New Start on LBSC's 3.5" Petrolea

About to start on an LBSC 3.5" gauge "Petrolea"

I have been told that LBSC never did build one of these locomotives, and that the drawings have a LOT of errors. I have tried searching for drawing error lists, and cannot find anything pertaining to "Petrolea"

Anyone here who has built one, or is building one, and has any advice?

Thanks for any help!

There will be errors.

Check , using drawing dimensions, that if anything rotates it does not clash with anything fixed .

That , valve gear has clearances at all points of travel with other fixed or rotating items.

In short , check everything before doing anything drastic.

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I have a part completed one, inherited from my grandfather. I think he would have started it "in period" and got as far as completing the chassis, motionwork and boiler before leaving it on a shelf for 50 years+. I have run it on air which seems OK, so if you want anything measured from an as-built version then shout.

I have most of the original ME issues and a set of plans purchased later, and I recall I found some pictures in the Station Road Steam archive if you haven't discovered those already.

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SRS number 7987 appears to have worked (edit: perhaps not strictly a Petrolea?)

https://www.stationroadsteam.com/3-12-inch-gauge-ger-t19-4-4-0-stock-code-7987/

Edited By Adrian R2 on 08/02/2021 10:45:53

Well, although it is not named Petrolea, it IS an LBSC GER T-19, so it IS the locomotive I am asking about. So at least ONE was successfully completed. I just wonder how much rework was involved.

Thanks very much!

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I am afraid the advice to "check every dimension" is not very practical. It would mean examining each part, and laying it against each other part. If I had skills at Autocad or something similar, I suppose it could be done, but it would take months to draw everything up, put it all into the computer and then run simulations to see where problems are at, and I have none of those computer skills, and no such computer program anyway, so that isn't going to work. .

I was really hoping that someone would have an already-compiled-list of the known big problems. I have been told that someone compiled such a list, but have not been able to find out where it may be.

I am aware of the boiler to frame fit. Also, the possible knocking of the crank pins. I am also concerned with valve gear errors that may make successful completion of an example of this locomotive impossible to do.

I think the number of part-built chassis around is a pretty good indication that there are some major problems. I just wish I knew what they were. I expect this to take me about 5 years to construct, so this project would be a major investment in time, along with all the castings, materials, boiler copper, etc.

I guess I can take it one step at a time, and try and check the next step dimensions before I go ahead, but I can foresee a lot of delays, while I do that, or in some cases, while I figure out the best way to accomplish checking things.

Sure wish the vendors would correct their prints. My set of drawings is only 2 years old, and is from Kennions. But the design has been around for nearly 80 years now, and things are STILL not right?.

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It ISN'T unhelpful and it is NOT non-practical advice, BR! Please don't be insulted!.

It is just something that would be beyond me, the same as re-engineering one of these locomotives from scratch. I am an excellent machinist, and can (and have) made nearly anything, but my engineering skills are very limited. I would have a hard time making ANY kind of modification to a valve gear set, for instance, since I have very little knowledge of what differing changes might do, and have only the fuzziest grasp of how they actually work in the first place. .

If I built the valve gear per the LBSC print, and it didn't work, I would be completely lost as to how it could be corrected. .

When someone tells me: "Here are the drawings from the Master, LBSC, now, look them over and improve them!" I would have no idea where to even start.

With respect William along with me and many others your are probably more hobbyist that design engineer. LBSC was quite an inspiration in his day but his was a different era. Yes there will be errors and the old drawings are rarely updated so you just need to keep a look out as you go along and take remedial action as and when. I think there are numerous part-built chassis from all manner of projects not just Petrolea so I wouldn't read too much into that ... models often didn't get very far and I've got three of them under the bench waiting to be rescued. Go for it and visualise a finished loco, and in Ultramarine Blue ... magic!

Although LBSC famously claimed to provide 'words and music' it wasn't always true, and the man made mistakes. I feel much of his later work was intended to inspire experienced engineers and not aimed at builders at all. Outline drawings rather than the fully developed and checked plans makers need. Didn't help that LBSC became more intolerant as he aged, and often responded to legitimate questions and criticisms with sarcasm.

Don't get me wrong, I think the man was a genius, but being a real human meant he was also imperfect!

