- A Stirling engine is a heat engine that operated by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levels such that there is a net conversion of heat energy to mechanical work. The engine is like a steam engine in that all of the engine's heat flows in and out through the engine wall. - Description: Speed: 1500 to 1700 RPM; - Features: Using mold steel manufacturing, solid and firm; Flywheel is fine and elegant; Rod is made of stainless steel