SHOULD the P39 have been able to handle the Zero? Was it training or performance?

[P-39 Expert]

Could you possibly expand on the comment about the Army not wanting the Russians to have that -93 power plant? Thanks, Hansie

I can't prove this with facts, but I do know that while the Russians were our ally at the time, we still had HUGE political/ideological differences with the communists. We (including Britain) were perfectly happy to let the Nazis and the Communists destroy each other wholesale as long as the Nazis didn't actually knock the Russians out of the war. This leads me to believe that we were parceling out the war products we were giving them under lend-lease so as to give them good, serviceable planes competitive with their Luftwaffe adversaries, but not our very best cutting edge technology. We wanted them to wear down the Nazis prior to our invasion at D-Day. Just my 2 cents worth. Does this help?

 

[wuzak]

It probably took so long because they were sorting out other issues and production.

As a development engine, the -93 would likely have been cleared for flight before it passed the endurance test, which is what was required before production commenced and the engine put in service.

The test for flight clearance was less stringent than the full type test.

 

[P-39 Expert]

This is not a "fact" and you have posted it twice. Yaeger was a Bell employee in the post war years, he broke the sound barrier in a Bell X1. He could only possibly favour it as a WW2 aircraft considering the performance of other high performance jets he flew. Basically he preferred the P-39 until he flew the P51 but in WW2 he only flew those two as far as I have read. Did he ever attempt any violent manoeuvres with all ammunition spent, for example?

He most definitely said the P-39 was his favorite plane (until the P-51B arrived) both in his book and on video, both late in his career. And he also stated that he could not make a P-39 tumble. The video is on youtube.

 

[P-39 Expert]

The impression I'm getting from all this discussion is that the P39 was a day late and a dollar short. For the western allies there was always something more suited for any role that could be found for it and by the time it had improved something else better was in service.

It was on the eastern front where it found its niche, it's drawbacks outweighed by it's advantages.

More like in production in time for the beginning of WWII, unlike the P-38, P-47 and P-51. We would have been hard pressed without the P-39 in 1942. Only the P-39, P-40 and F4F were available at the beginning. So, more like a day early, don't know about the dollar short.

 

[Hansie Bloeckmann]

I can't prove this with facts, but I do know that while the Russians were our ally at the time, we still had HUGE political/ideological differences with the communists. We (including Britain) were perfectly happy to let the Nazis and the Communists destroy each other wholesale as long as the Nazis didn't actually knock the Russians out of the war. This leads me to believe that we were parceling out the war products we were giving them under lend-lease so as to give them good, serviceable planes competitive with their Luftwaffe adversaries, but not our very best cutting edge technology. We wanted them to wear down the Nazis prior to our invasion at D-Day. Just my 2 cents worth. Does this help?

Yes indeed, very insightful. Having the Nazis faced with a two-front war, with a invasion planned from the Atlantic, was good strategy. And having Stalin apparently willing to sacrifice troops and equipment to keep the Nazis occupied on 2 fronts worked to the advantage of the Allied Powers. Makes me also think that the Russians were looking to copy our higher tech aircraft, so keeping those under Allied control was, "smart poker"!! Many thanks-Hansie

 

[pbehn]

He most definitely said the P-39 was his favorite plane (until the P-51B arrived) both in his book and on video, both late in his career. And he also stated that he could not make a P-39 tumble. The video is on youtube.

He may well have, and it is probably true but what other planes did he fly he was at the time just a good trainee pilot. He trained on P39s and then went operational in UK in the P51. To me all he is saying is that he preferred the P39 to his basic trainers, well almost all pilots do.

From Wiki
Soon after entering service, pilots began to report that "during flights of the P-39 in certain maneuvers, it tumbled end over end." Most of these events happened after the aircraft was stalled in a nose high attitude with considerable power applied. Concerned, Bell initiated a test program. Bell pilots made 86 separate efforts to reproduce the reported tumbling characteristics. In no case were they able to tumble the aircraft. In his autobiography veteran test and airshow pilot R.A. "Bob" Hoover provides an account of tumbling a P-39. He goes on to say that in hindsight, he was actually performing a Lomcovak, a now-common airshow maneuver, which he was also able to do in a Curtiss P-40.[36] [N 6] An informal study of the P-39's spinning characteristics was conducted in the NASA Langley Research Center 20-foot Free-Spinning Tunnel during the 1970s. A study of old reports showed that during earlier spin testing in the facility, the aircraft had never tumbled. However, it was noted that all testing had been done with a simulated full ammunition load, which drew the aircraft's center of gravity forward. After finding the original spin test model of the P-39 in storage, the new study first replicated the earlier testing, with consistent results. Then, the model was re-ballasted to simulate a condition of no ammunition load, which moved the aircraft's center of gravity aft. Under these conditions, the model was found to often tumble when thrown into the tunnel.[38]

