F6F Hellcat vs. P-47 Thunderbolt

I agree with your point about exaggeration but see its value more as further corroboration of the vulnerability due to oil cooling design issue. It would appear that not all recip oil cooling design layouts were equally vulnerable.

Magister said:

I agree with your point about exaggeration but see its value more as further corroboration of the vulnerability due to oil cooling design issue. It would appear that not all recip oil cooling design layouts were equally vulnerable.

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It might help if you had a notion which layout was more vulnerable and why?

The following post has some interesting discussion. What do you think Bill? Do you think there might be another cause of the vulnerability of the Corsair that was noted by the USN?

http://www.ww2aircraft.net/forum/aviation/hardest-plane-take-down-ww2-3114-15.html

Post #214

The other R-2800 powered fighters do not have these interesting tidbits inserted into the pilots manuals.

The Pilots Flight Operating Instructions for the F4U-4 (October 1944 T.O. No. AN-01-45HB1) warned that there was only enough oil for a maximum of ten seconds of inverted flight. Also, where there was damage to an oil cooler with resulting loss of oil, neither the oil pressure gauge nor the oil temperature gauge would register the change in pressure or temperature until all of the oil was out of the system. (See Manual at page 10) Pilots were warned during combat to check the oil coolers and trailing edges of the wings often for damage that could prove catastrophic.

I have checked the pilots manuals for the P-47 and Hellcat and no such caveats or warnings are present. Nor have I ever heard of any noteworthy vulnerability of the oil cooling systems for either.

As JoeB has pointed out, the oil cooler vulnerability issue is further supported by reports from those who fought in Korea. I have been reading various references to the vulnerability of the oil coolers in Corsairs elsewhere on the web (as I am sure you have) as well.

Post # 216, same thread

The author, Walter Boyne, mentions that with respect to operations in Korea, the oil cooler in the Corsair was vulnerable to even small arms fire.

"The airplanes would be hit by nothing more serious than a singe rifle bullet, and then their engines would seize when all the engine oil leaked from the oil cooler. They would then be forced to land behind enemy lines minutes after being hit. ... We were losing many F4U pilots and hoped they were being captured, not killed out of hand" (Page 174)

The Corsair being 57% more likely to be brought down would certainly qualify the Hellcat as having a "considerable advantage." I cut and pasted this from that thread as well.


Page 79, Note (e) to Table 29 of Naval Aviation Combat Statistics, WWII:

(e) 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.

In WW2, the F4U flew 64051 sorties, dropped 15621 tons of bombs and lost 349 AC to AA. The F6F flew 66530 sorties, dropped 6503 tons of bombs and lost 553 AC to AA. Statistically it seems like the Corsair is a lot more durable in the bomber role. Now maybe the Corsair carried a huge load of bombs and the Hellcat carried a lot less. Maybe the F4Us bombed where there was no AA( and no rifles) and the Hellcat bombed where there was a lot. The Wildcat had an oil cooler in a similar position as the Corsair and we hear little about it's vulnerability. The USN in 1944 decided the Corsair was a better carrier plane and declared the Hellcat should be replaced as soon as possible. I wonder if the USN knew about the infamous oil cooler of the Corsair. Perhaps the Corsair was picked because it could dive bomb and the Hellcat(nor the P47) could not.

The USN in 1944 decided the Corsair was a better carrier plane

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The Corsair was inheritly superior as a fighter aircraft. I suspect that was considered more important then the higher price tag and oil cooler vulnerability.

Clay_Allison said:

Just realized that the P-47 was more than twice as expensive as the F6F; owning, no doubt, to the complex and expensive turbocharger (as opposed to the Supercharger on the F6F).

F6F: $35,000 in 1945
P-51: $50,985 in 1945
P-47: $85,000 in 1945
P-38: $97,147 in 1944

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The F6F price is not directly comparable. The often quoted F6F price (starting from $50,000 and dropping to $35,000 by the end of the production run) did not include the so called "Government Furnished Equipment", like engines, propellers, wheels, brakes, tires and tubes, auxiliary power plant, radio receivers and transmitters, starters, batteries, generators.

"American Hundred Thousand" gives a price for F4U of $75,000 (1944). That is likely the total price. Still the F6F was cheaper than the F4U and P-47, though.

"Wildcat had an oil cooler in a similar position as the Corsair and we hear little about it's vulnerability."

