Not the 92219 thread

Original Riddles 2-8-2 plan, anyone?
:behindsofa:

 

Re: 92219

That would require a Britannia boiler.

 

Re: 92219

Well I was joking, but if we're going to discuss it then I disagree. Not necessarily.... It would need a Britannia-style firebox (deeper, and level, whereas the 9F's firebox is designed the clear the rear driving axle). The barrel, tubeplates etc. would be ok, assuming they are ok anyway.

The 2-8-2 driving wheels are bigger, and the axle spacing totally different, so you would be looking at brand new frames aft of the cylinders, brand new driving wheels, a pony truck and trailing wheelset, new ashpan, revised running plate and pipe runs, and revised cab.

Apart from that it would be easy.

 

Re: 92219

Having studied this at length and in some detail the only Major components you could use from a 9f on the 2-8-2 as designed would be
Axles and Axle boxes
Pony truck with a bit of surgery and wheels/axle
Cylinders/slide bars/ motion brackets (maybe)
Plus any 'standard' components ( which are the first things to go of barry 'wrecks') including the cab

Thats not to say you couldnt rebuild the back end and lower firebox of a 9F to create a 2-8-2 of sorts and it would probably be a good loco to boot...
but the idea of building a locomotive designed around a specific boiler using components from a Similar looking loco designed round another (quite different) boiler is boll... erm optimistic

 

Re: 92219

Perhaps before anyone gets too excited, someone ought to ask the owner whether he wishes his new acquisition to be turned into a 2-8-2! Seriously, as Evening Star was a bit special with the green livery and name, I'm just pleased that the last "run of the mill" steam loco built for BR has a happy future as a working loco.

 

Re: 92219

Hear, hear

 

Re: 92219

Yes, that's why it was said in jest - you can salvage some components but a lot of it would be new.

But having said that, most of a "Barry wreck" restoration is often new anyway.

And relative to the overall level of hassle involved in doing all that, modifying the plans to suit a hybrid 9F / Brit style boiler wouldn't really be that difficult in the general scheme of things.

 

Re: 92219

Joking....

I was joking....

J O K I N G

J O -

Oh, never mind.

 

Re: 92219

Don't worry - I was aware!

 

Re: 92219

Well as relativity goes, suppose your right. If only it was quite so simple to cut and shut bits of loco.
Until you sit down with a set of plans and work through the implications of swopping this bit for that ..
Happy to see another 9F restored as a 9F, or not.
Happy to see a new Clan, a new P2, a 47xx
Happy to see the euromillions win that will pay for them all, plus a fully restored Merchant Navy, a Bond/Cox 2-8-2 straight off the drawing board...

 

Re: 92219

Don't forget 92245 is available for the 2-8-2 people, if they wish to purchase it and start again.

 

Re: 92219

Well, I don't rule anything out these days.

I can remember pouring considerable amounts of scorn on the Bluebell Atlantic project (which is itself a part cut-and-shut, part new-build scheme) in conversation with some of the team members about 10 years ago, on the basis that it was an expensive folly when there are still unrestored engines left waiting for repair. It offended the completist in me.

The response was simply that creating an engine largely from scratch is in many ways cheaper and easier than restoring a wreck. There's no tiresome dismantling and conservation work to be done on the remnants you're starting with, no arguements, risks or value judgements to be made on how deep the restoration work needs to go, and no concerns over remaining weak links when it's finished. You know exactly what you're dealing with at every stage, the vast majority will be good for years to come, and you can design-in modifications from the outset rather than having to bodge what's already there to make it fit.

10 years later the progress is truly remarkable, and I have to concede that they're probably right.

Hughes 4-cylinder compound pacific, anyone?

 

Re: 92219

With gas producer firebox, Porta draughting, roller bearings and caprotti valve gear? Why not, or is this 5AT reincarnated in a more orthodox envelope? Really, the 9F based option doesnt't deliver the desgn intention: too many parts (wheels, frames, probably cylinders as well wouldn't be any use). It's ages since I read E S Cox on the subject, but I seem to remember that the 9F boiler was based upon that for the Clan, but I'm prepared to stand corrected.

David

 

Re: 92219

Not entirely correct but dimensionally its - a clan smoke box, shor ened brit boiler stuck onto a clan shaped firebox with the Grate made shallower and longer...

I suppose if your going to incorporate riddles belated vision for the ideal alrounder youd have the Caprotti and 5ft 6 drivers too.

 

Re: 92219

Despite the design differences between 9F and Britannia boilers the overall grate area ended up much the same (40.2 sq ft for a 9F versus 42 sq ft for a Britannia). Far from preventing good steaming, the shorter 9F barrel improves it, thus 'compensating' for the 1.8 sq ft of grate lost - if that were ever necessary (!!). Though of course as the back and sides of a 9F firebox slope outwards, making the firebox deeper would also make the grate area marginally bigger....
:rockon:

The achilles heel of the 9F was the compromised ashpan design, which obviously wouldn't be an issue with the 2-8-2. So that adds further potential for higher steaming rates as well as making the P&D work easier for the crews. A deeper, flatter grate would make it even easier to fire, too.

