Author Topic: Stirling engine  (Read 11569 times)

Offline Doc

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Stirling engine
« on: February 24, 2018, 02:35:22 AM »
  I started modeling and putting together a Stirling engine design back a long time ago. I used it as training for learning CAD when I became a CAD tooling design engineer. I thought well maybe some day I would build it. Well today is the day I start. It has been a long time in the works. I put a few finishing touches on the model and will start it soon.

Offline Perry

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Re: Stirling engine
« Reply #1 on: February 24, 2018, 06:46:31 AM »
 :popcorn:

Offline Ian S C

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Re: Stirling engine
« Reply #2 on: February 24, 2018, 11:31:11 AM »
Go for it Doc, I'll be watching.
Ian S C

Offline Doc

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Re: Stirling engine
« Reply #3 on: February 24, 2018, 02:32:53 PM »
Got a small start. Cut material and turned up a spud on each end these will be used for aligning the hot cap with it left them oversized until the inside dia is bored. I will locate on the inside bore to turn the fins and at that time I'll finish the end alignment spuds.

PS also the length was cut to finish.

Offline b.lindsey

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Re: Stirling engine
« Reply #4 on: February 24, 2018, 03:56:07 PM »
What diameter is it Doc? Looks large next to the little ones in the background. Happy you have decided to post another build.

Bill

Offline Perry

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Re: Stirling engine
« Reply #5 on: February 24, 2018, 08:04:43 PM »
Hi Doc, what configuration will it be? Do you plan to use some materials like graphite and Teflon?

Offline Brian Rupnow

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Re: Stirling engine
« Reply #6 on: February 25, 2018, 01:04:40 AM »
Jeez Doc--That looks awfully familiar---

Offline Doc

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Re: Stirling engine
« Reply #7 on: February 25, 2018, 01:14:56 AM »
 Pretty much the same principle as the engine you just finished by the way good job Brian!
I had is one modeled up nearly complete for at least 20 years. And now finally going to build it.

Offline Doc

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Re: Stirling engine
« Reply #8 on: February 25, 2018, 01:19:25 AM »
Cooling fins done.


Offline b.lindsey

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Re: Stirling engine
« Reply #9 on: February 25, 2018, 01:30:23 AM »
Cut and polished as well ....that looks great Doc!!

Bill

Offline Doc

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Re: Stirling engine
« Reply #10 on: February 26, 2018, 10:50:15 PM »
Well I have the hot cap rough drilled. I drilled to the depth with a .5 drill then stepped up to a 1.0 drill. Now I need t bore it the rest of the way up to size and flatten the bottom out. I'm making the hot cap from stainless steel.

Offline b.lindsey

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Re: Stirling engine
« Reply #11 on: February 27, 2018, 12:09:05 AM »
S.S. is the way to go I think Doc. Takes the heat, but won't corrode easily if at all.
Bill

Offline yogi

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Re: Stirling engine
« Reply #12 on: February 27, 2018, 12:12:29 AM »
Interesting Doc!
I'm looking forward to see more...  :popcorn:

Offline Ian S C

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Re: Stirling engine
« Reply #13 on: February 27, 2018, 01:02:04 AM »
Doc,I initially thought that having the hot cap thin all over in one carved out of a solid lump of 316 was the way to go, but since then I have decided thatalength of the hot cap about equal to the stroke at the hot end should be left at a little thicker, so .030", the rest about half that to ward the cool end to act as a heat dam, thinner the metal, slower the conduction of heat.  If you make it too thin, the heat tends to cause the hot cap to droop, and wrinkle, mind you thats after years of use at maximum temperature.
Ian S C

Offline Doc

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Re: Stirling engine
« Reply #14 on: March 02, 2018, 01:26:30 AM »
Well I finished up the hot cap unless I decide to add to the end of it. I finished with a wall thickness of .047 and an end thickness of .08




Offline Doc

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Re: Stirling engine
« Reply #15 on: March 03, 2018, 04:20:12 AM »
Ok tube for displacer is turned up ended up with about .03 wall thickness.