I don't know. I have seen diagrams of the Hellcat's and Corsair's and they are very different. I have not seen a diagram the layout for the Wildcat.

We just don't have hard data between the Wildcat and other Naval fighters flown under what the Navy described as the "same conditions" in the same operations, at the same time and off of the same ships to compare losses where actual AA fire was suffered.

Up until recently, I had not heard about survivability issues with the Corsair. It would appear that not having heard about the 26% Hellcat loss rate vs. 41% Corsair loss rate under what the Navy stated were the "same conditions" does not mean that this 57% increased likelihood of being brought down did not exist.

The Corsair was a great plane despite any survivability issues acknowledged by the USN. It's contributions to the war effort were enormous. Keep in mind that it took an enormous 57% increased likelihood of being brought down to move the Hellcat's evaluation to "slightly superior" in combat.

As for why the USN or USAAF made the production decisions they did, all I can say is that they did not always act in accordance with principles of cost efficiency or effectiveness. You yourself mentioned earlier that for the ETO, the USAAF should have gone with the Corsair over the Thunderbolt and Mustang. Are you now asserting that the fact that they didn't is evidence that such a decision would have been a poor one?

Do you think it may be possible that the Navy's data compilation and analysis of all that data may have occurred after the war? In similar fashion and in hindsight you and some others have stated that the Corsair should have been adopted by the USAAF in the ETO. These sorts of could have, should have, would have analysis and conclusions invariably always take place well after the fact and always clash with the decisions that were actually made. As such, the fact that different decisions were actually made would not be evidence that the after the fact analysis and conclusions are faulty.

I understand that later post WWII variants of the Corsair did modify the oil cooler design as a result of what was perceived to be problematic systemic vulnerability.

"Wildcat had an oil cooler in a similar position as the Corsair and we hear little about it's vulnerability."

I don't know. I have seen diagrams of the Hellcat's and Corsair's and they are very different. I have not seen a diagram the layout for the Wildcat.

We just don't have hard data between the Wildcat and other Naval fighters flown under what the Navy described as the "same conditions" in the same operations, at the same time and off of the same ships to compare losses where actual AA fire was suffered.

Up until recently, I had not heard about survivability issues with the Corsair. It would appear that not having heard about the 26% Hellcat loss rate vs. 41% Corsair loss rate under what the Navy stated were the "same conditions" does not mean that this 57% increased likelihood of being brought down did not exist.

The Corsair was a great plane despite the serious survivability issues acknowledged by the USN. It's contributions to the war effort were enormous. Keep in mind that it took an enormous 57% increased likelihood of being brought down to move the Hellcat's evaluation to "slightly superior" in combat.

As for why the USN or USAAF made the production decisions they did, all I can say is that they did not always act in accordance with principles of cost efficiency or effectiveness. You yourself mentioned earlier that for the ETO, the USAAF should have gone with the Corsair over the Thunderbolt and Mustang. Are you now asserting that the fact that they didn't is evidence that such a decision would have been a poor one?

Do you think it may be possible that the Navy's data compilation and analysis of all that data may have occurred after the war? In similar fashion and in hindsight you and some others have stated that the Corsair should have been adopted by the USAAF in the ETO. These sorts of could have, should have, would have analysis and conclusions invariably always take place well after the fact and always clash with the decisions that were actually made. As such, the fact that different decisions were actually made would not be evidence that the after the fact analysis and conclusions are faulty.

I understand that later post WWII variants of the Corsair did modify the oil cooler design as a result of what was perceived to be problematic systemic vulnerability.

Incidentally, the Thunderbolt could and did dive bomb. I have a P-47 maual that has an entire section devoted to dive bombing.

---------------------------------------------------------------------

Major Hal Shook, CO 506th F.S. 404th F.G. 9th AF ,Winkton, D-Day 1944.
This P-47 Thunderbolt was flown by Major Hal Shook prior to and throughout the days after D-Day, what follows is his account of several of his actions.



In the summer of 1944, we were flying near the Seine River, trying to stop the German Army from crossing over and regrouping on the other side. Crossing points along the river were under constant aerial attack and were heavily defended with anti aircraft guns. Approaching the river, we ran into heavy flak, ugly black puffs of smoke so thick it looked like you could walk on it. We were dodging and changing altitude trying to outguess the gunners, when we saw five barges on the water, 10,000 feet below. They were heavily loaded with enemy equipment and troops.
As I rolled into my dive bomb run, almost straight down, my P47 Thunderbolt shuddered as heavy shrapnel slammed into the propeller and engine. Oil streamed out to cover my windscreen ... Bobbing and Jigging from side to side, and with oil still blowing back. I pulled up and away from the river and the flak. Miraculously, the engine was still running. It carried me to an emergency landing strip in Normandy.

