My First Stirling Engine - 2011

[George_Race]

Here is a picture of my first Stirling Engine finished in 2011.  I purchased the material kit and plans from LMS.  Was a fun build, almost everything was formed up on the CNC.   The cooling fins and burner were turned on the lathe.



George

[chuck foster]

nice looking engine george ............... could we possibly see a video of it running????

chuck

[George_Race]

Hi Chuck, wish I could do that, but I never got it to run!

It really turns over freely and when heat is applied it will try to keep up for a bit, after giving it a hand spin, but slowly comes to a stop after 10 or 15 revolutions.  I know it is working, somewhat, as it will not go anywhere near that number of revolutions without applying heat.

I did plan on replacing the sleeve bearings, where the flywheel mounts, with some small roller bearings to try to give it a bit less friction in that area.   Buy have yet to get to it.

The thing I like about it most is that i finished almost all the pieces with my home made CNC.  And that includes the making of the flywheel and the cam wheel on the other side.

If I ever do get it runnning continuously, I will definitely do a video.
Thanks for your interest,
George

[Ian S C]

   It might be worth running the motor for say an hour with a small electric motor at somewhat less than 100rpm, it's worth putting an ammeter on the motor, and as the motor frees up the current drops.
   Check that there are no leaks (well minimal around the displacer rod).  Also check the displacer its self by sticking it in hot water, and watch for bubbles.
  The piston should drop through the cylinder under its own weight, and stop when you block off an end of the cylinder.  Use no oil on the power piston.
   I get most of the bearings for smaller motors from old VHS recorders, and other electronic gear

[George_Race]

Hi Ian, I have tried most of your suggestions already.  The motor is really very free running.  I suspicion that I do have a leak somewhere.  Someone told me to submerge it in water and put air into the sealed up side port where the cross connection hole was drilled.
I have not tired that yet.
I really do want to put some nice roller bearings in first, and see if that helps.
Thanks for all the suggestions,
George

[Ian S C]

I think I may have found out how to get a photo here, this is my latest, and smallest

[b.lindsey]

Nice looking engine George but I know you would prefer it running too!!  Most sterlings require ball bearings and while a leak could be the problem, it sounds plausable also that the sleeve bearings could be robbing enough of the power to drag it down after the 10-15 revolutions you mention. One or both of those things should get it up and running.

Bill

[George_Race]

Hi Bill, yes I think that ball bearings will be the next thing that I try.  Probably will not be until this winter, when I get a few other projects out of the way.
Will post back here when I get some changes made.
George

[KB]

Nice work George.

When you get the ball bearings, the grease should be washed out too.

Did you machine the ID of the copper tube?

[DaveH]

Very nicely made George 
 
DaveH

[George_Race]

Kevin, no I did not.  Two cylinders came with fitted pistons ready to use.  This was a materials kit from LMS.  Everything else I had to machine from stock material that was supplied with the kit.
George

[Davyboy]

Hi George.  Just a thought .  Is there any way to increase the temperature difference?  Can you chill the cold end somehow (the fins) ?  If you put the whole thing in the reefer before you fire the burner, the fins will be chilled, if only for a short time, but it may run...  My junk runs alot faster with ice cubes on the cold side, but it may be hard to hold ice on yours.  Good Luck

Davyboy

[Ian S C]

Hi george, with the ball races I salvage from vidio machines,  I don't bother with removing shields, or washing them out, although there is sometimes a ball race in one of the pinch rollers, and it is unshielded.  There's usually 2 X 6 mm bearings in the main motor.  The motor in the photo I put in yesterday has 3 mm bore bearings in the big end, and the main bearings are low profile (very small balls), with a 5 mm bore.  Ian S C

[George_Race]

Hi Ian, and thanks for your comments.
I have a couple of very old video machines here, both a vhs and a beta.  They are really not good for anything nowadays.  Going to dig them out of the pile and see what they have for bearings.

Gosh, maybe I will get to this sooner than I anticipated!  Thanks again for your comments.

Davyboy, I like the idea of cooling the fins!  My grandson, who happens to own the property next to mine, drives for a dry ice company.  I bet a piece of dry ice on the fins would really make the cold end cold!   Gives me another idea to try.  Thanks for the suggestion,
George

[Ian S C]

George, I assume that you have the crank 90* off set,  If so you may find tha by adjusting one of them just a degree or two at a time, first one way then the other, you may find a place where it is happier running.  Would'nt try more than about 10*either way, but see if you can get it running at 90* first.
The above may sound silly, but I sorted A kit one in Christchurch that  had been assembled as a demonstrater, it would not go, they had set the cranks at 180*.  Ian S C