# Was the F4U Seriously Considered for the European Theatre ?



## timmy (Jun 29, 2012)

Just been reading an article by Chuck Hawks which states



> At one point in 1943, when the Luftwaffe was able to maintain air superiority against the American P-38's and P-47's over France and Germany and shoot down an unacceptable number of American daylight bombers, *the very high performance of the F4U made the US War Department consider using it as a land based fighter in the European Theatre*. The Army Air Force was not anxious to adopt a Navy fighter and declined the early F4U-1 model of the Corsair on the basis of restricted pilot visibility. Later models, such as the definitive F4U-4, had excellent visibility except for an arc directly aft. The Corsair did not have the extreme range capability of the P-38 and the P-51, but its blend of high speed and maneuverability would have made it difficult for the German FW 190 and Bf 109 pilots to handle.



The Super Warbirds of World War II

Its the the first time I have ever read that the F4U was ever considered for the European Theatre
I guess I understand it, in 1943 the F4U may have been a better bet than the Early versions of the P38/P47 ?
With the much improved P47D and the appearance of the P51D Mustang still some time away I guess the USAF needed options 

Anyway is the article true ? Does anyone else have any more information on this ?


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## renrich (Jun 29, 2012)

Interesting article which I had not heard of. There was another instance when the F4U was considered for the ETO. There was a mission proposed where Marine F4Us were to launch from CVEs in the North Sea to destroy German V1 sites. In effect Geroge Marshall said the use of US Marines in the ETO would be over his dead body.


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## NiceShotAustin (Jun 29, 2012)

timmy said:


> Just been reading an article by Chuck Hawks which states
> 
> 
> 
> ...


Nice article. Don't see why it couldn't be true. The reason why the F4U wasnt used in the ETO is also completely completely possible lol


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## vikingBerserker (Jun 29, 2012)

I think the problem with shifting them to the ETO is your are removing them from the PTO. Not sure if that would have been a good idea or not.


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## muscogeemike (Jun 29, 2012)

The RN used F6F’s in the ETO and they also pioneered the use of the F4U on carriers - did they ever use the Corsair in the ETO?

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## vikingBerserker (Jun 29, 2012)

You know, I totally forgot about that. They were used as cover for attacks on the Tirpitz.


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## davebender (Jun 29, 2012)

Shift an equal number of P-38s to the Pacific which Marine pilots would operate from airfields on land ILO the F4U.


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## renrich (Jul 1, 2012)

It is a myth that the RN pioneered the use of Corsairs on carriers. The USN had a squadron ready to deploy to the PTO with the Corsair before the RN even got any Corsairs. Look it up in Dean, "America's Hundred Thousand." The Corsair did serve as the high escort on some of the raids on Tirpitz but no combat resulted.

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## vikingBerserker (Jul 1, 2012)

renrich said:


> It is a myth that the RN pioneered the use of Corsairs on carriers. The USN had a squadron ready to deploy to the PTO with the Corsair before the RN even got any Corsairs. Look it up in Dean, "America's Hundred Thousand."



Another myth down in flames, thanks for the education!


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## razor1uk (Jul 1, 2012)

I think he ment Renrich, 'perfected' or 'assisted' their usage upon carriers - with the curving landing approach method Fleet Airm Arm guys came up with, to make the pilot less blind to the deck and LSO instruction; resulting in greater landing confidence and possibley less landing related crashes/damagings, but that could be rumour too.


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## oldcrowcv63 (Jul 1, 2012)

Tom Blackburn successfully carrier qualified his entire squadron in March 1943 on the CVE Charger! There were many problems encountered but in his memoir "The Jolly Rogers", he claims they were all surmounted and the squadron was ready to deploy on the Bunker Hill (CV-17) by mid-summer when it was pulled in favor of the F6F. BH was the 4th Essex class commissioned and so is a contender for one of the earliest occasions of USN experience with the carrier suitability of the F4U, although, according to Eric Brown, earliest testing was accomplished 9/25/42 when the troubles that plagued its early shipboard service initially appeared. The same source indicates that first RN FAA introduction of the F4U occurred June 1943 so the time table appears to support Renrich's statement.


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## renrich (Jul 1, 2012)

I have posted in detail on this issue before and it is a myth. There is a video online which is a training film for Corsair drivers which shows a field carrier landing with the so called curved final approach. The insignia on the Corsair and the canopy proves that the F4U1 in the film is an early F4U1 before the RN got any Corsairs. The RN pioneered a lot of innovations in carrier operations and they don't need a myth to add to their laurels. 

June 1, 1943 RN Squadron no. 1830 gets first Corsairs at Quonset Pt RI.
July 1, 1943, VF17 goes aboard Bunker Hill
September 28, 1943 Bunker Hill leaves for the Pacific wth VF17 aboard w/Corsairs
November 11, 1943 VF17 lands, is refueled and rearmed on carriers and takes off without problems durint the Battle of Solomon Sea.
December, 1943 Seven Fleet Air Arm squadrons are training on Corsairs I and II.


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## timmy (Jul 3, 2012)

vikingBerserker said:


> *I think the problem with shifting them to the ETO is your are removing them from the PTO*. Not sure if that would have been a good idea or not.



I guess its hard too just ramp up production on extra F4U's

They moved the P-38 to the PTO. Could they have moved the P-47C to the PTO/ Marines as well. Thus freeing up the F4U for the ETO ? 
Would that had been an option if the more competitive P-47D/P51D production was delayed. Which begs the question, would the Marines
P-47C (early models) match the A6M Zeke ?


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## Timppa (Jul 3, 2012)

renrich said:


> It is a myth that the RN pioneered the use of Corsairs on carriers. The USN had a squadron ready to deploy to the PTO with the Corsair before the RN even got any Corsairs. Look it up in Dean, "America's Hundred Thousand." The Corsair did serve as the high escort on some of the raids on Tirpitz but no combat resulted.



I interpret "pioneering the use" as using the plane in combat from carriers. That is what the plane was designed for, right ?
First Fleet Air Arm combat from a carrier:
FAA Corsairs performed their first combat action on 3 April 1944, with Number 1834 Squadron flying from the HMS VICTORIOUS to help provide cover for a strike on the German battleship TIRPITZ.

First US Navy combat operation from a carrier:
Jan 2, 1945, VMF-124’s first carrier born combat mission, escorting TBM’s of Torpedo 4 on an attack on Kagi airfield, Formosa.


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## davparlr (Jul 3, 2012)

Highly unlikely. No operational F4U would outperform its P-47 contemporary in airspeed and climb above 20k ft., except the F4U-4 over the P-47M at 20k, but not above, and this is where the Army wanted control.


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## renrich (Jul 3, 2012)

VF17 conducted combat operations in Corsairs from a US carrier on November 11, 1943.
January 9, 1944, VF(N)-101 ( F4U2s) began to conduct combat operations from Enterprise. AT NIGHT!
Don't those operations count as combat from a carrier? VF17 as well as VF(N)-101 did not learn to operate their Corsairs from carriers from the RN.


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## drgondog (Jul 4, 2012)

Just been reading an article by Chuck Hawks which states

At one point in 1943, when the Luftwaffe was able to maintain air superiority against the American P-38's and P-47's over France and Germany and shoot down an unacceptable number of American daylight bombers, the very high performance of the F4U made the US War Department consider using it as a land based fighter in the European Theatre. The Army Air Force was not anxious to adopt a Navy fighter and declined the early F4U-1 model of the Corsair on the basis of restricted pilot visibility. Later models, such as the definitive F4U-4, had excellent visibility except for an arc directly aft. The Corsair did not have the extreme range capability of the P-38 and the P-51, but its blend of high speed and maneuverability would have made it difficult for the German FW 190 and Bf 109 pilots to handle. 