 

[Hansie Bloeckmann]

can we please, please, please forget this myth. Ford of England had already gone through that before Packard ever got involved.
I would also note that Packard in the 1930s was America's premier auto maker with more prestige than Cadillac. While not quite the craftsmen RR had Packard was turning out a fraction of the cars the mass auto makers were.
View attachment 487101
Such cars were not punched out by untrained labor.

Aaaah yes- Packard- "Ask the man who owns one.. One of their several classic hood ornaments, shaped like a nymph with her left extended forward, a ring clasped in the hand- was nicknamed "The Doughnut Pusher". I have a classic Packard ad poster from early 1929, about 8 months before the October Stock Market crash occurred. I'm not sure, but perhaps the 1920's phaeton Gloria Swanson had in the cult movie "Sunset Blvd." might have been a Packard.. A distant family member was a tool maker in the Packard plant in Detroit during the war years, worked 10 hours/day 7 days a week- Make good $..but never owned a Packard-

 

[michaelmaltby]

"... This leads me to believe that we were parceling out the war products we were giving them under lend-lease so as to give them good, serviceable planes competitive with their Luftwaffe adversaries, but not our very best cutting edge technology"
I am afraid this statement doesn't pass the smell test ... ... the Soviets had a shopping list of things they wanted from the USA and their commissionaires roamed the country ... inspecting factories and mostly getting what they wanted.
What didn't they get? 4-engined bombers ... the USA, GB and Commonwealth needed all such bombers for their 2-Front war ... which the Soviets were NOT fighting.
They received P-47s. They received state-of-the-art radar and communications equipment. They received machine tools. They received trucks, tanks, DUCKs. Food. Food. And more Food. Everything they received was what was being used by the Americans themselves.
And what the Soviets didn't received honorably .. they took by subterfuge ... aka Los Alamos project.
http://lend-lease.airforce.ru/english/documents/index.htm

 

[pbehn]

"... This leads me to believe that we were parceling out the war products we were giving them under lend-lease so as to give them good, serviceable planes competitive with their Luftwaffe adversaries, but not our very best cutting edge technology"
I am afraid this statement doesn't pass the smell test ... ... the Soviets had a shopping list of things they wanted from the USA and their commissionaires roamed the country ... inspecting factories and mostly getting what they wanted.
What didn't they get? 4-engined bombers ... the USA, GB and Commonwealth needed all such bombers for their 2-Front war ... which the Soviets were NOT fighting.
They received P-47s. They received state-of-the-art radar and communications equipment. They received machine tools. They received trucks, tanks, DUCKs. Food. Food. And more Food. Everything they received was what was being used by the Americans themselves.
And what the Soviets didn't received honorably .. they took by subterfuge ... aka Los Alamos project.
http://lend-lease.airforce.ru/english/documents/index.htm

They did receive some four engine bombers, but not part of Lend Lease. They liked them so much they decided to make their own.
Tupolev Tu-4 - Wikipedia

 

[P-39 Expert]

He may well have, and it is probably true but what other planes did he fly he was at the time just a good trainee pilot. He trained on P39s and then went operational in UK in the P51. To me all he is saying is that he preferred the P39 to his basic trainers, well almost all pilots do.

From Wiki
Soon after entering service, pilots began to report that "during flights of the P-39 in certain maneuvers, it tumbled end over end." Most of these events happened after the aircraft was stalled in a nose high attitude with considerable power applied. Concerned, Bell initiated a test program. Bell pilots made 86 separate efforts to reproduce the reported tumbling characteristics. In no case were they able to tumble the aircraft. In his autobiography veteran test and airshow pilot R.A. "Bob" Hoover provides an account of tumbling a P-39. He goes on to say that in hindsight, he was actually performing a Lomcovak, a now-common airshow maneuver, which he was also able to do in a Curtiss P-40.[36] [N 6] An informal study of the P-39's spinning characteristics was conducted in the NASA Langley Research Center 20-foot Free-Spinning Tunnel during the 1970s. A study of old reports showed that during earlier spin testing in the facility, the aircraft had never tumbled. However, it was noted that all testing had been done with a simulated full ammunition load, which drew the aircraft's center of gravity forward. After finding the original spin test model of the P-39 in storage, the new study first replicated the earlier testing, with consistent results. Then, the model was re-ballasted to simulate a condition of no ammunition load, which moved the aircraft's center of gravity aft. Under these conditions, the model was found to often tumble when thrown into the tunnel.[38]

Some pilots said they could make it tumble, some said they could not.

