# P-39 vs P-40



## gjs238 (Jun 18, 2009)

Why did the P-39 perform, or seem to perform, so much more poorly than the P-40 - particularly in the early war years?

Both were V-1710 powered, sans turbocharger with single stage/single speed supercharger.

I know the P-39 had short endurance.
But what else?


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## Colin1 (Jun 18, 2009)

gjs238 said:


> Why did the P-39 perform, or seem to perform, so much more poorly than the P-40 - particularly in the early war years?


I don't think it did
the P-39 didn't get much of a look-in with western air forces but the Soviet Union employed it in numbers and with it Soviet pilots regularly mixed it up with the Luftwaffe. It fell short with later versions of the Bf109 and the arrival of the Fw190 but that was later, rather than earlier in the war. Soviet pilots were impressed with its low-level performance, manoeuvrability, heavy armament and structural strength.

It's also worth noting that of the top 5 Soviet aces, P-39 drivers occupied slots 2, 3 and 4.

It had handling problems, I think spinning was one of them. In its initial configuration, it had the altitude of the P-38 but curiously, Bell thought they could improve the type by shortening the wings, lengthening the fuselage and lowering the canopy profile; this impinged on the available space and supercharging fell back on a single-stage arrangement. This was quite unlike the P-40 which never had the altitude performance from the outset.


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## davebender (Jun 19, 2009)

> It had handling problems, I think spinning was one of them.


Spinning is about the worst possible problem to have when you are flying at low altitude. I suspect some pilots were afraid to fly the P-39 at max ability for fear of a low altitude spin.

Low endurance is a huge problem, as the Luftwaffe discovered during the Battle of Britain.


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## Colin1 (Jun 19, 2009)

davebender said:


> Spinning is about the worst possible problem to have when you are flying at low altitude.
> 
> I suspect some pilots were afraid to fly the P-39 at max ability for fear of a low altitude spin.
> 
> Low endurance is a huge problem, as the Luftwaffe discovered during the Battle of Britain.


Never doubted it for a minute 

The Soviets seemed to get the best out of it

Low endurance was a huge problem for the western Alllies until late 1944 but of course, by then the P-39 had been supplanted by better designs. It was not quite such a problem for the Soviets, who principally used it to:

_Protect ground units from enemy aircraft 
Escort bombers 
Suppress AAA in the area of bombers 
Reconnaissance 
Free hunt 
Attack soft targets (i.e. troops, convoys, supply dumps, railroads, airfields, barges or other small naval craft) 
Protect high-value friendly targets (i.e. bridges, amphibious landing forces, reserves, command and control, major cities, etc)_

rather than long-range escort duties or even just hopping across the Channel. That's not to say that range wasn't an issue, more is clearly better but if the Soviets were doing all of this then they were obviously locating all of their P-39 units just behind the action on the ground and largely negating any endurance issues.


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## gjs238 (Jun 19, 2009)

Endurance:
If I understand correctly, the plane was submitted as a response to Circular Proposal X-609 - didn't that contain any criteria for endurance?

Turbocharger:
Mounting the turbocharger close to the engine, as was done on the P-38 and bombers, makes for a clean, simple and compact package. The P-39 seemed to provide a great opportunity for this.
I always read about how the mid-engine placement was ideal for the nose mounted cannon and a streamlined profile, but I can't help but feel that turbocharger placement was a great beneficiary of this layout.

P-39 vs. P-40 statistics:
Do we know how the P-39 compared to the P-40 statistically?
- Early war years in Pacific theatre.
- In Soviet Union.


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## timshatz (Jun 19, 2009)

Think the Soviets also took some of the armor out as well as dumped a few machine guns. Made it a lighter bird, closer to the original spec.


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## Colin1 (Jun 19, 2009)

gjs238 said:


> Turbocharger:
> Mounting the turbocharger close to the engine, as was done on the P-38 and bombers, makes for a clean, simple and compact package. The P-39 seemed to provide a great opportunity for this.
> I always read about how the mid-engine placement was ideal for the nose mounted cannon and a streamlined profile, but I can't help but feel that turbocharger placement was a great beneficiary of this layout


The problem 
with turbocharger arrangements is the hefty volume of ducting to and from the engine and the double problem is where would you put it all in the P-39? It sat behind the pilot in the P-47 (a substantially bigger bird than the P-39) but with the engine behind the pilot in the P-39, it clearly can't go there; Bell needed to weigh up the pros and cons of their lower-profile canopy vs the choice of single or two-stage supercharging, it might have had a different history altogether with the western Allied airforces.

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## gjs238 (Jun 19, 2009)

Colin1 said:


> The problem
> with turbocharger arrangements is the hefty volume of ducting to and from the engine and the double problem is where would you put it all in the P-39? It sat behind the pilot in the P-47 (a substantially bigger bird than the P-39) but with the engine behind the pilot in the P-39, it clearly can't go there; Bell needed to weigh up the pros and cons of their lower-profile canopy vs the choice of single or two-stage supercharging, it might have had a different history altogether with the western Allied airforces.



The prototype XP-39 flew with the turbocharger and performed well.
The P-38 mounted the turbo behind the engine in the nacelle nicely.
Extensive ducting is not required.


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## Colin1 (Jun 19, 2009)

gjs238 said:


> The prototype XP-39 flew with the turbocharger and performed well.
> The P-38 mounted the turbo behind the engine in the nacelle nicely.
> Extensive ducting is not required.


My apologies
I was under the impression the XP-39 flew with two-stage supercharging


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## Juha (Jun 19, 2009)

IIRC there was capacity promlem in turbocharger production, bombers needed it also. At least part of USAAF hierarcy saw the main function of US fighters as protection of USA beaches against invasition, so low altitude work, so no need to put turbo into all fighters.

Juha

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## gjs238 (Jun 19, 2009)

Juha said:


> IIRC there was capacity promlem in turbocharger production, bombers needed it also. At least part of USAAF hierarcy saw the main function of US fighters as protection of USA beaches against invasition, so low altitude work, so no need to put turbo into all fighters.
> 
> Juha



There were plenty of turbochargers for the P-38 P-47, both of which reached operational status after the P-39.
Decision seemed to be made by NACA for aerodynamic reasons.


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## Juha (Jun 19, 2009)

You might well be right, but the fact that there was plenty of turbos available later doesn't prove in itself that the supply was adequate earlier when the decision was made. But as I wrote, you might well be right.

Juha


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## davebender (Jun 19, 2009)

The P-38 and P-47 cost twice as much as many other fighter aircraft. Which suggests to me that turbochargers and their associated ducting were very expensive. Not even the U.S. can afford to turbocharge the entire fighter force.


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## ssnider (Jun 19, 2009)

I got to talk to a pilot severial years ago who flew both the P39 and P40 in combat. For him the biggest differance was in reliability. He said that the some part of the P39 electical system failed on evey mission, and everything was electic. he said the P40 was ok and dependable. He had also flew P36s before the war and finished the war in a P51, which he considered vastly better then anything else.

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## gjs238 (Jun 19, 2009)

davebender said:


> The P-38 and P-47 cost twice as much as many other fighter aircraft. Which suggests to me that turbochargers and their associated ducting were very expensive. Not even the U.S. can afford to turbocharge the entire fighter force.



Sure didn't stop them from turbocharging the bombers.
I doubt this is why NACA removed the turbo from the XP-39.
And the P-38 needed TWO turbos per plane.


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## Marshall_Stack (Jun 19, 2009)

I have read in Warren Bodie's book on the P-38 that NACA said that the turbo installation had too much of a drag penalty on the P-39 and that is why it was deleted. I have read other accounts that there was a problem with the turbo on the P-39 and they deleted it because of this trouble.


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## Colin1 (Jun 19, 2009)

ssnider said:


> ...the biggest differance was in reliability. He said that the some part of the P-39 electrical system failed on every mission, and everything was electric...


Throughout its service life, many considered the P-39 to be a maintenance nightmare, largely owing to 

not-too-reliable electrical systems
engine-cooling problems
excessive vibration fatigue with the long, geared propeller drive

there were efforts to correct these over the period 1942-44 with mixed results. Alot of the problems could have been nipped in the bud during the design phase but never were.

Lt Winton W 'Bones' Marshall
Las Vegas Army Airfield, Nevada, 1944:

_The P-39 had an electric, motor-driven worm gear to raise and lower the landing gear. In the event of an electrical power failure, you had to make endless rotations by hand, of a landing gear crank, to get the gear down. On one occasion with electrical power failure, I had cranked my gear down but the landing gear would not lock in place. So I held the crank handle with all my might on landing to keep it from collapsing.
As the aircraft slowed, the crank and the landing gear started to unwind. I tried to grab it again with my hand but it was going too fast and hard to catch. As I immediately stopped the P-39 on the runway, the gear crank continued to unwind to within an inch of the propeller hitting the runway. My hand was black and blue for a week._


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## Colin1 (Jun 19, 2009)

gjs238 said:


> I doubt this is why NACA removed the turbo from the XP-39


The XP-39B was flown on 25Nov39 and was the XP-39 prototype rebuilt with considerable modification.
Gone was the 1,150hp V-1710-17(E2) B-5 turbocharged powerplant and in came the 'improved' 1,090hp V-1710-37(E5) unit with single-stage integral mechanical supercharger.
The removal of the turbocharger was recorded as necessary for two reasons, firstly, when the P-39 was being designed, US turbochargers weren't that reliable and secondly, NACA noted that the original Airacobra design had numerous lift and drag problems.
The changes made by NACA were done in stages, most were put in place at Langley Field, Virginia and the wind-tunnel tests determined a need for the improvements that were incorporated into the XP-39B. These included:

streamlining and reducing the size of the wheel doors
lowering and streamlining the canopy
moving the carburettor air scoop from the left side of the cockpit to directly behind the cockpit and 
moving radiators from the fuselage sides to the central wing-root leading edges

along with a slightly altered fin and an all-up weight increased by about 15%

*Top photo: The prototype P-39 (38-326), progenitor of all Airacobras to follow, poses at Wright Field around the time of its 06Apr39 maiden flight. The P-39 had a radiator and oil cooler on its starboard side behind the exhaust outlets and a three-bladed Curtiss-Wright propeller. The details of the cockpit underwent numerous changes from the drawing board to the flight line.*_ via Dave Ostrowski_

*Lower photo: The XP-39B in its initial configuration at the Buffalo plant on 05Dec39.* _Bell via Truman Partridge_


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## Marshall_Stack (Jun 19, 2009)

Colin1 said:


> The XP-39B was flown on 25Nov39 and was the XP-39 prototype rebuilt with considerable modification.
> Gone was the 1,150hp V-1710-17(E2) B-5 turbocharged powerplant and in came the 'improved' 1,090hp V-1710-37(E5) unit with single-stage intregral mechanical supercharger.
> The removal of the turbocharger was recorded as necessary for two reasons, firstly, when the P-39 was being designed, US turbochargers weren't that reliable and secondly, NACA noted that the original Airacobra design had numerous lift and drag problems.
> The changes made by NACA were done in stages, most were put in place at Langley Field, Virginia and the wind-tunnel tests determined a need for the improvements that were incorporated into the XP-39B. These included:
> ...




I'm curious, how did the weight go up after removing the supercharger and putting in a smaller engine? Did the "improved" model include armor and sefl-sealing fuel tanks?


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## VG-33 (Jun 19, 2009)

gjs238 said:


> Why did the P-39 perform, or seem to perform, so much more poorly than the P-40 - particularly in the early war years?
> 
> Both were V-1710 powered, sans turbocharger with single stage/single speed supercharger.
> 
> ...



My advice, read Golodnikov in english at lend lease airforce ru.

Regards

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## Colin1 (Jun 19, 2009)

Marshall_Stack said:


> I'm curious, how did the weight go up after removing the supercharger and putting in a smaller engine? Did the "improved" model include armor and self-sealing fuel tanks?


Even more curiously
it was rolled out with no armament and still didn't have one by Jan40, no mention of where the extra weight was coming from.

As a final note to the wind-tunnel testing carried out by NACA, one NACA official said on satisfactory completion of the tests "We have eliminated a million and one aerodynamic problems by removal of the turbocharger"

... and left it with one big one


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## Marshall_Stack (Jun 19, 2009)

Colin1 said:


> Even more curiously
> 
> As a final note to the wind-tunnel testing carried out by NACA, one NACA official said on satisfactory completion of the tests "We have elmininated a million and one aerodynamic problems by removal of the turbocharger"
> 
> ... and left it with one big one



They should have put that official in a castrated P-39 up in the air with Zeroes over the Solomon Islands.

I have also read that Mr. Bell (Larry?) tried to persuade the USAAF to keep the turbocharger but didn't press the point since his company needed the money. It would have been nice if he continued testing / developing a model with the turbo on his own dime. Easy for me to say of course.


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## Colin1 (Jun 19, 2009)

Marshall_Stack said:


> I have also read that Mr. Bell (Larry?) tried to persuade the USAAF to keep the turbocharger but didn't press the point since his company needed the money. It would have been nice if he continued testing/developing a model with the turbo on his own dime


Larry Bell ran his company a damn sight more conscientiously than Vaughn did Curtiss-Wright but he was nonetheless more bean-counter than engineer.

The P-39 really was a victim of 30s USAAC doctrine, bombers were regarded as the primary force in aviation, modest demands were placed on fighter design; the idea that fighters would routinely partake in high-altitude combat was not envisaged.

It wasn't just Bell, both Curtiss-Wright and Allison were ploughing ahead with their myopic, blinkered vision of what made a great fighter, completely lacking in adequate supercharging and no-one, not in the industry or the military found it remarkable. Allison, though a small company at the time (a division of General Motors) would not have come up with an engine so rigidly constrained by the standardised intregral mechanical power section if they hadn't believed they were on the proper course.

The Army eventually dropped its requirement for the turbocharger and even Bell saw this as a good move, solely for financial reasons; there was no hesitation in deleting the requirement from the planning or development process. The Army's outmoded views on fighter requirements had more or less infected the industry across the board and this would come back to hurt the USAAC in the early years of the war.

It's a great shame because the turbocharged P-39 would have been a match for the A6M and Bf109 at any altitude, in any climate or on any day of the week. Bell, Allison and the USAAC made the P-39 the mediocre fighter that it was but it was no different to events being played out a few hundred miles away where Curtiss-Wright were busy emasculating the P-40.


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## Njaco (Jun 19, 2009)

Could also be that Soviets flew ops at a lower altitude than Western Front pilots and the P-39 handled better at those heights.


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## gjs238 (Jun 19, 2009)

Colin1 said:


> where Curtiss-Wright were busy emasculating the P-40.



How so?


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## gjs238 (Jun 19, 2009)

Colin1 said:


> It's a great shame because the turbocharged P-39 would have been a match for the A6M and Bf109 at any altitude, in any climate or on any day of the week.



Would it really have been?
Is it possible the NACA changes to the XP-39 improved low/medium level performance?
(not making an argument, just a question)


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## gjs238 (Jun 19, 2009)

Colin1 said:


> Bell, Allison and the USAAC made the P-39 the mediocre fighter that it was



Allison?
Was the Allison supercharger design so out of touch with other contemporary designs?

Later on, yes - but in 1939?
How did DB600 and RR Merlin superchargers compare in 1939?


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## Juha (Jun 20, 2009)

Hello Njaco
Normally aircombats over Eastern Front were fought under 5000 meters, most clearly lower.

Juha


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## Juha (Jun 20, 2009)

Marshall_Stack
self-sealing fuel tanks were introduced later, first to have them was P-39D.

Juha


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## Juha (Jun 20, 2009)

Hello
what Colin1 wrote
Quote:"firstly, when the P-39 was being designed, US turbochargers weren't that reliable..."

might well explane why P-38 had turbo but P-39 and P-40 didn't. It would not be surprising if USAAF. while thinking that most of fighter job would be at low and medium level and so no need for turbo to all fighters there might be some need to high altitude capacity, so they decided to keep turbo in one type and because of reliability problems still around put them in twin engined fighter.

Juha


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## gjs238 (Jun 20, 2009)

Juha said:


> It would not be surprising if USAAF. while thinking that most of fighter job would be at low and medium level and so no need for turbo to all fighters there might be some need to high altitude capacity, so they decided to keep turbo in one type and because of reliability problems still around put them in twin engined fighter.



The P-40 was not designed for a turbocharger and never had one to remove.
The XP-39 changes by NACA seem to be limited to aerodynamic streamlining, not other issues.

Turbo equipped planes could be optionally produced sans turbo, such as the P-38's that were sold to Great Britain pre-Pearl Harbor.


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## Juha (Jun 20, 2009)

Hello gjs
Quote:"The P-40 was not designed for a turbocharger and never had one to remove."

I knew that

Juha


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## davebender (Jun 20, 2009)

Heavy bombers had priority for the U.S. Army Air Corps just as they did for the RAF. Look at the cost to develop the B-29. A fraction of that money would have provided every Allison engine with a decent supercharger or turbocharger.


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## gjs238 (Jun 20, 2009)

davebender said:


> Heavy bombers had priority for the U.S. Army Air Corps just as they did for the RAF. Look at the cost to develop the B-29. A fraction of that money would have provided every Allison engine with a decent supercharger or turbocharger.



Academically, that statement is true.
But is that the reason the P-40 didn't have a turbo and the turbo was stripped from the P-39?

I suspect it wasn't an issue of funding or availability, but HOW to make it work.
How would one turbocharge the P-40?
The little I've read indicates that NACA stripped the turbo from the P-39 as one of many aerodynamic streamlining recommendations.


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## claidemore (Jun 20, 2009)

davebender said:


> Heavy bombers had priority for the U.S. Army Air Corps just as they did for the RAF.



But they did not yet see the necessity for escort fighters. Early in the war they (the US) thought the bombers would be able to protect themselves.


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## davebender (Jun 20, 2009)

There you have it. The U.S. Army Air Corps thought their fighter aircraft would be operating at mostly low altitude. So why spend the money putting a decent supercharger / turbocharger on the Allison engine?


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## gjs238 (Jun 20, 2009)

davebender said:


> There you have it. The U.S. Army Air Corps thought their fighter aircraft would be operating at mostly low altitude. So why spend the money putting a decent supercharger / turbocharger on the Allison engine?



Something is wrong with this...

So the Army issued Circular Proposal X-608 for a high-altitude interceptor aircraft having "the tactical mission of interception and attack of hostile aircraft at high altitude."
The result was the P-38 (which required TWO turbochargers.)

The Army also issues Circular Proposal X-609, a similar single-engine proposal.
The result was the P-39.
Both proposals required liquid-cooled Allison V-1710 engines with turbo superchargers.

Then the P-43 was developed, and fielded, with a turbo supercharger.

The P-43 morphed into the P-47, famous for its turbo supercharger.

Yet, the Army decides for reasons speculated in earlier posts to remove the turbo supercharger from the P-39?
I still strongly suspect is was NACA and the reasons were aerodynamic.


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## gjs238 (Jun 20, 2009)

That's right, but they were very keen on *interceptors*.


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## gjs238 (Jun 20, 2009)

gjs238 said:


> Why did the P-39 perform, or seem to perform, so much more poorly than the P-40 - particularly in the early war years?
> 
> Both were V-1710 powered, sans turbocharger with single stage/single speed supercharger.
> 
> ...




Getting back to where this thread started...


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## fastmongrel (Jun 20, 2009)

Did they ever try to fit a Merlin engine into the P39. The low level rated Merlin 24 engine with 1600 hp could have made it into a pretty rapid fighter.


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## claidemore (Jun 21, 2009)

Like VG-33 said, read Golodnikovs interview. Not only is it informative about the P40 and P39, but gives some interesting insight into what performance criteria were actually most important for air combat. 

Conversations with N.Golodnikov

Heres an excerpt pertaining to the P39:


> A. S. Nikilay Gerasimovich, could the Cobra really contend with the Bf-109G and FW-190 in aerial combat?
> 
> N. G. Yes. The Cobra, especially the Q-5, took second place to no one, and even surpassed all the German fighters.
> 
> I flew more than 100 combat sorties in the Cobra, of these 30 in reconnaissance, and fought 17 air combats. The Cobra was not inferior in speed, in acceleration, nor in vertical or horizontal maneuverability. It was a very balanced fighter.



and one pertaining to the P40.



> N. G. I say again, the P-40 significantly outclassed the Hurricane, and it was far and away above the I-16.
> 
> Personally speaking, the P-40 could contend on an equal footing with all the types of Messerschmitts, almost to the end of 1943. If you take into consideration all the tactical and technical characteristics of the P-40, then the Tomahawk was equal to the Bf-109F and the Kittyhawk was slightly better.
> 
> ...



Basically Golodnikov says the P40 was a good fighter, but the P39 was better.


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## Colin1 (Jun 21, 2009)

There seems to be a fair amount of evidence around that the P-39 was a far more respectable fighter than western allied pilots gave it credit for, within a low-level combat environment even its maximum speed was perfectly acceptable, in fact, in some regimes it was faster than the A6M or Bf109 and was more heavily-armed than the P-51.

I think that the key to the P-39's abilities however was its manoeuvrability. An RAF evaluation document from 1941 stated: 

_the Bf109 could not compete with the Airacobra in a turn and even if the Bf109 were behind at the start, the Airacobra should be able to out-manoeuvre and get onto the tail of the Bf109 within two complete turns._

On 12Dec41, Col Claire Chennault's AVG went into combat against the Japanese from Mingaladon in Burma using Curtiss P-40B/C variants. Days later, they moved up to Kunming in China to defend the Burma road. For the next six months they would perform well against the likes of the Ki-44 but at least one historian wondered if they might have fared even better had they been equipped with the Bell fighter instead. Rick Mitchell, author of _Airacobra Advantage_, points out that most aviation experts automatically assume the P-40 to be superior to the P-39. He insists that, on the contrary:

_The truth is that no model of the P-40 during its entire service was ever as fast as the slowest version of the P-39. No P-40 was ever armed with the tremendous firepower or knockout punch carried by every P-39. Too many... make the mistake of comparing the P-39, America's earlier modern fighter plane, with much later WWII fighter designs such as the P-47 and the P-51._

So, although the AVG was largely a success, Mitchell believes that their record against the Japanese would have been even higher with Airacobras.

Anecdotally, the P-39 received a mention in a speech from none other than Churchill himself; speaking of the war build-up he promised that Britain would be getting more Spitfires and Airacobras - a curious choice given that the most numerous fighter in the RAF and an aircraft still very much in production, was at the time the Hawker Hurricane.


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## Colin1 (Jun 21, 2009)

gjs238 said:


> How so?





gjs238 said:


> Would it really have been?
> Is it possible the NACA changes to the XP-39 improved low/medium level performance?
> (not making an argument, just a question)





gjs238 said:


> Allison?
> Was the Allison supercharger design so out of touch with other contemporary designs?
> 
> Later on, yes - but in 1939?


Hi sorry
didn't see these posts
the blame can be placed at the door of both the USAAC and Allison; before 1938, the USAAC was committed to a program of turbocharged powerplants but Allison had committed to a program of integral, mechanical supercharging in order to simplify production. The only way to introduce second-stage supercharging was as a separate, external unit.
Allison joined forces with Curtiss-Wright to persuade the USAAC to accept the V-1710 in this form for the P-40 contract, relegating the Curtiss aircraft to a low-level role even before it had entered service, though this suited the (quickly outmoded) requirements of the time. The integral, mechanical supercharger was not developed any further throughout its service life in the P-40.

Yet when the V-1710 entered service in the P-38 it was equipped with turbochargers.

Your second post, I don't think so, there seems to be enough existing data to support the notion that NACA had indeed found lift and drag issues with the P-39's airframe and any modifications were designed to overcome that. 
The decision to remove the turbocharger seems to have been made without any real controversy; I would guess that the current USAAC thinking of the time that there would be no high-altitude combat between opposing fighters was well embedded enough to negate any panic. Secondly, Bell lauded the financial relief from removing an unfamiliar, unreliable (at the time) unit that was likely to be fraught with expensive developmental problems.

Your third post, similar to an earlier observation you made, I think you have that the wrong way around too; the early V-1710s were hamstrung performance-wise by the management decision to use the integral mechanical power section, it really handicapped the unit development-wise vs the Merlin say. Later versions of the V-1710, the -143/145s, were as good as anything and were used in all versions of the P-82 bar the B (which used Merlins).


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## Colin1 (Jun 21, 2009)

fastmongrel said:


> Did they ever try to fit a Merlin engine into the P39. The low level rated Merlin 24 engine with 1600 hp could have made it into a pretty rapid fighter.



http://www.ww2aircraft.net/forum/aviation/has-merlin-ever-been-put-into-p-39-a-16729.html


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## MikeGazdik (Jun 22, 2009)

An over simplified summation of varous posts if you will:
1) USAAC envisioned their Bomber force not needing escort, hence no "escort fighters" by design.

2) USAAC wanted the high speed high altitude pursuit to intercept enemy bombers attacking the U.S. homeland , which brought the P-38 with turbocharging ONLY to get to bomber altitude.

3) USAAC also believed that the regular pursuits (not the bomber interceptor) would operate at low or medium altitudes and would not need the turbo installation. Hence the P-36 / P-40 designs, and the turbo removed from the P-39 design.

4) Though the USAAC played with other pursuits with turbo installations, mainly Republic P-43 and such, I believe those were nothing more than fleets of working test beds. They didn't really push for a true full scale production pursuit with the turbo installation, until the P-47. Which was at the dawn of , the Battle of Brittain. USAAC by then had much more info coming back from the European conflicts showing they were wrong in the pursuits not needing high altitude abilities. Then it obviously would take a few more years to learn they were wrong in believing their heavy bombers did not need high altitude escort fighters.

5) All that being said, the P-39 is still awesome to my eyes. Nothing looks sexier on the ramp than that slick nosed, tricycle geared beauty with the snappy Allison exhaust blowing out the middle of the fuselage! And seriously, Airacobra! Not a better name for a fighter has been created. (except maybe Spitfire!)


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## michaelmaltby (Jun 22, 2009)

By all accounts, the Soviets preferred the P-39 to the P-40 ... and preferred the P-40 to the Hurricane.

The Airacobra was a slick, well-built fighter with lots of problems ... but unlike the P-40 and Hurricane it had THIS gun. And if you liked to work at close quarters - and the Reds did - the gun was very effective.

MM


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## VG-33 (Jun 23, 2009)

michaelmaltby said:


> By all accounts, the Soviets preferred the P-39 to the P-40 ... and preferred the P-40 to the Hurricane.
> 
> The Airacobra was a slick, well-built fighter with lots of problems ... but unlike the P-40 and Hurricane it had THIS gun. And if you liked to work at close quarters - and the Reds did - the gun was very effective.
> 
> MM



Considering soviet datas, P-39 was about 20 mph faster than P-40, climbed better but turned a little worse.
Obviously it's acceleration was better too, and respunse time to commands, since the engine was close to GC.

As for P-39, soviets reduced the extra large weight of the P-40, but couldn't do nothing with it's extra large size. 

Regards


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## Colin1 (Jun 23, 2009)

MikeGazdik said:


> 3) USAAC also believed that the regular pursuits (not the bomber interceptor) would operate at low or medium altitudes and would not need the turbo installation. Hence the P-36 / P-40 designs, and the turbo removed from the P-39 design


I believe the reason for its removal was:

i. doctrinal with the USAAC
ii. aerodynamic with NACA and
iii. financial with Bell

a collaboration of misguided ideals that relegated the P-39, quite undeservedly, to the second-tier.


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## gjs238 (Jun 23, 2009)

Colin1 said:


> I believe the reason for its removal was:
> 
> i. doctrinal with the USAAC
> ii. aerodynamic with NACA and
> ...



A nice summation of this thread.
Now that we've separated the wheat from the chaff (the turbocharged planes from the non-turbo planes), I'm still interested in why the disparity between the P-39 P-40.

The Americans and British seemingly vilified the plane.
The Soviets seemingly loved it.

Perhaps the P-39 was a tricky bird to fly.
Like the B-26 Marauder, green pilots and those with closed minds didn't fare well in this plane.

Perhaps it was it's short legs.

Perhaps it was just it's unconventional layout.

Oh yeah, and the spinning problem.
But that didn't seem to dampen Soviet enthusiasm.


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## gjs238 (Jun 23, 2009)

Production numbers according to Wikipedia (I know, take it with a grain of salt)

P-39: 9,584
P-63: 3,303
=======
12,887

P-38: 10,037 (thought this number would be lower)
P-40: 13,738 (thought this number would be higher)
P-47: 15,686
P-51: 15,875 (nice, esp considering how "late" this plane got in the program)

For those always arguing in favor of the P-51, it is amazing how many were cranked out for a plane that entered the game late.

But back to the P-39...
The P-39/P-63 family also churned out a decent amount, all of which did not go to the Soviets.
It seems someone was putting them to use.


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## Demetrious (Jun 24, 2009)

I've been waiting for this thread. 

I never thought of the P-39 much till I started playing it in Il-2. It's easy to look at the raw performance stats of a fighter and write it off, but once you use it in a (reasonably accurate) simulator, you start to notice and appreciate features and aspects of the aircraft that are otherwise not mentioned. For instance, it has been said in this thread that the P-39 is 20mph faster then the P-40 (a solid, but not tremendous, advantage,) but while flying the P-39 in that game, having spent the last few weeks in P-40s, I soon developed the impression that the P-39 was a "hot ship." 

As often happens, I look backwards from my simulator experience to real-world information to see why that is, and I realized that the P-39 is a _much_ cleaner ship then any iteration of the P-40. The P-40 has been discussed at length in these past months on this forum, and many times it's overly draggy nature has been commented on. At a glance, one can see that the P-39 doesn't have that problem. The most difficult thing for any simulator to emulate is drag modeling, but even the rudimentary implementation afforded by this simulator shows me that the P-39 spent far more of it's time in it's upper speed ranges, unlike the P-40. The P-39 doesn't accelerate spectacularly, but it's at least decent, unlike the P-40.

The consequences of that, of course, is that the P-39 often has more energy then the P-40 to throw itself into vertical maneuvers. It's also fortunate because the P-39 was often observed to have poor low-speed handling (in contrast to the P-40, which was oft described as having no vices.) It's stall behavior in vertical maneuvers was also distressing, but only if one attempted such manuvering at lower energy states (which was never a good idea in a plane with an unimpressive power/weight ratio anyway.)

However, it could easily turn with a P-40 (the documents on the Mustang II over at WWIIaircraftperformance.net observe that there is "almost no difference between the P-39, P-40, and P-51 in a turn,) and it had a decent roll rate, giving it a net speed/energy/vertical advantage over the P-40, at the cost of some quirky handling, with nearly identical manuverability. 

It's pretty easy to see why the Russians loved the P-39. It was, indeed, a dangerous aircraft.


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## michaelmaltby (Jun 24, 2009)

I keep hoping that a Soviet WW2 veteran will turn up who flew both the P-39 and P-63 in combat. I'd like to learn his views.

" ... It seems someone was putting them to use." Exactly.

MM


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## claidemore (Jun 24, 2009)

michaelmaltby said:


> I keep hoping that a Soviet WW2 veteran will turn up who flew both the P-39 and P-63 in combat. I'd like to learn his views.
> 
> " ... It seems someone was putting them to use." Exactly.
> 
> MM



His views: Conversations with N.Golodnikov
Read Part 3 and Part 4 specifically.


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## michaelmaltby (Jun 24, 2009)

Golodnikov only mentions flying the P-63 after the war. I am more interested in learning if the Soviets broke the terms of LL and flew their P-63's in the air battles against the Germans in the final few months of the war. Under the terms of delivery the P-63's were only to be used in the East against Japan. But that interview with G is a treasure in terms of details.

Thanks

MM


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## VG-33 (Jun 24, 2009)

michaelmaltby said:


> Golodnikov only mentions flying the P-63 after the war. I am more interested in learning if the Soviets broke the terms of LL and flew their P-63's in the air battles against the Germans in the final few months of the war. Under the terms of delivery the P-63's were only to be used in the East against Japan. But that interview with G is a treasure in terms of details.
> 
> Thanks
> 
> MM



Hello,

Soviets *never *flew P-63 against German on front line units*. All planes served in the PVO (anti-aircraft defence) far in the rear. Maybe one air victory or two against Japan, nothing more.

By 1944 soviets standards it was to slow at low altitude (515 km/h), against 567, 583, 612-630 at SL for serial Yak-3, La 5FN, La-7, and much heavier than other soviet frontal fighters. On the other side it's high altitude capabilities were appreciated.

Regards

Vg-33

*Avions magazine, 3-4 years ago....


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## JoeB (Jun 24, 2009)

michaelmaltby said:


> Golodnikov only mentions flying the P-63 after the war. I am more interested in learning if the Soviets broke the terms of LL and flew their P-63's in the air battles against the Germans in the final few months of the war. Under the terms of delivery the P-63's were only to be used in the East against Japan.


The Soviets used a few P-63's in action in Germany, by 67th GIAP, according to "Red Stars Vol 4" by Geust and Petrov. Also a number of other early units that received them were air defense (PVO) units in the Moscow district, some of those units were later used in the August campaign against Japan along with VVS (and Fleet Air Arm) units. What source says the Soviets were only supposed to use P-63's in the Far East under LL? That seems a little odd given the general situation where the Soviets, while they eventually took advantage of joining the war against Japan (to help the Chinese Communists, establish a friendly regime in NK, etc) at least played the part of if being something of a favor they were doing for the Western Allies.

Joe


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## FLYBOYJ (Jun 24, 2009)

_"As mentioned above, most P-63s were delivered to the Soviet Union via Alaska/Siberia as soon as they had left the factory. One of the routes used led from Niagara Falls to Selfridge Field (Michigan) and on to Truax Field near Madison (Wisconsin). There the Bell fighters were picked up by (mostly) female Russian pilots who flew them via Anchorage (Alaska) to the Soviet Union. Another route went from Great Falls (Montana) to Fairbanks (Alaska) and on to Siberia. One source states that there were 2,397 P-63As and Cs sent to the USSR, of which only 21 were lost en route. Another source records 2,456, of which 2,421 reached their destination. *Deliveries commenced in September 1944 and until May 1945 only 51 P-63As had been received by the Soviet Union. They were assigned to PVO units. This makes any significant use against German tanks or aircraft very unlikely. So the often read statements about the successful Soviet use of the P-63 against German armor seem to have been "extrapolated" from the P-39 Airacobra. *

Re-equipment of Soviet Air Force units with the Kingcobra continued after the end of the war in Europe. The type was used in combat against Japan at the Far East and Trans-Baikal Fronts. The 12th Air Army of the latter Front had its 245th (940th and 781th IAPs) and 190th (17th and 21 IAPs) IADs equipped with Kingcobras. On August 15, 1945 Captain Vyacheslav Sirotin of the 17th IAP, a 21-victory ace and Hero of the Soviet Union, scored the only aerial victory of the P-63 Kingcobra when he shot down a Japanese Ki-27 or Ki-43. Other Soviet P-63-equipped units in the Far East in the summer of 1945 were the Kamtschatka-based 128th SAD (888th and 410th IAPs - the latter having been equipped with Il-2s before as the 410th ShAP) and parts of the 7th IAD of the Pacific Ocean Fleet. In July 1945 the 128th SAD supported the Soviet landings on Shimushu (Kuriles). Soviet Kingcobras normally had their underwing gun gondolas removed. 

After the war re-equipment of new units with the P-63 continued at an accelerated pace. These included the 5th GvIAD in the Baltic District, the 269th IAD in Armenia, the 6th GvIAD in the Ukraine and the 1st GvIAD at Neuhausen in Germany. There were also P-63-equipped units based in Austria and China. About 25 aircraft seem to have been converted into P-63U two-seat trainers in the USSR at that time. The 307th and 308th IAPs in the Kuriles flew the P-63 until as late as 1951. Due to its post-war use in Russia the P-63 even received a NATO code name: "Fred". One of the last incidents involving Soviet P-63s happened in 1952 when USAF jets mistakenly strafed the Soviet airfield of Sukhaya Rechka outside Vladivostok and destroyed 8 (albeit already de-commissioned) P-63s."_

P-63 Kingcobra by Bell


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## Soundbreaker Welch? (Jun 24, 2009)

I didn't realize the P-63 was almost an unused fighter of WWII. I thought the Reds killed a few Germans with it. The P-63 did have good manuverability, but it was too little to late I guess.

I think like Mike said the P-38 was the main fighter the US was planning to use in shooting down attacking bombers, thus the only one allowed to have a supercharger. Sadly for the P-38, it's high altitude performance was still not steller, even with the supercharger. But it was a better energy fighter than the P-39.


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## MikeGazdik (Jun 24, 2009)

Be careful with the term Supercharger. It is an often ( at least in many of the older books ) used but incorrect term applied to WWII fighter engines. Maybe because I am a gearhead, but it matters greatly. The P-38 was Turbocharged. All Allison engines have an intregal single stage Supercharger. So the most correct word to use on the P-38 is actually Turbo-Supercharged. You can look up the technical aspects of each on your own, don't want to get too long winded and sound like a know it all. So in reality, the P-40 and P-39 were Supercharged.


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## gjs238 (Jun 24, 2009)

Soundbreaker Welch? said:


> I think like Mike said the P-38 was the main fighter the US was planning to use in shooting down attacking bombers, thus the only one allowed to have a supercharger.



I would much prefer to see a scan of original documentation stating this policy. Otherwise this is speculation.


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## MikeGazdik (Jun 24, 2009)

gjs238 said:


> I would much prefer to see a scan of original documentation stating this policy. Otherwise this is speculation.



Well, I have read this in many articles, books, etc. Not one in particular to scan. Any reading on the development of the P-38 will point out that it was in fact first developed for bomber interception, and very small production numbers to boot. This caused the Lightning to being almost handmade and very costly. Once the Air Corps wanted thousands, Lockheed had to retool and do a redesign to enable the plane to be more easily made on a production line. This is also one of the delays of its arrival to the inventory.

During about this same time, the P-39 and P-40 were either in use or being put into use. I have also read that these aircraft were intended for mid to low altitude deployment, thus no emphasis on turbocharging the aircraft, by both the manufacturers and the Air Corps. 

I don't think there is too much speculation.


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## FLYBOYJ (Jun 24, 2009)

_"The Lockheed P-38 was designed in response to a 1937 US Army Air Corps (USAAC) specification designated "Project X608" for a fast high-altitude twin-engine interceptor, capable of 580 KPH at an altitude of 6,100 meters (360 MPH at 20,000 feet). Five companies -- Consolidated, Curtiss, Douglas, Lockheed, and Vultee submitted proposals.

The Lockheed team was under the direction of Clarence "Kelly" Johnson, who would eventually design a string of famous aircraft up to the SR-71 Blackbird Mach 3 spy plane. Johnson's initial concepts for the new fighter covered a range of configurations, but the Lockheed team finally decided on a scheme with twin booms to accommodate the engines, and with the pilot and armament in a central nacelle. The aircraft was designated the "Lockheed Model 22". The engines were to be supercharged 12-cylinder, vee-inline, water-cooled Allison V-1710 engines. 

*When Johnson selected the Allison, it had not been rated at even 746 kW (1,000 HP), but it was really the only large inline engine available in the US at the time.* The propellers would rotate in opposite directions to eliminate the effect of torque. The General Electric B-1 superchargers were positioned in the booms, behind the engines. Armament was to consist of four machine guns in the nose of the nacelle, clustered around a cannon. The design featured tricycle landing gear, making the aircraft one of the first with such a feature." _

The Lockheed P-38 Lightning


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## michaelmaltby (Jun 25, 2009)

VG-33 check out the attached link for source of "LL agreement not to use P-63against Germany in the West":

Bell P-63 Kingcobra - History, Specifications and Pictures - World Military Aircraft


MM


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## michaelmaltby (Jun 25, 2009)

And this on Operation August Storm (1945):

Soviet air force support of the Kuriles invasion [3] 

The Soviet air cover and support for the Shimushu landings were provided by the 128 SAD, their 888 IAP had the P-63 Kingcobra, which they had received only in August 1945, before that they remained the last active Soviet fighter regiment with the I-16. The 410 ShAP, also of the same division also had converted to the P-63, in their case from the Il-2 (It is uncertain but possible that they may have been redesignated as 410 IAP.). The third regiment in the division flew a mixture of A-20 and SB bombers, and a few PV-1s which had been interned prior to August 1945. 
The naval torpedo bomber unit was the 2 MTAD (division), consisting of the 4 MTAP (Il-4 DB-3), 49 MTAP (Il-4, A-20G, A-20H), 52 MTAP (DB-3). 

MM


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## VG-33 (Jun 25, 2009)

michaelmaltby said:


> VG-33 check out the attached link for source of "LL agreement not to use P-63against Germany in the West":
> 
> Bell P-63 Kingcobra - History, Specifications and Pictures - World Military Aircraft
> 
> ...



A kind of bullshit i think, your link. Never heard about LL agreement, Kochetov and Suprun went in feb 44 in USA for testing Kingcobras, first one delivered in june 44 via ALSIB. They had twisted one plane (high G) and broke another one during spin trials. Asked for structural enforcements. Both LII and NII tested kingcobras (in SU) from late 1944 to march 1945. In april 45 the comission allowed the use of that plane in VVS units. (That mean no operationnal use before, even in rear training units) The first regiment to be equipped with that plane was the 28th IAP from the Moscow PVO. Followed by 17e and 821e IAP in august. On may the 1st, all PVO units had 51 P-63 on their own. 
No King in frontline units, except 2 or 3 ones, somewhere, sometimes, for operationnal study maybe.

From Viktor Koulikov, P-39 and P-63 in USSR, Avions N°90, Sept 2000.

Regards


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## michaelmaltby (Jun 25, 2009)

VG:33 - " ... Viktor Koulikov, P-39 and P-63 in USSR, Avions N°90, Sept 2000.... "

A link would be nice.

Bullshit or not - the idea that several pairs of P-63's were put in operation in the Baltic region in 1945 (Kronigsnerg/Danzig ??) seems totally realistic. 

MM


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## michaelmaltby (Jun 25, 2009)

VG:33:
" ...By a 1943 agreement, P-63s were disallowed for Soviet use against Germany and were supposed to be concentrated in the Soviet Far East for an eventual attack on Japan. However, there are many unconfirmed reports from both the Soviet and German side that P-63s did indeed see service against the Luftwaffe. Most notably, one of Pokryshkin's pilots reports in his memoirs published in the 1990s that the entire 4th GvIAP was secretly converted to P-63s in 1944, while officially still flying P-39s. One account states they were in action at Königsberg, in Poland and in the final assault on Berlin. There are German reports of P-63s shot down by both fighters and flak. Nevertheless, all Soviet records show nothing but P-39s used against Germany.

