Heres some photo's of a moving cylinder engine I built, based on Hubert Stierhofs MC Easy.
I had a small stepper motor connected to it which it just about ran making enough power
to power a LED (dimly!) It's made from plywood and aluminium with a balloon for the diaphragm
I actually found it has a small leak so it'll probably run a bit better once that is sealed.
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The displacer is weighted at the thin end and has a wire wool regenerator but I forgot to photograph this!
Interesting design! I only just discovered this type of Stirling :)
I wonder if it would work better if the pivot point was right at the bottom of the air box rather than a little bit up from the bottom? Or did you find that having it like that makes it run better?
I actually experimented with the pivot point and found it works best about a quarter of the way up from the bottom, the diaphragm didn't move enough to tip the displacer with the pivot right at the bottom but there's no reason why you couldn't have the pivot right at the bottom with the diaphragm low, like this very nice model : http://www.youtube.com/watch?v=WTQZ80eNyec
I can't get it to run it's little generator though seems to have lost some power, not sure why
Mmm I see :) the pivot point can be adjusted much more easily than the piston location. Having read some of MIT's "thermodynamics and propulsion course" online, I can imagine how hard I would probably turn out to be to calculate all this stuff in advance of actually building it :D
My first engine is still just a pile of metal parts right now, but starting to come together. I quickly decided the fastest way to a functional engine was to just build one that roughly followed the proportions of existing engines. Maybe one day I will have the time to try my hand at simulating it in some crude way.
