Converting an LTD stirling to a stove fan - hopefully

Discussion on Stirling or "hot air" engines (all types)
Stroller
Posts: 156
Joined: Sat Apr 06, 2024 1:31 am

Re: Converting an LTD stirling to a stove fan - hopefully

Post by Stroller »

Thanks Matt, I'll study the graphs and software when I find time.
For now, more practical matters are pressing.

The piston on my LTD stirling isn't as leaky as I thought it would be. I've just had the engine apart to tinker further with the temporary displacer, so I checked the iron piston clearance by setting it partway down the iron bore and pouring some 95% alcohol in to see how fast it would leak past the piston.

It didn't.

The displacer rod is leaky though. How should I set about making a low friction seal for that I wonder? Vaselined leather? There's a small recess in the underside of the top plate where the displacer rod guide sleeve is screwed on. I can stuff some sort of seal in there. Can anyone tell me what the best material to use is please?
Stroller
Posts: 156
Joined: Sat Apr 06, 2024 1:31 am

Re: Converting an LTD stirling to a stove fan - hopefully

Post by Stroller »

Well that's a big improvement. My temporary displacer is a bit heavy at 110g but the 6g of wire wool around the edge seems to help add some regen, and a 9g coin taped to the displacer counterweight has improved balance.

Here's a short clip of the engine running on my workshop stove. Hot side 142.5C 'cold side' 55C. 133RPM. The engine is silent. The noise in the background is the workshop diesel heater blasting away. Still only 10C outside here in the north of England.


https://www.youtube.com/shorts/51Rp12u2xNE

Good enough to run a fan on the woodstove.

Now to put the rest of the screws back in and shelve it while I think about the next even better displacer. I need look in my materials boxes for that 1/4" dural plate I bought 10 years ago too. I'll be needing it for the upcoming high temperature compressor conversion project.
VincentG
Posts: 1057
Joined: Tue Feb 21, 2023 3:05 pm

Re: Converting an LTD stirling to a stove fan - hopefully

Post by VincentG »

Regardless of power output that is a really nice engine that will look great on the shelf for now haha.
Stroller
Posts: 156
Joined: Sat Apr 06, 2024 1:31 am

Re: Converting an LTD stirling to a stove fan - hopefully

Post by Stroller »

Thanks Vincent. While the missus is away for the weekend I'll see how it looks on the mantelpiece :)
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