Stirlingengineforum.com

Hi,
I've been building my own LTD stirling engine as a bit of a hobby on the weekends. After a few frustrating weeks I think I am almost there, but I'm hitting a bit of a snag. The engine is a gamma configuration.

The machine is able to push the power piston all the way up with no problems. The problem is when the piston is going back down. It gets about 3/4 of the way back down and then can't overcome the pressure in the chamber. At this point it just bounces back up the other way.

I'm pretty sure the flywheel is large enough. If I add more weight nothing really changes. I have also tried counter-balancing the flywheel, but eventually I hit a point where the piston is no longer able to push the flywheel under it's own strength.

I'm hoping someone can help. I'm sooooo close and I've put too much time and effort into this to just give up on it.

It is possible to have too much compression on an LTD Gama engine. I have found a short power piston stroke results in your engine running at lower temp differentials. As always, your engine should spin half a dozen (6) or more revolutions with the flick of the flywheel. You should be able to feel some compression but it would surprise many of you that an engine with very little felt compression actually runs well. I would try to stick with power piston diameter being the same as stroke travel. A shorter stoke is better than a longer stroke on an LTD in my expirience.