P-47N Thunderbolt vs. F4U-4 Corsair - Which was superior?

[DAVIDICUS]

Renrich, I have seen that too and don't know what to make of it.

Snorts (a past forum member who was apparently banned) recounted his father's experiences flying both the D and N with respect to roll and commented that the N rolled better than the D. He also posted about his father's experiences in mock dogfights with Corsairs.

See Posts starting with #241

http://www.ww2aircraft.net/forum/aviation/p-47n-thunderbolt-vs-f4u-4-corsair-superior-738-17.html

I have also read in numerous places (as I know you have too) that the N rolled better than the D such as the following:

The XP-47N took to the air for the first time on July 22, 1944. Test comparisons were made with a P-47D-30-RE throughout the early portion of the evaluation period. Much to everyone's surprise, the XP-47N, with its greater wingspan and higher weight actually proved to have better roll performance than the D model. At 250 mph TAS, the N attained a maximum roll rate just over 100 degrees/second. The P-47D-30-RE could manage but 85 degrees/second at the same speed. At higher speeds, the N widened the gap further. In mock combat with a P-47D-25-RE, the new fighter proved to be notably superior in every category of performance. In short, the XP-47 waxed the venerable D model regardless of who was piloting the older fighter. The new wing was part of this newfound dogfighting ability, however, the more powerful C series engine played a role too. The additional horsepower allowed the N to retain its energy better than the older Thunderbolt. Perhaps the greatest performance increase was in maximum speed. Though not as fast as the stunning P-47M, the heavier N was fully 40 mph faster than the P-47D-25-RE and could generate speeds 30 mph greater than its principal rival, the Mustang. Scorching along at 467 mph @ 32,000 ft., the N could not be caught by any fighter in regular service with any air force on earth with the single exception of its M model sibling. This combination of wing and engine had pushed the N model up to the top rank of the superlative prop driven fighters then in existence.

The testing program included determining the maximum range of the fighter. This was done with various combinations of fuel loads and external drop tanks. Ultimately, a test flight was made from Farmingdale to Eglin Field in Florida. The XP-47N took off with two 315 gallon drop tanks hanging from the under-wing hardpoints. Usable fuel in these tanks totaled 600 gallons. Added to the internal fuel load, the N eased off the runway with 1,170 gallons of fuel (usable). At a gross weight of 20,166 lbs., the Thunderbolt headed south in company with a P-47D chase plane. Arriving off the coast, east of Elgin in 3 hours, 44 minutes, the external tanks were dropped. Another P-47D, already waiting at Elgin, took on the N in a mock dogfight that lasted for twenty minutes. The throttle was advanced to military power for 15 minutes of this time, with an additional five minutes in the War Emergency Power (WEP) detent. After these fun and games were concluded the N was turned around and flown back towards Farmingdale. Heavy weather over Long Island caused the plane to divert to Woodbine, New Jersey. Having flown 1,980 miles, total fuel usage was measured at 1,057.5 gallons. There was still more than 112 gallons of usable fuel remaining in the main fuselage tank, enough for another 330 miles @ 1,700 rpm in auto-lean. The XP-47N was now the king of long-range single engine fighters (the all time leader of long range escorts was the P-38L-1-LO, which could claim a combat radius of nearly 1,500 miles under ideal conditions).

Sources:

Dean, Francis, "America's Hundred Thousand: U.S. Production Fighters of WWII."
Bodie, Warren M., "Republic's P-47 Thunderbolt: Seversky to Victory."
Bodie, Warren M., "The Lockheed P-38 Lightning."
Boyne, Walter, "Clash of Wings: WWII in the Air."
Ferguson Pascalis, "Protect and Avenge: The 49th Fighter Group in WWII."
Freeman, Roger, "Thunderbolt, A History of the Republic P-47."
Freeman, Roger, "The Mighty Eighth."
Hammel, Eric, "Air War Europa."
Johnson, Robert, "Thunderbolt!"
Scutts, Jerry, "P-47 Thunderbolt Aces of the 8th Air Force."

Seversky Aircraft and Republic Aviation

It would certainly be interesting to get some data on roll rates for the P-47D and P-47N. The P-47N had a larger wing area, squared wing tips and larger ailerons as well.

It would appear that squaring the wings can have a dramatic effect.

I'm trying to find data and information on roll rates. I see tactical trials by the RAF in 1943 regarding mock combat between the P-47C other aircraft.

Against Spitfire Mk. IX

25. Manoeuvrability – The good aileron control gives the P-47 an excellent rate of roll even at high speeds, and during mock combats it was considered to roll as well as, if not better than the Spitfire at about 30,000 feet. At lower altitudes there is nothing to choose between them.

Against Typhoon IB

30. Manoeuvrability – The P-47C was considered far superior in rate of roll to the Typhoon, and at 20,000 feet in turning circles proved itself slightly better.

