Rotary Displacer Stirling engine

[tbray___2369]

Hello All!

My son has a science fair coming up and we decided that a Stirling
engine would be a good project. We have looked at the various tin
can engine plans availabe on the web. First we looked at the very
simple unit that utilizes a balloon for a diaphram. Then we looked
at the Walking Leg Stirling made from a paint can. Finally we found
this: http://www.bekkoame.ne.jp/~khirata/english/rot_se.htm

We have built the cylinder from tin cans. We made the rotary
displacer from balsa wood. The power piston is an old used R/C plane
piston in a brass tube. Technically, we understand the principles
well enough. Mechanically, we need help finding or making the
crankshaft to attach to a 1/8" brass main shaft. Also, one thing
that isn't perfectly clear in this diagram is how do we set the power
piston 90 degrees from?? With the rotary displacer, the air gap or
free air area removed from the displacer is where the air/fluid would
reside. The power piston will rotate the displacer to move the air
to the cold side. So, my power piston is 90 degrees out from what?

#Tony

[stan.hornbaker]

There should be an approximately 90 deg. angular distance from the high temperature position of the displacer to the top dead center of the piston. Try locating the crank pin on the horizontal centerline of the cross section shown. The crank disk is shown as a cylinder in the main x-sect. For best operation the angle may have to be adjusted ahead or behind the dead center positions as well as the crank throw.

Go to the site map and review all of the tutorial type materials for how a Stirling engine works and that may help clarify things.

[tbray___2369]

Thanks William. I am thinking I might be able to seal my cans together with muffler tape temporarily until I find the optimum crank throw and angle. Then I can permanently seal them with high-temp epoxy.

#Tony