F4U Corsair

I would LOVE to see those figures!! That had to be alot of work.

Colin1 said:

Hi Ivan
I know I'm being a bit slow here
so if I drew an imaginary line back through the bent section of the wing (looking at the a/c from head-on) and continued the line back into the cylindrical fuselage, it would - in 2D - pass through the centre of the circle created by the frontal aspect of the fuselage (the longeron datum line)?

I'm trying to get a fix on what this wing angle is at 90 degrees to, mating as it does to a cylindrical (fuselage) section.

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Don't fell bad. I've spent some time around a f4u-4b and I don't know what it is 90 degrees to either. The cross section is not round for the entire length of the cord.

renrich said:

There is no question that the intersection of the Corsair wing root with the fuselage was cleaner than the intersection of the wing and fuselage of the Hellcat with the fairing that was needed. That was a part of the reason that the Corsair had better performance than the Hellcat with essentially the same engine. The design philosophy of the Corsair was to have the smallest and cleanest air frame possible married to the most powerful radial engine available. The R2800 was chosen not only because of it's power but because it was a twin row engine which gave it a relatively small cross section and the fuselage of the Corsair was round like the engine and therefore had a small cross section. The wing intersection was a side effect of the effort to make the landing gear shorter and therefore stronger. It was fortunate that the amount of propellor clearance created was generous because the later Corsairs needed a taller tail wheel strut for aerodynamic and visibility effects. The prototype Corsair had all fuel in the wings and the guns in the nose. The desire to relocate the guns into the wings and most of the fuel into the fuselage and keep the fuselage slender resulted in moving the cockpit aft about three feet in order to create room for the fuselage fuel tank in production models. The moving of the cockpit created visibility problems, especially at high AOAs. The Corsair, as with all AC, was a series of compromises. The resulting AC, considering it's time frame, was an engineering tour de force.

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Actually the cockpit was moved back for cg considerations. The bent wing affords a better view of the ground than say an f6f. This was an advantage as a ground support aircraft. The issue was the length of the nose not affording good visibility over the nose on landing. Although there really is no useful information over the nose on any landing.

The cockpit was moved back in order to put the fuel tank in the fuselage and over the wing. That allowed the CG and the CL to coincide which is desirable. Also the usage of fuel caused no appreciable change in the CG. The cockpit was as far foward as it could be given the location of the fuel tank. There was no room for the fuel tank to be under the cockpit as in the F6F and P47.

I've always liked the look and power of the Corsair, and finally picked up my first model kit of one at the weekend. I'm now taking an interest in it and will do a bit of research (as with all models I've collected).

As the engine was the same 2000hp P&W Double Wasp as the Hellcat, was the performace of the Corsair much better than the Hellcat? They obviously had a wider tracked main undercarriage which would make landing more stable, and larger propeller and cleaner airframe allowing a better max speed at medium altitudes, but it has been mentioned earlier in this thread that they were more costly to build. According to Wiki, similar numbers (about 12,500 of each were built), both entering service in '43. The main operational difference seemed to be the Corsair not being the best for carrier operations so more suited to mainly land based (but carrier capable) Marine use, whereas the Hellcat was more suited as the Navy carrier based aircraft.

To me, the Corsair is the more glamorous of the two. What do others think?

The various models of the Corsair were faster at most altitudes, faster climbers, had better roll rates and were better at dive bombing( because the landing gear was able to be used as dive brakes, the Corsair was only slightly less accurate than the SBD) than the Hellcats. The Hellcat was somewhat less vulnerable to battle damage, was more forgiving to the more poorly trained pilot and was a little easier to maintain. One pilot said something like, "the Hellcat was a tame ***** cat, the Corsair was a high strung predator." The Corsair, when first flown, was a cutting edge design, using an engine still under development and a newly designed prop. It was also exploring flight regimes that were somewhat unknown. It had a long gestation period. The Hellcat, being a later and somewhat less sophisticated design went from the drawing board to operational status in a very short time.

operator18 said:

Don't fell bad. I've spent some time around a f4u-4b and I don't know what it is 90 degrees to either. The cross section is not round for the entire length of the cord.