Believable .. or fantasy like the 777 Squadron ..?

MM


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## TenGunTerror (Jun 25, 2009)

The P-39 could outmaneuver Bf-109's in tests all the time...until they added the monster 37mm and the other machine guns. They both performed their best at low altitudes but the cumbersome weapons on the P-39 hampered it's ability. The P-39 was much more rugged against gunfire though...


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## FLYBOYJ (Jun 25, 2009)

TenGunTerror said:


> The P-39 could outmaneuver Bf-109's in tests all the time


Care to share those tests? And what model -109s were used?


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## claidemore (Jun 25, 2009)

Here are some questions.

Why would there be an agreement disallowing the P63 for use against Germany? 

Were there any other such agreements regarding any other lend lease material?

What was to be gained by the Soviets sneaking a few P63s into service against the Luftwaffe where they already had overwhelming numerical superiority? It's not like the P63 was a world beater performance wise. 

Why does this document: http://lend-lease.airforce.ru/documents/files/Part_7_section_1.pdf
not list any P63s delivered through lend-lease. Where they actual purchases, rather than lend lease?

Why do so many articles claim the Soviets downplayed the contribution of lend lease aircraft (when they are taking about the P63), yet everyone knows the Soviets gave plenty of praise to the P39 _Kobra_? Cold War era, sure, but now? 

And here's something the aeronauticaly inclinded might find interesting. ClMax figures for the P39D.


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## Juha (Jun 26, 2009)

hello Flyboyj
you can find test results from here http://www.ww2aircraft.net/forum/aviation/soviet-turning-time-tests-comments-please-19130.html
on the first page are the test results with my comments with info on Finnish tests, there are two of them, lower is an updated version. I'll post a still more updated version soon with at least Polikarpov's bi-plane info added, that info is from VG-33's post in the thread.

Altitude 1000m, if 2 times they are left/right turn times.
Tested 109 types, F-4, this seems to have had some problems, at least its top speed was a on low side.
G-2 and G-2/R6, both seemed to have been in good condition. Soviet also tested at least some 109Es

Juha


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## FLYBOYJ (Jun 26, 2009)

Juha said:


> hello Flyboyj
> you can find test results from here http://www.ww2aircraft.net/forum/aviation/soviet-turning-time-tests-comments-please-19130.html
> on the first page are the test results with my comments with info on Finnish tests, there are two of them, lower is an updated version. I'll post a still more updated version soon with at least Polikarpov's bi-plane info added, that info is from VG-33's post in the thread.
> 
> ...



Juda;

Those were turn test and I remember seeing them, thanks for posting. Our friend's statement "The P-39 could outmaneuver Bf-109's in tests all the time" leave some very subjective questions and arguments. In actuality I think its make by someone who plays a lot of IL-2 rather than researching actual performance data.


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## Juha (Jun 26, 2009)

Hello Flyboyj
sorry, my bad. In a hurry I added in my mind the words “on horizontal plane” in the claim “The P-39 could outmaneuver Bf-109's in tests all the time”.
In vertical maneuvers, which IMHO were more important than horizontal maneuvers in air combat, 109 was better than contemporary P-39 version.

Juha


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## VG-33 (Jun 26, 2009)

FLYBOYJ said:


> Care to share those tests? And what model -109s were used?



Look here, 

http://fh-badger.narod.ru/077.htm

Regards


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## VG-33 (Jun 26, 2009)

claidemore said:


> Why does this document: http://lend-lease.airforce.ru/documents/files/Part_7_section_1.pdf
> not list any P63s delivered through lend-lease. Where they actual purchases, rather than lend lease?


Maybe in some appendices. Since this is not the deliveries list, just the agreement act.





> And here's something the aeronauticaly inclinded might find interesting. ClMax figures for the P39D.



Very informative thank you, even high Cl values seemed to be obtained in kind of dynamic way. They are far higher than those obtained by the NII-VVS for the Me-109E-3. 

This might explain a lot of things.

VG-33


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## Demetrious (Jun 26, 2009)

claidemore said:


> Why do so many articles claim the Soviets downplayed the contribution of lend lease aircraft (when they are taking about the P63), yet everyone knows the Soviets gave plenty of praise to the P39 _Kobra_? Cold War era, sure, but now?



What they were downplaying, as far as I understand, was the quantity of the aid, not the quality of the planes received. Their Heroes Of The Great Patriotic War could praise the P-39 as much as they wanted, as long as the Party made it clear that those handfuls of planes were drops in the bucket compared to Soviet aircraft production.


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## Juha (Jun 26, 2009)

Hello Demetrious
I'm not sure, because what you wrote mean that Communist Party of SU was ready to accept that gready capitalists with they lackeys could produce as good products as the First Socialist State in history in spite of the guiding hand of its never erring Politbyro directing its glorious scientists and in spite of all the resources its beloved leader and always efficient peoples had directed to aerodynamic research institutes.

Juha

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## michaelmaltby (Jun 29, 2009)

Claidemore - you've asked three good questions.

I've been thinking about the "Agreement of 1943" re P-63 use by the Soviets. It may well have been an agreement about aircraft delivery -- after all - the Bell plant started P-63 deliveries in late 1943. Until then, more P-39's had been delivered in crates via sea to Iran, assembled there and delivered to the front - than had been flow in via Alaska. Virtually all P-63's were flown - which makes sense if they were for use in the Eastern Campaign (August Storm).

My previous post (#64) quotes a reference to a participating unit in August Storm re-equipping from I-16's to P-63's in August 1945. If this is indeed true (VG 33 why don't you confirm or disprove) the unit would have had no time whatsoever before taking the P-63 operational.

BUT - it suggests that the Soviets didn't see the P-63 as a replacement for the P-39 units but rather as an upgrade for air units operating obsolete or less competitive machines (such as the I-16).

Having a few seasoned P-39 pilots evaluate the P-63 in combat in the west would make a lot of sense - new laminar flow wing, new C of G with the 37 mm canon shifted. etc. etc.

Why there is no mention of P-63's in L.L. documents? -- I can't fathom. Are there other examples of controls on L.L. aircraft -- the Russians wanted the B-17 and the answer was no -- they wanted the B-26 and the answer was no. (We know how they got the B-17 technology and the B-29 anyway)

But, all in all, I don't think there is anything conspiratorial about P-63 delivery and use - just the Soviets staging material into East in preparation for a HUGE, HUGE OFFENSIVE. Which the Soviet Command pulled off on schedule - three months to the day after V.E. Day - per their Yalta commitment.

Unlike the western allies - who had plans to transfer resources to the Pacific for the final fight - the Soviets had the resources to mount August Storm without transferring a single plane.tank or soldier out of Europe.

All in all quite a feat and little appreciated in the west.

MM
Toronto


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## michaelmaltby (Jun 29, 2009)

Further to the above: [From www.lendlease.ru]

"... American Lend-lease to the Soviet Union can be divided into the following phases:

- "pre Lend-lease" 22 June 1941 to 30 September 1941
- first protocol period from 1 October 1941 to 30 June 1942 (signed 1 October 1941)
- second protocol period from 1 July 1942 to 30 June 1943 (signed 6 October 1942)
- third protocol period from 1 July 1943 to 30 June 1944 (signed 19 October 1943)

- fourth protocol period from 1 July 1944, (signed 17 April 1945), formally ended 12 May 1945 but deliveries continued for the duration of the war with Japan (which the Soviet Union entered only 8 August 1945) under the "Milepost" agreement until 2 September 1945 when Japan capitulated. 20 September 1945 all Lend-Lease to Russia was terminated..."

MM


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## claidemore (Jun 30, 2009)

MM:
What it looks like to me, just a theory, was that there was no stipulation to _'not' _use the P63 against Germany, just an _understanding _that the P63's would be used to build up for the operation against Japan. 
This makes sense, as there was no urgent need for another new fighter design to use against the Luftwaffe, and no reason for the Americans to stipulate that it not be used there.


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## claidemore (Jun 30, 2009)

It's interesting that the Free French were delivered P63s in 1945, and they would definately have been earmarked for use against Germany.


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## VG-33 (Jul 1, 2009)

michaelmaltby said:


> VG:33 - " ... Viktor Koulikov, P-39 and P-63 in USSR, Avions N°90, Sept 2000.... "
> 
> A link would be nice.
> 
> ...



Unfortunately, only in russian (maybe with google translater...)

P-63 ????????? ? ????????? ?????

regards

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## michaelmaltby (Jul 1, 2009)

Thank you VG-33. 

MM


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## Tzaw1 (Jul 1, 2009)

Very rough translation, but sense is such:

At 1 May in PVO regiments are 51 P-63s. 
At first Kingkobras received 28th rgt PVO near Moscow.
At August 17th and 821st regiments PVO received 10 planes each.
Autumn 1944 (it seems a mistake, probably 1945) a few planes received 39 IAP in Malino (near Moscow).

Summer VVS started rearmament. Priority had Air Forces at Far East.
They altered the route ALSIB, form Markovo to Petropavlovsk-Kamchatsky, and from Krasnoyarsk route to led off through Chita to Ukkurey (Ukkurey - Wikipedia, the free encyclopedia) for rearmament of 12th Air Force.
By first, apparently, P-63 equipped 190th division of the Major General V.V. Fokin, which was relocated in Transbaykal in June 1945 Since June 24 it began to obtain "Kingcobras" and by August 2 finished retraining. During the combat operations in Manchuria it flew from two airfields - "Ural” and "Leningrad under city Choibalsan in the Mongolia. After war this division a certain time stood under Ulan-Ude. 
There, in the 12th air force at the Transbaikal Front fighted the 245th division, in composition of which were two regiments (940th and 781st), that flew on P-63. In July-August the first of "Kingcobras" they entered in 128th the mixed division, which was being based himself on Kamchatka. P-63 arrived into the 9th and 10th air forces too. For them they lenghten route to Khabarovsk. Here at the beginning military operations it was saved by 97 P-63, which did not have time to give on the regiments.

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## michaelmaltby (Jul 1, 2009)

Thanks Tzaw1

MM


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## Tzaw1 (Jul 1, 2009)

Next fragment:

At this time first P-63 entered into the 7th fighter division VVS of Pacific Ocean fleet. By August 9, when started war with Japan, division had 10 "Kingcobras". About twenty arrived already in the course of military operations, until August 31. They assumed no participation in the operations against the Japanese.


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## Colin1 (Jul 1, 2009)

Tzaw1 said:


> At this time first P-63 entered into the 7th fighter division VVS of Pacific Ocean fleet. By August 9, when started war with Japan, division had 10 "Kingcobras". About twenty arrived already in the course of military operations, until August 31. They assumed no participation in the operations against the Japanese.


What year was this?
I have a record of one Kingcobra being destroyed by the Japanese among 62 (if I recall) of all Soviet types destroyed, at the end of hostilities when the Soviets exploited Japan's exhaustion at the close of WWII to take Sakhalin.


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## claidemore (Jul 1, 2009)

VG-33 said:


> Unfortunately, only in russian (maybe with google translater...)
> 
> P-63 ????????? ? ????????? ?????
> 
> regards



With Babelfish translator:

Translation result for http://www.airpages.ru/uk/p63_2.shtml

Tzaw1 does it better!


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## Tzaw1 (Jul 1, 2009)

Colin1 said:


> What year was this?


1945, of course.

To be continued


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## michaelmaltby (Jul 1, 2009)

Now we are getting somewhere with this P-63 puzzle.

Back at #64 of this thread I posted this:

"The Soviet air cover and support for the Shimushu landings were provided by the 128 SAD, their 888 IAP had the P-63 Kingcobra, which they had received only in August 1945, before that they remained the last active Soviet fighter regiment with the I-16."

The recent translated material seems to mesh with this timeline. August Storm was obviously well-and-long thought out by the General Staff -- executed flawlessly.

But I am struck by the LATE DATE conversion of the last I-16 unit to P-63's as part of the August Storm build up. What that tells me is the QUALITY of fighters that the Soviets could get away with in the Far East from 1941 to '45. Much the same as the USAAF using P-39's in the Panama Canal Zone  

MM


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## Tzaw1 (Jul 2, 2009)

michaelmaltby said:


> Why there is no mention of P-63's in L.L. documents?


P-63 is mentioned on page 7 of this document:
The National Archives | DocumentsOnline | Image Details


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## claidemore (Jul 2, 2009)

Have been reading WARPLANES TO ALASKA by Blake W. Smith and found a couple interesting things. It was a Soviet, General L.G. Rudenko, who requested that all aircraft deliveries of the 4th Protocol of Lend-Lease (which included all P63s), be done by the Alaska-Siberia route, rather than through Iran. Had the Soviets wished to use P63s against Germany, it would have been much simpler to bring them in through Iran. 
Also, a quote from page 197: 


> Aircraft production in the Soviet Ujnion had long since rebounded from th devastating losses suffered in the opening months of the war. Soviet aircraft factories were now in high gear turning out 42,000 airplanes of all types in 1944: a production rate that was fully capable of meeting at least the fighter requirements of the Red Air Force. Even so, the SPC requested continued fighter plane deliveries aimed at rebuilding and reequipping depleted fighter units in the Soviet Far East in anticipation of war against Japan. The majority of P-63 Kingcobras were *diverted *to this region.


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## michaelmaltby (Jul 2, 2009)

Good catch, Claidemore

MM


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## Shortround6 (Jul 3, 2009)

Going by "Vee's for Victory" by Daniel Whitney there were several reasons for deleting the Turbo from the P-39. Not the least of which seems to be that with the original installation the Airplane couldn't come close to the performance estimites or guarantees. Bell was off by about 10% on the weight of the UNARMED plane and off by at least that much in the speed. The intercooler installation seems to have been really bad. It not only had high drag but didn't work very well. In the interest of light weight it had been kept small but the result was that it didn't cool the intake charge very well. While most American intercoolers tried to remove 50% of the heat of compression between the two stages the XP-39 was only managing about 25% during high speed flight and 12% during climb. This ment much more danger of detonation and ment that full power or boost could not be used thus limiting performance of the aircraft. NACA estimated after installing the XP-39 in their full sized windtunnel that a single stage "altitude rated" engine would provide about 30mph more speed than the turbo engine up to about 13-14,000ft. This is after NACA did a clean-up that added 40+mph to the speed of the plane. the Turbo version wasn't expected to show ANY advantage in speed until over 19,000ft had been reached. And it was still about 10mph below the Guarantee speed. Once the requirement changed from 400mph at 20,000ft to 400mph at 15,000 the turbo was really out of the running. The small size of the P-39 ment that installing a larger intercooler setup was almost out of the question.
Please remember that the Early P-38s used the leading edges of the outer wings as inter-coolers and that some models of the P-38 had difficulty in using full power because while these leading edge intercoolers worked well enough with 1150HP engines they were not big enough to handle the airflow of 1300-1425HP engines.

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## fibus (Jul 4, 2009)

Yeager said he could beat anybody in a P 39 at 100 feet. But no one wanted to fight at that altitude.

winkle brown flew both the F 4f and the hurricane.
How did they compare?


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## gjs238 (Jul 6, 2009)

Shortround6 said:


> Going by "Vee's for Victory" by Daniel Whitney there were several reasons for deleting the Turbo from the P-39. Not the least of which seems to be that with the original installation the Airplane couldn't come close to the performance estimites or guarantees. Bell was off by about 10% on the weight of the UNARMED plane and off by at least that much in the speed. The intercooler installation seems to have been really bad. It not only had high drag but didn't work very well. In the interest of light weight it had been kept small but the result was that it didn't cool the intake charge very well. While most American intercoolers tried to remove 50% of the heat of compression between the two stages the XP-39 was only managing about 25% during high speed flight and 12% during climb. This ment much more danger of detonation and ment that full power or boost could not be used thus limiting performance of the aircraft. NACA estimated after installing the XP-39 in their full sized windtunnel that a single stage "altitude rated" engine would provide about 30mph more speed than the turbo engine up to about 13-14,000ft. This is after NACA did a clean-up that added 40+mph to the speed of the plane. the Turbo version wasn't expected to show ANY advantage in speed until over 19,000ft had been reached. And it was still about 10mph below the Guarantee speed. Once the requirement changed from 400mph at 20,000ft to 400mph at 15,000 the turbo was really out of the running. The small size of the P-39 ment that installing a larger intercooler setup was almost out of the question.
> Please remember that the Early P-38s used the leading edges of the outer wings as inter-coolers and that some models of the P-38 had difficulty in using full power because while these leading edge intercoolers worked well enough with 1150HP engines they were not big enough to handle the airflow of 1300-1425HP engines.



Excellent post - thank you.
This helps clear up lingering questions, and dispel much hearsay, about why the turbo was removed from the P-39.

Any insights on why, after these changes were made and the plane fielded, the P-39 was so hated by the Americans but loved by the Soviets?

As this post started, the P-39 P-40 both had single-stage supercharged Allison V-1710's.
Did the P-39 really underperform compared to the P-39?


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## gjs238 (May 25, 2011)

According to Wikipedia (take with a grain of salt)

P-39Q
empty weight 5,347 lbs
loaded weight 7,379 lbs
max takeoff weight 8,400 lbs

P-40E
empty weight 6,352 lbs
loaded weight 8,280 lbs
max takeoff weight 8,810 lbs

If they had same or similar engines, then it seems the P-39 should perform well.


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## tomo pauk (May 25, 2011)

gjs238 said:


> ...
> Any insights on why, after these changes were made and the plane fielded, the P-39 was so hated by the Americans but loved by the Soviets?



P-39 was the perhaps the fastest VVS airplane from 1942-44, featuring a good punch, dependable radio, final finish was much better that of Soviet planes, it's combat range was comparable with other planes. So they have had reasons to love it 
USAAC was fighting on greater ranges, and it was encountering JAAF/IJN bombers in high altitudes, and P-39 was hardly an answer for such tasks.



> As this post started, the P-39 P-40 both had single-stage supercharged Allison V-1710's.
> Did the P-39 really underperform compared to the P-39?



P-39 was batter than P-39 
Jokes aside, P-39 provided slightly better performance figures than P-40 with similar engine.


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## P-39 Expert (Apr 23, 2018)

Just a few comments on this excellent thread.

Turbo was deleted from the P-39 in order to get it into production faster. Contemporary P-38 did not enter combat until Dec '42. P-39D was in production in late '41. Notwithstanding, the turbo instal in the P-39 would never work dependably, radiator ducts (coolant, oil and intercooler) were not adjustable meaning too much air at low power and not enough at high power. Also Allison promised more HP was coming with higher supercharger ratios or a mechanical second stage so turbo was deleted.

When comparing the P-39 and P-40 please remember the P-40 was substantially heavier (7650 vs 8400) so with the same engine and propeller the P-39 was faster and much better climb/ceiling. No way out of it.

Russian P-39s performed better because they were lighter than western P-39s because they deleted the 4x.30caliber MGs in the wings and the IFF radio. They thought the light .30caliber MGs were worthless and plenty firepower was left with the 37mm cannon and 2x.50caliber MGs. Saved about 300# (200# for .30caliberMGs and 100# for IFF radio). Russians lightened the P-40 also by deleting 2 of the 6 .50caliber MGs.

Eastern front was fought at lower altitudes than western front (no turbocharged B-17s and B-24s) but that does not explain the P-39s success in that theater. P-39N/Q was competitive with the Luftwaffe at all altitudes or they could not have had the success they had. Altitude was everything in WWII, without it you were a dead duck.

A chart from wwiiaircraftperformance showing speeds for P-39N and P-40N is attached for reference.

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## P-39 Expert (Apr 23, 2018)

P-39 Expert said:


> Just a few comments on this excellent thread.
> 
> Turbo was deleted from the P-39 in order to get it into production faster. Contemporary P-38 did not enter combat until Dec '42. P-39D was in production in late '41. Notwithstanding, the turbo instal in the P-39 would never work dependably, radiator ducts (coolant, oil and intercooler) were not adjustable meaning too much air at low power and not enough at high power. Also Allison promised more HP was coming with higher supercharger ratios or a mechanical second stage so turbo was deleted.
> 
> ...


The P-40N in the above graph is the untralight early N that only weighed 7600# and reverted to the normal weight for production. So production P-40Ns would be slower than this one.


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## Csch605 (Nov 26, 2018)

gjs238 said:


> Endurance:
> If I understand correctly, the plane was submitted as a response to Circular Proposal X-609 - didn't that contain any criteria for endurance?
> 
> Turbocharger:
> ...


The turbochargers were given to the P38 due to politics and scarcity of turbochargers. tHe P38 was a fine plane but was used 2 turbochargers two motors and over twice the materials. The P40 could have used the turbocharger too.


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## Csch605 (Nov 26, 2018)

gjs238 said:


> Why did the P-39 perform, or seem to perform, so much more poorly than the P-40 - particularly in the early war years?
> 
> Both were V-1710 powered, sans turbocharger with single stage/single speed supercharger.
> 
> ...


One advantage on muddy or sleet filled airstrips was that the tail of the P39 was high and dry. The P40 and all other fighters would literally get frozen in the mud or have sand dirt and extra water on takeoff cause issues. I saw on Hustons film in the Aleutians in 1942 that P39s could easily albeit very slowly plow down the run way and takeoff. Russians also liked the tricycle gear for this reason. They also had an easier time with cold weather takeoffs with the liquid cooled not radial engines. The radials would actually need heating elements prodded in the front of of the motor and wait until it was warm enough to ignite. The antifreeze in the P39 would allow a subzero start up and go with the pilot prying open a frozen door. Prying open an iced canopy I gather would be more difficult than walking into the side door.

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## tomo pauk (Nov 26, 2018)

Csch605 said:


> The turbochargers were given to the P38 due to politics and scarcity of turbochargers. tHe P38 was a fine plane but was used 2 turbochargers two motors and over twice the materials. The P40 could have used the turbocharger too.



Don't fall to the 'not enough turbos' myth - XP-39 turbo installation was awful from drag standpoint, the XP-39 being unable to beat 350 mph mark as designed. Coupled with USAAC need to get a modern fighters in short time, turbo installation was deleted for on the XP-39B, and altitude-rated V-1710 was installed. On the P-38 turbo at least worked, and with less drag issues.
USA was not the only power to go with 2-engined fighter, the P-38 being an actually useful machine, with excellent performance when compared with US fighters of the time, and vs. many foreign fighters.
Granted, the P-40 with turbo would've been interesting. Unfortunately, the (X)P-40H never materialized.


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## swampyankee (Nov 26, 2018)

I’m sure this was addressed before (I’m on my phone, so scanning several pages is difficult), but the P-39 prototype was turbocharged. Bell did such a poor job with the installation that performance was improved with the turbocharger’s removal.


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## wuzak (Nov 26, 2018)

Csch605 said:


> The turbochargers were given to the P38 due to politics and scarcity of turbochargers. tHe P38 was a fine plane but was used 2 turbochargers two motors and over twice the materials. The P40 could have used the turbocharger too.



The P-40 was designed specifically to *not* have a turbo. This was after Curtiss' experience with the XP-37 and YP-37s.

Later there was a push for a turbo version, not sure why it didn't get past the proposal stage. Perhaps production was more important at that stage.

Curtiss did build a version of the P-60 with Allison V-1710 and GE turbo, the XP-60A (XP-60 was powered by V-1650-1, XP-60B was to be V-1710 + experimental non-GE turbo, XP-60C and E by -2800s and the XP-60D was powered by a V-1650-3).

The original installation was deemed a fire hazard by the USAAF, and had to be redesigned. The XP-60 used a P-40 fuselage with laminar flow wings, so the installations could have carried over.

But I'm not sure it would have been all that successful, or timely.


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## BiffF15 (Nov 26, 2018)

tomo pauk said:


> Don't fall to the 'not enough turbos' myth - XP-39 turbo installation was awful from drag standpoint, the XP-39 being unable to beat 350 mph mark as designed. Coupled with USAAC need to get a modern fighters in short time, turbo installation was deleted for on the XP-39B, and altitude-rated V-1710 was installed. On the P-38 turbo at least worked, and with less drag issues.
> USA was not the only power to go with 2-engined fighter, the P-38 being an actually useful machine, with excellent performance when compared with US fighters of the time, and vs. many foreign fighters.
> Granted, the P-40 with turbo would've been interesting. Unfortunately, the (X)P-40H never materialized.



Tomorrow,

I’m unfamiliar with the XP-40H. I found nothing on google. Pass a link if you have one please!

Cheers,
Biff


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## CORSNING (Nov 26, 2018)

The designations P-40H and P-40I were never assigned to any Curtiss
aircraft. Neither designation was assigned to any projects that I am 
aware of either.


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## tomo pauk (Nov 26, 2018)

BiffF15 said:


> Tomorrow,
> 
> I’m unfamiliar with the XP-40H. I found nothing on google. Pass a link if you have one please!
> 
> ...





CORSNING said:


> The designations P-40H and P-40I were never assigned to any Curtiss
> aircraft. Neither designation was assigned to any projects that I am
> aware of either.



Tomorrow - that's hilarious 
At pg. 162 of 'Vee's for victory', it is said that XP-4H was designation for the never produced variant of the P-40E. GE shipped a Type B-2 turbo to Curtiss 'immediately' after the Curtiss received authority for the project, that being June 19th 1941. However, by October 1941 that decision was revoked, the P-60 instead got the green light.
IIRC the designations ending with 'I' were never alloted due to fear that they might be confused with 'J' designations.

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## fliger747 (Nov 26, 2018)

A lot of the Lend Lease P-39's came through Fairbanks, where I live. No stranger to Winter aircraft ops, neither inline or radial engines are starting at zero (F) without preheat. Yes the anti freeze (glycol mixture) might provide freeze protection well below zero, it needs to be heated to loosen up the oil enough to provide lubrication on startup. The cold mixture plus cold oil and resulting slow turnover are big obstacles! Sometimes with a radial you can get a couple of jugs going (only the top cylinders have prime) and eventually coax out a quorum. currently used air cooled piston engines use either electric cylinder heaters or a source of hot air, such as the famous "Herman Nelson" heater. No one that I know currently flies a liquid cooled aircraft engine in Arctic conditions, but our automobiles use electric block heaters of various types. 

My (limited) understanding of the impetus behind the mid engine design was to reduce the pitch inertia by concentrating the mass toward the center.

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## Csch605 (Nov 26, 2018)

BiffF15 said:


> Tomorrow,
> 
> I’m unfamiliar with the XP-40H. I found nothing on google. Pass a link if you have one please!
> 
> ...


Issue with the P38 is that it got to the party so late. It missed 1942 in the Pacific and Nort Africa and the Russian front. The battles where the Allies won the war. P38, Vought Corsair, Hellcat, P51, P47 were still in development re-development, flight testing etc. Theier tardy designs got alot of Kamikazes and novice German pilots who never even got a shot off if they had machine guns at all. In 1942 the US and Australian and New Zealand pilots had almost no combat experience and less than oe equal to 40 hours of flight time.


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## CORSNING (Nov 26, 2018)

tomo pauk said:


> Tomorrow - that's hilarious
> At pg. 162 of 'Vee's for victory',* it is said *that XP-4H was designation for the never produced variant of the P-40E.
> 
> *It is said? Tomo, is there any indication WHO "it is said" by? Is there any elaboration
> on the subject in 'Vee's for Victory'?*


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## tomo pauk (Nov 26, 2018)

CORSNING said:


> _It is said? Tomo, is there any indication WHO "it is said" by? Is there any elaboration on the subject in 'Vee's for Victory'?_



It is said by 'Aircraft and Jets', Vol.1 No.1 pg.17, June 1946, in article 'Evolution of P-40'. The delivery of turbo was footnoted: Teletype E-106 and PROD-T-665 of 6-10/12-1941 to Chief, Material Division, Wright Field; NARA, RG 342, RD 3466, Box 6841.

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## wuzak (Nov 26, 2018)

fliger747 said:


> My (limited) understanding of the impetus behind the mid engine design was to reduce the pitch inertia by concentrating the mass toward the center.



It was all about the gun, the 37mm M4 cannon.

Some proposals were made by Bell where the engine drove an extension shaft to the prop so that a big cannon (25mm or 37mm) could fire through the prop. Some of these had the engine ahead of the pilot, the one that got the contract was, obviously, the mid-engined version that became the P-39.

http://bellaircraftmuseum.org/sites/default/files/bell_model_3_0.jpg
http://bellaircraftmuseum.org/?q=node/32


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## GregP (Nov 26, 2018)

According to Don Berlin's son, the P-40 was designed to include a turbo but was never allowed to get one in practice. He never said if this resulted in a shorter fuselage, but I'd surmise that if the contention is true, then there was some length deleted when the turbo didn't materialize. If that is NOT true, then the P-40 does not appear, to me at least, to have room for a turbo package in the existing short-fuselage version. Maybe in the long-fuselage version, as in a P-40M.

Don's son also said Don was allowed to build ONE P-40 with a turbo and that it gave great high-altitude performance. But I have never personally seen anything that would support that statement. That is, I've never seen anything that can be used to reference a turbo P-40 being actually completed. So, I have no personal knowledge of the subject to conform or deny it. I HAVE heard of P-40s being flown at 75" MAP and performing quite well with no detrimental effects being noticed upon return to field, and have spoken with a guy who flew the twin P-40 (see below):







But even HE never heard of the flying turbo P-40. I would surely like to have seen a turbo XP-40Q, for sure, or an XP-40Q with a 2-stage Merlin. Alas, neither were built.


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## wuzak (Nov 26, 2018)

Curtiss had a turbo V-1710 development of the P-36 - the P-37.

The turbos were unreliable, especially in the XP-37, less so in the YP-37.

From that experience Curtiss and Don Berlin sough a non-turbo "altitude rated" V-1710 to put with the P-36 airframe, this becoming the P-40.

The P-40 was even in competition with the P-37, and others, for a production contract, IIRC.

We do know that the P-40 fuselage could mount a turbo system, as the P-60 used an early model (P-40D or P-40E) fuselage.

But the P-40 was not designed to use a turbo, though a proposal for a later model turbo version was made.


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## Shortround6 (Nov 30, 2018)

wuzak said:


> We do know that the P-40 fuselage could mount a turbo system, as the P-60 used an early model (P-40D or P-40E) fuselage.
> 
> But the P-40 was not designed to use a turbo, though a proposal for a later model turbo version was made.



Well, there is mounting a turbo in a P-40 fuselage and there is mounting a turbo in a P-40 fuselage.





This is the P-60A with the turbo Allison. Please note this aircraft has a 275sq ft wing. 




It may have started as a P-40 fuselage but apparently a lot extra _fairing_ was needed to hide all the turbo bits and pieces. Wingspan was 41 feet and it used a 11ft 8in prop. for it's 1425hp engine. 

I would also note that the book " Curtiss Fighter Aircraft 1917-1948: a Photographic History" by Francis H. Dean & Dan Hagedrom 
makes no mention of a P-40H and under the designation for P-40J simply says that while some sources claim that is the designation used for the turbo P-40E project ant that it was abandoned in May of 1942 no Cutiss records located at the time the book was published confirm the project. No AAF documents have been identified as confirming the project and an official AAF document "Model Designations Army AIrcraft" fated July 1942 says that the P-40J designation had not been assigned. 

Please note that some sources say that Don Berlin had left Curtiss in April of 1942 to go to Fisher to work on the P-75. The above P-60 had been proposed and approved much earlier and indeed a contract for 1950 such aircraft had been given to Curtiss in late Oct 1941 only to be canceled right after Pearl Harbor. (Jan 1942) and the P-60 didn't commence testing until Oct of 1942 and the turbo was removed before the first flight in Nov.


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## P-39 Expert (Nov 30, 2018)

This is the problem with a turbo in a single engine plane. No matter what you start out with you end up with a P-47.

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## Milosh (Nov 30, 2018)

Or a Bv155.


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## tomo pauk (Nov 30, 2018)

P-39 Expert said:


> This is the problem with a turbo in a single engine plane. No matter what you start out with you end up with a P-47.



There is a small thing on the P-47, called the R-2800. As conceived, it was to offer an extra 3/4s of power vs. V-1710. Price being weight and size, not just of the engine, but of necessary plumbing, turbo and intercooler. Big fuel tank is needed, since big power needs a lot of fuel. Now that we're to install a 2000 HP engine on a fighter, a suitable armament s needed - 8 HMGs. As before you know it, the fighter gets big & heavy.

We can recall that P-43 was smaller than Hawker Hurricane or F4F, neither of the 3 being slim. On the other hand, Hellcat didn't needed a turbo to be as big as P-47.


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## Shortround6 (Nov 30, 2018)

It depends on how you measure size. The P-43 was certainly a heavy airplane for it's "small" size.
tested gross weight was 6918lbs with 145 US gallons of fuel on board which makes a P-43 about 400lbs lighter than a 12 gun Hurricane. 
This P-43 weight is with two .50 cal guns and two .30 cal guns, no armor, no self sealing tanks. 
Production P-43s were even heavier and the P-43A with four .50s was even heavier. 
The light weight P-43 had trouble out climbing the Hurricane II and needed a bigger airfield.


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## P-39 Expert (Nov 30, 2018)

tomo pauk said:


> There is a small thing on the P-47, called the R-2800. As conceived, it was to offer an extra 3/4s of power vs. V-1710. Price being weight and size, not just of the engine, but of necessary plumbing, turbo and intercooler. Big fuel tank is needed, since big power needs a lot of fuel. Now that we're to install a 2000 HP engine on a fighter, a suitable armament s needed - 8 HMGs. As before you know it, the fighter gets big & heavy.
> 
> We can recall that P-43 was smaller than Hawker Hurricane or F4F, neither of the 3 being slim. On the other hand, Hellcat didn't needed a turbo to be as big as P-47.


I can't tell if you are agreeing with me or not.  The turbo itself, all the internal ducting to and from the turbo, the intercooler and it's ducting all make for a much larger single engined plane. Compare the photo of the P-60 with a P-40. Multiengined planes (P-38, B-17 etc) have more internal room for the turbos.


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## tomo pauk (Nov 30, 2018)

P-39 Expert said:


> I can't tell if you are agreeing with me or not.  The turbo itself, all the internal ducting to and from the turbo, the intercooler and it's ducting all make for a much larger single engined plane. Compare the photo of the P-60 with a P-40. Multiengined planes (P-38, B-17 etc) have more internal room for the turbos.



My point is that any item on aircraft can influence the size. Obviously, the bigger and/or heavier item in question, the bigger and/or heavier the plane ends up; more items will also up the weight and size. The P-47 being the case in point.
On the other hand, plenty of 1-engined A/C didn't needed turbo and it's anciliaries to end up big and heavy, while some of turboed 1-engined A/C were still of modest size and weight.


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## Shortround6 (Nov 30, 2018)

The P-60 was also porked up by carrying 200 us gallons internal and an expected ( but not fitted) eight .50 cal guns.
The P-43, which may be one of the few "small" turbo charged fighters to actually go into production (at least in the western allies) was also somewhat cursed by using the standard Seversky fuselage which was easily adaptable to a two seater. Plenty of room for the for the turbo but hardly the smallest/lightest airframe possible.
The last versions built would have grossed around 7500lbs clean.


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## wuzak (Nov 30, 2018)

P-39 Expert said:


> I can't tell if you are agreeing with me or not.  The turbo itself, all the internal ducting to and from the turbo, the intercooler and it's ducting all make for a much larger single engined plane. Compare the photo of the P-60 with a P-40. Multiengined planes (P-38, B-17 etc) have more internal room for the turbos.



You have made the assumption that all turbo single engine aircraft had to have acres of ducting and have the turbo in the rear fuselage, like the P-47.

The P-60A had the turbo up the front, from what I understand. The rear fuselage is no much deeper than a P-40, if at all.



Shortround6 said:


> Well, there is mounting a turbo in a P-40 fuselage and there is mounting a turbo in a P-40 fuselage.
> 
> View attachment 519757
> 
> ...



The Curtiss XP-37 and YP-37 were converted from the P-36.






Curtiss P-36 Hawk - Wikipedia

The YP-37 was 25 inches longer than the XP-37, but only 15.5 inches longer than the P-40E.

The fuselage modifications were mainly to move the pilot back to make space for the intercooler, radiator, fuel tank and oil tank. You can see the turbo under the fuselage, just forward of the wing, including the wastegate pipe.

If Curtiss was to convert the P-40 to a turbo aircraft, they no doubt would have kept the turbo's placement similar to the YP-37, but would have, most likely, kept the radiator up front like the P-40 and expanded the duct to include the radiator. And teh nose would look a lot like the P-60A.

For comparison, this is the XP-60D, powered by the Packard Merlin V-1650-3





And the XP-60E, powered by the R-2800





Both from Curtiss P-60 - Wikipedia


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## Shortround6 (Dec 2, 2018)

While these drawings may not be 100% accurate we can see that the turbo P-60A was significantly fatter than the Merlin powered XP-60 and P-60D.
Vents/ louvers are behind the cockpit showing that some part of the turbo system was back there. 
Trying to add everything necessary for a turbo system forward of the CG on a P-40 is not going to work well.

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## michaelmaltby (Dec 2, 2018)

... when I see all of the design variants ... from P-40 lookalikes to a sleek Jug-like P-60 ... I have _renewed respect_ for Curtis Corp. .... they remained strong ... and by this time the P-40 designer Don Berlin had abandoned Curtis and jumped ship to Fisher, IIRC ... the company was among America's largest ... was strong going into war ... clearly strong, but with problems (P-47 build), during the war, _yet_, the company as it was in 1945 just tumbled into pieces ... North American Aviation, Republic and Grumman were the new top dogs.


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## wuzak (Dec 2, 2018)

Shortround6 said:


> View attachment 519999
> 
> 
> While these drawings may not be 100% accurate we can see that the turbo P-60A was significantly fatter than the Merlin powered XP-60 and P-60D.
> ...



Yes, it does look fatter. It looks more like the R-2800 powered P-60s than the Merlin powered ones.

The P-60C and P-60E show vents in a similar area to the P-60A, but neither the C or E had a turbo.


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## Shortround6 (Dec 2, 2018)

wuzak said:


> Yes, it does look fatter. It looks more like the R-2800 powered P-60s than the Merlin powered ones.
> 
> The P-60C and P-60E show vents in a similar area to the P-60A, but neither the C or E had a turbo.


True but the R-2800s used did have a two stage supercharger and indeed one of the engines used was the same one as the F6F used.
It may not have needed the size intercooler the P-47 used but it did need an intercooler.


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## Reluctant Poster (Dec 2, 2018)

michaelmaltby said:


> ... when I see all of the design variants ... from P-40 lookalikes to a sleek Jug-like P-60 ... I have _renewed respect_ for Curtis Corp. .... they remained strong ... and by this time the P-40 designer Don Berlin had abandoned Curtis and jumped ship to Fisher, IIRC ... the company was among America's largest ... was strong going into war ... clearly strong, but with problems (P-47 build), during the war, _yet_, the company as it was in 1945 just tumbled into pieces ... North American Aviation, Republic and Grumman were the new top dogs.


What I see is the last gasp attempts of a failing company. Despite Curtiss having the advantage of a large factory ready for production and being given the opportunity to develop several different designs, they were unable to win any orders. In fact the USAAF cancelled an order for 1900 P-60s as it was not performing anyway near expectations. With the end of P-40 production they were out of the fighter business. Meanwhile they were destroying their reputation in other categories with the SB2C, C-46, C-76 and SO3C. Curtiss was finished long before 1945.
As for Don Berlin I don’t see how he could have helped. The Frankenstein creation that was the XP-75 is the exemplar of how not to design an aircraft. the attached PDF is the sordid history of the XP-75.


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## Greg Boeser (Dec 2, 2018)

Csch605 said:


> Issue with the P38 is that it got to the party so late. It missed 1942 in the Pacific and Nort Africa and the Russian front. The battles where the Allies won the war. P38, Vought Corsair, Hellcat, P51, P47 were still in development re-development, flight testing etc. Theier tardy designs got alot of Kamikazes and novice German pilots who never even got a shot off if they had machine guns at all. In 1942 the US and Australian and New Zealand pilots had almost no combat experience and less than oe equal to 40 hours of flight time.


P-38Es (54th FS) arrived in Alaska in June 1942 and were immediately put to use flying long-range escort and sweeps from Unmak Island to Kiska, 617 miles one way. The first P-38Fs (1st and 14th FGs) arrived in England in the Fall of 1942 and flew a few ops before transferring to NW Africa following the Torch landings. 82nd FG soon followed with P-38Gs. the 78th FG was supposed to operate P-38s from England, but had to give up all their planes and most of their pilots in Feb 1943 to the NW African based groups to replace the heavy losses incurred by these units. The 78th re-equipped with P-47s before becoming operational in April 1943. P-38s did not return to European skies until October 1943, with the arrival of the 20th and 55th FGs.

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## Schweik (Dec 6, 2018)

While I personally agree the tipping point of the war was in (fall) 1942, things were still pretty up in the air through the middle of 1943. And P-38s were certainly making a difference in the Med and the Pacific during those crucial months. It's one thing to tip the balance, but it's another to really start the momentum going and keep it moving in the right direction long enough that the enemy can't recover. And the pressure was certainly on very heavily all through 1943.

P-38s were important due especially to range in the Pacific and both range and altitude performance in the Med where they flew escort to mostly the four engine bombers, B-17s and B-24s. The latter were surprisingly effective and useful in destroying enemy airfields and aircraft, but were also quite vulnerable to fighters and took serious losses. The P-38s took horrible casualties but seem to have given about as good as they got as the saying goes, based on what I can read in Christopher Shores Mediterranean Air Wars, Vol IV of which is out now by the way

In that fourth volume of his series incidentally you do see a couple of occasions where P-39 units scored some real verifiable victories, including at least one day where they came off pretty well in a clash with some FW-190s. You really don't see that at all in Volume III. Maybe the pilots got a little more used to them. But that gives us a hint that American pilots might have had the same kind of successes with them that the Soviets did under the right circumstances (what those circumstances would be precisely I don't know).

