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

DAVIDICUS said:

RG_Lunatic:

Are you saying that the Spitfire XIV, Tempest, P-51B, and P-38 could exceed the P-47 in dive speed? I don't think so but at present can offer nothing more in support than what appears below.

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The P-38 critical mach number was lower than that of the P-47, to it's max dive speed would be even lower.

It is important to understand that initial dive acceleration is a huge part of the "dive" performance. This is where the P-47 (and almost all US planes by virtue of their weight) excelled. At the start of the dive a P-47 could quickly pull thousands of feet away of a pursuer. After that, planes with higher critical mach figures would start to slowly catch up.

Also, critical mach figures usually indicate where the plane stops being responsive to controls, and often reflect wing and tail surface mach levels. At this point portions of the airflow over the plane such as the cowl and canopy might already be exceeding mach airflow, causing undesirable flying characteristics. The pursued plane would be less concerned with this than the pursuer, as he does not need to shoot.

Another important issue is terminal dive speed. Both the P-38 and the P-47 (and espeically the Me262) had serious terminal dive speed issues (where a dive could not be recovered and meant an inevitable crash), which were eventually "solved" through the use of dive recovery flaps. Dive recovery flaps had to be deployed at the beginning of a dive, once high speed was attained the hydrolics could not deploy them. These flaps had to reduce the critical mach figure for the planes and also acted as air brakes slowing dive acceleration.

Anyway, both the P-47 and the F4U were large planes with about the same relative power, so both would have had similar initial dive acceleration. The P-47N had a psuedo-laminar flow wing, so perhaps it's critical mach was equal to or higher than that of the F4U-4. Also, the F4U-4 had to be very careful above about 535 mph IAS or the fabric on the wings could be ripped off.

Attached is an interesting document concerning the behaivor of the Spitfire IX at high fractions of mach.

The 700 mph figure quoted is rubbish. Down low the air is just too thick for such speeds from a P-47 (and have the pilot survive), up high that exceeds mach 1. I suspect either the pilot was exagerating or the airspeed indicator was inaccurate at such high speeds (very likely). The maxium reading on the air speed indicator of the P-47 is 700 mph. Any dive steep enough to exceed much over 550 mph in a P-47 was probably terminal. A P-47 at 250 mph at 25,000 feet could not execute a normal power split-S without eating dirt!

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Lunatic

cheddar cheese said:

The Jug certainly was tough, someone posted on here a while back that they had read of a P-47 literally flying through trees (on purpose!) and surviving

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The USAAF and USN conducted post war tests and determined the F4U was the tougher plane. Its wing spar is much stronger (to support carrier operations) and the P-47's turbo-supercharger and fuel tank layout made it more vulnerable to enemy fire.

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Lunatic

altough that's not to say that the P-47 couldn't take damage...........

an CC can you find this post as there were several mentions of P-47's flying through the trees as in below tree top level but no single engined plane could literally fly into a tree and survive.......

No I cant find it...it was months ago and ive no idea where I read it...

well like i said if i'm thinking of the same one as you they were flying below tree top height, think about it, not even the P-47 or corsair could survive a crash with a tree............

You do know I mean just the foliage, not the trunk...

the lancaster kicks ass said:

altough that's not to say that the P-47 couldn't take damage...........

an CC can you find this post as there were several mentions of P-47's flying through the trees as in below tree top level but no single engined plane could literally fly into a tree and survive.......

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There were many cases of P-47's flying into ground objects and surviving. The most famous is one that flew into a radio tower, tore of several feet of one wing, and still made it home.

Also there are many accounts of P-47's, and espeically Corsairs which clipped the tops of trees with their props and survived.

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Lunatic

RG_Lunatic:

You still haven't convinced me that, as you stated, "The Corsair was able to dive at speeds up to 550 mph IAS, which is faster than the max IAS of the P-47."

You now state, "The P-47N had a psuedo-laminar flow wing, so perhaps it's critical mach was equal to or higher than that of the F4U-4. Also, the F4U-4 had to be very careful above about 535 mph IAS or the fabric on the wings could be ripped off."

So it sounds like the P-47 would have an initial dive acceleration advantage due to weight and a likely terminal advantage due to a higher critical mach as well.

On another note, I don't see why Collins claim of "nearly 700 mph indicated airspeed" couldn't be true. He did not say that he was diving at an actual airspeed of 700 mph. You, of course, know what IAS means and I understand that the IAS device was often inaccurate at high speeds. In addition, I would not be surprised if there was a little exaggeration there. He did, however, clearly say that the P-47 was superior to the P-51 in a dive (and he flew both) and you indicated that the Corsair had a critical mach comparable to the P-51.

This is rather nitpicky, I know. I would agree with you that below 30K, the Corsair would have the edge and that that edge would be progressively greater as altitude decreased. Over 30K altitude though, I think the P-47 would wax the corsair.

DAVIDICUS said:

RG_Lunatic:

You still haven't convinced me that, as you stated, "The Corsair was able to dive at speeds up to 550 mph IAS, which is faster than the max IAS of the P-47."

