A naval version for Warhawk?

Discussion in 'Aviation' started by pampa14, Jul 18, 2015.

  1. pampa14

    pampa14 Active Member

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    I share with you some pictures of fighters Curtiss P-40 operating aboard aircraft carriers or on the flight deck. Some questions for aviation and history enthusiasts of WW2. There was a naval version of the P-40? Which countries have used during the war and which Operating Theatres? To view photos visit the link below:


    Aviação em Floripa: Curtiss P-40 em Porta-Aviões


    Best Regards.
     
  2. gjs238

    gjs238 Well-Known Member

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  3. GrauGeist

    GrauGeist Well-Known Member

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    These photos of the P-40 aboard carriers show the P-40 being transported to various theaters (PTO, MTO, etc.) and were never navalized for U.S. Navy service.

    Because of the great distances involved, the U.S. Army Airforce relied on the U.S. Navy to transport their aircraft to destinations across the globe. This is why you'll see photos of P-47s, P-39s, P-38s and other land-based aircraft that lacked a long-distance ferry range, lining the decks of carriers.
     
  4. RCAFson

    RCAFson Well-Known Member

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    There was a call from the USN to investigate the P40F for carrier suitability:

    But the P40's small wing makes it unsuitable for carrier ops.
     
  5. kool kitty89

    kool kitty89 Well-Known Member

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    I believe it was Shortround06 who noted the relatively high ground pressure on the P-40's landing gear was a major consideration for foregoing major consideration in carrier use even back with the lighter P-36.
     
  6. GrauGeist

    GrauGeist Well-Known Member

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    In 1938, the USN did, in fact, look at the P-36 as a candidate for Naval service.

    I don't have the details on hand at the moment, but it shouldn't be hard to find.

    There were 4 proposals and the requirements included several different combinations of armament (i.e.: 2x.30/2x.50, 2x.30/2 cannon, etc.) and various radial configurations. It may be interesting to note that the F4F and the P-36C were very close in weights, the P-40 being much heavier.
     
  7. gjs238

    gjs238 Well-Known Member

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    Marines flying P-40's is an interesting concept though.
     
  8. Shortround6

    Shortround6 Well-Known Member

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    Trouble is the call was for P-40Fs. The Vast majority of those went to North Africa.

    Another problem is simply getting them off the flight deck in any condition to go into combat. We can worry about landing later. :)

    A F4F-3 with 4 guns, 1800 rounds of ammo (?) and a pair of drop tanks was supposed to need 736ft of take-off run with no head wind and 330ft of take-off run with a 25 knot head wind.
    A P-40F at 8500lbs (no drop tank, front wing tank empty= 110 gallons of fuel and 1410rounds of ammo) was supposed to need 1550ft of take-off run with no head wind and 550ft of take-off run with a 35 knot head wind.

    P-40F could go 9100lbs with full internal tanks and a drop tank and over 9300lbs with a 500lb bomb instead of the drop tank.

    If you can get the weight down to 7500lbs it only needed 360ft with a 35kt head wind. However you were starting with a plane that weighed 7027lbs with guns but without pilot, oil, fuel or ammo.

    Figures for the P-40F are from the pilots manual. Perhaps with different flap settings it could do a bit better or by trading altitude for airspeed after leaving the front edge of the deck (always a bit tricky and requiring careful timing on a heaving deck in less than perfect weather).
     
  9. GrauGeist

    GrauGeist Well-Known Member

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    Another problem for the P-40 is it can't idle very long without an overheat condition, so if it were to be used in carrier ops, the waiting aircraft at the end of the launch sequence would be starting to get critical temps unless they could move the que fast enough.

    The prospect of a navalized P-36C is actually kind of a neat idea, to be honest.
     
  10. kool kitty89

    kool kitty89 Well-Known Member

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    The P-40F would be one of the worst in that case ... one of the heaviest P-40 models around. P-36 derivatives seem much more compelling on the whole.

    USN tests were consistently substantially lower than Grumman test figures for take-off. I believe different standards were used (no mention of clearing obstacles in the Navy tests, so possibly more a concern of 'distance to get off the deck' given the obstacle issue is more relevant for land-based operations).

    F4F Performance Trials

    For the F4F-3
    Take-off distance in a 25-knot wind 171ft (6260 lb gross weight) and 194 ft (7065 lbs)

    The F4F-4 at 7369 lbs gross required 215 ft in a 25 kt headwind. (using full-span duplex flaps)

    The standard F4F-4 at 7426 lbs could take off in 256 ft in a 25 kt headwind (605 ft no headwind) or at 7972 lbs took 310 ft (710 ft).


    In any case, the P-40F still wouldn't be a good option at all. The lighter P-40B or C might have been somewhat attractive or the later lightened P-40N, but R-1830 powered versions aimed at being lighter seem more likely to be realistic options.


