speed up to 180-200 RPM Start temperaure difference:20 oC Colour:Silver Bottom Gold Flywheel Material :steel and Glass Size:100X100X120mm Weight:250 Grammes Warning: 1.ONLY use pencil powder to lubricate this stirling engine if need. 1.ONLhibit to add oil to lubricate. Because the oil will mix with dust in the air, and become a oil-dirt, finally make the friction to be even bigger. The stirling engine can't run freely. What is the stirling engine. A Stirling engine is a heat engine that operates 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 1.ONL engine is like a steam engine in that all of the engine's heat flows in and out through the engine wall. How it works. This is traditionally known as an external combustion engine in contrast to an internal combustion engine where the heat input is by combustion of a fuel within the body of the working fluid. Unlike the steam engine's use of water in both its liquid and gaseous phases as the working fluid, the Stirling engine encloses a fixed quantity of permanently gaseous fluid such as air or helium. As in all heat engines, the general cycle consists of compressing cool gas, heating the gas, expanding the hot gas, and finally cooling the gas before repeating the cycle. You can put the stirling motor toy in top of hot water to make the temperature difference. You also can put it in top of ICE to get the termperature difference, Just enjoy the toy!