Offline b.lindsey

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Re: Stirling engine
« Reply #16 on: March 03, 2018, 12:51:44 PM »
Doc, will you be putting some kind of insulator between the hot cap and the finned part? That will also help a lot with limiting heat transfer to the main part of the engine. Phenolic works well for that if you have any handy.

Bill

Offline Ian S C

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Re: Stirling engine
« Reply #17 on: March 03, 2018, 01:00:01 PM »
I'v never bothered with insulation on any of my motors. This one has an internal thread that screws directly on the end of the cylinder of a BETTA type motor
Ian S C

Offline Doc

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Re: Stirling engine
« Reply #18 on: March 03, 2018, 01:20:15 PM »
   I am planning on using graphite material that I have left over from my stirling fan build. What I am building I would think it would run ok fr short demo's without anything.
    But if I attend any shows (which I'm hoping to do) it would run for extended periods so I will be adding an insulating material. I never gave phenolic  I do have some thinner stuff that turned out to thin for circuit boards that I wanted to build. I may just give that a try. 

Thanks for the comments guys it is appreciated!

PS Ian I like that idea of internal threads
« Last Edit: March 03, 2018, 01:23:17 PM by Doc »

Offline crueby

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Re: Stirling engine
« Reply #19 on: March 10, 2018, 11:18:51 PM »
...
Ever have one f those days you should just not go out to the shop?  :hellno:
...
Oh yes - sometimes I realize it before the next big mistake - not enough times!   :zap:

Offline Admiral_dk

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Re: Stirling engine
« Reply #20 on: March 11, 2018, 02:38:07 PM »
Quote
Ever have one f those days you should just not go out to the shop?  :hellno:

Oh year - I had days where I shouldn't have gone in my own shop and I had days where my employer would have save a lot of money if I hadn't gone to work ....  :wallbang:

Looks like you generally are going in the right direction though  ;)

Offline Doc

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Re: Stirling engine
« Reply #21 on: March 11, 2018, 03:19:58 PM »
Quote
Ever have one f those days you should just not go out to the shop?  :hellno:

Oh year - I had days where I shouldn't have gone in my own shop and I had days where my employer would have save a lot of money if I hadn't gone to work ....  :wallbang:

Looks like you generally are going in the right direction though  ;)


Hahaha I've had days like that too where it cost the company more to have me at work and I should of just stayed home.


Thanks!

Offline Craig DeShong

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Re: Stirling engine
« Reply #22 on: March 11, 2018, 09:55:06 PM »
Quote
Ever have one f those days you should just not go out to the shop?  :hellno:

Oh year - I had days where I shouldn't have gone in my own shop and I had days where my employer would have save a lot of money if I hadn't gone to work ....  :wallbang:

Looks like you generally are going in the right direction though  ;)


Hahaha I've had days like that too where it cost the company more to have me at work and I should of just stayed home.


Thanks!

I assure you- it doesn't just happen in the tool room  :killcomputer: :killcomputer: :killcomputer:
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Doc

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Re: Stirling engine
« Reply #23 on: March 14, 2018, 09:21:35 PM »
Ok haven't done a whole lot the last few days been feeling a little under the weather. But here are some pics I took of where I'm at on it.


Offline b.lindsey

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Re: Stirling engine
« Reply #24 on: March 14, 2018, 10:20:04 PM »
That's looking good Doc. Hope you are feeling better as well.

Bill

Offline Doc

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Re: Stirling engine
« Reply #25 on: March 15, 2018, 01:13:32 AM »
Thanks Bill!

I think its just my nerves getting me down. The closer I get to retirement the more acid re flux  and the worse I feel. Keep think I hope I'm doing the right thing. I have 11 more working day's left after today.

Offline b.lindsey

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Re: Stirling engine
« Reply #26 on: March 15, 2018, 01:35:36 AM »
Congrats Doc...I've got 56 working days left. I am looking forward to more shop time for sure. But I agree, it is a life changing event. Some anxiety is inevitable I suppose.

Bill

Offline Doc

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Re: Stirling engine
« Reply #27 on: March 15, 2018, 02:06:05 AM »
Congrats to you Bill!
Yes I am looking forward to more shop time and in the summer I love gardening and yard work and If I get bored I've been offered a part time job mowing grass at a cemetery just about 1/2 mile from where I live. I've been working at the same place for 43 years so it will be a huge change for me.
  I do hope to be able to attend some of the bigger hobby motor shows.

