Supose the Corsair went to the 8th AF !

Timppa · Dec 16, 2008

renrich said:
We have been through this before but I agree with Bill that an Army F4U would have probably replaced the P47 and perhaps also P38. 600 or 800 pounds lost would have made a big difference in performance.

Arhur Price writes:" At the end of the war the necessary deck landing equipment and strengthening amounted about 4% of the loaded weight of a carrier fighter (some 480 pounds for the 12,039 pound Corsair)"

The same source gives the practical combat radius (as defined by the Navy)of early F4U as 425 miles. This is the same as early (pre D-25) P-47's and much less than P-51's (700 miles, the USAAF and Navy definitions are slightly different though).

The first combat for the F4U was Feb. 1943, only two months before the P-47
The F4U-1D, which carried more external fuel (but less internal), saw service mid 1944, about the same time as late P-47D and P-51D.

At typical escort altitudes, 25,000-30,000 feet, the P-47 was faster and climbed better. It had 33% more firepower and the better dive limit speed (500 vs. 443 mph).

If we don't make some 'what if' scenarios for much earlier service introduction date for the F4U with extended range, I don't see it as much of an improvement over the P-47.

Also the USAAF was very slow to see the need for long range escort fighter, as they believed that "the bombers will always go thru". This belief was shattered only after the second Schweinfurt raid.

fly boy · Dec 16, 2008

see the one thing about the f4u is that is was the mustang of the pacific and was made for that theater if they went to europe two things might have happend: one the F4U might be good with both ground attack and escort but it might have been a problem with the air mixing with the engine and two: there are already the p-51 the 47 the 38 and the spitfire so the F4U would have been used in like night fighting or base defence. That would have helped at like Y-29 or other allied bases over there but not too much

KrazyKraut · Dec 16, 2008

Very good post Timppa. I agree completely.

renrich · Dec 16, 2008

My source, "America's One Hundred Thousand," by Francis Dean shows the P47C and early D model with an internal fuel capacity of 305 gallons and a max range of 835 miles which includes no consideration of warmup, takeoff, climb out, cruise, combat, go back and reserve. Same source has a table with combat radiuses for Army fighters. The P47C with 305 gallons of internal fuel shows a combat radius including all the above considerations of 175 miles. The same source shows F4U1 with max range of 1500 miles with internal fuel of 361 gallons but there is no table showing a realistic combat radius. One can extrapolate that a combat radius for F4U1 would be about 275 miles with no external fuel. If external fuel tanks were added the gain would be roughly the same for both AC. It is interesting to read about performance of WW2 AC because what one sees often is numbers which might be achieved under perfect conditions but probably would never happen in the real world under combat conditions. I have posted this before but one of my uncles was an IP in WW2 in P39s and P47s and he said when they went to the gunnery ranges on the Gulf Coast, the Navy pilots in F4Us would gleefully jump them in mock dogfights and when in a P47 they had no chance. Of course those bounces were at low altitudes. Similar story was told in Blackburn's book about the Jolly Rogers while training on the East Coast. The P47s could have a edge above 25000 feet but could not get the Corsairs to go up and play with them there. One wonders if an Army Corsair might not have a supercharger installation like the Mustang which would optimise performance at higher altitudes and also be automatic. Another advantage of an Army Corsair would be the ability to operate off of short fields. The P47 needed a lot of runway to get off the ground. The Corsair had considerably better turn and roll capability over the Jug also.

drgondog · Dec 16, 2008

renrich said:
My source, "America's One Hundred Thousand," by Francis Dean shows the P47C and early D model with an internal fuel capacity of 305 gallons and a max range of 835 miles which includes no consideration of warmup, takeoff, climb out, cruise, combat, go back and reserve. Same source has a table with combat radiuses for Army fighters. The P47C with 305 gallons of internal fuel shows a combat radius including all the above considerations of 175 miles.

The practical range for the and the D-2 and -5's were Ems River, Munster, Dummer Lake area. (170-200 max radius, less with headwinds) For several months after the bloody October 14 losses, 8th BC flew not much further because of the limitations of the early P-47's. The F4U-1 had at least 100miles radius advantage on the P-47D's until the -25 (IIRC) showed up with wing racks. This is why the Mustangs took over target Escort duties.