Many engineering drawings are faulty. Draughtmanship is a difficult skill - ambiguities, mistakes, omissions, you name it. So I always do a degree of checking, usually straightforward. Although I can drive Fusion 360, I've never modelled a whole design in 3D CAD just to check it. I'm more likely to:

1. Eyeball hole and straightforward length dimensions to ensure they match where they should.
2. Confirm marked dimensions are compatible with the scale of the drawing and each other with a scale rule (which can be home-made) and a pair of dividers. Dimensions obviously more important than others get close attention and I don't bother inspecting parts that would be cheap and easy to fix.
3. Redraw any part of the plan that's not bleeding obvious! On the back of an envelope is often enough. When in doubt, I redraw more formally on squared paper, or go fully dimensioned in 2D-CAD, or in 3D. 3D-CAD kept simple is very helpful because suspect parts can be 'made' and rotated to confirm they make sense. 3D modelling often indicates how the real job should be done too.
4. I never build several parts from the plans and then try to assemble them. Instead, I order the build in a way that lets me use existing parts and assemblies to gauge other parts before and after making them. It's fitted together the old-fashioned way, and 'fitting' might include tack quite a lot of the mechanism together just as a dimensional sanity check. I don't hesitate to mock up parts from Lolly Sticks or whatever to confirm sizes before cutting metal. Cardboard templates; these can be used to ensure the valve gear makes sense. If the cardboard version misbehaves, ask!
5. I put a fair amount of thought into getting reference points of complex objects right. Not rocket science, because parts always have an edge or two, or a hole, from which everything else is measured, and which can be related to other parts. With thought, the build can be ordered to progress from reference to reference, and planning to do this tends to flush out drawing errors and misunderstandings.

Checking designs shouldn't be an appalling amount of work. Planning to build from a good design doesn't take long. If understanding the plan causes lot of trouble, then maybe the design so flawed it isn't worth building. For example, if I found the boiler wouldn't fit the frames, I'd be seriously concerned the whole thing was a dud.

Does anyone else have any suggestions? I'm sure there are other good ways of validating plans before building.

Dave

Dave

I have a full 3D model of the Don Young Aspinall I am building and I work from that not Dons drawings, only using them to tick off what parts are finished.

However for someone who has no access to CAD I think you have got it about right. The only thing I would add is that the critical parts can be easily checked as an assembly on a drawing board. You do not need to fully detail each part or all parts only the bits that interact with each other. After all this was how the loco would have been designed and how things were done before CAD. I reckon with a full set of drawing available you can do it in 3 or 4 days tops.

Dave

Many published designs have errors and these tend to be more frequent when the design has not been built by the designer before publication.

Obviously the designers who published more designs published more unbuilt designs, so people like LBSC and Martin Evans might include more errors, but that is just the nature of the game.

If you get the opportunity try to read the original magazine articles - in a library is a good place - as there you may well find the answers to errors in the published drawings.

I dug out my plans for Petrolea last night. They say they originate from Donaldson & Piper, Kent, with the "Copyright" to LBSC crossed out! I bought them s/hand so don't know if they are the same as the Kennions ones.

VERY interesting!

I was thinking about the print problem. If you corrected prints and started selling copies, I think you would be fine.

Doesn't the copyright holder have the rights?

YOU BET!

THEY HAVE THE COPYRIGHT ON A DESIGN THAT DOESN"T WORK!

If you correct all the errors, and copyright the new, corrected design, then YOU will own the copyright on THAT.

This would be one solution to companies that don't correct their drawings over long periods of time. They can't claim it is THEIR design, because it ISN'T!

THEIR design doesn't even function, and in many cases, cannot even be constructed.

I think if it went to court, their case would be pretty weak, considering the fact they never made any effort to correct errors or insure the design even worked. They demonstrated no actual interest or care in their design, so it would be a long legal stretch to show they really, really DID have an interest in their design if they never actually tried to make it work.

Just a thought.

.

I think you will find that you would still be breaking copyright with your new corrected drawings as they would be classed as being derived from the originals and so still covered by the original copyright. It's probably very complicated!

John

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Oh, GOODY! Stirring the pot!

I had hoped there will be a lot of comments on this!!