James F. Driscoll, Arthur B. Modine Professor, Department of Aerospace Engineering, University of Michigan

Several design rules are discussed that can be helpful in optimizing the design and the ascent trajectory of a generic (X-43 like) hypersonic vehicle that is powered by a dual-mode ramjet-scramjet engine. This talk discusses some results of recent Ph.D. theses of Drs. Chukwuka Mbagwu and Chris Marley. The focus is on “vehicle integration” design rules that account for realistic constraints, including the requirement that the vehicle must be trimmed at all points along an ascent trajectory and that additive drag and vehicle stability are considered. A hypersonic waverider does not follow rules for a conventional airplane, where the goal is a large ratio of wing area to frontal area in order to maximize Lift/Drag ratio. Nor does a waverider follow rules for a rocket (where the goal is to maximize the Thrust/Drag ratio, requiring a small ratio of wing area to frontal area). Instead a waverider requires an optimization of both T/D and L/D. Parameters that were varied were: aspect ratio, engine width, chord length, acceleration and flight Mach number (M). Advantages of a Reduced Order Model (ROM) are discussed.