    P-36 with the Wildcat/Martlet's engines (including the single-stage ones) should have performed better than the similarly powered Wildcat/Martlet, though without the P-40D's wing, you'd be limited to the P-40B's armament at most (not sure if dropping to .30s in the cowl would be better or not given the weight and RoF trade-offs -American .30s do pack more of a punch than .303s so 6x .30s wouldn't be too far off from 8x .303s in firepower, and ammo capacity would likely be higher than what the Spit/Hurricane carried). The USN was pushing hard for cannons, though and the P-40D's wing (with provisions for hispanos -unused in USAAF and RAF service) might be a compelling consideration. (M1 Hispano reliability would pretty well nix practical chances of service, though)
     
  11. GrauGeist

    GrauGeist Well-Known Member

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    The 23mm Madson cannon was fitted to the P-36A, but caused a performance penalty.

    However, that right there, proved it could be done. As far as additional armament, the P-36C did have additional .30 MG in each wing, but required an external ammo tray.

    While people tend to turn up their nose at the .30 MG, against Japanese fighters of the day, it was suitable enough to cause severe damage.
     
    • Bacon Bacon x 1
  12. kool kitty89

    kool kitty89 Well-Known Member

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    #12 kool kitty89, Jul 21, 2015
    Last edited: Jul 21, 2015
    Several export Hawk 75 models had 4-gun wings similar to the P-40B and C, so it shouldn't have been a problem. (puting .50s in the wings would wait until the redesign used with the P-40D) Different combinations of .50 and .30 caliber guns were used in the nose. (or 7.5 mm or .303 )

    I'm not sure those were external ammunition boxes on the P-36C, but possibly spent cartridge case retainer boxes rather than using open-ended case ejection chutes. (concerns over cost/shortages of brass? I'd think this would make more sense for training units than operational ones)

    Indeed, and again, those .30-06 rounds pack a bit more punch than the RAF's .303s so those 6 to the British fighter's 8 isn't too bad even with 2 synchronized. Going with .50s in the nose is still more firepower but down to only about 500-550 RPM and a couple hundred pounds added weight depending on ammunition loads used.

    Bombers would be where the lighter armaments would hit more trouble anyway, that went for British fighters too.
     
  13. Shortround6

    Shortround6 Well-Known Member

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    The early P-36s had trouble landing on concrete and grass. The landing loads (impacts) causing wrinkling and buckling of the wings in the area of the landing gear attachment points which called for heavier skinning and braces.

    Everybody wants the light weight of the early P-36 but then wants to add guns, armor, self sealing tanks, more radios, beefed up structure (which is supposed to magically add no weight) heavier engines (with bigger props?),etc.

    Curtiss's own advertising brochure for the Hawk 75

    http://www.ww2aircraft.net/forum/at...upload-curtiss_hawk_75-a_pursuit_airplane.pdf

    lists an ultimate "G" load factor of 12 for the Cyclone powered 9 model and an ultimate "G" load factor of 11.5 for the Twin Wasp powered model. It does say that the Twin Wasp aircraft can be delivered with a 12 "G" load factor at an additional cost and weight.

    So lets throw in 220-240lbs worth of guns/ammo (four .30s with 500rpg) , 90lbs of armor/BP glass, 250lbs worth of tank sealing, another 60-80lbs for a two speed R-1830 engine and see what happens to the "G" load factor. It might be down to 10.5 or so. Landing G load factor goes down too. US might require beefing up of structure to raise the load factors? BTW this is with 105 US gallons of fuel.
     
  14. GrauGeist

    GrauGeist Well-Known Member

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    #14 GrauGeist, Jul 21, 2015
    Last edited: Jul 21, 2015
    The external boxes on the P-36C were indeed ammunition stores for the additional MG. The spent casings fell away via a discharge chute as is the case with most fighter aircraft.

    Retaining the original AN/M2 .30 in the cowl and wings, plus an additional pair of .30 MGs - one to each wing, would certainly provide adequate firepower for the adversaries it was facing at that point in the war (PTO, of course).

    The F4F-3 proved it could be dangerous to the Japanese, armed with only 4 .50 MG (look at Lt. O'Hare's success against 5 G4Ms as an example), so then one may consider this option, but again upping from .30 to .50 comes with additional weight (both in the .50's physical weight and that of the ammunition).

    But I would say that the choice would either be 6x.30 MG or 4x.50 MG as a max armament option. Anything beyond that is working against the P-36's attributes and you may as well look to another current aircraft or build a new from scratch.
     
  15. kool kitty89

    kool kitty89 Well-Known Member

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    #15 kool kitty89, Jul 22, 2015
    Last edited: Jul 22, 2015
    I was expecting modifications similar to what the P-40B and C received, hopefully saving a modest amount of weight due to the differing engine and possibly due to swapping the nose mounted .50s for .30s. (the P-40D had weight gains due to expanded fuel tankage, heavier engine, larger radiator and oil coolers, and the redesigned wing -I assume some structural strengthening as well- so I'm not sure how applying just the new wing to the radial engined counterpart would compare) The single stage R-1830 would also be lighter than the 2-stage one, but obviously poorer performing above ~14,000 ft. (the 2-stage would be the one to go with)

    7500 lb take-off weight seems realistic with P-40C style fittings, possibly a bit less. With the lighter P-40B configuration (and more primitive self sealing tanks) it might get close to 7000 lbs gross, especially with the fuselage guns swapped to .30s.


