Wind tunnel dynamic flying study of the pitching moment derivatives of the Standard Dynamics Model in active control

This paper presents the results of a dynamic wind tunnel flying study of the pitching moment coefficients of the Standard Dynamics Model as a function of angle-of-attack, ranging from about -10 deg to +30 deg. The fully instrumented model, with its servoed elevator, has been flown in a single-pitch degree-of-freedom at low speeds under moment trim conditions covering both the stable CG locations of 19.2 percent, 25 percent, and the unstable CG location of 35 percent of mean aerodynamic chord. In the unstable case an active control law has been invoked to fly the model in an angle of attack control mode. The freely flying model has been disturbed with flight testlike inputs, and the responses have been analyzed to generate the aerodynamic pitching moment coefficients using a maximum likelihood estimation procedure. The analysis includes the closed loop active controlled system parameter estimation and the results are compared with the available SDM pitching moment data