Offline Jo

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Re: Stirling engine
« Reply #28 on: March 15, 2018, 08:49:25 AM »
I think its just my nerves getting me down. The closer I get to retirement the more acid re flux  and the worse I feel. Keep think I hope I'm doing the right thing. I have 11 more working day's left after today.

Congrats Doc...I've got 56 working days left. I am looking forward to more shop time for sure. But I agree, it is a life changing event. Some anxiety is inevitable I suppose.

Hey just rub it in don't you  >:( Some of us are way back in the cue for retirement :( and we would love to be as close to the front as you guys....

Just imagine every day that hard decision: shall I work on this model  or go play the garden or maybe I could look at starting that model :noidea: When others of us were forced hours before hand to get out of bed and drive to work and are now sitting looking at the forum as it is the only way we can indulge in the look and feel of swarf for most of the day :stickpoke:

Jo
Enjoyment is more important than achievement.

Offline Stuart

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Re: Stirling engine
« Reply #29 on: March 15, 2018, 09:41:16 AM »
Don’t feel bad it 21 years since I retired  :old: :Love:

Yes it was early retirement I was 50 when I gave up w**k  :cartwheel:

I have not regretted it one bit


IMHO it’s the best thing to do  :stir: Jo

Stuart
My aim is for a accurate part with a good finish

Offline Doc

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Re: Stirling engine
« Reply #30 on: March 15, 2018, 08:39:36 PM »
I originally was going to retire 6 years ago and now 6 years later still a little not sure I'm ready mentally. I figure if I'm not ready and want to go back working I'll be able to find something. We shall see.
  Anyway just about to go to a retirement party for one of my friends his last day was today. Go have a couple ales and unwind.
Not gong to get to the shop until tomorrow afternoon.

Offline Doc

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Re: Stirling engine
« Reply #31 on: March 16, 2018, 12:47:15 AM »
OK wasn't at the party long and did get out in the shop and worked on the legs. It's seems a little top heavy right now I'll see after I get the flywheel made and put in place along with power cylinder and see how it feels the. If it still feels a little tipy and top heavy I'll add a couple cross beam under it to widen its stance. So here is what I've got so far.


Offline b.lindsey

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Re: Stirling engine
« Reply #32 on: March 16, 2018, 10:50:03 AM »
What are the white legs made from Doc. I assume a plastic of some sort, but machined or 3D printed?

Bill

Offline scc

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Re: Stirling engine
« Reply #33 on: March 16, 2018, 03:53:12 PM »
Doc, I know 43 years is a long time and retirement will be a huge change, but you have nothing to fear. You are active and have many interests. It's folk who suddenly stop work and then sit in front of the tv / read the paper all day that need to worry. I stopped when I was about 67 and now do three short days per week looking after the boss's collection of "old stuff". It's wonderful :whoohoo:   Get retired and enjoy yourself.

Very Best Wishes.....................Terry

Offline Doc

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Re: Stirling engine
« Reply #34 on: March 16, 2018, 08:44:51 PM »
Thanks Terry!

Bill
  They are made from 1/2 thick Corian. I really like how that stuff machines! I cut the windows in them then buzzed around the perimeter on my NC mill at full depth of cut with a little air to blow the chips away. Looked like a snow storm hit my machine afterwards  :ROFL:.

Offline b.lindsey

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Re: Stirling engine
« Reply #35 on: March 17, 2018, 12:03:07 AM »
Yeah I bet though I have only one experience with it so far. I understand you shouldn't breath it in any more than absolutely necessary though. The kegs look great though.

