Hinge-moment derivatives for an oscillating control

Abstract

The semi-empirical 'equivalent profile' method of W. P. Jones (1948) is extended to the case of an aerofoil with an oscillating control. The oscillatory hinge-moment derivatives for such an aerofoil-control combination in a low-speed wind tunnel are estimated, an allowance for tunnel wall interference effects being included. A comparison with measured values of the control derivatives is made for two values of the control chord ratio, representing an aileron and a tab. The method of this report gives results in much better agreement with experiment than those obtained by vortex-sheet theory.