Stirlingengineforum.com

Very impressive!

Way back in the '80's I made a batch of hand size hot air engines using CNC wherever possible.

I still have the drawings......

I think my email address is shown.

Cheers
Bernie

I think you are right - like me you already have a fixed stroke for the displacer so you can work it backwards from that point if my theory is correct. i.e the stroke is 1/3 of the length etc. I'm wondering about the thermal conductivity of your brass cylinder and note that some of the smaller engin...

I THINK the displacer length should be about 3 times the diameter and take up about 2/3 of the cylinder length. I'm really no expert on these sizes so treat the info as a rough guideline only!

The clearance should be very small in your case but it must actually clear.

Bernie

My engine has about 3mm displacer clearance on a diameter of at least 100mm so I think you could be right in thinking it's a bit too loose on 10mm.
Don't give up... (I nearly did!)

Hi Doug - you have suffered from the same problem as me in trying to find some ideal design sizes/ratios and I also went for a full metal engine with decent sizes. I'm no model maker or watchmaker! From looking at your excellent pics I think you need to look at the size of the displacer cylinder. Se...

and .... if anyone would like a pic of my efforts to copy a Robinson engine please email me and I will try to send a couple.

Incidentally I have named the engine "Shufti" as it was made from looking at pictures!

Bernie

IT WORKS!!! After some work on the displacer (dumping the pot cleaners) and making it almost airtight my lovely wonderful super duper Robinson type engine finally managed a full cycle and then slowly gathered speed to a continuous RUN. YESSS! Time for a celebration glass methinks... (brilliant way t...

I'm building a Robinson type engine and a bit stuck! My engine has a power piston of 1.25" dia and a stroke of 2" the displacer cylinder is 4.5" dia and the stroke is 1.125" all these sizes were guessed as I have no drawings beyond museum pictures. The displacer is a stainless cu...