A Critical Speed Study for Aircraft Bias Ply Tires.

Abstract : This report describes the derivation and validation of the critical speed equation that predicts the inceptive speed of the standing wave in the tread band of aircraft bias tires. The critical speed equation is based on the classical theory of a straight beam on an elastic foundation, under tension. Derivations of relations describing each term of the critical speed equation are also presented. These relations describe the effective tire structural properties such as the tread band bending stiffness, the elastic foundation linear spring constant, the belt tension due to inflation pressure, and the tread band effective density. Dynamometer tests of a 49x17/26PR Type VII Goodyear tire was conducted to validate the critical speed equation. Trends relating critical speed with inflation pressure, tread depth, and loaded vertical deflection were correctly predicted, yielding an average of 2.9-percent error. Keywords: Critical speed, Tire dynamics, Aircraft tire, Standing wave, Tire structural properties, Traction wave.