Stirling engines without flywheels

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nufan_wfk
Posts: 3
Joined: Wed Aug 30, 2006 11:09 pm
First Name: Kevin
Last Name: Thayer

Stirling engines without flywheels

Post by nufan_wfk »

Greetings, all. I've been interested in Stirling engines lately, and
have decided to build a model for myself.

I generally don't like the complexity of sealing pistons and the
flywheel mechanism, as sealing is hard to do without good equipment,
and the flywheel makes for a lot fo seals.

I've done some calculations, and it looks like, with two alpha type
engines, interconnected, the flywheel is no longer necessary, as each
engine will push the other along at the appropriate time.

I made a diagram, see

diagram


the 'pistons' will be rubber or plastic membranes, deformed so that
they are shaped like a pie-pan, and the air pressure can push them
this way or that.

Is there a fatal flaw with this design? Any tips before i build?

thanks!
-tmk
stan.hornbaker
Posts: 532
Joined: Thu Jun 20, 2002 6:01 pm
First Name: William S.
Last Name: Hornbaker

Response to Stirling engines without flywheels

Post by stan.hornbaker »

"l've made a number of Stirling engines and l would suggest you build a Stirling engine from a plan so you know if it is made properly it will run. Then the second engine you build you have a basic knowledge on how a Stirling engine runs.
If you have a lathe then sealing should be no problem.
lf you don't have a lathe then build the tin can Stirling engine re free plans from the internet.

"In answer to your question you'll need a fly wheel regardless"


C. R. Punshon made the above suggestions via email.
W.S.H.
rmcpb
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Joined: Sun Oct 22, 2006 3:11 pm
First Name: Rob
Last Name: McPaul-Browne

Response to Stirling engines without flywheels

Post by rmcpb »

From what I understand the flywheel stores the energy produced in the engine and applies it to moving the engine through all phases of its motion leaving the excess available for work. If you had offset cylinders and no flywheel a lot of the energy produced by each cylinder will be used to push the other cylinders through their cycle with no momentum stored for other work.

That is one reason internal combustion engines have flywheels.
stan.hornbaker
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Joined: Thu Jun 20, 2002 6:01 pm
First Name: William S.
Last Name: Hornbaker

Response to Stirling engines without flywheels

Post by stan.hornbaker »

Rob McPaul-Browne wrote: "From what I understand... If you had offset cylinders and no flywheel a lot of the energy produced by each cylinder will be used to push the other cylinders through their cycle with no momentum stored for other work."

If you were to build an engine, sans flywheel, it would NOT run. It is not seen as pushing the pistons/cylinders as much as maintaining continuity of motion and smoothing out the pulses from individual piston/cylinders. In the case of an ICE the flywheel includes a harmonic balancer to improve the smoothness of rotation of the flywheel/crankshaft.
joefish711
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Joined: Tue Jun 30, 2009 9:26 am
First Name: Joseph
Last Name: Nyleen

Response to Stirling engines without flywheels

Post by joefish711 »

William is correct. The flywheel is necessary to store part of the net system energy in it's inertial moments. This is also why many alpha type engines require an initial "push" on the flywheel to get the action started. (I have seen them auto-start using magnetic repulsion, but it is a slow process to build the required inertia). If you skip the fly wheel, and try to use another set of pistons, you are required to add more energy to perpetuate the cycle. This is counter productive, in either LTD engines or attempts at energy producing engines.
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