P-40s were being used in fighter sweeps and escort missions (mostly for B-26s and other medium bombers, as well as for A-36s) at a high rate through mid 1943, particularly at Pantelleria, over Sardania and Sicily where I would say from the records Shores shows us, P-40s were more than holding their own against German and Italian fighters (the former including Fw 190s and G series 109s and the latter including both MC 202 and MC 205, Re 2002 and later G55s). Certain P-40 units in particular clearly did have the good kill / loss ratio in air to air combat that they claimed to have and merited their reputation, certainly you don't see the kind of losses that the RAF suffered in 1942. In mid 1943 some of these US P-40 units started switching to P-47s. By that point the Italians are also basically out of the fight.

After mid 1943 P-39s are being used mostly for coastal defense and maritime patrol, but coming into the fight more than previously due to Axis attacks on Allied shipping The P-40s are being used more for ground attack, though still engaging with enemy fighters frequently. There is another flare up of air to air combat near and around Anzio in January and February 1944 where US P-40 squadrons are repeatedly clashing with Bf 109s and FW 190's and still seem to have held their own. The P-47s don't seem to be doing any better than the P-40s in terms of real victory to loss ratios. The last significant dogfight I found involving P-40s was September of 1944. They were not taking heavy losses at any time in 1944 from Axis fighters, most of their losses were from flak during ground attack missions. P-47s were about the same. By contrast P-38s were taking heavy losses sometimes as many as 10 -12 on a single day. P-40 units were getting in large scale fights with Axis fighters (30-40 on both sides) but suffer 2-3 losses and scored at least that many victories (though sometimes it's hard to be certain who got what victory especially later in 1943 and into 1944).

In contrast to the Americans the RAF seems to have relegated almost all of it's P-40s to a pure FB role by mid 1943, with the Spitfire IX and increasingly, VIII's taking the lead..This may be because they didn't get very many of the Merlin powered P-40s in their arsenal (with only two squadrons so equipped) so couldn't fight at the higher altitudes. Anyway they made very few claims and mostly seemed to suffer heavily from Flak and ground fire. The A-36s seemed to also take very heavy casualties.

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## Schweik (Dec 6, 2018)

I'm going to do some longer and more thorough posts from the MAW stuff in the P-40 vs 109 thread, but I thought some of it was relevant to the discussion here.


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## Schweik (Dec 7, 2018)

So one of the incidents I mentioned with the P-39s was *Friday June 11, 1943*, during the destruction of Pantelleria. During a long day of intense raids, Allied aircraft bombed the island and intercepted Jabos sent to attack the landing fleet which was on the way. It's hard to be certain what happened exactly based on the data but it looks like the P-39s didn't get slaughtered anyway.

There were multiple claims by Allied fighters made through the day:

10:30 -11:00 P-40Fs from the 57th Fighter Group claimed 2 x Bf 109s destroyed and Spitfires from the 31st Fighter Group claimed 1 Fw 190 destroyed and 2 damaged
12:30-13:45 Spit IX's from the 31st Fighter Gorup claimed 5 x Bf 109s destroyed +1 damaged
12:40 a P-38 from the 1st FG claimed a Bf 109 'probable'
13:00 P-39s from the 93rd FS, 81st FG claimed 3 Fw 190s destroyed and 1 probable
13:00 A Free French Spitfire from GC 1/7 claimed a Fw 190 destroyed
15:40 Spitfires from the 31st FG claimed 5 FW 190s destroyed and 1 Fw 190
18:14 English Marauder I gunners claimed 1x Bf 109 destroyed and 1 damaged.

Allied losses for the day were 2 x Spit Mk V's from 31st FG and 1 B-26 lost to flak.

This is Christopher Shores commentary on the mid day part of the battle:
_"...a raid was made by FW 190s but was intercepted by P-39s of the 81st Fighter Groups 93rd Squadron and French flown Spitfires of GC 1/7. Here the defending fighter pilots claimed 4 Jabos for the American pilots and one for Sgt Chef Louis Kahn, the former a most unusual success for the frequently ill-fated Airacobras."_

Total claims were for 18 'confirmed' victories.

Actual Axis losses were 7 aircraft: 2 x Bf 109G-6s from JG 53, 3 Fw 190A-5s from Sch G 2 (ground attack) and 1 x MC 205s from 360 sq and 1 x MC 202 from 160 Sq.

Two of the Fw 190s were lost at 10:45 and one at 13:00 but there were no times indicated for the other losses.

It was certainly a busy day with the usual overclaiming but it is clear that the P-39s didn't suffer any losses in the combat and seems likely that they shot down at least one of the Fw 190s lost that day, although it could have also been the French Spit.



A more clearly defined incident took place three days earlier on *Tuesday June 8*, also near Pantelleria,

Around midday a P-38 from the 1st FG claimed a Fw 190 at 13:35 and Spitfires of the 31st FG claimed 1 x MC 200 out of a group of them which were attacking Allied torpedo boats at 13:35.

At 1910 hours in the evening, 15 x P-40Fs of the 85th Fighter Squadron, 79th Fighter Group were performing a sweep ('armed reconnaissance') over the Island when they were 'jumped' by 11 Macchi 205s, 6 (Italian flown) Bf 109G, and 20 x Macchi 202s. Some of the latter were attempting to attack a large group of B-17s while some attacked the P-40s.

In the ensuing combat 79th FG P-40Fs claimed 6 enemy fighters, while the Italians claimed 8, plus a four engined bomber.

Actual Allied losses for the day were 1 Spitfire shot down and 1 damaged, both in the morning..

Actual Axis losses were 5 Italian fighters - 2 x Macchi 205 and 3 x Macchi 202. All of these losses were during an engagement in the "early evening"

Because of the reported time of the combat by the Italians, I think it's fair to say the 79th FG P-40s got them.

There were several incidents like this during May through July of 1943 involving American P-40 units.

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## P-39 Expert (Dec 8, 2018)

Here's a chart of the P-39K vs the P-40E in red and P-40F (Merlin) in black. These are representative of the early models with the 8.8 supercharger gears in the Allison.

As you can see the Merlin provided the P-40F with substantially improved performance both in speed and climb over the P-40E. The P-40E clean without drop tank climbed at about the same rate as the P-39K WITH a drop tank. Climb was the major problem for both these planes. Combat ceiling was generally described as the altitude at which a plane could no longer climb at over 1000ft/min. A clean P-40E (virtually all AAf fighters carried drop tanks on combat missions) could barely climb to 19000' which is too low for almost any combat theater. Add the ubiquitous drop tank and combat ceiling was even lower.

Even after the significant performance increase provided by the Merlin the P-40F was still slower than the P-39K up to 20000'. Climb would have been about the same for both planes at 3000rpm (combat power). Climb on the chart was at 2850rpm for the P-40F and 2600rpm for the P-39K above 12500'.

Weight was the major problem for both these planes. The P-40E weighed 8260# clean and the P-39 weighed 7650# while a comparable SpitfireV weighed 6600#, a 109G weighed 6900# and an early Zero weighed 5500#. 

In summary the P-39K performed substantially better than the P-40E and a little better then the P-40F. Later (Nov. '42) Allison models with the 9.6 supercharger gears provided substantial performance improvements for the P-39N and the P-40N but the P-39N was still substantially faster and climbed a lot faster than the P-40N. Any perceived superiority of the P-40 was due to pilot quality of both the AAF and their opposition.

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## taly01 (Dec 8, 2018)

By paper statistics the P-39 seems to be superiour to the P-40 yet the USAAF clearly preferred the P-40, i can't ever recall reading a US pilot praising or liking the P-39. It would be nice to see US pilots opinions of those who flew both P-39 and P-40. I wonder if the P-39 mid-engine effected common combat aerobatics? ie. the P-40 was meant to be good at high speed Split-S the engine in nose probably helped that? In reverse the P-39 was meant to have some dangerous spin characteristics due to the weight been in the centre of the plane.


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## P-39 Expert (Dec 8, 2018)

taly01 said:


> By paper statistics the P-39 seems to be superiour to the P-40 yet the USAAF clearly preferred the P-40, i can't ever recall reading a US pilot praising or liking the P-39. It would be nice to see US pilots opinions of those who flew both P-39 and P-40. I wonder if the P-39 mid-engine effected common combat aerobatics? ie. the P-40 was meant to be good at high speed Split-S the engine in nose probably helped that? In reverse the P-39 was meant to have some dangerous spin characteristics due to the weight been in the centre of the plane.


I'm inclined to agree with you that the AAF probably preferred the P-40 although I can't see why. Chuck Yeager always said the P-39 was his favorite plane (until he got a P-51B) and he also said he didn't know anyone who didn't like the P-39. He was flying later models of the P-39 in training. Big difference in performance with the P-39N over the earlier models.

Common aerobatics were not affected, the P-39's CG was about the same as other single engined planes. Taxi, takeoff and landing were much easier. It was said that the P-40s were slightly more maneuverable than P-39s although their wing loadings were about the same.


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## Greyman (Dec 8, 2018)

Got a few quotes from a quick skim of Shores' latest - A History of the Mediterranean Air War Volume Three

1/Lt. Jerry Collinsworth, 307th Squadron, 31st FG
_The P-39 was a miserable fighter for Tunisia; we used to have to escort them because the Bf and FW outperformed them in every conceivable way; dive, manoeuvre, speed – you name it! The Kittyhawk was very little better._

Lt. Jack G. Walker, 97th Squadron, 82nd FG
_In May 1943 I was transferred to Casablanca to help in the reorganisation of the Free French air force, just equipped with the P-39 Airacobra. ... Our accident rate was tragic due to the overheating engine and some stability problems with the P-39._

Capt. John L. Bradley, 58th and 59th Squadrons, 33rd FG
_The P-40 was an untried aircraft in Europe and it just didn't have the performance to compete when it did arrive. It was capable of taking a lot of punishment and coming home, and it did possess good firepower. However it was obsolete for the job it was called on to perform. ... I flew a couple of escorts to P-39s during my tour. Many of the pilots of these aircraft were afraid of them and figured they didn't have a chance if they were jumped by enemy aircraft without top cover._


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## Schweik (Dec 8, 2018)

P-39 Expert said:


> Here's a chart of the P-39K vs the P-40E in red and P-40F (Merlin) in black. These are representative of the early models with the 8.8 supercharger gears in the Allison.
> 
> As you can see the Merlin provided the P-40F with substantially improved performance both in speed and climb over the P-40E. The P-40E clean without drop tank climbed at about the same rate as the P-39K WITH a drop tank. Climb was the major problem for both these planes. Combat ceiling was generally described as the altitude at which a plane could no longer climb at over 1000ft/min. A clean P-40E (virtually all AAf fighters carried drop tanks on combat missions) could barely climb to 19000' which is too low for almost any combat theater. Add the ubiquitous drop tank and combat ceiling was even lower.
> 
> ...



Couple of points on the above...

The P-39s mentioned in Volume IV of MAW were P-39L, which I had never even heard of. Is that V-1710-85? But anyway I think the ones they were using in some of the earlier debacles in fall 1942 or winter 42/43 were much earlier versions. Not certain though I'd have to check.

The P-40E's as delivered and under official rules for engine management were quite underpowered but they seem to have worked around that by mid 1942 in the Med. Of course only the English and the Russians ever used P-40E's as far as I know. Initially the Kittyhawks (P-40D and E) were doing worse than the Tomahawks, but various changes to engine management and / or maintenance seemed to have changed that by mid 1942, coinciding with a change in strategy. Per Australian double P-40 Ace Bobby Gibbes:

_"Well it was basically the same aeroplane. We were a little disappointed when we first got the Kitty, we thought it'd be way ahead of the Tomahawk. In actual fact, it was a little bit better. One thing I personally didn't like about it was the Tomahawk had fairly high sides and you'd be sitting behind a thin sheet of metal but you felt safer. The Kittyhawk had perspex coming way down and you felt as if you were sitting up, very vulnerable, because you could see out so much. That was one feature I do remember. *However, later when we got our Kittyhawks running properly - were getting better performance - they were a better aeroplane.*" _

Partly this means they were replacing older V-1710-39 Allisons with more robust V-1710-73 of the P-40K. Partly it meant overboosting and other engine management changes.
By 1943 English are mostly using Kittyhawk III (either P-40K or M, the former having much better low altitude performance, with 1550 hp at WEP / 60" Hg or 1325 hp at military power / 51" Hg, the latter better high altitude - higher effective ceiling- but lower powered overall).

As far as altitude, it's in some ways even worse than most people think - the performance ceiling for the low-geared V-1710-39 and 73 was actually at about 12,000 feet, only the higher ratio engines could manage the oft cited 15 -16,000 ft, and the lightened "high altitude" P-40Ns were still performing reasonably well at 17,000 ft. But they did routinely operate well above those altitudes using special tactics. There is a detailed defense industry blog article about how they were able to successfully use P-40E in the defense of Darwin, where lets not forget for whatever reason they had more success than Spit Mk V's did, and elsewhere in the Pacific and especially the CBI they were flying them at much higher altitudes on a routine basis, including escorting transports over the Himalayas. The jist of it seemed to be that they could pick up speed so well in a dive, extend and then (however long it took) climb back up, and they operated in smaller flights of 4 aircraft.

This wasn't really an option though in the Med where the much better organized German opposition required them (and basically all Allied fighters) to operate in Squadron sized units of 8-15 basically all the time. They were also able to use the radio a lot more in the Pacific apparently, at least according to some of the Australian pilots who were brought from the Med to the Pacific. The Germans were very efficient at locating the source of radio transmissions.

The bottom line on the P-40E is that it was used effectively against enemy aircraft in the Med, in the Pacific and CBI, and in Russia. We can say that the P-39 was used effectively in Russia. The P-39 had better climb but there is more to "performance" than climb rate.

I think the difference between the two aircraft may boil down to ease of handling and training. One common thing with many Allied fighter squadrons in 1941 and 1942 was that they were given badly inadequate transition training on the actual aircraft they were going to have to use in combat. Some of the Australian P-40 pilots who fought at Milne Bay, Darwin and the Kokoda trail for example had less than 10 hours training on the type before they were ferrying them into battle and then fighting. They actually lost more in landing accidents, maintenance issues and from getting lost on ferrying flights than they did in combat. Clive Caldwell the Australian P-40 ace noted how little airfcraft specific combat training they had received on the P-40 in North Africa and he set about trying to establish some. But as tough as it was to get used to, and I don't think it was "easy" to fly (clearly more challenging than the Hurricane for example), I think the P-40 pilots were able to get to competence in a few weeks whereas with the P-39 in the Med and Pacific it seems it took them longer, and some of them never learned to trust the plane because they didn't have a sense how far they could push it in turns and vertical maneuvers.

For the Americans, British and Anzac pilots, the P-40s had serious limitations but the limitations were _known_ and pretty well understood, so they fairly quickly developed strategies that allowed them to work around these flaws and exploit their avantages.

The Russian pilots by contrast had often transitioned from I-16s, MiG 3's, LaGG-3's and other aircraft which were notoriously unstable and twitchy so for them the P-39 may have actually been an improvement in that department, and as I have pointed out somewhere in the forum before, from the Lend Lease.RU article on the Soviet use of the P-39 we know that they did an almost 4 month workup on the aircraft before sending it into battle, which means that you had at least some pilots who knew the limitations of the fighter in maneuvering and some institutional knowledge as to how best to use it. I suspect that may be the real difference.

My other theory is that the P-39 may have just flown better in cold air but I'm not sure if that's really it, summers were hot on the Russian Front particularly in the Southern reaches Crimea etc.


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## Schweik (Dec 8, 2018)

As for who liked what plane, I haven't yet read any American or Western / Allied pilot who liked the P-39 (the John Glenn thing is new to me though I'm not disagreeing) but of course for the Soviets it was _by far_ their favorite Lend Lease fighter. P-40s were disparaged by Anglo-American military leadership and administrators, for understandable reasons (the altitude limitation was a serious flaw) but a lot of the pilots did like it and weren't shy about saying so. Some didn't that is certain, including some high scoring P-40 aces for example Neville Duke. But it's not hard to find those that did.

AVG pilot Erik Shilling was a well known advocate for the P-40. Some of his comments included _"If you look up maneuverable in Webster's Dictionary, by all criteria the P-40 was more maneuverable. "_ and "_The P-40 was faster (354 mph with combat load vs a little over 300 for the Zero), the roll rate at 240-280 mph was 3 times faster and the aircraft could outdive the Zero." _

Australian P-40 quadruple P-40 Ace and 112 RAF sqn commander Clive Caldwell said it had "_almost no vices_" and that it "_would take a tremendous amount of punishment, violent aerobatics as well as enemy action_"

Nicky Barr, 3 RAAF P-40 double Ace noted:

_"The Kittyhawk became, to me, a friend. It was quite capable of getting you out of trouble more often than not. It was a real warhorse."_

Robert DeHaven, 49th FG double ace and Silver Star winner, noted:

_"If you flew wisely, the P-40 was a very capable aircraft. [It] could outturn a P-38, a fact that some pilots didn't realize when they made the transition between the two aircraft. " _

and

_"[Y]ou could fight a Jap on even terms, but you had to make him fight your way. He could outturn you at slow speed. You could outturn him at high speed. When you got into a turning fight with him, you dropped your nose down so you kept your airspeed up, you could outturn him. At low speed he could outroll you because of those big ailerons ... on the Zero. If your speed was up over 275, you could outroll [a Zero]. His big ailerons didn't have the strength to make high speed rolls... You could push things, too. Because ... f you decided to go home, you could go home. He couldn't because you could outrun him. [...] That left you in control of the fight."_

_Nikolai Golodnikov said in an interview:_

_"Actually, the P-40 could engage all Messerschmitts on equal terms, almost to the end of 1943. If you take into consideration all the characteristics of the P-40, then the Tomahawk was equal to the Bf 109F and the Kittyhawk was slightly better. Its speed and vertical and horizontal manoeuvre were good and fully competitive with enemy aircraft. Acceleration rate was a bit low, but when you got used to the engine, it was OK. We considered the P-40 a decent fighter plane"_

General Benjamin Davis of the 99th FS ("Tuskegee") had a lot of praise for and confidence in P-40s:

_"The P-40 operations in the Pacific and Europe were much like the F-86 and the MiG in Korea*. All the MiG's had to do was stay away from the F-86's; yet we had an eleven-to-one kill ratio of F-86's over MiG's**. Same thing with the P-40 and the Me 109. If the German fighters wanted to stay away, the P-40's couldn't get them. When the Me 109's came down to engage the P-40's we were superior."_

Charlie Hall also 99th FS said:

_"The P-40? Sure we liked them. Most of us got home that flew them. I don't think the real potential of that aircraft was ever realized. Anyway that's what we had and it did the job. I fought with four .50s. Took out the other two so I could carry more ammunition. "_

Tenth Air Force pilot Bob O'Neil (16th FS, 4 victories) ... who was stationed in the Assam Valley India and in Burma and fought over the 'hump' in the Himalayas, said:

_"I loved those P-40's. They had their faults; but they'd get you home when nothing else would. All our battles with the Japs were between 15,000 and 20,000 feet. We couldn't out-maneuver their fighters but we could out-dive them and the Hawk would take more punishment than anything we met. It was a sturdy, fine airplane."_

RAF 24-kill Ace Billy Drake (13 victories in the P-40) praised the heavy guns of the Kittyhawk and said in this interview:

_"Altogether, air to air it was just as good as anything we were liable to meet.” "The six 0.5 guns had a terrific effect" “If you were caught out, if you put it in a dive it went very fast”_

I can post plenty more examples if needed.

*General Davis was Director of Operations and Training, FEAF, Japan, fought over Korea and was commander of the 13th AF during the Korean War)
**I know this isn't the actual ratio that is just a direct quote


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## eagledad (Dec 8, 2018)

Schweik,

The P-39K and P-39L both used the V-1710-63 Allison. The only major difference between the 2 aircraft was that the K used an Aero company propeller, the L used a Curtiss propeller. The -63 Allison was rated at 1325hp for take-off and 1150 at 12,000 feet "Emergency Maximum. Data from Pilot Operating Instructions for P-39K-1 and P-39L-1, dated Dec 20, 1942.

Eagledad

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## Schweik (Dec 8, 2018)

Interesting, well 1,325 hp is pretty good. WEP at low altitude is probably a bit better.

As for the weight issue, I"m not sure I buy that the P-39 and P-40 were overweight, but I think they were initially underpowered which is not quite the same thing. Almost every pilot agrees that P-40s were plenty maneuverable and had no problem pulling tight turns. The wing loading was pretty low at least by ETO / MTO standards. The engines weren't that powerful though for a heavier fighter.

We perhaps tend to forget how many very heavy aircraft did well in the war. Normal loaded weight for a P-40 was between 7,600 lbs / 3450 kg (early Tomahawk) and around 8,400 (P-40K). P-39 was a bit less at around 7,000 - 7,500 lbs.

It's true that there were a lot of much lighter fighters around - the Ki-43 and A6M, the earlier Fiat and Macchi series, the Bf 109 and most of the Soviet fighters, Due to their light weight and powerful engines they had high power / mass ratios usually meaning good climb and acceleration. The Spitfire Mk V for example had a loaded weight of 6,240 with a 1,470 hp engine for a power ratio of 0.23. Later versions were even better. The A6M2 /21 had a ratio of 0.18 and the Bf 109F had a ratio of 0.17 at military power (1200 hp) or 0.19 (1305 hp)

But there were also a lot of comparatively _heavy_ fighters that also did quite well. I listed a few of the wars more successful (but heavy) day fighters with their "normal loaded" weights, engine power and power-weight ratio. This is quickly googled by the way so there may be errors, don't crucify me for it, most of these are from wikipedia or whatever credible looking site I could find. I got the 109F and Spit V stats from this site.

*Fw 190A-8* was 9,400 lbs loaded (but with a 1,677 hp engine) - 0.20 hp / lb power ratio
*Hawker Typhoon *was 11,400 lbs loaded (with a 2,200 hp engine) - 0.21 hp / lb power ratio
*Hawker Tempest V* was also 11,400 lbs loaded (with a 2,180 hp engine) / 0.21 hp / lb power ratio
*F4U-1 Corsair* was 11,878 lbs loaded (with a 2,000 hp engine) - 0.175 hp / lb power ratio
*F6F-5 Hellcat *was 12,598 loaded (wtih 2,200 hp engine) - 0.16 hp / lb power ratio
*Kawanishi N1K1-J* was 8,820 lbs loaded (with an 1,850 hp engine) - .226 hp / lb power ratio
*Ki-61-I-KAIc* was 7,650 lb loaded (with an 1,159 hp engine) - 0.15 hp / lb power ratio
*P-38L* was 17,500 lbs loaded (with two ,1600 hp horsepower engines) - 0.16 hp / lb power ratio
*P-47D-30* was 12,731 loaded (with a 2,600 hp engine) - 0.20 hp / lb power ratio
*P-51D* was 9,200 loaded (with a 1,490 hp engine) - 0.16 hp / lb power ratio but! The wiki also notes 1,720 hp at WEP for a much better 0.18 hp / lb

So the useful range for power-mass seems to be from 0.15 to 0.20 or better.

Now to compare with the P-39 and P-40. First note that the P-40 is on the lower end of the above list of fighters range in terms of weight, and the P-39 is lighter than all of the above accept the Ki-61.

P-39 at military power (1,200 hp) was at 0.16 power/mass but if you at that at rated "takeoff" power of 1325 it's 0.176 which is a bit better. I suspect they could boost that engine higher though at least at low altitude though I don't know how much.

P-40s are as follows

P-40B Tomahawk was 7,326 lbs loaded (with 1040 hp engine) for a power ratio of 0.16 which isn't great but isn't terrible either. It's as good as a Hellcat.
P-40E was 8,280 lbs loaded (with 1,150 hp engine) for a power ratio of 0.14. However WEP was 1,470 hp (56" Hg) which brings it to 0.17 which is pretty decent. Close to a Corsair.
P-40K was 8,500 lbs loaded (with a 1,325 hp engine) for a ratio of 0.155 but at WEP (1,550 hp at 60" Hg) it was 0.18 which is pretty good.
P-40F was 8,480 lbs loaded (with 1,300 hp engine) for a ratio of 0.15 but at WEP (1435 hp) it was 0.16
P-40L was 8,020 lbs loaded (with the same 1,300 hp engine) for 0.16 and 0.17 respectively.

So in a nutshell, the P-40s were right on the _edge_ of having sufficient power, you can see why they stripped some weight out when they could, and why they tinkered with the engines to get more speed out. If the overboosting stories are true and they really did go all of the way up to 1,700 hp tat would put a P-40K at a power ratio of 0.20 which is quite good. Also, compared to many fighters it faced in Europe, the P-40 had long range and carried a lot of fuel. By the time it reached a target on an escort or fighter sweep mission it would be lighter compared to enemy fighters taking off to attack them. Also the P-40 had very good dive speed and dive acceleration so experienced pilots could use that to keep it's speed up.

One other thing about the above list which is part of the issue I think with peoples opinions on certain planes - the same stats tend to get repeated over and over and as we know, Wikipedia isn't exactly superb in terms of signal to noise ratio or reliability. One of the specific issues on WW2 fighters is that they quote different types of numbers for engine horsepower and then provide all kinds of other stats behind that. So for example for one aircraft they show hp at 10,000 ft for another at sea level or for takeoff, for one they show military rating for another HP on boost. So you often aren't even comparing like with like.

P-40 and P-39 engines are often quoted at their takeoff or military power settings. Which makes them look even more underpowered. The Allison V-1710-39 on the P-40E is usually shown as giving 1,150 which is rated power at 45.5" Hg. But the WEP setting was later set at 56" (1,470 hp) and it was apparently routine to operate at 60" Hg (for 1,550 hp) which is a very big difference. It takes it from a dismal power ratio of 0.14 to a respectable 0.18. 

So maybe this aircraft is a bit of a dog up high, but an experienced pilot can get it moving pretty well at least down low which could come as a nasty surprise 

The extra HP was also apparently built into the strategy developed by the DAF from 1942 of "turning into the attack" meaning whole squadrons would wheel around and face diving enemy fighters. They really couldn't do this earlier before they "_*got our Kittyhawks running properly *_" to quote Bobby Gibbes. I don't think it was even an option in early 1942 when they were suffering much heavier losses.

Anyway, I know it's a big data dump, it's obviously something I'm quite interested in and would like to get right. Hope others may find it interesting.

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## wuzak (Dec 8, 2018)

Schweik said:


> So in a nutshell, the P-40s were right on the _edge_ of having sufficient power, you can see why they stripped some weight out when they could, and why they tinkered with the engines to get more speed out. If the overboosting stories are true and they really did go all of the way up to 1,700 hp tat would put a P-40K at a power ratio of 0.20 which is quite good. Also, compared to many fighters it faced in Europe, the P-40 had long range and carried a lot of fuel. By the time it reached a target on an escort or fighter sweep mission it would be lighter compared to enemy fighters taking off to attack them. Also the P-40 had very good dive speed and dive acceleration so experienced pilots could use that to keep it's speed up.



But at what altitude was that 1,700hp?

It's not much use having the best power-to-weight ratio at 0ft if it is quickly reduced to average, or worse, at the altitudes where it was expected to operate.

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## Schweik (Dec 8, 2018)

wuzak said:


> But at what altitude was that 1,700hp?
> 
> It's not much use having the best power-to-weight ratio at 0ft if it is quickly reduced to average, or worse, at the altitudes where it was expected to operate.



1700 hp is probably very far down indeed, right on the deck no doubt. Boosting that high was probably very rare I would assume. But that doesn't mean it's useless. Dogfights often devolved to lower level fighting. Both escapes and pursuits can end up "on the deck" and in such a circumstance, for an Axis pilot used to a certain level of performance that could come as a nasty surprise I think. Certainly the anecdotal descriptions of combat describe a lot of such long chases and also specifically P-40 pilots using dives to disengage which is really important in surviving air combat (assuming you don't die in the initial bounce).

However for the not quite as high but still boosted levels apparently that higher HP can still be reached at medium altitude. For example these charts of the famous 'stripped' (7900 lb) early P-40N with the V-1710-115 show that it was able to maintain 57" Hg boost up to 6800 feet and 50.5" up to 10,000 feet, and that was still providing enough power for a climb rate of 3,270 fpm at 7500 ft and 2,930 fpm at 10,000 ft. In a second test 'Critical full throttle height' was indicated at 9,200 feet with 57" Hg for 352 mph, and still doing 352 mph at 10,000' with 55.25" Hg so presumably that is getting a fair amount of horsepower though I know they couldn't actually measure that.

P-40 Performance Tests
http://www.wwiiaircraftperformance.org/P-40/A29-412-climb-WEP.jpg
http://www.wwiiaircraftperformance.org/P-40/A29-412-level-speed-WEP.jpg

At Sea Level 57" Hg means just about 1,500 hp according to my sources. I don't know what it means at 9,000 feet.

I think that early P-40N probably outperforms most or all of the earlier Allison engined P-40s anyway so it's a bit of an outlier.

Maybe not V-1650 powered P-40F or L though. Anyway it seems like they had some pretty high power available still at 10,000 feet. I would assume therefore they didn't have to dive down to the deck to get some extra power and performance, as at 8-10,000 feet they were already getting a fairly good head of steam at WEP. But if they got into real trouble conceivably they _could _dive down to get even more, for example when being chased back to their base as sometimes happened (as was apparently routine tactic of the RAF's Allison engined P-51s using the same engines) or when chasing enemy fighters which were trying to disengage

In the Med their job was often escorting medium bombers to attack German and Italian air bases. This served two purposes - it meant that the fight was taking place at around 10,000 feet or less, since that was the typical cruising altitude of the A-20's and B-25's, Baltimores etc. they were escorting from what I gather (later B-26's too) and it forced the Axis fighters to engage (if they wanted to stop the bombers) which put them at a disadvantage


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## P-39 Expert (Dec 9, 2018)

Schweik said:


> Interesting, well 1,325 hp is pretty good. WEP at low altitude is probably a bit better.
> 
> As for the weight issue, I"m not sure I buy that the P-39 and P-40 were overweight, but I think they were initially underpowered which is not quite the same thing. Almost every pilot agrees that P-40s were plenty maneuverable and had no problem pulling tight turns. The wing loading was pretty low at least by ETO / MTO standards. The engines weren't that powerful though for a heavier fighter.
> 
> ...


P-39 and P-40 were drastically overweight. Your figures for the FW190A-8 of .20HP/lb is 42% more than a P-40E of .14HP/lb. Meaning the FW190A-8 has 42% more horsepower per pound of weight. For a P-40E to have a .20HP/lb ratio meant the P-40E would need to weigh no more than 5750lb, meaning it would need to be 2530lb lighter. That's well over a ton.

The P-40 (and the P-39) were both drastically overweight. The P-39 could have been fixed (easily at airbase level) but I don't know how to make a P-40E lighter by 2530lb.


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## Schweik (Dec 9, 2018)

P-39 Expert said:


> P-39 and P-40 were drastically overweight. Your figures for the FW190A-8 of .20HP/lb is 42% more than a P-40E of .14HP/lb. Meaning the FW190A-8 has 42% more horsepower per pound of weight. For a P-40E to have a .20HP/lb ratio meant the P-40E would need to weigh no more than 5750lb, meaning it would need to be 2530lb lighter. That's well over a ton.
> 
> The P-40 (and the P-39) were both drastically overweight. The P-39 could have been fixed (easily at airbase level) but I don't know how to make a P-40E lighter by 2530lb.



I disagree - and I don't think you understood my point. 

First - the .14 hp/lb number is based on engine settings (45" Hg) which were not actually used in combat.

Second, sure the Fw 190 had an excellent power to weight ratio, it was well known as one of the fastest fighters of the war. It also incidentally made good use of it's very high weight to dive and pick up even more speed. That is why it had a much better combat speed than the Spit V. But that is really the only strength of the Fw 190. It couldn't turn with a Spitfire, or a P-40.

A Fw 190A-8 had a wing loading of 49.4 lb / square ft. Compare that to a P-40E with a hefty loaded weight of 8,280 lbs - it has a wing loading of 35.1 lb/square ft

What is the difference, really, between a P-40E and a Fw 190? The Fw is fifteen hundred pounds heavier, has smaller wings (34' span vs. 37') but it also has a (600 hp) more powerful engine. It's a drag racer. The P-40 though not as fast, is a Grand Prix racer, capable of making the tight turns. With a more powerful engine it can keep up.

The P-51, also 1,000 lbs heavier than a P-40, had a wing loading of 39 lbs / sq ft. We know that P-51s were on par in combat with Fw 190s, I think that is pretty well established. And yet the P-51 didn't have a super high power to weight ratio. What it did have was excellent streamlining, jet effect from it's exhaust, and (nominally) laminar flow wings, and 300 more horsepower. Which is why it's combat speed was so high.

If you read that post again, you'll notice that both the P-39 and the P-40 in most versions were actually on par in terms of power / weight with the P-51, (late model) P-38, F6F and Corsair, at least at the lower altitudes. Below 20,000 feet, a P-40L had almost as much power as a P-51D, it was still slower but it was also more maneuverable. In a combat with a Bf 109 or Fw 190 it could dive to pick up speed.

So if a P-40 or P-39 is overweight, so are all the other fighters I listed.

S


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## Schweik (Dec 9, 2018)

Also, for all it's excellent power to weight ratio, the Spit V had a theoretical top speed of 375 mph / 605 kph, the P-40F per this test, had a top speed of 370 mph so it's hardly lagging way behind. And while the Spit V was in many ways a better fighter, it wasn't in all ways.


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## P-39 Expert (Dec 9, 2018)

Schweik said:


> I disagree - and I don't think you understood my point.
> 
> First - the .14 hp/lb number is based on engine settings (45" Hg) which were not actually used in combat.
> 
> ...


The difference between a P-40E and a FW190 is 50mph and 1000fpm better climb at 20000'. I don't know how to put it any simpler.

The P-51(BCD) had a high combat speed because it had a two stage engine for high altitude performance. Neither the P-40 nor the FW190 had that.


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## Schweik (Dec 9, 2018)

P-39 Expert said:


> The difference between a P-40E and a FW190 is 50mph and 1000fpm better climb at 20000'. I don't know how to put it any simpler.



Sure, but what is the actual difference? Are you arguing that the Fw 190 was lighter? The only difference I can see was the engine, and perhaps drag (wingspan certainly) - but that is not the same thing as being overweight, the early P-40E was underpowered. But not all P-40s were.

To wit and more importantly the Fw 190 didn't face many P-40Es (maybe a few in RAF service) but it did face P-40K, P-40Fs, P-40Ls (which actually had a better rate of climb by the way) P-40M and P-40Ns, all of which had substantially more powerful engines than the E (or more precisely - engines which were used at much higher power settings and therefore delivered much more horsepower). And the combat record in particular for the US flown P-40F and L, is clear in that they were able to face enemy fighters on at least equal terms, including the Fw 190. The records published in Shores Volume IV make that quite clear.

The P-40 never did get an 1,800 hp engine but it had other strengths, maneuverability, dive speed etc.



> The P-51(BCD) had a high combat speed because it had a two stage engine for high altitude performance. Neither the P-40 nor the FW190 had that.



Yeah but it's not that simple because not all combat took place at 28,000 ft. In the Med, in Russia, in the Pacific and the CBI, a lot of the air combat took place at low altitude. This is a big part of why the P-39 did so well in Russia as we know. It's also why the P-40 was viable in those Theaters, as we now know and contrary to what is said in a lot of books printed in the 20th Century.

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## Schweik (Dec 9, 2018)

If the primary mission of the air forces is to say, sink landing craft (as at Sicily or Anzio.. or Milne Bay) or to blow up bridges, or destroy tanks (as say at El Alamein or Stalingrad or Kursk), then the fighting will take place at low altitude. *The fighters*, in other words,* go where the bombers are*. I don't get why this is so hard for people to understand. It should be particularly obvious for a P-39 enthusiast. There was almost no value on the Russian Front to flying fast at 25,000 feet. This is why the MiG 3 was a disappointment, it's why they didn't care for the P-47 for example, and it's why they liked the P-40 and loved the P-39.

So much analysis of WW2 seems to be based on bomber escorts in 1944 at 25,000 feet. And yet, by then the outcome of the war was already a foregone conclusion. The real struggle took place in 1940, 1941, 1942, and probably the first half of 1943. Of course many people died after that, especially civilians, but just because "Big Week" happened chronologically later than say, Tobruk, Guadalcanal or Kharkov, doesn't mean it was actually more important to the outcome of the war.

Certain Theaters like the Med, the CBI, and the Russian Front, and the Solomons tend to get vastly less emphasis in popular portrayals of WW2 in Anglo-American media than D-Day and the Ardennes Offensive. But I think modern historiography in general is increasingly recognizing the critical nature of the supply lines - Oil from the Middle East, oil in Southern Russia, every kind of supply in the Burma Road and so on, to creating the tipping point in the war. These were the most important fights during those critical middle years of the war.


And that is where you found the P-40 and the P-39, the Hurricane and the Spit V, the Wildcat and the Yak 1 bearing the brunt. They may not have flown over 400 mph at 30,000 feet but they shot down the enemy fighters, sunk the enemy ships and blew up the enemy tanks, and that is what actually mattered.

S

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## Glider (Dec 9, 2018)

A lot is being made of the claims and losses that are in the Vol 4 of thr Shores series. Mine is for Christmas so I have to wait a couple of weeks yet but other factors play into real life which are being ignored.
By this stage of the conflict the Germans were heavily outnumbered, spares, supplies and fuel very hard to come by. New pilots were not close to the calibre of the old one who would have been very tired.

As to performance the 190 was nearly always capable of 390 mph+ figures the P40 could only dream of, no matter what version, giving it a significant advantage. A lot is made of the occasional really good day the USAAF had but this the other factors mentioned above should also be remembered.
Had the positions been reversed and the P40's been heavily outnumbered, how do you think they would have fared?

I have never heard of any allied pilot who flew the P40 and the 190 or 109G who considered the P40 to be remotely as capable in air to air combat as the German aircraft 

During the Six day war there was a combat between the Jordanian Hunters and Israeli Mirage III's where the Hunters won, but would anyone seriously say the Hunter was an equally good fighter (and I have a really soft spot for the Hunter).


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## Schweik (Dec 9, 2018)

Glider said:


> A lot is being made of the claims and losses that are in the Vol 4 of thr Shores series. Mine is for Christmas so I have to wait a couple of weeks yet but other factors play into real life which are being ignored.
> By this stage of the conflict the Germans were heavily outnumbered, spares, supplies and fuel very hard to come by. New pilots were not close to the calibre of the old one who would have been very tired.



I will give this to you Strategically and Operationally but this was not usually the case Tactically. The Germans were pretty good at putting a large force together to challenge Allied formations. The days of 4 Bf 109s attacking 20 DAF fighters were long gone by 1943, largely due to the changing tactics of the latter (less purely defensive after mid 1942). So most of the fights were fairly even (20 vs 20, 40 vs 40) or sometimes tilted one way or the other but generally the Luftwaffe did not fight outnumbered - they concentrated their forces at the expense of abandoning other parts of the front which was a source of constant tension between them and the Afrika Korps. In Sicily and Italy etc. the front lines were smaller so this was less of an issue.

I will say this though as far as Fw 190s - a lot of the ones shot down over Italy etc. weren't really fighter units they were Jabo units often recruited from Stuka pilots and not given a lot of fighter training so that may account for some of how things went. I would not say the same generally for Bf 109, MC 205 or MC 202 pilots though at that stage (though the Italians in particular may have been suffering from bad morale). Luftwaffe pilot training was not yet so acute of a problem in early to mid 1943 as far as I know. Certainly no worse than pilot training had been for the Allies in 1941 and 1942!!! Does this "times were tough" argument not apply equally in both directions? How come it's never brought up to explain the glorious victories of Luftwaffe Experten in 1941 and early 1942 in Russia and the Med?



> As to performance the 190 was nearly always capable of 390 mph+ figures the P40 could only dream of, no matter what version, giving it a significant advantage. A lot is made of the occasional really good day the USAAF had but this the other factors mentioned above should also be remembered.



This seems to be the go-to implication on here when I have pointed out days when P-40s shot down more German or Italian fighters than they lost. But I have been looking for all the engagements and trying to count them up. In Volume II the RAF Kittyhawk pilots had plenty of bad days - the exceptions were especially from the dozen or so DAF pilots who became Aces. In Volume III the RAF still has quite a few bloody noses, but this was increasingly offset by days where they did well. Still probably 2 bad ones for 1 good one. 

The USAAF P-40 units, of which there were *5 Fighter Groups* had only five "bad days" that I found in Volume III, and only one really bad one (Feb 2 1943) and that was against Fw 190s. They had maybe 10 "good days" by contrast, about twice as many in other words.

In Volume IV so far, the worst "bad day" I found so far was 9 July 1943 where the 324th FG lost 3 P-40s in air to air combat with Bf 109s and another 2 allegedly to Flak - scoring no actual victories in spite of a bunch of claims. There are at least 4 days where they lost 1 or 2 fighters for no victories. But I have found 13 days where they came out ahead by at least 2-1 and often by as much as 5-0 or 6-1. Especially certain units (325 FG really stands out). In other words I have been counting all the combats, the only ones I filter out are the ones which 1) there were no major losses of P-40s and 2) the fighting was too busy to determine who shot down what. So for example if Spitfire pilots claimed 5 enemy planes and P-40 pilots also claimed 5, and the enemy actually lost 4, I can't tell you who shot which aircraft down and I know what the assumption would be. If a lot of P-40s were shot down I'll mark that page regardless but there don't seem to be too many of those. The majority of their losses were to Flak on days where they didn't even face opposition (and LW made no claims)

The ones which stand out are days where for example 325 FG was doing a sweep over Sardania and there were no other Allied claims in the area or at all on that day, so in those cases you can clearly see from the loss records who came out on top. 

*TL : DR* I don't think it is a fluke and I have not been cherry picking these dates. When you get your copy lets go through the whole thing and count it.



> Had the positions been reversed and the P40's been heavily outnumbered, how do you think they would have fared?



The answer is they were often outnumbered, and they usually fared well anyway. At least the USAAF units did.



> I have never heard of any allied pilot who flew the P40 and the 190 or 109G who considered the P40 to be remotely as capable in air to air combat as the German aircraft



This is a much higher threshold than before but I'll accept that challenge. I do know of a few. Will post quotes later.



> During the Six day war there was a combat between the Jordanian Hunters and Israeli Mirage III's where the Hunters won, but would anyone seriously say the Hunter was an equally good fighter (and I have a really soft spot for the Hunter).



