WI: USAAF adopts F4U Corsair or F6F Hellcat for long range bomber escort missions?

Lets say for the sake of this scenario, the USAAF decides to give USN fighters a try for long range bomber escort missions over Western Europe. How do/would the premier USN fighters compare to their Luftwaffe counterparts and contemporaries? How does the air war over Western Europe change, if at all?
 
Both a bit lacking for the B-17 for the desired altitude.

But otherwise, FAA Hellcats did alright the few times they came up against Axis fighters.

F4Us would massacre FW-190s.
 
Most air combat in the Pacific took place at lower altitudes than in Europe. The P-47 used the same engine as the F6F and F4U but was also equipped with a turbocharger which improved its altitude performance. That was also the problem with Allison engined Mustangs. The Allison engine had only a single stage supercharger which did not handle high altitudes well. The Merlin with a two stage supercharger handled high altitudes better.

I also believe that the F4U and F6F did not have the range that the P-51 had so would be more limited on their role than the Mustang was but their range could probably be improved with the use of larger droptanks and/or more 'wet' connections in underwing pylons.
 
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I also believe that the F4U and F6F did not have the range that the P-51 had so would be more limited on their role than the Mustang was but their range could probably be improved with the use of larger droptanks and/or more 'wet' connections in underwing pylons.
This is the salient point - short range of F6Fs and most of F4Us. They carried, in most of the cases, less fuel internally than P-47, and R-2800 was not a frugal machine, especially once it was asked to provide those 1500-2000 HP at 25000 ft.
The F6F also offered no performance advantage over Fw 190 or Bf 109 of the era.

Now, about what-ifs. Do not delete wing tanks on the F4U but make them self-sealing like on the F2G (= 309 US gals internal tankage), add two drop tanks of 110-150 US gals and there is a 400-450 mile combat radius under USAAF requirement that included fast cruise of 310 mph at 25000 ft and 20 min combat. For extra range/radius, have extra fuel tanks installed under the pilot, like it was proposed for a 2-seat F4U.
 
Why not simply build more P-47s for Europe? The USN needs their Hellcats and Corsairs which were more then perfectly adequate against the Japanese airforces.
 
This is the salient point - short range of F6Fs and most of F4Us. They carried, in most of the cases, less fuel internally than P-47, and R-2800 was not a frugal machine, especially once it was asked to provide those 1500-2000 HP at 25000 ft.
Internal fuel capacity was 237 gallons, and a pair on unarmored ferry tanks in the wings for 62 gallons each, and/or two 154 gallon drop tanks could be carried, for a range of 1300 nautical miles@180kt, for drop tank and no ferry
London to Berlin is under 600 miles. 83 gallons an hour normal cruise at 10k, 93 at 20k, 42 gallons for economy cruise, with 570HP@1500rpm
290gallons/hr at Full Power

P-51 269 Gallons
 
Huh, I was under the illusion that the USN planes usually had long ranges, especially when fighting in the Pacific over vast distances.
There was a big difference in cruise requirements, Pacific vs. German-held Europe. USAAF required cruising at 210 mph indicated air speed (= about 310 mph true air speed) at 25000 ft, drop tanks, combat of 20 min at highest permissible speed, return to base at, again, 210 mph IAS and 25000 ft, 30 min allowance to land. USN requirements were far easier - like cruise at 15000 ft at auto-lean mixture, and return to carrier at 1500 (1.5 thousand feet) at 170 kt TAS (= 196 mph TAS) after combat. Cruising over Europe at 15000 ft will get the Allied fighter killed by either 88mm or LW fighter, and at 1500 ft and 200 mph even the MG 34 stands chance. Note here that F6F-3 has, even under such conditions, just a 355 mile radius (250 + 150 gals fuel) - the P-47 can better that with 305+110 gals under more strict USAAF conditions.
BTW - same reasoning was for Zero's range/radius: yes, it will fly far & wide if that flight is done at 200 mph.
 
