# Rudy Kouhoupt's Stirling



## Damau (Sep 6, 2012)

http://s1245.photobucket.com/albums/gg593/DaleMauney/Model Engines/?action=view&current=Stirling.jpg


I completed this engine in 2007 and never could get it to run like it is supposed to.  It would run about 5 or 6 revolutions and stop and even that required a lot of heat from a propane torch.  I finally got tired of messing with it and gave up on it and decided it would probably never run.

Recently I read a couple of threads on this forum where members were having problems getting theirs to run.  They took the advice of several members' suggestions were successful in making improvements and finally getting theirs' to run.

Now that I was armed with some suggestions from the threads I had read, my interest perked and I went to work on mine.  I checked to see if I had any air leaks and sure enough, I did have a minor leak that needed to be sealed.

I disassembled the displacer, made new gaskets, and reassembled using RTV silicon sealant.  I also checked the timing of the displacer and the power piston and found that to be a degree or two off the necessary 90 degrees.

These little tweeks proved to be worthwhile and the little engine would now run.  This being my first engine build, I almost wet my pants with all the excitement of seeing it live.

It still was not right and I knew it was requiring too much heat.  Heat would be conducted throughout the engine, even the flywheel would get hot.

I continued tweeking and trying to reduce friction and it seemed to get better each time.  I was on the late, Jerry E. Howell's website and found a tip that improved my little engine more than anything I have tried.  Thanks to Jerry's family for keeping his site online.

The tip I am referring to is, making a "waist" area between the hot cap and the cold end of the displacer.  THIS REALLY WORKS!!!!!!

Here is a link to Jerry's website where he talks about heat conductivity:  Pay close attention to the 3rd. and 4th. paragraphs.  That is where he talks about heat conductivity.

http://www.model-engine-plans.com/engineeringtips/heatabsorbers.htm

After reading that, I decided to turn a "waist", not waste, on the hot cap of my engine.  Per Rudy Kouhoupt, my hot cap is made of copper tubing.  I knew turning soft copper would be a challenge and it was.  I made cuts of .001 to .002 with a very slow feed rate until I got the displacer wall about as thin as I felt comfortable with.

I stopped turning the "waist" when the displacer walls were about .020 thick.  I thought that would be thin enough for soft copper.

Below is a picture of my hot cap after I turned the "waist":

http://s1245.photobucket.com/albums/gg593/DaleMauney/Model Engines/?action=view&current=IMAG0210.jpg

Jerry Howell was right!!! The less metal, the less heat it will conduct.  Even though I did not go as thin as Jerry said he had done, it did make a big improvement on my little Stirling.

Here is a video of it running on a propane flame after about 15 seconds of warm up:

http://s1245.photobucket.com/albums...ine Videos/?action=view&current=VIDEO0028.mp4

Stirling engines must be like wine, they get better with age.  Here is a short video of it running from the heat of a little alcohol burner I made from some scrap 6061.  The fuel is denatured alcohol.

http://s1245.photobucket.com/albums...ine Videos/?action=view&current=VIDEO0029.mp4

I hope that my efforts with this post will help someone else.  Thanks go to the members that posted suggestions in the previous threads about this engine and to the late, Jerry E. Howell.

Your comments are welcomed.


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## rhitee93 (Sep 6, 2012)

Congrats and thanks for the post Dale.  I am currently working on my first stirling engine.  I am a long way away form troubleshooting, but that day will arrive soon.  I'll keep your experience in mind as I go


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## rleete (Sep 6, 2012)

Very nicely done.  I really like the stirlings because it almost seems like magic that they run at all.

Congrats on persevering and getting it to run.


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## rleete (Sep 6, 2012)

Double post!


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## Davyboy (Sep 6, 2012)

Dale, It sure is a thrill to see the engines run, after all the work is done.  Stirlings are one of my favorites.  I looked at your album on P-Bucket, the brass engine looks interesting too.  How about some more info on that one?  Thanks for sharing.

