Hi mhafele !
1 / hot cap should be as thin as possible ( thickness of hot cap my stirling :about = 0.5 mm )
2 / between hot and cold zone should be insulation ( insulation :you can use teflon...)
High mhafele
Damn nice engine you built - It appears you do have insulation between the hot and cold side of the engine.
I think that the cooling area (assuming it is aluminium) is a little small. With that much heat the cooling fins can't get rid of the heat. You could try using a small fan next to cooling side or make a water jacket instead of fins.
I do love the way you have made the engine with the generator - Well Done
Regards Trev
With a generator on the motor, it I possible to use a small electric fan from a computer, but these are generally 12V. one of my motors has one fitted to it's radiator.
Ian S C
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So here is my ALPHA motor, similar power out put to the Beta above, but about twenty years newer. The steel cylinder head has been replaced with an aluminium one, and the water jackets are gone(they never were used, it would go all day without over heating), these are replaced with aluminium fins.
Ian S C
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With a ring burner with the motor vertical with the hot end up, the heat rises, easier to keep the cold end cool.
This is my free piston motor, it's a bit rough, it's been modified a number of times. Burner at the top.
Ian S C
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I wouldn't exactly say beautiful, it usually works, but not really fast enough, the maximum speed is about 1000 hz, and I would like 3000 hz, it does generate a little power, enough to run the radio, but the low frequency AC current takes a fair bit of smoothing to get a DC current without too much AC noise on the radio.
Ian S C
Did some tweaking and reached 6500 rpm. Until the hot cap blew off. Was held in with high temp lock tight but I was using propane torch. Guessing it got to hot.
That's excellent speed, just needs a bit of engineering to redesign the hot end. If you haven't broken something, you are not really trying hard enough, the hot end probably needs to be brazed into the flange, what is the hot cap made of?
Ian S C