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Post by flyingfox on Mar 7, 2016 17:23:16 GMT
Greetings to you all, Can anyone please advise me where this locomotive was described by Don, was it in LLAS, or ME? A volume/ page reference would help. Thank you Regards Flying Fox
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oldnorton
Statesman
5" gauge LMS enthusiast
Posts: 693
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Post by oldnorton on Mar 7, 2016 19:53:38 GMT
Hi Fox The articles were in Don Young's LLAS from the 1990's. I have all the photocopies and photographs but not a precise list of the magazine numbers, sorry. The Black 5 articles are all in one bound volume I recall, and there were only four volumes. You can buy the photocopy set from Reeves but the pictures do not copy well. This thread shows a little more modeleng.proboards.com/thread/10498/5-inch-black. The exact copy numbers have been stated on here before but my searches are not finding it for you. The drawings are very good, I think, but I have not found the write up to be of much use. It follows the old LBSC style of telling you which piece of metal to cut next and to what dimensions, when it is far more helpful to understand why something is there and how it interacts. Norm
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oldnorton
Statesman
5" gauge LMS enthusiast
Posts: 693
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Post by oldnorton on Mar 7, 2016 20:03:21 GMT
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Mar 7, 2016 22:20:15 GMT
definitely not ME but only LLAS.
i drove the first completed example namely that by my old late friend John Edwards of the Cardiff Club (in those days the Whitchurch club).
the drawings are very good. there is slight problem (unusual for Don) of free gas flow through the tubes compared to grate area. Don was well aware of this subsequently. if you want a chat about this via PM then very happy to help. but it is cracking design and far better than Martin Evans designs!
cheers, julian
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Post by ramdango on Mar 7, 2016 23:07:42 GMT
If possible, I'd love to know the details gas flow to grate ratio. Or any other concerns re Don's Black 5
Cheers, Mountaineer.
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Mar 7, 2016 23:55:49 GMT
hi Ramdango,
the flue tube stack flow is quite restricted on Don's Black 5 compared with later designs and most of his earlier designs. having discussed the matter with Don many years ago i know Don was well aware of the problem. there isnt an easy solution - everything is constrained by the smokebox tubeplate. i think if Don would have had a second chance without any need to save his reputation he would have specified larger small tubes on a different arrangement.
i must add that getting Don to talk about past design problems was extremely difficult, and he was very defensive! he didnt let his guard slip easily! i was probably one of the few people he was prepared to occasionally discuss such matters with, if you approached such conversations in a roundabout way! a very good relationship with Don's wife Barbara helped a lot!
cheers, julian
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Post by flyingfox on Mar 8, 2016 7:33:49 GMT
Many thanks to you all, found what I wanted thanks to the help given. I had looked in LLAS, but obviously in the wrong place. Thank you Brian Flying Fox
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oldnorton
Statesman
5" gauge LMS enthusiast
Posts: 693
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Post by oldnorton on Mar 8, 2016 9:58:21 GMT
Julian
I respect your comments but, I am not sure that there is much of a problem with the DY Black 5 boiler design. Steve Eaton's won IMLEC recently (if I have got the event correct) and they are usually described as 'good steamers'.
I earlier used Jim Ewins' engine design formulae to work out all the figures for the DY Black 5 and they all come out to be very good. The Ewin three main calculations are: Eb = (grate area x tube length) / (no. tubes x tube dia. squared) Ef = (cylinder swept vol.) / (grate area x wheel dia.) Kt = (tube length / tube diameter squared)
Well proven engines (Jim's phrase) have Eb 80, Ef 0.15 Kt 80, and the DY Black 5 works out at Eb 79, Ef 0.13, Kt 77. So there cannot be a lot wrong.
