Stirling essex - beta or gamma ?

Discussion on Stirling or "hot air" engines (all types)
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staska
Posts: 88
Joined: Thu Sep 05, 2013 10:10 am

Stirling essex - beta or gamma ?

Post by staska »

Hi.

Does essex engine configuration belongs to beta or gamma type of stirling engine ?

Image

For me it looks like more beta, because it is possible to reduce dead volume on compression stroke - power piston can follow into displacer area like in beta type ?
Ian S C
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Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Stirling essex - beta or gamma ?

Post by Ian S C »

Staska, it resembles a BETA type, just that the hot end is at the other end from normal, different, not too sure about the cooling which is just as important as the heating. Was a motor built and run from this design?
Ian S C
staska
Posts: 88
Joined: Thu Sep 05, 2013 10:10 am

Re: Stirling essex - beta or gamma ?

Post by staska »

Yes, it does run. And there are kits in normal price: http://myfordboy.blogspot.com/p/the-ess ... ngine.html By original it was adverted as 1/40th hp engine. Or 1/10hp if double cylinder ?

http://books.google.com.au/books?id=iOA ... es&f=false

It had a lot of interesting videos on page too. I had contacted with author, it does not disclose any dimensions for calculating any raw data. It looks like be 4x3 cm bore and stroke for displacer, taken from this photo: http://2.bp.blogspot.com/-5ydrHlD-Q9U/U ... cs+010.jpg and to know that Flywheel diameter is 6"

For me it is perfect kinematic to be made from any two cylinder engine with 180 bended crank shaft and pushrods, and to allow small pressure without sealed crankcase.
staska
Posts: 88
Joined: Thu Sep 05, 2013 10:10 am

Re: Stirling essex - beta or gamma ?

Post by staska »

Does any-one have any ideas ? Does essex stirling engine is the answer to question about typical 1/1.5 ratio of power piston to displacer found in normal gamma engines with cold expansion space ?
staska
Posts: 88
Joined: Thu Sep 05, 2013 10:10 am

Re: Stirling essex - beta or gamma ?

Post by staska »

Interesting info :http://arc.aiaa.org/doi/abs/10.2514/6.1994-3952 or http://papers.sae.org/929026/

Quote:

It was demonstrated by analytical means, that the specific work obtainable from a Stirling type engine, with separate power and displacer cylinders, having the power cylinder connected to the hot zone of the displacer cylinder is, for typical operating conditions, about twice that obtainable when the power cylinder is connected to the cold zone.
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Stirling essex - beta or gamma ?

Post by Ian S C »

Ahh yes, but has it been proved practice, analytics is one thing, but hard metal is (sometimes) another.
Ian S C
staska
Posts: 88
Joined: Thu Sep 05, 2013 10:10 am

Re: Stirling essex - beta or gamma ?

Post by staska »

Yes.

http://www3.nd.edu/~me463d18/Files/Dere ... esting.pdf

With essex, it should be even better - we could negate any dead space with common swept volume. But - gamma gives posibility to make thin-tube heat exchanger for hot end without additional piston ring...

"academics" http://papers.sae.org/929026/, http://arc.aiaa.org/doi/abs/10.2514/6.1994-3867 , http://arc.aiaa.org/doi/abs/10.2514/6.1994-3952 (i even bought last one) says up to 1.6-1.7 more power from.

But - it is possible what in real engine with have 100 watt minus 30w = 70 watt for friction, for heat side vork extraction we have 170 watt - 30 watt - 140w
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