[jeremy1375]

GEET has free plans for small engines, but I don't think they're refined enough to run any load.

http://geetinternational.com/GEET%20...ans%5B1%5D.pdf

Smokey Yunnick's hot vapor engine has been a long time interest of mine. Pressurized gas vapor heated to 450 degrees is one reason I'm inclined to not try it, but it's an interesting and counterintuitive idea.


http://www.hotrod.com/techarticles/e..._vapor_engine/