    That said, the landing gear structural issues would remain the main concern and the one I first pointed out. (admittedly due to you explaining such in previous discussion)

    Of course, the F4F and F2A had landing gear issues of their own.


    Admittedly, this is less of an upgraded 'normal' P-36, and more a radial engined, navalized P-40.


    The French Hawk 75s were, again, already mounting 2 guns in each wing similar to the P-40B and C and the naval fighter we're considering would be in the same timeframe as the Tomahawk anyway, so the same armament options would apply: up to 2 .30 caliber machine guns in each wing and 2 .30 or .50 caliber guns in the upper nose. With the weight and poor synchronized RoF of the .50s, .30s in the nose seem fairly attractive (I believe they could still manage around 1000 RPM when synchronized, double what the .50s managed, at least with long ammo belts adding a bit of drag -best case might be closer 550 maybe 600 RPM).

    If the wings could carry .50s, then one in each wing and 2 .30s in the nose would make sense (some British Buffalos were modified to such too ... maybe F2A-3s should have done that to save weight), but with the existing Tomahawk style wing, the 4 .30s seems the most likely limit.

    Fleet Air Arm export models (in leu of the Martlet) might prefer keeping the nose mounted .50s given the better protected aircraft in the ETO.


    I also forgot to comment on the Madsen cannon earlier. The P-36 test aircraft used it in underwing gondolas, this would not be the case for the cannon mounts in the P-40D wing. The 23 mm belt-fed madsen cannon was also fairly similar in size and weight as the hispano but around half the rate of fire. I don't think the US secured any sort of license for it either, so short of reverse engineering, it would be a no go. (it might have been more reliable than the American hispano though, and belt fed from the start, but probably a better fit on the P-38 and especially P-39 than in the P-40's wings)
     
  16. GrauGeist

    GrauGeist Well-Known Member

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    If it were my decision, I would go with the 6x.30 for the simple fact that the convergence as well as the centerline fire would provide a formidible amount of hurt downrange. I know this isn't providing the "wow" factor that the later aircraft had with their 6 or 8 .50 setups, but this is early war and the lack of armor on Japanese aircraft can be exploited.

    Having only 4 MGs (2x.30/2x.50) brings to mind the shortcomings of the Italian aircraft. Wonderful machines but nearly harmless to an adversary.
     
  17. GregP

    GregP Well-Known Member

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    #17 GregP, Jul 22, 2015
    Last edited: Jul 22, 2015
    I think the P-40 could have been lightened quite a bit. The weight savings would not be in areas normally associated with US Naval aircraft, but it could have been done. The P-36 could have been strgthened a bit.

    I have been in a P-40 (back seat) that got absolutely planted on the runway with no damage and no hint of an issue. I'm pretty sure the GEAR could handle it ... the issue is whether or not the plane could be made signinficantly lighter and STILL handle it.

    Can't say myself, but I believe it could have been done if the need was great and the decision to try was made. There's a lot of beef in a P-40. We have one and it is nothing if not strong. It passed a pretty good dive test.

    Since it wasn't a dive bomber and wasn't going to be, the extra heft wasn't strictly needed. It could have been accepted with less than the required structural stength at the time.

    I have no idea of the magnitude of the weight reduction program, had they done it, but I KNOW the eventual plane could have been made on the same equipment since all they would do is to reduce the mass. There would be no exrta dumensional capacity needed.

    I'm pretty sure it could have been lightened considerably if the ultimate G-load had been reduced to something like 9 - 10 ... and the P-40 never had the excess power to sustain that level anyway.

    Another possibility would be to strengthen the P-36 and do a serious streamlining program to increase speed. The only issue would be the engine. I don't know if the R-2600 would have been possible, but I'm sort of doubting it. Perhaps an earlier R-2000? Or a new R-2300 or thereabouts ... a new engine would be fraught with delays. An earlier R-2000 maybe not ...
     
  18. RCAFson

    RCAFson Well-Known Member

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    #18 RCAFson, Jul 22, 2015
    Last edited: Jul 22, 2015
    I understand the USN wanting a "P40F or comparable type" since at that point they wanted an aircraft with superior climb, and speed performance over the rather anemic F4F-4, but using a navalized radial engined P40 variant just gets them back into the same boat they were trying to get out of.
     
  19. GrauGeist

    GrauGeist Well-Known Member

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    The P-36 wasn't a "navalized P-40 type"...the P-40 is actually a water-cooled version of the P-36.

    When the Navy was looking at the P-36 (1938), the P-40 prototype had just taken flight for the first time.

    Also, both the F2A and the F4F-3 had not yet entered service at the time of the USN's inquiry, so there was no way to compare or judge the P-40, F2A and F4F-3, as their qualities and performance were not yet established.

    So at the time, the P-36 was the hottest thing going.
     
  20. T Bolt

    T Bolt Well-Known Member

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    I doubt that a navalized P-40 would have been considered. The navy seemed to have a very strong prejudice against water cooled engines. Maybe one if the experimental radial engine upgrades to the P-40 Curtiss kept coming up with throughout the was?
     
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