Against Mustang X

35. Manoeuvrability – The rate of roll of the P-47 is considerably better than that of the Mustang, which cannot follow sudden changes in direction. In rate of turn, however, the two aircraft are practically identical.


P-47 Tactical Trials


There are widespread assertions across the web that the squared wing tips gave the P-47N an improved roll rate over the P-47D. It would be nice to see some data that would enable a comparison.

I would also add that a website that Renrich has cited to in the past which is devoted to proving that the F4U-4 was the best fighter bomber of the war states the following about the F4U-4:

The F4U also rolled well. When rolling in conjunction with powerplant torque, in other words, rolling left, it was among the very fastest rolling fighters of the war. In the inventory of American fighters, only the P-47N rolled faster, and only by 6 degrees/second.

http://home.att.net/~historyzone/F4U-4.html

I'm looking at that USAAF evaluation of the P47N. Odd. It is an evaluation of a P-47N that is apparently different than earlier P-47N's. It mentions:

F. Maneuverability and Aerobatics.

Maneuverability and aerobatic characteristics are similar to earlier P-47's in the clean configuration. With wing tip tanks filled the rate of roll and radius of turn of the P-47N is poor. No aerobatics were performed at the high gross weights (wing and belly tanks), but the rate of roll was slow for this condition.

This is odd. Wing tip tanks? The wing tanks were located next to the fuselage.

IV Conclusion

1. Due to the large quantity of fuel it can carry, the P-47N is a good long range fighter-bomber. Although the performance is not too good at high gross weights, it improves as the external fuel is used and by the time the target area is reached it compares favorably to earlier P-47N's.

This seems to indicate that it's performance was different than earlier P-47N's which apparently had better performance. ??? These tests were performed in 1946. Was this a version of the "N" that had wing tip tanks?

 

[DAVIDICUS]

I just came across another interesting account of the vulnerability issue that was discussed earlier starting at Post #263 on this thread.

http://www.ww2aircraft.net/forum/aviation/p-47n-thunderbolt-vs-f4u-4-corsair-superior-738-18.html



From Grant Goodell. He was Skip's, Babis's, and my skipper in VA-741 in the sixties. A great guy, a solid stick and an excellent leader.

I flew both airplanes: about 2500 hours in the F4U 4 including a combat tour in Korea off the Antietam1951-52; about 800 hours in the P 47D as a test pilot. As a prop air superiority fighter I would take the F4U over the P47, more nimble and great rate of climb.

Capt. Brown, RN who flew almost every thing and had more than 2000 carrier landing didn't like the F4U because of high stick forces at very high speeds. You could always pick a Corsair pilot out of the crowd at the bar because of the size of his right bicep. The F6F had a better kill ratio than the F4U because the Hellcat met mostly low time Japanese Army and Navy pilots in 1944 whose favorite defensive maneuver was a Luffberry Circle.

On the other hand the P 47 far outclassed the F4U as a fighter-bomber. The Jug was an absolute terror, carried about the same bomb and rocket load, but had 8 (EIGHT) 50 cal guns. In addition the F4U suffered from having an oil cooler radiator in each leading edge wing root inboard of the gull (check the pics). Any ground fire small arms or expended brass from a plane ahead could penetrate that radiator and in 30 to 40 seconds you had lost oil pressure.

The Navy lost more than 360 F4Us in Korea. more than any other type by far, because of this vulnerability. We lost eight F4Us in our squadron and 2 pilots, both to enemy ground fire. Vought never fixed the problem. On the other hand the AF kept sending P-51s to do ground attack and N Korea was carpeted by 51 aluminum and Rolls 12 cylinder inlines built, as I recall, by Packard. Where were the Jugs?

Grant Goodell

http://www.neptunuslex.com/2009/09/01/f-4u-vs-p-51/

 

[renrich]

Eric Brown, RN was a highly biased observer and absolutely did not like the Corsair. His book, "Duels in the Sky," is filled with incongruent statements about many WW2 aircraft. I and many others on this forum discount much of what he has to say. Ironically, I have read that Eric Brown and Marion Carl were friends and spent a lot of time together. Brown has very little to say good about the Corsair and Carl seemed to think it was a great airplane and, of course, had a lot of experience with it. Oddly I have accounts of pilots flying the Corsair that extoll the virtues of the Corsair's ailerons at high speeds.

 

[DAVIDICUS]

Oddly I have accounts of pilots flying the Corsair that extoll the virtues of the Corsair's ailerons at high speeds.

I don't think it's odd at all. The Corsair is known for being an excellent roller. The P-47 was also known for being an excellent roller.

You said that on the Williams site there is a USAAF evaluation of the P47N which states that the roll rate of the P47N is worse than the earlier models of the P47. I was just pointing out that that account appears to stand by itself as pilot accounts and statements across the web state the opposite.

I have read the testing you are referring to and think I may understand what was meant.

