tail end charlie
Senior Airman
- 615
- Aug 24, 2010
Wouldnt the carrier need a reinforced deck for a jug to land?
P-47N Thunderbolt vs. F4U-4 Corsair - Which was superior?
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FLYBOYJ
"THE GREAT GAZOO"
No. A TBM weighs just as much
renrich
Chief Master Sergeant
From Linnekin, "Eighty Knots to Mach 2" "The airplane had a huge turbosupercharger that by a combination of drag and mechanical power bleed off must have caused a substantial performance degradation at other than optimum altitudes. I know a couple of people who had an inadvertent encounter with four late model P47s one day in 1947. (Inadvertent, hell. The Bearcats jumped them. What did you expect? The P47s were there.) It was no contest----partly because the Bearcat, below ten thousand feet, could do absolutely everything better than anything with a propellor and at low altitudes could out accellerate most contemporary jets. Nonetheless, our guys said that AD Skyraiders and even SB2C Helldrivers flown aggressively had at other times given them as much trouble as the P47s."
Notice his use of " at other than optimum altitudes." That tells the story, IMO.
Takeoff distance comparisons- from "America's Hundred Thousand"
P47D-25 2540 feet
F4U4 710 feet
Notice his use of " at other than optimum altitudes." That tells the story, IMO.
Takeoff distance comparisons- from "America's Hundred Thousand"
P47D-25 2540 feet
F4U4 710 feet
Shortround6
Major General
It is not only weight but landing speed and sink rate.
For illustration sake I will make up a few numbers, feel free to plug in real numbers.
If, for instance, the P-47 hits the wires at 85knots and the TBM hits them at 75knots the P-47 needs the arresting gear to absorb/dissipate about 28% more energy assuming both weigh exactly the same. Energy goes up with the square of the speed. Subtracting 30 knots for the speed of the carrier gives you 55knots to 45 knots which means the P-47 is hitting the wires almost 50% harder than the TBM.
I don't know the sink rate for either plane, maybe the P-47 does come in faster but flatter, but if it doesn't?
A sink rate even 10% higher than the TBM means a 21% higher impact load on the deck.
While army planes were ferried on carriers there are good reasons why they weren't often operated AS carrier planes. There is more to it than adding a hook.
Hurricanes and Spitfires had relatively low wing loadings and stalling speeds and they had trouble.
For illustration sake I will make up a few numbers, feel free to plug in real numbers.
If, for instance, the P-47 hits the wires at 85knots and the TBM hits them at 75knots the P-47 needs the arresting gear to absorb/dissipate about 28% more energy assuming both weigh exactly the same. Energy goes up with the square of the speed. Subtracting 30 knots for the speed of the carrier gives you 55knots to 45 knots which means the P-47 is hitting the wires almost 50% harder than the TBM.
I don't know the sink rate for either plane, maybe the P-47 does come in faster but flatter, but if it doesn't?
A sink rate even 10% higher than the TBM means a 21% higher impact load on the deck.
While army planes were ferried on carriers there are good reasons why they weren't often operated AS carrier planes. There is more to it than adding a hook.
Hurricanes and Spitfires had relatively low wing loadings and stalling speeds and they had trouble.
Think mr. Linnekin is wrong here, turbos do not rob power from engine as mechanical superchargers do. And "must have caused" phrase is vague in any sense.
renrich
Chief Master Sergeant
TP, Linnekin is(or was) a retired Navy pilot who flew everything from a Stearman to an F4. He is an aeronautical engineer and a Navy test pilot. I wondered about that statement also but later ran across, somewhere, some information that proves his point. I would not want to go against him in technical knowledge. Page 106, "America's Hundred Thousand" The P47 had a two stage system with two blowers or compressors. The first stage was driven mechchanically by the engine. The second stage was driven by exhaust gasses. So there is mechanical bleed off.
Page 282 AHT, P47 N performance is depicted in the curves of Graph 33. Speed performance of the N model was down five to ten mph from the P47M because the P47N was bigger and heavier with the same engine but the real difference was in climb performance which at combat power was less than that of early Thunderbolts and at military power hardly exceeded 1700 FPM up to 20000 feet.
