Abstract:
Aileron and elevator hinge-moment derivatives have been extracted from flight tests on the Fairey Delta 2 in which the dynamic aircraft response, to control pulses was recorded. As this method is not widely used, and has proved very successful, it is described in detail. Corrections had to be made for aeroelastic distortion of the control surfaces, for inertia loads acting on the controls and for the dynamic response of the instrumentation. Where possible the results are compared with wind-tunnel data. There is good agreement for the hinge moment due to control derivatives, b2, and the elevator, b1, whereas the results for aileron, b1, show differences from the tunnel values at supersonic speeds. b0 could not be measured because of strain gauge drift; however consistent results were obtained for the aileron hinge moment induced by the elevator deflection and vice versa. At transonic speeds these terms are of similar magnitude to the conventional hinge moment derivatives b1 and b2, and must therefore be considered by designers.