The site says:

IV Conclusion

1. Due to the large quantity of fuel it can carry, the P-47N is a good long range fighter-bomber. Although the performance is not too good at high gross weights, it improves as the external fuel is used and by the time the target area is reached it compares favorably to earlier P-47N's.


Do you see how in this 1946 test its performance was adjudged worse than"earlier P-47N's"? And it also referred to the test plane having "wing tip tanks." Earlier versions of the P-47N, at least those that saw combat, did not have wing tip tanks. I think that when it stated earlier in the test that it rolled slower than earlier "P-47''s", it meant earlier P-47N's just as the above excerpt referred to the test plane performing worse than earlier P-47N's. If the "N" was inadvertently left off and we have all seen lots of typos in these 1940's documents, there is harmonization with literally all other statements and references on the matter.

Just something to think about.

And what do you make of that account that the P-47N rolled faster by 6 degrees over the F4U-4? I know that in the past you have referred to the assertions in that website in support of your arguments.

It's really unfortunate that we don't have source docs on roll rates for may of the planes we discuss which gives rise to all these speculations to begin with.

Lastly, I only posted that last piece that mentioned Brown for an additional reference to the vulnerability issue that plagued the Corsair and the Eric Brown reference did not even touch on that. The Eric Brown reference was confined to:

Capt. Brown, RN who flew almost every thing and had more than 2000 carrier landing didn't like the F4U because of high stick forces at very high speeds. You could always pick a Corsair pilot out of the crowd at the bar because of the size of his right bicep. The F6F had a better kill ratio than the F4U because the Hellcat met mostly low time Japanese Army and Navy pilots in 1944 whose favorite defensive maneuver was a Luffberry Circle.

Do you have any information that counters the vulnerability issue? I think it's reasonable to conclude that it was the oil coolers as opposed to some other system or characteristic but strictly speaking, while we know that the Corsair was about 60% more likely to go down than the Hellcat after actually suffering AA combat damage in a well controlled apples to apples analysis involving some 22,000 sorties, we only have opinions from pilots and others that it was the oli cooling system which was different than the Hellcat and Thunderbolt which shared an identical design except that the Thunderbolt carried significantly more oil.

 

[renrich]

I do not believe that the Corsair was 60 % more vulnerable than the Hellcat to AA fire. It may have been more vulnerable but not to that extent. For my argument on that issue, please go to post # 1233 in the Best WW2 Aircraft. Intuitively, to me, a small target like the oil cooler can't be responsible for that big a difference. I don't believe that the statistical study is valid because there are too many variables. As far as ailerons and high speeds are concerned the F4U1D was ranked second in the Joint Fighter Conference for ailerons at 350 mph, well ahead of the P47D and just behind the P51D. In Dean's book, he states that very high roll rates( about 120 degrees per second at 350 mph IAS) have been claimed for the Corsair and nothing has been found to belie those statements, but no firm data has been found either. That does not sound like stiff ailerons at high speed. Richard Linnekin stated that F4U4 was a" stable airplane with reasonable, not objectionable, control forces." He said it had better control harmony than either the F6F or F8F and that he finally became a decent air to air gunner in the F4U because of it's good control harmony. He also stated that the F4U did not have the "right rudder and right rudder trim deficiencies of the Hellcat." The Corsair could be a problem on takeoff or landing if the 6 degrees right rudder and 6 degrees right wing down aileron trim was not used. As mentioned before, in Dean's book, the P47 was not praised for it's rolling ability. Just to show how valid all this information is, in Bob Johnson's book, "Thunderbolt" he states that the P47 was a much better roller than a Spitfire and he used that rolling ability in mock dogfights with the Spitfire. Go figure.

 

[DAVIDICUS]

I do not believe that the Corsair was 60 % more vulnerable than the Hellcat to AA fire. It may have been more vulnerable but not to that extent.

Yes, well I did say "about 60%." The correct figure is actually 58%.

I don't believe that the statistical study is valid because there are too many variables.

Perhaps you can identify them as you are the one attacking the Naval Air Combat Statistics, and explain why they favored the Hellcat such that the enormous disparity of 58% arose and why they were not washed out by the enormous pool of data collected. To recap, the Navy collected data on 22,000 sorties and found that Corsairs were 58% more likely to be losses from AA fire than Hellcats when actually hit by AA in the same time period, flying from the same ships and flying missions under the "same conditions" in "comparable operations" where the two aircraft received "about the same number of hits per sortie."

And also please offer your thoughts on the coincidence of the following accounts and why, also coincidentally, there does not appear to be a wealth of such accounts with respect to the Hellcat and Thunderbolt which had oil cooling systems that were not just identical but very different than the Corsair's.


