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new engine advices before is too late :)

Posted: Tue Apr 16, 2013 8:52 am
by Ante
My new engine,
please comment


http://img541.imageshack.us/img541/166/motor13.jpg

Is it aluminum cooler to long?
is it displacer bushing short?
dimension ratios ok ? (it is not exact I am using available parts)
cylinder and piston are shock absorber, displacer is made of stainless steel pipe (upper cup is aluminum) , displacer cylinder also lower part SSpipe upper part turned aluminum chuck and crankshaft is welded carbon steel.
engine should work on open wood fire

piston rod bearings are needle bearings and axial movement is limited by small brass pipes, is that problem for friction?

any other proposal just shoot

Salute!
Ante

Re: new engine advices before is too late :)

Posted: Tue Apr 16, 2013 11:34 am
by ruizfa
i think looks good.. its a gamma type.. right? where is the conection beetwen the hot cilinder and the cold piston?

Re: new engine advices before is too late :)

Posted: Wed Apr 17, 2013 3:41 am
by Ian S C
I'll have to wait until tomorrow to get on broadband to see your picture. I hope you have the stainless steel parts of the displacer at the hot end, and the aluminium at the cold end. Shocky inner tube good cylinder, but the piston with its ring, proberbly too tight, and without, too loose, I'd make another lighter one without all the holes in the crown. Ian S C

Re: new engine advices before is too late :)

Posted: Wed Apr 17, 2013 5:40 am
by Ante
here is image on forum gallery with smaller resolution

[album]114[/album]

I draw this drawing from parts so i forget to "put" connecting hole.

Piston is not too lose without piston ring. It can not drop under its own weight when I close cylinder, but I have cast iron if i change my mind.
SS on hot end of course.

Salute

Re: new engine advices before is too late :)

Posted: Wed Apr 17, 2013 9:17 pm
by Hopper
It looks basically good. The cooling fins on the 'cold end" may be a little too long. Most of the commercial stirlings produced in the old days had the cold end comprising about one third of the total length of the displacer cylinder. That was using brass or steel for the cylinder. Most modern designs split it about 50/50 between hot and cold ends. (I have just researched this for a design of my own) but using stainless steel or glass tube for the cylinder.

The other thing might be the power piston is a bit short and might tend to kick over at an angle and cause friction.

At the below link you will find the drawings for a very similar engine, james Senft's "Moriya" engine. You could scale off his drawings to compare with yours.

The link:
http://courses.washington.edu/me355b/Fa ... iption.pdf

Re: new engine advices before is too late :)

Posted: Sat Apr 20, 2013 4:45 am
by Ian S C
You ask about friction, if you can remove the hot cap, or other wise open the motor, and flick the flywheel over, it should rotate freely for quite a number of revs. The crankshaft uncoupled from the con rods should proberbly turn for a miniute, give or take a bit.
Make sure the displacer is air tight, you can do this by placeing it in hot water, if there is a leak bubbles will appear as the air inside expands. Ian S C

Re: new engine advices before is too late :)

Posted: Fri May 17, 2013 4:54 am
by Ante

Re: new engine advices before is too late :)

Posted: Mon Jun 03, 2013 12:37 pm
by Ante
If someone is interested..

I am putting 3D model of engine in pdf (you can turn and zoom engine)
but must be downloaded:
https://www.dropbox.com/s/wwmvszd56nm59 ... 202013.PDF

and here few pictures of engine in progress:

https://www.dropbox.com/s/xnfcq3cdf8gxt ... 161939.jpg
https://www.dropbox.com/s/h9fxees80lzcr ... 162015.jpg
https://www.dropbox.com/s/a1ak9xijeww0i ... 162036.jpg

Anybody knows dimension of "overlap" in microns to make crankshaft with press fit, pins have diameters 7 and 5 mm.

Any comments are welcomed

Salute Ante

Re: new engine advices before is too late :)

Posted: Fri Jul 05, 2013 11:49 am
by Ante
here it is:

I think, it can be better speed without load about 450 max 700



Salute