Hypersonic vehicle required aerodynamic prediction accuracy

The accuracy of aerodynamic based on stability and control considerations is presented for three classes of hypersonic vehicles. Critical flight conditions and maneuvers were selected for each of the study vehicles, and a sensitivity study was conducted at the selected critical conditions. The sensitivity study determined the effect of individual aerodynamic stability derivatives on the dynamic response of the vehicles. Unacceptable vehicle dynamic response established the aerodynamic accuracy limits. Nonlinear aerodynamic characteristics based on wind tunnel or flight test data were used in a six-degree-of-freedom digital simulation program which calculated the vehicle motion time histories for specific control inputs. The control surface inputs were provided by a simple model-following control system. Sample X-24C-10D results for individual sensitivity analyses are discussed, and sensitivity limits for the three vehicles are presented