From Ron Stout -

"I do recall that the MC [Marine Corps] asked that a F4U version be built for ground attack with the oil cooler relocated to be more immune from ground fire and some additional armor plate. As I remember it was redesignated the AU and also was purchased by the French and designated the F4U-7."
KUNSAN AIR BASE: How It Was - VMF(N)-513 (1951-1954) Page 6 of 9


From Crimson Sky, The Air Battle For Korea, page 67

It was the cruelest kind of fluke. Somewhere on the frozen, snow covered ground below, a Chinese soldier lay on his back, his white quilted uniform making him virtually invisible from the air. As the four Corsairs passed overhead with the throaty roar of their Pratt Whitney engines echoing off the winter landscape, the soldier raised his rifle and pulled the trigger. His comrades did the same, throwing up a hail of bullets around the four blue planes.

What are the chances a rifleman could hit such a speeding target? And even if the tiny .30 caliber bullet did connect with a Corsair, what damage could it possibly do? The F4U-4B was not only heavily armed but armored to protect both pilot and plane from ground fire.

Yet one round hit home, probably hitting the Corsair's Achilles Heel, the oil cooler. ... Less that three minutes after he had been hit, his engine seized and he lost power so fast that he had no chance to make a run for the coast.


From F4U Corsair Units of the Korean War, Page 16

1st Lieutenant Lance "Bud" Yount of VMF-323-

I felt the thud from the round [20mm] as it hit. Suddenly there was a puff of smoke in the cockpit, and I watched my oil pressure drop down to 15psi - normal was approximately 80psi. I yelled out that I'd been hit, and was turning to head south. One of the pilots in my division pulled up alongside me and said that he was going to stay with me, and that I should try to fly the aircraft back to the ship. I dropped a few degrees of flap as he flew under my tail searching for the oil leak. Naturally, with the sharp decrease in oil pressure, I was sure my oil cooler had been hit - it was in a very vulnerable spot.


From Brassey's Ar Combat Reader, Page 174

That decision was coming home to haunt the Corsair pilots. Their airplanes would be hit by nothing more serious than a single rifle bullet, and their engines would seize when all the engine oil leaked from the oil cooler.


From A Revolutionary War: Korea and the Transformation of the Postwar World, Page 138 (Research presented at the Fifteenth Military History Symposium, held at the United States Air force Academy, 14-16 October 1992)

The Corsair, an air cooled radial engine aircraft, might have been expected to have a higher survivability than the Air Force's liquid cooled (and hence vulnerable) F-51 Mustang. In fact, insufficient oil cooler and engine protection rendered the Corsair just as susceptible as the Mustang to ground fire.


From Grant Goodell

In addition the F4U suffered from having an oil cooler radiator in each leading edge wing root inboard of the gull (check the pics). Any ground fire small arms or expended brass from a plane ahead could penetrate that radiator and in 30 to 40 seconds you had lost oil pressure.

The Navy lost more than 360 F4Us in Korea. more than any other type by far, because of this vulnerability. We lost eight F4Us in our squadron and 2 pilots, both to enemy ground fire. Vought never fixed the problem. On the other hand the AF kept sending P-51s to do ground attack and N Korea was carpeted by 51 aluminum and Rolls 12 cylinder inlines built, as I recall, by Packard. Where were the Jugs?
F4-U vs P-51 « Neptunus Lex


I don't wish to rehash this whole discussion again. I can't imagine offering anything other than has already been analyzed and discussed at length on the subject of the Corsair's enormous vulnerability to damage from ground fire. I will add the following observation though: We have more controlled data to support the enormous disparity in vulnerability between the Corsair and Hellcat than to support any disparity existing at all between the Mustang and Thunderbolt. I also can't help but think that if the disparity between the Corsair and Hellcat were reversed such that the Hellcat were established to be 58% more vulnerable to ground fire, that you would just add that statistic as another feather in the Corsair's cap.

For other forum members, see the discussion beginning at Post #263:
http://www.ww2aircraft.net/forum/aviation/p-47n-thunderbolt-vs-f4u-4-corsair-superior-738-18.html

I don't know what to make of all the roll rate discrepancies. As I already indicated, it would be nice to have some data for both aircraft so that we are not piecing together speculations. I find it interesting what Robert Johnson said about outrolling the Spitfire as it may have some support in the P-47C tactical trials against the Spitfire Mk. 9. (We don't know which version Spitfire he was sparring with.)

 

[davparlr]

Very interesting site on Jack Payne, P-47 pilot. Almost seems unreal, but there are pictures . Maybe this has been referenced before.

Me Fahdda

 

[renrich]

I believe we do have data on rates of roll of US fighters. Page 602 in Dean has an article and graph from NACA TR868 and Perkins and Hage(whatever that is) Also as far as roll rate is concerned, on the Williams site there is a comparison between FW190(that was supposed to be a premier roller) and F4U1 and F6F3. It stated that the FW rolled with great ease, EQUAL to the F4U and better than the F6F.

