Corsair and Hellcat in Europe

[DarrenW]

I know that critical altitudes are lower for higher power settings. I was thinking about detonation, which occurs as a function of manifold pressure (and resulting heat): I figured if the manifold pressure could get higher without detonation...

Yes, what you said in bold is the key to it. The "powers to be" decide on the safe operating limits of a particular engine while using a certain type of fuel or an emergency boost system (ADI, MW50, GM1...what have you). When you lower the chances of detonation (in this example by raising the octane rating) there's less chance of damage to the engine, so it can be safely boosted to higher manifold pressure levels which in turn gives increased output power safely and reliably. The same engine without higher octane fuel or an emergency boost system could still operate at the new authorized boost levels but major damage will most likely occur.

That's pretty good, so with a climb rate of 2900 feet per minute, you'd now see 3400, and for 3200, you'd now get to 3700, and for 3650, you would be able to get up to around 4150?

Actually I was talking about a 10" Hg increase from a combat power setting (60" to 70" Hg), which might yield about a 3,700-3,800fpm climb rate at sea level. Not too shabby.

Are those figures addable to each other? For example 500 fpm from 44-1 fuel; 300 fpm for stripping down so 300+500 = 800? Or is there some other variable?

Best if this is done by an using an example. If we start with a standard Corsair that can climb at 3,200fpm in combat power, converting it to a "land-based" version might allow for a climb rate of 3,500fpm (if we use the estimated 300fpm increase supplied by drgondog). By running 44-1 fuel in this same converted aircraft the climb rate may theoretically reach 4,000fpm.

 

[davparlr]

I think both the F6F and F4U could have been formidable at lower altitudes and if they were well flown, but they would be handicapped at some of the high altitude combat arenas of Europe. Both the F6F and F4U-1/1D engines began to loose power precipitously above 20-24k ft. whereas the P-51 starts losing significant power at 30k and, of course, the P-47 engine was flat rated up to 28-33k ft. The F4U-4 has much better high altitude performance but did not become operational until around VE day.

 

[DarrenW]

I think both the F6F and F4U could have been formidable at lower altitudes...

Yep, and if they were able to use 150 octane fuel to allow 70" Hg of manifold pressure the critical altitude in high blower would theoretically lower even further to around 13-14,000ft, down from 18-20,000ft while operating at 60" Hg. This would undoubtedly enhance their already excellent low to medium altitude fighting ability.

 

[Zipper730]

He convinced his manager they needed an expensive surveyors measuring device, I don't know what it was, and started measuring the plane.

I think you might be thinking of a theodolite...

From what I can tell it would be hard to beat the view perched way up high and forward in a F6F

Yeah, I amended that in the earlier post.

If it just specualtion, you could look at several civilian Corsairs or Hellcats of taoday. Some have been de-navalized to an extent, and most have had armor remove as well as guns and unnecessary hardware items that drop things from wings or belly. You can't do that today as a civilian.

A person's not allowed to modify a former military aircraft as a racer?

 

[Zipper730]

If a lesser turning aircraft can get into what is today called the "control zone"

I'm surprised they don't just call it the killing zone

the Zero could out turn pretty much everything it faced, however that doesn't make it impervious to another type getting into position and passing on a dose of lead poisoning from a turning fight.

Yeah, it kind of reminds me of a time where I was playing basketball (I'm not that good at it), and was able to block a guy's shot despite him being taller than me and able to jump higher than I could (I was already in the air as he just started to leave the ground -- popped the ball right out his hand).

First there are four ways in which a turn is measured or discussed, those being instantaneous / sustained and rate / radius. When an aircraft starts a max performance turn at high speed the pilot pulls to the aircrafts G limit. Pulling to the G limit results in a turn of a X degrees per second. As the aircraft slows it gets to what today is called corner velocity. That is the speed at which max degrees per second is obtained, also coincidentally enough it's the speed at which an abrupt full aft stick will not result in an over G.

Yeah, it's the lowest speed where enough lift exists to pull the maximum rated g-load without stalling the aircraft.

Below this speed if airspeed is continued to be bled off (energy depleting) then The degrees per second stay about the same up to a certain point then start to slack off.

G-load drops, lower speed still means the turning circle remains tight at first until the lift available to make it turn reach such a low level that you're barely able to turn at all?