In any case, for the P-39 to tumble the nose ammo had to be exhausted, you had to be in a near vertical position about to stall and you had to pull the stick back even further to even be in position to try and tumble. The expending of the nose ammo had no effect on any other handling issues, no effect at landing speed or near the ground, or in any other flying attitude. A normal loop entered with sufficient speed to complete the loop posed no problem. Just the isolated instance of climbing near vertical and then pulling the stick back. Not a likely maneuver for anyone who has expended their ammunition. Tumbling was largely a non issue with plenty of disagreement on both sides.

Now if you want to experience a "handling problem", just take a P-38 (any of them before the J-25 that came out in June '44 after the Luftwafe had been defeated) and climb it up to 25000'. Then just nose it over a little into a shallow dive. Not a vertical dive, just a little shallow dive. Almost instantly your controls no longer work and your P-38 starts uncontrollably nosing down trying to perform an inverted loop. You are no longer in control of your P-38 and it is screaming toward earth gaining speed and trying to become inverted. Now THAT'S a handling problem.

Or take your new Merlin P-51 that has been on external fuel and try to make any combat maneuver with a full rear fuselage tank. Your P-51 immediately wants to violently swap ends. Cruise along, sight the enemy, drop your tanks and turn to attack and your P-51 wants to fly backwards. That's a handling problem.

Just turn your P-47. Any type of turn. You slowly mush along while your too small wing tries to get enough air to change your direction. You are outturned by even the German fighters who are the least maneuverable. And you have a very lousy rate of climb before you get to 25000'. Most would consider this a handling problem.

While the P-39 had its problems, the other US fighters had their problems too.

 

[P-39 Expert]

"... This leads me to believe that we were parceling out the war products we were giving them under lend-lease so as to give them good, serviceable planes competitive with their Luftwaffe adversaries, but not our very best cutting edge technology"
I am afraid this statement doesn't pass the smell test ... ... the Soviets had a shopping list of things they wanted from the USA and their commissionaires roamed the country ... inspecting factories and mostly getting what they wanted.
What didn't they get? 4-engined bombers ... the USA, GB and Commonwealth needed all such bombers for their 2-Front war ... which the Soviets were NOT fighting.
They received P-47s. They received state-of-the-art radar and communications equipment. They received machine tools. They received trucks, tanks, DUCKs. Food. Food. And more Food. Everything they received was what was being used by the Americans themselves.
And what the Soviets didn't received honorably .. they took by subterfuge ... aka Los Alamos project.
http://lend-lease.airforce.ru/english/documents/index.htm

Stalin also constantly complained that the US and Britain were giving him second line equipment. I don't believe he ever got any P-38s or Merlin P-51s. They did get a few P-47s. But the vast majority were P-39s and P-40s with the Brits throwing in Hurricanes and Spitfires.

 

[P-39 Expert]

Yes indeed, very insightful. Having the Nazis faced with a two-front war, with a invasion planned from the Atlantic, was good strategy. And having Stalin apparently willing to sacrifice troops and equipment to keep the Nazis occupied on 2 fronts worked to the advantage of the Allied Powers. Makes me also think that the Russians were looking to copy our higher tech aircraft, so keeping those under Allied control was, "smart poker"!! Many thanks-Hansie

Be careful, I don't think anyone on this site is permitted to agree with me.

 

[Milosh]

I am sure I read of a P-47 chasing a 109 around the slag heaps during Bodenplatte.

While the P-39 had its problems, the other US fighters had their problems too.

Other US fighters had work arounds or fixes while the P-39 never did.

 

[Milosh]

Stalin did get some P-51s and 4 engine bomber tho not via L-L.

 

[Shortround6]

The big advantage of the Allison mechanical two stage over the turbo is it takes up much less internal volume. In addition to the actual turbo there was the associated internal ducting (14' per engine in the P-38). The exhaust had to be ducted back to the turbo, the compressed turbo air had to be ducted back up to the intercooler (in the wing on F,G and H) then that air had to be ducted to the carburetor. All this ducting had to be properly aligned and sealed for the whole thing to work right.

