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Post by Roger on Oct 31, 2013 12:47:34 GMT
I bought the plans for this engine from Reeves and have created a 3D computer model to verify the fundamental dimensions. This has thrown up some anomalies that I could use some advice on.
Fortunately I've not cut any metal yet. Maybe someone has built one of these and can guide me.
1) The position of the cylinders appears to be too far back to give sufficient room for the brake hangers.
2) The same issue also shows the crosshead fouling the gland on the cylinder cover.
I've seen that reported elsewhere with the suggestion that the connecting rods be made shorter.
3) I understand that there's another set of valve gear modifications by Don Ashton, but I have no idea where to get those from.
My instinct is to stretch the whole of the front of the locomotive by 1/8" to give adequate room for these things. Thank goodness for computer modelling,I'd be pulling my hair out if this had been built to the drawings.
Does anyone have any thoughts or opinions on any of the above? It's possible I'm wrong about this, but I can't see the error if there is one.
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Post by simon48 on Oct 31, 2013 13:21:59 GMT
3) I understand that there's another set of valve gear modifications by Don Ashton, but I have no idea where to get those from.
This article is in Engineering in Miniature Jan 2009. Don 'tidies' up the original LBSC version of the valve gear.
Regards
Simon
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Post by Deleted on Oct 31, 2013 13:44:14 GMT
Hello STRIPLAR and welcome..........Ah yes, SPEEDY!!....(I take it this is in 5"gauge ??).... OK, the bad news is that the plans from REEVES will no doubt be the ORIGINAL sizes as first designed by "Curly" Lawrence ( AKA "LBSC"--- but NOT the Railway Company of the same initials !!)...now here's the GOOD news}---- These problems that you are discovering have been known about for quite some time ( are you new to Model Engineering ?).. Indeed not long after the plans were first published a well known "sparring partner" of Curlys'... a certain Mr K.N. HARRIS...came up with some improvements in the valve gear layout, events, etc............ Others also have contributed to these improvements down the years so a "new build" loco such as yours should steam perfectly well right from the off....Incidentally back in the day it was quite easy to run the sequence of valve events on a "Drawing Engine" ( Posh name for a full-sized drawing board) to check out any problems before commencing production.... You really need to have a read of}---- "LBSC - His Life and Locomotives" by Brian Hollingsworth ( ISBN 0 86093 180 3 ) to get a feeling of what dear old Curly was all about.................Others on this forum will be along shortly to give more detailed info...Good job you haven't started yet, eh ??.........It's a great little engine when done properly so don't give up at the first hurdle ??------and do keep us posted !!-------------------------------------------------------------------------- AH, SIMON BEAT ME TO IT !!!!!!------------------ EDIT} Try putting}-- lbsc speedy modifications ---- into Google search and have a trawl around..Lots of help there as well.
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Post by Deleted on Oct 31, 2013 16:43:36 GMT
Hi Striplar Welcome to the forum... quote: 3) I understand that there's another set of valve gear modifications by Don Ashton, but I have no idea where to get those from. Why not send him a PM here on this forum although I'm sure if he see's this he will contact you anyway.. his ID is er... Don Ashton..  Kind regards Pete |
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Post by donashton on Oct 31, 2013 18:42:13 GMT
Well, thanks everyone - I'm in touch with Striplar. It may be opportune to write the following.
1) LBSC's Speedy is based on the GWR 15xx shunter and faults or not many have been successfully built.
2) The valve gear was devised with pins and cardboard and the cramped wheelbase inherently does Walschaerts' gear no favours.
3) With valves not matching the ports expect a sluggish performance.
4) KN Harris missed the point, only providing more full gear valve travel.
5) Don Young fancied copying the full size absence of a drop link, which gave rise to problems in FS.
6) I managed better valve events and full gear without the lifting arm reaching a silly angle. My article in EIM gives suggestions to avoid close contacts. I hate having to tell someone that half the parts need to be remade unless absolutely necessary.
Don.
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Post by Deleted on Oct 31, 2013 23:42:33 GMT
Aside from the valve gear issues, there are other aspects of the design that you might like to look at before you cut too much metal.
