Eighteen years ago for my father's 83rd birthday, I built a hot air engine using my own aluminum castings, skate ball bearings, a graphite piston, and many borrowings from my scrap pile. It was a very rushed 2 week project, since I had little idea of the complexities I was getting myself into. I worked long into the nights. Nevertheless I finished the little engine the night before leaving to see him, and got the bare engine to run, rather impressively, by heating the displacer cylinder over the kitchen stove. I quickly added a channel Iron base, a firebox out of square tube, and a smokestack out of a brass sink drainpipe. The firebox even had a door.
When visiting him a few states away, I brought a small can of Sterno as a heat source, and this fit into the firebox, and luckily was enough to power the engine as well, running steadily. All was well!
Because we had to return home the next day, I took some pictures of the engine on a rather fancy table. The engine was named "No. 83" in honor of my father's birthday. Those photos were all I had of the engine for many years, and I really regretted I didn't have more time to run it, improve it, and try out the many ideas I had as experiments. In fact the original intention was to run it with wood as a fuel, and the firebox and stack were built with that in mind. But that never happened.
Not to go into too many personal details but my father later had a bad fall, was hospitalized and sedated for a week, lapsed into partial dementia, and my brother, an heroin addict and ex-con, took over his life. My father passed away, and my brother took everything, including the little engine. That was the end of it, so I thought.
My nephew, a kind person, recently returned the engine to me after his father, my brother, had also passed. It had been 18 years. My brother had pronounced my engine non-workable after trying and failing to run it once for my father. He had no concept of what a hot air engine really is or how it works. After my father died, my brother had left No. 83 in the corner of a garage on the bare concrete to rust.
The .008" walled displacer cylinder had been overheated and ruptured. The fire door was missing. No. 83 was in sad shape.