P-47 Thunderbolt Armament

Discussion in 'Flight Test Data' started by Marshall_Stack, Jan 20, 2009.

  1. Marshall_Stack

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    The P-47 was notorious for having a poor climb rate (especially before water injection and paddle blades). Did anybody remove some of the .50 caliber machine guns to help lighten the load? I would think that somebody would have gone with just 6 .50 caliber machine guns to help the climb but I have not read of any accounts of pilots going with anything less than the standard 8 .50 caliber guns.
     
  2. Colin1

    Colin1 Active Member

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    You've remained largely generic
    so I've chosen something that was reasonably representative
    The P47-D22-RE weighed in at

    Empty 9,900lbs
    Gross 13,500lbs
    Max 15,500lbs

    I don't think shedding a couple of machine guns weighing around 90lbs each tops was going to make much difference to its climb rate.
     
  3. HoHun

    HoHun Active Member

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    Hi Marshall,

    >Did anybody remove some of the .50 caliber machine guns to help lighten the load?

    From a weight and balance chart I've seen, it appears that the 6 machine guns were considered "basic load" while the 2 extra were considered "alternate fixed gun installation". However, that doesn't mean they couldn't have been de facto standard.

    >I would think that somebody would have gone with just 6 .50 caliber machine guns to help the climb but I have not read of any accounts of pilots going with anything less than the standard 8 .50 caliber guns.

    Some ten years ago, someone on an internet forum mentioned the story of a squadron re-wiring the guns so that two of them could be cut out with the aid of a switch. This would leave an ammunition supply for emergency or for strafing on return from an escort mission. I thought this to be quite interesting, but have never found any more data on the issue than offered by the poster back then.

    Regards,

    Henning (HoHun)
     
  4. Colin1

    Colin1 Active Member

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    Hi Marshall
    I did just find this

    'Few pilots were anything but impressed by the Thunderbolt's firepower and the 8-gun armament remained virtually unchanged on all production models. In some combat units two guns were removed to reduce weight and enhance manoeuvrability, while in others where contact with the enemy was remote, only two guns were carried in each wing.'

    Not QUITE what you were looking for, shedding two guns would reduce the torsional moment on the wing but I'm not sure if that translates into better climb. Lighter clearly IS better but I'm not sure if the pilot would notice it that much in a plane with such a high combat weight.

    Sources
    Thunderbolt A documentary history of the Republic P47
    Roger Freeman
    MacDonald Jane's
    ISBN: 0 354 01166 9
    page 90
     
  5. Marshall_Stack

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    Removing 180 pounds is something, about the weight of another pilot.


    I think it was interesting what Curtiss tried to do with the P-40L. Reduce to 4 .50 caliber machine guns, smaller fuel tanks, and remove the starter. I wonder what the pilots thought of that last one. A starter couldn't weigh that much (40 pounds maybe?).
     
  6. Colin1

    Colin1 Active Member

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    This is quite interesting

    The early matching of the P47 against the Fw190 has already been related. Later models of the P47 saw many changes which vastly improved the performance of the aircraft.

    Relative data.
    1. Altitudes. Climb and acceleration tests were performed to 15,000ft. Other flying characteristics were checked in flights between sea level and 10,000ft.

    2. Aircraft employed. The airplanes used in the tests were a P47-D-4 with combat load and an Fw190 <doesn't mention model> with two loaded cannons and two loaded 30 cal machine guns firing through the propeller.
    The P47 was equipped with water injection. The Fw190 was in exceptional condition for a captured airplane and developed 42 inches manifold pressure on take-off.

    3. Pilots. The P47 pilot had 200 hours on P40s with 17 months of combat experience and had 5 hours on the P47 test aircraft.
    The Fw190 pilot had 300 hours on twins and 500 hours in single-engined planes but no combat experience. He also had 5 hours on the Focke-wulf test aircraft.

