Author Topic: Lehmann Stirling Engine  (Read 4981 times)

Offline yogi

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Re: Lehmann Stirling Engine
« Reply #15 on: December 21, 2018, 11:17:12 PM »
Thanks guys!  :cheers:

Achim, that or maybe power the shop...  :Lol:

Tim, thank for posting the video. That an exquisite model. Here another video of a beautifully completed engine:



Yogi

Offline toolznthings

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Re: Lehmann Stirling Engine
« Reply #16 on: December 22, 2018, 01:41:25 AM »
Busy  :cartwheel:  :ThumbsUp: :ThumbsUp:

Nice project !
Thanks for the visit !
Brian

Offline PJPickard

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Re: Lehmann Stirling Engine
« Reply #17 on: December 22, 2018, 02:27:25 AM »
If you search youtube for "Lehmann Stirling engine" you will find a bunch of nice models. The Lehmann is one of my favorite hot air engines. I look forward to seeing this model develop!

Offline steamer

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Re: Lehmann Stirling Engine
« Reply #18 on: December 22, 2018, 02:30:01 AM »
Nice looking project Yogi,   Propane fired?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline ShopShoe

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Re: Lehmann Stirling Engine
« Reply #19 on: December 22, 2018, 01:34:08 PM »
That is a very interesting Engine.

It is pleasing to watch and I am impressed with how quietly it runs.

Thank You for posting.

ShopShoe

Offline bent

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Re: Lehmann Stirling Engine
« Reply #20 on: January 02, 2019, 08:58:57 PM »
Very cool looking engine, and a nice size.  Wondering what the purpose of the flyball governor is and what it adjusts (if anything) to regulate speed?

Offline yogi

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Re: Lehmann Stirling Engine
« Reply #21 on: January 03, 2019, 03:09:17 PM »
Thank you guys for the kind comments! It's very much appreciated.  :cheers:

Dave, yes, the plan is to have it propane fired.

Bent, the governor will open a valve into the displacer cylinder and relieve air pressure from the engine, regulating the speed.


Yogi
 

Offline Craig DeShong

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Re: Lehmann Stirling Engine
« Reply #22 on: January 07, 2019, 09:57:28 PM »
I've sidelined a few projects over the years myself, then returned to them and thought, "Why did I ever put this aside, it's pretty far along and it's going to be really nice to finish it".

I'm thinking this is one of those projects too.  I'll be following along.  :popcorn: :popcorn:
Craig

Offline yogi

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Re: Lehmann Stirling Engine
« Reply #23 on: January 09, 2019, 12:31:30 AM »
Craig, thanks for checking in and yes, it's definitely good to be working on this project again...

To continue, I'll be making the cylinder. I made it out of 1144, and has a 50mm ID, 62mm OD, and is 194mm long when finished.
The challenge on this part, is for the tool not to chatter in the long bore. To rough out the bore, I used a carbide insert boring bar and roughed it out from either side. To finish, I used a HSS boring bar, to be able to take light cuts, and was able to accomplish it without chatter.

Taking a finishing cut, using a 1" boring bar with a HSS bit. The stick out on the bar is 8 inches.




The surface finish from turning alone was really nice already, as shown in the picture below. To make it even better, I used a small break cylinder hone. This took only a few passes to finish.




The cylinder is installed in the cylinder housing with Loctite 609.




The honed cylinder, even though the surface finish isn't showing up well in the picture (in reality it's better than it looks).





Thanks everyone for following along, and stay tuned for more.
Yogi


Online b.lindsey

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Re: Lehmann Stirling Engine
« Reply #24 on: January 09, 2019, 01:46:32 AM »
Very nice finish on the cylinder. Still watching along even if quietly Yogi.

Bill

Offline yogi

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Re: Lehmann Stirling Engine
« Reply #25 on: March 07, 2019, 07:31:24 PM »
Thanks for following along Bill!  :cheers:


The next parts for the engine are the bearing blocks.

For the tall bearing block, I used hot rolled bar, and milled the profile to full depth on the first op.






Moving on to the second side by milling away the remaining stock and finish to final thickness:




The top is tapped for the mounting of the cap.




The bottom mounting holes are drilled:




Counter bore from the top for the mounting pads. To be able to reach, I used a DA200 collet extension.






The short bearing block was already made, all it needed to be finished, was a small slot as a cosmetic feature.




The bearing caps are installed, and bored out for the bearing.








The caps are then finished up by tapping a hole to mount the oil cups.




And the last part was to drill a hole in the blocks for a pin to prevent the bearing to rotate.






The finished bearing blocks:







Thanks everyone for following along, and stay tuned for more.
Yogi




Offline cnr6400

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Re: Lehmann Stirling Engine
« Reply #26 on: March 07, 2019, 07:50:30 PM »
Looks great Yogi, well done! :ThumbsUp: :ThumbsUp: :ThumbsUp:

Offline Ye-Ole Steam Dude

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Re: Lehmann Stirling Engine
« Reply #27 on: March 07, 2019, 08:59:27 PM »
Hello Yogi,

Beautiful workmanship.

Have a great day,
Thomas

Online b.lindsey

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Re: Lehmann Stirling Engine
« Reply #28 on: March 07, 2019, 09:15:42 PM »
A unique but very pleasing shape to the bearing blocks Yogi, especially the caps. Looks  very nice.

Bill
« Last Edit: March 07, 2019, 11:00:47 PM by b.lindsey »

Offline Dave Otto

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Re: Lehmann Stirling Engine
« Reply #29 on: March 07, 2019, 09:55:55 PM »
Nice looking parts Yogi!

Dave