My alpha Stirling engine.

[Ferraccio]

Chris,
Finally a good and nice engine.

The engine has good finishes and shows good mechanical design criteria.
It would be interesting to assess energy efficiency.
I guess that the finned body between plastic tubes is the regenerator.
What have you used as a regenerator?
If you pressurize the engine note that you also pressurize the fly, otherwise the gas escapes from the seals of the shaft.
Multicylinder? Wonderful! The shaft however is more complex.
Excuse if my English is imperfect, but I'm Italian ..
Bye

[Aviator168]

power stroke occurs in the cold cylinder

Whatever.

[Longboy]

Just enlighten me. Can you tell me if this an alpha and if the hot piston delivers power?

Asked, answered, doesn't care to know.

[Ferraccio]

Ciao Chris,
Nice engine and well done!
(Un bon projet et bien fait!)
It would be interesting to see the performance.
If you do pressurized, you must also pressurize the fly, because otherwise you have losses on the shaft sealing.
This is not easy, since you should pressurize all, also an engine to start, and an electric generator.

(Pour ne pas avoir pompes qui maintiennent la pression est nécessaire un'enveloppe entièrement pressurisé, avec seulement les fils électriques passant à travers l'enveloppe sur les bornes de cloisonnement).

A multi-cylinder engine is beautiful, but a shaft for several cylinders is complex.
I see you're enthusiastic, very good, is a good way.
Excuse my English, ... but I am Italian.
Ferraccio (iron mauvaise).

[Ian S C]

There are two gamma/ concentric engines in James G. Rizzo's "The Stirling Engine Manual" that have concentric regenerators, in these motors the displacer has very little clearance in its cylinder, diverting the air flow through the regenerator matrix. Ian S C

[Aviator168]

Just enlighten me. Can you tell me if this an alpha and if the hot piston delivers power?

Asked, answered, doesn't care to know.

Say it to the builders.

[Longboy]

I sent Indianola a private note on it in YouTube and no response yet.

[Aviator168]

I sent Indianola a private note on it in YouTube and no response yet.

How about the starter of this thread who also build an alpha engine with a tube not connected to the top of the hot cylinder?

[Longboy]

I would say, "it is connected to top of cylinder". ...Don't u actually watch these videos?

[Aviator168]

I would say, "it is connected to top of cylinder". ...Don't u actually watch these videos?

You must be one of those blinds touching the elephant.

[Longboy]

Doesn't involve touch. Requires observation of the OP's video. Sorry for your shortfall, big sale on eye wear at "Vision World". Be sure to take the coupon with you. If you need help in finding the video..........I'll paint it gray and put tusks on it.

[Chris_74_fr]

Hello everybody.

Thanks everybody for your interest

I don't speak very well english but i think have understood that there is a discution to know if my engine is a gamma or an alpha. The response is simple, it is a alpha. It has got two pistons. What you call a displacer is in reality an outgrowth of the Piston. The reason why this piston is more longer that the cold piston is the high temperature of the warm cylinder. The gap between the cylinder and the piston is very little (6µ). So there is not possible to warm the cylinder just under the piston. The engine can work even if the pipe is connected at the extremity of the cylinder. But in this case it is necessary to build a intercooler to heat the air, which would create a significant dead volume due to the small size of this engine. This outgrowth (what you call wrongly a displacer) fulfills this function more efficently and in the same time, protects the warm piston of a too high temperature.

To Ferraccio : What you call a regenerator is just a pipe with cooling fins. It's a small engine. The very low quantity of gaz inside, transfers very easily his calories This kind of engine have no need of regenerator. I tried different kind of pipe of different size. There's no real difference. With the same engine at the scale 2/1 by example, a regenerator becomes necessary. But i continue to try differents configurations, with no succes at this time.
Concerning the pressurization, it is necessary to insert a seal on the shaft. I will use a quadring. The best conception is effectively a full closed engine with a generator inside with only static seals. But i'm not arrive here yet.

Thanks for your interst about the four cylinder. But you have to be patient. I make that during my loose time. And i don't have it a lot at this time.

Bye

[Longboy]

Thanks Chris 74. Your computor draft of your engine will help those debating weather your engine is Gamma or Alpha type. For what looks like a displacer can now be seen as being sealed at the connecting rod end to the cylinder wall and the air tube is above the sealed part of hot piston at top dead center. Those who look at engines identified as Alphas on Youtube should also note where the air transfer passage is in relation to the pistons at top dead center and builders descriptions and videos sometimes don't provide enough clarity to make the determination and provide for debating the engine type.

[Ian S C]

It's an Alpha type, with a Heylandt crown on the hot piston, looks good.
I'v got to upgrade, can't see Utube with the server I'v got. From the diagram I'v got enough to build one myself. Ian S C

[Aviator168]

All alpha engines I saw on the net is of this type except one (http://www.youtube.com/watch?v=T8S7bA1I0fQ) which is a true text book alpha. They even have a name for it. "Alpha Rider".

The gap between the cylinder and the piston is very little (6µ). So there is not possible to warm the cylinder just under the piston.

Chris,
I take it that 6µ is 6 x 1/1000000 meter. If that is the case, the gap is too small. The reason this configuration works much better than text book alpha is that the gas can be easily heated up and be brought to a higher temp when it is forced to go through that gap. You should look at Deven's engine specs. The gap between the hot cylinder and the piston is 0.025" to a side on his engine, and the air seal gap is 0.0004" to a side. My design have that gap extended all the way to the top of the cylinder. However, it might be difficult to make if the engine is small.