First run of beam engine

Discussion on Stirling or "hot air" engines (all types)
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picnic
Posts: 12
Joined: Sun Nov 08, 2009 7:50 am

First run of beam engine

Post by picnic »

Here's my almost complete variation of the tin-can beam engine - couldn't resist trying it out even though it still has some temporary/missing parts. Utterly surprised and delighted that it runs although it needs a fair bit of heat!

http://www.youtube.com/watch?v=WHjKndxZtnI

It's actually the second attempt at running; the first try using a little meths burner showed signs of life but it wouldn't quite 'go'. Using a propane/butane mix blowlamp and balancing a temporary ice pack on top did the job though!

picnic
theropod2
Posts: 147
Joined: Tue Aug 16, 2011 5:05 am

Re: First run of beam engine

Post by theropod2 »

Congrats and welcome to the forum. :!:

Have you an old VCR you can tear apart? The little tape read head (bright aluminum) has a couple really sweet ball bearings. I pry the plastic covers off and wash the factory lube out with rubbing alcohol and replace it with Breakfree. If you're real careful you can use a needle to get the cover off and just press them back on with a pencil.

R
picnic
Posts: 12
Joined: Sun Nov 08, 2009 7:50 am

Re: First run of beam engine

Post by picnic »

Thanks theropod2 - good tip.

I replaced the displacer link and crank pin and fitted a water tank. I didn't have any soft solder to hand so I made the tank a good push fit on the top of the displacer cylinder and used some 'plumber's mait' quick setting epoxy (rated up to 160C) to seal the joint.

When I added water I accidentally over-filled the tank a little, so the water came over the top of the displacer cylinder - as soon as I started to run the engine the overfilling turned to good luck as it revealed a couple of pinhole leaks in the top of the (silver soldered) cylinder. I patched those up with a few blobs of the plumbers mait and it now runs pretty much non-stop for 10 to 15 mins on a small charge of meths. Happy!

Updated video: http://www.youtube.com/watch?v=QpJu1UmwVC8

picnic
theropod2
Posts: 147
Joined: Tue Aug 16, 2011 5:05 am

Re: First run of beam engine

Post by theropod2 »

Good to read. I almost guarantee that when you get some good bearings and work out all the kinks you'll have a sweet littl engine there. You might get it to run off a candle! Good work!

R


EDIT:

After watching the vid I suggest a small counterweight be added to the flywheel to offset the displacer. You might need to tune this a little for both position and heft. Just make sure it doesn't interfere with the connecting rods.
picnic
Posts: 12
Joined: Sun Nov 08, 2009 7:50 am

Re: First run of beam engine

Post by picnic »

Cheers. I was contemplating replacing the disc with a much smaller (and true-running!) metal crank disc and adding a proper flywheel to the other side to smooth out the motion which as you noted is rather jerky!
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: First run of beam engine

Post by Ian S C »

At the moment its a bit arthritic, but with a bit bigger flywheel, even if you leave the existing flywheel in place will help. Give it a run regularily, I seem to use gallons of meths, and heaps of LPG. My second motor did 2000hrs before its first overhaul, I did'nt count how many times I filled the 5 kg cylinder, it was built in 1994, overhauled in 1998, and has proberbly done a bit more than 100 hrs. Its that free thatI can take the flywheel off, and any pully as well, and it will still run, although very fast, but with no power. Ian S C
jimlarsen
Posts: 213
Joined: Sat Apr 17, 2010 11:04 am

Re: First run of beam engine

Post by jimlarsen »

I really like your engine. The brass work is nice. It looks much more refined than my pop-can approach.
http://www.youtube.com/16strings#p/u/13/pGyGOYEJR70
picnic
Posts: 12
Joined: Sun Nov 08, 2009 7:50 am

Re: First run of beam engine

Post by picnic »

Thanks Jim but it needs tweaking to run as smoothly as yours!
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: First run of beam engine

Post by Ian S C »

It wont take too much work to smooth out the running, on the new flywheel go for diameter rather than weight. Ian S C
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