    Recorded Results
    1. Acceleration.
    i. 210 to 275mph at 2000ft, the Fw190 accelerated faster than the P47 and gained approx 200yds during the acceleration.
    ii. 210 to 275mph at 5000ft, same result.
    iii. 200mph to full power at 5000ft. The Fw190 accelerated faster than the P47 initially and gained about 200yds. At a speed of 330mph the P47 rapidly overtook the Fw190, gaining about 2000yds very quickly and was still accelerating. The P47 was using its water injection.
    iv. 220 to 300mph with full throttle at 15000ft. Same initial gain by the Fw190 of about 200yds but the P47 quickly overtook it. The Focke-wulf supercharger cut in automatically at this altitude and seemed to cut in at lower altitudes when a diving speed in excess of 340mph was attained.

    2. Climb.
    i. 2000 to 7000ft starting at 250mph. Both a/c were pulled up rapidly to the angle of maximum climb and held until an altitude of 8500ft was reached. The Fw190 climbed faster through the first 1500ft but the P47 quickly overtook it and steadily outclimbed it by 500ft/min. The P47 used its water injection and overheated slightly whilst the Fw190 did not overheat.
    ii. 10000 to 15000ft starting at 250mph. Once again the initial pull-away by the Fw190 through the first 1000ft however the P47 once again rapidly overtook and reached 15000ft whilst the Fw190 was still at 14500ft.

    It goes on to compare diving and turning but it's interesting that the P47 could actually climb - eventually. I think something could be made of the pilot choice for the Fw190 test aircraft and for that reason I also think that the mobility of the Focke-wulf in low-speed areas would be telling with an experienced Luftwaffe pilot.

    I had this impression that the P47 just climbed like a bus full of house bricks everywhere in its flight regime but it seems that is not the case, provided he kept his speed up, he'd whup the Fw190 in the climb.

    Sources
    P47 Thunderbolt at War
    William N Hess
    Ian Allan
    ISBN: 0 7110 0705 5
    page 46
     
  7. renrich

    renrich Active Member

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    I have read that some P47s had two guns removed in order to lighten the AC and that because of the enormous Ammo load it could carry( 475 rds per gun, I think) many times they took less than a full load. I believe that Bill may have mentioned somewhere that pilots in the P51D also lightened the AC by leaving two guns on the ground. Also in the Pacific although this had nothing to do with weight, I have read that some Corsair pilots, because the Corsair had gun switches for each gun and because the guns could be charged in the air, cut off two guns and used four until the ammo was gone from them and then switched to the two remaining.
     
  8. Marshall_Stack

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    A couple of quotes from "America's Hundred Thousand" by Francis Dean....

    " "One report indicated "Engine water injection and a paddle blade propeller gave the P-47 a vastly improved rate of climb, and allowed it to outclimb an FW-190 below 15,000 feet". "

    " "I was told if you tangle with an FW-190 or ME-109 at 25,000 feet and you want to beat him to 30,000 feet, then dive to 20,000 feet and zoom and you'll be waiting for him up there. It really was true; the Jug's zoom capabilities (out of a dive) were tremendous" "
     
  9. Colin1

    Colin1 Active Member

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    True
    it wasn't lost on me, that's a reasonable-sized guy and there'd be a difference although I wasn't sure given the power of the R2800 and the combat weight of the a/c that the two would miss such a comparative trifle significantly.

    Well, the P40 was heavy. If it's the same pre-war Allison engine powering it, I'd say a fair amount of difference. Unfortunately, the Merlin 28 was about 175lbs heavier than the Allison.
     
  10. TheMustangRider

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    Robert S. Johnson mentions in his book "Thunderbolt" that after he received his P-47D I think with the paddle blade propeller never again did a FW-190 get away by trying to climb.
     
  11. Marshall_Stack

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    He also mentions that when he went head to head with a Spitfire he lost in the climb until he got the paddle blades (with which he had reservations) and was able to eventually out climb the Spit. Hard to believe but it is what he said....
     
  12. KrazyKraut

    KrazyKraut Banned

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    I highly doubt that was a typical case unless the P-47 had a serious energy advantage. Also it would be interesting what Spitfire we are talking about. And I wonder if the Fw 190 in the report was the same Fw 190 A4 (1942) that was pitted against the P-38.
     
  13. Clay_Allison

    Clay_Allison Active Member

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    Depends on what model of spit.
     
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