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I would suggest perpendicular to the fuselage where the wing attaches to the fuselage.

Thanks Renrich, that's the impression I was getting from various sources; that the Corsair was a bit more of a wild beast to be tamed but with extra bite when handled with gained experience, whereas the Hellcat was a calmer more forgiving machine to fly, still an excellant fighter but perhaps didn't push the boundaries as far as the Corsair could.

Was the Hellcat a completely new design to the Wildcat, or just upgraded and up-engined?

"The Hellcat was somewhat less vulnerable to battle damage, ..."

Start at post #263 and follow the discussion regarding the "somewhat less vulnerable" issue.

http://www.ww2aircraft.net/forum/av...f4u-4-corsair-superior-738-18.html#post526511

The USN found that Corsairs were 58% more likely to be losses from AA fire than Hellcats when actually hit by AA during the same time period, flying from the same carriers and flying missions under the "same conditions" in "comparable operations" where the two aircraft received "about the same number of hits per sortie."

Notwithstanding the statistics, the fact is, that the Navy chose the Corsair over the Hellcat. AFAIK, no Hellcats served in Korea, the Corsair was heavily involved. The Hellcat was a completely new design over the Wildcat although there was a family resemblance. The Hellcat was much larger, designed for a larger engine and with a totally different landing gear layout.

There is a good discussion in that thread regarding the Navy's decision, which was well before the vulnerability issue was known, and the reasons for that decision. In hindsight, the Hellcat would have probably performed better than the Corsair in Korea (It would have done the job equally well and without the very serious vulnerability issue.)

Basically, the USN data compiled from over 22,000 sorties reveals that under comparable apples to apples conditions, for every 10 Hellcats lost, there were 16 Corsairs lost. To say that the Hellcat was "somewhat less vulnerable" is akin to saying that the F4U-1D Corsair was "somewhat less fast" than the Mig-15, which had about a 58% higher top speed. (420mph vs. 668mph)

It strains credulity to think that the Navy did not know about the supposed Corsair vulnerabilitiy issues long before the statistical data which some "experts" on this forum are so fond of quoting was available. The Navy and it's pilots knew as soon as the F4F4 was operational that the six gun design Grumman came up with at the insistence of the British was unsatisfactory and in fact a few F4F4s were built going back to the four gun configuration. The data that purports to show the Corsair vulnerability was published in June of 1946. If the data was as damning as is claimed then surely Vought would have been asked to make an effort to cure the vulnerability problem. The AU, a dedicated ground attack AC did relocate the oil cooler which is supposed to be the culprit but nothing was done in that area on post war F4U4s and F4U5s.

The facts are that the Corsair outperformed the Hellcat in almost every way. If one reads the comparison between a captured FW190 and a Hellcat and Corsair, even though both Navy fighters were adjudged to be able to cope with the FW, the Corsair had the performance edge in every way. The Corsair was a better air to air gunnery fighter because besides being faster, a better roller and climber it had much better control modulation.

The fact is that, in spite of "expert" claims to the contrary, the Hellcat and Corsair flew almost the same number of sorties in WW2, something over 60000 each and only 553 Hellcats were lost to AA and only 349 Corsairs so neither AC seemed to be particularly vunerable to AA. The Hellcat had 340 operational losses which was 61% of the AA losses and the Corsair 230 which was 66% of the AA losses and one supposes that our pilots were not purposely trying to destroy our aircraft like the Japanese were. Some "experts" will claim that the bulk of Corsair air to ground sorties were flown against undefended islands but those "experts" ignore the fact that in the Philipines campaign the Corsairs carried by far the heaviest load and those targets were heavily defended.

To say that," in hindsight, the Hellcat would have probably done better in Korea" when no reputable author or source I have ever heard of has drawn that conclusion seems to be a stretch to me. However, everyone is entitled to an opinion, especially on this forum with all of us "experts."