On the oil cooler issue, I am merely giving an opinion and am not trying to win points in any debate. Also trying a little common sense and I believe there is at least one other member on this site,(whose opinion I highly value) who shares my opinion about the so called statistical study and the 58% number. Too many variables to be valid. A for instance, to me, is the majority of all air to ground missions in F4Us were flown by Marine pilots. Do Marines press attacks closer than USN pilots? I suspect that they do. I can't prove it! In the Naval Aviation Combat Statistics there is mention of the fact that the vast majority of air to ground missions in the Phillipines were flown by F4Us and they did good work.

We do have some facts to go by. Hellcats dropped 6503 tons of munitions in the PTO and had 553 losses to AA. Corsairs dropped more than twice the number of munitions, 15621 tons, and had 349 AA losses. I know, I know, the Corsairs were dropping bombs on islands with few Japs in residence and only a few bathing beauties on the beach. Still those numbers seem significant to me. How many Corsair bombs were dropped on bathing beauties and how many on mad Japs in the Phillipines where the Hellcat was absent. To me, in 64051 combat sorties flown by F4Us, to lose only 349 to AA and 189 to EA does not indicate a lot of vulnerability. The Hellcat lost a good many more in almost the same number of sorties against probably less competent Japanese pilots. We also have the fact that the USN picked the F4U1D over the F6F5. There are lies, damn lies and statistics. Facts, common sense and intuition go a long way with me. It is common sense that the oil cooler in the Hellcat or P47 was less vulnerable to ground fire or air to air fire than that of the F4U. 58% or whatever in that range I don't believe.

 

[DAVIDICUS]

I believe we do have data on rates of roll of US fighters. Page 602 in Dean has an article and graph from NACA TR868 and Perkins and Hage(whatever that is)

I don't have Dean's book. So what is the roll rate between the P-47N and F4U-4? This discussion arose regarding those two planes.

Too many variables to be valid. A for instance, to me, is the majority of all air to ground missions in F4Us were flown by Marine pilots. Do Marines press attacks closer than USN pilots? I suspect that they do. I can't prove it!

We already addressed this earlier in the thread. If this thesis had merit, then we would not see "about the same number of hits per sortie" as between the two aircraft. JoeB stated the following:

"The figures are damaged suffered and losses per sortie encountering AA. So it should basically correct for mission profile differences. It wouldn't include pure air to air sorties, nor total milk run ground attack sorties. And 1945 carrier sorties only, so cuts out a lot USMC operations on Okinawa (which I doubt was heaviest AA loss environment anyway, that would probably have been going after airfields in Japan, as it had similarly been in ETO). And as mentioned already stats are given for both a/c damaged and lost, and rate of damage was similar, undercutting any assumption of a hidden difference in average mission profile or tactics between the two types on 'sorties encountering AA'. The main difference was % of a/c hit by AA which didn't make it back, which was much higher for the F4U, and that's actually the succinct point made in the notes to the NASC table, as quoted above."

I also gave you another startling stat earlier in the thread. For all carrier operations, for the entire war, Navy pilots (just Navy pilots) lost Corsairs in combat at a rate 66% higher than Navy Pilots (just Navy pilots) lost Hellcats.

We do have some facts to go by. Hellcats dropped 6503 tons of munitions in the PTO and had 553 losses to AA. Corsairs dropped more than twice the number of munitions, 15621 tons, and had 349 AA losses. I know, I know, the Corsairs were dropping bombs on islands with few Japs in residence and only a few bathing beauties on the beach. Still those numbers seem significant to me.

So if I understand you correctly, you want to ditch the Naval Air Combat Statistics controlled data for the same time period, flying from the same ships and flying missions under the "same conditions" in "comparable operations" where the two aircraft received "about the same number of hits per sortie" because there are too many uncontrolled for variables and instead adopt the metrics you cite above as evidence regarding Corsair vulnerability to AA fire?

Facts, common sense and intuition go a long way with me.

On the first two, you and I will just have to agree to disagree.

 

[renrich]

Because the graph is small the following is subject to error caused by the width of the pencil lead but the F4U1D has only a limited range of performance in the graph and it is a straight line at around 45 degrees ranging from a roll rate of 75 degrees per second at 240 mph IAS to 90 degrees per second at 290 mph IAS. The P47C-1 has a roll rate ranging upward from 59 degrees per second at 160 mph IAS to 82 degrees per second at 240 mph, where it begins to drop rather rapidly at about a 30 degree angle where for example it's roll rate at 350 mph IAS is only about 72 degrees per second. Contrast that with reported roll rates for the Corsair at 350 mph IAS of 120 degrees per second. Apparently, according to Dean, a roll rate resulting in a four second 360 degree roll was good performance for a WW2 fighter.
Going back to the accursed oil cooler, on page 80 of the NACS report there is a table showing, among other things the % lost of planes hit by AA fire in the whole war. This would be a much larger sample and would to me be a much more accurate indicator of the relative vulnerability of the various types and would also seem to fit well with common sense judgment of relative vulnerability based on looking at the location of the oil coolers IMO. The authors declare that this table distorts the relationships between planes and that is probably true when looking at AA losses per 100 action sorties, planes hit per 100 attacks AA present and AA losses per 100 attacks AA present. But I don't believe it distorts the relationship between types when looking at % lost of planes hit. A hit is a hit whether in 1943, 44 or 45 and whether flown by USN or Marine pilots. The table shows that 24 % of Hellcats that were hit were lost. 29 % of Corsairs hit were lost and 27% of FMs hit were lost. My opinion is that those ratios, intuitively reflect the difference in vulnerability caused probably by the location of the oil cooler. I don't believe that difference rises to the 58% level. Perhaps more interesting is that only 12 % of SBDs hit were lost and 27% of the SB2Cs hit were lost. Another interesting point subject to our learned interpretation is that the SBDs and Corsairs were more likely to have been used in land based operations where as the Hellcats were more likely to have been carrier based. A factor to be considered also is whether the aircraft shot down by AA were going against AA fire from ships or from ground based AA. The report does not seem to make that distinction. Beyond all this I am absolutely good with agreeing to disagree.