You now state, "The P-47N had a psuedo-laminar flow wing, so perhaps it's critical mach was equal to or higher than that of the F4U-4. Also, the F4U-4 had to be very careful above about 535 mph IAS or the fabric on the wings could be ripped off."

So it sounds like the P-47 would have an initial dive acceleration advantage due to weight and a likely terminal advantage due to a higher critical mach as well.

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Initial dive acceleration would be pretty close. 535 IAS was about the limit of the P-47 as well. If the F4U's fabric had been tightened before the sortie, it could dive faster - the pilot had to pay attention for signs it was rippling.

DAVIDICUS said:

On another note, I don't see why Collins claim of "nearly 700 mph indicated airspeed" couldn't be true. He did not say that he was diving at an actual airspeed of 700 mph. You, of course, know what IAS means and I understand that the IAS device was often inaccurate at high speeds. In addition, I would not be surprised if there was a little exaggeration there. He did, however, clearly say that the P-47 was superior to the P-51 in a dive (and he flew both) and you indicated that the Corsair had a critical mach comparable to the P-51.

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I agree perhaps Collins' claim of the gauge being pegged could be true - if it was poorly calibrated for high speeds or was defective.

The P-47 would pull away from the P-51 quickly at the start of a dive, but then the P-51 would overtake it. This is a known fact from multiple flight tests. The Corsair would do better at the start of the dive than the P-51 because of its weight.

DAVIDICUS said:

This is rather nitpicky, I know. I would agree with you that below 30K, the Corsair would have the edge and that that edge would be progressively greater as altitude decreased. Over 30K altitude though, I think the P-47 would wax the corsair.

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Well, I agree with that. The Turbo-superhcarger on the N was still working well at 35K, the Corsair's was finished by about 30K.

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Lunatic

DAVIDICUS said:

RG_Lunatic:

My understanding was that the M2 was the standard gun used on U.S. aircraft throughout the war. ...

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Just an additional note. The F8F-1 was armed with 4 x M3 .50 BMG's. This gave it the equivilant firepower of 6 x .50's that were deemed sufficient for air-to-air combat.

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Lunatic

RG_Lunatic said:

Also there are many accounts of P-47's, and espeically Corsairs which clipped the tops of trees with their props and survived.

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There was a bombardier I knew who flew in B-24's in the Pacific. He talked all the time about flying in the trees with the glazed nose of the B-24D being raked through limbs with the props chopping through everything. He said they did it just about all the time.

From the book The Pratt Whitney Aircraft Story:

The P-47 was a rugged airplane, without a doubt. During the Battle of the Bulge in 1944, German Field Marshal von Rundstedt had hidden a munitions dump in the woods of the Ardennes. P-47s were called upon to destroy it, but they couldn't find it because of the thick trees. What did the frustrated pilots do then? They flew through the tops of the trees!

Pratt Whitney's representative in Europe, Martin Graham, was there not long afterwards. "You could see by the shattered trees and the torn branches where the P-47s had gone through. You'd have to see it to believe it. Those crazy kids couldn't see what was hidden from above, so they went right into the forest to find out. They cut a path right through the top of the woods. They said every plane that went in and chewed out the tunnel came out — flying, too."

bloody hell

Yes, that is pretty amazing! It took a serious pair of pods to be the first guy to try that!

I know id read about that somewhere! 8)

Aeronavale F4U low pass.

Now this was a bloody Platinum Match.

Agreed.

How did teh new wing on the N model affect its manuverability?

I found interesting in this topic.

Some Facts about P-47N Thunderbolt and F4U-4 Corsair....

Speed: The P-47N Thunderbolt is 21 mph faster than the F4U-4 Corsair and that also 30 mph faster than P-51D Mustang.
Advantage: P-47N Thunderbolt

Climb:
F4U-4 Corsair Rate of climb = 3870 ft/min
P-47N Thunderbolt Rate of climb = Unsure
Advantage: Unsure

Armament: F4U-4 Corsair has 6 x .50 Cals machine guns while P-47N equip with 8 x .50 Cals, but the F4U-4B, the version fitted with four 20mm cannon in place of the six 12.7mm machine guns, kept the very same features as the basic model. The F4U-4B Corsair did not see action in WWII, but it was used with success in the Korean War (1950-1953) and Soccer War (Known as 1969 Football War) as well.
Advantage: P-47N Thunderbolt

Survivability: There was no other single engine fighter flown during the war that could absorb greater battle damage than the F4U Corsair and still get home. Even the USAAF admitted that the F4U was a more rugged airframe than the tank-like P-47 Thunderbolt. That is a remarkable admission. The big Pratt Whitney radial engine would continue to run and make power despite have one or more cylinders shot off (Both fighter used Pratt Whitney).
Advantage: Tie

If anyone disagree about my facts between P-47N Thunderbolt and F4U-4 Corsair, please discuss it here because some of them might be false since I have been looking them up quite for long time.