Reluctantly I fumble around and throw the BS Flag. If Chuck Hawks had not mentioned P-38s and thereby timestamped the Battle of Germany in very LATE 1943 this article may have had a foundation of reality. The first 20 P-51B-1's had been accepted by USAAF in early June 1943 - four months before the first 55th FG first operational sortie in ETO. The were FAR more P-51Bs available in the production lines than would ever be available to the USAAF in March 1944 than F4u-1's if All the USMC dedicated F4U's had been stripped from USN and re-directed to USAAF. 

This epiphony, if including P-38s in ETO, would have occurred in Dec/Jan 1944 when a FLOOD of P-51bs were rolling off the NAA facities in Inglewood and Dallas.

Chancw Vought had zero 'chance' to replace P-51B production in Q1 1944. What coudda happened - Did happen and the P-51s arrived in ETO en masse in march 1944


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## wuzak (Jul 4, 2012)

Did an F4U-1 have any performance advantage over the P-47 in mid/late 1943?


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## wuzak (Jul 4, 2012)

drgondog said:


> The Corsair did not have the extreme range capability of the P-38 and the P-51, but its blend of high speed and maneuverability would have made it difficult for the German FW 190 and Bf 109 pilots to handle.



That is the crux of the matter. Without the range to stay with the bombers, or in their vacinity, for the entire mission the fighters would not need to be engaged by the Luftwaffe as often.


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## drgondog (Jul 5, 2012)

wuzak said:


> That is the crux of the matter. Without the range to stay with the bombers, or in their vacinity, for the entire mission the fighters would not need to be engaged by the Luftwaffe as often.



Wuzak - Chuck Hawks stated this "The Corsair did not have the extreme range capability of the P-38 and the P-51, but its blend of high speed and maneuverability would have made it difficult for the German FW 190 and Bf 109 pilots to handle."

In 1943 The F4U-1 range was far superior to the P-47, was as good or better than the Allison powered P-51 w/internal tank, about the same as the P-51B-1, -5 without the internal fuselage tank and the same as the P-38 with external tanks.

For deep penetrations even the P-51B had to fly to an RV point short of, but reasonably close to the target - no Allied Fighter could pick up a box of B-24s at the Holland/German border and 'Ess' all the way to Posnan for example. That example would call for an R/V near or past Berlin.

During Big Week and through April when the Mustang coverage was ~ 2 FG's per Bomb Division, the relays were (short) P-47s, (intermediate) P-38's and (long) P-51s with internal 85 gallon tanks. The F4U-1 could have perfromed the intermediate escort (up to Berlin) in 1943... and had the ability to carry 361 to 305 gallons of internal fuel versus P-47C (and D) until the P-47D-25 which had 370 but did not enter ops until summer 1944.

This has been hashed to death but the F4U-1 and 1A were far superior range wise until the P-47D-25 entered operations a year after them. The P-47 equivalents always had better performance greater at altitudes >25,000 feet but the Corsair IMO would have been a more formidable opponent against the Fw 190 through that altitude and equivalent to P-51 against the Me 109


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## Timppa (Jul 5, 2012)

renrich said:


> VF19 conducted combat operations in Corsairs from a US carrier on November 11, 1943.
> January 9, 1944, VF(N)-101 ( F4U2s) began to conduct combat operations from Enterprise. AT NIGHT!
> Don't those operations count as combat from a carrier? VF17 as well as VF(N)-101 did not learn to operate their Corsairs from carriers from the RN.



AFAIK (correct if I am wrong), VF-19 refuelled from a carrier, operating from a land base.
If one night fighter unit operated from a carrier before the RN, that is fine.
But if we are not talking about "Guinness World Records " -firsts, don't you agree, that the RN was the first user of the F4U in large scale from carriers. ?

BTW, British made the three crucial inventions, that made the jet carrier aviation possible.


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## renrich (Jul 5, 2012)

The "myth" which is in question is that the RN "taught" the US how to operate Corsairs from carriers. It is not who operated the most Corsairs from carriers first. The USN knew that Corsairs could be operated from carriers and how to do it before the RN even got any Corsairs on carriers and the record amply supports that. The reason that the USN did not use Corsairs on carriers in great numbers until late in the war were twofold. Firstly Hellcat spares and supplies were already in the pipeline when VF17 became ready to deploy in Corsairs. Secondly the USN felt that the Hellcat at that time was safer to operate, especially with low time pilots, from carriers and the Hellcat had sufficient performance to get the job done. The decision then was made to deploy the Corsair in Marine and Navy land based units. Perhaps that was the correct decision at that time. Perhaps not. The Navy made numerous mistakes during WW2, among them being the decision to allow the British to dictate the six gun armament with less ammo per gun of the F4F4 which was later reversed. Perhaps the Corsair decision was another one. However, Grumman could build lots of Hellcats quickly and Vought could build quite a few Corsairs not quite as quickly and all were needed.

VF17, not 19, was landbased. They reinstalled tail hooks. Their pilots had not made any carrier landings in months. They flew out to the task force. Acted as the CAP, shot down 18.5 EA, lost two Corsairs, landed, all safely. Refueled, rearmed, launched and flew home. Seems to me that shows, in spades, that the navy could operate Corsairs in combat from carriers. The Corsairs in the Tirpitz raids had no EA contact. Thus no combat.

Operating night fighter missions in combat by Corsairs from one of the smaller fleet carrier decks in the PTO also seems to me to show the Corsair was ready for carrier duty. I sometimes wonder if what the Navy was doing on the front lines was kept secret from the bureaucrats back in the US. Those bureaucrats often made decisions which seemed to make little sense to the people actually engaged with the enemy.

In an earlier post, I mentioned that the RN pioneered a number of innovations in carrier ops and needed no "Myths" to prove their worth. Angled flight decks. steam catapults, mirror landing system to mention some.


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## davparlr (Jul 5, 2012)

wuzak said:


> Did an F4U-1 have any performance advantage over the P-47 in mid/late 1943?



Except for range, the F4U-1, and the non-water F4U-1A, did not have an apparent advantage over the P-47B/C nor necessarily the German aircraft of 1943. Water injection for the F4U, which improved performance considerably, was not provided for regular operations until well into 1944. A look at the performance levels for speed and climb of the F4U-1, P-47B, Fw 190A-5, and Bf 109G at various altitudes reveals some interesting information.

5k ft
*F4U* 348 mph, 2500 ft./min 
*P-47* 352, 2545
*Fw 190* 367, 3850
*Bf 109* 344, 4234
It is apparent that neither aircraft offers the pilot a lot to work with when fighting the Germans

10k
*F4U* 359, 2440
*P-47* 369, 2465
*Fw 190* 382, 3000
*Bf 109* 362, 3060
Performance is getting closer

15k
*F4U* 378, 2410
*P-47* 386, 2330
*Fw 190* 410, 2400
*Bf 109* 368, 3420

20k
*F4U * 383, 1910
*P-47* 402, 2080
*Fw190* 420, 2400
*Bf 109* 399, 3094
The turbo is starting to show results. Fw 190 is still impressive.

25k
*F4U* 388, 1420
*P-47* 420, 1800
*Fw 190* 416, 1890
*Bf 109* 397, 2244
P-47 is showing its muscles

30k
*F4U* 363, 940
*P-47* 426, 1400
*Fw 190* 379, 1122
*Bf 109* 400, 1625
F4U and fw 190 have checked out at this altitude.

Some apparent conclusions:
While it had range for escort, the F4U-1 without water would have struggled against the German aircraft listed at all altitudes. Its performance was closer to the Fw 190A-3. The water injected, but shorter ranged, F4U-1D, which didn’t appear until 1944, was more equivalent to the A-5.

