Troubleshooting my tin can Stirling

[dwzavaleta]

Hi folks - this is my first post here; I'm asking for your help in troubleshooting my version of Darryl's tin can Stirling design.

Overview of DZ's Stirling.jpg (221.92 KiB) Viewed 7762 times

power cylinder.jpg (207.97 KiB) Viewed 7762 times

displacer rod.jpg (185.34 KiB) Viewed 7762 times

With the power piston detached, the flywheel-beam-displacer group will make 3-4 cycles. The power piston is of 3/4" type L copper pipe filled with J-B Weld and fitted into the cylinder of repair pipe. This piston-cylinder fit is pretty good, but when heating the complete assembly on the stove, tho, it seems there's no pressure on the piston. I'm wondering whether some water is leaking around nut on the displacer rod nipple- maybe I didn't seat the Beer Nuts can low enough onto the upper end of the main cylinder - but would a little water make any difference, anyway?

Any suggestions?

Thanks also, Darryl, for putting your design up for open use.

[speedless]

Hi
http://stirlingengineforum.com/viewtopic.php?f=1&t=344
Jan

[dwzavaleta]

Many thanks for your input. I'm a woodworking science teacher whose goal here is to help high school students build this in class as part of a solar energy project, so I'm looking for a design that is doable without a machine shop or soldering iron, and using materials readily available at local hardware stores for under $25 or so. Doesn't have to have a lot of power, but a final goal is generate enough power to light an LED or something.

Are there other designs I should be considering instead? I've seen a soda can version with a balloon type piston that looks like it was used for a college project, but I foresee many cut fingers with that design.

[Junkie]

That copper piston looks rough, did you sand it to size ? Have you tried submerging the WHOLE engine in HOT water to check for air leaks ?

If you're looking for an easy to build Stirling engine, check out my easy to build Stirling engine fan, see my signature (my ae site).

[jimlarsen]

I'm looking for a design that is doable without a machine shop or soldering iron, and using materials readily available at local hardware stores for under $25 or so.

I think I have just what you need! Check out these engines running on Solar Power:
http://www.youtube.com/16strings

They are built from ordinary materials and do not require a machine shop to build. There are three designs in the book, and each can be build for just under $30. They are built from Acrylic and Aluminum. But it would be very easy to make them from wood instead of acrylic.

The book is available at http://StirlingBuilder.com.

Jim Larsen

[speedless]

Hi
I didnt see this at first,but
The heatchamber-can and watercooling-can should be closer to the powerpiston.
See org.plans.
Jan

[rammstein]

If you disconnect the power piston and pull on the piston a little and then release it ,the piston will shoot inwards fast due to the lower pressure you created by pulling the power piston.
If you don`t have that, the engine has a big airleak somewhere and will not run well.

[dwzavaleta]

I made a few changes to my walking beam Stirling based on several comments from this forum and finally got it going. Changes were:
- used steel wool displacer instead of tomato paste can
- replaced displacer piston bushing with bicycle spoke nipple drilled out to receive a spoke used as piston rod.
- used bottom portion of soda can as top for the displacer cylinder.
- improved flywheel axle using aluminum spacers and washers to fit nylon T-bushings through the wheel.

Many thanks to all of you for your help!