 

[BiffF15]

I'm surprised they don't just call it the killing zone
Yeah, it kind of reminds me of a time where I was playing basketball (I'm not that good at it), and was able to block a guy's shot despite him being taller than me and able to jump higher than I could (I was already in the air as he just started to leave the ground -- popped the ball right out his hand).
Yeah, it's the lowest speed where enough lift exists to pull the maximum rated g-load without stalling the aircraft.
G-load drops, lower speed still means the turning circle remains tight at first until the lift available to make it turn reach such a low level that you're barely able to turn at all?

Zipper,

The control zone was previously known as the riding position do to the fact you have control over or are "riding ", like a horse, your opponent. Just because you have maneuvered into the control zone does not guarantee you a kill. Employing a gun against a skilled opponent is not easy by any means. Against other 4th generation fighters I am / was confident I could survive until the floor became a factor. And this was against guys who were very good, and had almost instantaneous feedback on whether their shots were good enough for a kill. There are levels to a BFM engagement that would literally take guys years to get to a doctorate level of understanding. Realize I boil down what I share in here, but there are volumes of background data that goes with it that doesn't get passed. Also realize I censor what I say as well in order not to share something that could be used against us or our allies.

To answer your question yes. Imagine an airplane about 5 knots above the stall. He is able to turn but using only a few degrees of bank. His turn radius would be large, and his rate low. Add more speed and radius continues to decrease and rate continues to rise. Continue this trend and at some point you will get to his min radius. Above that speed his turn circle will start to INCREASE in size, and will continue to do so up to his max speed. Rate will continue to increase until at some speed it reverses to decrease.

The above info covers the raw data that governs a dogfight / BFM (basic fighter maneuver) fight. Understanding those facts, how your and your opponents aircraft operate with regards to those rules, where you are in relationship to each other and the ground, all coalesce into determining the winner. Luck is always a factor be it good or bad.

Cheers,
Biff

 

[Zipper730]

Grumman's chief test pilot, Corky Meyer, has said in print (Flight Journal) that the Hellcat and Corsair flew side by side when at the same power levels when HE tested it except in the main stage (where it was 5 - 6 mph slower since the Hellcat didn't use ram air to avoid carburetor icing
. . .
the F6F was designed without ram air to the carburetor on purpose, and Grumman would not add ram air under any circumstances.

Though I figure this will probably sound stupid, I'm curious why ram air would cause carburetor icing? I ask because I'd have figured that an increase in ram compression would cause a slight increase in pressure (and temperature on that note).

And from a pure hypothetical "what if" performance benefit estimate (as this thread is sort of based on how much extra performance could be squeezed out of an F6F and F4U if they were used in the ETO, were de-navalized, used 44-1 fuel, etc), I'm curious if this would have required a subtle difference or a massive redesign more or less.

 

[Zipper730]

To answer your question yes. Imagine an airplane about 5 knots above the stall. He is able to turn but using only a few degrees of bank. His turn radius would be large, and his rate low. Add more speed and radius continues to decrease and rate continues to rise. Continue this trend and at some point you will get to his min radius. Above that speed his turn circle will start to INCREASE in size, and will continue to do so up to his max speed. Rate will continue to increase until at some speed it reverses to decrease.

Makes sense

The control zone was previously known as the riding position do to the fact you have control over or are "riding ", like a horse, your opponent.

Oh, okay

Just because you have maneuvered into the control zone does not guarantee you a kill.

I know that, from what I gather, it simply means the parameters simply exist to make it possible.

There are levels to a BFM engagement that would literally take guys years to get to a doctorate level of understanding.

And it's more than understanding it, it's the ability to understand it and *do* it...

Realize I boil down what I share in here, but there are volumes of background data that goes with it that doesn't get passed. Also realize I censor what I say as well in order not to share something that could be used against us or our allies.

I figured that would be the case.

Luck is always a factor be it good or bad.

Very true!

 

[Zipper730]

I am not so sure. There are many tests from World War II with data on both aircraft, even comparisons, and the Hellcat is slower. An example:

http://www.wwiiaircraftperformance.org/fw190/ptr-1107.pdf

Also, I would expect the instruments to be calibrated accordingly if the pitot tube is setup at a different height. Having said that, manufacturers stated that the performance could vary by 10% IIRC, thus there could be some "overlap".

