jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Nov 26, 2014 13:41:07 GMT
hi richard,
by all accounts K.N. was a fully trained apprentice and time served engineer and spend many years maintaining 'stationary' engines for a large engineering firm in the midlands eventually ending up in the drawing office. many years later he formed the Kodak model engineering club and lived in Harrow - he worked for Kodak later on. he died in 1972 after retiring to Rustington.
he had an extremely well equipped workshop by all accounts and wasnt short of a bob or two - having owned a stanley (i think) steam car in his youth.
he rebuilt and built a number of award winning stationary engines (12 by all accounts), was a regular judge at the London exhibitions, was a member of the SMEE since 1927 and chairman and secretary for awhile, and had an encyclopaedic knowledge of engineering and railway locomotives as well as stationary engines. in the 1960s he stated he could design a miniature loco that would be better than a LBSC type, and ended up drawing out a 4-4-2 loco with very small cylinders, and i think his credibility suffered as a result and LBSC must have laughed his head off for weeks if not months at the time.
cheers, julian
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Post by Deleted on Nov 26, 2014 15:44:26 GMT
He had many a "Discussion" with Curly down the years..............."Hark, did something just stir down Rustington way" was one postscript I remember LBSC adding after just putting yet another one of his pet ideas into print in the ME mag..... If truth be known they either quietly admired and respected the others views and abilities, OR.....................HATED each others guts and the very space occupied within the atmosphere !!.......... Certainly there wasn't any middle ground....
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Post by Deleted on Nov 26, 2014 16:31:57 GMT
From what I remember, 'Cayenne' wrote quite a nice obituary on LBSC's passing. I think Martin Evan's was always quite complimentary about LBSC even though the feeling wasn't mutual. I get the impression that the only 'competitor' LBSC had any time for was Don Young who he helped quite a bit in his early days.
John
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Nov 27, 2014 0:44:07 GMT
hi john, the only contact between don young and LBSC was a postcard don received congratulating him on his 5"g ex-LSWR O2 IW 'Fishbourne' 0-4-4T design in 1967. don certainly admired LBSC's designs, but even don's first design Fishbourne was something quite different with valves between the cylinders and highly detailed and 'scale' even if of the wrong scale! don's experience with Gordon Chiverton's Maid Of Kent from 1968 onwards might have altered his view of LBSC - he re-designed the valve gear for it in ME in Nov 1969. cheers, julian
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Post by joanlluch on Nov 27, 2014 8:01:49 GMT
I don't think the Keiller ratio for tubes (length versus diameter) really matters. The Keiller ratio was supposed to give the most efficient heat transfer for a given tube size but it's now pretty widely accepted that only the first few inches of the tube contribute anything to heat transfer and the rest just carries the waste gasses to the smokebox without doing a great deal else. Therefore the length probably doesn't really matter within reason. I would assume this also depends on the thermal conductance or t'he material used for the boiler. On a cooper boiler, which is the most used material, that could be indeed the case, but not probably on a more general case. For example, one of the old members of my club has only used Stainless steel for his boilers, I think he eventually got a design that worked and then used the same, maybe with minor changes, for all his locos. In such case pipe length versus diameter could have a significant effect on heat transfer efficiency, as Stainless steel has obviously a much lower heat transfer figures than cooper.
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Post by Deleted on Nov 27, 2014 10:12:51 GMT
In 'our' sizes I don't think the thermal conductivity of the material makes a great deal of difference. We are only talking of thin material after all. A lot of people say that steel boilers don't steam as well as copper ones but in practice there is little, if any, difference. Actually, I find a steel boiler more thermally stable due to the greater mass of the thicker metal.
I think the problem with the tubes in small boilers is that there is little if any turbulence in the gases as they pass through the tube so you get a layer of stagnant gas adhering to the tube surface. This insulates the hot gas from the tube and prevents heat transfer. There may be some turbulence at the entrance to the tube as the gas passes over the edge of the tube which may account for most of the heat transfer being in the first bit of the tube. The gas flow then stabilises and you get the laminar flow in the rest of the tube. One way to get around this is to fit 'turbulators' in the tubes which are twisted lengths of stainless steel. The Americans use these a lot in gas/oil fired boilers and they make a big difference to the steaming of the boiler. They are perhaps not practical in a coal fired boiler due to the soot and ash but would be worth trying.
John
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Post by joanlluch on Nov 27, 2014 14:06:17 GMT
Hi John (Baggo). I think what you say has a lot of sense. On Stainless steel tubular heat exchangers corrugated tubes are sometimes used, specially where adding more exchange surface would be difficult or constraining. Search for "corrugated tube heat exchanger" to see what I mean in case you do not know them. . I wonder if such a tube could be used on a miniature loco boiler. You do not seem to be biased against non-cooper boilers so I thought I ask for your opinion. Thanks Joan
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fang
Seasoned Member
Posts: 100
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Post by fang on Nov 27, 2014 20:09:39 GMT
Just to be clear, at the moment I am only concerned with the boiler design re steamability. I am fully aware and have discussed on here in the past about materials, construction, etc required when building a boiler, but at the moment I am looking for any formulae to calculate the proportions of the boiler. As I feel the actual construction, materials, etc will be between me and the boiler inspector!!! My main concern is designing a boiler, building it and then finding that it will barely produce any steam!!!!
