getting it going

Discussion on Stirling or "hot air" engines (all types)
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Joined: Wed Sep 26, 2007 10:23 am
Location: banbury, oxfordshire

getting it going

Post by julian » Wed Sep 26, 2007 10:40 am

HI guys,

I am having a bit of bother. :???:
I am trying to build a stirling engine, but cannot seem to get it going. Can't see a way of including a sketch here, but basically, I have joined two cylinders end to end, one with an ordinary piston to take work from the system, the other with just a double piston head without shaft to act as a displacer (the seals have been removed to allow air flow around it). This second cylnder has then been given a bypass tube from one end to the other, which is filled with wire wool to act as a regenerator. Manually moving the piston does move the displacer, but heating the other end, where the displacer sits, does not move the piston.
Perhaps someone out there can tell me where I am going wrong?

alpha stirling
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Joined: Sun Apr 29, 2007 9:24 am

Post by alpha stirling » Thu Sep 27, 2007 10:04 pm

So if I understood what you were saying, there's no crank or rod or anything moving the displacer piston? The volume of the displacer piston should equal 2/3 of the swept volume of the displacer cylinder and it should equal 1,5 times the volume of the power cylinder... The crank mechanism moving the displacer piston should have 90 deg advance to the power piston...

I can't really do much more unless I see sketch or photo of your engine...
They told me one cannot build a jet engine in garage conditions. I proved them wrong and I was only 16 :P

Don't let people's sayings discourage your creativity!

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Joined: Tue May 16, 2006 5:06 pm
Location: California

Post by SScandizzo » Tue Oct 09, 2007 1:15 pm

Hi Julian,

The biggest issue I can gleen from your post is that the two cylinders are not correctly timed. If you design moves one piston to the top of its cylinder while the other piston is at the bottom of its cylinder, your system is out of phase. That is: one piston should be half way up its cylinder while the other piston is reaching the top or bottom of its cylinder. This is why just about every simple Stirling engine has a crank and flywheel. Without them, you can't get the timing correct or store the kinetic energy produced by each stroke.

Try to find a free web posting site and get a few pictures up so we can give you more help!


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