The same source shows F4U1 with max range of 1500 miles with internal fuel of 361 gallons but there is no table showing a realistic combat radius. One can extrapolate that a combat radius for F4U1 would be about 275 miles with no external fuel. If external fuel tanks were added the gain would be roughly the same for both AC. It is interesting to read about performance of WW2 AC because what one sees often is numbers which might be achieved under perfect conditions but probably would never happen in the real world under combat conditions.

The P47s could have a edge above 25000 feet but could not get the Corsairs to go up and play with them there.

However, that is where the bombers were - and expectations for German fighters

One wonders if an Army Corsair might not have a supercharger installation like the Mustang which would optimise performance at higher altitudes and also be automatic. Another advantage of an Army Corsair would be the ability to operate off of short fields. The P47 needed a lot of runway to get off the ground. The Corsair had considerably better turn and roll capability over the Jug also.

I see no reason offhand why a supercharger installation would not be feasible but it would have probably taken up some fuel cell space. The Corsair so configured should give it equivalent or slightly better climb performance than the P-51B at 25-30K, slightly better turn but I would think slower than the 51.

renrich · Dec 16, 2008

Bill, I don't understand why the Merlin Mustang would have better high altitude performance than the Corsair except for supercharger optimisation. They both had two speed, two stage superchargers. The Corsair's had to be shifted manually from low to high blower whereas the Mustangs was automatic. Can you tell me what the difference was?

drgondog · Dec 16, 2008

Timppa said:
Arhur Price writes:" At the end of the war the necessary deck landing equipment and strengthening amounted about 4% of the loaded weight of a carrier fighter (some 480 pounds for the 12,039 pound Corsair)"

That probably is about right for carrier landing requirements but the folding wing structure was equally offensive relative to USAAF requirements.

The same source gives the practical combat radius (as defined by the Navy)of early F4U as 425 miles. This is the same as early (pre D-25) P-47's and much less than P-51's (700 miles, the USAAF and Navy definitions are slightly different though).

The -10's didn't get to ETO until January 1944 and by the time the -25's reached the 56FG, the huge battles over Germany were pretty much decided and the P-47s were not the dominant factor

The first combat for the F4U was Feb. 1943, only two months before the P-47
The F4U-1D, which carried more external fuel (but less internal), saw service mid 1944, about the same time as late P-47D and P-51D.

At typical escort altitudes, 25,000-30,000 feet, the P-47 was faster and climbed better. It had 33% more firepower and the better dive limit speed (500 vs. 443 mph).

The question would be how much does this matter if the P-47's couldn't perform Target Escort past Stuttgart/Dummer Lake radius. And, the P-51B did quite well with only 50% of P-47 firepower so the F4U-1D had a 50% Advantage over the P-51B with few jamming issues. Dive limit would be a factor but not to same extent as the P-38.

Also the USAAF was very slow to see the need for long range escort fighter, as they believed that "the bombers will always go thru". This belief was shattered only after the second Schweinfurt raid.

However slow 8th was in understanding the peril, it used close escort from RAF as well as 4th and 31st FG Spitfires from the very beginning of its Ops and the LW learned to wait until they turned back.. ditto with P-47C and D through -10/20 series. By that time the Mustang was firmly entrenched for Target Escort and the LW could no longer retreat and form up in large gaggles.

I believe that Schweinfurt would still be too far for the F4U-1 in fall 1943, but it would have been a factor at Hannover/Brunswick/Kassel/Hamburg battles.

drgondog · Dec 16, 2008

renrich said:
Bill, I don't understand why the Merlin Mustang would have better high altitude performance than the Corsair except for supercharger optimisation. They both had two speed, two stage superchargers. The Corsair's had to be shifted manually from low to high blower whereas the Mustangs was automatic. Can you tell me what the difference was?

My belief is that the 51 was sufficiently cleaner as an airframe and would have continued to be faster as Hp available grew for both ships - the P-51H should have demonstrated the differences at both high and low level.

kool kitty89 · Dec 16, 2008

The performance of the F4U-4's engine was much better at altitude and had 200 more hp available than the F4U-1D's 2,250 hp engine (water injection), even when compared at low altitude.

