This 2 Part DIY Video project shows how you can build yourself a fully working Homemade Stirling Engine out of Coke Cans and other easily available materials .The engine shown here is powered by small candles.
This engine uses air which is repeated heated and cooled. To allow the air to be heated and cooled the coke can contains a displacer which is like a loose piston that can move up and down forcing the air around the engine. When the air is heated it expands pushing the diaphragm (balloon) outward which turns the cranks. When the cranks turn they move the displacer down so that the air is near the top where it is cooled causing it to shrink and pull the cranks back, which of course moves the displacer upwards allowing the air to be heated at the bottom, this repeats over and over.The other videos shows the strling engine made in action generating electricity and powering small radios.