Have mentioned this before but one of my uncles was a Pilot Instructor in P39s and P47s. He told me that when they were bounced by Corsairs, they had no chance. That was undoubtedly at lower altitudes.
Page 282 AHT, P47 N performance is depicted in the curves of Graph 33. Speed performance of the N model was down five to ten mph from the P47M because the P47N was bigger and heavier with the same engine but the real difference was in climb performance which at combat power was less than that of early Thunderbolts and at military power hardly exceeded 1700 FPM up to 20000 feet.
Have mentioned this before but one of my uncles was a Pilot Instructor in P39s and P47s. He told me that when they were bounced by Corsairs, they had no chance. That was undoubtedly at lower altitudes.
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tail end charlie
Senior Airman
- 615
- Aug 24, 2010
I frequently get lost with abbreviations but figure it out eventually, what is a TBM please?
Messy1
Master Sergeant
Flyboy was referring to the TBM Grumman Avenger torpedo bomber.
Colin1
Senior Master Sergeant
Grumman Avenger
there were two designations
TBFs were built by Grumman themselves
TBMs were built by the Eastland Aircraft Division of GM
vikingBerserker
Lieutenant General
A P-47 needs almost a half mile of runway to take off? WOW!
Messy1
Master Sergeant
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Shortround6
Major General
Fine but the Corsair also used a two stage system. Both stages being mechanically driven by the engine. At low altitudes (under 10,000ft or so?) the 1st stage was disconnected and the engine was supplied by pretty much the same single stage supercharger as the P-47. With the waste gates on the turbo pretty much wide open at these low altitudes the the increase in back pressure would be fairly minor although there wouldn't be much in the way of exhaust thrust. Both planes used air to air inter-coolers between the 1st and second stages so the Corsair is hauling around that weight and bulk. Corsair does use a system where intake air can be routed from the air intakes to the inlet of the second stage without going through the rest of the plumbing/ ducting which may help. Some people claim that this is the difference between the F4F and the F6F.
renrich
Chief Master Sergeant
SR, this says the same as you but sounds different, I think. " The main blower was always speed up geared to the engine crankshaft and thus ran when ever the engine turned over. The auxiliary (second stage) blower and it's two sets of different speed up gearing could be clutched to and declutched from the crankshaft via a control in the cockpit." This was the system on the R1830 and R2800.
davparlr
Senior Master Sergeant
This is some advantage for the F4U. The P-47N offsets this somewhat with great range. There were not very many places the P-47N could not reach in the Pacific when the P-47N and the F4U-4 became available.
Below 10k ft, I would agree, but from 10k up, the extra 800 to 1000 hp of the P-47M certainly would mitigate the 8% increase in wing loading. I think the maneuvering advantage is still with the F4U but it would not be a big advantage.
windswords said:
I don't think landing is the issue. The four times take off distance of the P-47 vs. F4U is the issue!
A Bearcat below 10k? I am not sure this adds to the debate for the reasons you stated. Would a F4U-4 do better? Unknown.renrich said:
Navy pilots talking about an encounter with an Army aircraft, can you believe any other outcome would be stated? Army pilots talking about Navy aircraft are just unbelievable. I could easily believe a lightly loaded AD, with its powerful engine (although still not as powerful as the P-47N) and high lift wings could be a formidable turning dogfighter. It could turn, but couldn't run. The SB2C is a toad and any model P-47 pilot would have to be asleep to be tested by that plane. It may be able to turn, but it was slow.
And you nailed the problem.
