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Do you have an Essex engine, VincentG? I thought I could see one in the background of one of your recent videos.

... I couldn't find a P19 "ultra LTD" on the net. Do you have any old brochures with information about them? ... It was really just one prototype engine, I think. But had a counter balance similar to yours. Some information and links in this post: https://stirlingengineforum.com/viewtopic...

Thanks Tom, I'll back off and have a think about this. Apologies for crashing in on this interesting thread! No need to "back off", the forum is for discussion and debate. BTW I don't necessarily think a cold side is necessarily "bad". It can often be helpful and increase power....

... I lean towards basic Otto (even Tom has migrated here, but appears he can't handle Otto ECE buzz). ... Most, pretty much all references I've seen define Otto cycle as "an internal combustion" engine cycle, so an external combustion. Otto cycle seems like a contradiction in terms. Otto...

I had a long winded and detailed post typed out but it was lost, so I'll cut to the chase. The 1903 Essex type 1 offers better performance than the seemingly impressive Ford/Philips 4-215. The Essex is driven off the hot end, a system that is so effective, it's displacer actually lags the power pis...

Many thanks Vincent. I'm just glueing up a temporary displacer with two crossed plys of corrugated cardboard and a facing of beer can aluminium while I gather materials for something more permanent. I do want to run this on my stovetop, so I'll manufacture an aluminium sidewall with high temperatur...

BTW, what are these protrusions that look like stacks of coins:

There are various materials you could make a high temperature displacer out of. Since the displacer is already counterbalanced, weight is not really an issue. Large sheets of pressed mica bonded with silicone are available as "cut to fit" wave guide cover replacement for microwave ovens, o...

..... So I'm not sure how long a 'dwell' of no heat input Tom thinks would improve the dynamics. Imagine someone being pushed on a swing. The "dwell" would be the entire time the swing is not being pushed. Ideally the heat input should be variable so that it could be extended when additio...

... But heating of the working fluid needs to recommence as soon as the displacer starts to shift it back from the cold end, which happens before the piston reaches BDC. So I'm not sure how long a 'dwell' of no heat input Tom thinks would improve the dynamics. You are,... sort of right, if by "...

....the big problem with those points is that Tom doesn't believe in 'constant T volume change', neither expansion nor compression. He believes in adiabatic. And he thinks adding an electric generator will change that process. Granted, real processes are somewhere between adiabatic and constant T, ...

There are additional factors not indicated or apparent looking at a typical PV diagram. Real engines have actual physical mass, which has inertia and momentum. Reciprocating engines have pistons which have weight, velocity and momentum. pv_velocity_momentum.jpg From TDC (far left) to midway towards ...

.... At this point I respectfully request that, would Tom please give us an image of a PV diagram with his proposed cycle drawn. Tom is very good at providing images and graphs. .... This is a real time tracing of an LTD Stirling: stirling_pv_real.jpg https://youtu.be/ck8thAoi_rA?si=Khb77JAOWyneplv...

Tom, If you could build an engine that had ice at the cold end, but that ice never, ever melted, what role would it have within the engine? My intuition says that if no heat/energy transfers into the ice, then it isn't having any effect on the engine cycle. It's not too difficult to conceptualize i...

Carnot efficiency theory, or whatever you want to call it dictates that the 75 joules go into the "cold reservoir" period. No option for using it for "back work". It is rejected as heat, because supposedly it is "impossible" for it to be converted to work positive, neg...