Whoa, I have never said that the F4U should have been chosen over the Mustang and P47. I have said that if the US could have only built one fighter, it would have had to be the Corsair and I do think that the Corsair if adapted to AAF use would have been a better choice than the Jug. The Corsair could never have fulfilled the long range escort mission of the P51. Ideally IMO the US would have built two fighters only, Corsair and Mustang. All effort being expended on them would have made them both better AC. Kind of like although not strictly analogous to 109 and 190. My suspicion is that what the pilot is calling a dive bombing run was really a glide bombing run. I don't believe the P47 had dive brakes and if it was put into an 85 or 90 degree dive it would have not been able to bomb accurately. The Corsair was found to have better accuracy dive bombing than the SB2C and almost as good as the Dauntless. My mistake on the oil cooler of the F4F. I just looked it up in Dean and it is located low and behind the engine. I was talking from memory and thinking of Wildcat pilots saying they were hit in the wing and the oil cooler was punctured.

There are different ways to solve the same problem. The USAAF could purchase the F4U ILO the P-38, P-40, P-47 and P-51 beginning in early 1943. However the P-51 with Packard Merlin engine was relatively effective and inexpensive. I would prefer to purchase the P-51B beginning in early 1943 for the air superiority role plus the F6F for use as a fighter-bomber. The obsolecent P-40 and problem plagued (not to mention expensive) P-38 end production. The P-47 becomes just another prototype that never enters mass production.

Meanwhile the USN and USMC get the Corsair as happened historically. They don't need as many aircraft as the USAAF so the high price tag isn't as big an issue.

renrich said:

Whoa, I have never said that the F4U should have been chosen over the Mustang and P47. I have said that if the US could have only built one fighter, it would have had to be the Corsair and I do think that the Corsair if adapted to AAF use would have been a better choice than the Jug. The Corsair could never have fulfilled the long range escort mission of the P51. Ideally IMO the US would have built two fighters only, Corsair and Mustang. All effort being expended on them would have made them both better AC. Kind of like although not strictly analogous to 109 and 190. My suspicion is that what the pilot is calling a dive bombing run was really a glide bombing run. I don't believe the P47 had dive brakes and if it was put into an 85 or 90 degree dive it would have not been able to bomb accurately. The Corsair was found to have better accuracy dive bombing than the SB2C and almost as good as the Dauntless. My mistake on the oil cooler of the F4F. I just looked it up in Dean and it is located low and behind the engine. I was talking from memory and thinking of Wildcat pilots saying they were hit in the wing and the oil cooler was punctured.

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If it was just going to be two, I'd say the Mustang and Hellcat, taking into account the production qualities, costs, aforementioned Corsair sensitivity to ground fire, and takeoff and landing characteristics. The F4U was a bit of a widowmaker on the ground. The Hellcat was easy to fly, easy to land.

Renrich, he did say "almost straight down." Were you there? Later models of the P-47 (I think D-28 or maybe 30) had dive brakes. You may be correct about "glide bombing" as the Thunderbolt accelerated very quickly in a dive and had a higher dive speed than the Corsair. This valuable air combat characteristic would probably be less than ideal for 60 degree bombing angles. At any rate, you don't need to be at 85 or 90 degrees to dive bomb. Anything 60 degrees or more would technically qualify.

Interesting information about the dive bombing accuracy of the Corsair. Do you have a source?

I notice that the Joint Fighter Conference Summary of Questionnaires presents the following:

The Division of Votes for the Summary was:

Army 9
Navy 15
British 7
Contractors 20

Note that the Navy votes outnumbered the Army by 40%. We do not know the breakdown of the 20 contractors who voted in the Summary but we do know that Chance Vought contractors outnumbered the Republic contractors at the conference by 320%.

Fighter Appearing to Have the Best Stability and Control in a Dive

(1) F4U-1 -- 25%

(2) P-47 -- 23%

(3) F6F -- 13%

.....I would prefer to purchase the P-51B beginning in early 1943 for the air superiority role plus the F6F for use as a fighter-bomber. ......P-38 end production. ....

