LiquidPiston Inc. (LPI) and the University of Wisconsin - Madison propose to investigate the technical, scientific, and commercial viability of applying LPI's patented thermodynamic cycle and rotary "X" engine architecture as a hybrid-electric propulsion system to support Group 3 eVTOL SUAS as well as Urban Air Mobility (and "Orbs"). Specifically, 1) the team will investigate and optimize through advanced 3D CFD modeling the combustion characteristics of the X engine at altitude; 2) explore the architecture and application of a small <50 hp base X engine coupled within a hybrid electric propulsion system to support Group 3 UAS; and 3) explore the scaling of the proposed propulsion system to 200-500 hp to support UAM / Orb eVTOL vehicles. The team will conduct customer discovery within the Air Force, and will also leverage its commercial networks to strengthen and develop a teaming strategy to support Phase II and eventual acquisition efforts applying this dual use technology within both commercial and defense sectors.