The Ringbom stirling cycle engine is unique in that there is no mechanical connection to the displacer. The displacer operates itself from the pulsating pressure variations within the engine. The engine has only four moving parts.

The engine makes a distinctive thumping sound like no other engine and runs at a fairly constant speed of around 700 RPM when powered by my Mini Propane burner which is highly recommended (see the "Other Interesting Projects" menu).

This is a water cooled model and the plans also include an engine driven oscillating water pump that has only three moving parts and no check valves! It is your choice to build the pump or to supply cooling water to the engine by other means.

Ringbom engines and the plans are very rare but now you can build a Ringbom engine of your own!

The plans set consists of 11 sheets of drawings and 2 sheets of construction and assembly notes.

Specifications: Flywheel Diameter: 3-1/2", Cylinder Bore: 1/2", Piston Stroke: 5/8", Overall Height: 6-1/4"  Experience Level: 5