Thanks Phil, I love these wee mechanical puzzles. Basically as the rotating cylinders piston moves it causes a change in pressure in the glass bit (hot cap) this change acts on the displacers shaft making it move this then moves the hot air to the rotating cylinder (power cylinder) as the air is heated it has a positive pressure this pushes the power piston.The flywheel inertia keeps the thing going
Bet you're glad you asked
Only a vicar could come up with the original idea Rev Stirling
Sounds simple but it has taken nearly two years worth of swearing to get it to run and its only due to Huib Visser in the Netherlands that she finally became a runner.
The problem was standard reamers gave too much clearance so I had to make some tool makers reamers 0.0004 undersize and make all the pins and bushes from hardened steel. All lapped in with tooth paste. All getting a wee bit to accurate for my shop
I used to build steam including flash but now find these things more challenging although I keep building the odd steam launch now and again
Keep well
cheers