This one is brilliant! Have you been looking for a simple stirling engine to make without much in the way of machining skills? The instructions do call for a metal lathe, but the only part where this is truly necessary is the power piston - if you're lucky in your choice of materials you might be able to find brass stock which fits well enough inside a tube that you could do it without the lathe.
The North American Model Engineering Society (NAMES) has kindly granted permission to publish their instructions to build the NAMES Tin Can Stirling Heat Engine. Dennis Dalla-Vicenza received the the original paper instructions from a NAMES member who picked them up as a convention hand-out. Dennis has converted the document into electronic form as a PDF (Portable Document Format) file. Thanks to Dennis and NAMES (specifically Tom Stockton and Lori Niemuth) we can now all share this novel and easy to build engine design and see the Stirling Prinicpals in action.
The following text is extracted from the instructions...
This project will change your grocery shopping. The use of tin cans simplify construction. The this sheet metal walls permit rapid transfer of heat. The cans are readily modified, and if you go wrong throw the can away and use another.
This engine is not going to be pretty, but it is relatively simple to build and you will come to realize the whole design can be modified in many ways.