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That looks really good! How tight is the piston radial clearance? Commercial engines use low friction coatings on the piston, and maintaining tight clearance can be important for efficiency (and tricky).

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Hi Lars,
Just checking in... did you finish building your water pump? I'd be interested to see how it turns out.

-Chris

PS That's a cool Mercedes!

Yepitsadam,
That's a very neat model engine! It looks like it's all there... would you mind posting a video if your brother gets it running?

Chris
Cincinnati, Ohio

That's a neat engine! I wonder if some steel wool in the tube between the hot end and cold end would improve your power output.

Chris

Thanks kennethkye,
What software do you use for CAD? Did you end up making an interference engine?
If you'd feel comfortable posting your drawings, I'd be interested in seeing what you came up with.

-Chris

Okay, I understand now. The electric water pump is driven by your peltier elements, which use the exhaust heat from your Stirling engine. That's really neat! Regarding the batteries: How much heat does it take to run your engine? Maybe your burner produces 60 watts worth of heat? ...that may take a ...

Lars,
Two things:
1. The engine with the water pump is very neat. I wonder if you'd get more power out of it if you ran the water across the cold end.
2. The snowmobile movie is amazing and looks so fun. I can see why you can't wait for winter.

-Chris

Ian S C, It's interesting to mention a displacer as a regenerator. Technically, I don't think that anything prevents you from making a regenerator integral to the displacer. I think that it's generally not approached that way because materials which make good regenerators don't like to wobble about....

I often browse Stirling engine videos on YouTube, and I recently came across this cleverly built free piston engine which is made with mostly 3D printed parts and I thought I'd share. I take no credit for the design or build of this engine, I just thought that it was neat. And it's a free-piston eng...

Lars,
Neat stuff! If you attach a positive displacement water pump to your engine, you can roughly measure engine horsepower with the flow rate and pressure head.

I think the equation is: HP = QxH/3960

-Chris

I've been staring at this for a few minutes now, and I'm not sure that I understand how it works. It looks like you have two cylinders rotating eccentrically around a fixed cylinder. Maybe a free body diagram and/or several frames to show how everything moves would help?

Very cool! Is that a repurposed electric motor that's generating your electricity?

-Chris

Hi kennethkye, If you forgo a regenerator, I think it's possible to make an interference engine. As Ian S C said, you will need to lay out engine and make sure it all works. You'll want to slosh all of the working fluid into the expansion space somewhere near the point of maximum compression... so t...

Hi kennethkye, The geometry of the traditional beta Stirling engine will somewhat prevent the displacer and the power piston from sharing the same portion of the cylinder. Remember that there is usually an annulus where the regenerator resides in a beta stirling engine. Of course there are ports in ...

Hi Flash, why are you using plain bearings in the Ross Yoke, you would eliminate the oiling system, and reduce friction by using sealed ball races. If you want efficiency, why are you not pressurising it? If you have not done so all ready, it would be worth down loading Andy Ross's book "Makin...