Stirling doesn't work

Hello everybody,
I have got a little Stirling engine from our school's experimental
equipment, which I need for a lecture. But unfortunately it doesn't
work. I heated the cylinder with the original small alcohol burner,
later with a gas burner, kicked the flywheel many times, but it doesn't
start.
I'm unsure whether the engine ever has worked in a physics lesson, in
any case the engine is nearly new. It is a one-piston engine and can be
seen on
formatting link
(not my website) on the
very bottom.
Can anyone help to get this machine work?
Thanks for your attention,
Michael
Reply to
Michael Käppler
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Well, the piston has to be a pretty tight fit in the bore, the displacer generally is designed as a loose fit and the working fluid passes around the displacer from the hot to the cold side. The piston and displacer need to have a 90 degree angle between their top dead center positions. Is there much friction when it is turned by hand? Thses engines are so simple, that if they are just assembled properly, they just about can't NOT work! The displacer rod needs to be a pretty tight fit where it enters the cold side of the displacer, or it will let all the pressure out, instead of allowing it to work against the piston.
I think those are the only things that could keep such an engine from running.
Jon
Reply to
Jon Elson
Critical points to ponder are the absolute freedom of all movement (check the alignment of the rods where they pass through the packings, and that the crankshaft is free) and check that the packing on the rod is pressure tight while still allowing free movement. The power piston must be absolutely free, while still being airtight.
Cheers Trevor Jones
Reply to
Trevor Jones
The first thing I would look for is a leaky gasket or connection somewhere. Stirling's must be virtually airtight to run properly. I'd check the junction between the cold end and hot end as well as the power piston fit. Any leaks anywhere will prevent proper running.
Robert
Reply to
Siggy
I think the angle is the problem, I've recognized that the flywheel locking is loose, therefore the phase angle can change unpredictably. Well, I will tie them today and adjust it at an angle of 90 degrees...the displacer has to be at his top dead center position 90 degrees later than the power piston, right?
Michael
Reply to
Michael Käppl
I have the single flywheel version of the Solar engine you've got. It's suffered a lot of abuse and many hours of use from a teenaged boy, and it still runs.
Be sure that there is no oil on the power piston. Someone may have oiled it. Remove it and wipe it off with alcohol on a clean rag or paper towel. If you get any crud off it, use cotton-tipped swabs to clean the cylinder bore.
While you've got the connecting rod disconnected from the crank, push the piston into the cylinder. You should feel air pressure building up. Release the piston. If it doesn't bounce back, you've got a serious air leak.
The one place you *do* need oil is on the displacer rod. It helps to minimize air leakage. BTW, if the bushing is worn, air leakage may be excessive and the engine won't run.
Checkthe o-ring under the screw head at the end of the power piston. It may be cracked and leaking air.
If you suspect an air leak, see if you can unscrew the hot cap. If you can, (without damaging it) put Teflon tape on the threads and reassemble.
While you have the hot cap off, be sure the engine has a displacer! Someone may have lost or damaged it.
Be sure the power crank and displacer cranks are 90° out of phase.
After reassembly, spin the flywheel. There should be a bit of compression, but other than that, if there's any binding or drag, whatsoever, the engine will not work.
Good luck. Let us know how things work out.
Orrin
Reply to
Orrin Iseminger
Yes, that sounds right. When the displacer is at TDC, all the volume in the displacer cylinder is at the cold side, so it should start to draw the piston back up the cylinder.
Jon
Reply to
Jon Elson

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