Stirling Engine without Displacer Piston

Discussion on Stirling or "hot air" engines (all types)
StirlingEnthusiast
Posts: 5
Joined: Mon Feb 06, 2017 8:28 am

Stirling Engine without Displacer Piston

Postby StirlingEnthusiast » Mon Feb 06, 2017 8:33 am

Hello all,

I was wondering if, to eliminate the possible air leak and maintenance of the Displacer piston, I could simply eliminate it and have a free displacer hooked to the sides of the tube with a string. The power would come from two balloon skins on top of my two cans expanding and contracting.

Is this feasible? Will it work well?

*Sorry if I sound dumb, it's because this is my first time in this field.

Thanks,
Enthusiast

Ian S C
Posts: 1953
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Stirling Engine without Displacer Piston

Postby Ian S C » Tue Feb 07, 2017 2:29 am

You can run a Stirling Engine with a free displacer, but you will have to look up Ringbom hot air motors.
It is possible to do away with the crankshaft completely with the free piston motor, a spring system takes place of the fly wheel, and every thing just bounces up and down.
The hot end of the displacer cylinder can either have fins for air cooling, or as I did, form a water jacket around it and water cool it.
Which ever way, there is still a leakage path to atmosphere via the rod on the displacer.
Ian S C
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cbstirling2
Posts: 106
Joined: Sat Dec 17, 2016 9:35 pm

Re: Stirling Engine without Displacer Piston

Postby cbstirling2 » Tue Feb 07, 2017 6:19 am

Is that engine pictured a ringbom design?
CBStirling2

Ian S C
Posts: 1953
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Stirling Engine without Displacer Piston

Postby Ian S C » Thu Feb 09, 2017 2:37 am

Yes it is, this is a famous design, being one of the first of this type of motor to be built and published in Engineering in Miniature in 1982.
This little one was built from parts of my first Stirling Engine.
Ian S C
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Ian S C
Posts: 1953
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Stirling Engine without Displacer Piston

Postby Ian S C » Fri Feb 10, 2017 3:05 am

You can of course do without the displacer all together, and build an engine known by a number of names, such as Thermo Acoustic, Pulse Engine, Laminar Flow, Lag Engine. There are a number of threads on these motors on this site.
Ian S C


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