The all new mini one-lung engine
It’s been a lot of fun over the years building better and better
engines. It seems the main challenge in building these engines is
keeping the friction down. Simplicity is also a big plus, and building
the engine’s base solidly also goes a long way. And of course, the
square piston runs in a square cylinder!All of the engines I’ve built are the oscillating cylinder type.
This one I built to sell in kit form.
You can buy the plans for this online as a pdf: