A Homemade Sidewinder-Walking Beam Hot-Air Engine

By Tom Humpert
December/January 1998
Add to My MSN

The power cylinder on Tom Humpert's homemade sidewinder-walking beam hot-air engine.

Content Tools

This is the engine, which I call the Sidewinder-Walking Beam Sterling Cycle or hot-air engine, was built last winter.

Some of the component parts are remanufactured to do the job. If you look closely, you'll recognize some raw materials.

The flywheel came off an old printing press. The water hopper on the displacer side of the engine is a top of a 100-pound propane tank turned up-side down. The bottom of the displacer side is a 40 pound propane tank.

The bottom of the power cylinder is a freon tank to hold the oil for the power piston for lubricating and cooling. The power cylinder is a 6-inch bore hydraulic cylinder for a dump truck box. The rest of it is 50 cents per pound at ALRO steel.

At the shows, I run it about 80 to 150 RPM. I have a cast iron cook stove burner, 15,000 BTU in the engine. For the amount of work it does at shows that's plenty of heat. The engine weight is 800 pounds, height is 6 feet. Flywheel weight is 150 pounds, diameter is 3 feet. Power piston/cylinder bore is 6-1/2-inch with a 7-inch stroke and the displacer piston cylinder has an 8-inch bore by 8-inch stroke.

Also, I have this picture of my "Tom Humpert Toy Box." This is what I show out of. Depending on the type of show, it tells me what to bring. I have a lot of neat things for that Toy Box.




Gas Engine Magazine F/M 16Gas Engine Magazine is your best source for tractor and stationary gas engine information.  Subscribe and connect with more than 23,000 other gas engine collectors and build your knowledge, share your passion and search for parts, in the publication written by and for gas engine enthusiasts! Every month Gas Engine Magazine brings you: restoration stories, company histories, and technical advice. Plus our Flywheel Forum column helps answer your engine inquiries!

Be sure to take advantage of the Square Deal Subscription Program.

  • No Missed Issues.

  • No Renewal Notices.

  • No Additional Cost.

The Square Deal Subscription Program is designed as a paperless transaction with automatic renewals at a preferred low rate.   With advanced electronic notification, a 100% satisfaction guarantee and an easy opt-out plan, the Square Deal Subscription Program is the best value, risk free, eco-friendliest way to subscribe.

(* indicates a required item)
Canadian subs: 1 year, (includes postage & GST). Foreign subs: 1 year, . U.S. funds.
Canadian Subscribers - Click Here
Non US and Canadian Subscribers - Click Here