There is a problem with this comparison. The weight comparison of the P-47M to N shows a difference of 2000 lbs. The P-47N has a basic weight of 500 lbs more than the M. Apparently the tested N had a much higher load factor than the M. When I corrected the P-47N basic weight for fuel and ammo of the F4U-4 used in AHT, the gross weight of the P-47N was13,872 lbs or 2828 lbs less than the tested aircraft in the AHT chart. Obviously, this is a significant number, almost a ton and a half, affecting both airspeed and especially climb. Using this data, I guessed the climb of the P-47N would be around 4000 ft/min, or similar but slightly less than the F4U-4. Air force test of a P-47N at a gross weight of 15,790 lbs showed a SL climb rate of 3580 ft/min. This is still almost 2000 lbs less than the P-47N adjusted to the F4U-4 weight. Airspeed impact is less and I have not corrected that value.
windswords
Airman
P47D-25 2540 feet
F4U4 710 feet
Is this a takeoff fully loaded from dry land for the Corsair? Or a carrier going 30 knots into a 30 knot headwind? Because even the Essex class carriers were 872 feet long overall. The Bolts takeoff is undoubtedly laden down with bombs rockets and drop tanks. I've seen restored examples get off the ground in much shorter distances than that.
"There has never been a vessel long enough to launch a P-47 of any variety with a full load of fuel to take advantage of the range differential - so that would be a spurious argument."
Well to argue the Corsair is superior just because it was designed for carrier operations is just as spurious, which was the point I was trying to make. And this doesn't change the fact that the Bolt had a 1000 mile greater range.
"Even the 8th AF jugs were far below the air to air ratio of the Mustang over Europe."
I don't have those ratios but IIRC the Jug shot down more German planes than any other type - at least for the Americans. So the ratio couldn't have been that bad. A lot pilots became aces in the Bolt, including those who later switched to Mustangs.
"The Jug was out rolled by the Fw 190 below 350mph and the Fw 190 was about as fast"
Gotta keep your speed up!
" - the 109 out climbed (by far) and out turned below 25,000 feet."
Again - maneuver vs energy. I'll take energy every time.
F4U4 710 feet
Is this a takeoff fully loaded from dry land for the Corsair? Or a carrier going 30 knots into a 30 knot headwind? Because even the Essex class carriers were 872 feet long overall. The Bolts takeoff is undoubtedly laden down with bombs rockets and drop tanks. I've seen restored examples get off the ground in much shorter distances than that.
"There has never been a vessel long enough to launch a P-47 of any variety with a full load of fuel to take advantage of the range differential - so that would be a spurious argument."
Well to argue the Corsair is superior just because it was designed for carrier operations is just as spurious, which was the point I was trying to make. And this doesn't change the fact that the Bolt had a 1000 mile greater range.
"Even the 8th AF jugs were far below the air to air ratio of the Mustang over Europe."
I don't have those ratios but IIRC the Jug shot down more German planes than any other type - at least for the Americans. So the ratio couldn't have been that bad. A lot pilots became aces in the Bolt, including those who later switched to Mustangs.
"The Jug was out rolled by the Fw 190 below 350mph and the Fw 190 was about as fast"
Gotta keep your speed up!
" - the 109 out climbed (by far) and out turned below 25,000 feet."
Again - maneuver vs energy. I'll take energy every time.
tail end charlie
Senior Airman
- 615
- Aug 24, 2010
Thanks guys.
Hi, ren,
This:
is in collision with this:
So I'd go with AHT, and claim that mechanical bleed off is minor issue for turbocharged R-2800 vs. mech supercharged 2800 - and power charts.
Surely, the 'substantial performance degradation at other than optimum altitudes.' needs to be backed by some good numbers - for sheer power of P-47's engine Germans Japanese would've killed for in 1943-45.
Back to mr. Linnekin, while acknowledging his experience knowledge:
#1 thanks for pointing out he was naval aviator, therefore his view about P-47 need to be taken with a grain of salt - both because of inexperience about army planes, and possible bias
#2 (again) phrase 'must have caused' is not to be expected as a view expressed by a professional
This:
is in collision with this:
So I'd go with AHT, and claim that mechanical bleed off is minor issue for turbocharged R-2800 vs. mech supercharged 2800 - and power charts.
Surely, the 'substantial performance degradation at other than optimum altitudes.' needs to be backed by some good numbers - for sheer power of P-47's engine Germans Japanese would've killed for in 1943-45.
