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Moving this discussion from the Essex thread, I do see the potential of a regenerator. Let's say the regenerator is contained in a separate circuit outside the engine. Then if the regenerator is active(gas flowing through) only when the displacer is moving, and is isolated from the rest of the syste...

Imo the Essex works so good with such a simple design because it makes no attempt at traditional "regeneration" and instead makes an attempt at minimizing thermal mass. I would wager that any attempt at adding on a traditional regenerator would lower specific power output. Again, imo, in p...

Due to the thin brass walls(.015") of the main tube, displacer and power piston, the original Essex has pretty effective regeneration without any additional dead space or flow restriction. I'll try to film a thermal video to show this later.

Not sure if you will find this relevant. https://youtube.com/shorts/AvZ_GvFu8xE?si=Zyp537_zeX7PRnk7 I don't think chasing surface area with complicated design is needed until some other things are figured out. Imo the overall proximity of the heat exchanger to the gas is more important, and most imp...

I think it would be helpful to put pressure and volume values on these ideal PV graphs.

Yes, I actually measured my aluminum plate, painted black over boiling water and saw 250 degrees f. They are good for comparison but definitely dont seem accurate in all circumstances.

Hey Tom have all your below ambient results been with an acrylic hot plate? I just realized that and it explains why my engine with metal plate always heat soaks the cold plate.

I know the metal hot plate is way overkill for these small ltd engines and have been meaning to test a plastic hot end.

No the point I was making is that the claims of inaccuracies due to the different emissivity of various materials is perhaps negligible. (I and others have made these claims.)


I'm just suggesting that these models are just too small to sway anyone's belief.

Is this right or have I fouled up? 9072 Watts in to get 145 Watts shaft power out seems very poor. Surely they'd have been better off slapping electric underfloor heating elements all over the base of the displacer cylinder than running heated Ethylene glycol round a small area of the sidewalls? Ag...

Tom, in the name of science I spray painted half of a Pyrex bowl flat black and tested with the thermal gun at room temperature and after hot water exposure. There was no discernable difference except for a small variation where the paint transitioned to clear glass. I also tested a piece of black p...

Regardless of power output that is a really nice engine that will look great on the shelf for now haha.

Tom I actually think possible the self cooling aspect of these engines you are exploring. But these ir guns are finicky, even my expensive one. If you paint everything flat black, then we can start talking. It still will not be a very accurate overall reading, but at least the general comparison of ...

Yup ill reshoot video with more accurate explanation of kinematics. Double reversal is a good description here. It still hurts my pea brain thinking about whats going on exactly. Btw the original Essex has 1.5" displacer stroke compared to 2" for the myfordboy version. Between that and the...

You guys are right. I must be drinking too much lately. When operating the Essex by hand, the extreme rod to stroke ratio of the displacer causes a very sudden movement of the displacer relative to the power piston that I was mistaking for a difference in phasing. That combined with the rod kinda so...