The supercharger of the P&W engines (including the 2-stage R-1830-76/86 of the F4F-3 and F4F-4) had a single stage single speed "engine stage" (as with the turbocharged US engines) along with a 2-speed clutched "auxiliary stage" that could also be put in neutral. (to improve perfromance at very low altitude) So it actually had 3 supercharger settings. (and thus a somewhat smoother power curve)

The Merlin's 2-stage supercharger had both impellers on a single shaft running at the same speed, with 2 speed gearing and was barometrically controlled.
I beleive the intercooler systems used differed as well.

On the P-47's range, all the operational early models (pre wing rack C's and D's) could carry a 200 US gallon belly tank which added around 550 miles to the maximum range. (1,400 mi at ~220 mph at 10,000 ft without reserve) So the maximum combat radius would probably have been close to 500 mi.

syscom3 · Dec 17, 2008

Seems to me that if the B17's were up at 30,000 feet, thats where the LW had to be to fight them.

The P47 was designed frm the onset to fight up there, so unless the Corsair met or exceeded the P47's performance, I'd see no reason to use the Corsairs.

kool kitty89 · Dec 17, 2008

I beleive the B-17 usually cruised in the 25,000 ft area (though fighters may be providing top cover at 30,000 ft). I think Bill knows more on this.

It should be noted that the Mustang's V-1650-7 (high blower 67" Hg WEP 28,000 ft, 61" at 30,000 ft) was more popular than the initial V-1650-3 (high blower 67" 23,500 ft, 61" at 25,500 ft) (all figures for high speed -with ram- not for low speed/climb which should be 2-3,000 ft lower)

The latter's critical altitude only being slightly higher than the F4U-1's R-2800-8.

MikeGazdik · Dec 17, 2008

It looks as though the only thing the Thunderbolt lacked was range, other than that it obviously got the job done. It looks as though the Corsair may have extended the range of the escort slightly, but it still would not have been able to complete the escort mission like the Mustang.

Now taking the range issue out of the question, riddle me this. How would the AAF Corsair have done against the Bf109, Fw190 and others. I would say that if they were up in the mid 20k flight area, the Messerschmitts would have given the Corsairs some real problems. The Focke Wulf and the F4U would have been more of an equal at those altitudes. As the fighting came down lower, I think the F4U would have been better able to handle the Bf109. The Fw190 and F4U would remain locked in equality I believe, regardless of altitude.

renrich · Dec 17, 2008

Did a little research last night and answered my own question about whether the Corsair engine- supercharger could not have been optimised like the Mustang for better high altitude performance. The answer is: It was. The F4U1D which was contemperaneous with the P51D had 2000 HP at SL with Mil power. The P51D had 1490 HP, SL, Mil power. At 30000 feet, the Corsair had 1250 HP, Mil power, the Mustang, 960 HP, Mil power. The percentages of power retained were 63% and 64%. The power loadings were 10.6 for the Mustang and 9.83 for the Corsair. The Corsair at that altitude would have slightly outclimbed the Mustang and the Mustang because of less drag would still have been slightly faster, based on those numbers. The F4U1D at 20000 feet could make 425 mph where it began dropping off. My source on the FW190D-9 shows the Vmax to be 426 MPH at 21650 feet where it began dropping off. I would assume that the FW would outclimb both the Mustang and Corsair at those altitudes. If the Mustang was adequate against the FW as an escort fighter, then why would not the Corsair have been also, disregarding the range advantage of the P51D. It would appear to me that an Army version of the Corsair, lightened by 400 to 700 pounds and with better range than the P47 would have done well as an escort until the Merlin Mustangs came along. Bill, what would be your estimate of the proportion of ACM in the ETO which took place above and below 25000 feet, keeping in mind that the medium bombers and B 24s seldom got above 20 000 feet?

Lucky13 · Dec 17, 2008

What about Goodyears F2G "Super" Corsair with a Pratt Whitney R-4360 twenty-eight cylinder, four row radial air-cooled engine? Often said that the origin of the aircraft was as an interceptor of low-flying Japanese Kamikaze, its actual beginnings came about in 1939 when the Pratt and Whitney company first proposed its enormous new engine. Thus the F2G lineage was tied to its engine design rather than tactical requirements...
Had the engine come earlier....

