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Hello,

I want to design a rhombic drive for my beta sterling engine.

I've did a lot of research however am not able to find a clear approach on how to do the calculations.

Anyone who can help me?

With best regards,

JR

JR, no calculations, I'm in the process of building a rhombic, the ratios are the same as for any BETA motor 1.5 : 1, the displacer length3 x diameter. I found after I was just about finished that I had to reduce the diameter of the power piston to get the right displacement, as it happened I had a suitable piston, and just needed another cylinder liner(I'v now got a spare piston and cylinder). I'v got to seal the hot cap to it's flange, so it can be bolted to the cold end. And then I have to design a heater, it will be a gas burner.
Off topic, I,m sure it's possible to design an ALPHA motor in concentric form as in the BETA type. It would require a transfer port from the hot side of the hot piston to the cold space, this could be through a regenerator. At least this way both cylinders would be the same diameter. In that form the hot cap should be shorter than in the BETA motor, the Heylandt Crown on the hot piston would be only 1 to 1.5 x the diameter of the piston.
Ian S C

Hello Ian,

I think I need to rephrase my question.I was referring to the calculations of the rhombic drive itself.

I found a nice article that describes how a rhombic drive works and how to calculate certain values: Article.
What calculations did you use to do the calculations of d1, d2, d3, d4 etc.. ?

Do you have equal values foe d1 and d2? and for d3 and d4? The base paramaters used in the article show minimal difference.

I think I'll use their base parameters as a starting point.

Regards,

JR.

Hi JR,

I used the original publication "The Philips Stirling Thermal Engine" of Roelf Jan Meijer (original invention and intensive analysis of the Rhombic Drive Mechanism)
which you can find free in the net.
If you search a bit you will find a lot in the net.
Also a good explanation is in the Book "Thermodynamics and Gas Dynamixs of the Stirling Cycle Engine" of Allan J Organ.

Greeetings

Ralf

I used the original publication "The Philips Stirling Thermal Engine" of Roelf Jan Meijer (original invention and intensive analysis of the Rhombic Drive Mechanism)