PRR S2 turbine in hernia scale?

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PRR5406
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Re: PRR S2 turbine in hernia scale?

Post by PRR5406 »

Beautiful model of the S2! I have to wonder if it is truly steam powered of electrically motored.
I love it!
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FKreider
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Re: PRR S2 turbine in hernia scale?

Post by FKreider »

PRR5406 wrote: Mon Jan 16, 2023 11:53 am Beautiful model of the S2! I have to wonder if it is truly steam powered of electrically motored.
I love it!
It is steam powered with a copper pot like any proper 3/4" live steam loco.
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PRR5406
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Re: PRR S2 turbine in hernia scale?

Post by PRR5406 »

I am not a Gauge 1 operator, but you locomotive has won my heart. Where can I see it run? Anything on Youtube yet?
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LVRR2095
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Re: PRR S2 turbine in hernia scale?

Post by LVRR2095 »

Dick, that isn’t gauge one…it is 3 - 1/2” gauge.
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Bill Shields
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Re: PRR S2 turbine in hernia scale?

Post by Bill Shields »

very cool...and pictures of the finished boiler and / or the tube layout?
Too many things going on to bother listing them.
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PRR5406
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Re: PRR S2 turbine in hernia scale?

Post by PRR5406 »

Keith, I'm very much more in love with the model S2 in that case!
Like Bill, I want to see the innards of the drive system. If it can be done with 3 1/2", why not 1/8th?
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Bill Shields
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Re: PRR S2 turbine in hernia scale?

Post by Bill Shields »

It has never been a question of 'can it be done' -> but a question from an engineering standpoint (of thermodynamics) -> will it be workable as a loco?

Heck...just getting it to this point is more than I would bite off to chew....
Too many things going on to bother listing them.
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Re: PRR S2 turbine in hernia scale?

Post by apm »

My understanding is that small steam turbines always had problems with efficiency due to losses in clearances such as at the tips etc that don't scale well.

I would think that in 3/4 scale with the tools most hobbyists have available this would be an even bigger issue. Perhaps with websites like shapeways and 3D printing maybe it'd be a little easier today than ever before, however I would still think getting power out of a little turbine would probably be difficult to say the least.

However I think the better option if one wanted to compromise a little bit prototypically on the internals would be to use a vane type motor similar to what exists in the back of a die grinder. I think this would be a lot easier to make than a turbine and probably output a lot more power with a lot less loss. From the outside I doubt anybody would know the difference. I would think doing this would be practical in almost any scale. I wonder what was used in the model shown above? Did the builder go the prototypical route or the much more practical route?

Only issue I think I would see with a vane motor is that you are pretty much stuck with the expansion that you set up to begin with. There's no equivalent to adjusting the cutoff on your reversing lever you are going to be stuck with the geometry you choose. Typically in a vane motor I think it has to do with how eccentric your shaft is to the main board chamber however I've never really studied them so maybe I'm wrong?

Years back I had given some thought about making h
a turbo generator and figured the vane motor would be the way to go. Then I made my locomotive look a little older and went with an oil lamp and that was the end of that. Nonetheless has anybody ever done this in live steam if only for a generator? I don't see why it wouldn't work.
FKreider
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Re: PRR S2 turbine in hernia scale?

Post by FKreider »

I am simply cross posting pictures from the facebook group where Chuck's son Jim has posted updates so I do not have details of the engine, anyone who wants to know more would have to get in contact with Jim or Chuck.

Chuck is truly a master craftsman, he does all of his own pattern work and castings including iron with his home foundry setup:
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The turbine appears to be multiple stages with several rotors which then drives the gearbox:
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Keep in mind that this is all in 3/4" scale!
Last edited by FKreider on Sat Jan 21, 2023 8:27 am, edited 1 time in total.
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Re: PRR S2 turbine in hernia scale?

Post by FKreider »

Here is a shot of the front tubesheet under construction which shows the tube configuration along with the superheater which had already been constructed at this stage. The superheater design is quite elegant/simple.
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PRR5406
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Re: PRR S2 turbine in hernia scale?

Post by PRR5406 »

I want to see it running! This is incredible.
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Steamer Al
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Re: PRR S2 turbine in hernia scale?

Post by Steamer Al »

The stuff this hobby keeps turning up never ceases to amaze me. One reason I love it so much. I hope they post some videos when its running!
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