The Allison mechanical two stage engine simply ducted the ambient air from the external scoop to the carburetor on the first stage and a short duct to take that compressed air to the internal supercharger. The intercooler was not needed except for WEP and that was cooled by the water injection. All was enclosed in the normal engine bay of the P-63 except for the small water tanks in the leading edge.

The turbo developed a little more power at the expense of all that internal room needed. Turbos worked best on multi engined planes because of their greater internal volume. A single engined turbo plane is the P-47 which was huge for a fighter of that day.

The Allison two stage was simpler but then you got less performance.
The -93 was rated at 1325hp for take-off at 54in, and made 1150hp at 22,400ft at 51.5in. Please note that the last is probably as much as the supercharger set will allow.
The -89/91 engines for the P-38 gave 1425hp for take-off at 54in, and were rated at 1425hp at 24,900ft at.......54in. 275hp 2500ft higher. in large part due to the turbos however without the intercoolers the power would have been restricted due to detonation.

ANd compared to the Merlin 61 the V-1710-93 was a bodge. The Merlin 61 was rated at 1390hp at 23,500ft at 60in and the V-1650-3 used in the P-51B was rated at 1330hp at 23,300ft using 66-67in. Lack of intercooler was costing several hundred HP at altitude. Stuffing the -93 Allison into P-51s was NOT going to get you a plane equal to the Merlin Mustang.

Comparing the P-47 is bogus. You are trying to compare a 1150hp engine to a 2000hp engine. The 2000hp engine is obviously larger, heavier, and requires a bigger turbo and a bigger intercooler and larger air ducts than an 1150 hp engine.

Compare P-47 to Hawker Typhoon or Corsair, the only other 2000hp single engine fighters of it's time frame. Engines got much better in just a few years and 2000hp engines got a lot smaller real quick.

Allison was playing catch-up to the Merlin with two stage superchargers. The lack of intercooler hurt high altitude performance. Early P-63s carried 100 gallons of gas and 25 gallons (186.5lbs) of water/alcohol which does nothing for cruise or range. Later P-63s got 126 gallons of fuel.
late P-47s got a 30 gallon water tank to go with their 370 gallons of fuel but then that pushed their WEP to 2560-2600hp at 27,000ft or above.
They weren't using the water to compensate for a lack of intercooling (they were using because air cooled engines don't cool as well as liquid cooled engines)

 

[P-39 Expert]

My head is now hurting. Can someone tell me any area of performance that the latest P-39 was superior to the Spitfire IX or XIV, P-51-B/C, P47 and F4U as of 25 December 1943?

P-39 was not superior to the Spitfire IX or Merlin P-51, I have never stated this. Those had two STAGE engines for high altitude performance.

The F4U and Hellcat had two stage mechanical R-2800s. The P-39N substantially outclimbed both the Corsair and Hellcat. Those planes and the P-47 (those operational in 1943) climbed about the same as the FW190, a little under 3000fpm initially and around 1800fpm at 20000' with a service ceiling of 37000'. The N climbed at near 4000fpm initially and 2650fpm at 20000' with a service ceiling of 38500'. The N was faster under 15000' and a little slower at 25000', 375mph vs about 390mph for the Corsair which was faster than the Hellcat. Hard to believe the N had a higher ceiling than Corsairs and Hellcats.

Since the Hellcat was considered the unquestioned master of the Japanese planes, the P-39N should have been able to handle Zeros like the Hellcat. Zeros were 330-340mph planes, Hellcats and P-39Ns were 40-50mph faster at all altitudes.

 

[Shortround6]

Or take your new Merlin P-51 that has been on external fuel and try to make any combat maneuver with a full rear fuselage tank. Your P-51 immediately wants to violently swap ends. Cruise along, sight the enemy, drop your tanks and turn to attack and your P-51 wants to fly backwards. That's a handling problem.

Just turn your P-47. Any type of turn. You slowly mush along while your too small wing tries to get enough air to change your direction. You are outturned by even the German fighters who are the least maneuverable. And you have a very lousy rate of climb before you get to 25000'. Most would consider this a handling problem.

While the P-39 had its problems, the other US fighters had their problems too.

While the tumbling problem with the P-39 is a gross exaggeration (although it may have been spin prone) both of your examples ar gross exaggertaions which get us nowhere in figuring out what was going on back then.

