Draughting arrangements for Bulleid Pacifics including the Giesl ejector

Given the price of coal it would be easy enough to look at the annual bill and move on from there. Break it down into consumption per locomotive, which are using the most per mile, etc
The development of locomotive exhaust systems is not over. We have moved on a long way from the trial and error, empirical approaches of the past. How many of our locomotives have an exhaust system that benefits from the best that the science can offer?
And if one were designed would we want to fit it? Few engines would be without visible change. Can a worthwhile improvement be achieved hidden away under the original design? Why change anything? Improved power output for a given fuel consumption is one incentive. Or the same power output using less fuel is the one the accountants want to hear.
Why pick on Bulleid Pacifics? Well there are significant numbers of WC/BofB in original condition and they are an obvious case for treatment since so much can be done with little being visible.
Is it worth making changes and improvements? At some levels no. But then there is that drive to find the solution to the unanswered, the ignored. To address the results of bad science and poor thinking. Worth making improvements? You bet it is!

 

Good morning Big Al,

Some excellent suggestions there, although, as you are probably aware, a few locos are fitted with some of the features that you mentioned, e.g. 34053 is fitted with ashpan sprays, authentic? I don't believe so. As for the exhaust modifications for a Bulleid as outlined by Mr Koopmans, this really isn't a big job, given the materials, any decent fab-shop could complete the components in a day, as for fitting, perhaps another day being generous, all well within the capabilities of most of the operating railways or main-line steam operators. All of the components are basically pipe of different diameters, although including a flare on the petticoat pipe would be the only complication.

Of course, it is doubtful if any of the Bulleids running on the Heritage Lines would be modified thus as it really isn't a screaming necessity, however, the potential for the ever growing main-line, er, squadron, of Bulleids could be the real beneficiaries of a "tune-up". 34064 amply demonstrated the validity of a front-end improvement back in the 60's, followed by 34092 in the 80's, is it time to take things to the next stage of development, very probably, yes. As for authenticity, what we talking about here are some relatively small changes to unseen components, anyone whinging about that would surely need to have their head-rivets counted!! As for the pay-back, well, several benefits have already been mentioned up-thread, but for me, the main issue is water consumption, anything that reduces the chance of that box on the back being used is a real bonus.

Cheers

Alan

 

Ashpan sprays are standard fittings on Bulleid Pacifics. Not so sure about the rebuilds though.

 

Thanks Ian.

Cheers

Alan

 

Indeed, testing of any mods would be a necessity. As for modifying Tangmere as per City of Wells, I ashamedly come over all platform-ender on that one, 34092 does sound superb!!

Cheers

Alan

 

Have had a chat with my colleagues regarding these suggested improvements and if those who propose them would like to sponsor 100% of the costs involved, as well as any reversion to original if no benefits are accrued, we will give them serious consideration.

 

Are you going main-line?

Cheers

Alan

 

Nope. We have insufficient funds to pay for the extra work needed for that.

 

The goal of any frontend improvement should not be increased draft but identical, sufficient, draft with less effort.
If someone has the details of the exhaust channel exit under the 5-orifice blastcap I could try and look
whether a new blastcap would do the trick with the Ell modified present chimney. It would be a pity if
the chimney with its integral blower ring could not be maintained. Note that the present chimney has an
exit area of 660 sq.in., the 9F Giesl had 352.8 sq.in and I suspect the CofW to have the same dimension.
Kind regards
Jos Koopmans

 

What might it cost? Can some/all of the existing components be modified or must new ones be made? (Actually, if you want the option to revert to the original design, better keep the old parts.) Can they be made by fabrication from stock sizes/shapes of metal, or are special castings required? How sensitive are the dimensions? Would the new components need to be capable of fine adjustment after fitting, to get exactly the right size/position or is it the case that 10mm either way won't make much odds?

Besides 92 Squadron, which light pacifics are currently under overhaul, or about to be withdrawn for overhaul? Which of those are either owned by, or closely associated with, the line where they are repaired? One springs to mind: 34007 Wadebridge. The MHR has a large share-holding in the loco company. So the people covering the cost of making and fitting a revised exhaust should be the people who benefit from any savings in fuel costs. However, I think it will be a few years yet before '007 re-emerges from Ropley works.

