Hot Air Engine
Bought as a kit, built by my son, Robert, as a Christmas present for his elder brother.
The kit is intended to be put together using a file, a drill and a hacksaw. However, when there is a full workshop available, you tend to use it.
The pictures below just pick out some of the stages in the manufacture of the hot air engine.
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| The kit of parts as supplied | The connecting rods roughly filed to shape, awaiting the final clean up and reaming of the holes | The bearing block, completed but awaiting the top to be split | Splitting the beating block using a slitting saw |
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| Robert machining the holes in the cool cylinder - there are a lot of holes and the DRO on the mill was invaluable | A lot of holes drilled | ...on all the faces | The flywheel, marked out, awaiting drilling. |
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| The flywheel, drilled. It now just requires a threaded hole for the connecting rod bearing and a grub screw to retain it on the axle | Reaming the end of the displacer rod | Starting to join bits together - this is the cool cylinder and the power cylinder | The completed unit - and it works (but see note below) |
It works (but it needs a lot of heat), certainly more than a spirit burner can supply. I have been in touch with the local "expert" who could find nothing wrong. (The only problem with a lot of heat is that the copper cap to the "hot" end tends to un-silver solder itself! As yet, we haven't solved the cause, but by making a new "hot" cylinder out of solid stainless, we can use a lot more heat as there is no silver solder!
However, the main thing is that It was worth it, my eldest son was delighted with the present on Christmas day.