To get into trouble like you describe for the P-51 you had to disobey the pilots manual instructions. It was done on occasion, however standard procedure was to take-off on one of the wing tanks ( I forget which, it was the vapor return tank) and switch to the rear tank as soon as possible, burn it down to about 25 gallons, switch to the drop tanks and use them. when you punched off the drop tanks no handling problem. In fact you were supposed to land using the fuel from the rear tank with the main wing tanks empty. On long escort missions they may have compromised on how much fuel they left in the rear tank before switching to the drop tanks.

as the P-47, lets see, 300 sq ft wing for a 13,000lb airplane. FW 190A-6, 197 sq ft for a 9100lb airplane, yep P-47s wing was too small?
P-47s were evolving the early ones sure had a poor rate of climb But in less than 6 months over the winter of 1943/44 they got better propellers and two different water injection set ups, the first moved the max manifold pressure from 52in to 56in, the 2nd moved it to 64-65 in. CLimb rate at the lower altitudes increased by as much as 33% at certain altitudes. Not a threat to a Spitfire but some of those poor climbing 190s you talk about were in for some rude shocks.

All aircraft had at least a few problems. The P-39 simply didn't bring enough to the table to warrant continued production or extensive improvement. Too much had to be changed and the layout of the plane made large upgrades problematic. At what point do you simply start over? Like the P-63 and that one missed the boat. Better than the P-39 but the boat had already left the dock.

 

[P-39 Expert]

While the tumbling problem with the P-39 is a gross exaggeration (although it may have been spin prone) both of your examples ar gross exaggertaions which get us nowhere in figuring out what was going on back then.

To get into trouble like you describe for the P-51 you had to disobey the pilots manual instructions. It was done on occasion, however standard procedure was to take-off on one of the wing tanks ( I forget which, it was the vapor return tank) and switch to the rear tank as soon as possible, burn it down to about 25 gallons, switch to the drop tanks and use them. when you punched off the drop tanks no handling problem. In fact you were supposed to land using the fuel from the rear tank with the main wing tanks empty. On long escort missions they may have compromised on how much fuel they left in the rear tank before switching to the drop tanks.

as the P-47, lets see, 300 sq ft wing for a 13,000lb airplane. FW 190A-6, 197 sq ft for a 9100lb airplane, yep P-47s wing was too small?
P-47s were evolving the early ones sure had a poor rate of climb But in less than 6 months over the winter of 1943/44 they got better propellers and two different water injection set ups, the first moved the max manifold pressure from 52in to 56in, the 2nd moved it to 64-65 in. CLimb rate at the lower altitudes increased by as much as 33% at certain altitudes. Not a threat to a Spitfire but some of those poor climbing 190s you talk about were in for some rude shocks.

All aircraft had at least a few problems. The P-39 simply didn't bring enough to the table to warrant continued production or extensive improvement. Too much had to be changed and the layout of the plane made large upgrades problematic. At what point do you simply start over? Like the P-63 and that one missed the boat. Better than the P-39 but the boat had already left the dock.

In order to spin a plane must first stall. According to the training films and other sources the P-39 had excellent stall characteristics with plenty of warning and no wing drop. I wouldn't recommend spinning one, but you had to get into substantial trouble before that happened.

Regarding the fuselage tank, I read a pilot's comments that it was a court martial offense to use the fuselage tank before exhausting the drop tanks. Any usage of the fuselage tank prior to exhausting the drop tanks meant a loss of range if the drop tanks had to be dropped before they were empty. Use your fuselage tank before your drop tanks and you have one third less internal fuel after they are dropped.

Both the FW190 and the P-47 wings were too small. Both were known as sleds and the FW190 had real stall problems and the resulting spin was quite an experience with control reversal.

There were a lot of propeller comparisons in wwiiaircraftperformance for the P-47, but again did any of these props actually get used before 1944? The P-47D-10 test on Oct 11 1943 said it used the STANDARD Curtiss 12'2" propeller that had been used on all the production P-47s to date. One thing that I don't like about wwiiaircraft is all the experimental testing with different propellers and exotic fuels that never got into use before the Luftwaffe was defeated in March 1944. So a lot of information is on that site about planes that never saw the light of day, or if they did it was too late to have a meaningful impact on the war. Oh well.

 

[BiffF15]

Some pilots said they could make it tumble, some said they could not.

In any case, for the P-39 to tumble the nose ammo had to be exhausted, you had to be in a near vertical position about to stall and you had to pull the stick back even further to even be in position to try and tumble. The expending of the nose ammo had no effect on any other handling issues, no effect at landing speed or near the ground, or in any other flying attitude. A normal loop entered with sufficient speed to complete the loop posed no problem. Just the isolated instance of climbing near vertical and then pulling the stick back. Not a likely maneuver for anyone who has expended their ammunition. Tumbling was largely a non issue with plenty of disagreement on both sides.