Up to 15k ft., the F4U-1 and the P-47B were effectively equal in speed and climb. Above 15k ft., the P-47s flat-rated engine was starting to pull away. The F4U should out accelerate the P-47, roll rates seems similar, initial dive benefits the F4U while the P-47 has a higher dive speed. Profile drag coefficient benefits the P-47. All in all, below 20k. ft., Not much to choose from. This data is from Dean’s “America’s Hundred Thousand”.

Below 20k ft., the P-47 was at a definite disadvantage against the German planes although it could typically outrun the Bf 109. It needed to stay high, dive on the enemy and climb back up and do it all again. Combat energy of the P-47 should have been superior due to high altitude and high airspeed unless wasted on dogfighting.

The P-47 definitely held the high ground above 25k ft. If you wanted to protect bombers at 20 and 25k, you definitely wanted the P-47. Now, if you could only get the range up. Of course there are those rumors about a new P-51 with that Merlin engine.

The F4U is a suburb aircraft and consistently showed it growth potential and to perform as it did as a carrier aircraft is admirable. The F4U-1 was not designed for this environment and while it would actually have worked in the long range high altitude escort mission, it was not optimized for it and the pilots would have suffered.


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## renrich (Jul 5, 2012)

Dav, I think the Vmax figures for the P47 @ 5000 feet might be a little high. Should be more like 325-335 in military power but that is probably immaterial from a tactical POV. The F4U1D had the wing tanks deleted but could just have well have had them included. Someone else brought this up in another thread which I thought was a good idea. Take the F4U1A, delete the two outboard 50s and increase the size of the wing tanks so that the weight lost with the guns and ammo is gained back by the tanks and fuel. Then you have a fighter with even more than 361 gallons of internal fuel. Easily done and a good bit more range. Another minor point which is hard to prove but I doubt that the P47 ever had as good a roll rate as the F4U. To me, if the F4U1A had been available in numbers it would have made a lot of sense to use it as an escort fighter because of range until the P51B came along. The P47 would have definitely out performed it above 25000 feet but it still could have been effective. The FWs were not any great shakes above 20000 feet.


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## glennasher (Jul 6, 2012)

Chuck Hawks thinks he knows stuff, I've read bunches of his firearms conclusions, enough to conclude he is often mistaken.................


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## davparlr (Jul 6, 2012)

renrich said:


> Dav, I think the Vmax figures for the P47 @ 5000 feet might be a little high. Should be more like 325-335 in military power but that is probably immaterial from a tactical POV.


I have many holes in my wall for butting it after trying to get stable data. Going back over my data sources on this is typically confusing. There are a couple of test reports that reflect the 350+ number and AHT chart also reflect this, my Wagner’s “American Combat Planes” calls out 340 and some P-47D tests at 2000 hp reflect your number. There are several P-47 tests on propellers which I think are worthless.



> The F4U1D had the wing tanks deleted but could just have well have had them included. Someone else brought this up in another thread which I thought was a good idea. Take the F4U1A, delete the two outboard 50s and increase the size of the wing tanks so that the weight lost with the guns and ammo is gained back by the tanks and fuel. Then you have a fighter with even more than 361 gallons of internal fuel. Easily done and a good bit more range.


I did an earlier quick study on comparison of escort potential for various aircraft including the F4U-1. The result was that the F4U-1 fuel remaining after six hundred mile ingress provided a very similar Normal Rated Power (NRP) operating time over the target as the P-51B. Extra fuel would be nice but I am not sure a necessity.


F4U-1
Internal Fuel, 351 gal
External Fuel, 175 gal
Transit Fuel, 600 miles, 186 gal
Return to Base, 600 miles, 186 gal
Fuel available at combat start, 340 gal (Note: internal fuel was required to be used for ingress after drop tank was empty.)
Fuel available for combat, 154 gal. 
*Combat time at NRP, 1 hour, 6 min.*

P-51B
Internal Fuel 269 gal
External Fuel 216 gal
Transit Fuel, 600 miles 108 gal 
Return to Base, 600 miles 108 gal
Fuel available at combat start 229 gal. Note: 85 gal fuselage tank used down to 65 gal for combat stability.
Fuel available for combat 121 gal 
*Combat time at NRP, 1 hr 14 min.*

This was kind of a thumbnail study but should reflect reasonable comparisons unless there is an error.



> Another minor point which is hard to prove but I doubt that the P47 ever had as good a roll rate as the F4U.


I was just looking at the chart in AHT





> The FWs were not any great shakes above 20000 feet.



Some of the Fw 190A-5 performance capabilities were quite impressive but I do not know the time frame, maybe after 1943.


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## timmy (Jul 7, 2012)

renrich said:


> Dav, I think the Vmax figures for the P47 @ 5000 feet might be a little high. Should be more like 325-335 in military power but that is probably immaterial from a tactical POV. The F4U1D had the wing tanks deleted but could just have well have had them included. Someone else brought this up in another thread which I thought was a good idea. Take the F4U1A, delete the two outboard 50s and increase the size of the wing tanks so that the weight lost with the guns and ammo is gained back by the tanks and fuel. Then you have a fighter with even more than 361 gallons of internal fuel. Easily done and a good bit more range. Another minor point which is hard to prove but I doubt that the P47 ever had as good a roll rate as the F4U. To me, if the F4U1A had been available in numbers it would have made a lot of sense to use it as an escort fighter because of range until the P51B came along. *The P47 would have definitely out performed it above 25000 feet* but it still could have been effective. The FWs were not any great shakes above 20000 feet.



I'm just curious, does anyone on this forum have any information on what altitude Escort Fighters mostly saw combat in the ETO? I think I remember reading that B-17s flew around 25 000ft with a full load. The B-24 I think was under that, so am I correct in guessing its around 25 000ft ????

Just another question, what do most people think is the average altitude range in a dogfight. Like say for example the enemy meet at 25000ft,
would an average dogfight normally range from 20 000 to 30 000ft from that point ? All are each individual Dogfights just to viable even to make even a rough estimate on their combats altitudes range ??


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## Shortround6 (Jul 7, 2012)

Altitude for "Mostly saw combat" and mostly flew at before combat might not be the same thing. Some of the fighters would fly above the bombers to intercept the the Germans before they could dive down on the bombers. Most fighter to fighter combats usually descended in altitude if the fight went on for very long. No fighter of the time could sustain speed while executing maneuvers and the only way to keep speed up was to dive. Combats could end near the height they started or almost at ground level if the pursuit took long enough. Which ever side could start the fight with the higher altitude had an advantage which is why the fighters needed more altitude ability than the bombers.


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## renrich (Jul 7, 2012)

Timmy, great question. I believe that most of us have an exaggerated idea of how high the bombers flew. Having looked at some mission stats it seems that the bombers flew a little higher as the war wore on probably as the flak became thicker. The flak killed more bombers than did fighters. The B24s could not fly as high as the B17s and weather and visibility had a lot to do with the altitude flown. At one point I believe that frostbite was disabling more aircrewmen than enemy action. I doubt that many if any bomber altitudes were at 30K feet. Also, the medium bombers flew at lower altitudes than the heavies. A guess from me would be that the average altitude flown in combat by the heavies would be around 24K feet. Some of the fighter escort would fly above the bombers but if they got too high they risked not being able to see the interceptors.


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## tomo pauk (Jul 7, 2012)

davparlr said:


> > [renrich:]The FWs were not any great shakes above 20000 feet.
> 
> 
> Some of the Fw 190A-5 performance capabilities were quite impressive but I do not know the time frame, maybe after 1943.



There might be 3 'eras', to describe the performance of the Fw-190 with BMW 801D:
-March 1942 to Autumn 1942 - engine ratings are restricted, but the 190 is still perhaps the best performer among fighters
-Autumn 1942 to beginning of 1944 - restriction is lifted, the 190 is maybe the best all-around fighter, lacking only the combat range. Those are the A-4, A-5, A-6, A-7s.
-Spring 1944 - the heavy A-8 is int the units, the performance suffers, especially above 20000 ft, playing into (not only) USAAF hands.

