Was the F4U Seriously Considered for the European Theatre ?

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.

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

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.

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

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.

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.

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!

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?

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.

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.

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 ?

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

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.

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!

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.

renrich · Jul 13, 2012

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

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...

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.

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

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!

Was the F4U Seriously Considered for the European Theatre ?

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