Norm
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Post by Deleted on Mar 8, 2016 15:26:00 GMT
I earlier used Jim Ewins' engine design formulae to work out all the figures for the DY Black 5 and they all come out to be very good. The Ewin three main calculations are: Eb = (grate area x tube length) / (no. tubes x tube dia.) Ef = (cylinder swept vol.) / (grate area x wheel dia.) Kt = (tube length / tube diameter squared) Well proven engines (Jim's phrase) have Eb 80, Ef 0.15 Kt 80, and the DY Black 5 works out at Eb 79, Ef 0.13, Kt 77. So there cannot be a lot wrong. Norm, Interesting stuff, but I have a few questions for you! In considering the number of tubes and their diameter, how do we allow for the superheater flues? (Or do we just ignore them?) I take it the cylinder swept volume is times two for a two cylinder engine, times three for a three cylinder etc? In the formula for Eb, should it be tube dia squared? The answer comes out rather small otherwise. Ron
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oldnorton
Statesman
5" gauge LMS enthusiast
Posts: 693
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Post by oldnorton on Mar 8, 2016 19:27:56 GMT
Hi Ron
I can't explain why Jim Ewins chose these ratios, but reading his article I was happy to use his numbers as he had spent some time thinking about useful ratios to compare models. The article is in EIM and I think it is v3 No12 p359. When he compares engines it did seem as if the 'bad ones' throw up odd ratios.
My apologies, it was me typing too quickly. Eb (boiler factor) = (grate area (in2) x tube length (in)) / (no. of tubes x tube dia. sq (in2)).
The superheater tubes were added in for number but treated as having the same diameter as the flue tubes.
Yes, swept volume is the total of all cylinders per rev. For Ef it is ideally between 0.12 - 0.25
Norm
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Post by Deleted on Mar 8, 2016 20:45:58 GMT
Norm,
Running Don's dimensions through your corrected formulae, I get figures for Eb and Kt that are in the right ball park, but Ef come out to only half what it should be. It now occurs to me that for a two-cylinder engine, the swept volume is times four (not two) because each piston makes two strokes per revolution.
I'll now apply the formulae to some of my own projects, and see what results I get!
Ron
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Post by Deleted on Mar 8, 2016 21:06:52 GMT
hi guys
I've been reading the various comments here on boiler figures and wondered is there is a learned tome that a new person like myself to these things could read, digest and hopefully understand. I'd be interested to know how Doncaster's boiler stands in these things but would like to be able to understand good/bad points for myself in my own mind. I won't try to change Don's design in any way as that is well above my pay grade but would like to understand what if anything is effecting the design in a negative way. From what I've seen from completed examples running on the track and considering my limited experience in these things Doncaster seems to be a very good steamer..
Pete
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Post by miketaylor on Mar 8, 2016 21:12:29 GMT
If you go to John Baguley's home page (Baggo of this forum) you will find that he has taken a long look at these boiler parameters. Go to the LOcomotive design subsection. There is a fair bit of explanaton and a helpful spreadsheet.
Mike
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Post by mutley on Mar 8, 2016 21:15:48 GMT
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Post by Deleted on Mar 8, 2016 21:19:45 GMT
Thanks Mike...I know John, he's helped me a number of times in the past...I'll take another a look at his site..
cheers
Pete
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Post by Deleted on Mar 8, 2016 21:22:52 GMT
thanks Mutley....this will keep me occupied for a few evenings....
cheers
Pete
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Mar 9, 2016 10:59:09 GMT
hi Norm and Paul.
i did say that Don's Black 5 design was a cracking design and far better than Martin Evans' designs!
so far as the free gas flow is concerned i was only repeating what Don said to me privately many years ago... and if you read the last few issues of LLAS you will also see that Don committed to print the principles and proportions he thought best.
i wouldnt take too much notice of Jim Ewins' boiler formulae. it only works for certain types of boilers. other free steaming excellent boilers show up badly on Jim's formulae. there is a long list of different designs he compared in the original SMEE article.
cheers, julian
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beekay50
Active Member
Finished building 3 1/2 in G Heilan Lassie with Don Young Black 5 in progress
Posts: 26
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Post by beekay50 on Jun 10, 2019 4:55:51 GMT
I know this is an old thread but rather than start a new one decided to see if anybody is still looking here. I am building the Don Young Black Five and am now at a stage to build the superheater. I have a question concerning the length of the superheater tubes. Don's drawings show a what I assume to be the tube length of 16-24 for the outer tubes. I assume this means that the builder can choose how far the tubes reach into the fire box. Can anybody confirm this assumption is correct and if so what would be the optimum length for these tubes based on experience. My Black five has the standard wheel centres so it is a standard boiler length.
Cheers
Keith
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