Davyboy


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## idahoan (Sep 6, 2012)

Hi Dale

Great job getting your Stirling engine running; If you want to take it a step further ditch the copper hot cap and make one from stainless or mild steel. Brass and copper accel at moving the heat from the hot to the cold end of the engine. I'm not sure why some designers call out an all copper for a hot cap I guess they just didn't know any better

When my buddy built his Denney Improved engine the plans called out an  all copper hot end (bad idea). It transferred so much heat into the cold  end that it wouldn't run well. It was hard to keep the water cool and a  huge flame was required just to keep it running. 

When he built his Rider Ericsson last winter he made a steel hot end  with a thin copper hot cap silver soldered on; what a difference that made. He also  turned a waist near the top (ala Jerry Howell) to help stop the heat  migration from the hot end to the cold end.

After the Rider was finished he went back and made a new hot end for the  Denney and now it runs just as well or maybe better than the Rider. 

Thanks for sharing,
Dave


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## IronHorse (Sep 6, 2012)

Great job on getting your engine to run, I know these engines can sometines be hard to keep running. I had a problem with my Alpha engine, and only got it to run after putting it on the shelf for a few months while I thought of ways to fix it. A few tweeks later, I had a runner

You can see the thread here: http://www.homemodelenginemachinist.com/f31/alphavictory-engine-build-8343/


IronHorse


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## Damau (Sep 7, 2012)

Thanks to all the views and comments.  Comments always make all our efforts seem worthwhile.

Davyboy, I have 2 other videos on Photobucket of steam engines so I am not sure which one you inquired about.  I bet it is the Liney RV-1, 2 cylinder with the flywheel in the center.

I am not affiliated with either of the websites I will list below, just a customer.  The links are listed only to help others.

The plans for the RV-1 and other engines can be found on:

http://www.lineymachine.com/

The other steam engine is another of Rudy Kouhoupt's designs.  I got the plans for it from SmartFlix.  They rent DVD's on a lot of technologies including 3 or more of Rudy's engines.  I just received another of Rudy's videos on pin striping.  I think all of Rudy's engine DVD's include a set of drawings.

The URL for SmartFlix is:

http://smartflix.com/

Once on the site, look to the left and scroll down to Metalworking and open it.  
There are a lot of "how to" DVD's you can rent.

I hope this helps.


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## MarioM (Sep 7, 2012)

Hi Dale, your engine looks great and runs nice.  Good work.  I made the very same engine a few months ago and got it running with the help of this forum.  It was my first engine and also had to go to bed frustrated for a few days with the same problems you had.  It is definitely a great success to got it running.
I also found that after it run, started to get better and better and using less heat.....it seems like they break-in and run better.

Mario


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## Davyboy (Sep 8, 2012)

Thanks, Dale for the info on the Liney and smartflix sites.  There's a lot of neat stuff there.

Davyboy


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## Damau (Sep 8, 2012)

I agree Davyboy, I have learned a lot from the DVD's I have rented from SmartFlix.

The little Liney RV-1 was a joy to build and it runs good.  I prefer my engines to run at low RPM's. (More about that in the next paragraph) The plans call for the flywheel to be made from 6061 aluminum but I used 360 brass.

To explain my wanting my steam engines to run at low RPM's.  When I was in high school in the early 50's, our school's athletic field was across the railroad tracks from a lumber company that used a steam engine to power the millwork machines.  As we took PE, we could hear the old steam engine cranking away at 200 RPM's or so. (Okay, I just revealed my age but let me say here, I feel blessed to be above ground).

I could go on and on here and talk about the steam locomotives that worked in that area but I will save that for another time, another forum.  I am not going to say anything about our putting pennies on the track for the Consolidation locomotive to mash into the size of a quarter.  Like Forrest Gump said, "thats all I am going to say about that".

A bit of levity goes a long way and I love it.


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