Author Topic: Flywheel patterns  (Read 5265 times)

PatJ

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Flywheel patterns
« on: November 28, 2013, 12:59:49 AM »
I ran across some guys who are using 3D models that can be downloaded from Grabcad to make CNC patterns for steam engines.

I downloaded the files just to see if I could get at the models, and sure enough, you can download the models and open each one, or the entire assembly.

The flywheel just did not look right to me, so I took ten minutes to open the sketch, tweek it, and modify the part.

Grabcad is the brown flywheel, my tweek is in gray.

Which one do you prefer?

Offline chucketn

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Re: Flywheel patterns
« Reply #1 on: November 28, 2013, 01:26:42 AM »
Looks good, Pat. Can you scale the size up and down? I need an Ericsson flywheel at 3 1/2" in dia.

Chuck

Offline b.lindsey

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Re: Flywheel patterns
« Reply #2 on: November 28, 2013, 01:34:43 AM »
Chuck, are you making a 1/8 scale version and if so will the rest of it be cast or bar stick?

Bill

Offline chucketn

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Re: Flywheel patterns
« Reply #3 on: November 28, 2013, 01:45:10 AM »
Bill, I'm just completing my foundry and will try to cast the major parts of the Rider-Ericsson. And, yes, it will be 1/8 scale.
At the moment, the cold weather has me shut down, so I'm trying to make patterns. Also working on the '47 PS Vertical Woodson.
Chuck

PatJ

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Re: Flywheel patterns
« Reply #4 on: November 28, 2013, 02:30:55 AM »
Yes, I can scale it to any size, but be careful as those spokes will be a little thin at that scale, you may want them slightly thicker.

I assume you want a factor of about 1.02 for shrinkage of aluminum?


PatJ

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Re: Flywheel patterns
« Reply #5 on: November 28, 2013, 02:57:40 AM »
Are you looking for a 2D drawing like this?

This is at 1.02, which will shrink to approximately 3.5" dia. after casting in AL.

And don't forget to make the rim and hub slightly thicker to give machining allowances there.

And add a boss at one side of the hub if you want to try and grip it there for some initial light cleanup.

You will probably need to crown the rim so you can pull the pattern(s).
For 3.5" size, I guess I would go with a one piece pattern, and use a draft angle on the outer surface of the rim that is across the entire surface (not crowned).

Good luck.

Offline chucketn

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Re: Flywheel patterns
« Reply #6 on: November 28, 2013, 12:49:09 PM »
Thanks, Pat. File saved. I will work on a pattern this weekend.

Chuck

Offline Jasonb

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Re: Flywheel patterns
« Reply #7 on: November 28, 2013, 01:12:11 PM »
Pat maybe you have a different eye to me but to my eye the first two grab cad images look far more like an original flywheel, the later two are too curved and much too large a fillet where the spokes meet the rim and just look like a 6 spoke version of the green twin flywheel.

This is more the shape



Chuck, there was a series in ME a couple of years back of a RE engine that maust be about the scale you are thinking as the flywheel was that sort of size, i've seen it running in the flesh and it goes well.

J

PatJ

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Re: Flywheel patterns
« Reply #8 on: November 28, 2013, 04:23:06 PM »
Thanks for the info Jason.

I must admit, I am totally ignorant of the Ericsson engine other than having seen them around the shows, and the free-lance model that my dad built.  I have seen a number of variations in models too.

I will have to research this engine a bit to get a feel for what it originally looked like.

My stylized version is rather distorted to give is a little more sweep and flow (whatever that means).
But I also kept the grabcad version in the PDF file so he could choose which style he liked, or like you mention, which style was like an Ericsson.

These engines are fascinating to watch, and the ones I have seen are very quiet without the chuff or pop of exhaust from other type engines.

Offline Jasonb

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Re: Flywheel patterns
« Reply #9 on: November 28, 2013, 04:59:44 PM »
More for Chuck, this is the one that was in ME with a 3" flywheel and the original its based on which is a domestic pumping engine so one of their smaller designs.


Offline chucketn

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Re: Flywheel patterns
« Reply #10 on: November 28, 2013, 05:35:35 PM »
Thanks, Jason. I wish I had access to ME to read that article. Has it been published anywhere else that would still be available?

Chuck

PatJ

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Re: Flywheel patterns
« Reply #11 on: November 28, 2013, 06:24:49 PM »
This is my dad's free-lance version.

Offline chucketn

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Re: Flywheel patterns
« Reply #12 on: November 28, 2013, 07:16:07 PM »
Very nice, Pat. Thanks for showing us that.

Chuck