Internal fuel capacity was 237 gallons, and a pair on unarmored ferry tanks in the wings for 62 gallons each, and/or two 154 gallon drop tanks could be carried, for a range of 1300 nautical miles@180kt, for drop tank and no ferry
London to Berlin is under 600 miles. 83 gallons an hour normal cruise at 10k, 93 at 20k, 42 gallons for economy cruise, with 570HP@1500rpm
290gallons/hr at Full Power

P-51 269 Gallons
Do we want to have non-self-sealing tanks containing the fuel when entering an air combat?
About the power settings - flying a Corsair with 570 HP will mean speeds of perhaps 200 mph? An easy way to enable LW fighter jocks to rack up the score.
P-51B-K with 269 gals of internal fuel yet has to strap on the drop tanks, and enjoy the 50+% greater mileage than what R-2800 was offering.
 
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Do we want to have non-self-sealing tanks containing the fuel when entering an air combat?
used first, before drop tanks
About the power settings - flying a Corsair with 570 HP will mean speeds of perhaps 200 mph? An easy way to enable LW fighter jocks to rack up the score.
P-51B-K with 269 gals of internal fuel yet has to strap on the drop tanks, and enjoy the 50+% greater mileage than what R-2800 was offering.
B-24 cruise was 180mph. Stick with the Bombers unti fighters are sighted. F4U has far better climb and acceleration than the P-47 at the
bomber altitudes
P-47 was using 100 gallons/hr, so the F4U would have better range than that, but not as much as the P-51. Few things did
 
Here's a video discussing turbochargers vs superchargers in WWII and it has a direct comparison of the Corsair vs P-47. There was a massive power advantage for the P-47 at all altitudes above about 3,000ft. At 30,000ft, the P-47 is 60mph faster the the F4U. The whole video is interesting but you can skip to 36:01 for the graphic representation comparing the two planes.

 
used first, before drop tanks
Okay, so we have 237 gals of fuel before entering the combat. This is not very different than what the razorback P-47 will got after it used the 60+- of it's 305 gal internal tank for warm up and take off to a safe altitude so it can switch to belly drop tank (110 gal British type was probably the best what it gotten in Europe in Autumn of 1943).
Such P-47 was rated for 375 mile escort radius. I don't think that F4U will get more than 5% more, 400 mile radius is probably stretching it.
OTOH, the F4U with additional internal self-sealing fuel tanks (not hard to do, just wasn't done apart from token number of F2Gs) would've been a fine long range escort.

B-24 cruise was 180mph. Stick with the Bombers unti fighters are sighted. F4U has far better climb and acceleration than the P-47 at the
bomber altitudes
P-47 was using 100 gallons/hr, so the F4U would have better range than that, but not as much as the P-51. Few things did
Fighters were required by USAAF to cruise at 310 mph (more precise, 210 mph indicated at 25000 ft) when escorting, so the LW has hard time trying to bounce them. Facsimiles of two tables describing the escort requirements are in the closing pages of the 'America's hundred thousands' book.
In order not to run from the bombers, fighters weaved above and in front of the bombers after rendezvous, so even book radius figures were true just for instances where relaying was used.
F4U might as well have better climb and acceleration than P-47 under 20000 ft, but above 25000 ft it was not so. P-47 was faster there by 20+ mph, the performance margin above Fw 190s being such that LW pilots were returning back after spotting the Jugs.
 
used first, before drop tanks
No! Drop tanks are used first so you can drop them when you encounter enemy. Very often the Germans would send a first wave of fighters up early just to get the escort to drop fuel tanks early.

B-24 cruise was 180mph. Stick with the Bombers unti fighters are sighted. F4U has far better climb and acceleration than the P-47 at the
bomber altitudes
P-47 was using 100 gallons/hr, so the F4U would have better range than that, but not as much as the P-51. Few things did
The fighters didn't stick with the bombers the whole way. They would meet the group at certain points along the way and cover them for a certain stage then go home on their own. The timing was arranged so their would be overlap in case the fighters fought hard and early and used up fuel early. It was designed tokeep the bombers covered but to allow the fighters to use efficent cruise speed for most of the transit time. This was especially important for the fighters at the extreme end of their range.
 
