My alpha Stirling engine.

Discussion on Stirling or "hot air" engines (all types)
Longboy
Posts: 106
Joined: Thu Oct 29, 2009 11:17 pm
Location: Tucson, AZ

Re: My alpha Stirling engine.

Post by Longboy »

Thanks Aviator168, Got a new perspective on these domed alpha hot pistons. Got a note from Indianola too on his engine. Check out this simular example: http://www.youtube.com/watch?v=PLDwYTGZ57I , possibly without the displacer like dome. Thanks for putting up with my banter! :mrgreen:
Longboy
Posts: 106
Joined: Thu Oct 29, 2009 11:17 pm
Location: Tucson, AZ

Re: My alpha Stirling engine.

Post by Longboy »

Ian S C wrote: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
I looked the Heylandt crown up on the web and see thats the sollution to prevent cooking the seal in the piston as it is far enough away from the heat source with this dome. Been building Gammas forever and like you have enough info for a future Alpha build! :cool:
Aviator168
Posts: 308
Joined: Tue Feb 08, 2011 2:29 pm
Location: Brokeville, NY. USA

Re: My alpha Stirling engine.

Post by Aviator168 »

Longboy wrote:Thanks Aviator168, Got a new perspective on these domed alpha hot pistons. Got a note from Indianola too on his engine. Check out this simular example: http://www.youtube.com/watch?v=PLDwYTGZ57I , possibly without the displacer like dome. Thanks for putting up with my banter! :mrgreen:
No problem. Saw some test runs of that engine. Wasn't impressive. Given the resources they have access to, they could've done much better.
Chris_74_fr
Posts: 10
Joined: Sun Feb 13, 2011 6:52 am

Re: My alpha Stirling engine.

Post by Chris_74_fr »

Aviator168 wrote: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.
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Ferraccio
Posts: 188
Joined: Thu Jan 27, 2011 10:57 am
Location: Italy

Re: My alpha Stirling engine.

Post by Ferraccio »

Chris.
If the picture represents your engine, the dislocator IS (in fact) also THE regenerator, ... in the lamination space between dislocator and cylinder.
The activity and the experiences come from Rev. Stirling before 1816 was the RIGENERATOR; was this the matter and the important innovation!
The hot air engine do NOT was invented by Rev Stirling!!!
He invented the regeneration.The regeneration is the "supporting beam" of the Stirling engine, and it do not refrigerate, conserve heat!
The wnowledge of the importance of large surface (large exchange), small mass, (easy change of temperature, and for so quick excange) of the regenerator, justify the use of very thin sheet, small metal wires, or stainless steel wool.

Personally I think is a better architecture the gamma, with parallel cylinders (not coaxial), side by side. Of course for this are necessary two shafts, one for displacer, and one for the piston.
Are reduced dead spaces, and simplified refrigeration and lubrication.

With rotating shaft in few time no true sealing is effective, to maintain the pressurization you need an external compressor.
Hopper
Posts: 53
Joined: Fri Feb 08, 2013 6:54 pm

Re: My alpha Stirling engine.

Post by Hopper »

Hi Chris, are you still on the forum these days?
I love your little engine and have been working on trying to design a copy of it since seeing it on on Youtube a few weeks ago.
Being a v-twin motorcycle enthusiast I like the elegant simplicity of your little V engine.
I would like to get a few more details of bore, stroke, connecting rod length and materials used etc if you would care to share the information.
The diagram you posted appears all pixelated on my screen, I am not sure what the problem is there?
Chris_74_fr
Posts: 10
Joined: Sun Feb 13, 2011 6:52 am

Re: My alpha Stirling engine.

Post by Chris_74_fr »

Hopper wrote:Hi Chris, are you still on the forum these days?
I love your little engine and have been working on trying to design a copy of it since seeing it on on Youtube a few weeks ago.
Being a v-twin motorcycle enthusiast I like the elegant simplicity of your little V engine.
I would like to get a few more details of bore, stroke, connecting rod length and materials used etc if you would care to share the information.
The diagram you posted appears all pixelated on my screen, I am not sure what the problem is there?
Hi Hopper,

Thank you very much. I'm happy that you like my engine.

So bore is ø 24mm and stroke 16mm. The lenght of connecting rod between axis is 28,5mm. But this dimension can be modified because it is one of the default
of my engine. Pistons are 21mm high and the axis is only at 6 mm from the down side. It should be better if the axis is at the middle of high (11.5mm). So in this case the lenght of connecting rod between axis should be 34mm. I don't know if I'm clear because I don't speak well english. So if you don't understand me, ask me again.
For materials i used, aluminium for cylinders, carter, connecting rods and pistons. Brass for liners (I don't know if it is the right word).I mean the piece in which move the piston and which is tighted in the cylinder. The crankshaft is in steel like the flywheel.

The picture I posted appears pixelated too. I don't know why.

Bye
Hopper
Posts: 53
Joined: Fri Feb 08, 2013 6:54 pm

Re: My alpha Stirling engine.

Post by Hopper »

Chris_74_fr wrote:
Hi Hopper,

Thank you very much. I'm happy that you like my engine.

So bore is ø 24mm and stroke 16mm. The lenght of connecting rod between axis is 28,5mm. But this dimension can be modified because it is one of the default
of my engine. Pistons are 21mm high and the axis is only at 6 mm from the down side. It should be better if the axis is at the middle of high (11.5mm). So in this case the lenght of connecting rod between axis should be 34mm. I don't know if I'm clear because I don't speak well english. So if you don't understand me, ask me again.
For materials i used, aluminium for cylinders, carter, connecting rods and pistons. Brass for liners (I don't know if it is the right word).I mean the piece in which move the piston and which is tighted in the cylinder. The crankshaft is in steel like the flywheel.

The picture I posted appears pixelated too. I don't know why.

Bye
Chris, thanks much for the details. Your English is fine. Certainly much better than my French, which has grown rusty since high-school French classes. I do remember though that "carter" is box so I take it to mean what we call in English the Crankcase.
Now I have the basic dimensions and your two Youtube videos to compare measurements from I think I can work out scale to build my own similar engine.
Thanks for your help. It may take me a while to get it built but I will post some pics of my version when I have made some progress.
Hopper.
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