Yeah, from what I remember, the critical altitude of the F4U-1 was around 23800' and 23200' for the F6F-3. I'm not sure what power-setting that's at, but it might be normal rated. If they're off by 10%, that would account for a critical altitude of 25000 feet for the F6F & F4U.

That said, you'd think for combat tests you'd make sure all the numbers and figures were pristine and not messed up in anyway.

 

[MIflyer]

Here is a diagram of the R-2800 two stage supercharger.

 

[Navalwarrior]

Granted, the F4U was a terrific performer, but it was extensively used as a ground attack aircraft in the PTO, not just by the USN, but also RNZAF and FAA, so its air-to-air combat figures are generally going to be lower than the Hellcat.



I can't really agree, since who would be operating it? The USN didn't have a great presense in the ETO and the FAA didn't use the Corsair extensively in that theatre. The USAAF certainly had its own performers, so while F4Us might have made an impact, I doubt there would have been a desire to spur development of it specially to suit the needs of the ETO. Its performance wasn't that much greater than ETO fighters.

Resp:
I know this is an old thread, but the USAAF 8th AF force was suffering severe losses as it flew progressively closer to bombing Germany. So much so that Gen Hap Arnold put out a letter in June 1943 . . . directing that a fighter either be developed or an existing fighter modified . . . to provide deep penetration escort of his bombers.
In May 1943 the USAAF hosted a 'Joint Fighter Meet' where all services (USAAF, USN, RAF etc) were invited to fly any of the fighters present (P-47, F4U-1, Seafire, etc). Every Army pilot who flew the Corsair gave it raved reviews, as the Corsair easily outmaneuvered their primary fighter . . . the P-47.
I spent a lot of time evaluating the F4U for the ETO. This is what I looked at:
1. Availability: Yes, due to carrier landing issues, the USN relied on the F6F. USMC and FAA (Royal Naval Air Force) began receiving the F4U-1/F4U-1A and Corsair and Corsair II, respectively. So 25 to 30 F4U-1As could have provided a Squadron, for testing/evaluation in the ETO.
F4U-1A:
2. Range
- Internal/External fuel. One 237 gal fuselage self sealing tank located just forward of cockpit; 2 wing tanks of 62 gal each (2 X 62 = 124 gal) that are non-self sealing. How long would it take to convert to self-sealing?
- Extertnal fuel (drop tanks); One 160/171 centerline drop tank (additional range: ? )
3. Cruising speed: 186 mph
Using internal fuel at the Cruising speed of 186 gets @ 1015 miles. However, Naval operations rarely require altitudes above 15,000 ft. 8AF normally operated at 17,000 to 30,000 ft. Also, to be able to engage fast moving Luftwaffe fighters . . . USAAF Fighters (P-47, P-38 and later P-51s) were required to fly at least half of their mission at higher speeds (thus using up more fuel). To keep up their speed and to remain close to the bombers, they flew zigzag formations at least 3,000 ft above the bombers (example: 27,000 ft above 24,000).
4. Fuel Consumption: @ 195 gal per hour during normal-rated cruise (which was somewhat high). So it appears that if the two wing tanks were made self sealing, it range could be extended. But by how much?
5. Maximum service ceiling (high altitude required to cover high flying B-17/B-24s). 15,000 ft vs 27,000 ft. Result: Additional fuel consumed to get to the higher altitude.
6. Maximum speed: 417 mph
7. Service ceiling: 20,000 ft (a living Marine F4U combat pilot/instructor I spoke with took all of his students to 30,000 ft, but it took some time to do so. While flying CAP for US fleet in 1945 their normal cruising altitude was 10,000 to 14,000 ft).
8. Armament: Six 50 cal MG (three in each wing)
9. Even though the F4U used the same engine as the USAAF's P-47, the Corsair had a less advanced carburetor than the Thunderbolt and the F4U would require a major rebuild to include the advanced carburetor.

Keep in mind that the P-47 didn't start receiving its first drop tank (single 75 gallon belly tank) until late Sept/early Oct 1943. The single tank gave them @ 10 min more flying time before they had to turn for home. The Merlin P-51B Mustangs first flew long range escort in the ETO in Dec 1943.

