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BR Standard class 6 No. 72010 'Hengist' and Clan Discussion Thread

Discussion in 'Steam Traction' started by Bulleid Pacific, Nov 23, 2009.

  1. 69530

    69530 New Member

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    Since the slow demise of the Edward Thompson thread which I found fascinating and informative, the continuous updates on 72010 Hengist are a breath of fresh air. For people like myself unable to contribute physically to loco building/maintenance (I live in France) the frequent updates are read avidly.
    Many many thanks to the gentlemen concerned everything from the large castings to smallest minutiae make essential reading.
    Good luck to your Project, we will see it in steam before long hopefully !!
     
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  2. huochemi

    huochemi Well-Known Member Friend

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    Is that drawing E 17316 on the NRM Southern Railway list?
     
  3. RLinkinS

    RLinkinS Member

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    Yes that is the number. It is for the lat 20 U class and the last 14 Ns. I do not know what differences there were compared to earlier locos

    Sent from my SM-A105FN using Tapatalk
     
  4. huochemi

    huochemi Well-Known Member Friend

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    Thank you. You never quite know what you are getting with the NRM's catalogue descriptions. The valve event tables on motion drawings are rather interesting. The Stephenson-geared Black 5 44767 has an immaculate set of cut-offs. The Duchess is pretty mediocre but they then do an average for the paired inside and outside cylinders which gives a pretty good result on that basis.
     
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  5. ianh1

    ianh1 Member

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    69530 - Many thanks! We should be publishing our decisions on the way forward with the boiler very soon.

    With regard to valve events, our reproduction of the Motion Arrangement drawing has the valve settings table on it.

    MotionEvents.jpg

    Fortunately we were able to get to the NRM before lockdown and took photos of the original drawing. We've transcribed the table data into an Excel spreadsheet

    Ian
     
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  6. huochemi

    huochemi Well-Known Member Friend

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    Thanks Ian. Could you post a larger image as the figures are difficult to read?
     
  7. ianh1

    ianh1 Member

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    I'd probably better not do that as the copyright of the drawing belongs to the NRM. Whenever I post a BR drawing I try to use a resolution that prevents the detail being read. All our drawings have been stamped with this

    copyright.JPG
     

    Attached Files:

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  8. clinker

    clinker New Member

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    Sorry to have dragged us back to here, but I'm having a bit of difficulty in getting My head around the outside admission, as there does not seem to be any form of balancing the pressure between the ends of the valve bores, so whearas the inside admission is in simple terms feeding a constant volume of steam into the cylinders , the outside admission appears to be 'compressing' the live steam, against boiler pressure, Am I missing something, and if so ,What?
     
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  9. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    Sorry to drag this off topic - but thank you for saying this. I really appreciate it. The thread has indeed "died" but I think that's because it has finally run its course, and many of us have achieved the level of debate and discussion the topic needed.

    Back on thread - and very much agreeing with you - excellent updates on a project of great interest, I have long felt the Clans were misunderstood and somewhat neglected in their history. Hopefully the next class member will go some way to prove a point on the original design.
     
  10. northernsteam

    northernsteam New Member

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    See the latest news (https://www.theclanproject.org/Clan_News.php) for another piece of gear which has been prepared earlier. The drivers toolbox/seat and pedestal are also made, complete with air brake and other bits, I have a photo with Matt Ellis working on them some while ago.
     
  11. northernsteam

    northernsteam New Member

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    Just received the latest 'Clan News'. Full of interesting info about the various avenues of progress being taken at present. Tender, boiler, driving wheels and motion, boiler and trailing truck, all in preparation for progress, in the right order of course. Superb photos of progress to the assembling a new loco., all in the 'Cathedral of Steam'. We just need to complete the front bogie and then it's the trailing truck and a rolling chassis is achieved.
     
  12. 'Clan' Hengist

    'Clan' Hengist New Member

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    I knew you would like the magazine.

    For those of you not currently members look for Steam Railway this coming weekend. There should be pictures of progress in there. Once that is out, look to our website. We will be posting an update on Saturday morning.

    Until then we are not posting the pictures in Clan News for the general public to see. Membership first, then our good friends at Steam Railway and the general railway community.

    The pics are worth waiting a little while for. Onwards and upwards. It's been a great last couple of months.
     
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  13. ianh1

    ianh1 Member

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    We're recruiting!

    Fund Raising

    The assembling of the main frames of 72010 Hengist is nearing completion; the Clan Project is now ready to step up a gear and start building the rest of the locomotive.