I don't think it's a fair comparison - the P-40 wasn't A Hawker Hunter (or a Brewster Buffalo or an I-16 or an LaGG-3). P-40s had 2,225 overall victory claims in American service, and 592 in the Med, almost twice as many in the Med as US Spitfires (364), more than twice as many as US P-47 pilots scored in the Med (263) and vastly more than the P-39 (25). Add to that 450 claims by RAF / Commonwealth P-40 pilots in the Med and it's clear that it was not some fluke. Many discussions and descriptions of the P-40 including quite a few in other threads on this forum have claimed over and over again that a pilot flying a P-40 had zero chance in combat against a Bf 109, Mc 202, or Fw 190. However Shores books and by extension the actual historical records make it pretty clear that P-40 pilot shot down dozens of Bf 109s and MC 202s, and a small but significant number of MC 205s and Fw 190s. It's also worth pointing out that quite a few Experten were shot down


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## Stig1207 (Dec 10, 2018)

It's odd, but American sources seem to vary somewhat when it comes to claims and losses. Eg. looking at losses in the MTO in 1943 in this doc, the greater proportion of USAAF losses are attributed to enemy aircraft, not flak.

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## tomo pauk (Dec 10, 2018)

There is too much said here for me to try and answer all, so I'll just add my 2 cents worth.
P-40 in this forum mostly got a fair treatment - my take on it is that it was a decent fighter, with many qualities one can attribute to a specific type (strong, decent performance, usually well armed for the task, great rate of roll, can turn well), plus it's main attribute - it was mass produced in the dire hours of 1941-42, so it very much mattered for the Allied war effort.
The failings were that it's power/weight and power/drag (drag as a equivalent flat plate, or drag expressed in pounds, not drag coefficient) at altitude was sorely lacking. Lack of power at altitude is an attribute of V-1710, high weight was a result of size, fuel specification, G load specification and armament installed, drag was a result of size, wight profile & series, plus add-ons that add drag increments.
Lack of power at altitude is where it hurt the most. At 15000 ft (that already by 1940 was not regared as that a high altitude), V-1710-33, -39 and similar Allisons will make ~1030 HP, the Merlin XX, 45 and similar will make 1270 HP, DB 601N gave 1170+ HP, 601E made more than 601N. BMW 801C/D - 1340-1400 HP.
That would mean that power to weight ratios where low-altitude engine power is used is misleading, since most of airforces expected from their fighters to fight at all altitudes. Power/weight has almost no bearing to the max speed, we know that heavy P-40F was much faster than heaviest version of Hurricane II, and that heavy P-51 was much faster than light Spitfire when similar HP was available - drag was the issue, not weight. We also know that those British fighters climbed better than those US fighter due to being lighter.
The V-1710 was improved by late 1942 with 'upped' S/C drive, however other people moved on - British with 2-stage Merlin, Germans with DB 605 and fully-rated DB 601E and BMW 801D, meaning that P-40 was still unable to compete above 15000 ft. The newest V-1710 gained parity in altitude power with Merlin III and DB 601N - not a good result. The 2-stage V-1710 was also running late, and there was no 'big S/C' V-1710 version either. At the end, the P-63 got the 2-stage V-1710, the P-51 got the 2-stage V-1650, the P-40 didn't received any, apart from the too late prototypes.

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## Schweik (Dec 10, 2018)

Stig1207 said:


> It's odd, but American sources seem to vary somewhat when it comes to claims and losses. Eg. looking at losses in the MTO in 1943 in this doc, the greater proportion of USAAF losses are attributed to enemy aircraft, not flak.



Neat, thanks for posting that definitely going to save that document! To clarify I think there are two factors relevant here - first MAW volume IV covers (I think) May 1943 through September 1944. So half of 1943 and most of 1944. If you look at the document you posted AAA _is_ actually the leading cause of fighter losses for 1944 (441 to enemy aircraft, 493 to flak).

In 1943 you are right it looks like a lot more fighter losses were to air combat (816 to 115, plus 157 to "other causes") but I suspect this is mainly the various other fighters - namely P-38s (which seem to have taken heavy casualties), Spitfires, Beaufighters, P-39s, and P-47s and then P-40s. Two of the main P-40 units (325 FG and 57 FG for a total of six squadrons) converted over to P-47s roughly in the late summer of 1943. That left three P-40 FG's in the USAAF - the 79th, 33rd and 324th. I believe the 79th also transitioned to P-47s in mid or late 1944 though I'm not certain. I know they were still flying P-40s at Anzio in early 1944.

I assume A-36s were counted as light bombers on your list but I'm not sure.

Anyway I have only skimmed the book so far and have not done a precise count yet, but I may pick a month and do a count of all claims and losses on that time span to further clarify the picture so to speak, as I did previously for a month in MAW III. What I'm saying at this point is based on my impressions from briefly looking at the total claims and losses on every page a couple of times. To repeat, the US P-40 fighter groups did not generally suffer a lot of losses in Volume IV, but the losses they did suffer seemed to be mostly flak or ground fire and also engine failure and other mechanical problems. Same for the P-47s. They were both flying a lot of the low to medium altitude missions (even though P-47s would have been better at high altitude missions!) while the P-38s were flying escort for the heavy bombers and the US and RAF Spitfire squadrons were facing the brunt of the air superiority fight from around August 1943 onward.

However it is worth noting that P-40 squadrons were still flying fighter sweep and (medium) bomber escort missions (usually _without_ any top cover from Spitfires or P-38s contrary to legend) through the end of 1943 and they clearly were not getting slaughtered. The 57th FG was a bit of a hybrid in mid 1943 though as they had both P-47s and P-40s flying together for a while.

One reason why the 325th FG in particular may have done so well in comparison to the others is that it was attached to a bomb group (of 3 B-26 squadrons) and therefore was flying mostly medium altitude bomber escort and fighter sweep missions, whereas the other Fighter Groups like the 324th and all the RAF squadrons were flying a lot of ground attack and CAS missions which were much more dangerous both in terms of flak and enemy fighters.

S


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## Schweik (Dec 10, 2018)

tomo pauk said:


> There is too much said here for me to try and answer all, so I'll just add my 2 cents worth.
> P-40 in this forum mostly got a fair treatment - my take on it is that it was a decent fighter, with many qualities one can attribute to a specific type (strong, decent performance, usually well armed for the task, great rate of roll, can turn well), plus it's main attribute - it was mass produced in the dire hours of 1941-42, so it very much mattered for the Allied war effort.
> The failings were that it's power/weight and power/drag (drag as a equivalent flat plate, or drag expressed in pounds, not drag coefficient) at altitude was sorely lacking.




I can't really disagree with any of that. The P-40 in all it's forms was severely limited by it's altitude performance. In fact I'd take it a step further to point out that the real "performance ceiling" was not always at 15-16,000 feet as is often mentioned, but for the low-geared Allisons on the P-40E and P-40K, it was really more like 12,000 feet. Which is certainly a _major_ hindrance to performance. This is the reason IMO that the USAAF almost exclusively used the merlin XX engined P-40F / L instead of the other types for the Med, even though for example the P-40K was considered much faster down low ... because the P-40F / L had that 20k' performance ceiling which meant they were not getting jumped from above so often. In the Pacific and CBI the dive speed advantage of the P-40 was so significant, once they learned to correctly use it, that it was sufficient to correct for the altitude defect.

I also agree with you that drag was an issue related to speed- often mentioned by the Russians for example since the P-40 was much draggier than most of their native made fighters and, I think significantly, much more draggy than a P-39. But weight was more important, as you noted, for rate of climb which also mattered a lot for combat speed. Significantly, one of the things I learned about the P-40 doing research was that the jump up to WEP made a change in rate of climb from a miserable 2,000 fpm or even less to over 3,000 fpm. I have pilot accounts noting that they had to climb to altitude using WEP. This is why I think engine power was such an important issue for the design.

So granted -* the performance ceiling was a major flaw of the P-40.*

However, many good fighters in WW2 did have a significant flaw or three. Being a medium to low altitude fighter was not necessarily a fatal flaw. In fact we know that almost all the Russian made fighters were low altitude planes, the RAF specifically designed certain versions of the Spitfire to fly at low altitude (LF versions) and fielded the troubled but ultimately successful Typhoon and Tempest series which were basically low altitude birds and so on. It could actually be a useful thing to have for certain Theaters or certain operations.

My point is that P-40s were clearly a bit more important than we had assumed. More than I had assumed anyway. There are hundreds of books which faithfully repeat the Trope that the P-40 was "rugged but unmaneuverable and slow". Many P-40 pilots repeated that they liked the plane because "it would get you home" - partly a factor of strength in the build etc. and that is how the legend about the plane attributed it. But we here in this forum know that no amount of armor or extra longerons can protect an aircraft from being disintegrated under sustained 20mm cannon fire. The P-40 got it's pilots home because of the combination of being 'rugged' with being very maneuverable (roll and turn) and fast in a dive, meaning it gave pilots the all-important ability to _disengage_. I think that is one of the key factors that gets forgotten in discussions of fighters.

The fact that so many P-40 pilots were Aces, and that P-40 pilots at least claimed more enemy aircraft (2225 in US service alone) shot down than F4F or F4U pilots (not even counting RAF and Soviet claims), and were in fact able to hold their own against Bf109s and MC 202s routinely - and all the way into 1944, was all news to me. And that I think probably needs to be corrected in the shorthand on the history of this aircraft. Everybody knows about the AVG but that tends to be treated as a one-off, and even diminished (they were supposedly only fighting Ki-27s etc.).

Yes it was a deeply flawed design, but they seem to have found ways to work around that flaw and experienced, well trained pilots were able to really do a lot with it. It had a lot more capability than most people realize. In particular for Americans, the record of the US P-40 units in the Med seems to be very little known. They did more than shoot down Ju-52s!

And per the thread title, so apparently did the P-39 though it was mostly the Russians who were able to make the most of it.

S


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## Schweik (Dec 10, 2018)

I'm also going to go out on a limb with kind of a hunch, but from what I have seen so far I think if you crunch the numbers it's going to turn out that some P-40 units in the Med had significantly better claim / verified claim / to loss ratios than any of the P-38 or P-47 equipped units. And I think it will be close on the US Spitfire units as well. It would be a bit of work to prove this but I think that would go a long way toward correcting the record.


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## tomo pauk (Dec 10, 2018)

Schweik said:


> ... because the P-40F / L had that 20k' performance ceiling which meant they were not getting jumped from above so often. In the Pacific and CBI the dive speed advantage of the P-40 was so significant, once they learned to correctly use it, that it was sufficient to correct for the altitude defect.



P-40s were faster than most of Ki-43s and all Ki-27s, especiall the early P-40s. Even the Zero was not faster at any altitude.



> ...
> However, many good fighters in WW2 did have a significant flaw or three. Being a medium to low altitude fighter was not necessarily a fatal flaw.
> ...



Certainly not a fatal flaw, but it means that one has to have other fighters to fight at higher altitudes. Meaning that vast majority of P-40s were useless as escorts for B-17s or B-24s at their best altitude bands, as well as ill suited to intercept Axis bomber sorties that flew many times at 20000 ft - a problem shared with P-39s of 1942.



> Yes it was a deeply flawed design, but they seem to have found ways to work around that flaw and experienced, well trained pilots were able to really do a lot with it. It had a lot more capability than most people realize.
> ...



P-40 was not a deeply flawed design. We know that with a 2-stage V-1710 it went as good as the Fw 190D-9 or best performing Fw 190A. As good or better than any Italian, Soviet or Japanese fighter. The early versions were about as fast as Spitfire I/II, Bf 109E or Zero, while roll rate was far better, with capacity to carry sizable fuel quantity, firepower and protection.
Crucial problem was the too late introduction of considerably better engines, unlike what happened with Bf 109, Spitfire, P-51 or later Italian fighters.


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## Schweik (Dec 10, 2018)

tomo pauk said:


> P-40s were faster than most of Ki-43s and all Ki-27s, especiall the early P-40s. Even the Zero was not faster at any altitude.



I have seen different numbers on this depending on the specific version(s) involved and in the case of the P-40E, what engine settings were used. There is a wartime test on WW2Aircraftperformance.org where a P-40K was able to extend from a Zero in level flight though some people have suggested they were using the wrong fuel for the Zero or that it had engine trouble. As far as I'm concerned I don't know enough to say that the Zero wasn't faster at _any_ altitude. It could definitely outclimb the P-40 at any altitude. But clearly the P-40 could pick up enough speed in a few minutes of diving to evade and disengage, which quickly became the standard practice in the Pacific and CBI.



> Certainly not a fatal flaw, but it means that one has to have other fighters to fight at higher altitudes. Meaning that vast majority of P-40s were useless as escorts for B-17s or B-24s at their best altitude bands, as well as ill suited to intercept Axis bomber sorties that flew many times at 20000 ft - a problem shared with P-39s of 1942.



I agree with this for the most part, but how important were B-17s and B-24s to the overall war effort in 1942? Or even 1943?

This is a larger / separate discussion but I think peoples attitudes about these fighters can partly hinge on whether they think air battles in 1944 or 1945 were the most important or the ones in 1942 / 1943 or the ones in 1940 / 41. I tend to lean toward the early and middle parts of the war as being the most important, which is probably part of the reason why I like the P-40.

I think one reason why the P-40 was disliked so much by generals during the war was due to what they call the "Bomber Mafia" faction in the Army Air Force. You are certainly right, the P-40 was not a good escort for B-17s or B-24s. Generally, I do consider the altitude limitation a major problem but they were also able clearly to work around it. P-40s did not have a problem shooting down G4M "Betty", Ki 21 "Sally", (at 20,000 feet or any other altitude) or B5N "Kate" or D3A "Val" bombers in the Pacific and CBI Theaters, regardless of the altitude limitations ( the inflammability of the bombers and heavy firepower of the P-40 seemed to compensate) and in the Theaters where it operated - Pacific, CBI, Med / Middle East and Russia, the most important bombing was going on down near sea level, focused on the destruction of ships, airfields, artillery, bridges and tanks in other words. For this part of the fight the P-40 was pretty well suited.

Not ideal though especially in Russia or the Med as they generally had to cope with being attacked from above by fast German fighters in particular and that is why I say it was 'deeply flawed'. I do see it as a major problem but also one they adapted to with special tactics.



> P-40 was not a deeply flawed design. We know that with a 2-stage V-1710 it went as good as the Fw 190D-9 or best performing Fw 190A. As good or better than any Italian, Soviet or Japanese fighter. The early versions were about as fast as Spitfire I/II, Bf 109E or Zero, while roll rate was far better, with capacity to carry sizable fuel quantity, firepower and protection.
> Crucial problem was the too late introduction of considerably better engines, unlike what happened with Bf 109, Spitfire, P-51 or later Italian fighters.



I agree with that but when I say the design was deeply flawed I meant _with_ the engines it actually had in combat during the war, i.e. with the inherent altitude limitation / performance ceiling. Of course people seem to forget that many other fighters also had altitude limitations (including notably the A6M and the earlier Fw 190s). Contrary to the myth, P-40 units were able to adapt to this flaw and operated without overhead cover from other fighters. They worked out effective tactics for attacking enemy fighters that were attacking _them_ from above, but it was never a comfortable proposition for pilots to have to give up the initiative like that and face what was always a kind of roll of the dice in the opening moments of a fight. If they could catch enemy fighters at co-altitude or below, they seem to have had a field day. It is too bad they never put a two stage engine in a wartime P-40 but from what I gather that may not even have been possible, I don't know. Anyway it didn't happen and I'm really focused here on the history.

S


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## tomo pauk (Dec 10, 2018)

Schweik said:


> I have seen different numbers on this depending on the specific version(s) involved and in the case of the P-40E, what engine settings were used. There is a wartime test on WW2Aircraftperformance.org where a P-40K was able to extend from a Zero in level flight though some people have suggested they were using the wrong fuel for the Zero or that it had engine trouble. As far as I'm concerned I don't know enough to say that the Zero wasn't faster at _any_ altitude. It could definitely outclimb the P-40 at any altitude. But clearly the P-40 could pick up enough speed in a few minutes of diving to evade and disengage, which quickly became the standard practice in the Pacific and CBI.



The P-40K will out-pace the Zero under 10000 ft or thereabout, with both A/C using best avaiable power.
Diving to disenagege is all good and well, however that will meant that enemy bomber just received a respite, or that allied bomber is without protection now.



> I agree with this for the most part, but how important were B-17s and B-24s to the overall war effort in 1942? Or even 1943?
> 
> This is a larger / separate discussion but I think peoples attitudes about these fighters can partly hinge on whether they think air battles in 1944 or 1945 were the most important or the ones in 1942 / 1943 or the ones in 1940 / 41. I tend to lean toward the early and middle parts of the war as being the most important, which is probably part of the reason why I like the P-40.



Heavies were certainly flying thousands of sorties in 1943, and even in 1942. They provided a way to hit Germany proper well before it was possible by more convetional forces, like artillery or infantry.



> I think one reason why the P-40 was disliked so much by generals during the war was due to what they call the "Bomber Mafia" faction in the Army Air Force. You are certainly right, the P-40 was not a good escort for B-17s or B-24s. Generally, I do consider the altitude limitation a major problem but they were also able clearly to work around it. P-40s did not have a problem shooting down G4M "Betty", Ki 21 "Sally", (at 20,000 feet or any other altitude) or B5N "Kate" or D3A "Val" bombers in the Pacific and CBI Theaters, regardless of the altitude limitations ( the inflammability of the bombers and heavy firepower of the P-40 seemed to compensate) and in the Theaters where it operated - Pacific, CBI, Med / Middle East and Russia, the most important bombing was going on down near sea level, focused on the destruction of ships, airfields, artillery, bridges and tanks in other words. For this part of the fight the P-40 was pretty well suited.



P-40 did it's part within the Allied war effort, no doubt about it. 'Bomber mafia' probably didn't wanted any fighter to steal the funds or glory.



> Not ideal though especially in Russia or the Med as they generally had to cope with being attacked from above by fast German fighters in particular and that is why I say it was 'deeply flawed'. I do see it as a major problem but also one they adapted to with special tactics.



Herelein lies the rub - in raw performance, and above 12000-15000 ft, P-40s were second to German fighters, and second to MC.202 actually.



> I agree with that but when I say the design was deeply flawed I meant _with_ the engines it actually had in combat during the war, i.e. with the inherent altitude limitation / performance ceiling. Of course people seem to forget that many other fighters also had altitude limitations (including notably the A6M and the earlier Fw 190s). Contrary to the myth, P-40 units were able to adapt to this flaw and operated without overhead cover from other fighters. They worked out effective tactics for attacking enemy fighters that were attacking _them_ from above, but it was never a comfortable proposition for pilots to have to give up the initiative like that and face what was always a kind of roll of the dice in the opening moments of a fight. If they could catch enemy fighters at co-altitude or below, they seem to have had a field day. It is too bad they never put a two stage engine in a wartime P-40 but from what I gather that may not even have been possible, I don't know. Anyway it didn't happen and I'm really focused here on the history.
> 
> S



Early Fw 190s were excellent at altitude (much better than late Fw 190s with BMW engines), only bested by Bf 109 of the era. The Spitfire VII/VIII/XI equaled them from late 1942 on, and Merlin Mustang and P-47 bested them above 20000 ft by some time of 1943.
Thee 2-stage engine was installed in handful of test P-40 in 1944 (= too late) - test report of one of those.


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## Schweik (Dec 10, 2018)

tomo pauk said:


> The P-40K will out-pace the Zero under 10000 ft or thereabout, with both A/C using best avaiable power.
> Diving to disenagege is all good and well, however that will meant that enemy bomber just received a respite, or that allied bomber is without protection now.



Yes, it's basically the same problem faced by Bf 109s against most Allied planes, they could attack from advantage and disengage but couldn't remain in sustained dogfights without increasing risk. Against Spitfires this more or less equaled out, against Soviet fighters at least initially they did very well.

From what I understand US P-40 squadrons in the Pacific and CBI dealt with this by breaking up into flights of four. So for example when attacking bombers, each flight would attack and then disengage when they got into trouble, but then another flight would attack and so on. The first flight to disengage would return to altitude by the time the third or fourth flight was engaging. In this manner they kept the Japanese fighters occupied and were able to maintain steady pressure on the bombers.

They could not use these kinds of tactics in the Med because German fighters, faster, very well coordinated and able to attack from above, could gang up on them. So in the Med they kept to large flights, whole squadrons of ~12 aircraft basically. Fortunately for the Allies in that Theater German bombers mostly operated at low or medium altitude because they couldn't really hit anything that mattered from ~20,000 ft.

Interestingly according to Australian pilots that served in both Theaters, while they were able to use their radios freely in the Pacific they had to be much more circumspect and disciplined about using them in the Med because Germans were able to determine their position.



> Heavies were certainly flying thousands of sorties in 1943, and even in 1942. They provided a way to hit Germany proper well before it was possible by more conventional forces, like artillery or infantry.



Well this is another argument isn't it? With the possible exception of the Ploesti raid I would argue that the heavy bomber raids were basically an attritional Strategy and did not play a significant role in any of the key turning points or battles of the war - especially before 1944. At Midway, Guadalcanal, El Alamein, Kasserine Pass, Tobruk, Sicily, Moscow, Leningrad, Stalingrad, Kursk, Kharkov etc. it was the tactical bombing and dogfights at low altitude that matttered.



> P-40 did it's part within the Allied war effort, no doubt about it. 'Bomber mafia' probably didn't wanted any fighter to steal the funds or glory.


 Especially one that was ineffective at escorting heavy bombers.



> Herelein lies the rub - in raw performance, and above 12000-15000 ft, P-40s were second to German fighters, and second to MC.202 actually.



Well the stripped P-40F and P-40L were pretty close I think up to 20,000 feet. Regardless, I can point to numerous days when they shot down Bf 109s, MC. 202 and MC.205 fighters at rates like 3-1 and a few at 6-1. So the raw performance didn't matter as much as we might think, at least in those battles.



> Early Fw 190s were excellent at altitude (much better than late Fw 190s with BMW engines), only bested by Bf 109 of the era. The Spitfire VII/VIII/XI equaled them from late 1942 on, and Merlin Mustang and P-47 bested them above 20000 ft by some time of 1943.



What was the engine before the BMW?



> Thee 2-stage engine was installed in handful of test P-40 in 1944 (= too late) - test report of one of those.



Yes that is P-40Q right? Promising but doomed by the crash of a couple of prototypes and overall (well earned) disfavor of Curtiss Aircraft company. It did look good but it didn't have the range or speed of the P-51 and I think that is what they cared about most at that point.

S


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## Stig1207 (Dec 11, 2018)

Schweik said:


> Neat, thanks for posting that definitely going to save that document! To clarify I think there are two factors relevant here - first MAW volume IV covers (I think) May 1943 through September 1944. So half of 1943 and most of 1944. If you look at the document you posted AAA _is_ actually the leading cause of fighter losses for 1944 (441 to enemy aircraft, 493 to flak).



Actually the leading cause of fighter losses in 1944 is 'other causes' = 637. 
MAW II, III, and IV together cover 1943, but I predict that crunching the numbers in these volumes won't get you a match with the figures from the document, which is from this: 
USAAF Statistical Digest .

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## P-39 Expert (Dec 11, 2018)

Schweik said:


> Yes, it's basically the same problem faced by Bf 109s against most Allied planes, they could attack from advantage and disengage but couldn't remain in sustained dogfights without increasing risk. Against Spitfires this more or less equaled out, against Soviet fighters at least initially they did very well.
> 
> From what I understand US P-40 squadrons in the Pacific and CBI dealt with this by breaking up into flights of four. So for example when attacking bombers, each flight would attack and then disengage when they got into trouble, but then another flight would attack and so on. The first flight to disengage would return to altitude by the time the third or fourth flight was engaging. In this manner they kept the Japanese fighters occupied and were able to maintain steady pressure on the bombers.
> 
> ...


The P-40E's main problem was it's combat ceiling was under 20000'. It was at a disadvantage against almost all other first line combat planes due to it's extremely heavy weight compared to it's engine power.

The mechanical two stage Allison was in production from May '43 and would have made both the P-40 and P-39 (and the P-51A) into great high altitude fighters. This engine eventually went into the P-63, a bigger and heavier version of the P-39 from late '43.


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## wuzak (Dec 11, 2018)

Schweik said:


> However, many good fighters in WW2 did have a significant flaw or three. Being a medium to low altitude fighter was not necessarily a fatal flaw. In fact we know that almost all the Russian made fighters were low altitude planes, the RAF specifically designed certain versions of the Spitfire to fly at low altitude (LF versions) and fielded the troubled but ultimately successful Typhoon and Tempest series which were basically low altitude birds and so on. It could actually be a useful thing to have for certain Theaters or certain operations.



The LF versions of the IX and VIII used the Merlin 66, which had the same ratings as the V-1650-7 used in later P-51Bs and P-51Ds. Low altitude was a relative term.

The LF.Vs were, as I understand it, retrospectively given the the LF designation. They were not designed as low altitude fighters, but were modified to be - specifically to combat the Fw 190A.

The XII was a low altitude fighter because it used a single stage Griffon, as those were the only ones available at the time.


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## Schweik (Dec 11, 2018)

P-39 Expert said:


> The P-40E's main problem was it's combat ceiling was under 20000'. It was at a disadvantage against almost all other first line combat planes due to it's extremely heavy weight compared to it's engine power.



But that isn't actually true. You didn't understand what you have been reading. Performance, especially climb, fell off starting at 12,000 ' and climb rate was no doubt very bad by 20,000', but that was not the ceiling. They routinely intercepted enemy bombers flying much higher than that. You should read this article which I posted previously, about the use of P-40s in the defense of Darwin. From March to September 1942, Japanese records confirm that novice P-40E pilots from the 49th FG were able to shoot down 12 "Betty" bombers flying at 27,000' in spite of a heavy escort of A6M2s so not only were they able to fly that high, they were fairly effective in combat (albeit with heavy losses of their own) .

Quote from the article:

_"Darwin’s 3.7-inch anti-aircraft artillery forced the G4Ms to ingress at high levels—generally between 25,000 to 27,000 feet. Such a high ingress altitude sorely tested the P-40E fighters as their Allison V-1710 engines suffered from an inadequate mechanically driven supercharger. The Allison, while rugged and reliable, lost considerable power at the higher altitudes, with the operational ceiling of the P-40E limited to around 27,000 to 28,000 feet."_

In fact the only US fighters I'm aware of which were literally unable to attack high flying bombers during the war were P-39s / P-400s' over Guadalcanal and that was apparently due to a lack of suitable oxygen equipment. P-39s were also active at Darwin but I don't know of any stats on their use there, do you?

The Darwin campaign was an early experiment, efficiency got much better. AVG and later 23rd FG etc. were routinely shooting down high flying Japanese bombers all through the war with P-40E, K and later N with minimal and diminishing losses.

S


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## Schweik (Dec 11, 2018)

wuzak said:


> The LF versions of the IX and VIII used the Merlin 66, which had the same ratings as the V-1650-7 used in later P-51Bs and P-51Ds. Low altitude was a relative term.
> 
> The LF.Vs were, as I understand it, retrospectively given the the LF designation. They were not designed as low altitude fighters, but were modified to be - specifically to combat the Fw 190A.
> 
> The XII was a low altitude fighter because it used a single stage Griffon, as those were the only ones available at the time.



Yes but lets be real the LF Spit Mk V, many regular Spit V, recon Spit IV and various others were using other specifically low altitude optimized Merlin engines like the Merlin 45, 45M, 50, 50M etc. some of which had cropped impellers specifically for low altitude power. For example Merlin 45M had a critical altitude of 2,750 ft (838 m) where it gave 1585 hp. Interestingly this is about the equivalent of the P-40K (which the English liked quite a bit) at normal / sanctioned WEP settings.

The short version of this is that they did perceive a need for low altitude fighters optimized to perform down where the Stukas were dropping their bombs.

I'm not an expert on the Rolls Royce engines, the Merlin or the Spitfire so I'm going mainly off of this:

List of Rolls-Royce Merlin variants - Wikipedia

S


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## Schweik (Dec 11, 2018)

Stig1207 said:


> Actually the leading cause of fighter losses in 1944 is 'other causes' = 637.
> MAW II, III, and IV together cover 1943, but I predict that crunching the numbers in these volumes won't get you a match with the figures from the document, which is from this:
> USAAF Statistical Digest .



Why would you predict that? Are you suggesting Shores numbers are off?

I will do some number crunching on one of the months, maybe July or June 1943 and we can see how it adds up. I'll post it in the P-40 vs 109 thread and then link back to here.


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## varsity07840 (Dec 11, 2018)

Schweik said:


> But that isn't actually true. You didn't understand what you have been reading. Performance, especially climb, fell off starting at 12,000 ' and climb rate was no doubt very bad by 20,000', but that was not the ceiling. They routinely intercepted enemy bombers flying much higher than that. You should read this article which I posted previously, about the use of P-40s in the defense of Darwin. From March to September 1942, Japanese records confirm that novice P-40E pilots from the 49th FG were able to shoot down 12 "Betty" bombers flying at 27,000' in spite of a heavy escort of A6M2s so not only were they able to fly that high, they were fairly effective in combat (albeit with heavy losses of their own) .
> 
> Quote from the article:
> 
> ...


There were no P-39s at Darwin. While oxygen was a problem with P-400s at Guadalcanal, P-39s did not have that problem. The record of P-400s and P-39s attempting to intercept bombers in New Guinea was poor at best. They were constantly bounced from above by escorting A6Ms. They did not have enough early warning time to get to altitude. AVG and 23rd FG P-40s benefited from adequate early warning as did Darwin P-40s, though perhaps to a lesser extant. P-40s in Java had no such luxury. The use of the P-39 and P-40 is a lesson in how US fighters were thrust into jobs that they were not intended for. They were not interceptors. The P-38 was an interceptor but forced into the high altitude escort role, among others where it did not excel.

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## Stig1207 (Dec 11, 2018)

Schweik said:


> Why would you predict that? Are you suggesting Shores numbers are off?
> 
> I will do some number crunching on one of the months, maybe July or June 1943 and we can see how it adds up. I'll post it in the P-40 vs 109 thread and then link back to here.



The USAAF stats certainly seem to portray a different picture than MAW does, for 1943 at any rate; with some 75% of USAAF fighter losses attributed to enemy aircraft according to the stats, just 11% to flak. As you yourself have remarked, in MAW fighter losses to flak are higher than that. Which numbers are off, I don't know, and I much prefer to think that there is a plausible explanation for why there is such a difference.

I agree on taking a single month or two and comparing the numbers, it's the way to go ; it will be interesting to see how it turns out.


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## fubar57 (Dec 11, 2018)

Stig1207 said:


> Actually the leading cause of fighter losses in 1944 is 'other causes' = 637.
> MAW II, III, and IV together cover 1943, but I predict that crunching the numbers in these volumes won't get you a match with the figures from the document, which is from this:
> USAAF Statistical Digest .


Thanks for the PDF


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## tomo pauk (Dec 11, 2018)

Schweik said:


> Yes but lets be real the LF Spit Mk V, many regular Spit V, recon Spit IV and various others were using other specifically low altitude optimized Merlin engines like the Merlin 45, 45M, 50, 50M etc. some of which had cropped impellers specifically for low altitude power. For example Merlin 45M had a critical altitude of 2,750 ft (838 m) where it gave 1585 hp. Interestingly this is about the equivalent of the P-40K (which the English liked quite a bit) at normal / sanctioned WEP settings.
> 
> The short version of this is that they did perceive a need for low altitude fighters optimized to perform down where the Stukas were dropping their bombs.
> 
> ...



By the time the 'cropped' superchargers were in use, the threat of Stukas was not present. Main threat/target were Fw 190s now (ie. early 1942 on).
The Merlin 45 and 50 were 'normal' versions, with impeller diameter of 10.25 in. The 45M and 50M were the ones with cropped S/C (dia of 9.50 in - same as 'ordinary' V-1710s), so gains in low altitude were traded for loss of hi-alt power.





The Merlin 30, 32 and 34 were also low-level engines, sporting small impeller (9.75 in diameter) and other modifications:

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## Shortround6 (Dec 11, 2018)

Schweik said:


> But that isn't actually true. You didn't understand what you have been reading. Performance, especially climb, fell off starting at 12,000 ' and climb rate was no doubt very bad by 20,000', but that was not the ceiling. They routinely intercepted enemy bombers flying much higher than that. You should read this article which I posted previously, about the use of P-40s in the defense of Darwin. From March to September 1942, Japanese records confirm that novice P-40E pilots from the 49th FG were able to shoot down 12 "Betty" bombers flying at 27,000' in spite of a heavy escort of A6M2s so not only were they able to fly that high, they were fairly effective in combat (albeit with heavy losses of their own) .



There is the "book" ceiling (service ceiling) at which a plane can still climb at 100ft per minute ( or a metric equivalent). rarely quoted is an operational ceiling, figured by the British for example as 500fpm of climb which allows a _formation_ of aircraft to maneuver and maintain formation (assume worst plane in the squadron is on the outside of a turn) and there is the COMBAT ceiling, generally around 1000fpm of climb which allows the plane to perform combat maneuvers without excessive loss of altitude. Obviously the last is the most subjective and nobodies aircraft could perform hard turns or part loops or other high energy consuming maneuvers in succession without losing altitude. 

Given _enough_ time/warning a formation of P-40s could climb to intercept height and execute an attack run (or more than one) on a formation of bombers. Dog fighting the escorting Zeros was pretty much out of the question. Shoot at them if they were in front of you but otherwise, get in/get out turn around at a safe distance and repeat. trying to do much more than roll the P-40 form one side to the other and gentile snake turns was going to result in a large loss of altitude that would take minutes to recover from. A P-40 might take 6 minutes or more to climb from 24,000ft to 28,000ft depending on weight or air temp/pressure and that is at best climb speed, once at desired altitude it still has to accelerate to combat speed. 

Depending on such a fighter to intercept attacking bombers is not a good choice if other fighters are available. 




> The Darwin campaign was an early experiment, efficiency got much better. AVG and later 23rd FG etc. were routinely shooting down high flying Japanese bombers all through the war with P-40E, K and later N with minimal and diminishing losses.



The P-40N had the later engine and all ceilings are raised by 3-4000 ft. 
Stripping weight (pretty much guns, ammo and fuel) could also improve the performance of fighters in the field. 


The P-40E was overweight, there is no" if, and or but" about it. The six .50 cal weapons installation was simply too heavy for the engine available. about 900lbs of guns and ammo which is several hundreds more than guns/ammo in a Spitfire V/IX or most of the the 1941-42 single engine fighters. It may be more than the FW 190. it may be triple what some of the Italian and Japanese fighters were carrying for armament. 

Unfortunately once you design the plane around such a weapons load you can't go back to "zero" by simply taking out a pair of guns in the field and not filling up the ammo bins. 
The P-40 gained around 300lbs of weight in the wing structure from the initial P-36 wing to the late model P-40 wings. If you want to keep the 8 "G" service rating (12 "G" ultimate load) you have to beef up the structure as the gross weight increases. Likewise weight of the landing gear/tires and even the fuselage may have to increase slightly to handle the higher weights. You are stuck with those wight increases in the field no matter what you do with the guns/ammo/armor. 

Lets also remember that the P40D/E was _ordered _in the spring-summer of 1940, *before the Battle of Britain. *



Design and performance estimates have to looked at in that light and not as much what it was faced with in combat in late 1941 (British and Soviet ? use) and 1942 against the Japanese. Please note the P-40F prototype flew in the summer of 1941 around 6 months before Pearl Harbor so the US was not ignoring the lack of altitude capability of the P-40.

I would also note that the P-40D/E was initially rated with a combat load of 120 US gallons of gas. You could put an additional 28 US gallons in the rear fuselage tank but you basically had a 8100lb airplane with just that 120 US gallons of fuel and 1150hp engine (the WEP ratings are totally irrelevant at this point as at the time of the order/s and finish design work the older Hawk 81s {tomahawks and P-40B/C} had not entered active service let alone combat so there was NO unofficial combat boosting going on of the older engine let alone anything base overboosting of the new -39 engine on.)

It shouldn't have taken a degree in astrophysics to figure out the power to weight ratio wasn't going to be good to good. In defence in the summer of 1940 nobody else (except the the British ) had supercharger much better than the one on the Allison _in service._

Back to the weight thing. As a very rough estimate you can figure that the payload of plane (for a fighter guns/ammo/fuel/pilot etc) as 30% (or somewhere between 25-35% ) of the gross weight of plane in the initial design stage. You want to add 20-30% to the payload you need a plane that grosses 20-30% more to keep everything else (field length, stalling speed/turn etc) the same. But once you make the wings/fuselage/landing gear bigger and heavier to handle the higher payload you don't get all the performance back by not putting the full the payload into the larger aircraft.


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## Shortround6 (Dec 11, 2018)

Schweik said:


> Yes but lets be real the LF Spit Mk V, many regular Spit V, recon Spit IV and various others were using other specifically low altitude optimized Merlin engines like the Merlin 45, 45M, 50, 50M etc. some of which had cropped impellers specifically for low altitude power. For example Merlin 45M had a critical altitude of 2,750 ft (838 m) where it gave 1585 hp. Interestingly this is about the equivalent of the P-40K (which the English liked quite a bit) at normal / sanctioned WEP settings.
> 
> The short version of this is that they did perceive a need for low altitude fighters optimized to perform down where the Stukas were dropping their bombs.
> 
> ...




we have several confusing things going on here. we are also using the retrospectroscope to a fair degree. 

That 1585hp figure for the Merlin is at 18lbs boost and yet the Standard Merlin 45/50 was good for 1470 to 1515hp at much higher altitudes using 16lbs boost.
better comparison is that at 3000rpm and 12lbs boost the cropped impeller engines were good for 1230hp for take-off and the uncropped engines were good for 1185hp.
Please note that again these were the ultimate ratings as finally decided in time. At some points in service the cropped impeller engines may have been allowed to use higher boost than the uncropped engines at certain altitudes. 
Like in Jan of 1942 the uncropped engines were limited to about 15lbs of boost by the end of 1942 this had changed 16lbs (not a big deal) but climb ratings were now being done at this power level and not restricted to 2850rpm an 9lbs of boost. 

The cropped impeller engines may have been rated at higher boost sooner (Jan 1942 saw the low geared Merlin 30 rated at 1lb more boost than any other Merlin) and again the fuel situation was in a state of flux. there was no 100/130 fuel in 1941 or the start of 1942. The cropped impeller engines _may have _been a way around the fuel limit until the supply of 100/130 fuel was a given. 
The Merlin 45 was limited to 9lbs (48in?) when first introduced and then changed to 12lbs (54in) and finally to 16lb ( 62in?) 

we have the luxury of knowing what fuels were to become available and when and what the engines were eventually modified to stand up to. 
For the US due to the distances from the factories to front lines it could often take 3-6 months for a production fighter to leave the factory and get into squadron service in a combat theater. That fighter would have had to have been ordered months if not a year before it rolled out the factory door inorder for all the subcontractor parts to be available. landing gear/tires. oil coolers, engine and propeller, instruments and a host of other parts (forgings/casting) that the factory did not make itself.


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## Schweik (Dec 11, 2018)

Stig1207 said:


> The USAAF stats certainly seem to portray a different picture than MAW does, for 1943 at any rate; with some 75% of USAAF fighter losses attributed to enemy aircraft according to the stats, just 11% to flak. As you yourself have remarked, in MAW fighter losses to flak are higher than that. Which numbers are off, I don't know, and I much prefer to think that there is a plausible explanation for why there is such a difference.
> 
> I agree on taking a single month or two and comparing the numbers, it's the way to go ; it will be interesting to see how it turns out.



Well to be clear, I was talking about MAW IV which is May 43 to Sept 44, and certainly the air to air casualties went down as the flak casualites went way up in 1944 which you can see in the Air Force journal records.

If there is a difference, and I'm not sure there is, it may boil down to how things like air to air collisions, engine failure etc. are counted.

But I agree the month analysis would be good to do, it may take a while though it's very busy lots of fighting with numerous claims and losses on both sides. A lot of transcribing.


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## Schweik (Dec 11, 2018)

tomo pauk said:


> By the time the 'cropped' superchargers were in use, the threat of Stukas was not present. Main threat/target were Fw 190s now (ie. early 1942 on).
> The Merlin 45 and 50 were 'normal' versions, with impeller diameter of 10.25 in. The 45M and 50M were the ones with cropped S/C (dia of 9.50 in - same as 'ordinary' V-1710s), so gains in low altitude were traded for loss of hi-alt power.



Stukas were still in heavy use all through the Med in 1942 and well into 1943 - quite devastating against some of the convoys too. But also used against Allied tanks including at El Alamein and Tobruk and so on right up to the end of the war in Tunisia. Also Ju 88 being used as torpedo bombers and (shallow angle) dive bombers, and various others including Dornier 217 (I think?) being used as carriers for Fritz guided missiles, He 111, SM 79 etc. etc. and Bf 109E and 110 Jabos. All needed to be shot down down low.

In Sicily and Italy the FW 190s were the main Jabos but they too were operating at low altitude. And the Ju 88's were still being sent out frequently (and getting wacked right and left).

My understanding of Merlin 45 and 50 (uncropped) is that they were still lower power rated engines just not as low as the cropped 45M and 50M.

S


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## Schweik (Dec 11, 2018)

varsity07840 said:


> There were no P-39s at Darwin.



My bad - I was thinking of Port Morseby, and apparently some other towns in Australia.

Aussie P-39 Airacobra – Emergency Defender

P-39 Airacobras in defence of Australia | The Australian War Memorial



> While oxygen was a problem with P-400s at Guadalcanal, P-39s did not have that problem. The record of P-400s and P-39s attempting to intercept bombers in New Guinea was poor at best. They were constantly bounced from above by escorting A6Ms. They did not have enough early warning time to get to altitude. AVG and 23rd FG P-40s benefited from adequate early warning as did Darwin P-40s, though perhaps to a lesser extant. P-40s in Java had no such luxury. The use of the P-39 and P-40 is a lesson in how US fighters were thrust into jobs that they were not intended for. They were not interceptors. The P-38 was an interceptor but forced into the high altitude escort role, among others where it did not excel.



All true. Part of what a fighter has to be is versatile. P-47s and Corsairs were never (originally) intended for ground attack and were in some respects unsuited, but the radial engines and heavy carrying capacity proved valuable in that role. Spits and 109s weren't really meant for bomber escort but they had to do it.


