Why is the stroke of two pistons of 2 types different ?

Discussion on Stirling or "hot air" engines (all types)
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thanh-cuibap
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Location: Việt Nam

Why is the stroke of two pistons of 2 types different ?

Post by thanh-cuibap » Tue Sep 13, 2016 9:05 pm

hello everyone !! anyone can help me ..please !!
explain help me... why the stroke of two pistons of 2 types different ?
at : 12minute
at : 5 minute. 30 seconds

Ian S C
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Re: Why is the stroke of two pistons of 2 types different ?

Post by Ian S C » Thu Sep 15, 2016 2:26 am

I haven't seen the videos yet (on dial up), but there are two distinct types of hot air engine, the GAMMA and BETA are one type, they have ONE piston, and a displacer that transfers the hot air to the cold end, then back again. Then there is the ALPHA motor, this has two pistons, these two are equal bore and stroke, were as the displacer types have a ratio of 1.5 : 1 displacer volume to power cylinder volume.
Ian S C

thanh-cuibap
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Re: Why is the stroke of two pistons of 2 types different ?

Post by thanh-cuibap » Thu Sep 15, 2016 3:26 am

Hi Ian SC !!
I think two engine is the same engine gamma engine , but the stroke differenct , I don't know why !?..

Ian S C
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Location: New Zealand

Re: Why is the stroke of two pistons of 2 types different ?

Post by Ian S C » Fri Sep 16, 2016 1:56 am

Ah, the displacer needs to have a greater volume, either by increasing the stroke over the power piston, and keeping the same bore for both, or use the same stroke for both, and increase the diameter of the displacer cylinder. This formula was the one that Robert Stirling used for his motors 200 years ago.
Ian S C

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