My stirling won't stir

[clintsims]

Can't get my stirling to work, need help!!
Tries to go a little but won't roll, also the glass tube keeps working its way off

 

[canadianhorsepower]

how Free spining is it
If it's to tight it won't work

 

[portlandron]

These engines have very little power so you must keep friction as low as possible.

If you are using any sealed bearings remove the seals. No grease in any bearings. Flush all bearings with solvent and run dry.

Don't use any oil. Use Graphite powder for lubricating.

The hardest part to get correct is the piston to cylinder - if to tight the engine will not run - if to loose engine will not run.

 

[AussieJimG]

If the glass tube is being pushed off by pressure, that's a good sign.

I agree with the others: minimise the friction and it should run.

Jim

 

[Mechanicboy]

If all is free for friction, the problem is loss of heat in the engine. I can see there is displacer piston of aluminium is made of aluminium bar. Use hollowed aluminium displacer piston or nonconductive material as displacer piston. The length of glass cylinder and displacer piston is too short to make difference temperature between the hot and cold space and can not produce enough pressure developed by heat to drive the work piston.

 

[creast]

It took me a while to get my stirlings to work too .
https://plus.google.com/u/0/b/100807562735804542430/100807562735804542430/videos
Pretty much repeating what has already been said here.
1. Absolute low friction required.
2. Piston fit is critical.
3. Displacer best as a light sealed hollow cylinder.
4. Check for leaks.
I and a few others have used Redex in very very small quantity as a rod lubricant. If you try this and the engine speeds up then it shows the rod seal is too leaky. Never lubricate the power piston , use graphite or make the piston from graphite.
Alignment of the whole mechanism is critical, if you play around making adjustements to the whole alignment you will be surprised how you can find the sweet spot.
Good luck.. persevere.. its worth it.
Rich

 

[Mechanicboy]

Your engine has too short displacer piston hence heat conduction loss caused by the length of the displacer cylinder. The displacer piston/cylinder must be larger than working piston to create more pressure. The wall thickness of displacer cylinder must be thinn as possible to get hot entered into the cylinder with minimal loss of heat from the source of heat such as the candle or the torch lamp. Length of the displacer piston must be decided two or three times of the stroke. Diameter of working piston about 1.5-2 times smaller than diameter of displacer piston. Stroke of piston is same for both displacer piston and working piston. bore/stroke ratio for working piston will be between 1:1 - 1:1,5. It is important that the dead volume in the engine is decreased. Keep all moving parts light as possible.

Use ball bearing on crankshaft and connecting rod for better running the engine.

On larger Stirling engine, i used the piston with sealant made of thinn leather lubricated with sewing machine oil same manner as a bicycle pump piston. Works very well as i am showing the photo of stirling engine as i photographed for about 20 year since. The hermetic box above the displacer cylinder is coolant for the cold side of cylinder.

 

[Longboy]

Your piston length is fine for the stroke. Your displacer cylinder is loose and not sealing. There is no pressure within a Stirling that can push the hot cyl. out. Looks like 3 white seals holding on the cyl. If these are Nylon or Teflon replace them with hardware store O-rings. They need to be this type of pliable material to make the seal. You can test what you have by using dish soap suds on the hot tube mounting and heating up the end of the tube momentarily and you can check any part of the engine that needs to be air tight the same way. As for friction issues, you can remove the con rods one at a time and spin the flywheel. On the hot side its the displacer in contact with the inside of its cyl. The power cyl. is a real pain. you must have the right amount of sealing with its piston with a low friction point. I use glass irrigation syringes as they are fool proof in this area now. Use a drop or two of WD40 on the displacer pushrod at the gland to lub this friction point. My best guess? You have internal air leaks.