One reason I built this one was to prove to myself that I really understood how they worked. For that reason, I designed this all myself. Not that there's SO MUCH there. Also, there are tons of videos on YouTube that are identical to mine.
It's be really awesome to scale this up. Like with an oil drum for the displacer cylinder. I'd start that right away, except not only do I not have an oil drum, I'd need access to machine tools to make the power cylinder.
- With the power piston shaft and displacer piston shaft mounted on the same point, getting distances right is a little tricky. It's a big parallelogram this way. Make them separate next time. Maybe even on a rotating collar so the phase angle between can be modified.
- If the shaft tiepoints have a lot of play in them, the engine works jerkily if at all (because all the motion is taken up in using the play).
- I think I overdid it on the height and underdid it on the width. Could have used a little angle-reducing distance on the piston shaft. Alternatively, shorten the stroke.
- The flywheel is a little heavy. The momentum should carry it through the compression stroke, it shouldn't have to be barely sucked in.