P47D-11 vs. P47M

[EDO43]

  The Luftwafffe officially considered that their captured P-47D Razorback (with needle-tip prop!) generally much out-turned their (non MW-50) Me-109G-6 in flight tests. (On Special Missions: KG 200)

  Unlike with the P-51D, almost all of the 600 P-47 combat reports, on the Mike Williams "WWII Aircraft performance" site, show a very rapid gain in level turns by the early '44 P-47D on the Me-109G at all altitudes, even in left-hand climbing(!) spirals against gondola 109Gs, usually in less than four 360° turns from the merge...  This somewhat excepted turns to the right where the Razorback was still superior but MUCH slower gaining...

  The Bubbletop D was around 1000 lbs heavier than the Razorback, and turned slightly worse than even a P-51D Mustang.

   I doubt any of the later Bubbletop variants could match the early '44 Razorback turn performance in those combat accounts, but power and wing area could create an upset with the N maybe?

   It should be remembered that when the P-47D Bubbletop was being introduced, the P-47D was in the process of seeing a massive change of role, from escort fighter to ground-attack aircraft... The Bubbletop was essentially a ground-attack aircraft first and foremost, and everything about it was optimized for that role.

   Gaston

Tell that the the 56th Fighter Group w/ over 1000 e/a confirmed destroyed.  (yes, in the air and on the ground)

[Stoney]

It should be remembered that when the P-47D Bubbletop was being introduced, the P-47D was in the process of seeing a massive change of role, from escort fighter to ground-attack aircraft... The Bubbletop was essentially a ground-attack aircraft first and foremost, and everything about it was optimized for that role.

   Gaston

While its role was changing, the aircraft was still optimized for its original role--that of an interceptor.  Otherwise, they'd have gotten rid of the turbo and made it a pure supercharged plane.  The aircraft was not reconfigured in any way (from the late model razorback D-22/23) to make it more useful for ground attack.  In fact, the move to a bubble-top was made in order to increase the visibility of the pilot for air-to-air.  Also, the main increase in weight between the early D and later D's was increased fuel, and not structural weight.

[Gaston]

    -Could be true about the fuel weight. I think an issue could have been a modest change in CG. Judging from tests, there is no way the later Bubbletops could turn as well as the Razorbacks, but the reason for that could be aerodynamic, CG, keel area (a big difference!), typical weight, the lack of wing pylons, canopy drag, all combined to tip a non-linear balance.

      One of the things overlooked in simulations is that performance deterioration with weight, aerodynamics or CG is not something strictly linear, but a deterioration that probably occurs in a series of "steps". Thus one aircraft gains 300 lbs with very modest changes in performance, while another's performance takes a big drop from the same 300 extra pounds. What I mean is that performance changes are not predictable: I agree that the Razorback should NOT have a big edge on the Bubbletop in turning. We fully agree on that. In practice, it seems like there WAS a big difference: The Razorback out-turned EASILY the Me-109G-6, by the Luftwaffe's own account, which Me-109G-6 was very close, or marginally better at low speeds, than the P-51D, which was noticeably (10-15%+) better-turning than a P-47D Bubbletop... All this from actual tests, not my opinion...


     Quote: "While its role was changing, the aircraft was still optimized for its original role--that of an interceptor.  Otherwise, they'd have gotten rid of the turbo and made it a pure supercharged plane.  The aircraft was not reconfigured in any way (from the late model razorback D-22/23) to make it more useful for ground attack.  In fact, the move to a bubble-top was made in order to increase the visibility of the pilot for air-to-air."


     -They did the same thing to the Typhoon, which was stricktly a ground-attack aircraft. The Bubble canopy was incidental: You need it just as much, or more, when attacking low on the ground, to check for diving enemy fighters: Actually a more likely occurence than up at high altitude...

      They did indeed never re-configure the P-47, so the poor thing was lugging around a VW-Beetle sized turbocharger, with huge ducting, all of which was of absolutely no use to it for most European fighting after June of 1944...

      One Army high-ranking official put it in an amusing way: "We designed the P-47 for high altitude escort, and the P-51 for low-altitude ground-attack. Given how they both ended up serving, it's a wonder we won the war!!"

      Actually that huge turbocharger is one of the major reasons I don't like the later Bubble P-47Ds compared to the earlier Razorbacks: The aircraft had tremendous qualities that allowed it to be one of the best fighter-bomber of the war (except maybe for the Corsair's valuable dive-bombing ability?), and yet much of the superb engineering that was put into it was counter-productive to its later, most valuable role...

     It did break the Luftwaffe's back at the moment it was at its strongest, scoring 140 out of the 220 air-to-air kills of "Big Week", a period after which some US pilots said "the Luftwaffe was never the same". For the reliability of its guns alone I would, as a pilot, always have preferred it to the Merlin P-51, whose jamming tendencies in hard turns was never really fully cured (read the P-51 reports page on "WWII aircraft performance": Many Mustang kils were claimed with one gun, even on the D!).

     But as an efficient use of Power, energy and elegance in design, it certainly wasn't at the front row!

     Gaston
     

[bozon]

The bubble top replaced the razor back because the visibility was a greater advantage than what a few mph or dps give. Most real pilots flew with icons off and died to a plane other than the one they were looking at.

The turbo supercharger was never yanked out from the P47 because it was impossible. It practically required a new plane and not like it did any real harm. They managed just fine. See also: P-38.

The P47 was replaced by the P51 in the high alt role not because the P51 was a better fighter up there. Many would claim it wasn't. P51D could fly longer on less fuel and cost less than a P47. Simple logistics win wars. Anyway, by the time the P51D was running in full force it didn't really matter anyway who was flying up there, so it might as well be the cheaper ones. As a fighter bomber the P-47 had a clear advantage over the P-51. Fighter bombers do not dogfight that much, so the "bomber" part is more relevant than the performance advantages at low alt.