Learnin' Stirlin' - a peculiar looking Stirling Engine

[Sanjay F]

So far on my Model Engineering journey I have built and restored steam engines, had a bit of a disaster with an IC Engine and built a flame gulper but have always fancied a Stirling project.

I've read up on Stirling engines and understand the basic principles and have a major project on the shelf for another time when this very odd looking (some would say ugly) engine came up very cheaply; what swung it for me was its homemade agricultural looks, the fact the radiator looks like a hip flask with a cooling fan and it needs some TLC 

I bought the little burner from AliExpress for the princely sum of £1.99 and probably the same for the meths to burn in it. I filled the radiator with water, sparked up the burner and after a while and a lot of smoking smelliness I actually got some movement out of it, however, water started leaking from a few places and the whole thing is tight and needs a good clean to make it run smoother and faster. The burner and the hot water made a nice marks on the woodwork so I question if if should be mounted on wood?

I'm going to dismantle it, clean it up, put the same size bolts in rather than the current random ones (maybe), stop the leaks and find a belt to run the fan; this is only a learning exercise after all.

Finally, I'm going to recycle the old Vulcan beam engine base from my previous build and mount this strange looking object on it...........I think it will look better (questionable) and at least the base will get a new lease of life!

[Dave Otto]

Wow! Something only a mother could love, or maybe it's creator.
Good luck with the restoration.

Dave

[Jasonb]

Possibly a Robinson, but I don't think Heath is the one we usually associate with hot air engines

[crueby]

Neat old engine - don't think I've ever seen a sterling with a radiator and a fan like that. At that size, did it come out of a Reliant Robin?!   

[Sanjay F]

I thought there would be various reactions to this one; it's certainly 'different' 

[Sanjay F]

I have dismantled and done some cleaning and we now have some freer movement, you can see the displacer and piston lifing there's compression and now the flywheel is hooked back up it kind of spins

I guess it should be okay to fire the thing up without the rad as a lot of engines don't have them? Mind you they do have cooling fins which this doesn't, I don't want to damage it? 

https://www.youtube.com/shorts/jN3p3jbKFCg

https://www.youtube.com/shorts/CVNRMRge0lA

[crueby]

For short runs its fine. The trick to keeping a sterling running is the temperature differential, so without the radiator the differential will go away after a little running and it will lose pressure changes and stop.

[Jasonb]

I run my water cooled ones dry and they go for quite a while, you can always blow a bit of compressed air at it.

The bounce as you turn it over is the way you want it.

Now just don't get too excited when it runs and knock the meths burner over. You have a record

[Dave Otto]

 Looks a little bouncy, that is a good sign. Just don't get too carried away with the heat, I have seen a number of them damaged by guys getting carried away with a torch trying to get an engine to run that had issues.

Dave

[Zephyrin]

some signs of compression inside, a good point although the movement seems somewhat stiff when turning the engine by hand...may be too much oil at many places.
She could make a quite decent model after the repair and cleaning you usually do on all your models!

[Sanjay F]

This is what it does without cooling, but water in the jacket. I think it wants to go, I may try the compressed air on it and see what happens.

The water leaks are caused by several problems at the joints on the pipework (unsurprisingly). The pipe from the water jacket just pulled out and wasn't fixed but must have been originally soldered in place (red arrow) and I managed to break the other joint while undoing it (blue arrows), but can I can make a longer 5/16" x 32 hex piece which will screw 2 sections together.

My mate who's a plumber has just told me about liquid PTFE which sounds like just the job for sealing the joints.

And yes, precaution with inflammable materials has been noted, the wife is already looking at me dubiously and upping my life insurance 

https://www.youtube.com/shorts/2sJuxvNxfG8

[Dave Otto]

The water going into the displacer rod bushing is not helping anything.
Have you checked the timing? The displacer piston needs to lead the power piston by 90 degrees. The engine will only run in one direction unless you change the timing.

Dave

[Sanjay F]

No, not touched the timing so its as it came, I'll take a look at that and it felt like it would only turn in one direction. I guessed the water at the top wouldn't help 

[Sanjay F]

Experiment II

I installed some temporary pipework to get some cooling and covered the rad with an ice cold cloth. The displacer and piston are definitley 90 degs apart, but I think the issue is what Dave pointed out before, there seems to be water coming up through the where the displacer rod is, no matter how much I dry it up more comes up.

I presume this should not be the case and the water jacket/displacer cylinder has a leak or there is water in the displacer cylinder which needs removal?

If that is the case then whole thing needs taking apart and finding out where the issue is and resealing; I can see lots of sealant everywhere!

If a complete tear down is required it may be the end of this adventure for now as I want to get back to my Hicks Oscillator; any thoughts about the water around the displacer rod gratrefully received 

https://www.youtube.com/shorts/FdCg_a9JizM

[Dave Otto]

I didn't realize that the water was being forced up from the inside of the displacer cylinder, that make it even worse. I thought that it had just leaked out of the cooling from the outside.
So for sure sure it seems that there is a leak path inside the cylinder that is going to need repairs. At this point I don't think you have any other choice but to tear it down and investigate the source of the water. Also the water being pushed up through the displacer rod bushing like that would indicate a less than desirable fit on bushing /rod.

Dave