Regarding the relative effectiveness and vulnerability in combat, A Hellcat was lost to EA action for every 25.83 combat sorties whereas a Corsair was lost to EA action for every 17.46 combat sorties which seems to favor the Hellcat, but the Corsair was in action in the Solomons in February 1943 against some still well trained IJN pilots. The Hellcat did not go into action until August of that year and by then the Japanese pilot erosion had become well advanced. The fact still remains that the Navy decided the Corsair was more useful than the Hellcat and there are countless comparisons between performance of the two and the Corsair is always superior.

 

[DAVIDICUS]

On page 80 of the NACS report there is a table showing, among other things the % lost of planes hit by AA fire in the whole war. This would be a much larger sample and would to me be a much more accurate indicator of the relative vulnerability of the various types and would also seem to fit well with common sense judgment of relative vulnerability based on looking at the location of the oil coolers IMO.

The whole war? And this would satisfy your concern about too many unaccounted for variables such that you would accept it over the Naval Air Combat Statistics data on what you see as an insufficient 22,000 sorties for just carrier operations between the Corsair and Hellcat for the same time period, flying from the same ships and flying missions under the "same conditions" in "comparable operations" where the two aircraft received "about the same number of hits per sortie"?

Please. That's like pouring gasoline on a fire out of concern that the fire might get larger. The more uncontrolled variables the better if it will whittle that 58% down ... right?

The fact still remains that the Navy decided the Corsair was more useful than the Hellcat and there are countless comparisons between performance of the two and the Corsair is always superior.

Did it decide this before or after the Navy's analysis in the NACS? It would appear that the problem was severe enough that even with that wide margin of performance superiority, the Navy, in mid 1946, concluded the following from an analysis of 22,000 sorties of carrier operations between the Corsair and Hellcat for the same time period, flying from the same ships and flying missions under the "same conditions" in "comparable operations" where the two aircraft received "about the same number of hits per sortie."

From Naval Aviation Combat Statistics, WWII

Page 58:

Thus comparisons are valid between the carrier F6F and F4U totals because they generally operated from the same ships during the same period.
...
Certain tentative conclusions may be reached from these two tables:

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

And on Page 79, Note (e) to Table 29

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.


As for the roll rates between the F4U-4 and P-47N, you have offered no compelling comparative data (or any comparative data at all for that matter) that supports the F4U-4 over the P-47N. Both are widely reported to have been excellent rollers. It must be possible to generate a valid analysis of the issue with computer modeling. Unless we find test docs, we will have to wait for someone to generate valid manufactured conclusions.

 

[renrich]

Some folks love to talk percentages. 77% of Corsair's air to air kills were fighters. 71% of Hellcat's were fighters. I read that as Corsair was up against more dangerous opponents more often. Impossible to believe that the USN and it's pilots did not know about the Corsair's supposed vulnerability caused by the , TaDa, oil cooler, before the statistical study came out after the war. This vulnerability on this forum appears to me to be in the same category as one of those, "Oh boy, look what I found," deals. As mentioned before the oil cooler in the leading edge of the port wing root , (apparently located in exactly the same location in the Sea Fury) was pretty small, around 12"-18" by 12"-18" and TaDa could be damaged by a rifle bullet. There was a much larger component of the aircraft, and much more important, which could be damaged by a rifle bullet and every fighter in the world had one. That component was the pilot. Which was more likely to be damaged or put totally out of action by the nefarious rifle bullet or a 12.7. 25 mm, or 37 mm round. I submit that the pilot was the one I would worry about. Fact-----Hellcat flew 66530 sorties and had 823 lost to combat. Corsair flew 64051 sorties and had 459 lost to combat. Both seem pretty rugged to me.

