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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...

The displacer phase angle is not subject to my opinion.

Tom I'd recommend you spin one of your engines by hand and take note of when the displacer fully exposes the hot plate.

I should also point out that displacer movement is "modified" from normal by the extreme rod to stroke ratio combined with displacer stroke > power piston stroke. The original patent description has the engine spinning the other way. So I think it was designed with standard phasing in mind...

Hopefully this video definitively shows that the displacer timing is 180 degrees behind the standard.

The crank assembly is pressed together and hasn't been modified. It is the same as all Essex engines that can be viewed on YouTube.

https://youtu.be/F3dqnWTgpWc?si=oWAuizocmAkX40yV

Typically the displacer would fully expose the hot end before the power piston reaches TDC.

In this case the power piston reached TDC before the hot end is fully exposed.

I second guessed myself for a while when I first saw this feature because everything is backwards from a normal Beta.

There is a much simpler reason for three temperatures.

We exist in the third temperature. If there was hot and cold on tap, we would have no need for heat pumps and much less need for electricity in the first place.