Model Engine Maker
Supporting => Boilers => Topic started by: Gas_mantle on July 18, 2017, 07:40:53 PM
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Hi,
I've just put a deposit on a Tubal Cain 5" boiler from a local hobby boilermaker who is going to make me a new one over the next couple of months and was hoping to find out a bit more background technical info about it. Can anyone please suggest where I may find out a bit more about things like its steam output volume, its water capacity etc ?
Thanks
Peter.
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Probably need to get hold of the model engineer mags it was in, around 1978 vintage
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Thanks Jason, was it released about 1978 ? I can't find out much about it online.
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Looks like the "five-inch shop boiler" was detailed in issues number 3591, 3593 and 3594 with a bit more in 3600.
Not ones that I have :(
Drawings and a few details here
http://gb.trapletshop.com/test-boiler-5-inch-m36
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Thanks, I'll see if I get hold of copies of the magazine articles.
From what I can see it seems to be a souped up version of the 4" GLR - I had a look at them in the flesh today and was impressed by both, the 5" is possibly a bit bigger than I need at the moment but at least it shouldn't need upgrading - I hope ;)
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I recon that horizontal you got the other day will soon have it empty, really depends on how much heat you can get into it to make more steam. Will you go for coal or gas firing?
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I'm going for coal, I'd like to think with 51 fire tubes it will supply a lot of steam :)
I've asked that the builder adds a steam blower (it seems some don't have them) and a connection to route exhaust up the chimney so hopefully I'll get good air flow. I did mention to the builder about the 2" bore horizontal engine I have and he is confident it will be fine.
I guess if I can find out its steam generating capacity that will help but the horizontal will happily run at about 60rpm from a small airbrush compressor under no load.
Has anyone got a similar size of boiler (or a GLR 4") and can say what size of engine their boiler can comfortably power ?
Peter.
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I looked up the articles, it's intended for coal firing, although TC had rigged up a gas burner. Expected to generate 10 to 12 lbs steam per hour at 80 - 100psi.
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Thanks Ian :)
I'm no expert in boiler technology so not sure how much 10 - 12 lbs of steam is (I tried googling it but drew a blank) do you have any idea what that is in ltrs ?
Is the amount of steam an engine needs simply a case of its cc multiplied by rpm? I have a moderately sized horizontal engine of about 120cc.
As it's double acting lets say it uses 250cc per rev or a ltr every 4 revs. Am I right in saying at 100rpm it needs a minimum of 25ltrs per min ? I'm very much in guesswork territory here but I'd have thought doubling that to 50 ltrs gives a good margin for efficiency losses etc
Anyone got any idea how much steam other small boilers produce by comparison - the GLR / PMR / Stuarts etc ?
Thanks
Peter.
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Am I right in saying at 100rpm it needs a minimum of 25ltrs per min
Yes, 25 litres/min, but if the cutoff is set to 50%, once the engine is running, steam intake would be reduced accordingly...
You have to look at table for the amount of water required per minute for that volume of steam, at the expected pressure.
then to check if the evaporative capacity of the boiler is large enough...
At a glance, imho, this boiler had to work very hard, coal fired, to provide steam to your engine at 5-6 bar (80 psi)
this a very large engine, for what I'm accustomed to...
this a steam plan I did recently
http://www.modelenginemaker.com/index.php/topic,7091.msg151802.html#msg151802
[youtube1]https://www.youtube.com/watch?v=GQS5PdLWZWs[/youtube1]
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Great video Zephyrin, thanks for sharing, also nice looking boiler and engine.
Thomas
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That's a great engine and boiler set up you have there Zephyrin :)
Have you any idea how much steam that boiler can produce ? Can it maintain its pressure if it was to run that engine at a higher speed ?
The boiler I'm buying is slightly smaller but with a greater number of fire tubes I'd expect it to be a bit more efficient.
Peter.