I like the idea of Flue tube/grate thread. Would it be advantageous to add a few more details, such as barrel dia, tube length, volume (if known). A couple of other nice to knows could be time to raise steam from cold, and steamability of the boiler when in use
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Post by ettingtonliam on Nov 28, 2014 10:51:43 GMT
Hi John (Baggo). I think what you say has a lot of sense. On Stainless steel tubular heat exchangers corrugated tubes are sometimes used, specially where adding more exchange surface would be difficult or constraining. Search for "corrugated tube heat exchanger" to see what I mean in case you do not know them. . I wonder if such a tube could be used on a miniature loco boiler. You do not seem to be biased against non-cooper boilers so I thought I ask for your opinion. Thanks Joan You are assuming the rest of are biased against stainless steel boilers. Whether we are or are not is irrelevant, the UK rules preclude the use of stainless steel boilers for models, so for most model locos and smaller traction engines copper is the only choice, changing to carbon steel for the larger stuff. Stainless is just not an option for us here, not for anything we wish to run in public or at a club track anyway. Personally, I'd be fascinated to see and hear about your loco when its finished and working, presumably with stainless frames, wheels, axles,cylinders, motion, boiler, platework, rivets (Riveting with stainless rivets should be fun) etc etc. A cost comparison to 'conventional' materials would be interesting too. I'm assuming you have ready access to small quantities of the various different grades of stainless in the required sections. Wheels and cylinders cut from solid, or cast?
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Post by joanlluch on Nov 28, 2014 20:23:52 GMT
You are assuming the rest of are biased against stainless steel boilers. Whether we are or are not is irrelevant, the UK rules preclude the use of stainless steel boilers for models, so for most model locos and smaller traction engines copper is the only choice, changing to carbon steel for the larger stuff. Stainless is just not an option for us here, not for anything we wish to run in public or at a club track anyway. Personally, I'd be fascinated to see and hear about your loco when its finished and working, presumably with stainless frames, wheels, axles,cylinders, motion, boiler, platework, rivets (Riveting with stainless rivets should be fun) etc etc. A cost comparison to 'conventional' materials would be interesting too. I'm assuming you have ready access to small quantities of the various different grades of stainless in the required sections. Wheels and cylinders cut from solid, or cast? Well, I made that assumption based on the fierce reactions to my mentions on S.S. boilers just after I joined the forums. I think said early comments were not just based on the UK rules, but on real disliking of the idea. I mostly avoided mentioning this subject again until now. In my country using S.S for a boiler is not an issue, I have consulted it. Basically, general rules for pressurised vessels apply on miniature locos. In fact, there is no separate rules for miniature locomotive boilers. Also the size and pressure of miniature boilers is below some limit that does not require official inspection. In practice, inspections are internally performed by clubs, they are connected and they only allow locomotives that are known to have been inspected. I suppose things still go like that because there are just a few instances of live steam locos, all of them known, and no accident has ever happened. So at the end of the day we are free to use any material for the boiler as far as the internal inspection is passed. I'm also aware that in France and Germany stainless steel boilers can be used, so they must be allowed as well on said countries. About making a comparison cost wise, I think this is very difficult because my approach to building the loco is very different. I intend to draw my plans so that the manufacturing of the parts can be easily outsourced to local CNC machining services. I only intend to perform some finishing and the final assembly, but not machining the parts myself. I live in an industrial area where I can find all sort of industrial materials/parts and plenty of services such as Laser/water cut and CNC machining services. I do not even have to bring materials to such services, they will just provide the parts already cut or machined according to the plans specifications, including the specified material. So the real challenge for me is to draw things in a way that can be really (and cheaply) produced. The resulting cost will be higher for sure than doing everything yourself, so this is why it is not possible to compare. However, my intention is to keep posting my progress with the hope that others can use some of my experiences. Even if my project is a total failure I think it is worth to share. Something I do not quite understand is why I am being questioned all the time. I do not see what is wrong with my approach, it's just different. About wheels, yes they are being made out of water cut, 18mm thick, AISI 304 S.S. Sheet. Then they will have to be machined. I have not yet a firm decision on cylinders material but I will possibly use AISI 303 + PTFE. The challenge here is to avoid at all times the contact of any metallic parts in the pistons with the cylinder liners. Cylinders will be made out of solid block, valve and main cylinder will be made as separated parts and then bolted together. High temperature resistant o-rings will be used to seal the parts together. I will not use any casts. Casts from S.S are possible but that is a technology that is only available to very important companies and big orders. I will not use any riveting.
