Modern Methods of Aircraft Stability and Control Analysis

This report presents new methodologies and results in the study of aircraft stability and control, including detailed consideration of piloting effects on the aircraft's motion. The potential for departure (i.e., loss of control) in transonic and supersonic flight is addressed using linear, time- invariant dynamic models which incorporate longitudinal-lateral-directional coupling. A method for designing departure-prevention command augmentation systems (DPCAS) is developed and is applied to the subsonic model of the F-14A aircraft. This design technique can provide excellent flying qualities for the aircraft throughout its flight envelope. A multivariable limit cycle analysis technique (MULCAT) is used to predict possible self-induced nonlinear oscillations, and the results of this prediction are evaluated using a direct simulation of the nonlinear dynamic model.