So could a test bed of say 25 Corsairs be delivered to the 8th AF for evaluation? 25 FAA Corsairs be rerouted to England via a British carrier for the USAAF 8th AF? I know, I am dreaming! But June to Dec is just less than 6 months. Plenty of time for trials.
If we use the closest fighter base in England, the F4U could easily have flown a mid-distance relay mission? But what was really needed is a fighter to go as far as the bombers, and back. German factories were the main targets.

Three Problem areas:
1 - Cruising speed too slow for adequate interception to protect bombers.
- Internal fuel insufficient for return trip based on one single 237 gal self-sealing tank.
2 - internal fuel with two converted wings to self sealing . . Insufficient ?
3 - Carburetor cannot perform well at the high altitudes of 22,000 to 28,000 ft to take on current Luftwaffe fighters.

Also,
Can the Corsair out climb a ME 109 or FW 190 to gain advantage? The pilots at the Joint Fighter Meet, Elgin, FL that flew the F4U-1 in mid 1943 . . . but were much lower than 20,000 ft. Yes, in close combat the F4U can easily get behind an early FW 190, as demonstrated with a captured Focke Wulf 190 in air to air manuvers in 1944.

The F4U was designed around naval requirements. The FAA Hellcats just had to keep the Luftwaffe off the FAA's attacking planes. It did not require 27,000 ft to do its job. The USN used the F6F-5 Hellcat during the landings of Southern France 17 days after Allies landed at Normandy. In this role, Hellcats proved very capable air to air and air to ground engagements.

 

[P-39 Expert]

Resp:
I know this is an old thread, but the USAAF 8th AF force was suffering severe losses as it flew progressively closer to bombing Germany. So much so that Gen Hap Arnold put out a letter in June 1943 . . . directing that a fighter either be developed or an existing fighter modified . . . to provide deep penetration escort of his bombers.
In May 1943 the USAAF hosted a 'Joint Fighter Meet' where all services (USAAF, USN, RAF etc) were invited to fly any of the fighters present (P-47, F4U-1, Seafire, etc). Every Army pilot who flew the Corsair gave it raved reviews, as the Corsair easily outmaneuvered their primary fighter . . . the P-47.
I spent a lot of time evaluating the F4U for the ETO. This is what I looked at:
1. Availability: Yes, due to carrier landing issues, the USN relied on the F6F. USMC and FAA (Royal Naval Air Force) began receiving the F4U-1/F4U-1A and Corsair and Corsair II, respectively. So 25 to 30 F4U-1As could have provided a Squadron, for testing/evaluation in the ETO.
F4U-1A:
1. Range
- Internal/External fuel. One 237 gal fuselage self sealing tank located just forward of cockpit; 2 wing tanks of 62 gal each (2 X 62 = 124) that are non-self sealing. How long would it take to convert to self-sealing?
- Extertnal fuel (drop tanks); One 160/171 centerline drop tank (range: )
2. Cruising speed: 186 mph
Using internal fuel at the Cruising speed of 186 gets @ 1015 miles. However, Naval operations rarely require altitudes above 15,000 ft. 8AF normally operated at 17,000 to 30,000 ft. Also, to be able to engage fast moving Luftwaffe fighters . . . USAAF Fighters (P-47, P-38 and later P-51s) were required to fly at least half of their mission at higher speeds (thus using up more fuel). To keep up their speed and to remind close to the bombers, they flew zigzag formations at least 3,000 ft above the bombers (example: 27,000 ft above 24,000).
3. Fuel Consumption: @ 195 gal per hour during normal-rated cruise (which was somewhat high). So it appears that if the two wing tanks were made self sealing, it range could be extended. But by how much?
4. Maximum service ceiling (high altitude required to cover high flying B-17/B-24s). 15,000 ft vs 27,000 ft. Result: Additional fuel consumed to get to the higher altitude.
5. Maximum speed: 417 mph
6. Service ceiling: 20,000 ft (a living Marine F4U combat pilot/instructor I spoke with took all of his students to 30,000 ft, but it took some time to do so. While flying CAP for US fleet in 1945 their normal cruising altitude was 10,000 to 14,000 ft).
7. Armament: Six 50 cal MG (three in each wing)
8. Even though the F4U used the same engine as the USAAF's P-47, the Corsair had a less advanced carburetor than the Thunderbolt and the F4U would require a major rebuild to include the advanced carburetor.