IMO, when the Navy made the decision to replace Hellcats with Corsairs on carriers, the Navy knew about the strong and weak points of both fighters and made the correct decision based on their immediate and long term priorities.

"It strains credulity to think that the Navy did not know about the supposed Corsair vulnerabilitiy issues long before the statistical data which some "experts" on this forum are so fond of quoting was available."

This was already addressed in the thread. I'm not sure what else can be said. Again, for those interested in reading the discussion, start with post #263:

http://www.ww2aircraft.net/forum/av...f4u-4-corsair-superior-738-18.html#post526511

"The facts are that the Corsair outperformed the Hellcat in almost every way. If one reads the comparison between a captured FW190 and a Hellcat and Corsair, even though both Navy fighters were adjudged to be able to cope with the FW, the Corsair had the performance edge in every way."

Yes! And don't stop there. Clearly, the Navy actually knew about the tremendous performance advantage too. And yet, the Navy declared the following, with the benefit of hindsight, after WWII:

"The F6F was slightly superior to the F4U in combat, apparently chiefly because of its greater ability to survive damage."

and

"The F6F appears to have had considerable advantage over the F4U when flown under the same conditions. Receiving about the same number of hits per sortie in comparable operations, the F6F had a far lower rate of loss per plane hit."

Comparing the Hellcat and Corsair, during the same time period, flying from the same carriers and flying missions under the "same conditions" in "comparable operations" where the two aircraft received "about the same number of hits per sortie," the Corsair had a 58% greater chance of not making it back when actually suffering AA damage. Given the enormous performance advantage of the Corsair, it would indeed take a huge vulnerability weakness (like a 58% higher probability of not making it back when suffering AA damage) to cause the Navy to declare that the Hellcat was actually superior in combat "chiefly because of its greater ability to survive damage."

"The fact is that, in spite of "expert" claims to the contrary, the Hellcat and Corsair flew almost the same number of sorties in WW2, something over 60000 each and only 553 Hellcats were lost to AA and only 349 Corsairs so neither AC seemed to be particularly vunerable to AA. The Hellcat had 340 operational losses which was 61% of the AA losses and the Corsair 230 which was 66% of the AA losses and one supposes that our pilots were not purposely trying to destroy our aircraft like the Japanese were. Some "experts" will claim that the bulk of Corsair air to ground sorties were flown against undefended islands but those "experts" ignore the fact that in the Philipines campaign the Corsairs carried by far the heaviest load and those targets were heavily defended."

When you mix together, for both aircraft, all missions over the entire war, it becomes impossible to disentangle and control for factors that interfere with a comparative analysis ... about anything. The more than 22,000 sorties during the same time period, where both aircraft operated from the same carriers, flying missions under the "same conditions" in "comparable operations" and where the two aircraft received "about the same number of hits [AA] per sortie," enable us to draw valid conclusions about the comparative vulnerability to AA fire. The Navy thought so too and pointed out that under apples to apples conditions, the Corsair was 58% more likely not to return from combat.

"To say that," in hindsight, the Hellcat would have probably done better in Korea" when no reputable author or source I have ever heard of has drawn that conclusion seems to be a stretch to me. However, everyone is entitled to an opinion, especially on this forum with all of us "experts.""

I'm going to defer to JoeB here and just cut and paste his comments from post #319 of that thread:

Re: F4U and F6F ground fire vulnerability and mountain or mole hill, it is what it is. It's as statistically clear as it ever would be that the F4U was significantly more vulnerable. How important that was would depend a lot on what the key missions were. Early in WWII it wouldn't have been very important at all. By 1945 it was somewhat important. In a war where carrier planes conducted constant air strikes with essentially no air or anti-ship threat for months on end (see: Korea) it was a relatively quite serious issue. It was too late to bring the F6F back, but it almost surely would have been a better a/c for the F4U's mission in Korea. Again see 1945 stats, F4U's did *not* carry more ordnance per sortie from carriers than F6F's, not in actual practice. And in Korea, typically, high value targets weren't being smashed by a few decisive strikes. The realistic goal was harassing the enemy, gradually inflict casualties and damage it was hoped, and only occasionally, perhaps, scoring any really satisfying success. The heavy losses of beat up old F4U-4's were not such a big deal, they were going to the boneyard soon anyway, but the losses of pilots was more of an issue, even from a completely non-sentimental POV of trying to re-expand naval aviation for the Cold War. To this was added the F4U's inherently higher accident rate, especially in the more difficult operating conditions typically faced by carrier a/c in Korea compared to the Pacific War, more especially in the winter time.

