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Things that seemed a good idea at the time, but in practice are pretty useless.

本贴由 Eightpot2019-10-03 发布. 版块名称: Steam Traction

  1. 8126

    8126 Member

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    Not sure that's strictly true. Post-war, the big Bristol Centaurus radials were more successful in civil aircraft than the Rolls Royce V12s, precisely because the time between overhauls was greater (figures seem to vary, but <1000hrs for Merlins, and >2000hrs for Bristol radials). That there are still Merlins aplenty going now, and vanishingly few sleeve valve radials, I would attribute to the relatively conventional nature of the Merlin and its requirements, compared to the specialised and now highly unusual nature of a sleeve valve engine.

    None of that changes the fact that one of the most appealing advantages of the sleeve valve for IC engines (knock resistance) was completely absent in steam engine practice. It's also interesting that Paget's attempt was going to have single-acting cylinders, as with IC engines, which would definitely have made getting the lubrication right easier.
     
  2. paulhitch

    paulhitch Guest

    Sorry but this has nothing to do with "early Rolls-Royce car engines" which was the subject of your original posting. Sir Henry had been dead for around ten years before this particular unit, which seems never to have entered actual service, was brought out.
     
    Last edited by a moderator: 2019-10-11
  3. ross

    ross Well-Known Member

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  4. Spamcan81

    Spamcan81 Nat Pres stalwart

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    Indeed so but not all of them would have been Sumpies. An aircraft needed many different trades to keep it in the air.
     
  5. LesterBrown

    LesterBrown Member

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    But IIRC the problem with the uniflow Paget engine was with uneven thermal expansion because one end of the cylinder was hotter than the other leading to it seizing.
     
  6. jnc

    jnc Well-Known Member

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    The Merlin was used to power a lot of fairly iconic aircraft (Hurricanes, early Spitfires [the later ones used Griffons] , Mustangs [their Packards are US-built-Merlins], Mosquitos, Lancasters) and that surely has been an influence too.

    Noel
     
  7. RalphW

    RalphW Nat Pres stalwart Staff Member Administrator Friend

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    Maybe so but it illustrates that the sleeve valve was not the complete design failure alluded to by the OP who bought it up.
     
  8. Jimc

    Jimc Part of the furniture

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    There are a reasonable number of active Sea Furies with Centaurus engines. Given the high quality maintenance that the warbirds get its clear that the technology is more than viable in that environment. And I wouldn't disagree with the premise that very high performance poppet valve engines like the Merlin and Griffon require a similar level of capability in the shop.

    However we also know that much lower performance poppet valve diesel engines did not initially do well in the railway environment, and it took some time for things to improve. Its an interesting contrast between Maunsell's approach to the radical compression condensing Anderson principle with extended trials of a prototype, and Bulleid's rather bull at a gate approach with 5 ordered off the drawing board.
     
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  9. 8126

    8126 Member

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    I think that is a very concise illustration of the difference between two personalities, but also between their circumstances. Maunsell put Lord Nelson through extended trials as well before ordering more, something we would now consider an almost wholly conventional machine, and perhaps got fewer built as a result (thinking of the truncated third order). Bulleid, on the other hand, took an "Order enough and they'll have to use them," approach to forcing novelty on the unconvinced, which was fine when it worked...

    In the '20s and '30s Maunsell had time, but steadily reducing funds for serious investment in the fleet. Anything radical was going to have to be well proven before spending money on it. Whereas Bulleid was evidently quite successful in getting his projects funded, but seemed to know, particularly by the time Leader came around, that his time was running out. Whether or not nationalisation was in the wind, he turned 63 the year the war ended.
     
  10. Spamcan81

    Spamcan81 Nat Pres stalwart

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    The number of active Merlin engines still around is due to the number of surviving warbirds powered by them. If a similar number of Centaurus powered machines were discovered lurking in a cave, the warbird community would snap them up and the numerical superiority of the Merlin would not be as great.
     
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  11. Jamessquared

    Jamessquared Nat Pres stalwart

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    It's notable that in Holcroft, Maunsell had a technical assistant who was well suited to - and clearly enjoyed - the task of running extended experimental trials on locomotives. One of the striking things in Holcroft's book is how little he says about the period under Bulleid. (He left the SR in 1946, so before the Leader though by then the Q1s and both types of pacific had been introduced). I believe a lot of his time was taken up co-ordinating the SR workshop's response to the war effort, but it seems Bulleid was either unable or unwilling to use Holcroft in the same way that Maunsell was able. It's particularly interesting that in some ways, Bulleid's role on the LNER under Gresley was not dissimilar to Holcroft under Maunsell on the SR, but when Bulleid became CME, he didn't use, or recruit, a similar technical assistant to the same degree.

    I think your point about Bulleid increasingly being aware of the passing of time is well made. Maunsell was still in his mid 40s when he became CME at Ashford (following two years as CME at Inchicore); Gresley was in his mid 30s when he took over at Doncaster and still under 50 at the formation of the LNER, by which time he already had 12 years at the top of the GNR. By contrast, Bulleid was already 55 when he finally got his chance at "the top job", as it were.

    Tom
     
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  12. simon

    simon Resident of Nat Pres

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    At the time the ship was specified there were few if any known coal reserves in Australia - hence why the ship was specified to be capable of carrying them. If the coal reserves had been known about, there would have been no need to export coal Australia from the UK.
     
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  13. andrewtoplis

    andrewtoplis Well-Known Member

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    One of the first railways in New Zealand used extra wide wheels that ran on flat wooden track. The train was kept in place by guide wheels that acted on the inside edge of the 'rail'. Advantages were the cheapness of wood in New Zealand, disadvantages were that in the wet the engines slipped so badly the opening train had to be abandoned and passengers walked home after mud was walked onto the rails...

    It was soon converted...
     
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  14. Eightpot

    Eightpot Resident of Nat Pres Friend

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    Mr. Bulleid fitting the less than satisfactory LSWR steam reverser to his loco when he could have fitted the far better SE&CR type.
     
    Last edited: 2019-10-15
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  15. Jamessquared

    Jamessquared Nat Pres stalwart

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    We've been over that point numerous times, and it isn't true, though seems to have acquired urban myth status. The reverser fitted was an SR type, which had features derived form both the LSWR and Stirling (SE&CR) pattern reversers, but was not identical to either.

    Tom
     
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  16. Dunfanaghy Road

    Dunfanaghy Road Well-Known Member

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    Was this an example of 'Prosser's Patent Guide-wheel Railway'? I've just read about it in Dendy Marshall. Weird, even by the standards of the 1840's.
    Pat
     
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  17. LesterBrown

    LesterBrown Member

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    http://the-lothians.blogspot.com/2013/06/the-saga-of-southlands-wooden-railway.html?m=1
     
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  18. Jamessquared

    Jamessquared Nat Pres stalwart

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  19. andrewtoplis

    andrewtoplis Well-Known Member

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  20. Martin Perry

    Martin Perry Nat Pres stalwart Staff Member Moderator Friend

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    In Britain maybe; in the US, the EMD-powered locmotives worked pretty well from the outset.
     

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