Stirling Engine from Norm Jones drawings

Discussion in 'Finished Projects' started by BobsModels, May 27, 2018.

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  1. May 27, 2018 #1

    BobsModels

    BobsModels

    BobsModels

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    Hi

    In 2014 my two granddaughters wanted to build a Stirling engine after several other projects. Model Engine builder had an article by Norm Jones and picked that one. They started in the shop when they were 8 and 10, now 19 and 21.

    The oldest one, Rachel, finished up her engine this week, spent 6 days making parts and fitting it up. She is a senior this fall in Chemical Engineering at Michican Tech in Houghton MI. Being in college she had limited time but would try and visit for a few days each year. When they were younger they would spend almost a month. They are excellent quilters and spend time in grandma's shop also.

    Rachel put a fire to the engine Saturday morning around 11 am and flipped it over and it took off. The smile and expression on her face was unbelievable. I think all model builders feel the same way when an engine comes alive for the first time, but it is great to see that on a young person interested in the hobby.

    Natalie almost had hers done last summer. She had the graphite piston to make and some polishing. She will need to fit the engine up and see how smooth everything is. She also is in college targeting a MD degree. This summer she is taking a class and working to pay for college. Her goal is to get out to grandpa's shop for a building session, if she can find two or three days in a row. Its a 2 hour drive out to my place.

    Here is a link to Rachel's engine:

    https://youtu.be/TYlPWvfav4o

    Bob
     
  2. Dec 4, 2018 #2

    terryp

    terryp

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    Hello Bob, I congratulate your grand daughter on her Sterling, outstanding and a beautiful job. I have always wanted to do a Sterling and that engine looks like a great place to start. Is there a way I can get the drawings? Thanks! Terry from Texas.
     
  3. Dec 4, 2018 #3

    BobsModels

    BobsModels

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    Terry

    I will pass your compliment along to her.

    The drawings are from an article in Model Engine Builder Magazine Issue 22. There is a picture of his on the home page and you should be able to get a copy here:

    https://www.modelenginebuilder.com/

    Good Luck on your build

    Bob
     
  4. Dec 4, 2018 #4

    terryp

    terryp

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    Bob, I will contact Model Engine Builder to see if back issues are available. Thanks for the tip and prompt reply.
     
  5. Dec 21, 2018 #5

    Rolland

    Rolland

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    I have completed building the engine but am having trouble getting it to run, I would appreciate any assistance you can give, I think the timing may be off but not sure. It is built to the exact dimension listed on the drawings and it turns over freely. and the timing is the 90 degrees as the directions indicate.
     
  6. Dec 22, 2018 #6

    BobsModels

    BobsModels

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    Hi

    I did not build it. Rachel got it running. She will be visiting at Christmas for a few days. I remember that one real tricky thing was getting the power piston end clearance correct. She had do move the relative distance of the crank axis to the top of the cylinder. The space between the top of the piston and the top of the cylinder was critical. I remember her needing to elongate the holes she had drilled to allow enough movement of the transfer block so she could get the correct clearance. I think it was a real small dimension, and I think it was in the article not in the prints.

    Set your piston at top dead center and post picture's of both sides of the engines . I can compare that to hers. I do not have it available right now.

    Do you get any bounce?

    The displacer piston had a similar critical clearance issue.

    Not being a stirling engine expert I think the smaller the engine the more critical the volume of air becomes and therefore the clearances become important.

    Bob
     
  7. Dec 23, 2018 #7

    Rolland

    Rolland

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    cAzxyQGj_o[1].jpg VC8684iE_o[1].jpg Bob
    Here are the two photos. The displacer pin is at 12:00 and the power piston is at 9:00 as viewed from the displacer piston side. I think that is what the article said, bu correct me if I am wrong.
     
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  8. Dec 24, 2018 #8

    BobsModels

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    Rolland

    That is exactly as hers is timed. Do you have any bounce? Hers will spin freely if I flip the flywheel . If I do it softly there is a clear bounce back. the flywheel reverses on the last spin. Again I am not an expert on these engines. If you have the slightest air leak it will not work. I build the Rider Erickson 1/4 scale. I put a valve on the air chamber like the original. What is allows me to do when demonstrating is to show that the air needs to be captive. All I have to do is open it slightly and the engine stops instantly. I am not sure what else to tell you. Rachel will be here at Christmas for a couple of days I will let her read your posts.

    Could you post a video on U Tube of what it does? I know when she starts it she fans the flame over the whole hot tube end, then keeps the flame at the very end of the hot tube ie the copper end.

    Bob
     
  9. Dec 24, 2018 #9

    Rolland

    Rolland

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    I found the problem, ya have to read all the instructions, I used low temp silver solder instead of silver braze so its back to the lathe to make the proper cylinder.
     
  10. Dec 25, 2018 #10

    BobsModels

    BobsModels

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    Rolland
    Glad you found it. What cylinder has the issue? The granddaughters decided not to silver braze the flanges. They made the cylinders from solid stainless round stock. The only silver brazing was the copper disk on the displacer cylinder.

    The younger one spent about 10 hours on the displacer cylinder and the last boring cut she missread the dial and destroyed the part. Next day it only took her 4 hours to re do it.

    Merry Christmas and Happy New Year

    Bob
     

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