Rotary Displacer Stirling Engine

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Category:

Science & Technology

Tags:

• Stirling
• Engine

[whotoinfinity]

d909... could you please describe how the displacer was made? Or would it be a hassle to do a follow up video showing it was made?

Either way, thanks in advance and thanks for this film.

[dgreene909]

The displacer was glued up from layers of blue styrofoam that is used to insulate houses. I used a pivot pin as a guide to cut pieces out on a band saw (hot wire or scroll saw would work also). Using the pivot pin mark as a reference, I drilled each piece and used the axle to hold everything in registration while the glue set. The displacer was balanced with steel wire pushed into the soft foam. when balanced, the displacer would roll on its axle between two straight edges without bias.

[pirondinimarco]

I have made one of this prototype but my don't works!

[dgreene909]

To get the motor to run at all (like most Stirlings) you have to really pay attention to friction. This model has teflon sleeves pressed into the acrylic ends. Also, I polished the axles with lapping compound. It is also necessary to counterbalance the displacer. Otherwise, the displacer lobe will just fall to the bottom and stay there.

[dgreene909]

Phasing is adjustable by moving the crank arm on the displacer axle. In the video, it is somewhere around 90 degrees out of phase with the displacer (theoretically where it should be). I have found that it will run just about as well 180 degrees out (piston top dead center with the displacer bottom dead center). In this configuration it will run clockwise or counter clockwise equally well.

[kens97sto171]

Very nice design. I think the smoothest, and most quiet I have seen. I have never seen any Stirling self start, It looks to me like the balloon may be a little too flexible, you can see it puff up a bit before the rod moves upwards, you may be loseing some power there. mabye try some silicone, or even a real cyl/piston type. or, could make two engines, and put them together, it might self start, yours moved more than any other I have seen when you applied the heat.... REALLY GREAT JOB.

[dgreene909]

You are right about the baloon, the flexible part of the diaphram is much too big. This causes a loss of power as well as a timing lag. I think that I will install a rigid center (50% or so of diameter) next time. I also like the idea of a multiple rotor self starter.

[trudgechr]

where is the regenerator??

[trudgechr]

very nice my friend,i like the simplicity of this design and this is on my next build list.excellent!!!!!!!!!

[MilanKarakas]

At first sounds like great idea to make rotary displacer. But, after a while I realized that this can cause mixing hot and cold air - lowering efficiency. Power piston should 'experience' cold and hot air alternatively, but inside cylinder with piston, not in temperature gradient area.

[GoodByeKyle]

beautiful :D

[technology49]

I used blue styrofoam and when i put a candle it melts

[davidfuchs42]

Simple suggestion, glue a flat piece of cardboard to the top of the ballon. Leave about 1/3 the dia of the ballon showing around the outside. It will run faster and be more efficient.

[snoopdog68]

Thats a dandy, its too cold in my shop to go play with fun stuff.

[TheGoodInventor]

1 dislike?

show yourself you asshole

[piespokladowy]

*****

[yellowmetalcyborg]

great engine!