Impact of Aeroelastic-P ropulsive Interactions on Flight Dynamics of a Hypersonic Vehicle

Many air-breathing hypersonic vehicle design concepts utilize the lower surface of an elongated fuselage forebody to provide aerodynamic compression for a supersonic combustion ramjet module, or a scramjet. This highly integrated design approach creates the potential for an unprecedented form of aeroelastic-p ropulsive interaction in which deflections of the vehicle fuselage give rise to propulsive force and moment variations that may impact the vehicle's flight dynamic characteristics. This investigation examines the potential for such interactions using a math model that describes the longitudinal flight dynamics, propulsion system, and first seven elastic modes of a hypersonic vehicle concept. Estimates of the propulsion system sensitivity to angle-ofattack variations and modal fuselage deflections are presented and compared with predictions based on an earlier reference. The combined aeroelastic-propulsive model is used to illustrate a variation in the vehicle's longitudinal flight dynamics with the propulsion system sensitivities. Numerical values for the completed model at flight conditions of Mach 6 and Mach 10 are presented.