Stirlingengineforum.com

The "Cloud in a bottle" demo - it's not really an experiment - is largely a demonstration of the rather surprising properties of humidity and vapour saturation, not of temperature directly. The cloud forms because the loss of pressure moves the dew-point. (I've seen it done much more impre...

Tom,
The problem with treating ambient as being equivalent to zero, is 'pressure' doesn't agree with that at all - gas pressure at 300K is 75% of that at 400K (for the same volume) ...

What's the comment on the left, about "cold steam" all about?

Firstly - proving that Carnot is wrong is actually easier than proving it is correct - essentially Tom is claiming that Reindeer CAN fly, which is easy to prove (if true) - just need to see one flying, and/or show appropriate Maths. Secondly though, you I need to support part of (what I understand) ...

For the two-stroke engines, would it be possible to invert them, and effectively have a sump above the pistons?

What that diagram doesn't make clear, is what the two parts of the engine are meant to do? If they are intended to be linked to a common shaft, then I would suggest that that is a very bad idea - allegedly simply linking two IC engines to the same shaft is a very big deal, so getting the power outpu...

If I may expand slightly on an earlier comment or two - a "Stirling Heat Pump" is a fairly well-known device, though rarely needed/built by amateurs, I suspect! As noted, it needs something to drive it, which can just as easily be a "Stirling Engine" as anything else.

May I suggest cutting a larger disc for the base, then those supports can still be used, but twisted at an angle to match?

If valves and such are involved, you need to be looking at some of the relatives to the Stirlings, such as the Manson Engine

Close, but not quite - the retro-reflective materials that they use on road signs etc rely on hemi-spheres, not full-spheres - like having a million tiny parabolic satellite dishes. Even then, only about 50% of them point in the right direction, and since they aren't parabolic, those that do reflect...

Far from being a curiosity, in my solar engine, the water vapor condenses in the power cylinder and will slow it down and then stop it. Have you tried using silica gel (or other dessicant) to dry your air? It doesn't need to be pressurised to do this, you just need a decent seal to ensure that the ...

If it helps, bear in mind that some commercial Stirlings use Hydrogen or Helium as the working gas, so no mixture or water vapour effects. As far as I know, these are more efficient, but don't work substantially differently from air-based engines.

Tom, I see you mention "molecular attraction" again - I'm not aware that any common gas has this property; indeed I was under the impression that a truly un-constrained gas would expand to fill whatever container it is in, regardless of temperature and pressure. Maybe I'm misunderstanding ...

"Why do these various engines have heavy weights on the diaphragm "pistons"?" I suspect the main reason is that the engine is at atmospheric pressure inside, at rest. Once the engine has been 'fired up' the internal pressure will rise substantially. For a diaphragm-based engine i...

I quite agree with Tom: the mass of a piston is directly _ counter _ to the ideal operation of _ any _ engine - a massless piston is always going to be better overall than a heavy one.