swept volume help

Discussion on Stirling or "hot air" engines (all types)
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larsinist
Posts: 123
Joined: Sat Mar 08, 2014 10:01 am
Location: Northern Norway

swept volume help

Post by larsinist »

I need to build new power piston, cause i am a noob with math, i think the power piston shall be 1.5 times bigger than the swept volume,am i right??, but how to i calculate the swept vulume, i am such a noob at math,but i really try to learn.my machine is a alfa,i think..hehe

Lars
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: swept volume help

Post by Ian S C »

If your motor is an ALPHA it must have two fitted pistons, and both cylinders have the same volume. If it is a BETA motor, the displacer and power piston are in the one cylinder, and if it is a GAMMA motor the displacer, and power piston are in separate cylinders. The latter two types have a ratio of 1.5 : 1between the two sides of the motor.
To calculate the volume of a cylinder: Pi(3.142) x R(radius)squared x H(height) = volume. It isn't until we leave school that we find out why we should have taken more notice in maths class.
Ian S C
larsinist
Posts: 123
Joined: Sat Mar 08, 2014 10:01 am
Location: Northern Norway

Re: swept volume help

Post by larsinist »

I have a Gamma i think, i know how to calculate the ccm of a cylinder,i think i understand the swept volume now, cause i read about it yesterday, btw:i think pi is 3.1415

Thanks

Lars
larsinist
Posts: 123
Joined: Sat Mar 08, 2014 10:01 am
Location: Northern Norway

Re: swept volume help

Post by larsinist »

so when you say that i need to have ratio of 1.5 : 1between the two sides of the motor.does that mean that the power piston should be divided by the cylinder size by 1.5??

Like my engine has a Radius on 18,75mm(Half the diameter) and 111mm lenght,so that will be 3.14x18.75x111=6535,125,does that means that my engine has 65cmm?? or am i totaly wrong?
and my power piston should be 65/1.5=43.3cmm..

Sorry for being a noob
Lars
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: swept volume help

Post by Ian S C »

Don't worry I'm easy confused. Yes I think your right in your calculations. You only need 3.14 for pi, unless you are getting really fussy.
Ian S C
larsinist
Posts: 123
Joined: Sat Mar 08, 2014 10:01 am
Location: Northern Norway

Re: swept volume help

Post by larsinist »

so then i will make a power piston that is about 7,4mm long, and 37.5 wide, that should be ok i think.....

Thanks for help ian s c
larsinist
Posts: 123
Joined: Sat Mar 08, 2014 10:01 am
Location: Northern Norway

Re: swept volume help

Post by larsinist »

I measured the rpm, and i doubled it, i got 450rpm now,with the small power piston, i need to find something to make the bigger power piston from

Lars
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