MW-50 sets for the 190s are helpful only under 20 - 22 kft.

David's figures list the performance of the A-5 (non-restricted, really a great fighter.


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## timmy (Jul 7, 2012)

Shortround6 said:


> Altitude for "Mostly saw combat" and mostly flew at before combat might not be the same thing. Some of the fighters would fly above the bombers to intercept the the Germans before they could dive down on the bombers. Most fighter to fighter combats usually descended in altitude if the fight went on for very long. No fighter of the time could sustain speed while executing maneuvers and the only way to keep speed up was to dive. Combats could end near the height they started or almost at ground level if the pursuit took long enough. Which ever side could start the fight with the higher altitude had an advantage which is why the fighters needed more altitude ability than the bombers.


 


renrich said:


> Timmy, great question. I believe that most of us have an exaggerated idea of how high the bombers flew. Having looked at some mission stats it seems that the bombers flew a little higher as the war wore on probably as the flak became thicker. The flak killed more bombers than did fighters. The B24s could not fly as high as the B17s and weather and visibility had a lot to do with the altitude flown. At one point I believe that frostbite was disabling more aircrewmen than enemy action. I doubt that many if any bomber altitudes were at 30K feet. Also, the medium bombers flew at lower altitudes than the heavies. A guess from me would be that the average altitude flown in combat by the heavies would be around 24K feet. Some of the fighter escort would fly above the bombers but if they got too high they risked not being able to see the interceptors.



Good information, thanks for the replies guys


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## renrich (Jul 8, 2012)

The best reference I have on the FW190 is a lengthy article in "The Great Book of WW2 Airplanes." It is quite detailed and because of the German tendency to get over complicated the reader can get confused about all the different Mks. and models. To me, what is quite interesting is that the FW190 design began in 1937 and the gestation of the airplane was somewhat similar to that of the F4U but always about a year ahead. The Corsair design was begun in 1938. The design of the two AC was determined based on two radial powerplants by BMW and P&W which were under development at the same time the AC were being developed. Engine problems were many for both AC with the loss of quite a few early models because of engine failure. The FW also had overheating problems in the early models. One of the early prototype FWs attained a top speed of 369 mph in level flight in 1939. The Corsair protoype got 405 mph in 1940. As the AC designs evolved the performance numbers for the two were similar except that the FW always climbed better and the F4U always had more range. The FW became more heavily armed and the Corsair, of course, had to be a ship board AC. The radial engined FW lost much of it's performance above 15000-20000 feet and the engine was changed out to a liquid cooled in order to cope with the high flying heavy bombers. That was the D models.

To me, having had a lot of experience with a lot of cars, American, German and Japanese. The motto of American car builders seems to be "keep it simple stupid" while the German's is "keep it complicated smarty" and that seems to have been the tendency of the WW2 AC designers also. (editorial on my part and just an opinion)


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## drgondog (Jul 8, 2012)

renrich said:


> Timmy, great question. I believe that most of us have an exaggerated idea of how high the bombers flew. Having looked at some mission stats it seems that the bombers flew a little higher as the war wore on probably as the flak became thicker. The flak killed more bombers than did fighters. The B24s could not fly as high as the B17s and weather and visibility had a lot to do with the altitude flown. At one point I believe that frostbite was disabling more aircrewmen than enemy action. I doubt that many if any bomber altitudes were at 30K feet. Also, the medium bombers flew at lower altitudes than the heavies. A guess from me would be that the average altitude flown in combat by the heavies would be around 24K feet. Some of the fighter escort would fly above the bombers but if they got too high they risked not being able to see the interceptors.



Ren- In the ETO, particularly as weather worsened and cloud cover frequently 10/10 the bombers flew significantly lower in 1945. I just looked through R/V altitudes and Mission summaries for Jan-March 1945. There were many B-24 strikes at ~ 18.000-20K feet as well as B-17 strikes in the 22-23,000 foot range.

I can't find any particular written observations regarding the "why' - just the data. Also notably the German flak gunners started targeting H2X radars for fusing and tracking info in the summer of 1944, which required countermeasures to reduce effectiveness. The 10/10 cover affected both bombing accuracy and flak accuracy, despite lower altitude runs.


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## JoeB (Jul 8, 2012)

davparlr said:


> I did an earlier quick study on comparison of escort potential for various aircraft including the F4U-1. The result was that the F4U-1 fuel remaining after six hundred mile ingress provided a very similar Normal Rated Power (NRP) operating time over the target as the P-51B. Extra fuel would be nice but I am not sure a necessity.
> 
> 
> F4U-1
> ...


The important assumption you make about fuel quantities is that the F4U-1 will enter combat with fuel in the unprotected internal wing tanks. The standard USN assumption was that it would not. Therefore in the 'A/c Characteristics and Performance' sheet for F4U-1 dated March 1 1944, the official radius is the same whether the internal wing tanks are used or not, 340 statute miles (they list capacities of 237 main internal protected tank, 175 gal drop, and optional condition adding 2*62 unprotected internal, total 536, a little different from what you said but same general idea I assume). In the unprotected tanks case, the a/c was assumed to drop 166 gal in the drop tank if entering combat immediately 340 miles out, or else would have a 186 min CAP endurance. Not using the wing tanks, it would drop 48 gals in the drop tank or be able to patrol for 54 minutes at the 340 mile radius.

The 340 would still not be apples and apples to your estimate because it includes conservative deductions for warm up, take off, marhalling and climb which you haven't included, but in any cases those assumptions could be relaxed for a land based a/c. But, sticking to the assumption of no unprotected internal fuel in combat, the F4U's radius was still not 600 statute miles, and no actual operation I know of contradicts this. Whereas, the P-51's practical combat radius really was over 600 miles as shown by actual operations by P-51D/K's in the Pacific. OTOH the F4U could have been further modified to achived greater range, as was the P-51 (as in 85 gal tank, not originally installed in very early series B's).

Joe


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## renrich (Jul 8, 2012)

Another coincidence about the development of the FW190 and F4U was accidents with the prototype. The FW had several prototypes and one had a bad accident. The AC was rebuilt using the planned for larger wing and tail surfaces. The Corsair prototype had a bad accident and was rebuilt like the original. An interesting what if to me is what if the original design of the Corsair was taken and a model built strictly for land based use. With no wing fold, no tail hook and with the structure stressed for landing on air fields instead of carrier decks and with no salt water protection, there must have been some significant weight loss. In addition a different air foil may have meant less drag but longer takeoff and landing distances along with a higher stall speed but better Vmax, climb and acceleration. Also Dean in AHT speculates that the right wing spoiler may have adversely effected the Corsair's turn rate. That spoiler would have been probably left off the land version. I am no engineer but if a thousand pounds were saved along with a less draggy air foil a very high performance AC could have resulted.


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## Shortround6 (Jul 8, 2012)

renrich said:


> An interesting what if to me is what if the original design of the Corsair was taken and a model built strictly for land based use. With no wing fold, no tail hook and with the structure stressed for landing on air fields instead of carrier decks and with no salt water protection, there must have been some significant weight loss.



Some of the Goodyear production did not have folding wings or or tail hooks. So far little or no difference in performance has come to light. It may be there, just the documents haven't been dug out yet? 




renrich said:


> In addition a different air foil may have meant less drag but longer takeoff and landing distances along with a higher stall speed but better Vmax, climb and acceleration.



Now you have a new wing that needs flight testing and may or may not be able to be built using existing tooling, jigs, fixtures. Some will have to change but how much?




renrich said:


> I am no engineer but if a thousand pounds were saved along with a less draggy air foil a very high performance AC could have resulted.



