Stirlingengineforum.com

I am not having much luck im getting closer but how tight does the piston need to be to have a good vaccum. i made a piston out of j&b weld. sometimes steam will come out but it won't move the piston is slides easy.

Hi,

I'm not sure I understand what you mean by vacuum.

The power piston/cylinder for my "ugly duckling" version of the walking beam stirling is a glass/graphite matched set I bought from Airpot. The smooth operation of this setup is amazing. IF you have smooth operation and the piston makes a good seal then the engine should run. Of course one MUST generate sufficient heat difference between the ends of the displacer. Please provide us some more details if you can and we will try to provide more advice.

Where is the steam coming from? Maybe the displacer head is leaking water into the displacer chamber?

Balance in the flywheel/beam section is important as well. My engine won't run without an offset weight on the flywheel.

Roger

I just got a piece of alumn. and it slides easy but doesnt provide a good seal. i am going to try putting a then coat of j&b weld on it or try to find a tighter piece of copper .. i thought it was steam but i think it is fog from the ice water i put on top... i added some counter weights to my fly wheel and i think that helps... thanks for the help....

Hey,

I was much too vauge about the weight. I found that to offset the mass of the displacer I had to position this weight opposed to the crank pin. I used a magnet, as I have a steel saw blade as a flywheel , and repositioning was (is) easy. Your engine may be different in its needs, so experiment.

Just keep at it and the engine will run. I had all sorts of issues with mine before it got it going, and have made several refinements since.

When I first heated my engine I too saw some smoke seep around the power piston. In my case it was the coating inside the displacer cylinder cooking off. This distilled off onto the walls of the power cylinder and I had to swab this off with alcohol as it was really sticky and made the piston bind. I've also seen a little condensation derived fog in my glass cylinder at cool startups. This has since stopped as I feel it was a result of the high humidity we have here in Arkansas trapped during assembly.

Keep at it dude, it'll work!

Roger

Rodger,

I think you might be right about the smoke. I run into that problem from time to time about the power cylinder "gumming up". I just tell them to clean it out with Acetone or something. It goes away after a while.



wardle3,
Vaccume is only half of the problem. Pressure is the other half. This is not a vaccum engine per say, but it does have vaccum as half of its cycle. A atmospheric or "flame sucker" engine is a vaccume engine. It's entire cycle is on vaccum I think.

DB