Hypothetical Combat - P-38L or P-47N

Discussion in 'Aviation' started by Magister, Feb 12, 2006.

  1. Magister

    Magister Member

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    Equal pilot skill - which one prevails?
     
  2. syscom3

    syscom3 Pacific Historian

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    P38L. It looks better.
     
  3. Jabberwocky

    Jabberwocky Active Member

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    Specifics please.

    Are we talking a high altitude, energy style engaement or a low down, drag out dogfight? Is it a one on one situation or a squadron vs squadron engagement?

    One -on- one, co-altitude, co-energy.

    Above 25,000 I'm taking the P-47. 20-25,000 feet its much of a muchness. Below about 18,000 I'd back the P-38.

    Squadron to group sized engagement:

    P-47 down to about 15,000, then they are about even. Its faster, has better dive, similar acceleration and better zoom. Minuses are worse turn and sustained climb. Firepower is about the same.

    P-47N suits a team on team engagment much better because its speed and altitude advantages allow it to dictate the terms of engagement.
     
  4. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    Good points Jabber! How about armament... 8 .50s vs 4 .50s + 1 20mm?!?
     
  5. syscom3

    syscom3 Pacific Historian

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    The centrally located four .50's on the P38 had no convergence issue's.

    Id say the P38 has the leg up over the P47.
     
  6. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    I'm with you Sys!!
     
  7. Jank

    Jank Member

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    The Thunderblt has a 50mph speed advntage and so can break away and re-engage at will on favorable terms
     
  8. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    At what altitudes?!?!
     
  9. Jank

    Jank Member

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    Lightning L

    360mph @ 5,000ft
    390mph @ 15,000ft
    414mph @ 25,000ft

    Thunderbolt N

    376mph @ 5,000ft
    425mph@ 15,000ft
    452mph@ 28,000ft
    467mph @ 32,000ft
     
  10. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    I doubt if this hypothetical battle would be above 25,000 feet - and although at say 15,000 feet the -47 has a 35 mph speed advantage over the -38, I doubt you're gonna see both aircraft "full out" so we better start comparing turn and roll rates....
     
  11. syscom3

    syscom3 Pacific Historian

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    I cant remember if the P38 had the contra rotating props. If it did, it could turn either way without concern for the prop torque effect.

    Did the P47N have dive brakes like the P38L?
     
  12. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    You're right about the P-38. I have a P-47 flight manual somewhere, I'll see what it says - I think there was provision to deploy flaps at certian combat configurations...
     
  13. Magister

    Magister Member

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    The P-47N had dive brakes.

    The P-47N had a climb rate of 2,950fpm at 5,000ft. (That's with full internal fuel of 570gallons!) With the fuel load of a "D" model, the N would have climbed very close to the M's climb rate which was 3,775fpm at 5,000ft.

    The only data I can find on the P-38L is that the climb to 20,000ft was 7 min. (average of 2,857fpm)

    Does anyone have reliable climb data for specific altitudes for the P-38L?
     
  14. Jabberwocky

    Jabberwocky Active Member

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    P-38J with V-1710-89 engines, rated at 1575 hp and 66 in. Hg at 10,000 feet.

    Altitude - RoC - Time - TAS Mph
    0 - 4000 - 0 - 160.0
    5000 - 3960 - 1.25 - 170.0
    10000 - 3820 - 2.54 - 183.5
    15000 - 3550 - 3.89 - 198.0
    20000 - 3190 - 5.37 - 214.0
    23400 - 2900 - 6.49 - 224.0**
    25000 - 2665 - 7.06 - 229.0
    30000 - 1830 - 9.32 - 243.5
    35000 - 980 - 12.99 - 259.0

    ** = Full throttle height.


    This isn't DIRECTLY applicable to a P-38L, but it's close.

    P-38Ls after the very first production examples had the V-1710-113 rated at 1600 hp WEP, or just an extra 25 horse power per engine than the P-38J. However, they could hold this power for longer periods and at higher altitudes than the V-1710-89s on the J model.

    P-38Ls were heavier and slightly draggier than Js because of extra equipment and the fitting of the dive brakes. Top speed was down about 6 mph, climb was slower down low, but better beyond 22,000 feet.

    Later in the war (mid to late 1944) the USAAF increased the engine rating up to 66" Hg with War Emergency Power, with British 150 octane in the ETO or 115/145 in the Pacific. Horsepower jumped by about 125 hp per engine, to around 1725 hp.

    Speed and climb were increased by about 5-10% over the P-38J. According to Lockheed test data at 66" Hg, top speed lept up to around 441 mph and climb was better than 4,400 fpm initially. 20,000 feet could be reached in about 5 and a quarter minutes.



    Getting good P-47N data is harder than nailing jelly to a wall, so I don't have anything solid.

