In 1816, Scottish inventor Robert Stirling patented an alternative to the steam engine. His closed-cycle engine runs on pressure created by air moving back and forth between heat exchangers. An external heat source warms one exchanger, causing the air inside it to expand into the cold heat exchanger, pushing a piston. The air then cools and contracts, pulling back the piston, which pushes the air back into the warm heat exchanger, restarting the cycle.
Though Stirling's engine was more efficient and ran at lower pressure than early steam engines (which exploded occasionally), it proved impractical for industrial use and was supplanted as steam engines improved. There is now resurging interest in Stirling's invention, since it runs on any heat source, including alternative energy such as solar or geothermal. This kit is not just a technical marvel; almost a form of moving sculpture, it is satisfying to build and mesmerizing in action.
Produced by Bohm, a German firm renowned for its high-quality workmanship, this kit lets you build a reinterpretation of 19th-century Stirling engines. Made largely of solid brass, aircraft aluminum and stainless steel, the parts are precisely machined for accurate assembly, smooth operation and long working life. Assembled in about 3 hours, the kit is moderately challenging; some familiarity with mechanics or model-making is helpful. Comes with a wooden base for mounting the completed model.
The included alcohol burner (supplied empty) powers the engine at about 2500 rpm for approximately 15 minutes per fill. Measures about 6 1/4" long by 5" high, including the base.