The boiler profile is to the overall shape of the full size boiler with the cladding on, so by the time you've lagged it, it will be oversize.
The five element superheater was probably ahead of its time and is one of the good features, but you need to make the front ring of the smokebox removable, to stand any chance of getting the thing out when it needs attention.
Strangely, LBSC didn't show a balance pipe between the water tanks. This needs to be planned for, before you make the tanks.
The ashpan is completely open at the bottom. It will admit plenty of air to the fire, but you will be unpopular with your club when you continually set fire to the sleepers!
LBSC didn't have a clue as to what a 15XX looked like from the back, so he guessed and got it wrong. For the sake of the bus fare from his house in South London to Old Oak Common, he could have seen for himself. The rear buffer beam isn't a repeat of the front one - it's much wider and deeper, and if made correctly you won't need LBSC's ridiculous apron plate.
LBSC's reach rod is cranked to align with the reversing lever in the cab. On the full size loco, the reach rod is straight - it's the lever that is cranked.
If you really want to be accurate, the 15XXs were most unusual (for the GWR) in having inclined cylinders. The cylinder angle is 1 in 48, but every Speedy has them horizontal. Take a look at the 7.1/4" Paddington design for an accurate representation.
Speedy is generally acknowledged to have been one of Curly's worst designs, and as far as I know he never built one himself. That hasn't stopped many hundreds being built around the world, and most have been made to run successfully, so take heart!
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jma1009
Elder Statesman
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Post by jma1009 on Nov 1, 2013 0:32:13 GMT
thanks superseven for a most comprehensive reply, and as always to Don for his always generous help.
not the sort of loco i would advise a tyro to build/attempt, given the valvegear deficiencies and other problems. the Reeves drawings should incorporate the don young valve gear modifications if you bought the additional sheets though these are no where near as good as Don Ashton's re-design. my own comments are directed at the appalling backhead arrangement of the fittings which is quite atrocious. the only really decent examples ive seen and driven (and ive driven a few that were NOT!) have been built by very experienced model engineers who knew what they were doing. the late Bill Perret's example from the southampton club was an IMLEC winner 2 or 3 times, but then Bill knew what he was doing! the belpaire firebox and tapered barrel isnt an easy job in any event, plus the piston valves.
cheers,
julian
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Post by donashton on Nov 1, 2013 11:01:49 GMT
I think that we should recognise the difference between building a Curly engine and building a GWR 15xx class. Since his time the hobby has produced far more authentic reproductions than previously, but without Curly and his contagious enthusiasm today's scene would look a lot different.
Don
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Post by Deleted on Nov 1, 2013 15:01:17 GMT
--------------quite so,DON....hence my advice for STRIPLAR to have a read of Brian Hollingsworth's book and "understand" our dear departed friend before commencing work...As the majority of us old 'uns know Curly's loco designs were initially aimed at the raw beginner...having been built and tested by himself first ( or concurrently)...Oddly, this one doesn't seem to fit any of his own parameters.... I ran one for less than a year, couldn't get on with it (original design) and wasn't prepared to do a serious re-build, time being against me in those days.....so it was sold...Personally, if STRIPLAR wants a 5"gauge PROVEN 0-6-0T then my personal favourite is good old SIMPLEX....but then that's just me.....
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Post by donashton on Nov 4, 2013 12:03:20 GMT
I think that it is worth noting that in assisting Striplar with his query I have the aid of simulation. By this means I have been able to see exactly how LBSC, KN Harris and Don Young (who had no such opportunity) missed the points of error and unwittingly created many problems themselves. This gives rise to different con rod and radius rod lengths and tight fits or even clashes with the bracket frame. Builders take care.
Although a model of a small shunting engine Speedy in 5" can be an excellent track locomotive capable of pulling large loads.
Many years ago I was asked by Alec Farmer to comment on safety valves, one of which was Speedy. I recall rather tongue-in-cheek suggesting that it would be more efficient upside down! Nuff said.
Don.
