Measurements of two-dimensional derivatives on a wing-aileron-tab system with a 1541 section aerofoil. Part 1 direct aileron derivatives

Abstract

Measurements have been made of the direct two-dimensional damping and stiffness derivatives for a 20 per cent aileron on an aerofoil with a 1541 section in incompressible flow. Corrections arising from the apparatus are discussed and reference is made to an attempt to measure the direct tab derivatives. The effects are shown of frequency parameter, amplitude of osciliation, Reynolds number, aileron angle and position of transition on the wing. Variation with frequency parameter is substantially the same as for vortex-sheet theory and variation of amplitude produces little change in both derivatives.