Now if you want to experience a "handling problem", just take a P-38 (any of them before the J-25 that came out in June '44 after the Luftwafe had been defeated) and climb it up to 25000'. Then just nose it over a little into a shallow dive. Not a vertical dive, just a little shallow dive. Almost instantly your controls no longer work and your P-38 starts uncontrollably nosing down trying to perform an inverted loop. You are no longer in control of your P-38 and it is screaming toward earth gaining speed and trying to become inverted. Now THAT'S a handling problem.

Or take your new Merlin P-51 that has been on external fuel and try to make any combat maneuver with a full rear fuselage tank. Your P-51 immediately wants to violently swap ends. Cruise along, sight the enemy, drop your tanks and turn to attack and your P-51 wants to fly backwards. That's a handling problem.

Just turn your P-47. Any type of turn. You slowly mush along while your too small wing tries to get enough air to change your direction. You are outturned by even the German fighters who are the least maneuverable. And you have a very lousy rate of climb before you get to 25000'. Most would consider this a handling problem.

While the P-39 had its problems, the other US fighters had their problems too.

P-39,

You are correct that pretty much every aircraft had its vices, which remains true to this day (on this I agree). However place yourself in one of the above planes, deep in enemy territory on a long'ish mission. Every one of those examples you gave with the exception of the 38 & 39 things got better as fuel / ammo went down (and with less fuel things got better for those two). However, from my perspective the lower the fuel in my plane the harder I can push it, the more options I have maneuver wise, which oh by the way is the same for my adversary. The P39 vice is particularly critical as turning fights work down in altitude and should the Airacobra "bite" with a tumble you are fighting your plane and the enemy simultaneously for your life. The regular Joe fighter pilot is not going to bury his nose at low altitudes (P38), or mission plan with the odds of engaging soon after takeoff (P51) which will put you in a losing place from the get go.

I have always been a fan of the early war fighters (38, 39 & 40). However, should I be the one flying in combat and the choice was mine I would probably go with what the AAF chose, the Mustang, Thunderbolt in ETO, and or those plus the Lightning in the SWP. Previously pointed is what the AAF chose, and the difficult part for you to perhaps get your arms around seems to be the why. Those guys making those choices were there in the thick of it.

Cheers,
Biff

 

[pbehn]

In order to spin a plane must first stall. According to the training films and other sources the P-39 had excellent stall characteristics with plenty of warning and no wing drop. I wouldn't recommend spinning one, but you had to get into substantial trouble before that happened.

Regarding the fuselage tank, I read a pilot's comments that it was a court martial offense to use the fuselage tank before exhausting the drop tanks. Any usage of the fuselage tank prior to exhausting the drop tanks meant a loss of range if the drop tanks had to be dropped before they were empty. Use your fuselage tank before your drop tanks and you have one third less internal fuel after they are dropped.

Both the FW190 and the P-47 wings were too small. Both were known as sleds and the FW190 had real stall problems and the resulting spin was quite an experience with control reversal.

There were a lot of propeller comparisons in wwiiaircraftperformance for the P-47, but again did any of these props actually get used before 1944? The P-47D-10 test on Oct 11 1943 said it used the STANDARD Curtiss 12'2" propeller that had been used on all the production P-47s to date. One thing that I don't like about wwiiaircraft is all the experimental testing with different propellers and exotic fuels that never got into use before the Luftwaffe was defeated in March 1944. So a lot of information is on that site about planes that never saw the light of day, or if they did it was too late to have a meaningful impact on the war. Oh well.

The rear fuselage tank and 100 gal external tanks were to perform specific missions. The instructions given to the pilot were quite clear and I have read them here many times. I believe what I read because some of the people doing the writing work on these planes and know or knew people who flew the missions.
The effect on the CoG of the rear tank and the necessity to drain, not empty it was researched. To my knowledge it was a wartime special measure, no P51 today is allowed to fly with those fuel loads, the plane was borderline unstable. However with the P39 the reports of tumbling and flat spins were actually not believed by Bell, only when they did tests with no ammunition were they believed. Now this means that the plane had not been fully tested before entering service, having no ammunition is a normal condition on a combat plane.

If the LW was defeated in March 1944 who put the Me262 into service and what use was the P51D?