No Merlin, what are the alternatives?

Discussion in 'Aviation' started by Ascent, May 10, 2013.

  1. Ascent

    Ascent Member

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    I sort of asked this question in another thread but I think it deserves a thread of its own.

    Given how ubiquitous the Merlin was what would have filled the gap if it hadn't been created?

    Was there anything else out there that had the development potential of the Merlin?

    Would it be another type filling all the roles or would you see a plethora of types on different airframes?

    The Merlin went into a lot of successful types, would they have been as successful with different engines?

    Thoughts please.
     
  2. Readie

    Readie Well-Known Member

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    The Merlin was without peer among aero engines and without it our war effort would have been a lot lot harder.
    Rolls Royce had the Griffon designed in 1938, this and the Vulture were put on hold while RR's resources were put into the Merlin.
    I would assume that the Griffon would have developed had the Merlin not existed as the Vulture's X was a flawed design.
    We also have the Napier Sabre H waiting in the wings too...

    Plenty of great British designs !
    Cheers
    John
     
  3. altsym

    altsym Member

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    Yep, the Allison.
     
  4. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Bristol Hercules?
     
  5. Juha

    Juha Well-Known Member

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    IMHO properly developed Hercules would have been too late for 39-40.

    Maybe Peregrine powered Vickers Venom instead of Hurricanes and Spitfires plus a fighter powered by a Mercury.

    Juha
     
  6. fastmongrel

    fastmongrel Well-Known Member

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    If the Merlin hadnt of been built Rolls Royce would have built something very similar. The Merlin was an evolutiontary development of a long line of RR designs stretching back to the Eagle in 1915. The only way to stop the Merlin or a very similar engine is if RR had got out of the aero engine business post WW1.

    RR in 98 years have only built one flawed engine the Vulture which had a poor design of crankshaft and it could have been made to work if time, manhours and money had been available. There was simply too much talent in the company and too much burning desire to build the best not to produce an engine in the Merlin class.
     
  7. nincomp

    nincomp Member

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    As a related question, which features of the Merlin gave it so much development potential?

    Note: Readie, I know that you want to reply: "Because it is British," but I hope that you can resist the temptation.
     
  8. Readie

    Readie Well-Known Member

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  9. fastmongrel

    fastmongrel Well-Known Member

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    Sir Stanley Hooker and his supercharger team. The Merlin was roughly equal compared to the DB 600 series or the Allison V1710 but the supercharger was what gave the Merlin the edge. Without Hooker you dont have the Merlin XX and 60 series.
     
  10. wuzak

    wuzak Well-Known Member

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    The Allison would have been too late to be useful (ie, not available in numbers befor BoB).

    Same can be said for Sabre and Vulture.
     
  11. wuzak

    wuzak Well-Known Member

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    The Vulture concept wasn't flawed, but its execution was.

    The crankshaft design wasn't at fault either.

    On issue was that the crancase halves weren't well secured, and would move relative to the other, causing main bearing failures. That was solved with locating dowels.

    Another was the cooling system design, where one of the pumps could end up cavitating and cause the engien to overheat. That was solved using a balance pipe between them.

    The big problem was the connecting rod design. There were breakages in the rod bolts, the original design didn't give enough clamping force and so the big end bearings failed. The second designe improved the situation, but not by much.

    Given the amount of time that Rolls-Royce needed to sort the Merlin the Vulture could have become a very effective powerplant. Alas, they did not have that time.

    There were improvements to be had - basically a 2000hp engine (Vulture IV/V) in 1940, running low boost and less than designed rpm. Imagine the remaining issues were sorted, it could run at the designed rpm of 3200rpm, or more, run the higher boosts possible with better fuel and a Hooker supercharger.
     
  12. wuzak

    wuzak Well-Known Member

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    I imagine if Rolls-Royce hadn't embarked on the P.V.12 they would have started the updated Kestrel sooner - and thus had the Peregrine a couple of years earlier. This might be the basis behind the Hurricane and Spitfire (the first go at a Spitfire, the Type 224, used a Goshawk - a Kestrel modified for evaporative cooling).

    Then again, an uprated Buzzard may be attractive.

