Flight measurements of the elevator and aileron hinge moment derivates of the Fairey Delta 2 aircraft up to a mach number of 1.6, and comparisons with wind tunnel results

Aileron and elevator hinge moment derivatives have been extracted from flight tests on the Fairey Delta 2 in vrhich t he dynamic aircraft response to control pulses was recorded. As t his 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.