MM20 - The ASAP engine

Technical details
Year of construction 2001
Power piston stroke 24 mm
  diameter 40 mm
Displacer piston stroke 24 mm
  diameter 64 mm
Flywheel  diameter 120 mm
  material plywood
Idle speed 30 rpm
Energy source alcohol


ASAP - "as simple as possible" is easy to appreciate when looking at the finished model engine. Thereby, the idea of Daniel Lyonnett's proved to be a good pattern for the 2001 project week at our school. But unfortunately, building this ASAP model turned out to be easy at all. The holder is easily and quickly made of plywood as shown on the delineation. More problematic are the pushrods for both pistons. As it is the case with all the other stirling engines, extent of their sealing and a minimum of friction are the deciding factors for success or failure. Concerning our model, success meant, as often, the result of a number of overcome flops. Meanwhile, the engine runs, after a fashion. 
The next engine will surely be built without using plywood parts: ASAP - as soon as possible ;-)