But as shown by all these debates here, it wasn't hard at all to miss the fact of greater F4U vulnerability before the stats were accumulated (or in these threads, before people are fully aware of them and just how apples to apples they are). Even afterward naval air thinking emphasized dashing hell-for-leather wars like WWII. And even in the actual conditions of Korea once apparent, leadership simply had a blind spot about air crew losses that didn't make a lot of sense compared to the actual results achieved. It's hard to explain certain decisions in KW any other way (goes for the USAF as well).

http://www.ww2aircraft.net/forum/av...f4u-4-corsair-superior-738-22.html#post532571

I'd point to some stuff re. F6-F F-4U as competitors for place on post-WW2 carriers:
-I see a way of thinking for post-WW2 composition of carrier air wing as this: F8-F as dedicated fighter, F4-U as multirole plane, and AD-1 as dedicated bomber. In the end F8-F barely managed to be a CV asset, leaving F4-U as dedicated fighter.
-Raw performance (as a fighter) of latest F4-U was much greater then of latest F6-F, so any concievable, post-WW2opposition would present a problem for F6-F.
-Grumman started producing F8-F in mid 1945, which implies that F6-F would be no longer produced on Grumman's lines.

Question: were the post-WW2 Corsairs modified in order to increase the resistance to AAA?

The problem was the placement of the cooler right? So any attempt at fixing that would result in significant re-design.

The decision for the Corsair over the Hellcat might root in the fact that they had to choose a multirole fighter. I think the Corsair left more room for additional equipment such as radar and so on. Certainly the Corsair has more of chance to succeed against the final generation of piston fighters (Ki 84 and hypothetically fighters comparable to Ta 152, Yak 3 or La 9). In Korea they soon were not really used as fighters any longer, though. It still carried a large payload, but for everyday work it seems the F6F might indeed be a overall easier and less troublesome bird, even in Korea. Its speed disadvantage was not really important as both would be outclassed by the jets by far.

This seems to have become a comparison of the two aircraft, so here's my "two cents"....... From my work here at NMNA we've taken apart and rebuilt many of both types. The aircraft are two completely different birds. The Corsair evolved from a high performance design for a pursuit aircraft or "fighter" in 1935.
The Hellcat was designed as a replacement for the F4F Wildcat designed in the same year and put into production in 1940 when the Hellcat was already on the drawing board as a revamped F4F but ended up as a new design and really ramped up when it was found how far behind the Japanese designed Zeke it really was. Due to tactics the wildcat held it's own but wasn't near the performance necessary to overcome it. The development of the Hellcat finalized after the example of a Zeke was recovered at Acutan in the Aleutian Islands and testing was accomplished. The wing was the primary change being enlarged to enhance maneuverability. This had the added effect of enhancing "flyability" and helped scores of new pilots to an easy transition to type. I've spoken with many pilots who flew both types and the consensus is that the F6F is a big friendly bear and the F4U is a wild beast. The biggest difference is the cooling in the wing root of the Corsair with a slim fuselage and the Hellcat cooling is in the cowling and fuselage resulting in the large rounded fuselage with the high rib on top for lateral stability. It was more than an equal for the Zeke(or "Zero") and took the fight to them from 1 August 1943.
Marine units had been flying the F4U from land bases for about 3 Months by then as Carrier Trials for the type hadn't been positive and we sent it to the British who learned how to fly it from Carriers first with the difficult stalling characteristics and vicious "Bounce" on landing........

