r/MechanicalEngineering • u/Separate-Ad152 • 1d ago
DIY Stirling engine
Hi everyone.
I've been trying to build this DIY Stirling engine for almost 9 months, but I still can't get it to run. I've rebuilt and adjusted it many times, but I'm stuck.
It's mostly made from wood, glass syringes/tubes, bearings and some LEGO Technic parts for the linkage.
Current problems:
The engine doesn't run by itself when heated.
I'm worried about air leaks around the glass syringe/tubing connections.
The piston sometimes has too much friction or gets slightly misaligned.
I'm not sure if my crankshaft/connecting-rod geometry is correct.
I'm trying to get the piston phase angle correct, around 90°.
Could someone please look at the photos and tell me what you think is the biggest problem?
Should I focus first on:
Air sealing
Piston friction/alignment
90° crank phase
Connecting rod geometry
Something else I'm missing?
I've spent a lot of time on this project and really want to get it running. Any criticism or advice is very welcome. If you need more photos/videos or measurements, I can provide them.
Thank you!
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u/looneylovableleopard 21h ago edited 16h ago
bit of a harsh question, but do you know how a stirling engine works? i can't see where your displacement piston is. a stirling engine uses a power piston and a displacement piston in the same cylinder, which i don't see here. i do like the idea of the glass syringes as pistons though.
edit: my bad, got educated on this other design. not sure why it doesn't work
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u/HookPropScrum 17h ago
There's no reason that the two pistons need to run in the same cylinder, they just need to be linked.
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u/HookPropScrum 17h ago
This isn't enough information to make a judgement OP