need help making my first stirling engine

Discussion on Stirling or "hot air" engines (all types)
alecb
Posts: 11
Joined: Sat Oct 29, 2011 5:42 pm

need help making my first stirling engine

Postby alecb » Sat Oct 29, 2011 5:47 pm

i tried to make a beta engine with the diaphram about an hour ago and it wouldent work. then being a dipshit i tried to jumstart it with a dremel tool and it flew apart. can you guys tell me how to make an alpha stirling engine? i had an idea of using jb weld as a piston.

Ian S C
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Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: need help making my first stirling engine

Postby Ian S C » Sun Oct 30, 2011 2:04 am

A BETA motor has the power piston, and the displacer in the one cylinder, to fit a diaphram you proberbly have a GAMMA type with two separate cylinders, one for the displacer, and the other with the power piston/diaphram. I don't know how you build your motors, mine are built with the use of a lathe, and mill, and some have the hot end of the displacer, and its cylinder TIG welded stainless steel. As far as an ALPHA motor goes I don't think it would be possible without a lathe, you could not make it with tin cans. theres a pic of one in my photo album with a little power hacksaw on it, and a pic of it on the bench awaiting its first run. Look up ANDY ROSS and hot air engines, I think that might help explain the ALPHA motor. Ian S C PS if you must turn the motor over under power, try something slower than a Dremmel.

alecb
Posts: 11
Joined: Sat Oct 29, 2011 5:42 pm

Re: need help making my first stirling engine

Postby alecb » Sun Oct 30, 2011 10:19 pm

yeah if i made an alpha stirling i would use brass tubes and fittings with pistons made of jb weld. do you think that would work? also i would like to make it horozontal instead of a v twin type so would the cranks have to be at a 90 degree angle to eachother?

Ian S C
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Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: need help making my first stirling engine

Postby Ian S C » Mon Oct 31, 2011 4:43 am

The JB weld seems to work OK on the tin can motors, but they run on a medium heat, my motors run on high temperature, ie., the hot end glowing red (dull for mild steel, bright for stainless), and even with good cooling, things can get a bit hot. Thats why I use cast iron for pistons, short of using graphite, cast iron is about the best as far as friction goes.
If you make your ALPHA motor a V type, you will only need one crankpin, if you make it parallelyou need either two cranks on the crankshaft, or one cylinder with a bell crank, and a single crank on the shaft. The way I sorted it was to use a Ross Yoke.
You can make it horizontal, vertical, or any where between. With a vertical displacer its easier to get it to stay centered than a horizontal one. I'v got some with the hot end at the top, and others at the bottom. I'v also got one with the crankshaft vertical, and the displacer, and power cylinder horizontal.
Start with a simple motor to a known design, get it going well, then get stuck in, I'm building my 17th motor, its a beam one similar to one sold by Grizzly, its got a power cylinder of 3/8" bore, and 1/2" stroke. Ian S C

alecb
Posts: 11
Joined: Sat Oct 29, 2011 5:42 pm

Re: need help making my first stirling engine

Postby alecb » Tue Nov 01, 2011 9:15 pm

could i possibly make an alpha engine using 1 inch or half inch brass tubing and jb weld pistons? if so how long do you think the pistons should be? im thinking an inch or 1/2 an inch tubing. also any ideas for connecting rods? i was thinking of using small eye bolts(in the pic below) as a way to attach a connecting rod to the engine.
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Ian S C
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Location: New Zealand