You are quite likely correct, the question is _WHEN_ such an aircraft could have shown up? How many weeks to design the new wing, how many weeks to build the prototype, how many weeks to test fly it, how many weeks to design and build the new jigs and fixtures. The First F4U-1D isn't accepted by the Navy until April 22 1944.


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## renrich (Jul 8, 2012)

I think what I am speculating about is, if in 1940 when the XF4U flew at 400 plus mph, a different manufacturer had taken the blueprints and tweaked the design . I don't think the FGs with no tail hook and wing fold gained a lot of performance but it must have meant a few hundred ponds less. A few hundred pounds on an F4F or F2A was a big deal but not on a Corsair. As I say, I am no engineer except for two years in college and then realised I was not cut out for that and became a geology major but it seems as if an air plane stressed for deck landings would have to weigh somewhat more than the same AC stressed only for landing on air fields. Eastern built a lot of FMs and TBMs after Grumman designed them and several other manufacturers built AC designed by others. Could be a pie in the sky.


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## davparlr (Jul 8, 2012)

Okay, here is an estimate for a F4U-1 built to AAF requirements using the F-86F/FJ-2 similarities. Effectively, the FJ-2 was navalized F-86F with four cannon instead of six guns, which were roughly the same weight total. The empty weight of an F-86F is 10,815 lbs and the FJ-2 is 11,802 lbs or 92% less. So, a one-to-one comparison to the F4U-1, at an empty weight of 8982 an AAF designed F4U would be 8231 or 750 lbs lighter. However, the FJ-2 lands much faster than the F4U-1 and therefore probably has more structure and gear modifications than the F4U-1. So let's guesstimate a 500 lb savings. This would have improved climb by 2-300 ft/min. This weight is close to the Fw-190A empty weight, and reducing the wing area 30% to roughly the area of the Fw, there is reason to believe its performance would be equivalent to the A-5. However, where would you put the fuel?


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## davparlr (Jul 8, 2012)

JoeB said:


> The important assumption you make about fuel quantities is that the F4U-1 will enter combat with fuel in the unprotected internal wing tanks. The standard USN assumption was that it would not. Therefore in the 'A/c Characteristics and Performance' sheet for F4U-1 dated March 1 1944, the official radius is the same whether the internal wing tanks are used or not, 340 statute miles (they list capacities of 237 main internal protected tank, 175 gal drop, and optional condition adding 2*62 unprotected internal, total 536, a little different from what you said but same general idea I assume).


"Americas Hundred Thousand" list wing tanks holding 57 gallons. I would guess the performance sheet is correct if it is from the Navy.



> In the unprotected tanks case,



Originally the wing tanks were protected by a CO2 system. I am not sure of the effectiveness of this system but my assumption was that it was. There was apparently room for wing tanks that may possibly have been protected, with less fuel.



> the a/c was assumed to drop 166 gal in the drop tank if entering combat immediately 340 miles out, or else would have a 186 min CAP endurance. Not using the wing tanks, it would drop 48 gals in the drop tank or be able to patrol for 54 minutes at the 340 mile radius.



My assumption was that the drop tanks would not be released until contact with the enemy air, in this case over the target area. As long as the assumption is applied across the board, data is usable. In the F4U case I did assume wing tank were combat usable, or could be made that way. Contact with enemy air anywhere prior to target area obviously would affect performance, but again, if applied equally to subject candidates, impact would also be similar.



> The 340 would still not be apples and apples to your estimate because it includes conservative deductions for warm up, take off, marhalling and climb which you haven't included, but in any cases those assumptions could be relaxed for a land based a/c.


My assumption was that each candidate would be required to obtain similar departure and recovery requirements thus cancelling the affect. I realize that F4U would probably utilize more fuel in this effort than say the P-51, but I was too lazy to calculate it and suspect the difference is rather a small % of overall effort. I could be off a bit.



> But, sticking to the assumption of no unprotected internal fuel in combat


Not necessarily reasonable since this would be an AAF aircraft modified to support long range escort duty.

The purpose of this quick study was not to generate a detailed fuel usage report mainly due to my concern about the lack of available data, but to just provide a thumb nail comparison for a clearer picture of the candidates escort capabilities.


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## drgondog (Jul 9, 2012)

davparlr said:


> Okay, here is an estimate for a F4U-1 built to AAF requirements using the F-86F/FJ-2 similarities. Effectively, the FJ-2 was navalized F-86F with four cannon instead of six guns, which were roughly the same weight total. The empty weight of an F-86F is 10,815 lbs and the FJ-2 is 11,802 lbs or 92% less. So, a one-to-one comparison to the F4U-1, at an empty weight of 8982 an AAF designed F4U would be 8231 or 750 lbs lighter. However, the FJ-2 lands much faster than the F4U-1 and therefore probably has more structure and gear modifications than the F4U-1. So let's guesstimate a 500 lb savings. This would have improved climb by 2-300 ft/min. This weight is close to the Fw-190A empty weight, and reducing the wing area 30% to roughly the area of the Fw, there is reason to believe its performance would be equivalent to the A-5. However, where would you put the fuel?



Dave - I wouldn't count on proportionality comparisons. Speculatively I would think the combination of spar strengthening, arresting gear and wing fold structure delta between FJ-2/F-86 would not be far off in gross delta between F4U Navy and F4U AAF. I would expect 700-900 pound difference with the highest percentage in the arresting gear and wing fold structures - IF the F4U AAF was designed as a land based fighter from the beginning. As a 'retrofit' with new wing/gear only and simply remove arresting hook - your figure seems reasonable.


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## renrich (Jul 10, 2012)

Just stumbled on some data on the Corsair which is highly interesting and may answer some questions which have been raised on numerous occasions in this forum. The data is on the Williams site. This data seems to have just appeared on the site or at least it is the first I have seen of it. It is the reprint of an acceptance test of an F3A in !944 at Patuxent. The F3A is the Brewster version of the F4U1. The question has been posed many times about the alleged legendary roll rate of the Corsair and even in AHT by Dean there is very sketchy data. The Corsair has been said to be a really good roller but little proof has been offered.

In the test the Corsair was able to roll 112 degrees in one second at 300 mph IAS either right or left. That is of course less than 4 seconds for a 360 roll which Dean states is a very good roll rate.. Boone Guyton said in his book that he was able to roll 180 degrees in one second but I suspect that he was at a higher speed than 300 mph IAS. The stick force necessary was pretty low also. Another interesting point too was that on this particular AC the Vmax at critical altitude was faster in normal power than in military power. That was said to be because of prop efficiency at the lower rpms.


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## drgondog (Jul 11, 2012)

Ren - at 112 per second it conceivably rolls 448 degrees for 4 seconds?

As to prop speed. The Mustang experienced the same phoenomena believed to be drag losses due to tip speed at 3000 rpm/29,000 feet...but the 51 used 3000 rpm at both MP and WEP for the 11'-2" blade diameter


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## renrich (Jul 11, 2012)

To follow up a similar acceptance test of the FG1 did not do nearly as well as the F3A1 in the roll test. That, to me, points up that individual AC have different performance characteristics. If as a combat pilot you got one of the good ones you were better off than the guys who got the dogs, unless you were able to get your dog tuned up.


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## NeilStirling (Jul 12, 2012)

Hi Shortround6,

_Some of the Goodyear production did not have folding wings or or tail hooks. So far little or no difference in performance has come to light. It may be there, just the documents haven't been dug out yet? _

http://www.wwiiaircraftperformance.org/f4u/FG-1A_14575.pdf

Thanks to Mike Williams.

Neil


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## davparlr (Jul 12, 2012)

renrich said:


> To follow up a similar acceptance test of the FG1 did not do nearly as well as the F3A1 in the roll test. That, to me, points up that individual AC have different performance characteristics. If as a combat pilot you got one of the good ones you were better off than the guys who got the dogs, unless you were able to get your dog tuned up.