Bill

Offline Ian S C

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Re: Stirling engine
« Reply #36 on: March 17, 2018, 10:53:53 AM »
Rather than blowing away the dust, a vacuum cleaner set up near the cutting too would perhaps be better.
You might find that you will have to screw the legs on to a base board of some sort, even if that doesn't fall over, it will probably go walkies.
Ian S C
« Last Edit: March 17, 2018, 10:57:47 AM by Ian S C »

Offline Doc

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Re: Stirling engine
« Reply #37 on: March 17, 2018, 01:13:50 PM »
  Thanks Ian !
    I was thinking along that line I am thinking a piece  of corian for a base under the whole thing. Yes I do use a vacuum a lot on the mill trouble is doesn't seem to work very well on small end mills to get the chips out of the way. I need to come up with a smallish nozzle for the vacuum to get it where it will pull the chips a way. The nice thing it really wasn't much dust mostly chips that were along the line of feathers. May have had the feed-rate a little to slow I wasn't sure of the sfpm so I used aluminum feed rate and just increased it a little. I'm not up on feeds and speeds for plastics.
 

Offline Doc

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Re: Stirling engine
« Reply #38 on: March 17, 2018, 06:55:59 PM »
Ok did a little this morning made the power cylinder mounting flange.
Cut it n the nc machine mounted cylinder temp with a couple of the screws.



Offline Doc

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Re: Stirling engine
« Reply #39 on: March 17, 2018, 11:36:04 PM »
Was really nice outside this afternoon ended up taking Rowdy "my boxer" for a long walk so didn't get a whole lot done this afternoon king of like this morning. But I did get the bearing mount blocks "pillow blocks". So I am making headway on it just not to fast.


Offline b.lindsey

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Re: Stirling engine
« Reply #40 on: March 24, 2018, 06:32:33 PM »
Doc, it seems you have to be a member of that forum to view the .pdf.

Bill

Offline Doc

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Re: Stirling engine
« Reply #41 on: March 24, 2018, 09:21:47 PM »
Hmmm guess I didn't realize that couldn't load it here it is just over 4mb and one file here cannot be over 1mb. I probably should remove it then.

Offline Admiral_dk

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Re: Stirling engine
« Reply #42 on: March 26, 2018, 08:50:19 PM »
Looks like you aren't far from first pop  :ThumbsUp:

Offline zeeprogrammer

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Re: Stirling engine
« Reply #43 on: April 08, 2018, 12:16:08 AM »
Congrats on retirement Doc.
Sorry you were/got sick.
If it helps any...the 2nd to the last day of my work...I was passing a gallstone. Luckily that was a Thursday and we were off on Friday.
Had the weekend to recover before I retired on Monday.

(I don't have a gall bladder...but I have a stricture in a bile duct that, once in a while, gets plugged. Think the Alien movie.)

So keep at it! Enjoy! Most people don't have a hobby or anything to do. You have a shop. Enjoy!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Doc

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Re: Stirling engine
« Reply #44 on: April 08, 2018, 02:36:01 AM »
Thanks Carl!

Oh man that would suck stones are not fun!

Offline Sleddog

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Re: Stirling engine
« Reply #45 on: April 08, 2018, 06:08:37 PM »
Congratulations on the retirement Doc. I’ve been battling a monster head cold for the last week too. Tried to work in the shop yesterday but spent more time blowing my nose & wiping my eyes.
Hopefully it’ll be better by the time we head to NAMES next week.
You should give yourself a retirement gift & go too.

Sleddog

Offline Doc

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Re: Stirling engine
« Reply #46 on: April 08, 2018, 09:24:47 PM »
Thanks Sleddog!
 
Not going to make it this year to much going on with the in-laws mother and father-in -law still live at home They are in their 90'S and he just fell and cracked 3 ribs she has asthma and is on oxygen so we need to stick around and help out. I do hope to eventually make it there. Righ now the shows I attend are the one in Rollag MN and then the one Rocford ND.

Offline Admiral_dk

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Re: Stirling engine
« Reply #47 on: April 15, 2018, 05:57:57 PM »
Congratulations, you have a runner Doc  :ThumbsUp:

Offline b.lindsey

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Re: Stirling engine
« Reply #48 on: April 15, 2018, 06:42:09 PM »
Very nice Doc. Seems to be running very smoothly.

Bill

Offline Doc

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Re: Stirling engine
« Reply #49 on: April 15, 2018, 11:03:18 PM »
Thanks Admiral_dk

Thanks Bill she runs ok was still looking for the clicking sound haven't found it.

 

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