Re: need help making my first stirling engine

Postby Ian S C » Wed Nov 02, 2011 5:40 pm

What are you planning on using for a hot cap on the hot piston, this is a bit similar in construction to a displacer, it must be light weight, and air tight. A hight of 1 1/2 to2 times the piston diameter would be OK . I wonder if you could put say 2 grooves in the JB weld piston, and put Teflon plumbers tape as if it was piston rings. Ian S C

alecb
Posts: 11
Joined: Sat Oct 29, 2011 5:42 pm

Re: need help making my first stirling engine

Postby alecb » Wed Nov 02, 2011 10:32 pm

i am not shure what you mean. i am making an engine like this http://www.animatedengines.com/vstirling.shtml . i want to cut out a L shaped piece of 1 inch plywood to secure the bores to so i can build the crank and make the pistons and connect all the moving parts together and having the plwood as a base allows me to scoot the bores up and down (closer or farther) away from the crank to fine tune the space between the top of the piston and the head. and to cap off the cylinder ill just use a large fitting with a tit on it or make one with an end cap. (see pic below) this was just a quick sketch
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this was just a quick sketch
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alecb
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Re: need help making my first stirling engine

Postby alecb » Wed Nov 02, 2011 10:33 pm

also about the piston rings, thats a great idea. ill look into it. maby i could use rubber o rings if i can find the right size

Ian S C
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Location: New Zealand

Re: need help making my first stirling engine

Postby Ian S C » Thu Nov 03, 2011 6:08 pm

I won't go into the design you have for your engine at the moment, I'm using the computor at our local library as mine is away for repair.
as far as the pistons go, the Teflon tape from the hardware storewill only cost a few cents/ pence, and it has the advantage of having about the lowest coefficient of friction you can get, I just twist it into a string then wrap it around in the groove in the piston. Your motor will need to run fairly hot at the hot end, so I don't think JB weld would last very long for the hot piston without some form of protection.
When, and if my computor comes back I'll try and put some sketchs of the construction of an ALPHA motor. Ian S C

alecb
Posts: 11
Joined: Sat Oct 29, 2011 5:42 pm

Re: need help making my first stirling engine

Postby alecb » Thu Nov 03, 2011 7:46 pm

Thanks ian, i will be waiting for the sketches. my email is alec64b@yahoo.com if you want to email them.

Ian S C
Posts: 1448
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: need help making my first stirling engine

Postby Ian S C » Fri Nov 04, 2011 2:25 pm

My new computor is coming middle of next week, we'll see what happens then! The computor I'm using for most stuff at the moment, at home is on Windows 95, and won't do this web-site for some reason. Ian S C

alecb
Posts: 11
Joined: Sat Oct 29, 2011 5:42 pm

Re: need help making my first stirling engine

Postby alecb » Sat Nov 05, 2011 12:04 pm

i gave the engine a try again and pulled out my dremel tool and got some correct glue and i followed these instructions exactly and it still wont work :mad: http://www.midnightkite.com/index.aspx?URL=Stirling
btw i used jb weld puddy for this engine. its one of the best glues i have ever used. you should give it a try. it hardens in 3-5 minuts and is cured within an hour or so i guess.

martinnman
Posts: 6
Joined: Thu Oct 13, 2011 4:22 am

Re: need help making my first stirling engine

Postby martinnman » Tue Nov 08, 2011 10:03 pm

Well, here are some tips. Hope these may help you.

- Search the basics of how the Stirling engine works.
- Find why hydrogen is not the target gas for use in closed circuit due to the way it is difficult to keep hydrogen from leaking, and the air regularly works well as a working language of compression / expansion of gases.
- Cylinder is not tight, but allows gas to flow around it.
- Cylinder should go almost to the bitter end of the chamber of the cycle, both in and out.
- No gasket, to reduce friction, which would kill performance.

Bidwell
Posts: 10
Joined: Sun Jan 15, 2012 10:31 am
Location: Burbank CA

Re: need help making my first stirling engine

Postby Bidwell » Sun Jan 15, 2012 11:54 am

I used Bondo (body putty) into a piece of copper pipe. Works real slick............so far.

Ian S C
Posts: 1448
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: need help making my first stirling engine

Postby Ian S C » Mon Jan 16, 2012 3:20 am

If you use the slow curing JB Weld, it will alow you about 100*C more, quick cure 400*C, slow cure 500*C.
Ian S C


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