 
I read that too and just laughed since it seems to be typical of performance data on the F4U, in other words all over the place. Very frustrating. However, I have three ideas as to why this is so. One is the same as yours in that manufacturing variables could affect roll rates to this amount, second, the F3A1 seems to be measured over 90 degrees and the FG1 was measured over 360 degrees, perhaps roll rate varied over orientation, and third, which I think is probable is measuring error. I don't know if this was done by instrumentation or manually. If manually, I can certainly see a great variance due to measuring error and if by instrumentation the error probability is also reasonable.


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## renrich (Jul 12, 2012)

I was an engineering student in a co op program in 1955 and worked for 8 weeks at Temco Aircraft in Flight Test Instrumentation. We were running tests on the TT-1 and I was reading and recording the data. Perhaps some engineering student like me was recording the data on the FG1 since the data of the F3A1 seems to agree more with Boone Guyton's.


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## FLYBOYJ (Jul 12, 2012)

renrich said:


> I was an engineering student in a co op program in 1955 and worked for 8 weeks at Temco Aircraft in Flight Test Instrumentation. *We were running tests on the TT-1* and I was reading and recording the data. Perhaps some engineering student like me was recording the data on the FG1 since the data of the F3A1 seems to agree more with Boone Guyton's.



The Pinto?!? LOL! I worked on one recently!


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## renrich (Jul 12, 2012)

Yes, the Pinto. There were not many produced and I had no idea there were any left around. Was it still operational?


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## FLYBOYJ (Jul 12, 2012)

renrich said:


> Yes, the Pinto. There were not many produced and I had no idea there were any left around. Was it still operational?


I don't think the navy used them long but a few wound up in civilian hands. The one I was involved in had a J-85. Neat little bird, real simple to work on.


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## renrich (Jul 12, 2012)

I looked up the TT1 on Wicki and it says the first flight was in 1956. I know I was working at Temco in the fall of 1955 so the AC we were testing must have been the Plebe or Buckaroo. I am almost positive it had a recip engine also. I was not around the AC much if any but was stuck back in a dark room looking at film shot of the instrument panel and recording data and time. At the same time Vought next door was designing the F8U and the secret which leaked out to us was that it had a variable incidence wing. At the NAS next door they were doing a lot of work on F7U Cutlasses. The word I heard was that among other issues the engines would flame out when the guns were fired. Temco was also manufacturing the aft fuselage of the F101. I remember there was a lot of titanium in that aft fuselage. The next 8 week period ( we were in school 8 weeks and worked 8 weeks) I was in illustrations and publications department and then switched majors.


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## Shortround6 (Jul 12, 2012)

FLYBOYJ said:


> I don't think the navy used them long but a few wound up in civilian hands. The one I was involved in had a J-85. Neat little bird, real simple to work on.



Isn't that the _SUPER_ Pinto ?


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## JoeB (Jul 12, 2012)

davparlr said:


> 1. "Americas Hundred Thousand" list wing tanks holding 57 gallons. I would guess the performance sheet is correct if it is from the Navy.
> 
> 2. Originally the wing tanks were protected by a CO2 system. I am not sure of the effectiveness of this system but my assumption was that it was.
> 
> 3. The purpose of this quick study was not to generate a detailed fuel usage report mainly due to my concern about the lack of available data, but to just provide a thumb nail comparison for a clearer picture of the candidates escort capabilities.


I don't see why we wouldn't assume the same for 2 as 1, that the USN sheet is correct. It clearly identifies those tanks on the diagram of fuel tanks as 'unprotected'. As I said, if the USAAF wanted to use the F4U for long range land operations, if could always modify it any number of ways, but as for F4U's as actually equipped the USN assumption was as mentioned, that the wing tanks wouldn't be used to directly supplement the main tank. And to clarify the math of the ACP sheets, under the USN assumptions the 237 gal main tank was enough for combat (8.5 min at combat power, 11.5 at military) and a 60 minute cruising reserve at a radius of 340 miles; that's where 340 comes from and why the number is still 340 whether the wing and drop tanks were used or just the drop tank. Their assumption, not just mine, was that the internal wing and drop tanks couldn't be used for any of the combat, or thus return cruise, requirement.

3. I think with all due respect it may be too quick and simple. Again, if F4U's as actually equipped could easily fly 600 mile radius missions, then they would have flown from Munda directly against Rabaul from summer 1943, which is only around 475 miles one way (the Rabaul based Zero 21 missions in 1942 against G'canal were 650 miles one way; there was never any idea of US fighters of 42-43 flying that mission in the other direction). But they didn't fly against Rabaul until bases on Bouganville were secured around 250 miles from Rabaul. So I think F4U lack of 600 radius is demonstrated in real operations where it would have come in handy if it were actually true. But again Merlin/85gal tank P-51's could operate at 600 miles, again as shown by actual missions.

This suggests to me there's something wrong with your calculations.

Joe


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## renrich (Jul 13, 2012)

Somewhere on the Williams site there is a Navy sheet which shows an F4U with a combat radius from a carrier as 550 miles. I think it was an F4U1D without internal wing tanks but with two 150 gallon drop tanks one of which was protected. The protected drop tank was retained during the whole flight and the combat radius was determined with all the usual data like take off , climb, circle and eventually reserve to find the carrier which probably would not be where it said it would be. That CR would not have much relevance though to 1942-43.


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## FLYBOYJ (Jul 13, 2012)

renrich said:


> Yes, the Pinto. There were not many produced and I had no idea there were any left around. Was it still operational?



Yes, was going through a condition inspection. I believe there's about 3 or 4 of them in private hands.


Shortround6 said:


> Isn't that the _SUPER_ Pinto ?


Yep!


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## Shortround6 (Jul 13, 2012)

renrich said:


> Somewhere on the Williams site there is a Navy sheet which shows an F4U with a combat radius from a carrier as 550 miles. I think it was an F4U1D without internal wing tanks but with two 150 gallon drop tanks one of which was protected. The protected drop tank was retained during the whole flight and the combat radius was determined with all the usual data like take off , climb, circle and eventually reserve to find the carrier which probably would not be where it said it would be. That CR would not have much relevance though to 1942-43.



Navy ranges/radius tend to be longer than Army ranges/radius due to the Navy planes being able to cruise at lower speeds on the return trip.


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## renrich (Jul 13, 2012)

Yes but they have to have more reserve fuel because their air fields can be hard to find.


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## FLYBOYJ (Jul 13, 2012)

JoeB said:


> I think with all due respect it may be too quick and simple. Again, *if F4U's as actually equipped could easily fly 600 mile radius missions, then they would have flown from Munda directly against Rabaul from summer 1943, which is only around 475 miles one way *(the Rabaul based Zero 21 missions in 1942 against G'canal were 650 miles one way; there was never any idea of US fighters of 42-43 flying that mission in the other direction). But they didn't fly against Rabaul until bases on Bouganville were secured around 250 miles from Rabaul. So I think F4U lack of 600 radius is demonstrated in real operations where it would have come in handy if it were actually true. But again Merlin/85gal tank P-51's could operate at 600 miles, again as shown by actual missions.
> 
> This suggests to me there's something wrong with your calculations.
> 
> Joe





renrich said:


> Somewhere on the Williams site there is a Navy sheet which shows an F4U with a combat radius from a carrier as 550 miles. I think it was an F4U1D without internal wing tanks but with two 150 gallon drop tanks one of which was protected. The protected drop tank was retained during the whole flight and the combat radius was determined with all the usual data like take off , climb, circle and eventually reserve to find the carrier which probably would not be where it said it would be. That CR would not have much relevance though to 1942-43.



Also consider how these aircraft were being flown during those operations. Were they operating at cruising speeds the entire flight? Altitude? Were they flown straight and level or flying "zig zags?" Weather conditions? How much reserves were they giving themselves? 30 mins? 60 mins? Just some thoughts...