Back to mr. Linnekin, while acknowledging his experience knowledge:
#1 thanks for pointing out he was naval aviator, therefore his view about P-47 need to be taken with a grain of salt - both because of inexperience about army planes, and possible bias
#2 (again) phrase 'must have caused' is not to be expected as a view expressed by a professional
renrich
Chief Master Sergeant
TP, there is no doubt that Linnekin is speculating about the P47 because I feel sure he never flew one or studied one extensively. I don't think however that his statement is inaccurate, as I understand it. The first blower was driven by the crankshaft so would that not bleed off power? The P47 was a big airplane so that would cause a lot of drag, would it not? Anyway, the P47N had very good performance above 25000 feet up to something over 30000 feet. But it was not such a good performer at lower altitudes, especially below 20000 feet. Something must have caused that. The F4U4 is about 15-20 mph faster than the P47N at very low altitudes and the Thunderbolt only surpasses the Corsair in that measurement above 25000 feet. That rate of climb in military power of 1700 FPM up to 20000 feet for the P47N is indicative of something also, probably weight.
If top speed is the only determinant in the effectivenss of a fighter's performance, which it is not, the P47N only betters the F4U4 above 25000 feet. To me, if one fighter climbs better, is faster, accelerates better and is more maneuverable from sea level to 25000 feet and the other only begins to outperform the first one at 25000 feet up to around 35000 feet, my choice is clear as to which is "best." I guess that depends on your definition of best.
The P47N, as I understand it, was designed to be a long range, high altiude, escort fighter for the PTO. It sounds like it would have been good at that if the B29s were bombing from 30-35000 feet. In the event the B29s found that their very high altitude bombing was not effective so the mission of the P47N was diminished in importance.
If the question is, which is the best high altitude, long range, escort fighter, the winner is the P47N. If the question is, which is the best all around, carrier borne or land based, fighter, fighter bomber, ACM fighter at altitudes where most ACM took place and defender of the fleet, my choice would be F4U4.
If top speed is the only determinant in the effectivenss of a fighter's performance, which it is not, the P47N only betters the F4U4 above 25000 feet. To me, if one fighter climbs better, is faster, accelerates better and is more maneuverable from sea level to 25000 feet and the other only begins to outperform the first one at 25000 feet up to around 35000 feet, my choice is clear as to which is "best." I guess that depends on your definition of best.
The P47N, as I understand it, was designed to be a long range, high altiude, escort fighter for the PTO. It sounds like it would have been good at that if the B29s were bombing from 30-35000 feet. In the event the B29s found that their very high altitude bombing was not effective so the mission of the P47N was diminished in importance.
If the question is, which is the best high altitude, long range, escort fighter, the winner is the P47N. If the question is, which is the best all around, carrier borne or land based, fighter, fighter bomber, ACM fighter at altitudes where most ACM took place and defender of the fleet, my choice would be F4U4.
davparlr
Senior Master Sergeant
ETO Aircraft shot down by P-47s 3082, for the P-51, 4950.
Hi, ren 
I'm not advocating that P-47N was so many times better than F4U-4(it was not), merely putting out that mr. Linnekin's opinion about P-47 is only opinion (despite the credit the man deserves about other planes). Perhaps quoting some real P-47 expert would've been better choice
Re. power bleed off: that issue is of minor weight re. P-47, since it applies much more on Merlins, DBs, Jumos, R-2800s with mech supercharging etc.
Re. drag of P-47: drag itself means nothing, if airplane has enough power to overcome it. We all know that P-47 was fastest combat-ready plane when introduced, and it's speed was always high - thanks to turbo mostly.
I'm not advocating that P-47N was so many times better than F4U-4(it was not), merely putting out that mr. Linnekin's opinion about P-47 is only opinion (despite the credit the man deserves about other planes). Perhaps quoting some real P-47 expert would've been better choice
Re. power bleed off: that issue is of minor weight re. P-47, since it applies much more on Merlins, DBs, Jumos, R-2800s with mech supercharging etc.
Re. drag of P-47: drag itself means nothing, if airplane has enough power to overcome it. We all know that P-47 was fastest combat-ready plane when introduced, and it's speed was always high - thanks to turbo mostly.