Back to the F4U4 V P47N discussion. I suppose I have not proved that the P47N was an inferior roller although from what I have read, the P47s generally were not noted as great rollers(Holy Rollers?) and F4Us were. I am no engineer but I have a hard time understanding how one takes an airplane which did not have great roll rates, extend the wing span and get a better roller. Seems like it would work in the opposite way. There I go with the common sense thing again. The FAA clipped the wings of the Corsair, ( so they would fit in their low overhead hangar decks) and it was said the roll rate increased, (and the stall speed went up.) Intuitively(bad word) that makes sense. Oh well, so much for the roll rate of the two.

By late WW2, fighter were increasingly used in the fighter bomber role. At SL, the F4U4 could do 380 MPH and the P47N could get 365 MPH, both in combat power, according to Dean. The F4U4 was faster than or equal to the P47N all the way to 25000 feet where it began to lose ground. Almost all ACM and every bit of air to ground business took place below 25000 feet. The takeoff distance from an airfield for the F4U1D was 840 feet and for the P47C was 2220 feet, according to Dean. Seems like that would be an advantage for Corsair since forward air fields could be short. That disparity in takeoff difference was probably greater for the F4U4 over the P47N, unless the P47N was not carrying much fuel.
Last point, (every one says "thank goodness") The F4U4, unless I am mistaken was designed for, could and did operate from carriers. The P47N...(are you kidding?) Seems to me that the P47N would be useful as a long range high altitude escort fighter but the F4U4 was more useful in all other roles. End of story!

 

[Clay_Allison]

Some folks love to talk percentages. 77% of Corsair's air to air kills were fighters. 71% of Hellcat's were fighters. I read that as Corsair was up against more dangerous opponents more often. Impossible to believe that the USN and it's pilots did not know about the Corsair's supposed vulnerability caused by the , TaDa, oil cooler, before the statistical study came out after the war. This vulnerability on this forum appears to me to be in the same category as one of those, "Oh boy, look what I found," deals. As mentioned before the oil cooler in the leading edge of the port wing root , (apparently located in exactly the same location in the Sea Fury) was pretty small, around 12"-18" by 12"-18" and TaDa could be damaged by a rifle bullet. There was a much larger component of the aircraft, and much more important, which could be damaged by a rifle bullet and every fighter in the world had one. That component was the pilot. Which was more likely to be damaged or put totally out of action by the nefarious rifle bullet or a 12.7. 25 mm, or 37 mm round. I submit that the pilot was the one I would worry about. Fact-----Hellcat flew 66530 sorties and had 823 lost to combat. Corsair flew 64051 sorties and had 459 lost to combat. Both seem pretty rugged to me.

Back to the F4U4 V P47N discussion. I suppose I have not proved that the P47N was an inferior roller although from what I have read, the P47s generally were not noted as great rollers(Holy Rollers?) and F4Us were. I am no engineer but I have a hard time understanding how one takes an airplane which did not have great roll rates, extend the wing span and get a better roller. Seems like it would work in the opposite way. There I go with the common sense thing again. The FAA clipped the wings of the Corsair, ( so they would fit in their low overhead hangar decks) and it was said the roll rate increased, (and the stall speed went up.) Intuitively(bad word) that makes sense. Oh well, so much for the roll rate of the two.

By late WW2, fighter were increasingly used in the fighter bomber role. At SL, the F4U4 could do 380 MPH and the P47N could get 365 MPH, both in combat power, according to Dean. The F4U4 was faster than or equal to the P47N all the way to 25000 feet where it began to lose ground. Almost all ACM and every bit of air to ground business took place below 25000 feet. The takeoff distance from an airfield for the F4U1D was 840 feet and for the P47C was 2220 feet, according to Dean. Seems like that would be an advantage for Corsair since forward air fields could be short. That disparity in takeoff difference was probably greater for the F4U4 over the P47N, unless the P47N was not carrying much fuel.
Last point, (every one says "thank goodness") The F4U4, unless I am mistaken was designed for, could and did operate from carriers. The P47N...(are you kidding?) Seems to me that the P47N would be useful as a long range high altitude escort fighter but the F4U4 was more useful in all other roles. End of story!

I'm still not convinced that a highly documented vulnerability on the F4U to ground fire can be cavalierly dismissed as you want it to be.

The main problem I have with the P-47 is that it was too expensive for ground attack. An un-turbo A-47 would have been an interesting dedicated fighter bomber but that's outside of the scope of the discussion.

 

[DAVIDICUS]

Impossible to believe that the USN and it's pilots did not know about the Corsair's supposed vulnerability caused by the , TaDa, oil cooler, before the statistical study came out after the war.

Perhaps a review of this thread would be helpful. As I earlier said, "I for one do not find it hard to believe that the fog of ongoing war would obscure the vulnerability of the Corsair. Especially when probably no one was looking at loss rates under comparable circumstances or probably comparative loss rates at all. After all, both aircraft were very sturdy, shared the R-2800 engine and were similarly unbelievably successful against their Japanese opponents."

And as JoeB said, "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)."

[F]rom what I have read, the P47s generally were not noted as great rollers(Holy Rollers?) and F4Us were.

