brass stirling engine

[larsinist]

I could not get my last small engine to start,and then i found a nice pice of brass,so i started on a new one,it shall have a 40mm bore, and the cylinder shall be 125mm-130mm long,and the displacer shall be 80mm long, and i am also thinking of making the piston in brass, with 1.5mm-2mm clearance between the cylinder and the displacer, does this sound right??

Lars

New stirling.JPG2.jpg (145.1 KiB) Viewed 6470 times

[Ian S C]

Lars, brass on brass is not really a good idea, you would be better with cast iron, steel, or stainless steel.
Discounting cast iron, you should not run like metals together, the friction tends to be high, and under heavy loads they try to weld themselves together, oil tends to minimise the effect.
Don't get too worried, I get a bit carried away with metallurgy, often when we build our motors we have to use what we have, rather than what is best.
I would not use brass for the hot end.
The clearance of the displacer is about right. Ian S C

[larsinist]

i have made som more parts, and the cylinder is done,i will make steel parts after if it will be a good engine, but the brass is what i have now.

stirling brass.jpg (92.78 KiB) Viewed 6441 times

stirling brass2.jpg (74.9 KiB) Viewed 6441 times

stirling brass3.jpg (85.54 KiB) Viewed 6441 times

[larsinist]

Its now starting, but i revs only about 150-prm,and i need to build a better crank,i will update when the machine go better

Lars

[larsinist]

I think i have a to small displacer, i found a airpot,that is about 1.2cm in diameter, and it is about 1.8cm long, so my stroke is about 0.9,can i use to of them??? will it help???

Lars

[Ian S C]

The volume of the displacer is 1.02cc, the power cylinder should have a volume of about .75cc. What size is the power cylinder, and what is the stroke of the piston?
Ian S C

[larsinist]

The power piston is id:23mm and its about 23mm dia,and about 1.1mm deep,the cranck stroke is a total 2.2mm,and the power piston/displacer stroke is 1.1mm..i think the power piston is to small,this is not the finished version of the engine, i only have one bearing,cause i cant fine any more, and the crank is not straight, and i am just testing the flywheel size, with cd disc, i will use aluminum as a flywheel when i get this machine to go better, cause it really should be faster and stronger

See video
[video 425,350]https://www.youtube.com/watch?v=vTxw-h-e__w[/video]

[youtube]https://www.youtube.com/watch?v=vTxw-h-e__w[/youtube]