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## Schweik (Dec 11, 2018)

Shortround6 said:


> The P-40E was overweight, there is no" if, and or but" about it. The six .50 cal weapons installation was simply too heavy for the engine available. about 900lbs of guns and ammo which is several hundreds more than guns/ammo in a Spitfire V/IX or most of the the 1941-42 single engine fighters. It may be more than the FW 190. it may be triple what some of the Italian and Japanese fighters were carrying for armament.



It was actually not at all unusual for aircraft to start out just on the edge of enough engine power, but due to the dance between manufacturer and military, not yet equipped with all the 'stuff' needed for actual combat...and by the time that stuff was put in the plane became too heavy for the engine or the airframe. In the case of the P-40, my point was simply that the issue was the engine not the airframe.

The official engine settings (not just boost) for the earlier Tomahawk P-40 B/C and for the P-40D /E were too low. And there was a little too much weight in it. However this was changed in the field almost as soon as the aircraft went into combat. The British and Australians had figured out how to use the Tomahawk pretty quickly and had the luxury of sort of a slow ramp up in the Middle East as they were initially mostly facing not quite front line Italian fighters, Bf 110s and Vichy French fighters. When the P-40E arrived pilots really had to hit the ground running and did not have really any time to figure the plane out before they went up against elite enemy pilots flying world class fighters. This was true in North Africa where they were facing 109Fs of JG 27 etc., and in the Pacific where they were up against the best of the IJN and IJA flying A6M2s and Ki-43s.

However changes to the engine and experiments with stripping weight were going on from almost the first day of combat. They did take out guns, they took off with half fuel for intercept missions and so on during the debacle at Java and at Port Morseby / Milne Bay. The AVG also mentioned tinkering with their engines and doing all kinds of things (waxing, filling holes, sanding etc.) to speed up their Tomahawks and later Kittyhawks. Not sure about Darwin but I would be surprised if they didn't do it there as well as one of the commanders of the 49th FG had been at Java. The infamous Allison memo mentions their use "for considerable periods of time" .... "From Australia" at 70" / 20# per sq in boost and from the Middle East at 66" Hg (18# / sq. in.)." This was in Dec 42 but it's not clear how long it had already been going on. From other documents and interview excerpts I've read it had clearly become widespread practice to boost Kittyhawks to at least 60" by in the DAF mid 1942. That still leaves a few months where who knows what practices were going on at what squadrons but I have a feeling word got out pretty quickly.



> I would also note that the P-40D/E was initially rated with a combat load of 120 US gallons of gas. You could put an additional 28 US gallons in the rear fuselage tank but you basically had a 8100lb airplane with just that 120 US gallons of fuel and 1150hp engine



They were using external fuel tanks on P-40E from early on. Not sure about the D but a lot of the D models only had four guns.

S


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## tomo pauk (Dec 11, 2018)

Schweik said:


> Stukas were still in heavy use all through the Med in 1942 and well into 1943 - quite devastating against some of the convoys too. But also used against Allied tanks including at El Alamein and Tobruk and so on right up to the end of the war in Tunisia. Also Ju 88 being used as torpedo bombers and (shallow angle) dive bombers, and various others including Dornier 217  (I think?) being used as carriers for Fritz guided missiles, He 111, SM 79 etc. etc. and Bf 109E and 110 Jabos. All needed to be shot down down low.
> 
> In Sicily and Italy the FW 190s were the main Jabos but they too were operating at low altitude. And the Ju 88's were still being sent out frequently (and getting wacked right and left).



The 'ordinary' Spitfire V will have a field day against the listed Axis bombers, no need for low-alt engine. Please note that just a handful of Spitfires was deployed in Med before 1943.



> My understanding of Merlin 45 and 50 (uncropped) is that they were still lower power rated engines just not as low as the cropped 45M and 50M.
> 
> S



1500++ HP is hardly a sign of low power rated engine.


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## Schweik (Dec 11, 2018)

tomo pauk said:


> The 'ordinary' Spitfire V will have a field day against the listed Axis bombers, no need for low-alt engine. Please note that just a handful of Spitfires was deployed in Med before 1943.



You seem to be misunderstanding me here or missing my point. Yes the Spit V can have a field day against a Stuka or Ju 88, but they were defended by Bf 109, Mc 202, Mc 205, Re 2002 etc. They also had to catch Fw 190s. Apparently they felt they needed the low altitude versions.

*Large numbers of Spitfire Mk V were deployed to North Africa by mid 1942. Five squadrons: 92, 145, 601, 94, and 417 sqns were all flying Spitfires by El Alemein in Oct 42.*



> 1500++ HP is hardly a sign of low power rated engine.



*Low altitude *not low power. 1500 hp at 800 meters. Get it?


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## tomo pauk (Dec 11, 2018)

Schweik said:


> You seem to be misunderstanding me here or missing my point. Yes the Spit V can have a field day against a Stuka or Ju 88, but they were defended by Bf 109, Mc 202, Mc 205, Re 2002 etc. They also had to catch Fw 190s. Apparently they felt they needed the low altitude versions.



The Spitfire V with low-level engine (Merlin 45M, 50M or similar) cannot fight with the said fighters escorting the bombers as good as the Spit V with 'normal' engine (Merlin 45, 50) can.



> Large numbers of Spitfire Mk V were deployed to North Africa by mid 1942. Five squadrons: 92, 145, 601, 94, and 417 sqns were all flying Spitfires by El Alemein in Oct 42.



Before August of 1942 there was barely a Spitfire in N.A.



> Low _altitude_ not low power. 1500 hp at 800 meters. Get it?



Merlin 45 made more than 1500 HP at 11000 ft (3350m), and more than 1000 at 20000 ft. Get it?


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## Schweik (Dec 11, 2018)

> Please note that just a handful of Spitfires was deployed in Med before 1943.
> Before August of 1942 there was barely a Spitfire in N.A.



Ok Tomo, you seem to be moving the bar a bit here, and I'm not sure precisely what you are getting at? You tell me why they (obviously quite on purpose) created low altitude fighters with low-altitude rated engines? 

Or are you claiming that they didn't?


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## tomo pauk (Dec 11, 2018)

Schweik said:


> Ok Tomo, you seem to be moving the bar a bit here, and I'm not sure precisely what you are getting at? You tell me why they (obviously quite on purpose) created low altitude fighters with low-altitude rated engines?
> 
> Or are you claiming that they didn't?



They certainly did, the low-altitude versions of Merlins are listed at the tables I've posted at post #170 here.
Low-altitude Merlins were created in order to improve performance down low. These come in handy once the threat emerged - Fw 190s armed with bombs, trying to make hit & run attacks against the targets in UK proper. Typhoon was barely available and beset with problems, Griffon was running late.
Low-alt Merlins were also used on 'hooked Spitfires' and Seafires, where improved low-alt power obviously improved take-off properties and enabled carrying more, as well (but not exclusively) on bomb-armed Spitfires.

Low-alt Spitfires usualy sported clipped wings, in effort to improve rate of roll. The Spitfires VIII and XI were produced in LF, F and HF versions, actual difference being the sub-type of 2-stage Merlin aboard. Usually the LF (L for low altitude) was with clipped wings, HF (H for hi-alt) was with extended wingtips; F was with standard wings.


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## Schweik (Dec 11, 2018)

Well the Fw 190 Jabos were in full effect in Sicily and Italy by 1943 (and in fact were already being used in Tunisia in 42) so lets try not to forget that perpetually overlooked part of the war... though Ju 87 and Ju 88 and the other aircraft I mentioned were important there as well (much longer than in North West Europe).

As to how easy they were to kill, I am not certain about that, the survival rate of Ju 87s was perhaps surprisingly pretty good in North Africa, most of the casualties on both sides were fighters. Ju 88's were also pretty elusive though that seems to have been due more to _high_ altitude performance generally (Hurricanes in particular had a hard time catching them over the Med). But I think extra speed and agility near sea level was particularly helpful for catching torpedo planes down low. 'Fritz' carrying bombers also seemed to be a significant threat that needed to be quickly neutralized especially during amphibious operations such as were repeatedly taking place in the Med in 1943.

I'm not convinced that the only reason LF spits and low altitude / cropped merlins were made was due to Fw 190s fighting over England or the Channel, but it's immaterial to the discussion really. My original point was simply that aircraft which performed well down low _did_ have a role and _were _valuable. The "Bomber Mafia" and other generals may have only liked the high flying 4 engine bomber escorts but a lot of the fighting worldwide was done on the deck.

To reiterate my previous point destroying or protecting dive bombers, torpedo bombers, heavily laden (and thus relatively defenseless) fighter bombers and strafer / attack aircraft was the main mission of fighters in many if not most Theaters of WW2. Some units may have preferred to focus on racking up kill ratios against whatever the easiest targets were at any given moment, but this probably contributed to their defeat.

Four engine heavy bombers were only flying in the daylight under American auspices as far as I know, and the really long range (and thus, more damaging) raids didn't get going until near 1944. And while they no doubt affected the war, especially through attrition of the Luftwaffe and the Japanese air forces, I don't think you can say that they decided the outcome of the war. The crucial battles were fought earlier and they were Tactical battles, involving land armies or navies. And in those fights the lower flying fighters actually mattered more, most significantly on the Russian Front but also in the Med and Pacific.

S


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## tomo pauk (Dec 11, 2018)

Schweik said:


> Well the Fw 190 Jabos were in full effect in Sicily and Italy by 1943 (and in fact were already being used in Tunisia in 42) so lets try not to forget that perpetually overlooked part of the war... though Ju 87 and Ju 88 and the other aircraft I mentioned were important there as well (much longer than in North West Europe).



The Jabo Fw 190s were operating very much in 1942 over the Channel.



> As to how easy they were to kill, I am not certain about that, the survival rate of Ju 87s was perhaps surprisingly pretty good in North Africa, most of the casualties on both sides were fighters. Ju 88's were also pretty elusive though that seems to have been due more to _high_ altitude performance generally (Hurricanes in particular had a hard time catching them over the Med). But I think extra speed and agility near sea level was particularly helpful for catching torpedo planes down low. 'Fritz' carrying bombers also seemed to be a significant threat that needed to be quickly neutralized especially during amphibious operations such as were repeatedly taking place in the Med in 1943.



For the n-th time - 'ordinary' Spitfires have had plenty of performance to catch any bomber fielded by Axis, whether a Ju 88 at 15000 ft or SM.79 at 500 ft. But for catching Jabo Fw 190s, Spitfires needed any help they can get, and low-alt Merlins gave them some 150 HP extra down low.
The Do 217s with Fritz X bombs were flying at medium altitudes.



> I'm not convinced that the only reason LF spits and low altitude / cropped merlins were made was due to Fw 190s fighting over England or the Channel, but it's immaterial to the discussion really. My original point was simply that aircraft which performed well down low _did_ have a role and _were _valuable. The "Bomber Mafia" and other generals may have only liked the high flying 4 engine bomber escorts but a lot of the fighting worldwide was done on the deck.



Have you actually read the post above, where the other users of low-alt Merlins are listed?
Low-level fighters did have a role, quirk being that hi-alt fighters were priority in at ETO and MTO, plus in Asia/PAcific. Once that priority is satisfied, the lo-alt fighters were made and pressed in service (or not, in Japanese case). Bomber mafia got many things wrong, however high flying escorts were needed to bring the 'daylight war' to German proper. 
It was far easier to turn a hi-alt fighter into low-alt, than vice-versa.



> To reiterate my previous point destroying or protecting dive bombers, torpedo bombers, heavily laden (and thus relatively defenseless) fighter bombers and strafer / attack aircraft was the main mission of fighters in many if not most Theaters of WW2. Some units may have preferred to focus on racking up kill ratios against whatever the easiest targets were at any given moment, but this probably contributed to their defeat.
> 
> Four engine heavy bombers were only flying in the daylight under American auspices as far as I know, and the really long range (and thus, more damaging) raids didn't get going until near 1944. And while they no doubt affected the war, especially through attrition of the Luftwaffe and the Japanese air forces, I don't think you can say that they decided the outcome of the war. The crucial battles were fought earlier and they were Tactical battles, involving land armies or navies. And in those fights the lower flying fighters actually mattered more, most significantly on the Russian Front but also in the Med and Pacific.
> S



Outcome of war was not decided by P-40s either, that was decided by many sacrifices at Allied side and German mistakes - boy, did they made them. P-40 was not there to decide BoB, and it's influence in survival of Soviet Union in 1941-42 was minimal. 4-engined bombers flew against Germany most of 1943, wheather & losses .permitting. That they didn't achieved more was due to lack of suitable escort.
In Pacific both Allied and Japan were very much interested in hi-alt aerial warfare, and acted accordingly. USN predominatly used fighters with 2-stage engines, AAF wanted turboed engines ASAP, while Japanese engines have had better hi-alt capabilites than V-1710s as installed on P-40s.


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## varsity07840 (Dec 11, 2018)

Schweik said:


> My bad - I was thinking of Port Morseby, and apparently some other towns in Australia.
> 
> Aussie P-39 Airacobra – Emergency Defender
> 
> ...


It's interesting to note that the "Emergency Defender" article mentions that the P-39 had poor altitude performance due to the lack of "an effective turbo-supercharger". The inference being that fighters with good altitude performance had turbo chargers when in fact most did not. There's a similar misunderstanding about stage speed vs. two stage engines. In some cases writers have claimed that the P-39 and P-40 did not have supercharging.

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## wuzak (Dec 11, 2018)

Schweik said:


> Yes but lets be real the LF Spit Mk V, many regular Spit V, recon Spit IV and various others were using other specifically low altitude optimized Merlin engines like the Merlin 45, 45M, 50, 50M etc. some of which had cropped impellers specifically for low altitude power. For example Merlin 45M had a critical altitude of 2,750 ft (838 m) where it gave 1585 hp. Interestingly this is about the equivalent of the P-40K (which the English liked quite a bit) at normal / sanctioned WEP settings.



For your information, the Spitfire PR.IV (nee ID) was an unarmed high altitude long range reconnaissance aircraft. Fitting a low critical altitude engine would have been dumb. So they fitted the 45.


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## Schweik (Dec 11, 2018)

> Outcome of war was not decided by P-40s either, that was decided by many sacrifices at Allied side and German mistakes - boy, did they made them. P-40 was not there to decide BoB, and it's influence in survival of Soviet Union in 1941-42 was minimal. 4-engined bombers flew against Germany most of 1943, wheather & losses .permitting. That they didn't achieved more was due to lack of suitable escort.
> In Pacific both Allied and Japan were very much interested in hi-alt aerial warfare, and acted accordingly. USN predominatly used fighters with 2-stage engines, AAF wanted turboed engines ASAP, while Japanese engines have had better hi-alt capabilites than V-1710s as installed on P-40s.



I never made such grandiose claims for the P-40. No single aircraft or any other piece of equipment decided the outcome of the war, not the P-51, not the Spitfire or the Sherman tank or the Aircraft Carrier. Not even the A-bomb.

But I will help you out - I will say that think the P-40 did play a_ significant_ and generally little known role in the crucial mid-war battles in all three Theaters you just mentioned


Russia - particularly in the key battles at Moscow and Leningrad
In the Med - where it was the main air superiority fighter until August 1942 at the earliest and maybe the most important Allied Tactical bomber as well)
and the Pacific -where according to the local ground commander it played the "decisive role" in the critical battle of Milne Bay* and contributed significantly to the defense of Darwin and the fighting around New Guinea and in the Solomons.


And finally in the CBI it clearly was the most important Allied fighter and significantly helped keep the Chinese in the war.

A bunch of other Allied fighters were equally important during 1942 - the Hurricane, Yak 1, LaGG-3, Wildcat, P-39, early P-38 and Spit V, but I think the P-40 was clearly a major part of many of the decisive battles during the turning point of the war - where victory or defeat in fact hinged on low altitude combat. Even at times where the fighting took place at higher altitudes in these Theaters, such as over Darwin, the aircraft proved versatile enough to remain effective.

And Northwest Europe wasn't the only important Theater in WW2.

S

* "After the war, the Australian Army commemorated the battle through the awarding of a battle honour titled "Milne Bay" to a number of the units that took part. The units chosen were the 9th, 25th, 61st, 2/9th, 2/10th and 2/12th Infantry Battalions.[170] The two RAAF fighter squadrons that had taken part in the fighting were also singled out for praise by the Australian commanders for their role in the battle. Rowell stated: "the action of 75 and 76 Squadrons RAAF on the first day was probably the decisive factor", a view Clowes endorsed in his own report.[171] "

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## Schweik (Dec 11, 2018)

varsity07840 said:


> It's interesting to note that the "Emergency Defender" article mentions that the P-39 had poor altitude performance due to the lack of "an effective turbo-supercharger". The inference being that fighters with good altitude performance had turbo chargers when in fact most did not. There's a similar misunderstanding about stage speed vs. two stage engines. In some cases writers have claimed that the P-39 and P-40 did not have supercharging.



Again, I'm not an expert on Spitfires or Merlins, but I was going by the description of the Merlin 45 here as _"A variant of the Merlin XX fitted with * single-stage, single-speed supercharger for low altitude Spitfire use*. First production Merlin 45 delivered 13 January 1941.[6] First of specialised engines for Spitfire Mk V variants and early Seafires._ "

Spitfire PR Mk. IV was listed as one of the aircraft fitted with the engine. I think they did also require low altitude recon aircraft due to the limitations of cameras back then, certainly the Spit Mk IV's operating in the Med seemed to get shot down at low altitude more than once.

Are you saying that description is wrong?


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## wuzak (Dec 11, 2018)

Schweik said:


> Ok Tomo, you seem to be moving the bar a bit here, and I'm not sure precisely what you are getting at? You tell me why they (obviously quite on purpose) created low altitude fighters with low-altitude rated engines?
> 
> Or are you claiming that they didn't?



They did, for the express purpose of fighting Fw 190 intruders over England. They were aircraft modified for the purpose, using modified engines.

The IX had started operational service in mid 1942, but its engine (Merlin 63) was high altitude rated. The LF.IX doesn't appear until 1944. The LF.IX used the Merlin 66, which was stronger, so could take more boost, and had different gearing so it had a lower critical altitude. At +18psi boost the 66 had a critical altitude of 5,250ft in low gear and 12,500ft in high gear.

Note that the Merlin 66 was built under licence by Packard as the 266 for British service and as the V-1650-7 for American service. The V-1650-7 saw use in the P-51B and P-51D, neither of which would be considered low altitude fighters.

The reason to go from the V-1650-3 (Merlin 63) to the lower critical altitude -7 was the increase in mid-altitude performance.


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## Schweik (Dec 11, 2018)

wuzak said:


> They did, for the express purpose of fighting Fw 190 intruders over England. They were aircraft modified for the purpose, using modified engines.



I am really not sure what you or Tomo are driving at aside from "I'm right / you're wrong".

What I originally said that started this avalanche of posts, was that there was an actual _purpose_ for low altitude fighters, and that they were made_ intentionally._ I mentioned LF Spitfires as one example, the LF Mk V was in fact made with a variety of early low altitude rated Merlin engines of which I already mentioned several examples - Merlin 45 and 45M, 50 and 50M, and Tomo also pointed out the Merlin 32.

The Tempest and Typhoon were also low altitude fighters.

And almost all of the Soviet fighters were low altitude fighters -and no this was not done after they had already secured a sufficient number of high-altitude fighters. The one high altitude fighter they had, the MiG 3, they basically thought was useless because it performed badly down low, and they thought the P-47 was "not a fighter" to quote the evaluation verbatim.

The early Zeros by the way, did not have very high altitude performance ceilings either, nor did Hurricanes at least not in the Med (they were often unable to intercept high flying aircraft over Malta for example) nor quite a few other early and mid war fighters.


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## tomo pauk (Dec 11, 2018)

Schweik said:


> Again, I'm not an expert on Spitfires or Merlins, but I was going by the description of the Merlin 45 here as _"A variant of the Merlin XX fitted with * single-stage, single-speed supercharger for low altitude Spitfire use*. First production Merlin 45 delivered 13 January 1941.[6] First of specialised engines for Spitfire Mk V variants and early Seafires._ "
> 
> Spitfire PR Mk. IV was listed as one of the aircraft fitted with the engine. I think they did also require low altitude recon aircraft due to the limitations of cameras back then, certainly the Spit Mk IV's operating in the Med seemed to get shot down at low altitude more than once.
> 
> Are you saying that description is wrong?



The description *is* wrong.

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## Schweik (Dec 11, 2018)

tomo pauk said:


> The description *is* wrong.



Ok so did they or did they not put Merlin 45M into Spitfire LF Mk V fighters?


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## wuzak (Dec 11, 2018)

Schweik said:


> Again, I'm not an expert on Spitfires or Merlins, but I was going by the description of the Merlin 45 here as _"A variant of the Merlin XX fitted with * single-stage, single-speed supercharger for low altitude Spitfire use*. First production Merlin 45 delivered 13 January 1941.[6] First of specialised engines for Spitfire Mk V variants and early Seafires._ "



Yes.

The supercharger was the same as the XX.

The XX had gear ratios of 8.15:1 (low gear) and 9.49:1 in high gear.

The 45 supercharger gear ratio was 9.09:1.

So while the 45 had a lower critical altitude than the XX in high gear, it still had a relatively high critical altitude for 1941.




Schweik said:


> Spitfire PR Mk. IV was listed as one of the aircraft fitted with the engine. I think they did also require low altitude recon aircraft due to the limitations of cameras back then, certainly the Spit Mk IV's operating in the Med seemed to get shot down at low altitude more than once.



The PR.IV carried the same cameras as the PR.IX and PR.XIX, so I doubt cameras were a problem.

Photo Reconnaissance Spitfires

Would need citation on the PR.IVs being shot down at low altitude.


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## wuzak (Dec 11, 2018)

Schweik said:


> Ok so did they or did they not put Merlin 45M into Spitfire LF Mk V fighters?



The 45M is a modified 45, hence the M.

Your description was for the regular 45.


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## varsity07840 (Dec 11, 2018)

Schweik said:


> My bad - I was thinking of Port Morseby, and apparently some other towns in Australia.
> 
> Aussie P-39 Airacobra – Emergency Defender
> 
> ...


It's interesting to note that the "Emergency Defender" article mentions that the P-39 had poor altitude performance due to the lack of "an effective turbo-charger". The inference being that fighters with good altitude performance were turbo-charged when in fact that's not the case. There is a similar confusion between two speed and two stage engines. Some writers have claimed that the P-39 and P-40 did not have superchargers.


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## tomo pauk (Dec 11, 2018)

Schweik said:


> Ok so did they or did they not put Merlin 45M into Spitfire LF Mk V fighters?



They did.
I'm not sure how many times it needs to be said: Merlin 45 and 50 were 'normal' Merlins, all-altitude if you want. Merlin 45M and 50M were low-alt versions, used where low-alt performance was a paramount, offering up to 10% more power down lwo, while having less power at mediu and high altitudes than 'normal' versions.


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## P-39 Expert (Dec 11, 2018)

Schweik said:


> But that isn't actually true. You didn't understand what you have been reading. Performance, especially climb, fell off starting at 12,000 ' and climb rate was no doubt very bad by 20,000', but that was not the ceiling. They routinely intercepted enemy bombers flying much higher than that. You should read this article which I posted previously, about the use of P-40s in the defense of Darwin. From March to September 1942, Japanese records confirm that novice P-40E pilots from the 49th FG were able to shoot down 12 "Betty" bombers flying at 27,000' in spite of a heavy escort of A6M2s so not only were they able to fly that high, they were fairly effective in combat (albeit with heavy losses of their own) .
> 
> Quote from the article:
> 
> ...


I have read those articles and there is no way possible on this earth that a P-40E ever intercepted ANYTHING at 27000'. It's absolute ceiling was 31000' and it's rate of climb at 27000' was 250fpm. It took a staggering 30+ minutes to climb to 27000' under test conditions (not combat). At 27000' it's top speed was 250mph. It couldn't intercept anything at that altitude. 

The Bettys that they intercepted couldn't even get that high. The altitude figures in that article had to be a mistake or an exaggeration. Just my opinion.


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## Schweik (Dec 11, 2018)

wuzak said:


> Yes. The supercharger was the same as the XX.
> 
> So while the 45 had a lower critical altitude than the XX in high gear, it still had a relatively high critical altitude for 1941.



Well I guess it depends on your definition of low altitude. The P-40F (also made in 1941) and L had a Merlin 28, essentially Merlin XX, and a critical altitude of about 20,000 ft. Which is considered low - certainly not high enough for escorting B-17s. According to this page Merlin 45 had 1,515 hp at 11,000 ft and 1,210 hp with +3 boost at 18,000 ft which sounds kind of similar. Is it wrong?



> Would need citation on the PR.IVs being shot down at low altitude.



A while back I think I posted a bunch of data from Shores MAW Volume III in one of the air battles a Spit IV PR blundered into a dogfight between P-40s and Bf 109s and got shot down by the latter, I think it's in the p-40 vs. 109 thread which I believe you also posted to. 



> The 45M is a modified 45, hence the M. Your description was for the regular 45.



This is from the wiki:

List of Rolls-Royce Merlin variants - Wikipedia

_Merlin 45M 1,230 hp (917 kW) at 3,000 rpm 1,585 hp (1,182 kW) at 3,000 rpm, +18 psi (124 kPa) boost, 2,750 ft (838 m) Spitfire LF Mk.V Version of Merlin 45 with "cropped" (smaller diameter) supercharger impeller allowing greater boost at low altitudes._


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## Schweik (Dec 11, 2018)

tomo pauk said:


> They did.
> I'm not sure how many times it needs to be said: Merlin 45 and 50 were 'normal' Merlins, all-altitude if you want. Merlin 45M and 50M were low-alt versions, used where low-alt performance was a paramount, offering up to 10% more power down lwo, while having less power at mediu and high altitudes than 'normal' versions.



So I don't know how many times I have to say this - there was a purpose and a need for low altitude fighters. And the Spit V LF was one example. It matters very little to me if that used a Merlin 45 or a 45M or a 50M or whatever. Point is it wasn't just for Seafires.

By the way Wiki also mentions that the "low altitude" merlin 32 was also used on the Spitfire PR Mk. XIII (with citation from _The Spitfire Story_. London: Jane's Publishing Company Ltd., 1982. ISBN 0-86720-624-1. pages 182 and 185)


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## Schweik (Dec 11, 2018)

P-39 Expert said:


> I have read those articles and there is no way possible on this earth that a P-40E ever intercepted ANYTHING at 27000'. It's absolute ceiling was 31000' and it's rate of climb at 27000' was 250fpm. It took a staggering 30+ minutes to climb to 27000' under test conditions (not combat). At 27000' it's top speed was 250mph. It couldn't intercept anything at that altitude.
> 
> The Bettys that they intercepted couldn't even get that high. The altitude figures in that article had to be a mistake or an exaggeration. Just my opinion.



I get that you don't understand it, but you probably just have to read a bit more on the subject to understand how it all worked. History doesn't have to make sense to you, you have to figure it out.


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## Schweik (Dec 11, 2018)

varsity07840 said:


> It's interesting to note that the "Emergency Defender" article mentions that the P-39 had poor altitude performance due to the lack of "an effective turbo-charger". The inference being that fighters with good altitude performance were turbo-charged when in fact that's not the case. There is a similar confusion between two speed and two stage engines. Some writers have claimed that the P-39 and P-40 did not have superchargers.



yes I agree it's a common misconception and one of the things I often try to debunk.


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## tomo pauk (Dec 11, 2018)

Schweik said:


> The Tempest and Typhoon were also low altitude fighters.
> 
> And almost all of the Soviet fighters were low altitude fighters -and no this was not done after they had already secured a sufficient number of high-altitude fighters. The one high altitude fighter they had, the MiG 3, they basically thought was useless because it performed badly down low, and they thought the P-47 was "not a fighter" to quote the evaluation verbatim.
> 
> The early Zeros by the way, did not have very high altitude performance ceilings either, nor did Hurricanes at least not in the Med (they were often unable to intercept high flying aircraft over Malta for example) nor quite a few other early and mid war fighters.



Both Tempest and Typhoon were far better than P-40 at any altitude.Tempest was better than Fw 190A of any type at any altitude, and about as good as Fw 190D-9. Sabre was making almost twice the power of 1-stage V-1710 above 15000 ft, and 500-700 HP more under 10000 ft.
Soviet fighters being good just at low altitude was a bug, not a feature. Ditto for their performance and range. MiG-3 was too ligthly armed by Soviet standards, used the engine produced at factories that were also supplying the Il-2 needs, the cockpit was so bad that pilots preferred to fly with open cockpit (hence killing lots of speed).
In 1942, Zeroes were far better hi-alt fighters than P-40s, and Japan produced other fighters that were not Zeroes. Hurricane was a draggy affair, engine was able to help just that much.



Schweik said:


> So I don't know how many times I have to say this - there was a purpose and a need for low altitude fighters. And the Spit V LF was one example.



There was a purpose.
Please note that 1st and foremost people were trying to introduce 'all-altitude' fighters, and, once that was sattisfied, they introduced specific fighters for high altitudes and low altitudes. Unfortunately, there was no 'HF' P-40s or P-39s, due to V-1710 being about as good as Merlin 45M, altitude-wise.

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## tomo pauk (Dec 11, 2018)

Schweik said:


> So I don't know how many times I have to say this - there was a purpose and a need for low altitude fighters. And the Spit V LF was one example. It matters very little to me if that used a Merlin 45 or a 45M or a 50M or whatever. Point is it wasn't just for Seafires.
> 
> By the way Wiki also mentions that the "low altitude" merlin 32 was also used on the Spitfire PR Mk. XIII (with citation from _The Spitfire Story_. London: Jane's Publishing Company Ltd., 1982. ISBN 0-86720-624-1. pages 182 and 185)



Spit VLF will use Merlin 45M or 50M, but not 45. Just for Seafires??
The PR XIII was a spin-off from FR versions, low-level recon, lightly armed (4 .303s), not a long-rage hi-alt recon like vast majority of PR Spits were. FR meaning 'fighter-recon'.


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## Shortround6 (Dec 11, 2018)

Schweik said:


> It was actually not at all unusual for aircraft to start out just on the edge of enough engine power, but due to the dance between manufacturer and military, not yet equipped with all the 'stuff' needed for actual combat...and by the time that stuff was put in the plane became too heavy for the engine or the airframe. In the case of the P-40, my point was simply that the issue was the engine not the airframe.


In reverse. 

"_They were using external fuel tanks on P-40E from early on. Not sure about the D but a lot of the D models only had four guns_."

ALL of the Ds had 4 guns, but according to some sources there were only about 30 Ds (or 30 built for the US) built before the contracts were amended to E models so the point is rather moot.
Some (all?) of the US Ds saw use in Hawaii. 
With full internal tanks the D/E was good for 148 gallons, with drop tank the total capacity was 200 gallons. Point is that even with drop tank gone you can't fill the internal tanks and keep the plane under 8100lbs unless you take out guns/ammo. Filling the internal tank/s means an additional 168lbs. 

"_However changes to the engine and experiments with stripping weight were going on from almost the first day of combat. They did take out guns, they took off with half fuel for intercept missions and so on during the debacle at Java and at Port Morseby / Milne Bay. The AVG also mentioned tinkering with their engines and doing all kinds of things (waxing, filling holes, sanding etc.) to speed up their Tomahawks and later Kittyhawks. Not sure about Darwin but I would be surprised if they didn't do it there as well as one of the commanders of the 49th FG had been at Java._"

I love the bit about _tinkering_ the engines. Nobody ever says what was done. You can't do much with the timing. Allison ignition timing was fixed, there was no variable advance. You can either set it up for a little more advance or retard it a little but then either your starting and idle/slow speed cruise are affected. or the top end is affected. There were a variety of approved spark plugs and perhaps one or two degrees timing change worked better with plug han another? 
You can't change the valve timing. You can change the valve clearance but why? 
You can change the jets in the carburetor (assuming you have different jets or spares to drill out) but there again you have very narrow window of possibilities and what works at one temperature/air pressure situation is worse than standard at a different temperature/air pressure situation. 
The big thing that could be done and was done once WEP power settings were approved was to hacksaw off the ends of the exhaust stacks to open them up and reduce back pressure at the higher power settings. please note that this may have lowered the exhaust gas velocity at standard power settings (climb and cruise) for loss of power/thrust under those conditions. 
Working on supercharged aircraft engines is a lot different than working on a 1940s Chevy six or Ford Flat head V-8. 

Taking weight out helped but please look at the factory strippers. The Early P-40L and the Early P-40N. the chances of any squadron mechanics getting a P-40 pf any type down to the weight of an an early P-40N are about zero unless they had access to aluminium radiators and oil coolers, maganismum wheels, lighter tires, used four guns and restricted the four guns to 200 rounds per gun, pulled out the electric starter for the engine (leaving hand crank only) and took out the battery or substituted much smaller one ( a mark of desperation for a plane that used an electric propeller. If the generator fails how long before the prop becomes a fixed pitch prop at best or runs away at worst. 

1/2 fuel mans what? 100 US gallons if you count the drop tank? 74 US gallons if you don't ? 60 US gallons (50 imp gallons) if it is 1/2 the "book" combat fuel load? 
A P-40E was going to use over 40 US gallons just starting, taking off and climbing to 20,000ft. Figure another 8-13 gallons to make it to 25,000ft. 
In combat the engine might use 1 to 1/2 gallons a minute at high altitude. (much more at lower altitudes).

Sorry, gliding back to the airfield after an intercept doesn't sound like that great of an idea. Reduced fuel yes but 1/2??? 

"_The official engine settings (not just boost) for the earlier Tomahawk P-40 B/C and for the P-40D /E were too low. And there was a little too much weight in it. However this was changed in the field almost as soon as the aircraft went into combat_. "

Now this needs a bit of looking at too as there were several changes to the engines used in the Tomahawk P-40 B/C that do NOT show up as changes in the engine type. 
Allison had to call back 277 (?) of the original -33 engines and rework them at company expense because they were failing well before the expected overhaul life. Changes included but were not limited to a new crankshaft and new crankcase. Until the rework was done the planes continued to fly with the engine restricted to 2770 rpm and with restricted boost pressure. I don't know if the British got any of these engines or if all went into early US production. In any case it may well have made both Allison and the US army at bit hesitant to approve high boost levels on that "2nd" generation -33 engine until the service life was proved out (and it did have considerably more life than the originals, not just meeting the original goal).
You also run smack into the the fuel situation. British (and commonwealth) fuel in 1940 and 1941 was the equivalent to 100/115-120 so a fair amount of over boosting could be done as shown by the Merlins in the BoB going from 6lbs (42in) 12lbs (54in) however US fuel at this time was 100/100. Over boost this stuff at your own risk. The US did specify/but and issue (for testing?) some 100/125 and many US engines of this time period (1940-41) were rated to use this grade but information on use in service is limited (nearly no existent one way or the other). The British and the US coming up with the first of many specifications for 100/130 fuel (1st specification limited the lead use to 3cc per imp gallon). The 100/130 fuel showing up about the time many of the planes were (although the amount of 100/130 fuel in the Philippines might be subject to question).
Back to the engines, the first Allisons used a "plain" steel crankshaft. I don't know when it was changed, Plain steel means a high grade steel alloy suitable heat treated. At some point they went to shot peening the crankshaft. I don't know if this was part of the _fix_ for the early engines or if it came latter. These crankshafts had much improved fatigue life. By the end of 1941 ( and after over 1000 P-40Es had been built) the crankshaft was changed to one that was both nitrided and shot peened for another very significant increase in both strength and fatigue life. It was this crankshaft that allowed the 1325hp take of rating in the P-40K (after hundreds if not thousands of hours of testing, both factory and operational).
Saying that early P-40Es could have been over boosted like the P-40Ks were given the different crankshaft and possibly different fuels is pushing things.
They were were overboosted but squadron records don't seem to show the failure rate. And the failure rate has to take into account the availability rate (number of planes grounded with metal bits in the oil waiting for an engine change) and not just the number of crashes due to engine failure. How many minutes/hours at how much over boost before engine failure?
compounded by the crappy operating conditions. does the crankshaft fail from fatigue before or after the engine bearings are wrecked by sand/grit in the oil? 

" _It was actually not at all unusual for aircraft to start out just on the edge of enough engine power, but due to the dance between manufacturer and military, not yet equipped with all the 'stuff' needed for actual combat...and by the time that stuff was put in the plane became too heavy for the engine or the airframe. In the case of the P-40, my point was simply that the issue was the engine not the airframe_." 

There was no "dance" between the manufactures and the military. In 1939-40 there was a change in what was required in military aircraft in many countries. Curtiss lost over $14,000 when the 2nd XP-46 with full military equipment failed to come close to the projected performance figures. Please note that the P-40D/E was a back up to the XP-46 using the same engine as a low risk----low loss of production alternative. 
Armor, self sealing tanks, good radios and more than a handful of rifle caliber machine guns were all just starting to be fitted to most fighter aircraft in 1939/early 1940.
Early Bf 109Es having just four 7.9mm machine guns, little or no armor and no self sealing tanks during the attack on Poland. Trying to say that aircraft companies/designers were using smaller than needed engines and getting by by skimping on military equipment is not an accurate picture. There simply weren't any more powerful engines in a suitable stage of development using the fuel available to each country at the time. In 1939/40 the US didn't have any liquid cooled engine anywhere near production status except the Allison and there was no good air cooled radial alternative. For instance the 1700hp version of the Wright R-2600 didn't start design work until the same month the P-40D/E was ordered. The first prototype engine ran a few months later (about the start of the BoB) but the 5th production engine was not built until over a year later. Oct of 1941 

The issue was not the engine, it was the airframe/service load. 
Please compare the Allison to the Merlin 45. You could drop a Merlin 45 into a P-40 with not a lot of change in performance until you get to around 18,000ft. You could drop an Allison into a Spitfire MK V and if you allow over boosting probably get similar performance up until about 18,000ft. 
The Allison is about 3.6% bigger in displacement and uses about 10% more compression so at the same rpm and boost pressure it should make a bit more power. 

from this test : Spitfire F. Mk.VB Climb and level speed performance

we can see that a Spitfire V with a cropped impeller Merlin 50 engine could hold 6lbs boost (42in ) to 16,000ft with the RAM supplied by climb speed. At max level speed it could hold 6.2 pounds to 18,000ft. it can only hold 18lbs/66in (18.2 in the test airplane) to 3800ft when climbing so it isn't that different from an Allison with 8.80 supercharger gears.

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## tomo pauk (Dec 11, 2018)

Shortround6 said:


> ...
> 
> The issue was not the engine, it was the airframe/service load.
> Please compare the Allison to the Merlin 45. You could drop a Merlin 45 into a P-40 with not a lot of change in performance until you get to around 18,000ft. You could drop an Allison into a Spitfire MK V and if you allow over boosting probably get similar performance up until about 18,000ft.
> ...



Welcome back 
Now to the point - with P-40, it was very much about engine, too. In 1941-late 1942, Merlin 45 vs. V-1710-33 or -39 means at least 25% extra power for no gain in weight. For example, at 15000 ft, it is 1030 HP vs. 1300+. No ram.
Come late 1942, Spitfire gets Merlin 61, P-40 gets an improved V-1710 - no contest at all, Spitfire's engine has more power at 25000 ft than P-40s at 15000 ft.


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## wuzak (Dec 11, 2018)

Schweik said:


> Well I guess it depends on your definition of low altitude. The P-40F (also made in 1941) and L had a Merlin 28, essentially Merlin XX, and a critical altitude of about 20,000 ft. Which is considered low - certainly not high enough for escorting B-17s. According to this page Merlin 45 had 1,515 hp at 11,000 ft and 1,210 hp with +3 boost at 18,000 ft which sounds kind of similar. Is it wrong?



20,000ft is what would have been considered mid-altitudes.

The advantage a higher critical altitude engine is maintained at altitudes above that critical altitude, if not widening the gap.

+3psi boost would be a cruising setting.

http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Rolls-Royce_Merlin.pdf

This shows the 45 as having:
1,185hp @ 3,000rpm for take-off, +12psi boost
1,515hp @ 3,000rpm @ 11,000ft, presumably at +12psi boost
1,200hp @ 2,850rpm @ 16,000ft - probably a +9psi boost (rated power)
1,060hp @ 2,650rpm @ 14,500ft - cruising.

The Spitfire inability to escort the B-17s was not because of altitude performance, but because of range.

At 30,000ft the Spitfire V with Merlin 45 could still do ~340mph TAS.
http://www.wwiiaircraftperformance.org/Spitfire_V_Level_Speed_RAE.jpg

Also, the Spitfire Mk.III with Merlin XX would have been a genuine 400mph aircraft, but production requirements saw the V go into production instead, it basically being a Mk II with a Merlin 45 and not requiring extensive changes.



Schweik said:


> A while back I think I posted a bunch of data from Shores MAW Volume III in one of the air battles a Spit IV PR blundered into a dogfight between P-40s and Bf 109s and got shot down by the latter, I think it's in the p-40 vs. 109 thread which I believe you also posted to.



So, one PR.IV gets shot down at a lower altitude = PR.IV was a low altitude aircraft?

Question: Where did this occur? Near home base for the Allies?




Schweik said:


> List of Rolls-Royce Merlin variants - Wikipedia
> 
> _Merlin 45M 1,230 hp (917 kW) at 3,000 rpm 1,585 hp (1,182 kW) at 3,000 rpm, +18 psi (124 kPa) boost, 2,750 ft (838 m) Spitfire LF Mk.V Version of Merlin 45 with "cropped" (smaller diameter) supercharger impeller allowing greater boost at low altitudes._



Yes, the 45M and 50M were the low altitude versions of the 45 and 50, respectively.


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## Shortround6 (Dec 11, 2018)

Schweik said:


> Well I guess it depends on your definition of low altitude. The P-40F (also made in 1941) and L had a Merlin 28, essentially Merlin XX, and a critical altitude of about 20,000 ft. Which is considered low - certainly not high enough for escorting B-17s. According to this page Merlin 45 had 1,515 hp at 11,000 ft and 1,210 hp with +3 boost at 18,000 ft which sounds kind of similar. Is it wrong?



a lot depends on timing and actual missions to be performed. A "critical altitude" of 20,000ft was actually not bad in the early part of 1942 when the P-40F went into production (basic engine was well over a year old having gone into Hurricane IIs in the fall of 1940. It had a critical altitude about 7,000ft higher than an Allison in a P-40E and not that different than the two stage supercharged P & W R-1830 Used in the F4F. Please note that the two stage R-2800 used in the Corsair and Hellcat is months away from quantity production ( more than 20 or so a month) .