Keep in mind that the P-47 didn't start receiving its first drop tank (single 75 gallon belly tank) until late Sept/early Oct 1943. The single tank gave them @ 10 min more flying time before they had to turn for home. The Merlin P-51B Mustangs first flew long range escort in the ETO in Dec 1943.

So could a test bed of say 25 Corsairs delivered to the 8th AF for testing? 25 FAA Corsairs be rerouted to England via a British carrier for the USAAF 8th AF? I know, I am dreaming! But June to Dec is just less than 6 months. Plenty of time for trials.
If we use the closest fighter base in England, the F4U could easily have flown a mid-distance relay mission? But what was really needed is a fighter to go as far as the bombers, and back. German factories were the main targets.

Three Problem areas:
1 - Cruising speed too slow for adequate interception to protect bombers.
- Internal fuel insufficient for return trip based one single 237 gal self-sealing tank.
2 - internal fuel with two converted wings to self sealing . . Insufficient ?
3 - Carburetor cannot perform well at the high altitudes of 22,000 to 28,000 ft to take on current Luftwaffe fighters.

Also,
Can the Corsair out climb a ME 109 or FW 190 to gain advantage? The pilots at the Joint Fighter Meet, Elgin, FL that flew the F4U-1 in mid 1943 . . . but were much lower than 20,000 ft. Yes, in close combat the F4U can easily get behind an early FW 190, as demonstrated with a captured Focke Wulf 190 in air to air manuvers in 1944.

The F4U was designed around naval requirements. The FAA Hellcats just had to keep the Luftwaffe off the FAA's attacking planes. It did not require 27,000 ft to do its job. The USN used the F6F-5 Hellcat during the landings of Southern France 17 days after Allies landed at Normandy. In this role, Hellcats proved very capable air to air and air to ground engagements.

Great post Naval.

Corsair was truly a war winning fighter with a big place in history, and much deservedly so. Ironic to me that the Marines, who were famous for getting Navy leftovers, were the first to get arguably the best fighter plane in the world in February 1943 at Guadalcanal. Which they used to dramatic effect until the end of the war, and then on into Korea.

But it's internal fuel capacity would preclude it from escorting bombers in the ETO. If the Thunderbolt couldn't do it with 300 gallons internal, then the F4U wouldn't have a chance with 237 gallons. Even if the wing tanks were made self sealing (at a cost of, say 20 gallons) then the Corsair would still have only 340 gallons internal. Using 190 gallons per hour at normal power would only add another half hour or so with the additional wing tanks.

Then again, ETO escort was done in relays. Even the Mustang didn't take the bombers all the way to the target and back. So the Corsair could have helped like the Thunderbolt and early Lightnings, but it wouldn't solve the ultimate problem.

When Hap Arnold wrote his letter in June '43 wanting a long range escort fighter he had to have known that P-38Hs would be coming in October and the Mustang would arrive in December, surely long before any new or existing fighter could be produced or modified.

 

[Navalwarrior]

Great post Naval.

Corsair was truly a war winning fighter with a big place in history, and much deservedly so. Ironic to me that the Marines, who were famous for getting Navy leftovers, were the first to get arguably the best fighter plane in the world in February 1943 at Guadalcanal. Which they used to dramatic effect until the end of the war, and then on into Korea.

But it's internal fuel capacity would preclude it from escorting bombers in the ETO. If the Thunderbolt couldn't do it with 300 gallons internal, then the F4U wouldn't have a chance with 237 gallons. Even if the wing tanks were made self sealing (at a cost of, say 20 gallons) then the Corsair would still have only 340 gallons internal. Using 190 gallons per hour at normal power would only add another half hour or so with the additional wing tanks.

Then again, ETO escort was done in relays. Even the Mustang didn't take the bombers all the way to the target and back. So the Corsair could have helped like the Thunderbolt and early Lightnings, but it wouldn't solve the ultimate problem.

When Hap Arnold wrote his letter in June '43 wanting a long range escort fighter he had to have known that P-38Hs would be coming in October and the Mustang would arrive in December, surely long before any new or existing fighter could be produced or modified.

