Analytical aeropropulsive-aeroelastic hypersonic-vehicle model with dynamic analysis

The determination of the dynamic characteristics of hypersonic vehicles requires an integrated approach since the propulsion system and airframe are so highly coupled. The forces and moments arise from both aerodynamic and propulsive sources, which are for these configurations hard to separate. Offered herein is a first step toward the development of such an approach that is intentionally generic and basic. Further, analytical expressions are developed to allow for characterization of the vehicle's dynamics early in the design cycle, so that configuration trade-offs may be performed with some cognizance of the attitude dynamics. The method of approach involves a 2D hypersonic aerodynamic analysis utilizing Newtonian theory, coupled with a 1D aero/thermo analysis of the flow in a scramjet-type propulsion system. In addition, the airframe is considered to be elastic, and the structural dynamics are characterized in terms of a simple lumped-mass model of the in vacuo vibration modes. It is shown that the vehicle's aerodynamics and propulsive forces are both very significant in the evaluation of key stability derivatives that dictate the vehicle's dynamic characteristics. The vehicle model selected is highly unstable in pitch and exhibits strong airframe/engine/elastic coupling in the aeroelastic and attitude dynamics. (Author)