No! Drop tanks are used first so you can drop them when you encounter enemy. Very often the Germans would send a first wave of fighters up early just to get the escort to drop fuel tanks early.
Much of one leading edge tank would be used from taxi/takeoff/initial forming up.
Unlikey to get bounced over SE England, or over the channel for the next small LE Tank
 
Huh, I was under the illusion that the USN planes usually had long ranges, especially when fighting in the Pacific over vast distances.
Its not really an illusion, most spitfires had had 90 imp gal fuel whereas the Wildcat and P40 had about 110 gal. Given equal warm up, takeoff and landing allowance that extra 20 imp gal almost doubles combat radius or time on station.

Later USN fighters had long range in the naval context, but shouldn't really be compared to a freak like the P51.
 
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The snapshot of part of the table found at pg. 600 of the 'America's hundred thousand' book, covering the USAAF's requirement for long range escort job:
 

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Part of the issue is that the corsair and hellcat had excellent range for navy fighters of the time, but would suffer against a P51, because a P51 did not have the weight and space requirements related to folding wing mechanisms, and stiffer frames for carrier landings.

Also these planes were becoming operational at about the same time correct?
 
Part of the issue is that the corsair and hellcat had excellent range for navy fighters of the time, but would suffer against a P51, because a P51 did not have the weight and space requirements related to folding wing mechanisms, and stiffer frames for carrier landings.
P-51 was conceived around a much smaller, sleeker and lighter engine than it was the R-2800 the F6F and F4U had, thus P-51 was much smaller, sleeker and lighter aircraft than those naval fighters. Retrofit of a 2-stage Merlin still meant the aircraft is smaller, sleeker and lighter. Add the fact that V-1650-3 will offer more than 50% better mileage per power setting (even if not per actual HP), along with installation of fuselage tank of 85 gals (for 269 US gals total internal fuel, plus drop tanks) and result is a rangy performer with excellent timing.

Also these planes were becoming operational at about the same time correct?
F4U and P-47 in early 1943 (P-47 with more initial troubles, mostly with engine and radio interfering each another), F6F mid-1943, and P-51B in dec 1943.
 
P-51 was conceived around a much smaller, sleeker and lighter engine than it was the R-2800 the F6F and F4U had, thus P-51 was much smaller, sleeker and lighter aircraft than those naval fighters. Retrofit of a 2-stage Merlin still meant the aircraft is smaller, sleeker and lighter. Add the fact that V-1650-3 will offer more than 50% better mileage per power setting (even if not per actual HP), along with installation of fuselage tank of 85 gals (for 269 US gals total internal fuel, plus drop tanks) and result is a rangy performer with excellent timing.



F4U and P-47 in early 1943 (P-47 with more initial troubles, mostly with engine and radio interfering each another), F6F mid-1943, and P-51B in dec 1943.
Assuming the F4U's own teething problems with its landing gear aren't in consideration, its a great fighter that could go toe to toe with a butcher bird, but it was not as suited for the role of high level bomber escort from land airbases as the P51 was.
 
Assuming the F4U's own teething problems with its landing gear aren't in consideration, its a great fighter that could go toe to toe with a butcher bird, but it was not as suited for the role of high level bomber escort from land airbases as the P51 was.
F4U can do high level escort - USN was not funding a 2-stage supercharger for R-2800 for nothing. But it can't do it at ranges comparable to P-51B-K unless we add another fuel tank or two to increase internal fuel capacity to at least 350-400 gals, all in self-sealing tanks, along with drop tanks for another 300 gals at least.
A long range F4U flying at 25000 ft in ETO will certainly have less problems than P-38, from compressibility issues on.
 
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