To increase the technology readiness level of hypersonic scramjet technology, an innovative strut-based dualmoderamjetenginedesign capableofpoweringa hypersonicvehicleatspeedsfrom Mach4to 8isinvestigated.Two versions of the engine are under development: a dual-mode (ramjet/scramjet )engine formissile applicationsand a rocket-based combined cycle engine for space access. This paper will discuss the features of the dual-mode engine design and how they contribute to overall engine performance. Engine component performance was evaluated using a combination of analysis and component testing. Inlet performance data (mass capture, pressure recovery, and inlet/isolator pressure ratio ) were obtained from wind-tunnel testing and correlated with model and full-scale computational e uid dynamics (CFD)analyses. Combustorperformance data (combustion efe ciency, fuel-injection performance, and pressure distributions ) were obtained from full-scale direct-connect combustor testing. Nozzle losses and efe ciency were obtained from CFD analysis. Performance parameters derived from these component tests and analyses were fed into a standard hypersonic engine cycle code to predict e ight engine performance. The demonstrated component performance values were extrapolated to determine predicted component performance at the end of engine development, which were used to compute the vision e ight engine performance.