Length: 33 ft 9 in (10.3 m)
Wingspan: 41 ft (12.5 m)
Height: 16 ft 1 in (4.9 m)
Wing area: 314 ft² (29 m²)
Empty weight: 10,249 lb (4,649 kg)
Loaded weight: 13,346 lb (6,054 kg)
Max takeoff weight: 15,422 lb (6,995 kg)
Powerplant: 1× Pratt Whitney R-4360-4 "Wasp Major" 28-cylinder radial engine, 3,000 hp (2,200 kW)

Performance
Range: 1,955 mi (1,699 nm, 3,146 km) with external tanks
Service ceiling 38,800 ft (11,800 m)
Rate of climb: 7,000 ft/min (35.6 m/s)
Wing loading: 42.5 lb/ft² (208 kg/m²)
Power/mass: 0.22 hp/lb (370 W/kg)

Armament
Guns: 4× .50 caliber (12.7 mm) M2 Browning machine guns, 400 rounds/gun
Rockets: 8× 5 in (127 mm)
Bombs: 1,600 lb (725 kg)

Marshall_Stack · Dec 17, 2008

renrich said:
. I have posted this before but one of my uncles was an IP in WW2 in P39s and P47s and he said when they went to the gunnery ranges on the Gulf Coast, the Navy pilots in F4Us would gleefully jump them in mock dogfights and when in a P47 they had no chance. Of course those bounces were at low altitudes. Similar story was told in Blackburn's book about the Jolly Rogers while training on the East Coast. The P47s could have a edge above 25000 feet but could not get the Corsairs to go up and play with them there. One wonders if an Army Corsair might not have a supercharger installation like the Mustang which would optimise performance at higher altitudes and also be automatic. Another advantage of an Army Corsair would be the ability to operate off of short fields. The P47 needed a lot of runway to get off the ground. The Corsair had considerably better turn and roll capability over the Jug also.

Out of curiosity, were the P-39s able to tangle with the Corsairs at low altitude?

It makes sense that the Corsair would be better at low altitudes since the P-47 had the weight of the turbocharger system and two additional machine guns. The bigger prop of the Corsair would seem to make a difference too.

renrich · Dec 17, 2008

My uncle never mentioned any mock dogfights with the P39. Only with P47. The P39s were, I believe phased out pretty early in the war but he did say that he did not like the P39, had bad spin characteristics and said that the pilot could get a lot of bumps on the head during a spin because cockpit was so narrow. I had six uncles in WW2 but all are gone now except one who has Alzheimers. Lucky, I have read that the F2G with that big engine had little better performance than the F4U4 and that was the reason the AC was not produced. I saw the "Super Corsair" in an air race once but it was not based on the F2G I don't think. Did not have the bubble cockpit. The few F2Gs produced did spend some time on the air race circuit shortly after the war.

kool kitty89 · Dec 17, 2008

Renrich, the F4U-1D had the same engine as the -1/1A (R-2800-8 ), but added water injection to make the R-2800-8W. (this mainly increased WEP at lower levels due to increased boost limit, but there's also the charge-cooling effect which would still be advantageous above the critical altitude)

As I mentioned, the high altitude performance (in terms of crit alt for WEP) is only slightly worse for the F4U-1 than the P-51B/C/D with the V-1650-7 (though less than the V-1650-3, and as mentioned the lower alt -7 tended to be preferred). The slight improvment of water injection at high alt with the F4U-1D would have made this gap even smaller.

