This 2-cylinder reversible Stirling cycle engine was built by Alphonse C. Vassallo, of California, in 1971. (Courtesy of Cherise Vassallo, Ingrid Vassallo, Andre Vassallo). A Stirling engine is a device that converts heat energy into mechanical power by alternating compressing and expanding a fixed quantity of air (or other gas) at different temperatures. Intrigued by the concept, Mr. Vassallo designed and built this horizontal twin inline Stirling engine. It sports custom made burners at the top of the cylinders and his custom-designed reversing mechanism to control the direction of the output shaft.
Shortly after completion, Al tested the engine in a model boat a Spreckles Lake in golden Gate Park, San Francisco, CA. The success of this engine led him to design and develop several other Stirling cycle engines. The engine is 21″-long, 8″-wide, 7″-high, and 12 lbs.