Hollywood, your analysis of the two AC is interesting and informative. However, I believe that the story of the FAA being the first to tame the Corsair for carrier ops is a myth. If you study the chronology of Corsair ops in Dean, "America's Hundred Thousand," Blackburn's VF squadron had readied the Corsair for carrier ops before the FAA had even tried to operate the Corsair from carriers. In addition, there is a training film on Zeno's of the F4U1 which shows a field carrier landing employing the curving base and short final which has been credited to the FAA. That F4U1 has insignia proving the film was probably shot long before the FAA got their hands on Corsairs. The two primary drawbacks for Corsairs carrier ops were the poor visibility over the nose and the excessive bounce of the main gear oleos. The visibility problem was alleviated somewhat in the F4U1As by the revised canopy and raising the pilot seat and the oleos were field modified by trial and error and eventually on production models. Also in Dean, there are several remarks by pilots of Hellcats which allude to it's marginal performance characteristics over Japanese opposition. That big wing and deep fuselage on the F6F, compared to the F4U, was paid for in a diminuation in performance.

Hollywood said:

The development of the Hellcat finalized after the example of a Zeke was recovered at Acutan in the Aleutian Islands and testing was accomplished. The wing was the primary change being enlarged to enhance maneuverability. This had the added effect of enhancing "flyability" and helped scores of new pilots to an easy transition to type.

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That the Aleutian Zero had any influence on the design of the Hellcat is an absolute myth. The contract firmly fixing the Hellcat configuration was signed six months prior to the crash of the Aleutian Zero.

The Aleutian Zero was an A6M-2 flown by Petty Officer Koga who made an emergency landing June 3, 1942. Koga was killed when the Zero overturned. It took the Navy five weeks to salvage the aircraft, another seven weeks to get it to NAS North Island in San Diego, and to complete major repairs including locating a replacement propeller. The Aleutian Zero arrived in San Diego in August and was first flown by the USN on 20 September 1942.The Navy/AAF comparative tests which disclosed the 'secrets' of the Zero were not completed until December 1942.

The F6F configuration was firmly fixed on January 7, 1942 when the Navy awarded a contract for 1,264 Hellcats. Airframe design had begun in June 1941. The XF6F-1 with the stop-gap R-2600 engine first flew June 26, 1942 - before the Zero was recovered from the Tundra. The XF6F-3 with the R-2800 engine flew July 30, 1942, a month before Koga's Zero arrived in San Diego, and two months before it was flown.

While the captured Zero was important in the refinement of tactics, it provided no direct input into the Hellcat design.

renrich said:

...I believe that the story of the FAA being the first to tame the Corsair for carrier ops is a myth. If you study the chronology of Corsair ops in Dean, "America's Hundred Thousand," Blackburn's VF squadron had readied the Corsair for carrier ops before the FAA had even tried to operate the Corsair from carriers. In addition, there is a training film on Zeno's of the F4U1 which shows a field carrier landing employing the curving base and short final which has been credited to the FAA.

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Correct on both counts. First carrier-based combat usage of the Corsair was with the USN, and by night fighters no less! VF(N)-101 took their F4U-2's aboard Enterprise and Intrepid (four plane groups on each boat) in January '44 and began combat operations with the fast carriers. First British combat use of carrier-based Corsairs was April '44.

The curved approach pre-dates the Corsair. This was the standard approach from the days of biplane carrier fighters. Can't say whether or not the British first implemented it, but it was not with the Corsair.

Actually Corsairs operated from carriers in combat during the Battle of the Solomon Sea, November, 1943. This was not official with the bureaucrats in the US but land based Corsairs from VF17 had tail hooks attached and after protecting the fleet during raids on Rabaul, landed on carriers in order to refuel and then go back to land bases. VF17 claimed 18.5 kills for two losses. VF17 with F4U1As was deployed on Bunker Hill in September, 1943, but was off loaded at Pearl Harbor and diverted to land base duty.