Tin can engine. How to calculate crankshaft?

[danteal]

Hello everybody, I'd like to build a "tin can engine " but I can't understand how to calculate, measurement, the crankshaft.
Is there a rule? Is there a proportion?

[fullofhotair]

Thats all Ive made. So I can give you a little advice,First dont try to design your first engine. There are way to many free plans out there that work great.The diaphragm power piston is the easiest model.The crankshaft is by far the hardest part.Follow the instructions to the letter,Straight flat shaft and 90 degree angles are most impotant.Use a little heavier steel wire instead of some soft copper wire just because its easier to bend.the power piston is offset from the displacer by 90 degrees, I think the ratio is 1.5 to 1 on displacer stroke to power piston,but all thats on utube .If your first engine works ok youll be hooked.

[danteal]

Ok, I'm seriusly disconsolate. I tried all day with no results. Somebody can send me a very simple plan to build? I tried the scraptopower plan without result.
Thanks

[fullofhotair]

This is a series of 19 utube videos on how to build a simple tin can stirling engine.It takes you from the very beginning, to lighting her up and watching her run. http://youtu.be/-szN_IbSt70