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Post by Roger on Nov 6, 2013 0:50:43 GMT
Hello STRIPLAR and welcome..........Ah yes, SPEEDY!!....(I take it this is in 5"gauge ??).... OK, the bad news is that the plans from REEVES will no doubt be the ORIGINAL sizes as first designed by "Curly" Lawrence ( AKA "LBSC"--- but NOT the Railway Company of the same initials !!)...now here's the GOOD news}---- These problems that you are discovering have been known about for quite some time ( are you new to Model Engineering ?).. Indeed not long after the plans were first published a well known "sparring partner" of Curlys'... a certain Mr K.N. HARRIS...came up with some improvements in the valve gear layout, events, etc............ Others also have contributed to these improvements down the years so a "new build" loco such as yours should steam perfectly well right from the off....Incidentally back in the day it was quite easy to run the sequence of valve events on a "Drawing Engine" ( Posh name for a full-sized drawing board) to check out any problems before commencing production.... You really need to have a read of}---- "LBSC - His Life and Locomotives" by Brian Hollingsworth ( ISBN 0 86093 180 3 ) to get a feeling of what dear old Curly was all about.................Others on this forum will be along shortly to give more detailed info...Good job you haven't started yet, eh ??.........It's a great little engine when done properly so don't give up at the first hurdle ??------and do keep us posted !!-------------------------------------------------------------------------- AH, SIMON BEAT ME TO IT !!!!!!------------------ EDIT} Try putting}-- lbsc speedy modifications ---- into Google search and have a trawl around..Lots of help there as well. Many thanks for the welcome, yes this is 5" gauge. I'm returning to Model Engineering having been very interested as a teenager but frustrated by the lack of equipment and poor attitude of the Southampton Model Engineering Society of the time. I've spent a lifetime in engineering designing CNC control systems for PCB drilling machines, and now have the idea workshop to tackle this kind of build. It's a pity that all of the accumulated knowledge about Speedy isn't conveniently located in one place so that every new builder has to discover all of these problems and solutions anew. I propose to start a Wikipedia page for this shortly and hope that it will become just that. My heartfelt thanks go to Don Ashton for his patience and wealth of valuable information about the valve gear. I've now incorporated this into the model and it fits very nicely. I'll endeavour to supply the drawings of the modifications for others once I'm sure they are correct. I've decided to plough on with as near to a complete 3D model as I need to make to verify that there are no other unexpected issues. I hear what some builder say about this not being accurate to the original loco, but to be honest I'm really not that interested in authenticity. A good build that works well and doesn't have any nasty building issues is more important to me. I'll do as you suggest and dig up as much information as I can. Here's a taste of what can be achieved with Geomagic Design. Currently the valve gear cut off can be set by moving the handle with the mouse and the motion responds to that. The mouse can then be used to turn the wheels to verify that everything moves as it should. This is a geometrically precise model, on that can be used to generate the G-Code to machine the individual parts. What you see is what you get. If it looks wrong, then it is wrong.  |
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jma1009
Elder Statesman
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Post by jma1009 on Nov 6, 2013 13:46:27 GMT
hi roger,
i must be in a very negative mood this week - must be the weather - but with all your engineering experience i think you would be much better off building something like don young's BLACK FIVE or another proven design without the many problems SPEEDY has. i think you will be continually pulling your hair out otherwise! don young's L&YR Aspinall 0-6-0 is a beautiful loco if you like the Victorian locos.
apart from LBSC's outside cylindered MAID OF KENT and his MINX with joy valve gear all his 5"g designs have significant 'problems'.
if you still fancy a 15XX and have the machinery then the Reeves PADDINGTON is worth looking at in 7.25"g.
i usually start with considering the boiler and how easy that is going to be to make. a round top boiler with parallel barrel is much easier to make than a belpaire firebox tapered barrel type. i dont think i will ever make another GWR type belpaire firebox tapered barrel boiler.
i would never advise anyone to build SPEEDY!
cheers,
julian
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Post by donashton on Nov 6, 2013 16:29:33 GMT
Be fair, friend Julian. People don't choose what they want to build according to advice. Nor are all those put forward free from iniquities. The very first builder of Paddington hit a brick wall from the drawings - I know because I was charged with an urgent solution. It's my bet that in making that beautiful Terrier you've had oceans of fun finding the unsuitable bits and devising good working replacements. The goal is a good runner that looks right, but there are hours of pleasure in model engineering long before the conclusion. Whatever would we talk about in the clubhouse if everything went right?