    We are looking to appoint a person who can lead a fundraising team. Ideally you will have some fundraising experience but we are always looking for motivated individuals who can help meet the Project's ultimate goal.

    You will join our Council of Management and also work closely with our Engineering Team to ensure that funding is aligned to the current locomotive build plan.

    Ideally you should have experience of Corporate Fundraising/Marketing. If you feel you could make a great contribution to our Project, please send a resume of your experience and contact details by email to Paul Waldron at finance@72010-hengist.org for a preliminary discussion on what is involved.
     
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  14. ianh1

    ianh1 Member

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    Over the last 6 months, we've been conducting an initial design review for the boiler for 72010. Recommendations have been submitted to the Council and these have been approved. The project will be building an all welded boiler, with a working pressure of 250 psi and a steel inner firebox. You can read about our reasoning here

    https://www.theclanproject.org/design/Clan_Boiler.php
     
  15. class8mikado

    class8mikado Well-Known Member

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    Think that welded steel is the way to go, and as a boiler redesign becomes inevitable then might as go the whole hog and have a steel firebox, 250psi spec etc The weight saving from weld might be offset by the required plate thickness ? . Also the firebox itself is going to be a tad smaller, ( longer stays ?) but again this is offset by the better steam raising anticipated by the Lempor. The area of concern that myself and others will likely have is that of increasing the Max. Piston thrust force by approx 10%. Compared to the Britannias, The Clans did not suffer wheels shifting on axles and were theoretically more surefooted than any other British Pacific but this increase is potentially undoing these virtues, bearing in mind that Clan centre driver axleboxes are smaller than on brits
    Perhaps an initially smaller cylinder ( liner) diameter needs to be employed...can always be opened up later.
     
  16. ianh1

    ianh1 Member

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    Thanks for the response. We have looked at the driving force as the centre driving axle on Class 7 has a bigger bearing. We've done calculations on it and believe that the projected bearing life is OK given the expected annual mileage. We have put a note in the design review about perhaps limited the number of rebores on the cylinder. A number of changes were made on the wheel seating following the wheel shifting episodes on Class 7 and these have been incorporated into the Class 6 drawings
     
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  17. std tank

    std tank Member

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    Yes, indeed, but it is not the smaller axleboxes on the main drivers that is the problem. It is the axle to wheel interface that is the problem if the power is increased. The axle diameter on the Clans is 9", whereas on the Britannias it is 10". Any increase in the power will probably have a catastrophic effect. The modifications to the axles on the Britannias did not stop the wheel movement on the axles. It started reoccurring after 5 or 6 years. We only have the figures on Bill Harvey's Brits at Norwich, so we don't know how widespread the wheel movement was.
     
  18. northernsteam

    northernsteam New Member

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    Very interesting debate.
    I am sure that all aspects of this will be assessed and re-assessed as time elapses before ordering. Certainly it does not sensible to limit the working pressure unless it is unsafe or impractical, however, just because the boiler will be safe at 250 does not mean that it has to run at that pressure.
    Is there a way of improving the wheel/axle interface to overcome that problem? Would there be a torsion problem re axle diameter being 1" less?
    I am sure that before the boiler design is approved it will be thoroughly checked over.
    We certainly don't want any incidents like 60532 at Durham, which was a crew problem, ending up as mechanical disaster!
    I have full confidence in the Engineering Team, check twice, think, check again, system. It certainly looks as if they have carefully considered many aspects already.
     
  19. Jamessquared

    Jamessquared Nat Pres stalwart

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    That article gives a good overview of the decision about riveted vs welded and copper vs steel construction. It also covers the materials and weight issues of an increase in pressure, in particular that when you translate from theoretical thickness to actually available platework, there is no difference from an increase in pressure.

    It is however entirely silent on a third factor, which is the impact of a higher pressure (and therefore higher potential TE and power outputs) on the mechanical structure of the locomotive. Were such factors considered as part of the decision making in increasing the working pressure?

    The unhappy experience of Flying Scotsman running with large cylinders and a 250psi boiler should surely serve as a cautionary tale, even if only to ensure that the mechanical factors are fully considered in the decision as well as the obvious constructional points of boiler design.

    Tom
     
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  20. class8mikado

    class8mikado Well-Known Member

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    Discussions about Clans will inevitably lead to the conclusion that they could and would steam - especially if jimmied. and the big load on a long hill test they would get up that hill... eventually.
    So given a decent steam raising boiler that delivers when its pushed, how best to get that bit of extra Grunt at the fully open 40% cut off climb - Higher pressure ? bigger cylinders ? bit of both? It is a fascinating quandry.
     
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