Regulator size

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djjh87
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Re: Regulator size

Post by djjh87 »

Hi Paul congratulations on this impressive build of your challenger and your k36. Send us more build pictures as you go. Jim
No problems just solutions.
k36no4862002
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Location: Surrey, UK

Re: Regulator size

Post by k36no4862002 »

Hi Bill,
Not sure I would even know how to calculate the steam generation, is there a guide I can look at ?
Paul Edmonds,
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
James Powell
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Re: Regulator size

Post by James Powell »

Paul, how many pounds per hour of fuel are you going to burn ? Or how big is the grate (if coal fired). Multiply that by 10, and that's a rough (but good enough for this) answer.

So, if you have 2 sq ft of grate (288"), you likely can burn not more than 100 lb/hr, and generate ~1000 lb hr of steam.
(note that a Standard Sentinel waggon is rated at about that...and 40 HP !)

Or if the oil burner you are fitting is 2 gal/hr, then 2*8=16 lb/hr, 160 Lb/H of steam.

(if you thinK Metric, use the appropriate conversions- 2.2 lb=1 kg, I'd use 4 L/Gal, again, these are close enough #s)

Those are really rough, but for the context of steam velocities, probably accurate enough numbers. I assume a Engineer has done math on the boiler, so that should have (*) been one of the calculations done. There is another way to do so, KN Harris outlines it in Model Boilers & Boilermaking, of using the heating surface & calculating based on heating surface rather than grate area. I think the results are likely within the bounds of errors especially on large models...(or small full sized engines...)

My sticky notes math seemed to indicate a velocity of around 32 km/h through the throttle valve full open full flow, but that's based on a bunch of assumptions...(as in, it's more like a Scientific Wild Guess than accurate). However, it likely is good enough to suggest that you are in the correct ballpark.
765nkp
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Re: Regulator size

Post by 765nkp »

Your Challenger is very impressive, thanks for posting the pictures. Look forward to seeing more.
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Bill Shields
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Re: Regulator size

Post by Bill Shields »

So ..working backwards, at full running speed, how much steam will be required at half and full boiler pressure?

Know PLAN?
Too many things going on to bother listing them.
RThomp
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Re: Regulator size

Post by RThomp »

Both locomotives are really neat. Is the 4-6-6-4 from Roger's design ?
KarlKobel
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Re: Regulator size

Post by KarlKobel »

The Challenger looks great.
The photo reminds me, as soon as I got the rolling chassis complete, I hauled it around the railroad to see how it behaved over 'normal' track.



Karl
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k36no4862002
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Re: Regulator size

Post by k36no4862002 »

No the challenger is slightly oversize with a sit in tender, true scale.it.would fit on 9" track, hence why the boiler is 2 " bigger in diameter.
It's based on the big boy locomotive in terms of scale that used to run on the Dobwalls forest railroad that closed down in 2006, a uk theme park which is where I got my inspiration from.
A Google search will find pics of the Dobwalls locos that used to run there.
Paul Edmonds,
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
k36no4862002
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Location: Surrey, UK

Re: Regulator size

Post by k36no4862002 »

Bill, James
I'll await the final drawings and calcs from the boilermaker so I can determine the steam generation, I don't think I will be short.of steam to drive 4 off 3.5" cylinders as the k36 boiler is smaller.and produces plenty of steam for 2 off 4 inch cylinders, once a train is moving its surprising how little steam is needed to keep it moving, the k36 registers about 30 psi pulling 8 cars hauling 70 people.
My regular question really was to see if my assumption of 1.25" is about eight, and so far that seems to be correct.

Paul
Paul Edmonds,
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
RThomp
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Re: Regulator size

Post by RThomp »

Very interesting! Yes I found this link :https://www.youtube.com/watch?v=pZLg4ydJCMQ

Looks more like 2 inch scale on 7.25 gauge track, much larger than 1.6 scale I think. That has to be about the largest locomotive I've ever seen operating on 7.25/7.5 gauge. Much larger than Tom Miller's big boy or Roger's design.
Last edited by RThomp on Sun Mar 12, 2023 2:20 pm, edited 1 time in total.
k36no4862002
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Re: Regulator size

Post by k36no4862002 »

The original inspiration for the challenger
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Paul Edmonds,
Surrey, United Kingdom.
2.5" Scale D&RGW K36, 1/6" Scale Challenger 4-6-6-4 (nearly done!!)
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Bill Shields
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Re: Regulator size

Post by Bill Shields »

Which is why I asked about PLAN at half boiler pressure
Too many things going on to bother listing them.
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