New Horizontal Pop Can Stirling Engine

Discussion on Stirling or "hot air" engines (all types)
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jimlarsen
Posts: 213
Joined: Sat Apr 17, 2010 11:04 am

New Horizontal Pop Can Stirling Engine

Post by jimlarsen »

Check out the video:

http://www.youtube.com/watch?v=e6dvgEBfgJg

I see all these guys with machine shops making horizontal Stirling engines, and it makes me wonder if this can be done with pop cans. The answer is YES! Well, it runs quite a bit slower, but it works! This is part of my initial test run.
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: New Horizontal Pop Can Stirling Engine

Post by Ian S C »

Hi Jim, I imagine that the friction on the horizontal displacer shaft / gland is where the problems would be, you would need a stiffer rod than a vertical. I,m one of those blokes with a lathe etc etc. In some of my motors I use a Teflon bush in that possition, with a 3/16" dia shaft made of stainless steel tube, that will survive for many hundreds of hours of running, just don't oil it, it will swell. I don't think there are many limits on what type of motor you could make. My only tin can motor is a similar lay out to a Robinson ie vertical displacer, horizontal power cylinder. The displacer is opperated by a Scotch crank, that does introduce a bit of extra friction. Ian S C
jimlarsen
Posts: 213
Joined: Sat Apr 17, 2010 11:04 am

Re: New Horizontal Pop Can Stirling Engine

Post by jimlarsen »

Yes. The big friction points are on the displacer and the pushrod, but it is less than I thought it would be. You only have to tip the engine about 10 to 15 degrees and the displacer slides in or out. I thought about using a method as you describe, so that the displacer is suspended by the shaft and the gland. But I was afraid it would cause binding because of the weight of the displacer. I wanted to keep my technology simple, so I tried it this way.

The other challenge is getting heat on the hot end of the engine. Most of what you see over those candles is just a hood to collect the heat. It runs quite a bit stronger with a larger heat source. I am currently experimenting with different options to find the ideal balance. It will run on 1 candle, but is better with 2 or 3. I tried Sterno, but the fire was too hot. I will be trying an alcohol lamp in the near future, and maybe a small kerosene lamp.
jimlarsen
Posts: 213
Joined: Sat Apr 17, 2010 11:04 am

Re: New Horizontal Pop Can Stirling Engine

Post by jimlarsen »

I took a chance and tried running the engine on Sterno. I took a temperature reading and the hot end was over 360F. That is approaching the limits for the materials used to make it, so I didn't let it run very long this way.

Here is a video of the Sterno experiment: http://www.youtube.com/watch?v=vIBmY62sYsA
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