FLYING QUALITIES OF RE-ENTRY VEHICLE WORST CASE ANALYSIS AND INERTIAL ROLL COUPLING

Abstract Flying qualities of re-entry vehicle deal both with trim and stability characteristics. Basically, longitudinal and lateral requirements are expressed on open loop uncontrolled vehicle and are used in the frame of shape design. They ensure controllability and trimmability of the vehicle. For flying qualities longitudinal and lateral motions are supposed decoupled but inertial roll coupling may appear in case of roll reversal manoeuvres and yield to divergence in pitch or yaw. Furthermore, many uncertainties exist on aerodynamic parameters or flight conditions and definition of worst cases is always a great challenge. This paper focuses first on validation of flying quality longitudinal and lateral stability criteria and related worst case definition via μ-analysis. Then a new criterion ensuring no inertial roll coupling will appear is defined and worst case analysis are applied to check this criterion on a practical application.