I'd be wary of Caprotti gear - I understand 71000 needs fairly continuous firing as the crisp exhaust pulls the fire to bits very quickly. As reported elsewhere the twiddly bits also require very specialist know-how when they go wrong. The double-chimney 9Fs were particularly free steaming and economical, ashpan issues notwithstanding, so conventional gear and a twin blastpipe might suffice? :thumb:

 

Re: 92219

Hadnt heard anyone mention the firing foilbles of the current version of 71000 before.... but any Grate that big can't be left alone for long.
As for caprotti bring it on, the more exmples there are in use the more people know, the less 'specialist' it becomes.

Brittania boilers we're designed to provide all the steam neccessary 'ticking over'. The boiler dimensions of the 9F are a marvel given the space they occupy. I dont think Riddles thought they would ever be worked as hard and as fast as they we're but the boiler was up to it... Compare the Stats with those of a WestCountry or V2 .

The real dilemna is the Clan boiler - there is certainly unfinished business here as regards the Draughting - Personally i think the Flues/small tubes balance is off too

 

Re: 92219

Don't get me wrong, I've always loved the concept of Caprotti gear, but the feedback from those I've spoken to is that 71000 is "hard work" relative to other locos, if compared on similar runs. Hard work for the same outcome seems a bit pointless to me - fair play if it's justified by enormous increases in economy or performance compared to everything else, but is that really the case? Certainly a Duchess, Merchant or King can be "banked up" before departure and the fire bed will remain relatively stable thereafter, though of course it will erode over time if not fed. However they can go an awfully long way with what's already in the box! I understand that LNER pacifics prefer thin fires with 'little and often' firing - obviously I say "understand" because I've never actually been on one, so the normal "armchair expert" caveats apply. 9Fs and Britannias occupy the middle ground, requiring a fire of medium thickness and fairly regular, but not intensive, feeding with fresh coal. Now it may be that in tweaking 71000 it's been made a bit too sharp, but the story is that even with a thick fire it will spit most of it out of the chimney / into the spark arrestor quite quickly if left to its own devices. Now I'd imagine quite a bit of that fuel would be unburnt, so it's not necessarily fuel efficient. Now whether that's automatically the case with Caprotti gear is a good question - can the draughting be toned down to give a more reasonable compromise, or is fire-throwing always the result? Could it be that Caprotti + Kylchap is overkill... just too sharp, too clever? It certainly seems pointless when conventional valve gear and draughting seems to produce similar levels of performance and for considerably less cost and hassle.

There were similar debates over the Nelsons where 8 beats per revolution plus a multiple jet blastpipe must have produced a very intensive, almost continuous draw on the fire. Wonderful in theory but it never really seemed to pay off in reality?

Incidentally don't be fooled by boiler "size" in overall terms. The best boilers are short and stubby, which is why Beyer Peacock Garratts were so successful - with nothing to get in the way on the central frames, you can construct whatever you want, and that was always something short and fat with a big firebox. Long boilers, particularly long parallel boilers, are nearly always 'cold' at the front end, with tubes far too long to give optimal steaming. That's one of the reasons why most of the early pacifics were such a disaster area (Raven et al), and why some of the longer boilers found on more modern machines had combustion chambers.

I wonder if that was the issue with the Clans. The boiler barrel is too long relative to its diameter and the grate area? Certainly tube dimensions become very critical in such circumstances. A shorter barrel and bigger firebox for the 9Fs would have changed the relative proportions favourably.

 

Re: 92219

Think part of the problem your describing comes from 71000 being driven as any other loco, it will do the job on much shorter cut offs. The blast pipe dims have now been opened so its less sharp than it ever was, and 6 beats gives a more even draw than 4... so your report seems a little counter intuitive.

Nellie is another loco that hasnt had much form of late mostly due to firebox problems, But back in the 80's performed as well as any Class 7, being a prticularly steady starter/climber....

The biggest, and longest boiler im aware off is the 'Duchess' which considering it was designed under the auspices of Stanier without a history of big f'off superheated boilers is a masterpeice, but it does have a big firebox...

The Clan Steam circuit was not as effective as the Other big standards for sure, and you may have put your finger on the resons why, but i never heard of one ' Running out of steam' in service either.
...

 

Re: 92219

I travelled on one of it's first main line trips around 1990/1 from Didcot to Derby & back. On the return it had major steaming problems & had to keep stopping for "blow ups".

 

Re: 92219

I take it you mean 71000, not 72010 which hasnt been built yet. The fact that it had the problems on the return but not on the way out suggests a poor fire does it not ?