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If the AAF had thrown full support and priority to the P38 in 1939 and 1940, it would have been in full production by the time of Pearl Harbor.

Imagine P38's actually doing deep penetration missions into Germany early in 1943.

Same with the Hellcat being on the drawing boards after hearing about the AVG experiences with the IJA/IJN fighters early on.

syscom3 said:

If the AAF had thrown full support and priority to the P38 in 1939 and 1940, it would have been in full production by the time of Pearl Harbor.

Imagine P38's actually doing deep penetration missions into Germany early in 1943.

Same with the Hellcat being on the drawing boards after hearing about the AVG experiences with the IJA/IJN fighters early on.

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Full support would have required some serious development of the engine mountings. IIRC the 38 had serious issues in the ETO. If that was fixed, The P-38 would have been a great all-rounder until the P-51 started doing the same job for half as much cost per unit later in the war.

Clay_Allison said:

Full support would have required some serious development of the engine mountings. IIRC the 38 had serious issues in the ETO. If that was fixed, The P-38 would have been a great all-rounder until the P-51 started doing the same job for half as much cost per unit later in the war.

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The P38's in the MTO didnt have many problems.

P38's used in the recon role (F4 and F5) were in production and in use, and didnt have many issues.

P38's used up in Alaska by the 11th AF also didnt have many problems.

Although this should be the subject of a different thread, If the AAF threw all of their resources at the P38 problems that surfaced in 1940 and 1941, then the axis would be at a disadvantage in Jan 1942 onwards.

pg 519, Dean, "America's Hundred Thousand," March 18, 44, "The Corsair is first used as a dive bomber, it is found that the AC can be used safely in dives up to an angle of 85 degrees." Pg 80, "Corsair," by Barrett Tillman, " In other words the SBD-- designed and built as a dive bomber-- was barely 10% more efficient in that esoteric role than the F4U." This was based on a comparison of results between 3 squadrons of Marine F4Us and 3 squadrons of Marine SBDs. Also, in Tillman's book on SBDs, pg 180, he states that Corsairs replaced SBDs as the fleet dive bombers. The SB2C was considered as not as accurate as the SBD and was somewhat of a failure. I can't find the exact source of the comparison between Corsair, Dauntless and Helldiver, most of my books are packed but I will continue to search. The problem with any fighter dive bombing without dive brakes and the P47 had the reputation of losing altitude very quickly when pointed down is that the faster you go, the harder to make fine adjustments and the faster you are the sooner you have to pull out before making ground to metal contact. I don't believe the Jug was ever as effective as the Corsair as a dive bomber.

"Corsair," by Barrett Tillman, " In other words the SBD-- designed and built as a dive bomber-- was barely 10% more efficient in that esoteric role than the F4U." This was based on a comparison of results between 3 squadrons of Marine F4Us and 3 squadrons of Marine SBDs.

How did they measure "efficiency"? What exactly is the data of results from the two groups of three squadrons? Is this a large enough sample? Is this really an apples to apples comparison? How do we know? Did they operate under the same conditions, against the same targets in the same time frame with presumably the same defensive interference from the enemy?

If the massive Corsair loss rate over the Hellcat had been asserted on the basis of two groups of three squadrons, with a summary conclusion about the Corsair's relative vulnerability, do you think you might be wondering the same thing? Moreover, if the data about the Corsairs v. Hellcats could not be analyzed on the same basis, do you think you would just accept the conclusion about the Corsair's vulnerability compared to the Hellcat? I think we both know that you would argue very hard against such a conclusion.

Why are you accepting the conclusions regarding the Corsair and SBD?

Also, in Tillman's book on SBDs, pg 180, he states that Corsairs replaced SBDs as the fleet dive bombers.

I did not know that but do we know that the replacement was just due to dive bombing ability? Did the ability to field a good fighter with some dive bomber ability play a role in the decision? The SBD was getting pretty long in the tooth and was limited in the roles in which it could be employed.

Tillman, in his book on the Dauntless, claims that the Dauntless had a "plus" score against enemy aircraft. Is that true? Sounds a bit hard to swallow. If it is not true, I wonder what other claims are not trustworthy.

As I already indicated, the "Thunderbolt accelerated very quickly in a dive and had a higher dive speed than the Corsair. This valuable air combat characteristic would probably be less than ideal for 60 degree bombing angles."

Do you know if the Hellcat was used in dive bombing operations?