I will avoid welded parts for as much as I can. Will not use a single one if I can.
Joan
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Post by Rob on Nov 28, 2014 23:47:16 GMT
Joan, I'm certainly eager to see your build coming together, lots and lots of photos please
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Post by ejparrott on Nov 29, 2014 8:31:11 GMT
I will not use any casts. Casts from S.S are possible but that is a technology that is only available to very important companies and big orders. Joan Bull poop. You need to do your research sunshine. There are all kinds of small insignificant companies selling stainless steel castings. Dave Noble does stainless steel cast wagon parts, a friend is making pattern to have a class 70 bogie frame cast in stainless - enough for one engine. Important Companies and big orders they neither are!
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Post by joanlluch on Nov 29, 2014 9:27:29 GMT
Hi Ed, I just downloaded the Dave Noble, and my understanding is that they provide ‘standard’ parts. I mean you probably can not just send them a plan and ask for a custom casting to be made. Unless I am wrong, of course. This was in fact my point. They probably negotiated the making of a number of parts to some casting foundry, not just one or two as it would be my case. I am able to order one laser cut frame (to say) or one axle, or one wheel, and so on, but not one casting. Much less if it was to be made of Stainless Steel. Actually, I would need to go far away to meet a foundry that would be able to produce Stainless Steel castings. That was my entire point. However, I have all the other services readily available just at few Km away.
Joan
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Post by ejparrott on Nov 29, 2014 10:07:16 GMT
I will not use any casts. Casts from S.S are possible but that is a technology that is only available to very important companies and big orders. Joan Bull poop. You need to do your research sunshine. There are all kinds of small insignificant companies selling stainless steel castings. Dave Noble does stainless steel cast wagon parts, a friend is making pattern to have a class 70 bogie frame cast in stainless - enough for one engine. Important Companies and big orders they neither are!
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Post by joanlluch on Nov 29, 2014 10:11:22 GMT
Ed, With all my due respect:
You wrote: “friend is making a pattern”. I wrote "send them a plan and ask for a custom casting to be made"
Do you see any difference on the above sentences, or am I missing something. As you know I am not English native, so I’d appreciate you clarify that for me.
Many Thanks. Joan
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uuu
Elder Statesman
your message here...
Posts: 2,808
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Post by uuu on Nov 29, 2014 10:12:43 GMT
You are fortunate to have a good availability of what you want locally. I had to get some S S from the US because the size and grade was not available here.
Wilf
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Post by ejparrott on Nov 29, 2014 10:20:17 GMT
There are countless pattern makers who will make a pattern if you can't. There are several foundries who will then make said casting. There are several processes by which said pattern can be made if you can't. There are several processes by which those several patterns can be turned into castings. If you want a one-off casting that is not a problem unless you want to make it one, which you seem to want to. A pair of bogie frames for a 5" class 70, how can you not see that that is a custom part and only a one off?
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Post by joanlluch on Nov 29, 2014 11:03:16 GMT
There are countless pattern makers who will make a pattern if you can't. There are several foundries who will then make said casting. There are several processes by which said pattern can be made if you can't. There are several processes by which those several patterns can be turned into castings. If you want a one-off casting that is not a problem unless you want to make it one, which you seem to want to. A pair of bogie frames for a 5" class 70, how can you not see that that is a custom part and only a one off? Hi Ed, I understood you are referring to a single part, this is not the issue. But lets see it this way: I am making my own plans for my own designed loco. Based on what I know from previous experience I decided that it would be easier for me to make some parts out solid block and machine them entirety from scratch. I figured out that doing so will be cheaper than following the castings route, if the design is simple enough. I also found this to be true if I am going to stick with Stainless Steel, because I didn’t find (or know) any nearby foundry that would be able to use stainless steel. Maybe if you are machining things yourself then making casts is a better approach because you avoid some machining. However, since I am outsourcing my parts to CNC services, the fact that the part has one less or one more machining steps is not crucial to the final cost because the expensive part is preparation and CNC programming (man hours time). Joan
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Post by ejparrott on Nov 29, 2014 11:46:27 GMT
You obviously haven't looked at my build thread, or registered the fact that I have said I am a CNC turner by trade. Prep and programming don't take very long at all. The expensive bit is the length of time it takes to machine, which you've made worse by deciding to make everything in stainless.
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Nov 29, 2014 12:01:28 GMT
I would have thought a person who claims to be an engineer would have chosen the best materials fit for each function and purpose.
Stainless steel in various grades has its uses but there are other materials and alloys that do a better job in many circumstances, why not use these.
Persons who have worked with stainless steels will know that as a generic material there are many places where its application is most ill advised. Perhaps my over 40 years professional experience is littered with seeing a more than average numbers of instances of stainless steel failure.
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