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## Shortround6 (Jul 13, 2012)

renrich said:


> Yes but they have to have more reserve fuel because their air fields can be hard to find.



True but many of the "bench mark" or theoretical ranges for navy planes are at speeds under 200mph and sometimes altitudes of 5000ft. Now this might or might not be a realistic cruise condition returning from a carrier strike or Island raid over open water with no flak guns and little or no pursuit. Defending enemy planes having to return to the ship or Island for fuel and so are unlikely to pursue far. Army fighters, at least in Europe, would almost be committing suicide to cruise back over France at such a speed and altitude. Aside from the Flak guns, such a speed and altitude gives up too much initiative to defending fighters. Over Germany and France the defending fighters can pursue allied aircraft away from their own base with the knowledge that they can land at another airfield to refuel. Granted the German fighters did not have the range of the Japanese fighters to begin with but after the British losses of 1941/42 the standard survival tactic was to "cruise" as fast as possible over enemy territory, fuel consumption permitting. Planning an operation with a cruise of 200mph in 1943 probably would not have been given the go ahead. 
A Corsair burned roughly twice the fuel per minute as max lean power as it did at it's most economical settings. The reserve for "looking for the carrier" was figured at the economical settings. 

I would want a double check on that dog fighting with a 150 gal tank still attached to the plane. Corsairs were big, tough airplanes but 150 gals of fuel is 900lbs, add the tank and you are darn close to 1000lbs. Add the drag of the tank and it is going to cut into climb and speed a significant amount.


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## timmy (Jul 13, 2012)

renrich said:


> Somewhere on the Williams site there is a Navy sheet which shows an F4U with a combat radius from a carrier as 550 miles. I think it was an F4U1D without internal wing tanks but with two 150 gallon drop tanks one of which was protected. The protected drop tank was retained during the whole flight and the combat radius was determined with all the usual data like take off , climb, circle and eventually reserve to find the carrier which probably would not be where it said it would be. That CR would not have much relevance though to 1942-43.


 
I'm sure I have read some where on this forum that if you had any protrusions like drop tanks behind the propeller line, it produced so much more wind resistance meaning less range. While mounting drop tanks outside the propeller line (P51) produces a lot less wind resistance, better range

Now I understand why Vought mounted the external tanks under the fuselage as it produces less stress on the wings. But if Vought was serious in adding range to the f4u wouldn't it be better mounting those tanks on the outer wings ? An F4U wing would certainly be strong enough

Anyway just wanted to add my thouhts


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## VBF-13 (Jul 14, 2012)

Timmy the F4U gull design was made to order for those tanks right where they're at. Aerodynamically that's a pretty stable position and I'd surmise that's the principal reason they're there. The tanks will interfere with the wash from the prop causing drag but you must also remember they're dropped once that aircraft is in combat. 

BTW, are you the photographer? If so, what air show was that? That's just an awesome shot of that F4U, fully-loaded for business, rockets and all. Very impressive!


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## davparlr (Jul 14, 2012)

JoeB said:


> I don't see why we wouldn't assume the same for 2 as 1, that the USN sheet is correct. It clearly identifies those tanks on the diagram of fuel tanks as 'unprotected'.


Quote from pilots manual.
_“4.i WING TANK VAPOR DILUTION SYSTEM OPERATION. ----Provision is made, on airplanes having outer panel integral wing tanks, for making the atmosphere above the fuel inert, for protection from gunfire during combat, by admitting CO2 to the wing tanks.”_

There is a warning saying use of vapor dilution system while using the fuel from the tank will cause fuel flow interruption. However fuel is still useable. There is no warning regarding use of wing tanks in combat or of emptying wing tanks prior to combat.

I think combat with fuel in the wing tanks was initially anticipated and planned for. The AAF added a destabilizing 85 gallons to the P-51B and I think adding more internal fuel to the F4U would be less problematic. However, the same could be said for the P-47, which the AAF would have more likely chosen. The real problem was that the AAF did not acknowledge a need for a long range fighter until late and by then the P-51 was showing promise. Without using the wing tanks for combat either with CO2 or adding protection, the F4U-1 would not be able to perform deep escort, not even a well as the P-47.



> As I said, if the USAAF wanted to use the F4U for long range land operations, if could always modify it any number of ways, but as for F4U's as actually equipped the USN assumption was as mentioned, that the wing tanks wouldn't be used to directly supplement the main tank.



This was Navy procedures. Would it have been the AAF’s if it was desperate to protect its bombers? 



> And to clarify the math of the ACP sheets, under the USN assumptions the 237 gal main tank was enough for combat (8.5 min at combat power, 11.5 at military) and a 60 minute cruising reserve at a radius of 340 miles; that's where 340 comes from and why the number is still 340 whether the wing and drop tanks were used or just the drop tank. Their assumption, not just mine, was that the internal wing and drop tanks couldn't be used for any of the combat, or thus return cruise, requirement.



Not pertinent. As long as the comparison uses equal criteria, it is appropriate. I simply used fuel available at contact with enemy air, subtracted fuel required to return to overhead base 600 miles away, and calculated the max time at Mil power on remaining fuel. All other variables, such as min. at Combat, min. at Mil, would be proportional to this number when applied equally to each airframe. In addition since assembly and recovery would have to be the same these cancelled out. Some error in incurred because some aircraft will use more fuel than others for this effort.



> 3. I think with all due respect it may be too quick and simple. Again, if F4U's as actually equipped could easily fly 600 mile radius missions, then they would have flown from Munda directly against Rabaul from summer 1943, which is only around 475 miles one way (the Rabaul based Zero 21 missions in 1942 against G'canal were 650 miles one way; there was never any idea of US fighters of 42-43 flying that mission in the other direction). But they didn't fly against Rabaul until bases on Bouganville were secured around 250 miles from Rabaul. So I think F4U lack of 600 radius is demonstrated in real operations where it would have come in handy if it were actually true. But again Merlin/85gal tank P-51's could operate at 600 miles, again as shown by actual missions.



Again, not pertinent. The aircraft could probably have performed the mission but Naval operational procedures apparently, maybe rightly so, felt the mission was not worth the risk. The Japanese would have readily accepted the risk, as they did with the Zero. And, maybe the AAF would have done the same over Germany to save their bombers, and maybe not. 



> This suggests to me there's something wrong with your calculations.



Only because you don’t recognize it is a comparison of equal scenarios and not an individual mission based operational plan. I did make some thumbnail assumptions such as using the P-47 cruise number for F4U numbers because I had good P-47 data and did not have good data for the F4U. The F4U is lighter and would probably have slightly better performance per gallon.


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## RCAFson (Jul 14, 2012)

Shortround6 said:


> True but many of the "bench mark" or theoretical ranges for navy planes are at speeds under 200mph and sometimes altitudes of 5000ft. Now this might or might not be a realistic cruise condition returning from a carrier strike or Island raid over open water with no flak guns and little or no pursuit. Defending enemy planes having to return to the ship or Island for fuel and so are unlikely to pursue far. Army fighters, at least in Europe, would almost be committing suicide to cruise back over France at such a speed and altitude. Aside from the Flak guns, such a speed and altitude gives up too much initiative to defending fighters. Over Germany and France the defending fighters can pursue allied aircraft away from their own base with the knowledge that they can land at another airfield to refuel. Granted the German fighters did not have the range of the Japanese fighters to begin with but after the British losses of 1941/42 the standard survival tactic was to "cruise" as fast as possible over enemy territory, fuel consumption permitting. Planning an operation with a cruise of 200mph in 1943 probably would not have been given the go ahead.
> A Corsair burned roughly twice the fuel per minute as max lean power as it did at it's most economical settings. The reserve for "looking for the carrier" was figured at the economical settings.
> 
> I would want a double check on that dog fighting with a 150 gal tank still attached to the plane. Corsairs were big, tough airplanes but 150 gals of fuel is 900lbs, add the tank and you are darn close to 1000lbs. Add the drag of the tank and it is going to cut into climb and speed a significant amount.