    The Buzzard IIMS was rated at 955hp @ 2300rpm @ 2000ft (Lumsden). It's weight was 1540lbs (listed as 1140lb in Wiki, using Lumsden as a source).

    The width of the Buzzard was 30.6" (early Merlins 29.8", Griffon 30.3"), height 44.4" (Merlin 41.2", Griffon 46.0") and length 75.7" (Merlin 69.0", Griffon 72.0").

    If it was 1140lb, as per the Wiki page, it would be an attractive choice. At 1540lbs it would need more power.

    Enter the R. Beefed up to allo more boost and higher rpm (with special fuel) it was ultimately capable of 2900hp (1931), but with a poor TBO (about 1 hour!). A detuned version should give at least 1500hp, one would think. With a weight of 1640lbs that would be acceptable.

    The Width was up to 32.0", the height down to 42.0", but the length up to 100" - due to the size of the double sided superchager, inlet tranking (updraft carby, but the inlet was at the top and ducted to the bottom) and the extended nose case.

    After a few years they might come to the conclusion that there isn't much more stretch in that design, and begin the Griffon.
     
  13. Shortround6

    Shortround6 Well-Known Member

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    Buzzard was operating on 70-77 octane fuel. On the performance number scale, which is more linear than the octane scale;

    70 ON = 48.28 PN
    77 ON = 54.90 PN
    87 ON = 68.29 PN
    91 ON = 75,68 PN
    100 ON = 100 PN

    Just switching to 87 octane fuel would have made a big difference to the Buzzard if the internals would stand it.
     
  14. wuzak

    wuzak Well-Known Member

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    So, what do you reckon SR. A strengthened Buzzard would be capable of 1500-1600hp, or roughly 1hp/lb?
     
  15. buffnut453

    buffnut453 Well-Known Member

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    Sheesh...imagine the history books replete with references to how the Spitfire and Hurricane, both powered by that marvellous Buzzard engine, won the Battle of Britain. Somehow doesn't have the same ring as the magical Merlin. Then again, if the powers that be had stuck with the Shrew instead of choosting Spitfire, we'd have a Buzzard powered Shrew...which beggars the imagination!
     
  16. Shortround6

    Shortround6 Well-Known Member

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    If you can get a BMEP of about 180psi and run the Buzzard at 2700rpm you should get a bit over 1500hp. 170-180BMEP was do-able on 87 octane fuel. I am not so sure about the 2700rpm depending on year.
     
  17. wuzak

    wuzak Well-Known Member

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    180psi @ 2700rpm gives approximately 1375hp.

    I have the Merlin II at around 165psi BMEP. This would give the Buzzard around 1260hp @ 2700rpm.

    I think if the bottom end is beefed up like the R, and is running steel backed bearings (not sure that the Buzzard did), that 2700rpm is well within its capabilities. The R managed 3200rpm for racing, and 3400rpm in testing.
     
  18. Aozora

    Aozora Well-Known Member

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    One of the reasons Rolls-Royce developed the Merlin, starting in 1932, was a perceived need for an engine to replace the Kestrel with a capacity about halfway between the Kestrel (21.24 litres) and the Buzzard (36.7 litres), while using updated construction techniques. rolls-royce kestrel | rolls-royce merlin | 1942 | 0449 | Flight Archive

    The Griffon was developed at the request of the Navy using the experience gained from designing and building the Merlin, with further updates, such as fully enclosed oil passages, rather than external pipes. It used the same cylinder dimensions as the R and a refined version of the crankshaft. rolls-royce griffon | 1945 | 1852 | Flight Archive
     
  19. fastmongrel

    fastmongrel Well-Known Member

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    Whoops my bad I meant to say the Master conrod design was flawed but my stupid brain told my fingers to type it out as crankshaft :lol:

    I am completely with you on the Vulture being a near miss. One day I will get round to putting my ideas for an alternative history of the Boeing Washington with Vulture 100 engines and extended bomb bay dropping Grand Slams all over Europe and turning Hitlers concrete fantasies into rubble.
     
  20. wuzak

    wuzak Well-Known Member

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    Yeah...I still haven't finished mine!
     
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