1 American Institute of Aeronautics and Astronautics Quasi-1D Aero-Thermodynamic Flowpath Modeling of an Inversely Designed Morphing Hypersonic Engine Vol 1 Mookesh Dhanasar (mdhanasar@gmail.com), 1 Frederick Ferguson, 2 , Nastassja Dasque, 3 and Leonard Uitenham 4 Center for Aerospace Research, NCAT, Greensboro, NC 27411, USA Isaiah M. Blankson 5 NASA Glenn Research Center, Cleveland, OH, USA Encouraged with the successful testing of the X-51A/SCRAMjet Engine Demonstrator concept, there continues to be interest in the development of the Dual-Mode scramjet as a promising high-speed air-breathing hypersonic engine. In contributing to that effort the work described herein builds on the authors previous works on this subject area. Focus in this paper is on the development of a quasi 1D model which will be used to; (1) attempt to validate the performance of the morphing dual mode scramjet, and (2) used as a base for the development of models of greater complexity. Initially the geometric and aerodynamic models for the forebody section of the morphing hypersonic engine are developed using an inverse design approach. For this particular design phase a total of three inputs (freestream velocity, wedge angle and wedge length) are used to generate the appropriate geometric and aerodynamic models. Next information obtained from the forebody section is used in the development of the quasi 1D model for the combustor-nozzle section of the morphing scramjet engine. The quasi 1D combustion model is developed using four fuels. These fuel are (1) a propane-methane mixture, (2) a propane-hydrogen mixture, (3) a methane-hydrogen mixture, and (4) a hydrogen fuel. Nomenclature  = waverider caret angle, angle of attack  = shock wave angle V = freestream velocity L = Wedge/shock generator length D h = Isolator hydraulic diameter d hf Fuel injector hydraulic diameter  = specific heats ratio H ∞ flight altitude M = Mach number  = wedge angle M c = Convective Mach number U f = Velocity of fuel 1. Introduction ASA is currently engaged in research to develop low-cost alternatives for access-to-space and novel new concepts for high Mach number propulsion. Air-breathing access to space using combined-cycles or combined cycle engines concepts are currently being investigated as a future replacement for conventional chemical rockets. The niche for the development of high speed air-breathing engines lies in the fact that an air-breathing engine uses the oxygen present in the atmosphere. As such there is no need for the engine to carry its oxidizer supply. This fact 1 Post Doctoral Scholar, Mechanical Engineering Department, NCAT, and AIAA Member. 2 Professor & Director, Center for Aerospace Research, NCAT and AIAA Associate Fellow. 3 Ph.D. Candidate, Mechanical Engineering Department, NCAT, and AIAA Student Member. 4 Professor, Chemical Engineering Department, NCAT, and AIAA Member. 5 Senior Technologist, NASA Glenn Research Center and AIAA Associate Fellow. N