??? You're kidding right? There are references all over the web, in books and by pilots about the excellent roll ability of the P-47 and with the exception of that one piece on the Spitfire Performance site, the consensus is that the P-47 with it's larger wing, larger ailerons and squared wing tips had better roll than the "D". That is not to say that the Corsair wasn't also an excellent roller as well.

By late WW2, fighter were increasingly used in the fighter bomber role. At SL, the F4U4 could do 380 MPH and the P47N could get 365 MPH, both in combat power, according to Dean. The F4U4 was faster than or equal to the P47N all the way to 25000 feet where it began to lose ground. Almost all ACM and every bit of air to ground business took place below 25000 feet. The takeoff distance from an airfield for the F4U1D was 840 feet and for the P47C was 2220 feet, according to Dean. Seems like that would be an advantage for Corsair since forward air fields could be short. That disparity in takeoff difference was probably greater for the F4U4 over the P47N, unless the P47N was not carrying much fuel. Last point, (every one says "thank goodness") The F4U4, unless I am mistaken was designed for, could and did operate from carriers. The P47N...(are you kidding?) Seems to me that the P47N would be useful as a long range high altitude escort fighter but the F4U4 was more useful in all other roles. End of story!

I am a bit confused as to what this has to do with roll rates between the P-47N and F4U-4 or the documented enormous vulnerability of the Corsair to AA fire. Is this a "switch the subject to something that I can defend about the Corsair" tactic? I frankly don't have any desire to check on those performance stats that you have offered or cross check them against other sources.

At any rate, I will conclude with something else I posted earlier on this thread:

"Lets say we have two contemporary aircraft that appear to perform similarly in the air to ground role. If it came to your attention that one of those aircraft was 58% more likely to be lost from anti-aircraft fire than the other when actually hit by anti-aircraft fire during the same time period, flying from the same ships and flying missions under the "same conditions" in "comparable operations" where both aircraft received "about the same number of hits per sortie," would you classify the aircraft that's 58% more likely not to return, leave its pilot dead, behind enemy lines or just somewhere in the water or on the ground as unsuitable in that role?

Put differently, if you could reasonably anticipate losing 16 of one type of aircraft for every 10 of the other type under the apples to apples comparison above, would that move you to declare one of those aircraft as unsuitable? What about if you are a pilot? Do you think you might summarily conclude that one of those aircraft is simply unsuitable in that roll?

There is a certain elasticity to language that often results in disagreements over characterizations. Can we agree that if you were a pilot and were expected to pound defended targets and had a choice between flying a Corsair or Hellcat and knew about the 16:10 loss ratio that you would refuse to go near a Corsair with a 10 foot pole?"

END OF STORY

 

[renrich]

I doubt we will agree on anything having to do with the Hellcat Corsair discussion. I believe the Navy picked the right horse. The thread is supposed to be about P47N and F4U4. For the purposes of late WW2, the F4U4 is the better AC, IMO. I suggest you get a copy of Dean and perhaps your viewpoint will change but at least your viewpoint will be made wider and you will have a lot of fun reading it. It is a truly good book.

 

[DAVIDICUS]

I suggest you get a copy of Dean and perhaps your viewpoint will change

Somehow I don't think Dean's book will cause me to reject the enormity of relevant well controlled data which is set out and analyzed in the Naval Air Combat Statistics.

For the purposes of late WW2, the F4U4 is the better AC, IMO.

I think they were designed with different roles. The P-47N, for instance, was designed to be an extreme range high altitude escort. As was discovered after the war, in the air to ground role, the Corsair was determined to have a fragile glass jaw when compared to the Hellcat. In my opinion, there is no reason to believe that this enormous disparity in vulnerability between the Corsair and Hellcat would not have likewise existed between the F4U-4 and P-47N. In addition, while the Hellcat and Corsair both had 18 gallon oil tanks, the P-47N's oil tank was 40 gallons. Even the P-47D had a 28.7 gallon oil tank which may have contributed to one of its nicknames, "The Unbreakable."

 

[DAVIDICUS]

Pilot Edwin L. King with flak damaged P-47 at Pisa following Silver Star mission of 12 Jan. 1945. Aircraft is 7D3 42-29300. Crew Chief H.D. (Henry) Embry was the photographer of the shot seen many times of the oil-soaked Jug that returned to base after having two jugs shot off during a sortie (pilot Ed King). Embry says that after the shot was taken, his camera was stolen and he had never seen the shot until after the war and many years hence.

 

[Messy1]

Wow, that looks like that was a exciting ride!

 

[DAVIDICUS]

I bet it's even more exciting if you're only carrying 18 gallons of paint.

That additional 10+ gallons (P-47D) or additional 22 gallons (P-47N) can come in handy when trying to get back home.

 

[Colin1]

How often did R28s throw their oil like that?
I heard they were damned reliable and barely seeped oil, let alone threw it.