The power quotes you give are using the retrospectroscope. When introduced in the spring of 1941 the Melrin 45 was limited to 9lbs of boost. As time went on it was cleared to use 12lbs and then 15lbs and then 16lbs of boost. see:
http://www.wwiiaircraftperformance.org/Spitfire_V_Level_Speed_RAE.jpg

The cropped impeller engines gained power in three ways. It took less power to turn the impeller to get the same boost at low altitudes. The intake air was heated less (meaning it was denser at the same pressure.) and because of the cooler intake temperature more boost could be used before hitting the detonation limit. 




> This is from the wiki:
> 
> List of Rolls-Royce Merlin variants - Wikipedia
> 
> _Merlin 45M 1,230 hp (917 kW) at 3,000 rpm 1,585 hp (1,182 kW) at 3,000 rpm, +18 psi (124 kPa) boost, 2,750 ft (838 m) Spitfire LF Mk.V Version of Merlin 45 with "cropped" (smaller diameter) supercharger impeller allowing greater boost at low altitudes._



It is not "wrong" but it is misleading. At times the SPitfire V with the standard 45/50 engine was book limited to 3 minutes at the higher boost levels. the cropped impeller engines may have had a more lenient time limit?

The power needed to turn an impeller (and the boost made by the impeller) are proportional to the square of the impeller tip speed. soooooo...
the cropped impeller will take about 86% of the power to turn as the larger impeller and heat the intake charge proportionally less. Right up until you hit the flow limit.


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## Shortround6 (Dec 11, 2018)

tomo pauk said:


> Welcome back
> Now to the point - with P-40, it was very much about engine, too. In 1941-late 1942, Merlin 45 vs. V-1710-33 or -39 means at least 25% extra power for no gain in weight. For example, at 15000 ft, it is 1030 HP vs. 1300+. No ram.
> Come late 1942, Spitfire gets Merlin 61, P-40 gets an improved V-1710 - no contest at all, Spitfire's engine has more power at 25000 ft than P-40s at 15000 ft.


Yeah but you have to find somewhere to stick the intercooler for the Merlin 61 (or two stage V-1710) that doesn't use up a fair amount of the power in extra drag  

Plus you have several hundred pounds of extra engine weight.

Hooker certainly pushed the Merlin engine into a new catagory with both the new single stage and two stage superchargers.


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## wuzak (Dec 11, 2018)

Shortround6 said:


> The cropped impeller engines gained power in three ways. It took less power to turn the impeller to get the same boost at low altitudes. The intake air was heated less (meaning it was denser at the same pressure.) and because of the cooler intake temperature more boost could be used before hitting the detonation limit.



And because of the lower pressure ratio (boost) the throttle could be opened fully at a lower altitude (and could be opened wider than before at even lower altitudes) reducing pumping losses.


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## Shortround6 (Dec 11, 2018)

The P-40 was absolutely critical to the US and allies simply because it was there when needed, not because it was an under appreciated wonder plane with a bad press agent. 

The New Curtiss book started By Dean has an interesting production table of US fighters in 1940.

out of 1685 fighters built in US factories in 1940 (of 12 different types) Curtiss built 481 P-36/H75 Hawks and 778 P-40/H81As and 27 CW-21/CW-21Bs so Curtiss built over 75% of the US fighters in 1940. 
Republic built a total of 104 EP-1/P-35 and YP-43s (2) while Bell built 13 YP-39s and 11 of those twin engine Buck Rogers monstrosities. 
Brewster built 160 F2A/ 239/339 aircraft and Grumman built 103 F4F/G-36 export aircraft. 

Curtiss would go on to build 2248 P-40s in 1941 and 3854 P-40s in 1942 and while these numbers would be dwarfed by later US production they were the lion's share of production in 1941 and 1942. Waiting around for a "better" engine than the Allison or improved Allisons before building these fighters would have left the US and it's allies thousands of planes short in 1942. 

Please remember that many things changed with time. The Allison engine of 1940 was every bit as good as the DB 601 of 1940 and better than the French Hispanos and Russian M-100/M-105 series of engines and as good or better than the Italian and Japanese copies/developments of the DB 601. 

But saddling the P-40 with 900lbs of guns and ammo and accessories in the wing with the engines available in 1940/41 could only end one way ( and the planes were actually designed to hold an additional 140lbs of ammo).

Why this was done is subject to speculation but let's remember that the _service _.50 cal Browning of early 1940 was a 600rpm gun (if you were lucky) and not the 800-850rpm gun in would become in late 1940/early 1941 although reliability at the higher rates of fire left something to be desired in the early days. The guns didn't break but they seemed to more than a bit fussy about the feed arrangements. The types of projectiles _in service _in 1940 was also rather limited. What was being planned or how far along they were in development (and initial manufacture) is unknown but the target effect of a six gun battery of early 1940 .50 cal machine guns may be quite a bit lower than the target effect of six 1943 .50 cal guns. 
But like I said before, you can't go back in the field and make the wing smaller, fit lighter landing gear and tires, make the spars thinner and so on. You are stuck with the airframe built to take a 1/2 ton of guns and ammo. which is way more than even a Bf 109G-6 gun boat or even a FW 190 that had MG/FFM cannon in the outer wing. It was nearly as much as the guns and ammo in a Hawker Typhoon with four 20mm cannon.

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## Greyman (Dec 11, 2018)

Quick Spitfire graph to illustrate the Merlins;
*Merlin 45 (+16) - Merlin 46 (+16) - Merlin 45M (+18)*

*







*

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## Schweik (Dec 11, 2018)

tomo pauk said:


> Both Tempest and Typhoon were far better than P-40 at any altitude.



Once again you are missing my point. Tempest wasn't introduced to combat until 1944 so I would hope it would be better than a P-40 introduced in 1941. Typhoon I'm not so sure but I don't care enough to argue that point!



> Soviet fighters being good just at low altitude was a bug, not a feature. Ditto for their performance and range. MiG-3 was too ligthly armed by Soviet standards, used the engine produced at factories that were also supplying the Il-2 needs, the cockpit was so bad that pilots preferred to fly with open cockpit (hence killing lots of speed).



I don't think you understand the Soviet battlefield then. I'm sure in theory the Soviets would have welcomed the technology of the two stage supercharger, and they were eventually given Spitfire Mk IX's so they did undoubtedly have it. But why spend the extra steel, the rare materials, and added weight for an aircraft to fly 3 miles above the cloud ceiling over the actual battlefield? 

Much later, after the end of the war was a foregone conclusion, they experimented with high altitude fighters probably mainly in case the Americans decided to start sending heavy bombers into Russia in a continuation of the war, and to catch the occasional Ju 86..

In my opinion, later war Soviet fighters were perfectly adapted to the conditions they were needed for. Soviet planes were required to be small, cheap (especially in metals), simple to fly and agile enough to cover the front. They needed to protect the Sturmoviks that destroyed the panzers, and destroy the stukas, the jabos and the Hs 129s. The Germans weren't sending four engine heavy bombers to bomb the Russians and the Russians weren't sending any into Germany. The battle was at the front line.

That's why even the Spit IXs they got were relegated to PVO duties behind the lines. Important work no doubt, but not war-winning work for that Theater.





And that is why the Yak 3 and La 5 FN are widely considered two of the best fighters of the war certainly both better than P-40s, but more importantly, better than Bf 109s and Fw 1980s for where they fought, which was all that mattered... even though they were pretty much useless at 28,000'.





> In 1942, Zeroes were far better hi-alt fighters than P-40s, and Japan produced other fighters that were not Zeroes. Hurricane was a draggy affair, engine was able to help just that much.
> 
> There was a purpose.
> Please note that 1st and foremost people were trying to introduce 'all-altitude' fighters, and, once that was sattisfied, they introduced specific fighters for high altitudes and low altitudes. Unfortunately, there was no 'HF' P-40s or P-39s, due to V-1710 being about as good as Merlin 45M, altitude-wise.



In the long run, there didn't need to be. P-40s defeated the Zeros and the Hayabusas at Port Morseby, and Milne Bay, and above the Kokoda Trail, and over the Solomons. They drove them away from the cargo planes flying over the Hump in the Himalayas and along the Burma Road. They defeated them over their own armies in China and helped turn the tide of that land war. That is what really matered.


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## Schweik (Dec 11, 2018)

Shortround6 said:


> In reverse.
> 
> "_They were using external fuel tanks on P-40E from early on. Not sure about the D but a lot of the D models only had four guns_."
> 
> ALL of the Ds had 4 guns, but according to some sources there were only about 30 Ds (or 30 built for the US) built before the contracts were amended to E models so the point is rather moot.



Uh, no it's not - More P-40D and E were used in North Africa by the RAF and DAF Commonwealth units, where they played a very important role. It's not all about US use. Similarly most of the Tomahawks that saw combat were used by either the RAF / DAF or the Soviets.


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## Schweik (Dec 11, 2018)

The P-40D had a production run of 583 aircraft, 23 went to the US, 560 went to the RAF. Only the first 20 sent to the RAF had 4 guns, I think all of the American ones did. However some were used in the field (in North Africa) with four guns and some with six.

Of the P-40E, 8209 went tot he US, 1,500 went to the RAF of which a few hundred ended up in Russia and a few hundred ended up in Australia and New Zealand.



Shortround6 said:


> I love the bit about _tinkering_ the engines. Nobody ever says what was done. You can't do much with the timing. Allison ignition timing was fixed, there was no variable advance.



You are making a ton of assumptions here as to what I meant, why not just ask before you go off on a tangent? It gets weary spelling every single thing out and my posts are too long as it is but if I don't cover every possible nuance of what I mean I get this sort of thing. 

To clarify: I was just referring to over-revving the engines (reported by the Russians) and overboosting the engines. I believe this is what Australian P-40 double ace Bobby GIbbes meant when he said _"later when we got our Kittyhawks running properly - were getting better performance - they were a better aeroplane." _

The various strengthening measures to the crank shaft and crank case on the V-1710 were already being done as early as the -33 model and the peened crank shafts about midway through the -39 production run. As engines wore out (whether through abuse, battle damage, dust, tropical conditions, bad maintenance or whatever) they were often replaced with newer engines - some Kittyhawk Mk1 and Ia (P-40D and E) in RAF service flying in late 1942 apparently had V-1710-73 engines in them which contributed to some accidents on takeoff due to pilots not being used to the extra power. When the P-40Ks came out incidentally with automatic boost control many pilots had the throttles rewired to remove it so they could 'tinker' with the boost.



> Saying that early P-40Es could have been over boosted like the P-40Ks were given the different crankshaft and possibly different fuels is pushing things.



The famous Allison memo and the memo about the RAF use of the P-51A / Mustang I etc. both specifically mention the high overboosting being done with the V-1710-39 (i.e. P-40E) engines and US units were specifically mentioned in the Allison memo. The Allison memo also notes they had previously 'accepted' WEP settings of 60" Hg.



> Taking weight out helped but please look at the factory strippers. The Early P-40L and the Early P-40N. the chances of any squadron mechanics getting a P-40 pf any type down st.



We have been over this before. They took out fuel, fuel tanks, a pair of guns, and some armor that you don't think existed.



> 1/2 fuel mans what? 100 US gallons if you count the drop tank? 74 US gallons if you don't ? 60 US gallons (50 imp gallons) if it is 1/2 the "book" combat fuel load?
> A P-40E was going to use over 40 US gallons just starting, taking off and climbing to 20,000ft. Figure another 8-13 gallons to make it to 25,000ft.
> In combat the engine might use 1 to 1/2 gallons a minute at high altitude. (much more at lower altitudes).
> 
> Sorry, gliding back to the airfield after an intercept doesn't sound like that great of an idea. Reduced fuel yes but 1/2???



Actually from what I understand they sometimes took off with two guns and less than half fuel. Not just with P-40s they did it with Hurricanes too. I'm just repeating what the sources say they did.



> They were were overboosted but squadron records don't seem to show the failure rate. And the failure rate has to take into account the availability rate (number of planes grounded with metal bits in the oil waiting for an engine change) and not just the number of crashes due to engine failure. How many minutes/hours at how much over boost before engine failure?
> compounded by the crappy operating conditions. does the crankshaft fail from fatigue before or after the engine bearings are wrecked by sand/grit in the oil?



I'm sure they wrecked a lot of them, the new Shores book Volume IV shows a lot of engine problems and engine failures with the P-40Ls in particular. I don't think the pilots cared though.



> There was no "dance" between the manufactures and the military. In 1939-40 there was a change in what was required in military aircraft in many countries. Curtiss lost over $14,000 when the 2nd XP-46



I know we have had this debate before too and you side with the manufacturers, I'm not pitting one against the other in this comment, I'm just pointing out that the 

The issue was usually that the engines (in every country) took longer than expected by the aircraft designers to achieve the promised power output and the airframe inevitably had to carry more weight in fuel, ordinance, radios, batteries, fire suppression gear, armor and self sealing fuel tanks and other "unexpected" things which quickly put the plane over the tipping point. Manufacturers also had to do a fair amount of fine tuning which took a while to get the best speed out of a new airframe, and they were often struggling to reach performance benchmarks while trying to meet demands for extra gear. 

And then they were often stripped of extra things in the field by resourceful crews and the pilots themselves responding to battlefield conditions. Sometime that happens faster with a foreign aircraft. That is what the Finns did with the Buffalo and it's what the Russians and RAF and Australians did with the P-40. By the time Americans were engaged in the Med they followed suit.

For fighter vs. fighter combat incidentally I do think four .50 cal guns were enough, which is why it was standard for a while for P-40F pilots to remove two guns during the heaviest fighting in Tunisia - though part of the strategy developed by P-40 units in the Med, and to a lesser extent in the Pacific and CBI, to face attacking fighters coming from above was to turn into the attack all guns blazing - the Axis fighters whether German, Italian or Japanese usually gave ground first in the resulting game of chicken because it was just too many large caliber bullets heading their way at too high a velocity. If they didn't they usually went down.

S

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## Schweik (Dec 11, 2018)

wuzak said:


> 20,000ft is what would have been considered mid-altitudes.
> 
> The advantage a higher critical altitude engine is maintained at altitudes above that critical altitude, if not widening the gap.
> 
> ...



Well performance to a P-40F or L seems to be fairly close then because according to this September 1942 Ministry of Aircraft Production memo, P-40F was able to make 370 mph at 20,400 ft and 347 mph at 30,000 ft. So it wasn't a total wash.

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## Stig1207 (Dec 12, 2018)

fubar57 said:


> Thanks for the PDF


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## Stig1207 (Dec 12, 2018)

Schweik said:


> Well to be clear, I was talking about MAW IV which is May 43 to Sept 44, and certainly the air to air casualties went down as the flak casualites went way up in 1944 which you can see in the Air Force journal records.
> 
> If there is a difference, and I'm not sure there is, it may boil down to how things like air to air collisions, engine failure etc. are counted.
> 
> But I agree the month analysis would be good to do, it may take a while though it's very busy lots of fighting with numerous claims and losses on both sides. A lot of transcribing.



I've only had MAW IV a few days and I haven't got through June '43 yet, so I can't comment on anything about '44 yet 

However, it seems to me, that we both get the impression from MAW II and III that there are more USAAF fighters losses to flak than the Statistical Digest gives, so I think it's safe to say that there is conflicting information for 1943.


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## tomo pauk (Dec 12, 2018)

Shortround6 said:


> Yeah but you have to find somewhere to stick the intercooler for the Merlin 61 (or two stage V-1710) that doesn't use up a fair amount of the power in extra drag
> 
> Plus you have several hundred pounds of extra engine weight.
> 
> Hooker certainly pushed the Merlin engine into a new catagory with both the new single stage and two stage superchargers.



Intercooler can go in the wing, the XP-40 housed it's radiators there. Several hunderds pounds of extra weight was easily accomodated by Spitfire, Fw 190, P-51 and Bf 109 when new engines were added, the trade off was worth it. 



Schweik said:


> Once again you are missing my point. Tempest wasn't introduced to combat until 1944 so I would hope it would be better than a P-40 introduced in 1941. Typhoon I'm not so sure but I don't care enough to argue that point!



I care.
Typhoon was well able to compete with Fw 190 at 15000-20000 ft as it was the case for 5000-7000 ft, while P-40 was not capable on taking on Fw 190s at 15000-20000 ft.



> I don't think you understand the Soviet battlefield then. I'm sure in theory the Soviets would have welcomed the technology of the two stage supercharger, and they were eventually given Spitfire Mk IX's so they did undoubtedly have it. But why spend the extra steel, the rare materials, and added weight for an aircraft to fly 3 miles above the cloud ceiling over the actual battlefield?
> 
> Much later, after the end of the war was a foregone conclusion, they experimented with high altitude fighters probably mainly in case the Americans decided to start sending heavy bombers into Russia in a continuation of the war, and to catch the occasional Ju 86..



I'll stop ignoring the 'I don't think you understand' remarks any minute now.
2-stage engines don't require any rare materials above what it was usualy used on engines' superchargers. Soviets experimented with hi-alt fightes already in 1930s, adding turboes at I-16 for example, while in ww2 they were designing 2-stage supercharged versions of VK-105 (overheated alot, so they later added ADI; still produced in penney packets only), as well as with intercooled AM-37. Plus turbocharged MiG fighter prototypes, all of whose were to fight high flying German recons and bombers.



> In my opinion, later war Soviet fighters were perfectly adapted to the conditions they were needed for. Soviet planes were required to be small, cheap (especially in metals), simple to fly and agile enough to cover the front. They needed to protect the Sturmoviks that destroyed the panzers, and destroy the stukas, the jabos and the Hs 129s. The Germans weren't sending four engine heavy bombers to bomb the Russians and the Russians weren't sending any into Germany. The battle was at the front line.
> 
> That's why even the Spit IXs they got were relegated to PVO duties behind the lines. Important work no doubt, but not war-winning work for that Theater.



No problems with that.



> And that is why the Yak 3 and La 5 FN are widely considered two of the best fighters of the war certainly both better than P-40s, but more importantly, better than Bf 109s and Fw 1980s for where they fought, which was all that mattered... even though they were pretty much useless at 28,000'.



The La5FN managed to _barely_ emulate Fw 190A1 and Bf 109F-4 performance 2 years later, dito for Yak 3. Fighters that were useless at 28000 ft probably can't be considered when talking about best fighters, ditto for fighters that are inable to fly 400-500-600 miles away, fight well, and return the said amount of miles. All while having half of firepower of many Western or Japanese fighters



> In the long run, there didn't need to be. P-40s defeated the Zeros and the Hayabusas at Port Morseby, and Milne Bay, and above the Kokoda Trail, and over the Solomons. They drove them away from the cargo planes flying over the Hump in the Himalayas and along the Burma Road. They defeated them over their own armies in China and helped turn the tide of that land war. That is what really matered.



Those examples prove many other things (while I don't necessarily agree that P-40 actually won all of you've listed):
-side with better logistics & intel wins long, attrition wars
-wars are combined arms affair
-rarely, if ever, a silver bullet decides the outcome
-outnumbering the enemy has it's appeal

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## wuzak (Dec 12, 2018)

tomo pauk said:


> Intercooler can go in the wing, the XP-40 housed it's radiators there. Several hunderds pounds of extra weight was easily accomodated by Spitfire, Fw 190, P-51 and Bf 109 when new engines were added, the trade off was worth it.



The XP-40 had the radiator under the rear fuselage, but it was moved forward under the nose when it was found to not work very well.




Curtiss, XP-40, Model 75P by SDASM Archives, on Flickr

An XP-40K had the radiators under the wing centre section




Ray Wagner Collection Image by SDASM Archives, on Flickr


The size of the intercooler need not be huge



de Havilland DH98 Mosquito B.35 ‘TA634 / 8K-K’ (G-AWJV) by Alan Wilson, on Flickr

The intake under the spinner is for the intercooler, while the gills on either side of the nacelles just ahead of the carburetor intake are the outlets.


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## tomo pauk (Dec 12, 2018)

wuzak said:


> The XP-40 had the radiator under the rear fuselage, but it was moved forward under the nose when it was found to not work very well.



Whoops, my bad in nomenclature - the XP-40Q was the one with radiators in the wing.


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## Timppa (Dec 12, 2018)

Shortround6 said:


> I love the bit about _tinkering_ the engines. Nobody ever says what was done. You can't do much with the timing..You can change the jets in the carburetor...etc.
> Working on supercharged aircraft engines is a lot different than working on a 1940s Chevy six or Ford Flat head V-8.



Increasing the boost pressure, of course. The most effective way to increase power of supercharged engine.

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## P-39 Expert (Dec 12, 2018)

I think most of us will agree:

1. The P-40E was just too heavy to have good (or any) high altitude performance due to excessive weight. And there was no way to effectively cure this situation. Low, medium and high altitude being arbitrarily defined as under 10000' is low, 10-20000' is medium and over 20000' is high altitude. And not much combat at all was done over 8000 meters or 26500'.
2. Any engine should not be overboosted in ANY situation unless absolutely necessary for survival, they didn't call it WAR EMERGENCY POWER (and limit to 5 min) for nothing.
3. There were very few "low altitude" fighter planes manufactured as such. Air forces needed planes that could fight at all altitudes. As the war progressed and planes got engines with higher altitude capabilities the (normally older) lower altitude planes were relegated to lower altitude duty such as ground attack and escort of medium bombers/transports that flew under 15000'.
4. The P-40E did reasonably well in combat, but were normally employed in secondary theaters against lesser fighters past their prime. P-40Es didn't escort B-17s at 25000'.

The P-40 was not optimal but did yeoman's duty at a time when we had nothing else.

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## Schweik (Dec 12, 2018)

P-39 Expert said:


> I think most of us will agree:



Lol



> 1. The P-40E was just too heavy to have good (or any) high altitude performance due to excessive weight.



Considering that it was lighter than a P-51 I think this is demonstrably incorrect.



> 2. Any engine should not be overboosted in ANY situation unless absolutely necessary for survival, they didn't call it WAR EMERGENCY POWER (and limit to 5 min) for nothing.



Again,* incorrect*. The issue here is that what was originally considered WAR EMERGENCY POWER as you so exuberantly put it later became normal military power settings, usually as the result of such settings being tested in combat. These were in turn routinely used in P-40s for example for climbing to altitude, and for extended periods exceeding 15 minutes. We know that the original WEP setting for the P-40E as established by Allison was overly conservative at 45" Hg. We also know that this was later officially remanded to 56" Hg and then to 60" Hg, per Allison Aircraft corporation memos.

Aside from the Allison memo already posted in this thread twice (once by myself and once by another poster) I call your attention to this Air Force memo about the Allison Engined P-51. It reports that in British service, Mustangs using the same Allison engine that the P-40E had (V-1710-39) reported that they were able to run 20 minutes at 72" Hg without hurting the engine_ and_ averaging 1500 hours between failures. This had become their routine tactic when disengaging from daytime intruder raids over occupied France and Holland. The official rating of 45" was quickly left behind as it was a mistake, in fact it later became the new military power setting for Kittyhawks. Quoting directly from Brigadier General Charles F. Born:

_"This aircraft is powered with* the Allison 1710-39 engine having a rated power of 1150 H.P. at 3000 R.P.M. and 44” Hg. at 12,000 ft.* The engine was originally equipped with an automatic boost control limiting the manifold pressure at the lower altitudes to 44”. The British remove this so as to get the vastly increased performance at lower altitudes thru the judicious use of over-boost. _

_*In view of the British operation and the fact that we have an approved war emergency rating on the 1710-39 engine of 56”*, it is suggested that immediate steps be taken to remove the automatic boost controls from our P-51 airplanes in this theatre* and that the instrument dials be marked with the proper lights. * The British have operated at full throttle at sea level (72” Hg) for as much as 20 min. at a time without hurting the engines. According to them, the Allison is averaging 1500 hours between bearing failures* as compared to 500 to 600 hours for the Merlin. The Allison, they have found, will drag them home even with the bearing ruined. "_

* RAF and RAAF squadrons were removing automatic boost controls from Kittyhawks in 1942 for the same reason.

The only real debate here is how soon did they figure this out and how widely was it spread, did it require special (British) fuel etc.



> 3. There were very few "low altitude" fighter planes manufactured as such. Air forces needed planes that could fight at all altitudes. As the war progressed and planes got engines with higher altitude capabilities the (normally older) lower altitude planes were relegated to lower altitude duty such as ground attack and escort of medium bombers/transports that flew under 15000'.



Disagree as I have already pointed out in depth.



> 4. The P-40E did reasonably well in combat, but were normally employed in secondary theaters against lesser fighters past their prime. P-40Es didn't escort B-17s at 25000'.



Again, demonstrably *incorrect*. This seems to be another persistent myth related to the Med theater which we have alreeady discussed this at length in this forum. The Mediterranean and North African Theaters had recieved the best available German fighters as soon as they were available precisely because of problems older / lesser fighters (Bf 109E and Bf 110, MC 200 etc.) had dealing with earlier Tomahawk type P-40s. By Dec 1941 Bf 109F2s were on site, then Bf109F4s as soon as they were available, and by the time the Americans had arrived to join the fighting in Tunisia, Bf109G2 and G4, and then increasingly G6 (which were probably not as good as F4s actually but they were the newest)

If necessary I can post the TO&E of the Axis forces in the Med but I believe I already did post them in another thread here for some month, I believe Oct 1942, I'll see if I can find it.

Same for the Russian front which again, we debated here at length previously. The Germans were putting their best fighters into action in Russia and had converted over to the F2s and F4s by the time the Kittyhawks were in action.

And in the Pacific of course the Japanese were using their best aircraft - the latest A6M and Ki-43 variants, Ki-61 and Ki-44. In Burma, in another old thread on here someone posted data about successful engagements between P-40s and Ki-84s and some other late war Japanese fighters.



> The P-40 was not optimal but did yeoman's duty at a time when we had nothing else.



Can't disagree though it's a vague and rather meaningless cliche. You could say the same about basically every fighter - though they did have other options (like the P-39 and the Hurricane) but the P-40 turned out to be the most useful.

S

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## Schweik (Dec 12, 2018)

Here is an anecdote I had previously posted to another thread, which refers to overboosting in P-40F or L models, which according to the pilot enabled him to keep up with and then outrun Bf 109s he was facing. This is all directly from P-40 Aces of the Med (Osprey), page 16:

_Another 64th FS _[57th FG] _pilot taking part in the 9 October mission was 1Lt George D Mobbs, who had a much rougher time of it. He recorded this description in his diary:_

_'We got mixed up and got to the landing ground ahead of the bombers, but went in to strafe anyway. That is, most of us did. I was on the outside, and just as we started to go down, for or five '109s started to attack me. I turned into them and got a short burst at one, but it was a 90 -degree deflection shot. Three of them kept attacking me, and I kept evading them, and occasionally getting a shot. Meanwhile, the rest of our aeroplanes had gon in to strafe and then flown out to sea, but I couldn't join them because the three German fighters kept on attacking me._

_*I was running the engine at 55 to 65 inches of mercury and 3,000 rpm, so I could pretty well stay with them. *They would keep alternating the attacks between them. After a few minutes I got on one of their tails *and was overtaking him*. I didn't open fire until i was about 100 yards from im. I gave him a squirt and nothing happened. I moved over a little and changed my sighting, and on about the third burst his aeroplane burst into flames and fell off to one side. i was going to watch him go down so i would have a chance of getting credit for one destroyed, but one of the other jokers attacked so i was busy evading him. However, I spotted the first one moments later a few hundred feet below me, still spiraling down, but I never got another look at him after that._

_I was still in a hole. The other two kept attacking, one after the other. Later, I got a few shots at one from directly behind and slightly above as we were diving. I could see the aeroplane jerk each time I pulled the trigger but saw no debris or fire from it., and I was driven away by the other one. attacking. I must have hit the Jerry, because I never saw him again._

_Now I just had one to worry about, but on his next attack I finished my ammunition. He kept following and attacking, but with just him to worry about, I was making pretty good time back toward our lines. On another attack we met head-on, and I didn't think he fired his guns. I didn't see them, anyway, and i was already out of ammunition._

_We were down pretty low by then - 1000 ft - and the German ack-ack had opened up at me. But I was going so fast that they were shooting behind me. *I had everything forward. I was running awfully hard*, and the ack ack was getting pretty close to the Jerry behind me.* It was kind of amusing, becuase it looked as if I was going to make it back if my engine didn't quit. *We were so low that I could see the ack-ack gun emplacements below.'_

_In fact the engine in 1Lt Mobbs' P-40F did hold together and the Bf 109 gave up the chase. The American returned safely to base, where he was awarded one Bf 109 probably destroyed for the mission. Four days later, Mobbs recorded his first of four confirmed victories during a scrap with 20 Bf 109s over El Alamein._ "

I checked this incident in Shores MAW. From the previous anecdote, I concluded the following:

Based on the German records, Lt. Mobbs 'damaged' claim may have been a victory after all. Possibly making him an Ace since he had 4 confirmed later in his tour. Its hard to say for sure but Germans lost three fighters in that area at the same time - the victories may have been from RAF Kittyhawks. The other LW loss was later and in a different area.
This is a clear example of overboosting to 55" - 65" Hg. You can certainly understand why.
It sounds like he was alternating from 55" to 65", both settings would be considered WEP, and the fight appears to have lasted much more than 5 minutes though it doesn't indicate precisely how long it actually was.
He was able to hold his own fighting three Bf 109s from the elite JG 27 unit, possibly shoot at least one of them down and then outrun another.
From all this I conclude that using overboost, P-40F could outrun Bf 109F-4 (Trop) at low altitude
I also conclude P-40F was at least an even match with the Bf 109F-4 (Trop) at low altitude, maybe a little better.
German overclaiming is notable in both incidents and by a wider margin than Allied claims. 4-1 LW vs 2-1 for DAF on Oct 9, and 2-1 LW vs 4/3 DAF on Oct 13.
It is also possible that he was actually fighting MC 202s or that he made it all up. But considering that his victory 4 days later over another bf 109F-4 it seems to be legitimate and backed up by German records I doubt it.

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## Schweik (Dec 12, 2018)

I found the posts where I previously broke down all the activity for a specific month of combat in the Med, Oct 1942.

The combat numbers showing claims vs. actual losses for the month can be found here
The TO &E for both sides and more data for the month can be found here

Summary of the latter is as follows:

*DAF Fighters*
_(This is theoretical strength not counting aircraft down for maintenance / damaged etc.)_
336 fighters (155 front line fighters - including 48 Spit Vs and 107 merlin engined P-40s, 194 older fighters - Hurricanes and older P-40s, plus 32 fighter bomber only Hurricane IID)

Axis Fighters
*Axis Fighters *
_(German Data for August 1942 per Shores - this is supposed to be real on-hand air strength)_
Axis 515 fighters (307 front line Bf 109 and MC 202, 150 biplanes and 12 bf 109E Jabos, 46 Bf 110). Most of the heavy lifting though was being done by about 100 Bf 109s.

This includes specifically 76 Bf 109F-4 (plus ~ 12 in III./JG 53 and a few more in the Jabo Staffl) and 210 Macchi MC. 202

JG 2 (Fw 190A-3 and A_4) arrived on 16 November with a further 24 fighters.

So I think this shows that Axis Air Forces in the Theater were neither outnumbered nor using second rate fighters, hopefully helping to debunk that particular persistent myth.

S

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## Shortround6 (Dec 12, 2018)

Schweik said:


> The P-40D had a production run of 583 aircraft, 23 went to the US, 560 went to the RAF. Only the first 20 sent to the RAF had 4 guns, I think all of the American ones did. However some were used in the field (in North Africa) with four guns and some with six.



SO total production of 4 gun P-40D/Es was 43 planes and over half never saw combat? Like I said, the 4 gun P-40D is a moot point.
Except if you can find performance data for it to show any difference from the 6 gun P-40D/E. For the D the planned ammo went to 1000 rounds for 4 guns vs 1410 rounds for the six guns so the weight savings wasn't quite what you might think. They also made provision to hold up to 2460 rounds for the 4 guns so the planned max weights actually don't wind up very far apart. designed gross weight for a D being 7944lbs while a E was supposed to go 8011.5lbs, max gross was 8777.5 for the D and 8845lb for the E.
This is from the "Operation and Flight Instructions Handbook" of 1941. Designed gross weight was with 120 US gallons of fuel.



> You are making a ton of assumptions here as to what I meant, why not just ask before you go off on a tangent? It gets weary spelling every single thing out and my posts are too long as it is but if I don't cover every possible nuance of what I mean I get this sort of thing.
> 
> To clarify: I was just referring to over-revving the engines (reported by the Russians) and overboosting the engines. I believe this is what Australian P-40 double ace Bobby GIbbes meant when he said _"later when we got our Kittyhawks running properly - were getting better performance - they were a better aeroplane." _



I have to make assumptions when you use such vague terms as "tinkering". Over Revving and over boosting are NOT tinkering. They are abusing the engines and will shorten engine life and increase breakdowns. Going to 3200rpm instead of 3000rpm increases the stress on the reciprocating and rotating parts by about 13.7% since the increase in stress is proportional to the square of the speed. Over boosting is more liner. The factories were well aware of the increased forces involved.

I have tried to show that due to the changes in the engines and due to changes in the fuel the allowable boost could be increased over time (experience) to higher levels.
If you want to believe that such high pressures could have been used form the start regardless of fuel availability then nothing I can say will make any difference.



> We have been over this before. They took out fuel, fuel tanks, a pair of guns, and some armor that you don't think existed.
> 
> Actually from what I understand they sometimes took off with two guns and less than half fuel. Not just with P-40s they did it with Hurricanes too. I'm just repeating what the sources say they did./QUOTE]
> 
> ...


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## Schweik (Dec 12, 2018)

tomo pauk said:


> I care.
> Typhoon was well able to compete with Fw 190 at 15000-20000 ft as it was the case for 5000-7000 ft, while P-40 was not capable on taking on Fw 190s at 15000-20000 ft.



Lol Ok I'll start another thread to compare P-40 to Typhoon, I think I will be vindicated though I don't know the operational numbers for the Typhoon.

Which is the better low level fighter, P-40F or Typhoon?



> 2-stage engines don't require any rare materials above what it was usualy used on engines' superchargers. Soviets experimented with hi-alt fightes already in 1930s, adding turboes at I-16 for example, while in ww2 they were designing 2-stage supercharged versions of VK-105 (overheated alot, so they later added ADI; still produced in penney packets only), as well as with intercooled AM-37. Plus turbocharged MiG fighter prototypes, all of whose were to fight high flying German recons and bombers.



I think here is part of the nexus of our actual disagreement. Of course the Soviets would want to have the_ capability _to make high altitude fighters, just in case they needed it, and as I already pointed out before, they were given Spitfire Mk IX in 1943 so they undoubtedly could have reverse engineered two stage superchargers if they had felt it was a high priority. But I think it's clear that they didn't need it. The MiG-3 had good high altitude performance but was very disliked because of it's poor showing down low where all the real fighting was. Sure shooting down Ju 86s and higher flying medium bombers (which did do some serious damage early in the war) was good to have, but the main emphasis of the VVS was on coverage of ground operations at the front.

The cost of two stage engines in terms of materials may seem negligable from a Western perspective but Soviet aircraft design emphasized the use of as few as possible metals and any strategic materials including aluminum (which is why so much of so many of their fighters were made of birch plywood). Two stage engine means two impellers, possibly a whole second supercharger, plus an intercooler. That also undoubtedly increases maintenance costs. These things mattered to the Soviets - they would have done it anyway if they thought they needed a lot of high altitude fighters, but they clearly did not. There was routinely a cloud ceiling at 5,000 feet or less, and all the fighting that mattered centered around the tanks and Tactical ground targets. To wit...



> The La5FN managed to _barely_ emulate Fw 190A1 and Bf 109F-4 performance 2 years later, dito for Yak 3. Fighters that were useless at 28000 ft probably can't be considered when talking about best fighters, ditto for fighters that are inable to fly 400-500-600 miles away, fight well, and return the said amount of miles. All while having half of firepower of many Western or Japanese fighters



Well this is a German or Western oriented point of view that is a bit of an outlier - I think most WW2 aviation experts recognize that the Yak-3 was one of the superlative fighters of the war. The La 5FN was certainly considered such by the Soviets themselves, the Germans claimed not to think much of it, but I believe in terms of performance where it mattered, both aircraft outperformed their contemporaneous opposition to a sufficient extent that German aircraft casualty rates jumped up substantially in coincidence with their arrival. Of course the reasons would be debated - was it because of more aircraft or better aircraft or both? I would say the latter since numbers didn't make the difference when the Soviet pilots were flying I-16s and LaGG-3s. Soviet supply and maintenance situation did improve of course, while the German situation declined, but I don't think that is enough to explain it.

The bottom line is would a P-51 have been better for the Russian Front? I would say definitely not. The Spitfire wasn't either, clearly or they would have used it there instead of in PVO units. And arguably the best high altitude fighter they had, the P-47, was considered unsuitable for combat even for PVO.

S


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## Schweik (Dec 12, 2018)

Shortround6 said:


> SO total production of 4 gun P-40D/Es was 43 planes and over half never saw combat? Like I said, the 4 gun P-40D is a moot point.



You need to fix one of the quote tags on the second part of your post.


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## KiwiBiggles (Dec 12, 2018)

tomo pauk said:


> The La5FN managed to _barely_ emulate Fw 190A1 and Bf 109F-4 performance 2 years later


1941 performance in 1943? Undergunned by European standards? Sounds like the F6F to me.


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## Schweik (Dec 12, 2018)

I think it's much more just a difference in air combat philosophy. And incidentally, this is yet another reason why the Soviets liked the P-39. Take the wing guns off (as they did) and you have a fighter armed just like a mid-war Soviet fighter - armament in the nose, with a punch.

Soviet fighters were armed a lot like Marseilles era Bf 109s - relatively few guns all in the nose, for precision.

Is it better to shoot 1,000 .303 rounds from medium distance, or 700 12.7mm rounds to kill a target from far away or 15 cannon shells from right up close? Both approaches have their advantages, but the Soviets clearly liked the latter better for a variety of reasons and it did work.


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## Shortround6 (Dec 12, 2018)

Schweik said:


> The cost of two stage engines in terms of materials may seem negligable from a Western perspective but Soviet aircraft design emphasized the use of as few as possible metals and any strategic materials including aluminum (which is why so much of so many of their fighters were made of birch plywood). Two stage engine means two impellers, *possibly a whole second supercharger*, plus an intercooler.



2 stages means two superchargers, you can put both superchargers in the same basic "housing" or case but each impeller needs it's own diffuser and you need ducting/pipes so that the first supercharger dischargers into the intake of the second super supercharger. 





> Well this is a German or Western oriented point of view that is a bit of an outlier - I think most WW2 aviation experts recognize that the Yak-3 was *one of the superlative fighters of the war*. The La 5FN was certainly considered such by the Soviets themselves, the Germans claimed not to think much of it, but I believe in terms of performance where it mattered, both aircraft outperformed their contemporaneous opposition to a sufficient extent that German aircraft casualty rates jumped up substantially in coincidence with their arrival.


Or an honest appraisal?

The Yak 3 doesn't show up until until around D-Day. If you have a bunch of people saying the P-51 didn't show up until all the heavy work was done where does that leave the Yak-3? 
It is pretty much a one trick pony. If what you need is a short range low endurance dogfighter at under 12,000ft or so , then yeah, it is a pretty good fighter, if you need to do anything else then you are are out of luck. By low endurance I mean short combat persistence. You are out of ammo after about 13 seconds for the `12.7mm machine guns and the 20mm runs dry just before that. Not bad for 1941/42 but this is 1944. 
Russian 20mm cannon is *not* one of the wars finest. The gun itself wasn't too bad but the ammo was low powered, firing a light projectile of limited explosive power. 

It goes back to what the Russians were actually able to build, not what they wanted. With a Klimov VK-105PF engine you have to make some very definite choices as to what you want the fighter to do. Attempts to use higher powered engines (the VK-106 and VK -107) showed no results until after the war. Post war the availability of the much lighter Berezin B-20 cannon did increase the fire power even though it shortened the firing time. 

Russian views of the aircraft they used are no less biased that western views. Praising Western lend lease equipment too highly could get you a very, very long winter vacation. 
Two synchronized ShVak cannon on the LA-5 were hardly world class armament either, at least with 200rpg you didn't run out of ammo as fast as the Yak 3. 
Needing 2-3 aircraft to get the same amount of guns/ammo into the air as the Western planes is hardly brillant planning, even if it is good design given the available engines and fuel.

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## Schweik (Dec 12, 2018)

One other thing I forgot to add - 56" Hg on the V-1710 -39 in the P-40E apparently means *1,470 hp at sea level.* I don't know what the critical altitude is from there but that is pretty good performance down low, a _big_ jump from 1,150 and more than enough I would say to compensate for the weight of the airframe. Seeing as how they were routinely able to run at 72" (and 1780 hp) for 20 minutes, I would say it's a safe bet (though I do not have any direct proof) that they could run at 56" for at least that long and almost certainly did. But it still doesn't help at 15,000' let alone 25,000'.

P-40 pilots also mentioned using WEP for routinely climbing up to altitude, so it clearly wasn't that "extreme". I'll try to track down that quote and post it later.

Shortrun, I find it a little hard to read your post 225 due to the quote tag but I get the gist of your argument, and I acknowledge - we don't know precisely when, or where they started using higher power settings on P-40s. We do know they were using them in Australia and the Middle East by Dec 1942 but by then the P-40E is almost done as a frontline fighter. So this is the main thing left to find out about this whole issue IMO.

You seem to emphasize that field units wouldn't know how to handle all the necessary changes needed to get the better performance without wrecking engines or screwing up C.O.G. / balance and so on. I grant you that certainly the average high school educated mechanics probably did not have anywhere near the capabilities of Curtiss Inc engineers. What they did have was intense _motivation _since when the P-40E was introduced to combat in early 1942 it really had to hit the ground running as Allied air units in Java and the Philippines, in Moscow and Leningrad, in Egypt and Libya were under heavy enemy pressure and were basically getting slaughtered with their entire armies in existential crisis, and all Allied aircraft types suffering immense casualties. So presumably some of them found the expertise they needed somewhere and figured a lot of things out in very short order.

