Lightweight high performance engines capable of operating on multiple fuels are a strategic requirement for Remotely Piloted Aircraft (RPAs). Seals for reciprocating piston engines are of particular importance. Heretofore, very lightweight all carbon-carbon (C-C) composite engines in a ring-less piston configuration were developed, fully demonstrated and utilized in lightweight vehicle racing. This concept is being upgraded into an advanced hybrid composition C-C composite built into a simulated reciprocating engine with demonstration of engine operation with a ring-less piston, requiring no lubrication, providing wear resistance, and oxidation resistance at the engine equilibrium operation without the necessity for applying cooling. Optimized composite compositions will be developed utilizing sample testing for coefficient of friction, wear, strength and oxidation resistance to down-select to a composition to build and operate a simulated reciprocating ring-less piston engine during Phase I.