In fact if you look at the consumption curves of the A6M-3 you can see that it achieved its long range by using very low throttle settings (which also implies very low altitude):
http://www.wwiiaircraftperformance.org/japan/Zeke-32-TAIC-102C.pdf

At ~280 mph, range falls to about 260 miles, or probably less than an Me109e at the same speed, but at about 150mph range is nearly 900 miles (all ranges on internal fuel).


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## renrich (Jul 14, 2012)

Timmy raises an interesting point and very good photos. The F14 carried most of (or all) of it's missles, bombs in the tunnel and carrying it there was called conformally. That allegedly meant that there was no drag penalty and the air plane was as fast with the missles as without. I wonder if there was a somewhat similar situation with the Corsair and that the twin external 150 gallon tanks carried in the inverted gull section did not extract as much drag penalty as twin tanks did on an AC with a conventional wing?


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## renrich (Jul 14, 2012)

OK, I went to the Williams site and here is the data observed from the 1-12-06 posting on the F4U1D Perfomance section.
This is fighter load with 2400 rds of ammo and this is the AC with pylons for rockets or bombs. 
The AC has two 150 gallon drop tanks one protected and one not for a fuel load of 534 gallons. The protected tank is retained.
Warm up-20 minutes
Take off -one minute
Rendesvous- at SL-20 minutes
Cruise at 15000 feet set for max range
Combat-20 minutes @ 15000 feet 8.5 minutes WEP, 11.5 minutes Military and descend
Cruise back at 1500 feet at 170 knots TAS
Reserve one hour
Subtract 5.7 gallons for cruise at 215 knots
Subtract 9.5 gallons for cruise at 237 knots
Combat radius is 555 miles and this from a carrier and it is based on flight test
I think that is what I read


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## Shortround6 (Jul 14, 2012)

as a comparison a P-47C with 305 gallons in the internal tank could use Emergency max power (2000hp) for 5 minutes and max continuous power (1625hp) for 20 minutes and burn a total of 93 gallons. 175 gallons was supposed to be good for 580 miles at 200-205mph IAS at under 12,000ft. leaving a 37 gallon reserve (36 minutes give or take 5 minutes depending on altitude). This from the charts. 

Obviously the Army wasn't planning on using a 200mph IAS cruise at under 12,000ft to get the fighters back to base or the P-47 could have done the job with 305 gallons internal and a couple of drop tanks. 

Increasing the cruise to 200mph IAS (300mph true) at 25,000ft increases the fuel burn to 95 gallons an hour and shortens the "range" to 485 miles. 

Increasing the cruise to 225mph IAS (338mph true) at 25,000ft increases the fuel burn to 145 gallons an hour and shortens the "range" to 380 miles.

Most (all?) fighters did not take off on the drop tanks but used internal fuel for warm up, taxing, take-off and climb to a low but safe altitude to change over to the drop tanks. this 12-40 gallon take-off 'allowance" has to be subtracted from the "return" range.

Suitability of a fighter to under take certain missions depends on the actual conditions of the mission/s. Not a "benchmark" estimate of range.


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## timmy (Jul 14, 2012)

renrich said:


> Timmy raises an interesting point and very good photos. The F14 carried most of (or all) of it's missles, bombs in the tunnel and carrying it there was called conformally. That allegedly meant that there was no drag penalty and the air plane was as fast with the missles as without. I wonder if there was a somewhat similar situation with the Corsair and that the twin external 150 gallon tanks carried in the inverted gull section did not extract as much drag penalty as twin tanks did on an AC with a conventional wing?



There must be a real drag penalty having tanks behind the propeller line

Now North American Aviation which I guess had a very good understanding of the importance of good aerodynamics
Went as far as mounting the drop tanks on the p82 mostly on the outer edge of each wing of that aircraft
Which to me does not make any sense when they could have them all along the centre wing, as there is no under carriage in the way 

So my guess was that NAA thought those tanks would cause too much drag behind the propeller line?


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## VBF-13 (Jul 14, 2012)

renrich said:


> Timmy raises an interesting point and very good photos. The F14 carried most of (or all) of it's missles, bombs in the tunnel and carrying it there was called conformally. That allegedly meant that there was no drag penalty and the air plane was as fast with the missles as without. I wonder if there was a somewhat similar situation with the Corsair and that the twin external 150 gallon tanks carried in the inverted gull section did not extract as much drag penalty as twin tanks did on an AC with a conventional wing?


Yeah, that's what I surmised. Figure the JATO units hung there, as well. That was a stable spot on that aircraft. Those units looked not unlike those fuel tanks in Timmy's picture. Look at the yellow tips on those, how they're pointed to reduce the overall in-flight drag. Same went for any drag from the prop-wash, I'd imagine. That had to be negligible, at best.


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## renrich (Jul 15, 2012)

The chart did not say what the cruise speed was but an escort fighter is not going to cruise faster than the bomber being escorted. The four engined bombers cruised at around 175 MPH when loaded I think. The Navy fighters after disengaging from combat, if they knew where the carrier was going to be, would begin to slowly descend all the way back to the carrier, to save fuel and still maintain good airspeed. I expect that the AAF fighters would do the same if conditions allowed.


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## Shortround6 (Jul 15, 2012)

The escort fighters _DID_ cruise faster than the bombers. It takes too long to accelerate from 175-200mph up to 350mph to engage the enemy fighters when bounced. The escort fighters did "S" turns to keep speed up and still stay with the bombers. Even after the initial combat the escort fighters went home (at least a good part of the way) at high cruise speeds in case they were bounced again. Cruising at 175-200mph at under 15,000ft over western Germany or most of France gives the Luftwaffe too much of an advantage. Once over the Channel the speeds would be reduced and/or altitude lost.


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## bobbysocks (Jul 16, 2012)

timmy said:


> I'm sure I have read some where on this forum that if you had any protrusions like drop tanks behind the propeller line, it produced so much more wind resistance meaning less range. While mounting drop tanks outside the propeller line (P51) produces a lot less wind resistance, better range
> 
> Now I understand why Vought mounted the external tanks under the fuselage as it produces less stress on the wings. But if Vought was serious in adding range to the f4u wouldn't it be better mounting those tanks on the outer wings ? An F4U wing would certainly be strong enough
> 
> Anyway just wanted to add my thouhts


 
a little OT but the tanks on the 51 gave the plane ( and i imagine other ac with the same set up ) another occasional quirk. i remember stories from some 51 pilots to said the tanks created a little suction on the gear covers and every so often make the gear hard to retract. the fix was after taking off they would wag the wings or slip it side to side slightly to break the gear free to retract. i didnt think about too much until read in an old with franz stigler who said they did the same thing to 262 ( skid of slip it ) but on landing ...to lock the gear down. and i wondered if that had to do with the turbulence between the engine and the gear cover???

Luftwaffe Aces: Franz Stigler - HOGS Forum

_You weren’t in the 262 for very long were you? How many missions?

I had the 262 for over half a year…you know they build ‘em… one down in America.

Yeah! They flew one few months ago!

They got it up…I was there. If the pilot would have done what I told him…he wouldn’t have grounded it...

The wrecked the landing gear didn’t they?

Yeah, the undercarriage collapsed…

What did he do wrong?

What we always did…when we came in for a landing, and we were high yet, we sideslipped so the undercarriage would really lock.

And he didn’t?

It was common that it did that, you know…automatically. We had the same problem. Thing is, if we didn’t get the wheels even, you know, because the airplane exploded right there......_


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