Don.
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Post by Roger on Nov 6, 2013 19:41:52 GMT
Sadly we enter into these things with incomplete information else I might have made a different choice. I imagined that Reeves would only sell plans for this locomotive that had been tried and tested for 50 years, not the can of worms that these things can become. Heaven knows they've had long enough to do something about all the errors and omissions. To my mind that's lazy at best, and willfully negligent at the worst.
Still, I've bought the castings and love the way this pretty little engine looks so I'm happy with my decision even though it's proving to be more challenging because of all the issues.
This is just one thing I fancy building, it's not going to be something I'm going to be using much anyway. It's not my scene to be down at a track with it very often. I could have tackled something spectacular but I don't think I'd have the interest to finish something like that.
I doubt very much if I'll build another locomotive, so this one may as well be built to the best of my ability and maybe I can contribute something by way of plans so that future builders won't have to tread this painful path again.
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Post by Roger on Nov 6, 2013 23:08:41 GMT
Another quick question that arises out of trying to draw the boiler, is what is the minimum internal radius for the flanged plates. I was under the impression that this was approximately the same as the thickness of the material, but visually, it looks considerably less on the drawings. I've read the book but can't see any reference to what the radius should be.
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jma1009
Elder Statesman
Posts: 5,917
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Post by jma1009 on Nov 6, 2013 23:18:45 GMT
hi don,
yes you are very correct, and of the few locos ive built to published designs the drawings are pretty much in pristine condition having in most cases never been looked at! i do however sympathise with roger's predicament. good luck roger!
cheers,
julian
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jma1009
Elder Statesman
Posts: 5,917
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Post by jma1009 on Nov 6, 2013 23:28:31 GMT
roger,
have a very close look at the boiler. the standard 10 boiler had a manifold flange on the backhead and the fittings are nothing like the LBSC design. have a look at the SVR preserved loco. the boiler is deficient in a number of respects - no bushes for the fittings and inadequate staying to the inner firebox doorplate above and around the firehole, and the tube arrangement can be considerably improved upon IMHO. when making the flanged plates there is a small degree of thickening of the flanges - but often this is filed off so the forming blocks can be made just say 1/64" overall less than the thickness of the flanged plates. hope this makes sense.
cheers,
julian
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Post by suctionhose on Nov 6, 2013 23:43:01 GMT
jeez there's a lot of spoilt boys about these days!
Don't know how many of you have had your original designs published but let me assure you there is alot of work to do so. And the design continues to evolve in peoples minds long after it is committed to print.
There are no perfect ME designs. Due credit should given to those generous souls that have given so many people a starting point.
LBSC? The man was super human! A Britannia design in print the same week as the first fullsize entered service? Unbelievable!!!!
Julian you really must use your considerable presence on here to encourage others in their choices and not try impose your own upon them.
Build whatever you want Roger and don't ask for anyone's approval.
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jma1009
Elder Statesman
Posts: 5,917
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Post by jma1009 on Nov 7, 2013 0:30:37 GMT
hi ross,
my concern with roger and others is to warn the otherwise keen and enthusiastic builder of the pitfalls of some of the well known published designs, and so be pre-warned and not get fed up and disheartened at a later stage. alan stepney (one of our moderators) has an excellent site detailing errors in published designs and there is a thread on here too with same. i agree build whatever you want but as roger has very early on found out some of the published designs have a number of very serious flaws that will often lead to disappointment and much gnashing of teeth etc!
as for LBSC's BRITANNIA the throatplate flange design is seriously deficient and i know of many club boiler inspectors who wont accept a new loco built to the published boiler design.
cheers,
julian
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Post by Deleted on Nov 7, 2013 1:20:52 GMT
Hello again STRIPLAR--------- i'm much impressed with your dexterity on the CAD etc........Here's my main "Drawing Engine" whilst the other one is a 6ft x 2ft piece of 3/4" chipboard to cater for full size mainframes on the 5" Bear............. Attachments:
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