Simple Heat Engines

Simple Stirling Engine

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Simple Stirling Engine: Perhaps the simplest piston engine ever devised- a single piston powered by a tiny alcohol lamp. Glass components allow a view of the internal workings of this design, and the interesting startup behavior from oscillation to full rotation. Heat engines produce mechanical motion from a difference in temperature- here the piston side is near room temperature (the central aluminum post is an excellent conductor and acts as a heat sink as the gas flows through), and the test tube is kept at high temperature via the flame, with metal fibers to help conduct the heat into the air (this component is called the regenerator). Swipe to see the elegant assembly of this model, and swipe again to see the engine power down. This external combustion design is attributed to Scottish engineer Robert Stirling back in 1816.

Tea-Light Floating Engine

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From Grand Illusions Ltd.: BUY NOW Floating Steam Engine 

Engines of similar design are used in pop-pop boats 

Tea-Light Floating Engine: a candle powered super simple steam engine. The engine is just a coil of copper tubing filled with water. Steam builds up pushing water out with an explosive jet- which then results in a vacuum in the coil which pulls more water in to repeat the process. The water expulsion is in the form of jet directed out the end of the tube whereas the refill comes back in to the tube from a larger range of angles- so on balance the engine moves opposite to the direction of the jets.