What about Blackmore Vale or "Archie" on the Bluebell?

Besides better coal consumption, a significant benefit of the Giesl exhaust on City of Wells is less drifting smoke and so better visibility for the crew. Jos - would your suggested changes to the Bulleid/Le Maitre exhaust have a similar effect, or is that due to some other property of the Giesl design?

 

No idea as to cost as nobody has said exactly what mods would be needed to fit in with Mr. Koopmans theory. The Giesl would be easier to price but I don't think Mr. Koopmans is thinking along those lines.

 

Regarding a new Giesl, unless a secondhand example could be obtained from somewhere (East-Germany, Austria)
it would be a very costly exercise as the blast cap is a casting with integral blower channels and the
possibility to adjust east orifice. As for the better view for the crew, because of the shape of the front of steam
locomotives there is an area around the chimney that has a lower pressure and has the tendency to hold to the
exhaust flow if the exit velocity from the chimney is too low.
Since the Giesl has just over half the exit area of the present Bulleid chimneys its exit velocity is better and the flow
from the chimney is not bothered by the low pressure area. I do not wish to sound pompous, but as insight in fluid
dynamics has been improved drastically in the last 70 years, I have this idea that I understand the front-end behaviour
different and better than Prof. Dr. A. Giesl-Gieslingen. This is just a matter of different generations, I can't really help that, and I admit at the same time that I just do not know it all. There is sufficient room for any eager student of fluid dynamics to add his part and I sincerely hope that they will do that. I have been in correspondence with both Giesl and Porta and both
stated that their chimneys were the end of it all, both cannot be right at the same time isn't it?
Regarding pricing of a new front end, let me specify the metal build-up:
-bottom flange on exhaust channels
- 4 to 6 side plates of blastpipe, unless it can be rolled in taper
- top plate, this lot to be welded together
- bolted blast cap carrying 5 or 7 exhaust tubes
chimney, outside on top of the smokebox to be retained
- smaller diameter size chimney
- new blower ring welded around it
- new inlet, trumpet mouth, my guess is that this can be made from standard tube bends
Given the levels of restauration engineering I have seen, it is well within the possibilities of any volunteer group.
As for the tolerances, 10 mm in height would not really matter, 10 mm offset from the chimney axis would greatly
matter and the exhaust tubes would be made too large anyway to allow for inserts. It is really a matter of sensible
engineering. Of course the redundant parts are retrofittable.
Reviewing this text it dawned on me that it could be engineered along Giesl lines, oblong chimney, linear blastcap
instead of an axisymmetrical execution, with some metal lying around we could have a lot of fun and a competent
pr officer could have his day!
I hope to have answered the earlier questions
Kind regards
Jos Koopmans

 

The odd thing is that when 34067 was in the works at Bury being restored for the late Mr Pickett, Rileys employed the Chief Engineer for 34092 specifically to oversee the work becuae of his extensive knowledge. Consideration of fitting 34067 like 34092 was made, but I do not know why it was decided to retain the original system in the end. There was certainly ample scope to fit a Giesl and astrong evidence from 34064 and 34092 to suggest it would be an enhancement. Other mods like air brakes were fitted so it cannot have been wanting to keep it "original". A missed opportunity IMHO.

 

I would say, almost undoubtedly, cost, Giesl were not the cheapest of ejectors to purchase.

 

If that would be the restoration that ended in 2003, my best guess is that Giesls were no longer available.
Schoeller Bleckmann is now in oilfield equipment, secondhand equipment would be rusted/eaten away and
reproduction may have given problems. Rumor has it that Giesl has a daughter that really sits heavy on his estate.
Kind regards
Jos Koopmans

 

Could you please help me out? The only info I have on the dimensions of the MN class is that in the book
by Mannion, page 160. Are the light pacifics identical? If so the front-end is rather indifferent for the
difference in evaporation area. That said, the BR8 appears to have a Kylchap with about 17.8 in. exit diams.
If so the combined area would be of a diameter of 25 in. while the MN has 29 in. Now, if someone dares
to fabricate a blastpipe with 7 properly positioned and inclined orifices of 3 in. each there is a good chance that
this will work properly in the chimney as given in the book.
Thanks in advance,
Jos Koopmans