We know that various Allied Air forces stabilized a catastrophically bad situation in the early months of 1942 in large part using P-40s - specifically P-40D and E in that critical period (as well as Wildcats, Yak 1s, Hurricanes etc.), and we know at some point changes to engine operation and lightening of the aircraft were both part of the solution they found - along with new training and tactics and all kinds of other things.






Then P-40Ks that showed up in combat zones in mid 1942 were basically factory improved souped up P-40Es and they helped a lot - appparently in particular in Russia where several of the top P40 aces flew this specific subtype, as well as in the CBI and in the Pacific where you also see many Aces flying P-40Ks.

We also know specifically when it came to the Merlin engine P-40s the factory was catching up with the young mechanics at the front in modifying the P-40L to match the field modifications of the P-40F (which did, incidentally include removing the front wing fuel tanks). I agree removing 30 lbs of armor would not make a significant difference alone. But removing two .50 cal guns, 600 rounds of ammunition (P-40L loadout was 201 rounds per gun instead of 240-312 per gun, with six guns, of the factory issue P-40F), two rubber lined fuel tanks, and bomb shackles, and one of the radios, and some fuel,_ and_ thirty pounds of armor did make a difference as it apparently decreased the loaded weight down to 8020 lbs, which is a drop of 460 lbs from the standard loaded weight on the (six gun) P-40F.

S


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## Schweik (Dec 12, 2018)

Shortround6 said:


> 2 stages means two superchargers, you can put both superchargers in the same basic "housing" or case but each impeller needs it's own diffuser and you need ducting/pipes so that the first supercharger dischargers into the intake of the second super supercharger.



Gotcha, yeah that makes sense.



> Or an honest appraisal?
> 
> The Yak 3 doesn't show up until until around D-Day. If you have a bunch of people saying the P-51 didn't show up until all the heavy work was done where does that leave the Yak-3?
> It is pretty much a one trick pony. If what you need is a short range low endurance dogfighter at under 12,000ft or so , then yeah, it is a pretty good fighter, if you need to do anything else then you are are out of luck. By low endurance I mean short combat persistence. You are out of ammo after about 13 seconds for the `12.7mm machine guns and the 20mm runs dry just before that. Not bad for 1941/42 but this is 1944.
> ...



I can't really disagree with any of this. *I guess what Tomo and I are arguing about at this point is whether generalist aircraft are always better than specialized aircraft or not*. My answer would be "it depends."

For the Soviets I would say that specialized aircraft were what they wanted and I think they were correct. You are also correct that they were facing some severe limitations to their inline engines which is the reason emphasis started shifting somewhat to the radial engined La 5 / 7 / 9 series. And I agree the Yak 3 came out late, so did the Tempest and the Fw 190D. The La 5 series and Yak 9 undoubtedly mattered more to the Russian war effort, as probably even the P-39 - I mentioned the Yak 3 because it was so clearly (or so I thought) excellent.

Whether by accident or as was the case sometimes, on purpose, some aircraft - quite a few if you include the Soviet fighters, really ended up being specialized while others were more generally suitable to almost any Theater. The P-51 was the best generalized fighter the Allies had, arguably, in 1944, but for some purposes a Spitfire (basically a specialist interceptor) was better, for others a Yak 3 was (in my opinion) obviously better even though it was a specialized low altitude air superiority fighter.

The relevance was that while versatility was a big part of what was good about the P-40, it was also a specialist for low altitude (early marks) and medium altitude (later versions). And that was Ok because for several major Theaters of great importance to the overall war effort, down low was where the action was.

S


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## Schweik (Dec 12, 2018)

I should also add, I think just comparing simple measurements like top speed (which is inevitably at higher altitude since that is where aircraft flew fastest) or number of guns as some kind of indication of effectiveness is extremely misleading. A MiG 3 was 30 mph faster than a Yak-1b but the latter was much more valuable to the Russian war effort and a pilot flying the Yak had a much better chance of survival. Hurricane IIC was much more heavily armed than a Yak-1 but the latter was a much better fighter. Similarly a Bf 110 had a lot more guns than a Yak 3 but most likely was in big trouble in a fight with one regardless.

The Soviets had their biases just like the West did, but I don't think they were necessarily wrong in terms of aircraft design for their own Theater of war.

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## Greyman (Dec 12, 2018)

Schweik said:


> "_I was running the engine at 55 to 65 inches of mercury and 3,000 rpm ..."_



I think this is equivalent to the normal +12 to +16 lb boost that the Merlin XX series used for combat power.



Schweik said:


> One other thing I forgot to add - 56" Hg on the V-1710 -39 in the P-40E apparently means *1,470 hp at sea level.* I don't know what the critical altitude is from there but that is pretty good performance down low ...



I have 1,550 hp up to 4000 feet, which probably translates to a critical altitude of about 7,000 feet.

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## Schweik (Dec 12, 2018)

Greyman said:


> I think this is equivalent to the normal +12 to +16 lb boost that the Merlin XX series used for combat power.



According to my source it's rated at 1,300 hp with 54" Hg for takeoff, and 61" for WEP. Do you have some online source for those numbers? Is there a table somewhere converting lbs boost to inches of Hg? I'm still getting up to speed on the Merlin engines.



> I have 1,550 hp up to 4000 feet, which probably translates to a critical altitude of about 7,000 feet.



Critical altitude at that level of boost? I think critical altitude for the engine overall was ~12,000 ft.


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## Shortround6 (Dec 12, 2018)

Schweik said:


> I should also add, I think just comparing simple measurements like top speed (which is inevitably at higher altitude since that is where aircraft flew fastest) or number of guns as some kind of indication of effectiveness is extremely misleading. A MiG 3 was 30 mph faster than a Yak-1b but the latter was much more valuable to the Russian war effort and a pilot flying the Yak had a much better chance of survival. Hurricane IIC was much more heavily armed than a Yak-1 but the latter was a much better fighter. Similarly a Bf 110 had a lot more guns than a Yak 3 but most likely was in big trouble in a fight with one regardless.
> 
> The Soviets had their biases just like the West did, but I don't think they were necessarily wrong in terms of aircraft design for their own Theater of war.



WW II was a period of very fast development in aircraft of all types. What was a perfectly good fighter (even if not great) in one year was a deathtrap two years later in some cases.
By picking and choosing either fighter types or models of certain fighters you can come to some rather strange conclusions or prove a point if not looked at too closely. 
The Mig 3 was in service well over a year before the Yak-1B, being in actual fact the most modern fighter available in large numbers when the Germans attacked in in the summer of 1941. Neither the Yak 1 or Lagg-1/3 being available in numbers in operational units as opposed to numbers built/still in depot. 
The Mig 3 paid for it's high altitude performance by having light armament. The AM-35 engine would not take a gun through the prop hub so all three machine guns were synchronized. 
The Am-35 engine was a big beast and weighed around 550lbs more than the KV-105 engines used in the Yaks and Lagg-3. It weighed several hundred pounds more than any Merlin or DB605 engine and 400-500lbs more than an Allison or Merlin 45 or DB 601. With only 188 sq ft of wing something had to go to accommodate that big engine.

The KV-105PF engine used in the Yak-1b (and indeed most of the later Yaks) was a late 1942 development/adaptation. Of the 3,474 Yak-1s built in 1942 according to one source, 959 were the version with the KV-105PF engine. 
On the 5th of Dec 1941, just before the Russian counter attack near Moscow there were only 83 Yak-1s serving in VVS combat units and of those only 47 were operational. The Yak was being built in very large numbers at this time and numbers increased by hundreds per month.

You might want to reconsider using the Hurricane IIC as a bench mark as it was in production in the early Fall of 1941, It would also come close to it's "book" numbers unlike many of the early Russian aircraft. "improved" Yak-1s of late 1941 using the M-105PA engine and fitted with such refinements as a radio were good for about 347mph at at 15,750ft (4800 meters) and took 6.8 minutes to reach 5,000 meters (16,400) which is about 1 minute more than the earlier, even more spartan Yak 1s. Hurricanes tended not cover their own windscreens/canopies with oil for the engine or prop reduction gear, a major fault of the early M-105 engines. 

After a 1/2 year in service an assessment concluded that the Yak 1 had a great many defects, but they were not as a dangerous as the defects in the Mig-3 nor impair flying as much as the ones in the Lagg-3
The functioning of the landing gear was unsatisfactory, being not smooth and prone to sticking in intermediate positions and not fully retract. It also tended to fold up on landing.
Many pilots considered the armament too light and it often seized during firing, heat in the cockpit the already mentioned oiling of the windscreen and canopy made flying difficult.
Standard armament for the Yak-1s in the early part of the war was either one 20mm gun and two 7.62mm machine guns or one 20mm and one 12.7mm machine gun. 

If I was tasked with shooting down german twin bombers in 1941 there is little doubt that the Hurricane II would be the better choice even if it wasn't as good against 109Fs.
But then only a small percentage of the Russian Mig 3s, Lagg-3s and Yak 1s stood much chance against the 109F. 

While the advent of the 105PF engine improved things not everything was not a bouquet of roses, trying to upgrade existing planes didn't go well. They tried increasing the boost on M-105P or PA engines with a few modifications done in the field, however the increase power levels were more than the cooling systems could handle. In hot weather with the radiator intake closed for max speed the engine overheated within 2 minutes at the higher boost ratings. A boosted climb was also impossible without one or more periods of level flight to cool off the engine. Leaking oil also tneded ot clog up the radiator and oil cooler causing further cooling problems. They tried reducing the rpm while keeping the increased boost but any performance advantage was lost. The final PF engines used stronger wrist pins in the pistons, stronger engine blocks, bigger carburetor jets and the aircraft were fitted with a larger oil cooler. cooling was still critical. 

Timing is everything and while the YAK series was finally developed into a good serviceable aircraft the early ones had a bunch of problems that affected their combat performance.
Even in mid 1942 the quality of Russian optical guns sights was such that the pilots requested a return to the ring and bead sight system, which was granted. . 

What makes a good fighter is certainly more than just top speed or the number of guns but all fighters were far from equal in their subsystems and reliability. 
IN regards to gun power Wiki says that a Yak 1 with a single 20mm and a single 12.7mm mg could put out 4lbs of projectiles per second. A Hurricane II C could put out about 11.4 pounds in one second.
The Hurricane would run out of ammo faster

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## Shortround6 (Dec 12, 2018)

Schweik said:


> According to my source it's rated at 1,300 hp with 54" Hg for takeoff, and 61" for WEP. Do you have some online source for those numbers? Is there a table somewhere converting lbs boost to inches of Hg? I'm still getting up to speed on the Merlin engines.



Greg has posted a conversion chart that covers all systems of measurement. however a rough and ready conversion is to take the number in inches (say 54) and subtract 30 ( standard air pressure is 29.92in at 59 degreeF) giving 24 and then divide by 2 to get 12 pounds of boost (boost is the amount over standard air pressure). it can be a little off but should put you close enough. 






> Critical altitude at that level of boost? I think critical altitude for the engine overall was ~12,000 ft.



any engine is going to have multiple "critical altitudes" depending on the allowable boost limits. Critical altitude was originally the altitude for a single speed supercharger that the throttle could be fully opened without wrecking the engine. Merlin III being a case in point, at 16,250 ft the supercharger would give 6lbs (or close 1/4lb?) with the throttle fully opened *and no assist from the high pressure air in the intake duct due to forward speed. *
Below 16,250 ft the the throttle had to be closed to prevent overboosting the engine and causing detonation with the 87 octane fuel in service.
A Spitfire has a higher FTH ( Full throttle height) than either a Hurricane or Defiant, which used the same engine in level flight because it's higher speed creates a higher pressure in the intake duct leading to the carb and supercharger.
With the introduction of 100 octane fuel ( actually 100/115-120) the Merlin III was allowed to use 12lbs of boost and the throttle could be fully opened at 9,000ft for 1310hp.
Now please note that as the plane goes lower the throttle has to be progressively closed, wither by the pilot or by an automatic pressure control device/system and this partial blockage of the intake introduces losses. The extra churning of the air ( the impeller is fixed in speed to the crankshaft speed here) also heats up the air more and introduces losses (and dangers ) of it's own.
Throwing caution (and engine longevity) to the winds the Merlin III in the Sea Hurricane (often launched from catapults on a one way trip) was allowed to use 16lbs of boost and had a FTH of 5500ft and made 1440hp at that height.

So what was the FTH or critical height of the Merlin III?
A Spitfire doing 350mph or so could maintain the 6lb boost figure to about 18,000ft instead of the 16,250 of the test house figures just to confuse things and a Hurricane would a bit lower.

A Merlin XX or Packard V-1650-1 is going to have a different critical height for each supercharger gear.
In low gear for 9lbs boost (48 in) it was 11500ft for 1240hp with no assist from RAM and in high gear it was 18,500ft for 1120hp with no RAM. extra 120 hp at the lower altitude at same rpm and manifold pressure is due to less power going to the supercharger, the cooler (denser) intake mixture.
Yes it is rated at 1300hp for take-off at 12lbs (54in) but that is with the throttle part closed. 

Please note that the Merlin XX used a different less restrictive and more efficient supercharger inlet than the Merlin III which makes direct comparison difficult.

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## Schweik (Dec 12, 2018)

Shortround6 said:


> WW II was a period of very fast development in aircraft of all types. What was a perfectly good fighter (even if not great) in one year was a deathtrap two years later in some cases.
> By picking and choosing either fighter types or models of certain fighters you can come to some rather strange conclusions or prove a point if not looked at too closely.
> What makes a good fighter is certainly more than just top speed or the number of guns but all fighters were far from equal in their subsystems and reliability.
> IN regards to gun power Wiki says that a Yak 1 with a single 20mm and a single 12.7mm mg could put out 4lbs of projectiles per second. A Hurricane II C could put out about 11.4 pounds in one second.
> The Hurricane would run out of ammo faster



All very interesting but aside from the weight of the MiG-3 engine (interesting!) none of that is new to me. All the Russian fighters had serious production problems early on, they had to move nearly all the factories for one thing, some of those fighters were being made under the open sky. Ramping up to production was a nightmare even without the German Army and He-111s bombing...

For the record, I mentioned Yak-1B specifically rather than just Yak-1 because I was able to look up the speed for it very quickly (wikipedia) in order to make the point, which in case you forgot was that being fast alone wasn't guarantee of being a better fighter. The -1B may have been later than the MiG but the Yak-1 wasn't, they were contemporanous in fact the MiG-3 came out a bit later.

If you are really trying to suggest that a Hurricane IIC was better in Russia than the Yak-1 I think you are wrong, and you have a lot of Russians to argue with!

Seemingly every Russian who flew the Hurricane on the Russian Front hated it and it had a miserable record in Russia. No doubt it played it's role early on when they had little more than I-16s and I-153s and a few LaGG to play with, but there is no doubt in my mind that a Yak-1 was a better fighter for low altitude combat than any Hurricane.

As for many guns vs. few guns - almost every German pilot who flew them said the Bf109F was the best of the messers but it also had some of the lightest armament. Much, much less than a Hurri IIC, but does anyone argue for the latter in a dogfight?


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## michael rauls (Dec 12, 2018)

I think the Warhawk is a really under-appreciated fighter. When one considers the design dates back to 1935( the warhawk is still a hawk even after a new type of engine just as much as a fw 190d is still a fw 190 even with a new type of engine or a Mustang is still a Mustang etc.) and that it remained in front line service in all theaters and reasonably effective right up until the end of the war is, I think, truly remarkable. Not" 2nd string" or " noteworthy because its all we had in numbers at the time of our entry into the war"or any of the other disparaging characterizations we often read about it.
Was it as good as designs that came into existence 7 or 8 years later( which was a lifetime considering the accelerated pace of development at the time)? No of course not. But then again the p51 was not as good as a F86 either.

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## wuzak (Dec 12, 2018)

michael rauls said:


> I think the Warhawk is a really under-appreciated fighter.



I dunno. All this effort on behalf of the P-40 has me starting to think it is overrated.




michael rauls said:


> When one considers the design dates back to 1935( the warhawk is still a hawk even after a new type of engine just as much as a fw 190d is still a fw 190 even with a new type of engine or a Mustang is still a Mustang etc.) and that it remained in front line service in all theaters and reasonably effective right up until the end of the war is, I think, truly remarkable. Not" 2nd string" or " noteworthy because its all we had in numbers at the time of our entry into the war"



The P-40 never served in front line units in the ETO, certainly not throughout the war.

P-36s served in the Battle of France, but not after that in the ETO.




michael rauls said:


> Was it as good as designs that came into existence 7 or 8 years later( which was a lifetime considering the accelerated pace of development at the time)?



The Spitfire was a very near contemporary of the P-36 (first flight less than a year later) and it also served to the end of the war. 

And, generally speaking, it didn't seem that the P-40 was ever rated as highly as the Spitfire.

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## michael rauls (Dec 12, 2018)

wuzak said:


> I dunno. All this effort on behalf of the P-40 has me starting to think it is overrated.
> 
> 
> 
> ...


There were at least 3 RAAF units still flying P40s out of the northern tip of Italy on VE day. The 450th the " desert harassers" is the one I remember off the top of my head but there were at least 2 more and I have read there were a few others but not 100% sure about those. I think Italy qualifies as Europe.
Yes I would rate the Spitfire as a better fighter of the same aproxamite vintage but that doesn't mean the Hawk wasn't a remarkable plane considering the timeframe of it's introduction. It means that the Spit was remarkable and then some.
The p40 did have a few advantages that were important in some theatres for some missions but yes if the p40 was a great design considering its vitage ( and I think it was)then even more so the Spitfire. I would agree with that but dont think it takes away from the p40 at all.

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## Schweik (Dec 13, 2018)

wuzak said:


> I dunno. All this effort on behalf of the P-40 has me starting to think it is overrated.



Lol you aint foolin anybody mate, you've been anti-P-40 since day one

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## Schweik (Dec 13, 2018)

michael rauls said:


> But then again the p51 was not as good as a F86 either.



I think this is kind of the crux of the debate. It's similar to why people don't give props to the Hurricane or the A6M or the Ki-43 as well, pretty much any plane that wasn't still in the front ranks in 1945 is relegated to second tier status and disparaged, while fighters which flew in two squadrons for 9 weeks (Ta 152?) get praised to high heaven. Even though they were already obsolete because of jets, and didn't necessarily even rise above their more mundane opposition.

It's like if you didn't win the World Cup you never knew how to play football!

Not that there is anything wrong with liking end of the war fighters, they are cool and interesting too, I just don't buy the implication that everything that came before was somehow "lesser". Was a Fokker Dr.1 or a SPAD 13 a bad plane because it couldn't hang with an Me 262? Each great plane had their era and their moment, most only for a year or two in combat - _if_ they were unusually good designs. I think you can have more fun with history if you drop the cliches and embrace the variegated strangeness of each moment for it's own logic. There was a time when the Cr 32 was one of the best fighters in the world, and there was a time when Gloster Gladiators made them look bad... and then Mc 200s made _them_ run for the hills and so on.

To be honest though before I started really looking into the P-40, largely as the result of some of these kinds of discussions, I really didn't realize how good the record of that plane really was and for how long. Certainly the conventional wisdom leaves a lot out. I would still say the Spitfire was a better fighter overall, especially since the late versions continued to be so good all through the war. I'm not sure some of the other famous "best of the best" were as unbeatable as some claim. But most of them did have their day.

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## tomo pauk (Dec 13, 2018)

Again, plenty claims and counterclaims, so I'd just toss my 2 cents.

Germans certainly weren't of opinion that 1 cannon + 2 MGs in cetreline are end of discussion, since we know that they were attaching extra cannons on Bf 109 even at theaters where 4-engined bombers were not that often used, like at Eastern front, or MTO. Galland criticized the Bf 109F because it sported half the number of cannons vs. 109E, while no-one said: 'lets leave Fw 190s on just two cannons' armament' anywhere.
Soviets were also not sattisfied with firepower of their fighters, the MiG-3 got gun pods or rockets (for air combat), Yak-9T and LaGG-3-37 got 37 mm cannon, again for air combat. La-7 got 3 cannons instead of two once B-20 was available.
Not every pilot was Hartmann or Poryshkin.

Boost conversion graph, courtesy of krieghund:

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## Shortround6 (Dec 13, 2018)

michael rauls said:


> I think the Warhawk is a really under-appreciated fighter. When one considers the design dates back to 1935( the warhawk is still a hawk even after a new type of engine just as much as a fw 190d is still a fw 190 even with a new type of engine or a Mustang is still a Mustang etc.) and that it remained in front line service in all theaters and reasonably effective right up until the end of the war is, I think, truly remarkable. Not" 2nd string" or " noteworthy because its all we had in numbers at the time of our entry into the war"or any of the other disparaging characterizations we often read about it.
> .



from a test conducted at Eglin Air Force base Florida 7 June 1943


FINAL REPORT ON 
TEST OF OPERATIONAL SUITABILITY OF P-40N-1 AIRPLANE 

a. In speed, maneuverability, and rate of climb up to approximately twenty thousand (20,000) feet the P-40N-1 is the best of the P-40 series tested to date. While the P-40N-1 is the superior in performance of the P-40 series, it is generally inferior to all other current types of fighters tested at this station.

b. The P-40N-1 is of a design which is believed to have reached its limit in performance unless major changes in control surface design, wing form, structure and horsepower are made.

rest of it can be found here. http://www.wwiiaircraftperformance.org/P-40/P-40N_Operational_Suitability.pdf

thanks again to Mike Williams. 

This tells us most of what we need to know about how the USAAF felt about the P-40 with several years left of war ahead. 

The P-40 was considered by the AAF to be 2nd rate almost from the start. It was ordered in numbers in early 1939 because it was the only plane that could be produced in numbers in 1940/41 that wouldn't have been 3rd rate (or no planes at all had the Americans entered the war early). 

Now some of the planes that were supposed to replace it fell on their faces, some of the engines that were supposed to replace the Allison also fell on their faces and some of the Armies more advanced concepts (pusher fighters) couldn't even make out of a chair to fall on their faces. So the P-40 soldiered on. 

In some cases it was able to stay in service because it's enemies also failed to develop (or mas produce) more effective fighters and engines. In some cases it was handed out like candy to any and all nations that could scrape up a dozen or so pilots to join the allied cause (obvious exaggeration but it was used by over 20 nations, next to none of them paid for the P-40s) 

having enemy development programs fail is not evidence of good planning/procurement on the US end of things. Fortunate yes, evidence of superiority? no. 

In the Med the Italians were powering their planes (the ones with V-12) with a licenced 1939/40 DB 601 running on 87 octane fuel. A pretty poor combination in 1942/43. 
Had the Italians been been able to use even 1/2 of the improvements of the DB601E (forget the DB605) then their aircraft would have performed much better. 

In the Pacific or CBI the Japanese use of the Ki-43 from 1943 on was a total fail of planning and procurement. However good it was in 1941/43 making thousands in late 1943/44 was pretty much a waste of resources. 

The P-40 wasn't a bad plane, the US was just fortunate that we had so many better ones (to go along with some of the epic fails) that spending resources on the P-40 (and P-39) in 1944 was pretty much a mistake.


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## Schweik (Dec 13, 2018)

Shortround said:


> This tells us most of what we need to know about how the USAAF felt about the P-40 with several years left of war ahead.



That report is one of many which created the postwar legend of the P-40. The USAAF hated the P-40 as you say almost from the beginning of the war. As soon as they learned that enemy planes flew higher and faster, and even more so once the "Bomber Mafia" achieved ascendancy in the service, and Curtiss Aircraft screwed up again and again, they were no longer in favor and neither was the Hawk family of fighters any more. The legend that the P-40 was a 'dud' was firmly in place by 1943 and was heavily reinforced in the postwar Truman Commission hearings when Curtis Aircraft was being investigated.

But lets review the history of how this has evolved for a moment.

The Trope about the p-40 that it was "slow and unmaneuverable" but "rugged and cheap" was created in memos like that. I believed it too, the only exception to the rule in fact was the AVG legend which had it's own inertia. But the two stories dovetailed. The latter made the plane popular (along with it's looks and shark mouth paint) drawing a lot of interest in the fighter which "those in the know" cheerfully debunked. AVG had success, we were told, because the IJA only had Ki 27s to face them.

Over time however data started to leak out that undermined the Trope. Swimming heavily against the current of supposed "expert" opinion several WW2 fighter pilots from the US (like Erik Schilling of the AVG, General Benjamin O Davis of the 99th FS / Tuskegee airmen, Philip Adair of the "Burma Banshees", and double Ace Robert DeHaven of the 49th Fighter Group) and UK and ANZAC nations (like high scoring aces Clive Caldwell and Billy Drake) pointed out that they did well with the fighter and thought well of it. Some writers took note of the dozens of aces on the type. But the Trope still held for the most part. I personally witnessed some debates between aviation writers like Dan Ford and AVG pilot Erik Schilling which were downright embarrassing. Disrespectful to that bright and intelligent war veteran.

In 1990 Jeff Ethell reversed his previous opinion in a now famous video in which he described the P-40 as "a pitts with an Allison" and noted that it was _much_ more maneuverable than a P-51 (which he compared to a block of cement in comparison). Up to that point, and for long after it was still conventional wisdom from "experts" that P-40's were sluggish and unmaneuverable.

A big crack in the legend came when some of the Russian wartime records became available in the 'oughts and in interviews with many Russian pilots (like Nikolai Golodnikov) who had flown the plane in combat (as well as many others) pointed out that it was the equal of the Bf 109 to the end of 1943. Japanese records became available, and a compilation of records from the CBI came out showing that the 23rd Fighter Group and others continued the success of the AVG right to the end of the war. New Zealand pilots pointed out their record with the plane was excellent. A few hotly debated incidents with USAAF pilots in the Med emerged showing success against Bf 109s but Luftwaffe fans rationalized or minimized these as much as possible.

Then in 2007 one writer from Australia named Russel Brown wrote a book called _Desert Warriors_, which started checking the actual records of victories and losses. He pointed out that not of all of the experten's claims could be matched to actual Allied losses. He verified the claims of some of the stand out P-40 Commonwealth aces who actually shot down and killed several of those same experten.

And now Christopher Shores and his colleagues have done the very hard work of comparing German, Italian, RAF and American records to give us something pretty close to an accurate count of actual claims and losses in the Mediterranean. The successes of the USAAF P-40 fighter groups in particular has been an ongoing surprise to me, and has continued to change my perception of that fighter. I had assumed it had it's moment mostly in 1942, but I can now revise that and agree with the Soviet pilots who flew it that this fighter was well capable of shooting down any axis fighter right into 1944, and not just on a "once in a blue moon" fluke. And then this year I learned about the raw numbers, over 2200 victory claims in the hands of US pilots, 250 by ANZAC forces in the Pacific and at least 450 by DAF Commonwealth pilots in the Med / Middle East. That ads up to a substantial toll of enemy planes even when you account for overclaiming.




In my opinion, we are about due for a substantial re-evaluation of the aircraft. It's now widely understood that it was a maneuverable, one of the more fast rolling and tight turning fighters of the Allied side (after the Spitfire) but I think it's assessment still lags considerably from the evidence. It certainly wasn't the greatest plane of the war but it was hardly the dismal "also ran" that it gets habitually labelled as by people who should know better at this point.

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## Schweik (Dec 13, 2018)

I should say _some_ Japanese records became available. We still don't have full access to those if they even exist. And I've still never been able to find Soviet claim / loss lists by aircraft type though there are some tidbits in the Black Cross / Red star series.


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## Milosh (Dec 13, 2018)

Fw190 claims Tunisia - Sicily, Nov 8 1942 to May 13 1943

Spitfire - 73
P-38 - 41
P40 - 28

These were the major types claimed.

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## Schweik (Dec 13, 2018)

Milosh said:


> Fw190 claims Tunisia - Sicily, Nov 8 1942 to May 13 1943
> 
> Spitfire - 73
> P-38 - 41
> ...



Thats cool as hell what is the source?


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## Milosh (Dec 13, 2018)

Fw190 losses, date/location per previous post

<5% - 110
5-30% - 30
31-60% - 70
61-100% - 121

Source: Focke-Wulf in North Africa

More Luftwaffe claims for most theaters, http://don-caldwell.we.bs/jg26/claims/tonywood.htm

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## Schweik (Dec 13, 2018)

Milosh said:


> Fw190 losses, date/location per previous post
> 
> <5% - 110
> 5-30% - 30
> ...



Sorry - I don't know what I'm looking at there, what do those numbers above mean? Thanks for the link and the book name.


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## Milosh (Dec 13, 2018)

The Luftwaffe used a % damaged. Over 60% was a write off. The Brits used a Category - A, B, C, D, E.


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## Schweik (Dec 13, 2018)

Milosh said:


> The Luftwaffe used a % damaged. Over 60% was a write off. The Brits used a Category - A, B, C, D, E.



Oh yeah gotcha ok so those are all the Fw 190 losses


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## wuzak (Dec 13, 2018)

Milosh said:


> Fw190 claims Tunisia - Sicily, Nov 8 1942 to May 13 1943
> 
> Spitfire - 73
> P-38 - 41
> ...



If I understand correctly, these are Fw 190s claimed shot down by Allied fighters?

Not Allied fightes claimed by Fw 190 pilots?

I ask because, to me, the way it is worded isn't clear.


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## Schweik (Dec 13, 2018)

wuzak said:


> If I understand correctly, these are Fw 190s claimed shot down by Allied fighters?
> 
> Not Allied fightes claimed by Fw 190 pilots?
> 
> I ask because, to me, the way it is worded isn't clear.



I thought it was FW 190 claims of victories against Allied fighters but maybe you are right... it might be the "self reported" type that shot them down as the Germans indicated this in their records.


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## wuzak (Dec 13, 2018)

Considering the next post was about how the Germans classified Fw 190 losses and damages, I think it is the claims of Fw 190s shot down by Allied fighters.

If it was Allied fighters shot down by Fw 190s, there could be some bias in the claims towards the Spitfire over the P-40, in the same way that Hurricanes shot down in the BoB were often claimed as Spitfires.


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## Schweik (Dec 13, 2018)

wuzak said:


> Considering the next post was about how the Germans classified Fw 190 losses and damages, I think it is the claims of Fw 190s shot down by Allied fighters.
> 
> If it was Allied fighters shot down by Fw 190s, there could be some bias in the claims towards the Spitfire over the P-40, in the same way that Hurricanes shot down in the BoB were often claimed as Spitfires.



Yes there was a lot of mis-identification particularly with victory claims, though strangely, when they indicated who shot them down they were more often correct.

So it doesn't necessarily correlate to reality, but the ratios look about right to me.

The Spitfires took the lead in Air Superiority by 1943, and if you count both RAF and the USAAF Spit squadrons there were a lot of them. P-38s were also heavily involved in the air to air fighting. P-40 units probably claimed about 3 or 4 times that many Fw 190s all told but overclaiming ratios were about 2 or 3 times the actual losses typically (it varied by unit and by day) and just as the Germans tended to assume every hurricane was a P-40 and every P-40 was Spitfire, American pilots seemed to think a lot of Me 109s were Fw 190s. Probably half of their claims were actually Messerschmits.

So 28 Fw 190s lost to P-40s doesn't sound way off.

But he could also mean Fw 190 claims against Allied fighters as I originally thought so I should probably wait for him to clarify ...


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## Kevin J (Dec 13, 2018)

wuzak said:


> I dunno. All this effort on behalf of the P-40 has me starting to think it is overrated.
> 
> 
> 
> ...



The Tomahawk was operated by the RAF in 1941/42 over France for taking photos. It was faster than the Spitfire Vb below 15000 feet, but most fighting took place higher up so it was unsuitable as a fighter in the ETO with only one squadron operating it for a short time before re-equipment. Likewise the Cobra, one squadron, one mission (?) The RAF liked the Cobra but considered it unsuitable and that 6 months would be needed to sort out all its faults so they gave them to the Soviets who spent six months sorting out all its faults and operated them successfully to the end of the war. The Soviets thought the Tomahawk was the equal of the Bf 109F, the Kittyhawk slightly better. Half the top scoring Russian aces flew the Cobra.

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## Stig1207 (Dec 14, 2018)

Kevin J said:


> The Soviets thought the Tomahawk was the equal of the Bf 109F, the Kittyhawk slightly better. Half the top scoring Russian aces flew the Cobra.



The Finns kicked Soviet butts flying Buffaloes; so I guess we can infer that the USAAF should have trashed all the P-XX and just gone with the F2A. Except that it was a Navy plane, so maybe inter-service rivalry may have got in the way.

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## Shortround6 (Dec 14, 2018)

Schweik said:


> That report is one of many which created the postwar legend of the P-40. The USAAF hated the P-40 as you say almost from the beginning of the war. As soon as they learned that enemy planes flew higher and faster, and even more so once the "Bomber Mafia" achieved ascendancy in the service, and Curtiss Aircraft screwed up again and again, they were no longer in favor and neither was the Hawk family of fighters any more. The legend that the P-40 was a 'dud' was firmly in place by 1943 and was heavily reinforced in the postwar Truman Commission hearings when Curtis Aircraft was being investigated.
> 
> But lets review the history of how this has evolved for a moment.
> 
> ...



I think the actual truth is somewhere between the two extremes.

For example I have never seen any evidence of the part of the trope that says the P-40 was _designed for low altitude and/or ground attack._

There is plenty of circumstantial evidence to the contrary. like the fact that the Army had switched to air cooled engines on all it's purpose built attack planes back in the early 30s and later the A-36 was the only Army plane with an Attack designation to see production (and that was a trick to get around a funding restriction).
Also the fact that armament of the initial P-40 prototype was rather unsuited to ground attack, standard army ground attack planes in the 1930s carried four .30 cal guns for strafing, two synchronized .50 cal guns with just 200rpg (on the prototype) is not very good for strafing. Bomb load is iffy, some sources (most) say none and some say up to six 20lb bombs which is laughable considering the bomb loads of the P-26 Peashooter and the P-35. Army went backwards in it's "ground attack" fighter?
3rd fact. The XP-40 (and all the long nose P-40s) were fitted with the highest altitude engine Allison had in production at the time, over 1000 P-40s being built before the 3rd YP-38 is built so there is no ready to go turbo installation (and early P-38s, B-17s and P-43s had plenty of trouble with the turbo installation).

AS to maneuverability. The P-36 was noted as being very maneuverable with effective and well coordinated controls. There is no reason to believe that changing the engine should change that to any great degree. Increasing the wing loading will affect stall speed and thus turning ability to some extent but roll response, rudder authority (except what may be needed to counteract long nose) and elevator effectiveness should be pretty close. The is plenty of anecdotal evidence to suggest the P-40 was as manuravable as plane of it's size and wing loading could be. There are no reports of ineffective alleirons at speed ( at least not to the extent that some other planes have. ) See http://www.wwiiaircraftperformance.org/naca868-rollchart.jpg
Which shows the P-40F (and there is no reason to believe the other P-40s were much different as there is little or no mention of changes to the Ailerons between models) was among the better rolling aircraft. The chart does have few flaws or lapses like the Spitfire as with the Spitfire to cover ALL models you would need at least 4 curves and not 2. I am guessing that the Spitfire "normal wing" is with the metal ailerons and not the earlier fabric covered ones. 

However "maneuverability" or sluggishness can cover a range of altitudes or conditions, so pilots comments are both subjective and often not well detailed.
The P-40 was actually pretty sleek (as were the P-39 and Allison P-51s) and could go as fast or faster than some other aircraft (SPitfires and 109s ) on the same power while weighing hundreds if not over a thousand pounds more. The problem starts coming in once you are several thousand feet above the critical altitude of the engine (FTH). The American planes are still fast but any maneuver is going to bleed off speed ( it will bleed pretty much the same speed of any opponent doing the same thing.) ANd once speed has bled off it takes the heavier American planes longer to recover the speed, or in some cases due to lower power weight ratios the engine cannot enough extra energy to the plane to keep from losing speed faster than another plane in the same maneuver and winding up slower at the end of the maneuver even if starting at the same or similar speed. 
Rate of climb is a good (but not perfect) indicator of the excess energy available for maneuvering at a given altitude. 
A pilot trying to intercept Japanese bombers at over 20,000ft may complain that his P-40 was sluggish or didn't maneuver well, but what is he really saying? The plane may eventually reach a high level speed but an 8000lb plane with only 700-750hp available may not accelerate like a 6000lb plane with the same amount of power.
the lighter plane may be able to perform a gentile turn (under 2 Gs) without losing speed or altitude that the P-40 cannot follow. Or the lighter plane can turn and climb at the same time and the P-40 can either turn or climb at the same speed but not both.
Now please note the P-40 may be able to trade speed for a high turn rate for limited amount of time and get into a position to fire or break from a plane on his tail but at teh cost of having to either dive to regain speed or fly straight and level while he builds speed up again.

A P-40 at low altitude (lets say under 5000 where it can really use the over boost) may have a power to weight advantage over some other planes or opponents despite the extra weight and may be able to turn with them without losing speed as the engine at 1400-1500hp may be able to replace the energy used up in the turning maneuver. Our low altitude pilot may read the comment of the high altitude pilot and, having never tried to fight at 22-25,000ft in the P-40 may think the high altitude pilot has rocks in his head.

An F4F was slower than a P-40 but once you get several thousand feet above 20,000ft the F4F had more power despite similar weight and higher drag. It's relative performance to the P-40 changed from the lower altitudes.

This was the advantage of P-40F vs the E or the K. Hundreds more HP at 20,000ft and above in a similar weight/drag airplane allowed not only better speed but the ability to maneuver without losing as much speed, It allowed the P-40F to fight at the higher altitudes and stay there vs having to dive away to regain speed/energy.

As to the Bomber mafia this may be another trope. The Army had only ordered 38 B-17s in all of 1939 (when they ordered over 500 P-40s) and only ordered another 42 B-17Ds in early 1940 and ordered the B-17E in Aug of 1940. First B-17E flew in Sept of 1941 which is after the prototype P-40F with Merlin engine (Supplied by the British as Packard was not yet in production).
At this stage of aviation technology (100/100 fuel for one thing) there was no possibility of a single engine fighter being able to escort the B-17 to the reaches of it's range. These early B-17s being rated to carry 4000lbs of bombs over 2400 miles.
Disliking the P-40 because it could not escort the B-17 seems a bit much as nothing the army even had on the drawing boards (let alone in prototype form) could perform the escort mission.
Please remember that in 1940 there was only 1 YP-38 and while it could carry 400 gallons internal for it's two engines (no self sealing tanks) it wasn't planned or plumbed for drop tanks. Therefor no possibility of escorting B-17s even as escorting was understood in 1940.

yes there is plenty of misinformation about the P-40 in print and on the web.

I would say the Army didn't hate the P-40 in the beginning but rather viewed it as an interim fighter to bridge the gap while they developed the planes they really wanted (even if they didn't really know what they were yet) See , P-43--P-44--P47 saga and see P-47A vs P-47B. they were still holding out hope that they could power something with the Continental IV-1430

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## varsity07840 (Dec 14, 2018)

Shortround6 said:


> I think the actual truth is somewhere between the two extremes.
> 
> For example I have never seen any evidence of the part of the trope that says the P-40 was _designed for low altitude and/or ground attack._
> 
> ...



In Bill Bartch's book Doomed At The Start, a 24th PG P-40 pilot described one of the few practice interceptions of B-17s done prior to the war. In essence he said that they were able to make one pass at them and then the B-17s ran away from them. I think it's safe to assume that the P-40s were already at the B-17's altitude, mimicking an interception with adequate early warning. The key word in your comments above is acceleration, especially when the P-40 is operating above 12,000 to 15,000 feet. Higher maximum speed than say, a Ki-43 or A6M is not worth much if it takes all day to get from cruising speed up to combat speed.


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## Schweik (Dec 14, 2018)

I don't disagree with most of that except the part about the influence of the Bomber Mafia.

I do agree that the P-40F / L -- and maybe the lightened N, were the only models that could really fight and maneuver at 20,000 ft which is why that was the variant they used against the Germans in the Med. For the Russians it didn't matter, in the Pacific and CBI they could make hit and run attacks at higher altitudes and safely dive away in single aircraft or pairs or flights of four, because the Japanese didn't have many planes that could catch them in a dive.

I think the USAAF first became aware that the altitude limitations with the Allison Engines were going to be a serious problem during the Battle of Britain and shortly afterward when the English decided to send all their P-40s to the Middle East. This was sharpened in early 1942 when problems intercepting bombers manifested so obviously in the Pacific. The P-40F did improve the situation a lot but not enough to escort high flying bombers, which is why they put so much effort into the turbocharged P-38 and P-43 / P-47 in spite of their long teething problems and development cycles. 

But by the second quarter of 1942 it is quite clear that bomber escort, and specifically high altitude bomber escort was the plan and "Bomber Mafia" were ascendant. Doolittle was part of the Bomber Mafia and even though it was a low-level raid, his propaganda success with the Tokyo raid, along with English problems doing revenge bombing of Germany in daylight, and the billions of dollars spent on the Norden bomb sight were all shifting the focus (and dreams) of USAAF leadership toward what would become the high altitude heavy bomber campaign, and against anything that didn't fit neatly into that plan. This is in part why the decision was made to stop making P-40F/L and their Merlin XX type engines and start heavily ramping up Merlin 60 series Packards.

The early / Allison Engined mustang incidentally was a good example of my point that speed doesn't make the fighter. The P-51A, Mustang I and Mustang II were much faster than any production version P-40, but apparently in part due to problems with the ailerons, they were _not_ particularly good fighters. Much worse than the P-40. They did actually have a need for a high-speed bomber in the A-36, which was in a way the Anglo-American answer to the Fw 190, and it was used fairly heavily in later 1943 and 1944 especially in and around Italy, mainly but problems with dive brakes and high combat losses gradually ended the career of that bomber. The British employed it in their own narrow (but useful) Tac-R and intruder niche with success I think to the end of the war. But it had limited utility.

The Anglo-American hybrid P-51B/C and later D / K etc. series with the Merlin 60 engines turned out to be the real solution to the dreams of the Bomber Mafia, but also fortuitously for the Allies, useful and highly effective in just about every Theater of the War. Better than any P-40 no doubt, which is to be expected as it was a much later innovation. Quite capable of catching and destroying naughty Fw 190s among other things.


