The Little Engine that Did

A Chance Encounter Leads to a New Appreciation

Little hot-air engine

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A.B. Gardner's little hot-air engine, made entirely by hand, is proof of just how simple the engine hobby can be when you put your mind to it.

I have had many hobbies in my time, but if I had known old steam, gas engines and hot air engines were so much fun, I would have gotten into the hobby 20 years ago.

At the Lone Oak Lions Club Annual Antique Steam and Gas Engine Show in Paducah, Ky., last year, I walked up on a display table where a fellow had a tin can Stirling hot air engine running. That was the first time I had ever seen one, and I was instantly fascinated with what powered it. I studied the details of its construction, because I knew I had to build one.

When I got back home to Tennessee, I called my good friend, Don Kelly, of West Memphis, Ark. Don, who's a machinist, happened to have some plans on how to build hot air engines, and he gave me lots of good pointers on how to fine-tune it and how to make it run at full capacity. After about 6 weeks of trial and error, I finally built one that would run.

When you see the water bath (top left of the flywheel - I guess you could call this a radiator) that cools down the heat from the displacer, and when you see all the moving parts, like the rocking arm, piston rod, power piston, linkage, and flywheel, you know you are looking at a real engine.

The little engine has a vertical displacer piston, a horizontal power piston, and a 1-3/4-inch stroke. After clocking the flywheel, at 140 rpm, I had to see if it would pull an accessory, so I got busy and made a small fan, a crank flywheel and some pulleys. After great anticipation and some adjustment of the pulley belt, the little engine pulled the accessories at a speed of 60 rpm. What a great project to build and a fun way to pass the time.

Contact engine enthusiast A.B. Gardner at: 2553 Highway 59W, Covington,TN 38019