Packard P40

Discussion in 'Aviation' started by rogerwilko, Jun 27, 2014.

  1. rogerwilko

    rogerwilko Member

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    Why didn't they fit the Mustang version Packard to the Curtiss P 40 F?
     
  2. GregP

    GregP Well-Known Member

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    Damned good question.

    I have heard it said by the designer's son in a speech at the Planes of Fame that they DID make ONE Merlin-powered, 2-stage airplane and that it performed VERY well at altitude ... but I can't find any supporting evidence of same, so I can't make the claim that it is correct in real life. Wish I could find evidence one way or the other ... but no joy so far.

    Not surprising if it never happened (nobody produces documents on what they didn't make), but is a bit annoying if it did really happen. I can't say either way to date, and make no such claim ... just passing on what I heard said in a speech. Hve done so before and still no evidence one way or the other ... might never be any.

    But since the P-40 airframe was designed with higher altitude combat in mind, it would be nice to see that least ONE example could really do it.

    Maybe in the future we'll know one way or the other ...
     
  3. rogerwilko

    rogerwilko Member

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    Never seeing either Packard version side by side maybe it was too much trouble to change the nose area?
     
  4. GregP

    GregP Well-Known Member

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    Nah, they moved the carburetor airscoop from top to bottom (downdraft versus updraft carb). Aside from that, it was all engine mount and hookup differences, whcih weren't too many once the engine mount was fitted.

    The P-40F was a small bit faster (maybe the scoop?) but the Merlin was a single-stage version, so they were really about equal. It needed the 2-stage engine to wake up mthe airframe at altitude.

    Wish I could find real evidence they DID it other than a verbal anecdote!
     
  5. tomo pauk

    tomo pauk Creator of Interesting Threads

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    In 1943, the production of 2-stage Packard Merlins was lagging a bit even for Mustang airframes. In 1944, P-40 was still a second best airframe, with no easy way to introduce the crucial thing - internal fuel tankage. Merlin Mustang was hauling around almost twice the internal fuel.
     
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  6. GregP

    GregP Well-Known Member

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    #6 GregP, Jun 27, 2014
    Last edited: Jun 27, 2014
    Not sure the P-40 was second-best. What if they fought at 8,500 feet, where the Allison was running very well? The P-40 certainly out-rolled the P-51.

    Might have been interesting ... but is an historic footnote in reality ...
     
  7. wuzak

    wuzak Well-Known Member

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    A version of the P-60 (the XP-60D) was powered by a V-1650-3.

    The P-60 was derived from the XP-53, the main difference was the choice of engine. The XP-53 was a P-40D fuselage with laminar flow wings and the IV-1430 V-12 engine.

    Curtiss was told that a fighter with laminar flow wings and the Merlin engine was require - this in late 1940, not long after the agreement for Packard to build Merlins under licence. The XP-60 first flew in September 1940 with a Merlin 28 (British built single stage engine), presumably because there weren't any V-1650-1s available for installation.

    A V-1650-3 was installed in the P-60 to create the P-60D - the A and B designations going to two turbo V-1710 versions, and the C to an R-2800 version. Presumably this was a pre-production or ealy production V-1650-3.

    No idea on the performance of the P-60D.

    The XP-60 was good for 387mph @ 22,000ft.

    Curtiss P-60
     
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  8. GregP

    GregP Well-Known Member

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    #8 GregP, Jun 27, 2014
    Last edited: Jun 27, 2014
    Wasn't a Merlin-powered P-40 though ... it was an entirely different beast.

    Had some P-40 in it, but not all that much.
     
  9. Shortround6

    Shortround6 Well-Known Member

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    The P-40 was a second rate airframe by the time the Packard Merlin V-1650-3 comes along ( 56 built in June of 1943. Double the number built up until then but a small fraction of what was built in Sept).

    The two stage Merlin was longer, heavier (around 150lbs) and required bigger radiators,intercooler radiators (over 300lbs more cooling system), oil coolers (30-40lbs?) and a heavier prop (110-70lbs depending on P-40). On the Mustang some of the weight went behind the CG, on the P-40????

    Unless you are really, really clever the P-40 is going to be 30-40mph slower than P-51 with the same engine at most altitudes. IF the planes are at roughly equal weight the P-51 should climb better, even if only a bit. The P-51 will have more range on the same fuel. Maybe only 10% but still?????
     
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  10. m37b1

    m37b1 Member

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    Performance most likely would have been similar to the V-1710-121 powered XP-40Q.
     
  11. GregP

    GregP Well-Known Member

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    The XP-40Q wasn't a bad performer at all and was more maneuverable and rolled better than the P-51. It was basically a cleaned-up P-40 and I think it would have been a good one. So, I'm not so sure the P-40 was a second-rate airframe at all, but I AM sure they elected to go in another direction in the real event.
     
  12. Shortround6

    Shortround6 Well-Known Member

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    In fact the XP-40Q sucked, it just didn't suck as bad as earlier P-40s.

    It needed more power to go slower than a P-51 while weighing less. The 422mph needed at least 1600hp if not more and 75in manifold pressure and 3200rpm and water injection. A P-51D could do about 416-418mph at the same height using just under 1300hp. Using a bit over 1400hp the Mustang could was good for 428mph? and the Mustang could go faster higher up and weighed 760lbs more. P-5D performance figures include a bomb rack under each wing. P-51D may be carrying 6 guns ( a 50% increase over the P-40Q) and more ammo.
     
