Does the Balloon need to travel same distance as displacer?

Discussion on Stirling or "hot air" engines (all types)
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Insainhouserecords
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Does the Balloon need to travel same distance as displacer?

Post by Insainhouserecords » Mon Feb 18, 2013 11:41 pm

This is a beta can engine. I'm trying to decide if my crank is right. If my displacer lifts 1.5in, should the balloon also lift that much in retrospect?

Ian S C
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Re: Does the Balloon need to travel same distance as displac

Post by Ian S C » Tue Feb 19, 2013 4:08 am

If your displacer moves 1 1/2", I think 3/4" would be a place to start, but 1 1/2" seems a big stroke. Is this the stroke recomended in the plan of the motor? Ian S C

Insainhouserecords
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Re: Does the Balloon need to travel same distance as displac

Post by Insainhouserecords » Tue Feb 19, 2013 8:09 am

Lol, there was no motor plan. I looked at the other engines being built and started to build from scratch under my own assumptions and common knowlage of physics.

Junkie
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Re: Does the Balloon need to travel same distance as displac

Post by Junkie » Tue Feb 19, 2013 12:59 pm

The balloons in my models usually only move about 5 - 10 mm total stroke. The displacer usually 28 - 35 mm stroke. These are coke can models.
http://www.scraptopower.co.uk My web site, Stirling engines and AE stuff.

theropod2
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Re: Does the Balloon need to travel same distance as displac

Post by theropod2 » Tue Feb 19, 2013 5:45 pm

Insainhouserecords wrote:Lol, there was no motor plan. I looked at the other engines being built and started to build from scratch under my own assumptions and common knowlage of physics.
See you other thread, please.

R

Hopper
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Re: Does the Balloon need to travel same distance as displac

Post by Hopper » Wed Feb 20, 2013 8:19 pm

Insainhouserecords wrote:Lol, there was no motor plan. I looked at the other engines being built and started to build from scratch under my own assumptions and common knowlage of physics.
This may be your problem. There is more to these engines than meets the eye. Best to start with a tested and proven existing plan, then move on later to your own designs. There are plenty of Coke can plans on the net.
Here is a good one
https://sites.google.com/site/reukpower ... ing-engine

Insainhouserecords
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Re: Does the Balloon need to travel same distance as displac

Post by Insainhouserecords » Thu Feb 21, 2013 10:26 am

Yea, that was the first type I tried. Idk what materials the guy used but no glue sticks to balloons and his wire bends aren't descriptive enuf. I guess I really need a diagram or template because looking at what he does and trying to replicate it are two different things.

Hopper
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Re: Does the Balloon need to travel same distance as displac

Post by Hopper » Sun Feb 24, 2013 9:38 pm

Insainhouserecords wrote:This is a beta can engine. I'm trying to decide if my crank is right. If my displacer lifts 1.5in, should the balloon also lift that much in retrospect?
Probably not.

Hopper
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Joined: Fri Feb 08, 2013 6:54 pm

Re: Does the Balloon need to travel same distance as displac

Post by Hopper » Mon Feb 25, 2013 12:40 am

Insainhouserecords wrote:This is a beta can engine. I'm trying to decide if my crank is right. If my displacer lifts 1.5in, should the balloon also lift that much in retrospect?
No. That would be stretching the rubber too far.
If the Displacer moves 1.5 inches, the rubber diaphragm needs to move about half an inch.

So your crankshaft should have one offset of 3/4" inch for the displacer and one offset of 1/4 inche for the rubber diaphragm.
The two offsets should be at 90 degrees to each other, so that when the displacer is at the very top, the diaphragm is flat in the middle of its movement.

Insainhouserecords
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Re: Does the Balloon need to travel same distance as displac

Post by Insainhouserecords » Thu Feb 28, 2013 10:43 pm

Thank you for your help everyone!

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