Cont:
One other thought, how much extra room would a FG-1A have without the folding wing assemblage? Would there have been room for additional internal storage for fuel tanks? Also, were the non-folding wing variants lighter than the standard F4U-1A?

 

[swampyankee]

Cont:
One other thought, how much extra room would a FG-1A have without the folding wing assemblage? Would there have been room for additional internal storage for fuel tanks? Also, were the non-folding wing variants lighter than the standard F4U-1A?

I'd have to dig through the drawings to try to estimate both, but I'd not be surprised if the wing folding mechanism and required structural mods added over a hundred pounds to the Corsair's wing weight. I'd use some of that saving to put in a cockpit floor, which would probably save dozens of pounds in weight due to lost pencils.

 

[Navalwarrior]

I'd have to dig through the drawings to try to estimate both, but I'd not be surprised if the wing folding mechanism and required structural mods added over a hundred pounds to the Corsair's wing weight. I'd use some of that saving to put in a cockpit floor, which would probably save dozens of pounds in weight due to lost pencils.

Resp:
Seriously, would there be room for self sealing fuel tanks. If so, is there a way to estimate number of gallons of fuel?

 

[swampyankee]

Resp:
Seriously, would there be room for self sealing fuel tanks. If so, is there a way to estimate number of gallons of fuel?

I couldn't even guess how much self-sealing fuel tankage could be added by removing the wing-fold mechanism. For one, it would depend on how the wing was redesigned with the folding removed. I'd guesstimate that about 15% of the 124 gallons in the wing tanks would be lost due to self-sealing. Adding another tank -- perhaps under the cockpit (another reason to put a floor in) -- could add a few more gallons.

 

[Navalwarrior]

I couldn't even guess how much self-sealing fuel tankage could be added by removing the wing-fold mechanism. For one, it would depend on how the wing was redesigned with the folding removed. I'd guesstimate that about 15% of the 124 gallons in the wing tanks would be lost due to self-sealing. Adding another tank -- perhaps under the cockpit (another reason to put a floor in) -- could add a few more gallons.

Cont:
There must be some engineering/assembly drawings that you could compare to a standard folding wing F4U. We don't have to have an answer today. Thanks.

 

[Shortround6]

The existing fuel tanks were in the wing leading edge outboard of the guns. I beleive they were integral tanks. Rear of tank was the main spar and the leading edge skin was top, bottom and front. Wing ribs were the ends. There appear to be multiple ribs in the tank area so fitting self sealing tanks/cells, while possible, would not be easy.
The fixed wing Corsairs were a simple conversion. They left out the hydraulic actuators and basically bolted the existing folding wing part to the fixed wing part. The matching bulkheads in each part also acting as wing ribs so you can't eliminate both of them.
Please look at a cutaway drawing. There isn't a lot of room in an F4U wing that isn't being used until you get outboard of the ammunition storage. The wing center section under the cockpit was a multi cell structure that I believe was welded. I don't know if you could put a tank in the wing root between the fuselage and the landing gear wheel well which is about the only large unused space in the wing inboard of the guns.

 

[nuuumannn]

Great post Naval.

It is and it isn't. While Naval warrior's post certainly goes into detail, it doesn't in fact dispute my question of who was to use it at the time in the ETO. By 1944 the desire for a long range escort was being met by the P-51, P-47 and P-38, ground attack was being handled by aircraft like the Beaufighter and Typhoon, with the Tempest as a supreme low altitude fighter entering service and the likes of the Spitfire XIV on the way as a great all rounder, excellent performance down low and up top, the Allies have some serious capability at their disposal. Now sure, every airframe counts and there's no doubt the Corsair would have been welcome in larger numbers, but if Corsairs were being diverted to the ETO, where are they not being used? There was a need for them in the Pacific, so that's where they were best served. Not even a Corsair can be in two places at once.

 

[Dana Bell]

Nearly one fourth of the approximately 4,000 FG-1s were delivered without folding wings in a successful effort to save weight. The wing structure could not accommodate additional fuel tanks - the maximum wing tankage had been designed around the leading edge "wet wing" tanks, which leaked under most conditions. Efforts to replace the wet wing with sealed tanks were abandoned because the small amount of additional fuel wasn't worth the increased weight.

Cheers,



Dana