What made the Merlin engine so great?

Discussion in '' started by TheMayor, Dec 21, 2009.

  1. TheMayor

    TheMayor Eight Time F1 World Champ
    Rossa Subscribed

    Feb 11, 2008
    Vegas baby
    A lot has been said that the P51 was only so-so with the Allison engine but when fitted with the Merlin, it's true personality came out.

    Does anyone know what it was about the Merlin TECHNICALLY that made it so good? Why was it so special in it's design, manufacture, or engineering that it could only be copied but not surpassed?

    I've always been curious...
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  3. ICEcap

    ICEcap Rookie

    Oct 19, 2008
  4. JCR

    JCR F1 Veteran
    Silver Subscribed

    Mar 14, 2005
    H-Town, Tejas
    It was the War Production Board and Army Air Corps the that did not allow Allison two stage two speed supercharger. The only aircraft to get them was the P-38. See here:

    Interestingly enough, Merlin engines never won Reno air races until someone figured out how to install Allison connecting rods.
  5. Gatorrari

    Gatorrari F1 World Champ
    Silver Subscribed

    Feb 27, 2004
    Full Name:
    Jim Pernikoff
    Actually, the P-38's Allisons were turbocharged, not supercharged, and that made all the difference. The P-38s sent to Britain lacked the turbos and were dogs as a result. To my knowledge, the Merlins were never turbocharged, because they didn't need to be; their superchargers were good enough for strong performance at altitude.

    Ironically, the same situation took place after the war in Unlimited hydroplane racing; the Allison ruled the roost until Merlins became plentiful; then the Allison crowd had to put turbochargers on their engines to remain competitive. Today the only piston-powered Unlimited running uses a turbocharged Allison.
  6. Bob Parks

    Bob Parks F1 Veteran

    Nov 29, 2003
    Full Name:
    Robert Parks
    The Merlin also had an unconvoluted (spl) intake and valves that didn't float. The intake which was more of an open chamber instead of a bunch of manifold pipe-type passages and it made full use of the two stage blower. No Allison has the sound of a Merlin.
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