why doesn my stirling engine work?
Because the throw of the con-rod crank is too big, this causes the flywheel to try and drive the diaphragm. I found it works quite well with a crank throw as little as 2mm, however because it’s so difficult to make it so small you can achieve the same thing by simply making the flywheel-end crankshaft bearing an open V shape, the crankshaft just rests in it & lifts out of it briefly on each rotation, but I don’t think this takes any energy out of the system. Anyway it stops the crank jamming against the diaphragm. Because this reduces the bearing forces to nothing at all it means you can make the whole top end out of a piece of folded card; it’s much easier to fit the crankshaft because it just rests in two ‘V’ notches, you can constrain one end with a paperclip sellotaped to the card. A polythene diaphragm is now just as efficient as one made from a balloon because the floating crankshaft bearing does what the elasticity of the balloon was doing. So you don’t need to use superglue. If
