A fake Wankel engine

[mklotz]

I call this engine WANKELIKE because it looks something like a Wankel but really isn't. The familiar Reuleaux triangle-shaped rotor of the Wankel has been replaced with a simple cylinder and the epitrochoid-shaped chamber has been replaced with a cartouche-like opening.

This makes it easier to machine but introduces a weird geometric constraint. The "cylinder" has to move up and down when the engine is running! What can I say; it's a silly design, totally impractical but makes for excellent eye-candy at model engineering shows.

At the beginning of the video I turn it over slowly by hand so you can see the piston inside the chamber. Plexiglass chamber walls make it visible but guarantee the engine will never be run on steam. Note that the piston is offset on the crankshaft and it's this motion that forces the chamber to move up and down as the crankshaft rotates.

All the valving, intake and exhaust, is done via a central channel in the crankshaft that admits air to channels in the piston that communicate with the vacancies in the chamber. The engine is completely symmetrical so it can be reversed by simply interchanging the intake and exhaust.

Building the engine takes some care. The two biggest items are getting the chamber moving smoothly on the uprights and sealing the chamber.