    What I do have is some P-47D performance charts with the R-2800-95(W) and A-17 type turbosupercharger, rated at 70" Hg and 2,535 horsepower, which was introduced from late 1944. P-47 crews were notorious for pushing the big radials harder than the were supposed to. I have one report of a crew chief who pulled the stops on the turbosupercharger, allowing his pilot to push the R-2800 up to 90-100" Hg for about 30 seconds. This was an early D razorback, without water injection as well
    :shock:

    At 70" Hg, a P-47D-27 with a paddle bladed prop, would climb at 3,200 fpm off the deck and maintain that RoC all the way up to about 16,000 feet. After this, climb began to fall off.

    20,000 feet: 3,000 fpm
    24,000 feet: 2,550 fpm
    28,000 feet: 1,950 fpm
    32,000 feet: 1,400 fpm

    Top speed was 444 mph at 23,200 feet. Climb was about 5,00 fpm better than at 56" manifold, and speed was about 19 mph better at full throttle heights.

    The Jug was never one of the great climbers of the war . In fact, at war standard 56" manifold pressure and 2,300 hp you'd be hard pressed to find a comprable plane that was any slower in the vertical until that bloody great supercharger made itself felt around 28,000 feet.

    The P-47N had a R-2800-73 or -77, both with water injection, and both able to push out about 2,800-2,900 horses. The wing was redesigned and enlarged. The sape was refined slightly and the tips squared off, which increased agility and manouverability. Roll and turn performance were superior to the P-47D and M. It was quite a deal heavier than wither od the D or M though, with new wing, increased fuel, more equipment and strengthned undercarriage all adding up to i ncrease take off weight to over 20,000 lbs.

    Best climb for the P-47N is usually given as 2,700 fpm. However, given the increase in power and wing area, as well as performance, of the P-47N, this is probably for 'normal' power of 2,100 hp, not War Emergency Power of 2,800 hp or more. More than likely, performance would of been around or slightly better than that of a P-47D at 75" manfold pressure and 2,535 hp.
     
  15. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    Great Info - I'm seeing a slight climb advantage for the P-38 below 25,000 feet...
     
  16. syscom3

    syscom3 Pacific Historian

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    Im just wondering about the weight of the P47N.......... wouldnt that mass limit its initial roll rates, and once it was rolling, wouldnt it be harder to stop it?
     
  17. Twitch

    Twitch Member

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    Also why mix it up at 15,000 feet or less since there's no turbo-supercharger assistance for either plane?
     
  18. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
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    Why engage at higher altitudes when these aircraft engines will perform just fine. Although altitude is a desired commodity, you're still at an altitude were these aircraft are probably at their best if you consider all aspects of performance. You're supercharging an engine to gain performance at altitude, its at these altitudes where both aircraft's performance seem to start dropping off.

    If you "interpolate" the numbers Jabberwockey given for the P-38J, you'll find it best rate of climb is between 10 and 15,000 feet.

    Another aspect to look at is environmental. Although O2 will be used at altitudes over 12,000 feet, it still could be pretty uncomfortable fighting at altitude in an unpressurized aircraft above 15,000 feet. I've been in an unpressurized aircraft at 17,000, it was not comfortable!
     
  19. wmaxt

    wmaxt Active Member

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    I think I'll still take the P-38L esp over the Pacific.

    Fighter to fighter the P-47N had higher capacity Turbo above 30,000ft. I think it would have a power edge because of that extra capacity, which also gives it more energy to play with.

    There even from 20,000ft to 30,000ft, where the larger ailerons of the N give it an advantage against the L's better climb rate.

    Below 20,000ft Thw P-38L has the advantage in turn, climb, acceleration and is essentialy equal in dive and close enough in roll to counter anything the N can do.

    Dive rate at high altitudes is definately in the Ns favor for the bounce or escape, though the P-38 was also a good diver with control. The P-38 wasn't as fast in the dive but the persuing aircraft has the advantage of "cutting the corner" as the other aitcraft pulls out. Plus the P-38 has effective fire to 1,000yrds.

    Speed difference isn't that great, as an escape the relatively slow accelerating P-47 has to clear 1,000yrds before he's clear. The P-47 isn't fast enough to circle for a rengagement from the rear. The P-47 can turn it into a head on attack but then he faces the P-38s guns at least 200 to 500 yards before he in effective gun range. A P-38s zoom climb is better so thats out.

    wmaxt
     
  20. MP-Willow

    MP-Willow Member

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    I think both are a great match. Now I am gessing this is in the PTO and over water. The P-38L will turn a little better, but the P-47N will have the better power I think. Also in this fight the P-47 will take better damage. P-38s have two engines so twice the concern.

    If you have a group, the P-38 might have the edge, but would need to use lots of space. ;)
     
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