The F4U-4 featured a more engine (R-2800-18W) with a powerful supercharger, allowing greater power at all heights and better high altitude performance. (the F4U-5 got an even more powerful engine with the R-2800-32E)

Also, a note on the the P-47's early 200 gal "ferry" belly tank. (from what I've read there may actually be 2 different typs of early drop tanks, both seem to be of laminated paper, at least one of them is of US origin and is a banana shaped, long, semi-conformal tank, while the other looks similar to the 108 gal British paper tank, but somewhat larger and proportioned differently)
Anyway, early 200 gal the paper ferry tank was (as the name suggests) designed for use on ferry flights, not combat. The tank was unpressurized and thus could not be used over ~23,000 ft.

renrich · Dec 18, 2008

Read something interesting about an "Operation Danny," which would have involved US Marine Corsairs in the ETO. The plan was that in 1944, several squadrons of Marine Corsairs were to launched off of CVEs near the French coast to go in and try to knock out the V1 launching sites with Tiny Tim rockets. The plan was vetoed by General Marshall because, it was said, he did not want any Marines in the ETO getting publicity like they did in WW1.

renrich · Dec 18, 2008

KK, my source says that the first F4U1A was fitted with the water injection engine on Nov. 25th, 1943, the 1551st Corsair built. It also has a table which indicates that some Corsairs came from the factory with the 8W engine before the first F4U1D was produced in April 1944. The 8W engine had a critical altitude of 21000 feet where it produced 1650 HP at military power. I know a number of F4U1s were retrofitted with water injection and I recall that the F4U1 that Ira Kepford flew in an engagement where he got 3 or 4 kills had water injection.

drgondog · Dec 18, 2008

renrich said:
Did a little research last night and answered my own question about whether the Corsair engine- supercharger could not have been optimised like the Mustang for better high altitude performance. The answer is: It was. The F4U1D which was contemperaneous with the P51D had 2000 HP at SL with Mil power. The P51D had 1490 HP, SL, Mil power. At 30000 feet, the Corsair had 1250 HP, Mil power, the Mustang, 960 HP, Mil power. The percentages of power retained were 63% and 64%. The power loadings were 10.6 for the Mustang and 9.83 for the Corsair. The Corsair at that altitude would have slightly outclimbed the Mustang and the Mustang because of less drag would still have been slightly faster, based on those numbers. The F4U1D at 20000 feet could make 425 mph where it began dropping off. My source on the FW190D-9 shows the Vmax to be 426 MPH at 21650 feet where it began dropping off. I would assume that the FW would outclimb both the Mustang and Corsair at those altitudes. If the Mustang was adequate against the FW as an escort fighter, then why would not the Corsair have been also, disregarding the range advantage of the P51D. It would appear to me that an Army version of the Corsair, lightened by 400 to 700 pounds and with better range than the P47 would have done well as an escort until the Merlin Mustangs came along. Bill, what would be your estimate of the proportion of ACM in the ETO which took place above and below 25000 feet, keeping in mind that the medium bombers and B 24s seldom got above 20 000 feet?

I suspect that absent going through every encounter report there is no way of estimating.. What I would say is that most engagements started around bomber escort level and rapidly went to the deck. The 51, 109, 190 and P-47 all had great dive speeds so the a/c in front trying to split S and dive away better have a 1/2 mile lead and maybe cloud cover, to get away.

The Corsair dove well but might have experienced some problems initiating and staying in dive with a 109. I don't know much about this characteristic of the F4U other than 'instant' compressibility wasn't a problem like the P-38 through the mid range J.

I doubt that the slight variations between the F4U and P-51 in performance would have mattered against the Fw 190/Me 109 as the tendencies of evasion by the LW takes the fight to medium and low altitude. If anything the F4U is slightly superior here and definitely more durable attacking airfields - all the debates about oil coolers notwithstanding..

IF the F4U could not stay with either of the two German fighters that might have influenced them even more to simply attack then dive away... but I doubt there would be real significance in the differences?

The interesting point about these debates is that if the F4U was deemed slightly inferior at 25K and more inferior at 30K, they would have been assigned to 2nd BD and escort B-24s.. What a lot of folks miss is that escort ceilings for 51s rarely topped 28K and that was for high cover. True, if they spotted top cover 109s early enough maybe two flights might climb to go after them but the heavy hitters were the 190s and they didn't often get above the bomber stream, particularly for the B-17s.

I personally think the F4U was simply a better airplane than the P-47 and clearly equal to Mustang, 109 and 190 - better in some profiles not as good in others.. but the P-47 as good as it was above 30,000 feet, wasn't getting to the dance over Germany and relegated to 9th AF where it wasn't going above 15,000 feet - notably not its performance strike zone.

Strictly opinion

Supose the Corsair went to the 8th AF !

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