire and to relate this behavior to the tire characteristics obtained from simple static flexure tests. The study consisted of static and braked-rolling tests of two types of bias-ply aircraft tires and an analysis which related tire reaction to the braking forces. The results of this investigation indicate that the elastic response of an aircraft tire to braking forces can be defined by the displacement distribution along the tire periphery and by the fore-and-aft spring constant. Changes in the rolling radius due to braking can be predicted with reasonable accuracy from elastic measurements of the static free-tread periphery or from elastic measurements within the footprint during low-speed braking, assuming there is no slippage between the tire and the pavement. The results of these tests further indicate that what was heretofore considered as pure tire slippage under braked-rolling conditions may be wholly or in part the result of tire elasticity. The elasticity must be considered in the design or application of efficient automatic braking systems.