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  13. GregP

    GregP Well-Known Member

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    Let's just say that I'm shocked at how badly we disagree on the XP-40Q, Shortround. Isn't that astounding?

    The performance curves are VERY good. It was 15 mph slower than the P-51D, which is nothing since p[lanes don;t fight at maximum speed except in very rare circumstances. If they do, it is mostly in a dive to catch or escape.

    But, no use for us to hash it out since it didn't make production and is a bit off-topic to boot. I wish it had been produced, but the jet handwriting was on the wall and the war was being won by existing designs, and I believe the arguments were covered in another thread anyway.

    You and I seem to have a very different view of airplanes of this era but that's OK. I'd still like to find proof that a 2-stage, Merlin-powered P-40 either was or was not built. At this time I'm leaning toward "no."

    Cheers.
     
  14. Balljoint

    Balljoint Member

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    I suspect the P-40 Merlin was destined for action over China/Burma. In the theater the IJA Oscars operated primarily at four digit altitudes. I’ve heard that the Allison P-40 was preferred by the pilots, though this could just be a preference for the old faithful version.
     
  15. Shortround6

    Shortround6 Well-Known Member

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    Planes may not fight at maximum speed but needing around 23% more power to go the same speed rather speaks to drag doesn't it?

    And drag affects climb rate, it affects range, it affects acceleration (in the higher speed ranges) and it affects the exit speed after a sustained turn or put another way, it affects the the speed at which a plane can turn without loosing height.

    The Performance charts are at WWII Aircraft Performance

    P-40Q could hit 407mph at 24,000ft using 3000rpm and 59.5in and over 1250hp (Military power) P-51D could hit 404mph (with bomb racks) at 25,000ft using 2700rpm and 46in (1025hp) Normal rated ( or max continuous power). or 428mph at 25,000ft using 3000rpm and 61in for 1285hp (Military power). P-51 was grossing 600lbs more.

    You can polish it any way you want but the P-40Q had a lot more drag than the P-51 and that won't go away. Using up two stage Merlins in a plane that was slower (and or shorter ranged for same fuel) while carrying less armament was hardly going to OK'd by anybody.
     
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  16. Shortround6

    Shortround6 Well-Known Member

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    The Actual P-40Fs and P-40Ls with single stage Merlins went to North Africa as it was known that the Allison powered P-40s were at a disadvantage against the German fighters, unfortunately by the time they show up in numbers the Germans are converting to the 109G.
     
  17. GregP

    GregP Well-Known Member

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    Well now Shortround, the speed I have is 422 mph at 20,500 feet. No two fighters of WWII had the same drag coefficient. Does that make them all inferior to the one with the lowest Cd? I'd have to say no to that one. The guys who flew the immprtals like the Spitfire and the Bf 109 might beg to differ, too.

    And I'm not "polishing" anything; it was what it was, Shortround. We disagree and that's OK. I don't want to rehash this in here. Go back and read the XP-40Q thread ... the arguments are there and I already stated that we all know they didn't buy it. The premise of this thread is that the author wondered why a 2-stage Merlin wasn't installed in the P-40. It certainly could have been and might have been, but was never proceeded with. The XP-40Q doesn't fit the thread's premise.

    Why don't you let it go? We'd just disagree ... and that insn't all that much fun these days. I very likely won't change your opinion and you certainly won't change mine, and we'd eventually likely not be nice about it ... and it's just opinions about an 80 year old airplane that really means nothing of import to anyone. I'd rather just let this one lie if that's OK with you.
     
  18. varsity07840

    varsity07840 Member

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    The performance difference between the 109F and early 109G used in North Africa was insignificant relative to the P-40F and L.
    the P-40F in short and long tail versions also saw action with the 13th AF in the Pacific.

    Duane
     
  19. wuzak

    wuzak Well-Known Member

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    The figures SR quoted were for "military" power. Could it be that the 422mph was with WEP?
     
  20. GregP

    GregP Well-Known Member

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    #20 GregP, Jun 27, 2014
    Last edited: Jun 28, 2014
    Could be. If quoting the 437 mph for the P-51, that was at max rattle, too. Might as well compare apples to apples.

    I hear the XP-40Q handled quite well and was more maneuverable than the P-51, but I'd have to suspect the opinion was subjective since it could only be rendered by what would amount to Curtiss factory pilots, who probably didn;t have a lot of time in P-51's anyway. The point I was trying to make is that the XP-40Q was a good-handling, decently fast plane that would have been a major step forward for all those P-40 pilots waiting for better performance. They never got to fly it and when they swapped P-40's for P-51's they got a winner in that bird, so they finally got their performance jump. Could have been P-40Q's, too, but wasn't.

    Everyone touts the performance of the Mosquito, but the XP-40Q was faster. It would have been a good new mount. Alas it is a "might have been," as were many other potentially good planes. I'mnot crying over it all these years later, but at least give the thing it's due credit. It definitely DID represent a pretty good performance upgrade over the P-40N. That would have been welcome, no matter where it came from.
     
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