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Post by Jim on Nov 17, 2014 10:14:44 GMT
Thanks Pete, Paul and Roger for the comments.
The use of fibre glass strands would certainly be the way to go Roger if the structure was a bit less rigid than it is.
Jim
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Post by doncaster on Nov 17, 2014 10:15:02 GMT
Nice solution to an awkward problem and good end result. That should be strong as houses.
Mike
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Post by Deleted on Nov 17, 2014 11:08:10 GMT
That looks a very good solution to me as well ... I have the idea filed away for future reference.
Cheers
Tom
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Post by Jim on Nov 17, 2014 11:55:25 GMT
Hi Tom, If I was doing it again I'd make the 'fingers' along the straight sections 10 or maybe 20 mm wide. The greater width would still be easy to bend but would give a truer surface to work to. Must keep that in mind for when I come to do the cleading on the backhead.  Jim |
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Post by Deleted on Nov 17, 2014 13:29:32 GMT
Thanks Jim, I have made a note of that for the future.
Tom
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Post by Jim on Nov 18, 2014 7:05:02 GMT
I hate to say it but the more I look at the cleading I've just made for the top front of the fire box the more I can see it's not quite right.  Looking at a range of photos including JJ's superb 5" Britannia, my HO model of Boadicea and some small GA drawings I have I can see two problem areas. First on the real thing the 'corners' blend into the boiler barrel cleading just behind the hand rails. Mine come below the hand rails by 15 mm. Second there is a slightly deeper curve across the crown of the fire box compared to the almost flat top I created. Combined, the the two changes would create smaller less obvious 'corners' that would be much more in keeping with the prototype. Sorry folks but it's back to the drawing board for fire box cleading Mk2. Jim |
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Post by Roger on Nov 18, 2014 7:26:20 GMT
What a pain, but better that than find out later when it's all finished, you'd never rest until it was right.
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Post by Deleted on Nov 18, 2014 8:24:47 GMT
Good old Research & Development ( that last one literally)------ it's a "Bummer" at work or at home, eh ??..........If it looks right, then generally it IS right..........and our models are "on show" 100% of the time....Keep those chins up, eh ?? ( ooops--naughty me !!).........
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Post by Jim on Nov 18, 2014 9:13:46 GMT
What a pain, but better that than find out later when it's all finished, you'd never rest until it was right. You're quite right Roger, once you know something isn't quite right it has to be fixed. I've revisited JJ's Britannia Builder's site and among the photos he took while helping to restore Oliver Cromwell is a photo of the two sections of the cleading I'm trying to replicate. Pure gold. You can see them here at the bottom of the page. www.britanniabuilder.com/GCRvisit6.htmJim |
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Post by Deleted on Nov 18, 2014 9:23:01 GMT
Hi Jim Here's a photo that I took of 70013's throatplate cladding during restoration at Loughborough:  I think that the nicely rounded front contours that you have on your first attempt are spot on. Modelworks supplied this component CNC machined from a huge slab of solid brass, but they didn't round off the outer front corners sufficiently - I filed them down a bit, but not enough. I agree that there should be a very gentle curve across the entire top of the firebox, but only very slight. EDIT: You beat me to it, Jim! Regards, John |
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Post by Jim on Nov 18, 2014 9:50:46 GMT
Thanks for posting the photos John.
I'm glad you feel the rounded edge is right at least I'm heading in the right direction there. Shortly I'll sit down with the Eazy CAD and redraw the shapes to see how they fit.
I must say your Britannia looks magnificent and it is a great incentive to finish mine.
Have you been sailing lately?
Cheers
Jim.
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Post by Deleted on Nov 18, 2014 11:02:26 GMT
Hi Jim
It's getting a bit chilly for sailing here now! I've just ordered an Aster Gauge 1 Merchant Navy kit, which should arrive on Friday, so that should keep me busy for the winter.
Regards, John
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Post by joanlluch on Nov 18, 2014 14:44:00 GMT
I think there is misconception on why a superheater actually produces more power. It is not only that the superheater squeezes a bit more energy from the firebox. That factor is relatively unimportant. The increased power comes from the fact that the steam enters the cylinder at much higher temperature. Thermodynamic laws tell that the efficiency of any heat engine motor (this includes not only steam but also internal combustion engines) greatly depends on de temperature difference of the heat transfer that takes place. In the case of the steam engine if we assume that the outlet temperature is the same then you'll get the more power the higher the inlet temperature is at any given pressure. See this en.wikipedia.org/wiki/Heat_engineOn turbocharged internal combustion engines the increased power is mostly obtained because you enter more combustible on each cycle as you have more air to burn it. Still, for a given power, turbocharged engines are slightly more efficient than aspirated ones because when considered as a single unit the temperature at the turbo outlet is slightly lower than that of an aspirated engine. Joan |
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Post by Deleted on Nov 18, 2014 19:24:33 GMT
I think there is misconception on why a superheater actually produces more power. It is not only that the superheater squeezes a bit more energy from the firebox. That factor is relatively unimportant. The increased power comes from the fact that the steam enters the cylinder at much higher temperature. Thermodynamic laws tell that the efficiency of any heat engine motor (this includes not only steam but also internal combustion engines) greatly depends on de temperature difference of the heat transfer that takes place. In the case of the steam engine if we assume that the outlet temperature is the same then you'll get the more power the higher the inlet temperature is at any given pressure. See this en.wikipedia.org/wiki/Heat_engineOn turbocharged internal combustion engines the increased power is mostly obtained because you enter more combustible on each cycle as you have more air to burn it. Still, for a given power, turbocharged engines are slightly more efficient than aspirated ones because when considered as a single unit the temperature at the turbo outlet is slightly lower than that of an aspirated engine. Joan Hello JOAN-------- I think you may be in the wrong thread ?? |
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Post by Jim on Nov 18, 2014 19:27:22 GMT
Sorry Joan, but I think you have the wrong thread  Jim. Edit: While I was writing this Hagley Hall raced past me regulator wide open with the same message. Beaten again!  |
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Post by GWR 101 on Nov 18, 2014 19:36:52 GMT
Blimey Jim you are up early. Paul
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Post by Jim on Nov 18, 2014 19:42:30 GMT
Ah the joys of summer in OZ Paul. Sun's up, bird's twittering, and woke up early trying to decide the next move on getting the corners of the cleading right. It's a fun hobby isn't it? it?  Jim |
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Post by GWR 101 on Nov 18, 2014 19:51:50 GMT
Yes I still have that part to consider  so I am watching your thread with great interest, I am sure you will master it and the results will be to your high standard. Did wonder if you had got up to watch the coverage of a certain footy match, just about to kick off over here. Regards Paul |
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Post by Deleted on Nov 18, 2014 19:53:03 GMT
Sorry Joan, but I think you have the wrong thread Jim. Edit: While I was writing this Hagley Hall raced past me regulator wide open with the same message. Beaten again! -------------------------- and linked-up to 25% !! ( Because Rogers' after my "Low temperature" Swindon Superheaters..LoL !!) |
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Post by joanlluch on Nov 18, 2014 22:41:41 GMT
Hello JOAN-------- I think you may be in the wrong thread ?? Oops! I think I have posted it now in the right place. Joan |
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so I am watching your thread with great interest, I am sure you will master it and the results will be to your high standard. Did wonder if you had got up to watch the coverage of a certain footy match, just about to kick off over here. Regards Paul