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## Schweik (Dec 14, 2018)

varsity07840 said:


> In Bill Bartch's book Doomed At The Start, a 24th PG P-40 pilot described one of the few practice interceptions of B-17s done prior to the war. In essence he said that they were able to make one pass at them and then the B-17s ran away from them. I think it's safe to assume that the P-40s were already at the B-17's altitude, mimicking an interception with adequate early warning. The key word in your comments above is acceleration, especially when the P-40 is operating above 12,000 to 15,000 feet. Higher maximum speed than say, a Ki-43 or A6M is not worth much if it takes all day to get from cruising speed up to combat speed.




It was certainly a major problem, but due to the slow speed and considerably lower operating altitude of the Japanese bombers like the G4M and Ki-21 (compared to a B-17), and the altitude performance limitations of the Ki-43 and the Zero (the A6M2 had a critical altitude of about 18,000') they were able to apparently make multiple passes in flights of four and shoot down considerable numbers of the bombers -even with novice pilots new to the type- and in spite of anemic altitude performance. The dive speed and lower altitude performance of the P-40 helped alleviate the problem - if the escorts chased them down they could turn the tables once they got down about 5,000 feet.

I've posted this article twice to this thread already but it is worth posting again as it's a good analysis of how this was done.

The USAAF 49th Fighter Group over Darwin: a forgotten campaign | The Strategist

However it is worth noting that this kind of tactic wasn't really possible against German or Italian fighters as they were too fast and could also dive well. But in the Med higher altitude level bombing wasn't as common, (most bombing was at lower altitudes) and they eventually had the Merlin P-40s which were fine up to roughly 28,000 feet and also P-38s and Spitfires.


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## Dan Fahey (Dec 14, 2018)

Schweik said:


> I don't disagree with most of that except the part about the influence of the Bomber Mafia.
> 
> I do agree that the P-40F / L -- and maybe the lightened N, were the only models that could really fight and maneuver at 20,000 ft which is why that was the variant they used against the Germans in the Med. For the Russians it didn't matter, in the Pacific and CBI they could make hit and run attacks at higher altitudes and safely dive away in single aircraft or pairs or flights of four, because the Japanese didn't have many planes that could catch them in a dive.
> 
> ...



Problems with the A36 Dive Brakes is a Myth! 
Someone state side made that claim and to wire the Dive Brakes Shut. That was not the issue in use. They pilots had no problems with the Dive Brakes. 

As for high losses....177 were lost to all causes but the amount of damage and havoc they produced was huge. 
Almost all the losses were from AA and ground fire. 
Air to Air they had a nice kill ratio. 

The British loved the P51-A's and very fast at low -medium altitude with the -81 Allison. 
They were more rugged than the Merlin and the Brits fixed up and held on to the few that were produced to the end of WW2.

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## Schweik (Dec 14, 2018)

Dan Fahey said:


> Problems with the A36 Dive Brakes is a Myth!
> Someone state side made that claim and to wire the Dive Brakes Shut. That was not the issue in use. They pilots had no problems with the Dive Brakes.
> 
> As for high losses....177 were lost to all causes but the amount of damage and havoc they produced was huge.
> ...



Mediterranean Air War Vol IV mentions several incidents of A-36 lost to 'wings falling off in a dive' and etc., if you want I can get you the exact dates etc.

I do think they were effective as bombers (and played a useful role) & heavy casualties are normal for Tactical bombers but their retirement seems to have been directly linked to those incidents.


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## Shortround6 (Dec 15, 2018)

Schweik said:


> I don't disagree with most of that except the part about the influence of the Bomber Mafia.



In what way did the "Bomber Mafia" hate the P-40 or work to downplay the P-40s abilities or reputation?

Just curious here as I have not really seen this mentioned.





> I think the USAAF first became aware that the altitude limitations with the Allison Engines were going to be a serious problem during the Battle of Britain and shortly afterward when the English decided to send all their P-40s to the Middle East. This was sharpened in early 1942 when problems intercepting bombers manifested so obviously in the Pacific. The P-40F did improve the situation a lot but not enough to escort high flying bombers, which is why they put so much effort into the turbocharged P-38 and P-43 / P-47 in spite of their long teething problems and development cycles.



The Army was aware (or should have been) of the altitude limitations of the Allison engine in late 1938 and early 1939. It is why the XP-39 was originally built with a turbo, the XP-38 had turbos. At the 1939 fighter trials there were two Seversky fighters, one with a turbo (led to the P-43) and one with a two stage supercharged R-1830, an early model of the engine used in the F4F, there was also a Curtiss Hawk 75 with a two stage supercharger (accounts differ as to mechanical or turbo). The British were making no secret about the FTH of the Merlin III engine and indeed had announced the two speed Merlin X engine including tentative power ratings on 100 octane fuel at the 1938 Paris Air show. During the BoB (Sept 1940) the Army ordered 773 P-47B&C fighters with turbos.
The first flight of the XP-40F (P-40D serial number 40-360)which was fitted with a Merlin engine and first flew on June 30th 1941 which is 8-9 months before the P-40Es were having trouble intercepting Japanese bombers over Darwin. The Problem was shifting from what to do with the 3000 Merlin engines The US got from the first contract with Packard to getting enough Merlins quick enough. When the Packard factory was set up the contract called for 800 engines per month. If two thirds go to the British that leaves 266 engines a month for the Americans. It took Packard until July of 1942 to reach the 800 engine a month production rate (May saw 602 engine built).



> For the Russians it didn't matter, in the Pacific and CBI they could make hit and run attacks at higher altitudes and safely dive away in single aircraft or pairs or flights of four, because the Japanese didn't have many planes that could catch them in a dive.


This is more a failure of Japanese development/production than any great virtue of the P-40 or other allied fighters. The Japanese were slow and late in developing the Ki 61 and while nine Ki 44 were deployed in an experimental unit in Indochina in Dec of 1941 but the Japanese put it on the back burner and then held some of the early production in the Japanese homelands after the Doolittle raid. The P-40 may well have out dived both of these aircraft but the difference in dive capability over the more common Japanese fighters would have been much less marked.
However it points out the fallacy that many aircraft were _designed in response_ to the deployment of an enemy fighter. Given the design/test/tool up cycle of around two years (if you are both lucky and good) the best that could be done was to tweak existing designs. 



> But by the second quarter of 1942 it is quite clear that bomber escort, and specifically high altitude bomber escort was the plan and "Bomber Mafia" were ascendant. Doolittle was part of the Bomber Mafia and even though it was a low-level raid, his propaganda success with the Tokyo raid, along with English problems doing revenge bombing of Germany in daylight, and the billions of dollars spent on the Norden bomb sight were all shifting the focus (and dreams) of USAAF leadership toward what would become the high altitude heavy bomber campaign, and against anything that didn't fit neatly into that plan. This is in part why the decision was made to stop making P-40F/L and their Merlin XX type engines and start heavily ramping up Merlin 60 series Packards.



I believe your timeline is a bit out of whack. Do you have anything to show that in the 2nd quarter of 1942 (April-June) "high altitude bomber escort was the plan" or how the "Bomber Mafia" were ascendant, affected the versions of the P-40 being produceed in the 2nd half of 1942 or the first 1/2 of 1943?
The Fisher P-75 was started in April of 1942 in response to an Army request for proposal issued in Feb 1942 but the initial request proposal, while it wanted long range, was not specifically intended as a escort fighter. That requirement was added until July 1943 when the US Army added six additional prototypes.
If the Army was planning on long range escorts in the 2nd quarter of 1942 they certainly dropped the ball because they didn't come up with workable high altitude drop tanks for well over a year and the Mustang didn't get them for a year and half.
I would also note that Packard didn't stopped making single stage Merlins until Dec 44/Jan 45. In the 24 months of 1943/44 Packard production of single stage merlins was over 800 engines a month for 13 of those months. Peak monthly Packard production (in 1944) was over 2400 engines of both types combined but that required an expansion of the factory over the 800 engine a month size. Packard built almost 27,000 single stage Merlins by the end of 1944 and over 18,500 two stage Merlins.
Now maybe a few hundred more P-40L would have done more for the allies than a few hundred Canadian built Hurricanes.



> They did actually have a need for a high-speed bomber in the A-36, which was in a way the Anglo-American answer to the Fw 190, and it was used fairly heavily in later 1943 and 1944 especially in and around Italy, mainly but problems with dive brakes and high combat losses gradually ended the career of that bomber. The British employed it in their own narrow (but useful) Tac-R and intruder niche with success I think to the end of the war. But it had limited utility.



The A-36 was not intended to be a high speed bomber or Anglo-American answer to the Fw 190. Jabo.
As evidenced by the large dive brakes. dive brakes and high speed low altitude flight don't really go together.
The A-36 was really a funding trick, In the Spring of 1942 the US was finally discovering that the Allison Mustang was a pretty good airplane even as it was. however contracts were winding down and the Army had already spent all of the money allocated to the for fighters. There was money left over (unspent) for attack aircraft however. So a quicky requirement and contract was put out in April of 1942 for the single seat dive bomber, work started in June and the first plane came off the line Oct. It was a way to keep the production line going until the funds for the next fiscal year became available. Once they started putting Merlins in test airframes in Aug of 1942 there was never any intention of ordering more A-36s that I know of. Possible?

Production considerations often affected what was ordered and when and not back room conspiracies.
Allison was constantly expanding their engineering staff but the Army was also requesting all kinds of experiential stuff or diverting effort into the V-2320 24 cylinder engine.
Allison tried using 9.60 supercharger gears like were used in the P-40M&N back in Dec of 1941 but the gears were too narrow and broke under under the strain. to use wider gears called for new casting molds for the crankcase to have a deeper housing for the gears. In the first few months after Pearl Harbor nobody wanted to reduce production of the existing design to change over. Allison was feeling their way in supercharger design as none of the American companies had very good superchargers at the beginning of the war.

*edit *changed KI 43 to Ki 44 in second response. The Ki 44 being sort of a failed opportunity for the Japanese to stay up to Western standards.

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## Schweik (Dec 15, 2018)

Design and military requirements attempted to determine far in advance what was needed - then it was a matter of choosing what kept being produced, what was changed or tweaked, and what was dropped or changed to a different role or given to minor allies or whatever.

The reason for the emphasis on escort fighters started with the over $1 Billion (1940 dollars) spent on the Norden bombsight, a huge project which cost about half as much as the Manhattan project if that helps you understand the scale. The new bombers like the B-17 and B-24, most of the medium bombers and even light bombers like TBF Avengers were already being fitted with the device, 50,000 bombardiers were trained to use it. Huge security measures are implemented to protect the secret machines.

Bombing in Northwest Europe had already long prior 1942 shifting into large scale level bombing. The British had however (mostly) given up on precision daylight bombing and issued the "Area Bombing Directive" in Feb 1942, shifting into using bombers a kind of attrition warfare and to just burn down cities at night since that was about all they could manage. The first thousand bomber raid was sent to Cologne in May of 1942.The Americans and specifically the Bomber Mafia still believed in daylight bombing but it was starting to become clear that daylight bombers would need escorts, despite the faith many still had in the defensive guns of the B-17. To quote the wiki I just linked "_The ACTS _{i.e. bomber mafia]_ officers who believed in the heavy bomber doctrine realized that any other Air Corps expenditures such as for tactical bombers and fighter aircraft would take away from the proposed large fleet of heavy bombers_." Fighters that fit into the plan, potentially, were perceived as more valuable of course. There were B-17 squadrons operating from England from Sept 1942. It took a little while for the Germans to ramp up their activity and it wasn't until mid 1943 that they stopped sending un-escorted raids altogether, but the writing was on the wall from early days, and everybody knew Spitfires didn't have the range.

In the Pacific the issue wasn't so much altitude as range. Existing fighters like the P-40 were too short legged. The P-38 was considered better for long range escorts, with the added benefit of a second engine for those long over-water flights. The P-51 despite it's single engine was ideal when it arrived of course but that came much later. Eventually in the Pacific they got the B-29 which could fly high and fast enough to drop bombs in spite of interceptors.


The Ki-44 was actually used in some numbers and was a little more successful than the shorthand about it tends to suggest, but they just didn't have powerful enough engines yet so it was only competitive rather than dominant. The Ki-61 was a promising design, certainly comparable to the P-40 in many respects and better at altitude, (it was in part intended specifically as P-40 remedy) but the challenges of keeping a license built version of a DB 601 working properly in an open field camp in some place like Rabaul and Wewak, New Guinea were beyond the capabilities of Japanese forward area mechanics. The plane itself was also somewhat complicated to maintain aside from the engines.

I'm not sure even German mechanics could have kept those engines running in a place like this







S


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## Schweik (Dec 15, 2018)

This quote by P-40 double Ace Robert DeHaven explains the context for the P-40 pretty well:

"If you flew wisely, the P-40 was a very capable aircraft. [It] could outturn a P-38, a fact that some pilots didn't realize when they made the transition between the two aircraft. [...] The real problem with it was lack of range. As we pushed the Japanese back, P-40 pilots were slowly left out of the war. So when I moved to P-38s, an excellent aircraft, I did not [believe] that the P-40 was an inferior fighter, but because I knew the P-38 would allow us to reach the enemy. I was a fighter pilot and that was what I was supposed to do. " Source


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## Kevin J (Dec 15, 2018)

Lets look at this another way. The P-40, just under 7000 operated by USAAF, 2250 victories. P-39, about 5000, a few hundred. The P-47, 14000, 3500 v. The P-51, 12000, 5000 v. The P-38, 10000, 3850 v. So the P-40 achieved better results than the P-39 and P-47 and was operated in the most difficult phase of the war. The P-51 achieved the best results but was up against the least well trained opponents. The P-40 did pretty good. Maybe if the Americans had spent the time the Russians did resolving the Cobra's faults and developing suitable air battle tactics before committing it to battle then they would have done just as well. The P-47 was too busy dropping bombs to score lots more aerial victories as it dropped IIRC two/thirds the tonnage of bombs dropped by fighters.

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## DarrenW (Dec 15, 2018)

Schweik said:


> ...So when I moved to P-38s, an excellent aircraft, I did not [believe] that the P-40 was an inferior fighter, but because I knew the P-38 would allow us to reach the enemy. I was a fighter pilot and that was what I was supposed to do. "



This rates as one of my favorite fighter pilot quotes of all time!


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## Schweik (Dec 15, 2018)

Kevin J said:


> Lets look at this another way. The P-40, just under 7000 operated by USAAF, 2250 victories. P-39, about 5000, a few hundred. The P-47, 14000, 3500 v. The P-51, 12000, 5000 v. The P-38, 10000, 3850 v. So the P-40 achieved better results than the P-39 and P-47 and was operated in the most difficult phase of the war. The P-51 achieved the best results but was up against the least well trained opponents. The P-40 did pretty good. Maybe if the Americans had spent the time the Russians did resolving the Cobra's faults and developing suitable air battle tactics before committing it to battle then they would have done just as well.



Good post. Agreed 100%

So that breaks down to a production to claims rate of:

P-39 0.064
P-40 0.321
P-38 0.385
P-47 0.250
P-51 0.416

I think the Soviets were particularly suited for the Airacobra for the following reasons:

The workup you mentioned that we now know they did for several months before deployment, allowing them to familiarize both pilots and planners with the aircraft.
Many Russian pilots were already used to the 'tricky' handling characteristics of planes like the I-16, MiG-3, and LaGG-3, so the P-39 spin characteristics were not as intimidating.
Russians liked heavy guns in the nose.
Most Russian planes were similar - small, low drag, short wings
So much of the combat took place at low altitude, and a short distance from the forward airfields.
P-39 had the heavy gun, good build quality, and good radios unlike most Soviet fighters until fairly late in the war (early-mid 1943 for build quality, late 1943 I think for radios) so this made them similar to Soviet fighters but better in three important ways.

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## varsity07840 (Dec 15, 2018)

Schweik said:


> Design and military requirements attempted to determine far in advance what was needed - then it was a matter of choosing what kept being produced, what was changed or tweaked, and what was dropped or changed to a different role or given to minor allies or whatever.
> 
> The reason for the emphasis on escort fighters started with the over $1 Billion (1940 dollars) spent on the Norden bombsight, a huge project which cost about half as much as the Manhattan project if that helps you understand the scale. The new bombers like the B-17 and B-24, most of the medium bombers and even light bombers like TBF Avengers were already being fitted with the device, 50,000 bombardiers were trained to use it. Huge security measures are implemented to protect the secret machines.
> 
> ...


My understanding is that the Ki-44 came as quite a surprise to the 23rd FG and other 14th AF groups and caused a lot of problems for pilots flying P-40s, regardless of the model they were flying, K, M or N.


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## Schweik (Dec 15, 2018)

varsity07840 said:


> My understanding is that the Ki-44 came as quite a surprise to the 23rd FG and other 14th AF groups and caused a lot of problems for pilots flying P-40s, regardless of the model they were flying, K, M or N.



I think that is correct initially until they realized they could out-turn it. But it was still a problem for 23rd FG etc. (and a similar problem for the Navy in the Philippines) because it meant you had two different strategies that had to be balanced, you couldn't dive from the Ki-44 and you couldn't turn with the Ki-43 or A6M. So if they were operating in a mixed group it could get dicey.


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## michael rauls (Dec 15, 2018)

Kevin J said:


> Lets look at this another way. The P-40, just under 7000 operated by USAAF, 2250 victories. P-39, about 5000, a few hundred. The P-47, 14000, 3500 v. The P-51, 12000, 5000 v. The P-38, 10000, 3850 v. So the P-40 achieved better results than the P-39 and P-47 and was operated in the most difficult phase of the war. The P-51 achieved the best results but was up against the least well trained opponents. The P-40 did pretty good. Maybe if the Americans had spent the time the Russians did resolving the Cobra's faults and developing suitable air battle tactics before committing it to battle then they would have done just as well.


Very interesting information. Never seen that before. The fact that the p38 was only a fraction behind the p51in victories per aircraft produced is not what I would have expected to see.


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## eagledad (Dec 15, 2018)

Gentlemen,

Check this link to get a P-40 pilot's recollection of fighting Me-109s and FW-190s

Flying the P-40 against German fighters, from Capt. James Reed of the 33rd FG

Eagledad

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## Stig1207 (Dec 17, 2018)

michael rauls said:


> Very interesting information. Never seen that before. The fact that the p38 was only a fraction behind the p51in victories per aircraft produced is not what I would have expected to see.



The victories are claims, and the production/ victories is dependant on the accuracy of the claims. The P-51 and P-47 scored the majority of their victories in the ETO in the late war period where the accuracy of claims was much higher; the P-38 only had some 4-500 claims in the ETO. The claiming accuracy was not of the same standard in the other theatres; so the comparison is is not entirely fair.


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## michael rauls (Dec 17, 2018)

Stig1207 said:


> The victories are claims, and the production/ victories is dependant on the accuracy of the claims. The P-51 and P-47 scored the majority of their victories in the ETO in the late war period where the accuracy of claims was much higher; the P-38 only had some 4-500 claims in the ETO. The claiming accuracy was not of the same standard in the other theatres; so the comparison is is not entirely fair.


Interesting. However, my memory is a little fuzzy here so forgive me if im wrong but didn't the 8th air force allow ground kills to be added to totals. I seem to remember iether they were the only air force to do this or alowed it before others not sure which. If so this would seem to more than balance out any confirmation standards by theater.
As far as distribution of gun cameras the majority of p38s had them so I wouldn't think that would be a huge discrepancy.


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## Schweik (Dec 17, 2018)

michael rauls said:


> Interesting. However, my memory is a little fuzzy here so forgive me if I'm wrong but didn't the 8th Air Force allow ground kills to be added to totals. I seem to remember either they were the only air force to do this or allowed it before others not sure which. If so this would seem to more than balance out any confirmation standards by theater.
> As far as distribution of gun cameras the majority of p38s had them so I wouldn't think that would be a huge discrepancy.




Yeah they were using gun cameras on Kittyhawks in the Med from late 1942 so I assume P-38s as well. They were also frequently able to recover crashed enemy aircraft in North Africa, Sicily and Italy to confirm victories.


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## varsity07840 (Dec 17, 2018)

eagledad said:


> Gentlemen,
> 
> Check this link to get a P-40 pilot's recollection of fighting Me-109s and FW-190s
> 
> ...


A long time ago I read a comment by a P-40 pilot who flew in North Africa. I'm not sure what Group he flew with but I'm fairly confident that he was referring to Merlin powered P-40s. In essence he said that try as they might with all kinds of weight savings measures and the like, they couldn't turn a P-40 into a 109.

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## Schweik (Dec 17, 2018)

varsity07840 said:


> A long time ago I read a comment by a P-40 pilot who flew in North Africa. I'm not sure what Group he flew with but I'm fairly confident that he was referring to Merlin powered P-40s. In essence he said that try as they might with all kinds of weight savings measures and the like, they couldn't turn a P-40 into a 109.




That is true and I'm sure a real quote - they never had the same (speed / altitude) performance, but they did have other advantages they could use.

Still I'm sure for fighter pilots they hated giving up the initiative and being attacked from above. Not as big a problem for the Merlin hawks since they were comfortable much higher up - but still a problem.

One thing that did happen though was that as the Bf 109s got faster, especially with the G-6 and later, they also got heavier and less agile. I think the G-6 took more losses than the F-4.


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## Milosh (Dec 17, 2018)

michael rauls said:


> Interesting. However, my memory is a little fuzzy here so forgive me if im wrong but didn't the 8th air force allow ground kills to be added to totals. I seem to remember iether they were the only air force to do this or alowed it before others not sure which. If so this would seem to more than balance out any confirmation standards by theater.
> As far as distribution of gun cameras the majority of p38s had them so I wouldn't think that would be a huge discrepancy.



No, ground kills were not officially counted as kills.


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## Schweik (Dec 17, 2018)

Milosh said:


> No, ground kills were not officially counted as kills.



Really? I thought someone said they did. This thread seems to say it .... ?

USAAF confirmed kills


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## michael rauls (Dec 17, 2018)

Milosh said:


> No, ground kills were not officially counted as kills.


Wow, ive read that so many times from so many sources but who knows maybe your right.


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## Milosh (Dec 17, 2018)

Schweik said:


> That is true and I'm sure a real quote - they never had the same (speed / altitude) performance, but they did have other advantages they could use.
> 
> Still I'm sure for fighter pilots they hated giving up the initiative and being attacked from above. Not as big a problem for the Merlin hawks since they were comfortable much higher up - but still a problem.
> 
> One thing that did happen though was that as the Bf 109s got faster, especially with the G-6 and later, they also got heavier and less agile. I think the G-6 took more losses than the F-4.



Merlin hawks were powered by single stage two speed Merlin 28s.

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## Schweik (Dec 17, 2018)

Milosh said:


> Merlin hawks were powered by single stage two speed Merlin 28s.



Yes and the Merlin hawks had a critical altitude of about 20,000 ft vs about 16,000 for P-40B, 17,000 for P-40M and 12,000 for P-40E or K

See: http://www.wwiiaircraftperformance.org/P-40/Kittyhawk_II_performance_9sept42.jpg

P-40F/L could fight up to about 25-28,000 ft depending on who you ask.


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## Milosh (Dec 17, 2018)

Schweik said:


> Really? I thought someone said they did. This thread seems to say it .... ?
> 
> USAAF confirmed kills



What does Post #11 say?

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## Schweik (Dec 17, 2018)

Milosh said:


> What does Post #11 say?



Gotcha, Ok. Appears I was wrong! Always seemed odd to me anyway...


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## Milosh (Dec 17, 2018)

Schweik said:


> Yes and the Merlin hawks had a critical altitude of about 20,000 ft vs about 16,000 for P-40B, 17,000 for P-40M and 12,000 for P-40E or K
> 
> See: http://www.wwiiaircraftperformance.org/P-40/Kittyhawk_II_performance_9sept42.jpg
> 
> P-40F/L could fight up to about 25-28,000 ft depending on who you ask.



The F/Ls were also much lighter.


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## varsity07840 (Dec 17, 2018)

Schweik said:


> That is true and I'm sure a real quote - they never had the same (speed / altitude) performance, but they did have other advantages they could use.
> 
> Still I'm sure for fighter pilots they hated giving up the initiative and being attacked from above. Not as big a problem for the Merlin hawks since they were comfortable much higher up - but still a problem.
> 
> One thing that did happen though was that as the Bf 109s got faster, especially with the G-6 and later, they also got heavier and less agile. I think the G-6 took more losses than the F-4.



So, here's where I'm at with the P-40, which is my favorite fighter although in fact it was indeed a pursuit plane in the classic pre war nomenclature.
Escort for high altitude bombers? No way. Interceptor? No way UNLESS an inordinate warning time was available, as in China. Offensive fighter sweep fighter in conjunction with top cover. Good. Same for ground attack. Bottom line is that there was no real concept for the P-40 when the real war started.


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## varsity07840 (Dec 17, 2018)

Schweik said:


> Yes and the Merlin hawks had a critical altitude of about 20,000 ft vs about 16,000 for P-40B, 17,000 for P-40M and 12,000 for P-40E or K
> 
> See: http://www.wwiiaircraftperformance.org/P-40/Kittyhawk_II_performance_9sept42.jpg
> 
> P-40F/L could fight up to about 25-28,000 ft depending on who you ask.


No, they could struggle up to that height. fight is a different story.


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## Schweik (Dec 17, 2018)

varsity07840 said:


> So, here's where I'm at with the P-40, which is my favorite fighter although in fact it was indeed a pursuit plane in the classic pre war nomenclature.
> Escort for high altitude bombers? No way. Interceptor? No way UNLESS an inordinate warning time was available, as in China. Offensive fighter sweep fighter in conjunction with top cover. Good. Same for ground attack. Bottom line is that there was no real concept for the P-40 when the real war started.




Just FYI - it's a common myth that P-40s usually operated with top cover in the Med - this is one of the things often brought up to explain lopsided victories by P-40 squadrons against Bf 109s and MC 202s on a few occasions. However most of the time the P-40s had no top cover. 

Up until June 1942 P-40s_ were_ the top cover in the Med, flying escort to medium bombers other (older) P-40s or Hurricanes carrying bombs. There were (almost) no Spitfires in the Theater.

Spits arrived in the Summer of 42 and very gradually ramped-up in numbers, but P-40s were still usually operating without top cover. P-40s had longer range than Spitfires, and the two types typically operated in different areas, while P-38s were usually assigned to escort heavy bombers.

So for example on their famous victories during fighter sweeps over Sardania etc. in 1943, 325th Fighter Group P-40Ls were flying all on their own. That unit, 325th FG was assigned as the escort squadron for a wing of B-26 medium bombers.

Similarly in the Pacific and CBI P-40s were usually the only fighters available and did not have top cover.


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## Schweik (Dec 17, 2018)

varsity07840 said:


> No, they could struggle up to that height. fight is a different story.



20,000 feet was critical altitude meaning that is where performance (specifically speed) _started_ to decline. Service ceiling for the P-40F was 34,400 ft - that is the altitude it could struggle up to.

P-40E's, with a critical altitude 8,000' lower, were able to destroy Japanese bombers over Darwin at 27 - 28,000 feet. P-40E also had a ceiling of 29k', 5k lower than the F.


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## varsity07840 (Dec 17, 2018)

Schweik said:


> Just FYI - it's a common myth that P-40s usually operated with top cover in the Med - this is one of the things often brought up to explain lopsided victories by P-40 squadrons against Bf 109s and MC 202s on a few occasions. However most of the time the P-40s had no top cover.
> 
> Up until June 1942 P-40s_ were_ the top cover in the Med, flying escort to medium bombers other (older) P-40s or Hurricanes carrying bombs. There were (almost) no Spitfires in the Theater.
> 
> ...



In any theater, P-40s were totally vulnerable to being bounced from above, especially in an "interceptor" role. In China, that became real problem when the Japanese turned the tables on the P-40 equipped groups and started using dive and zoom tactics with the Ki-44. There was no theater or environment in which the P-40 was in its element. P-40 pilots always had make do and adapt. It was a stop gap fighter that could be massed produced when we needed it and served relatively well given the circumstances. But, they were kept in production way too long, probably because it was still a viable export aircraft and considered "good enough" in the Pacific and China.

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## Schweik (Dec 17, 2018)

More or less agree, I think it may be more of a glass half-full / half-empty type thing. A matter of how you look at the data. I would characterize it very differently.

Altitude was always an issue but that tends to be very overstated. They developed tactics to deal with it which were very effective. This is part of why it was used for so long - the tactics were worked out pretty early and continued to work.

Not too many Ki -44s ever available, and they (23rd FG etc.) did adapt to them, they only caused problems initially. (P-40 could easily out turn it and dive speed was basically the same)

Still shot down a bunch of 109s and Fw 190s in the Med in 1944 over Anzio so I don't think it was _that _obsolete.


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## michael rauls (Dec 18, 2018)

Milosh said:


> No, ground kills were not officially counted as kills.


You may very well be right about that. Wouldn't be the first time something I've read for years or even decades turned out to be baloney. Was hopping i would have some time this evening to try and research it but worked late so that will have to wait for another day. 
However, even allowing for that any difference in the respective number of p51s to p38s with gun cameras is not going to materially change the victories to planes manufactured ratio. If we suppose that fully one third of p38s had no gun cameras(if gun cameras were showing up in the Med in late 42 its verry doubtful the number was this high but lets go with it).
And then suppose that overclaiming by those early p38s were inflated by 100%( doubled). Lets further asume there is no overclaiming on the part of p51s in those numbers. What you end up with is a 15% reduction in the p38s overall succes rate compaired to the p51. The p38 still has the 2nd best success rate by a wide margin, at least according to the numbers that were posted and is still just marginally behind the Mustang.

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## GrauGeist (Dec 18, 2018)

varsity07840 said:


> In any theater, P-40s were totally vulnerable to being bounced from above, especially in an "interceptor" role. In China, that became real problem when the Japanese turned the tables on the P-40 equipped groups and started using dive and zoom tactics with the Ki-44. There was no theater or environment in which the P-40 was in its element. P-40 pilots always had make do and adapt. It was a stop gap fighter that could be massed produced when we needed it and served relatively well given the circumstances. But, they were kept in production way too long, probably because it was still a viable export aircraft and considered "good enough" in the Pacific and China.


The KI-44 was less maneuverable than the KI-43.
It's only strong point was it's heavier armament and even then, the KI-44 and KI-44-II weren't available in any great numbers until 1943/44

And the P-40 was used to being bounced from above, that was the IJN's favorite tactic - from above and out of the sun. The AVG was well aware of this and their countermeasures were to turn into them and face them head-on. Old-school tactics.

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## Conslaw (Dec 18, 2018)

varsity07840 said:


> In Bill Bartch's book Doomed At The Start, a 24th PG P-40 pilot described one of the few practice interceptions of B-17s done prior to the war. In essence he said that they were able to make one pass at them and then the B-17s ran away from them. I think it's safe to assume that the P-40s were already at the B-17's altitude, mimicking an interception with adequate early warning. The key word in your comments above is acceleration, especially when the P-40 is operating above 12,000 to 15,000 feet. Higher maximum speed than say, a Ki-43 or A6M is not worth much if it takes all day to get from cruising speed up to combat speed.


The Japanese Army's Ki-61 "Tony" fighter seems to have a similar performance envelope to the later P-40, and the Ki-61 hada hard time intercepting the B-29, likely for similar reasons. (Here's a thread that compares the Ki-61 to the P-40L. Kawasaki Ki 61-1 Hien vs Curtiss P-40L Warhawk)


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## Schweik (Dec 18, 2018)

GrauGeist said:


> The KI-44 was less maneuverable than the KI-43.
> It's only strong point was it's heavier armament and even then, the KI-44 and KI-44-II weren't available in any great numbers until 1943/44
> 
> And the P-40 was used to being bounced from above, that was the IJN's favorite tactic - from above and out of the sun. The AVG was well aware of this and their countermeasures were to turn into them and face them head-on. Old-school tactics.



Yes and this is what the British eventually figured out in North Africa, though it took them almost a year. Their original Tactic against Bf 109s was the defensive fighter circle - which worked except when you had guys like Joachim Mariseilles who knew how to attack it, and it was obviously very limited.

In Mid 1942 the Australians apparently initiated a new Tactic of turning the whole squadron into each attack and opening fire with all guns at convergence. They would wait until the last minute and the squadron leader would call on the radio "Prepare to break." and then "Break. Break. Port now." This apparently had a very discouraging effect on attacking Bf 109s and MC 202. Seventy two .50 cal machine guns aimed at you at full auto even for a second or two was somewhat intimidating. If the attacking fighters weren't very disciplined about breaking off their attack and _climbing_ away at high speed, they could then be pursued further.

It seemed to coincide with some kind of mysterious improvement in performance of the P-40s allowing for the higher power. Either due to newer Kittyhawk models or overboosting or both. Australian pilots coming from the Middle East apparently brought this strategy with them to the Pacific.

This quickly spread to all RAF Kittyhawk units. They also began pursuing attacking Bf 109s that did manage to make an attacking pass, which they usually followed by a high speed climbing turn to the right. Later model P-40s apparently had the 'juice' to follow them up into that turn and get a burst or two off. They continued this until the enemy planes either gave up or disengaged, or - if they had to press the issue to get at medium bombers or protect their own airfield for example, continued to engage in which case they would end up in an equivalent E state and the P-40s would start to get the upper hand as the dogfight inevitably descended downward and devolved into individual chases of 2 and 3 aircraft.



The strategy, adopted in the CBI, the Pacific, and North Africa, and also by the Soviets, is apparently a major part of what enabled P-40s to continue being used even where they faced attack from above all the way through 1943 and into 1944. I think it's a major part of he puzzle.

The US fighter groups also began launching attacks against the German air bases. This helped a lot - there was usually a small CAP of 2 or 4 fighters, but most of the enemy planes had to scramble and climb up from below, putting them at a major disadvantage, as medium bombers dropped bombs on their base.

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## varsity07840 (Dec 19, 2018)

GrauGeist said:


> The KI-44 was less maneuverable than the KI-43.
> It's only strong point was it's heavier armament and even then, the KI-44 and KI-44-II weren't available in any great numbers until 1943/44
> 
> And the P-40 was used to being bounced from above, that was the IJN's favorite tactic - from above and out of the sun. The AVG was well aware of this and their countermeasures were to turn into them and face them head-on. Old-school tactics.


The Ki-44 was faster than the P-40 and had a much, much better climb rate.


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## Schweik (Dec 19, 2018)

varsity07840 said:


> The Ki-44 was faster than the P-40 and had a much, much better climb rate.



So was the Bf 109 (in both ways) but P-40s shot down a lot of those.


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## GrauGeist (Dec 19, 2018)

The KI-44 did have a good RoC and it dove fairly well. As for speed, the KI-44 was about even with the P-40.

Also, the Nakajima was lightly armed: Two 12.7mm (cowl) and two 20mm cannon (wing) or four 12.7mm (two cowl, two wing) was not really impressive.
The KI-44 armed with the Ho-301 40mm cannon were useful against B-29s, when the cannon worked...


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## Shortround6 (Dec 19, 2018)

GrauGeist said:


> The KI-44 did have a good RoC and it dove fairly well. As for speed, the KI-44 was about even with the P-40.
> 
> Also, the Nakajima was lightly armed: Two 12.7mm (cowl) and two 20mm cannon (wing) or four 12.7mm (two cowl, two wing) was not really impressive.
> The KI-44 armed with the Ho-301 40mm cannon were useful against B-29s, when the cannon worked...



The 40mm cannon is one of those "what they heck were they smoking" weapons.
Projectile is actually sort of a rocket. 
View attachment 522434

Propellent vented out the 12 holes in the rear and drove the projectile up the rifled barrel.
No ejection to worry about 
However the velocity makes the German MK 108 30mm like like a laser beam, the rate of fire was only 475 rpm(shots a second) and the weapon, as fitted only had 10 round magazines. 
The shell, assuming it hit, was very destructive, but the chances of hit were very, very low.

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## Shortround6 (Dec 19, 2018)

Schweik said:


> So was the Bf 109 (in both ways) but P-40s shot down a lot of those.


Kind of misses the point. 
Modern War is seldom about a specific battle on it's own but rather a series of battles/fights of attrition until one side can dominate the other and inflict it;s will almost whenever and wherever it wants. 

The KI 44, even if not dominate over the P-40, was much closer to the P-40 than the Ki 43 and would negate many of the P-40s advantages or greatly reduce them. 

One of the first (if not the first) 109s the British shot down in WW II was shot down by an Avro Anson, that doesn't mean you shut down Hurricane production and build more Avro Ansons. 
I would guess the Ki 43 wasn't that much more expensive to build than the Ki 43 , certainly not double. but it had double the firepower (even with four 12.7mm guns) was harder to shoot down and was harder for the P-40 to get away from (but certainly not impossible).
A force of Ki 44s compared to an equal force of KI 43s should have had fewer losses in a given time period and inflected greater losses on the Americans, Not saying they would have won, just saying the fight might have been longer and costlier for the Americans.

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## Schweik (Dec 19, 2018)

Actually no it doesn't - the attrition warfare especially in a Theater like the Pacific or CBI is just the aggregate of all of the squadron vs squadron and plane vs plane combats over time. How the former went down affected the latter, albeit with certain factors like say, pilot rescue programs or parachutes having an increasing impact over time.

The Ki-44 was better than the Ki-43 for attrition in one important sense, it had armor and self sealing tanks. So more likely to survive damage without a pilot MiA or KiA. Overall though the Ki-43 probably had a higher victory to sortie rate.

And to be honest, the best Army fighter until the very end of the war and biggest threat to the P-40 was the Ki-61 - when they could keep them running. The Ki-61 could dive at high speeds, climbed well, had good altitude performance, had the armor, self sealing tanks etc., but was also pretty maneuverable. And heavily armed with 2 x 20mm cannon plus 2 x 12.7mm mgs. It made short work of Wildcats and was about even with P-40s (depending on who you believe) It could also hold it's own with F6Fs and tangled with P-38s.

The Ki-44 was really kind of a one trick pony. It could dive (and climb) quite fast but the wing-loading was so high with it's stubby 31' wings (about the same as a Typhoon) that it could basically only do hit and run attacks. I have a model of one of these things in my office it looks like a real short weightlifter. Has a sort of Joe Pesci vibe.

Both aircraft caused some alarm initially but the Ki-61 was harder to adjust to I think. The only real advantage of the Ki-44 over the Ki-61 was it's oversized and heavy but much lower maintenance and less vulnerable Ha-1098 radial engine.

Finally, don't knock the Ki-43 - it was a very reliable and deadly fighter. Just not well suited to attrition war over a long period of time. Maybe I need to do a Ki-43 thread...


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## wuzak (Dec 19, 2018)

I take it that P-40s shot down many Ki-43s?


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## Schweik (Dec 19, 2018)

wuzak said:


> I take it that P-40s shot down many Ki-43s?



Yes they did lol

Supposedly Ki-43s shot down more Allied planes than the Zeros did though, although I don't have any sources for that.


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## GrauGeist (Dec 19, 2018)

Schweik said:


> Maybe I need to do a Ki-43 thread...



There's several out there, but this one was off to a good start and then stopped dead
Ki-43-I or A6M2 as AVG opponent


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## fubar57 (Dec 20, 2018)

There were 64 Ki-43 aces. The highest scoring ace, MSgt. Satoshi Anabuki of the 50th Sentai had 39 kills. Ten others scored over 20

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## Schweik (Dec 20, 2018)

fubar57 said:


> There were 64 Ki-43 aces. The highest scoring ace, MSgt. Satoshi Anabuki of the 50th Sentai had 39 kills. Ten others scored over 20



Pretty good for two machine guns...

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## michael rauls (Dec 20, 2018)

Schweik said:


> Pretty good for two machine guns...


Agreed. I think the Ki43 is one of the really ,really underrated/ ignored aircraft of the war.

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## Milosh (Dec 20, 2018)

8 of his 37 claims were against P-40s.

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## Schweik (Dec 20, 2018)

Like I said - Ki-43 was a tough opponent, especially in the hands of a good pilot... better handling (no high speed lockup) and roll than an A6M for example. I have a model of one of those too, it's an elegant plane. Had some teething issues early on but once worked out it was a very deadly instrument.

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## Greg Boeser (Dec 20, 2018)

Thing is, the armament mentioned for the Ki-43, Ki-44, Ki-61 is for the late war models. Ki-43 I, with just one 12.7 and one 7.7 mg in the nose were front line fighters into mid-'43.
Ki-44s initially had only two 7.7 mgs in the nose and two 12.7s in the wings, and these didn't show up in front line units until mid-'43 (mostly in China). Heavier armed _Shokis_ didn't start showing up until late '43 and '44.
Ki-61 I first deployed to South Pacific armed with same.

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## Schweik (Dec 20, 2018)

Heavier armament for many later war Japanese fighters usually were associated with quixotic attempts to use them as B-29 killers which few of them could manage mainly due to the altitude. They were desperate to save their cities from being incinerated for obvious reasons but could not work it out, must have been unbelievably frustrating.


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## Shortround6 (Dec 20, 2018)

You know, I am still trying to figure out how the Ki 43 shot down so many allied airplanes when there were only 157 of the built in 1941 and 616 built in 1942 and 1347 built in 1943.

And somehow they shot down about 50% of the allied aircraft shot down by fighters during the whole war! ( yeah, I know the war lasted until late summer of 1945).

Just how many aircraft (of all types ) did the allies have in south East Asia in 1941-42?


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## Greg Boeser (Dec 20, 2018)

Apparently, Hurricanes fighting in the CBI were easy meat.

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## Shortround6 (Dec 21, 2018)

Maybe so but how many Hurricanes were there in the CBI, many hundreds or a thousand Shot down?


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## Schweik (Dec 21, 2018)

MSgt. Satoshi Anabuki claimed 21 of them (Hurricanes) shot down, I think that is what he was referring to. They lost a lot of Hurricanes in Singapore and Malaysia etc. in the early weeks of the war, and they continued operating Hurricanes in Burma and India probably longer than they should have, I think maybe right to the end of the war.

A lot of the victims of Ki-43s were also Buffaloes, F4Fs, P-39s, P-40s, and many bombers - hapless Vindicators and Devastators, helpless Blenheims, plus Avengers, Mitchels, Havocs, Helldivers and a few B-24s. And scout / sea planes, flying boats etc. they lost a fair number of them too.

And though outclassed in speed etc., Ki-43s did shoot down some F4Us, F6Fs, P-47s, Mustangs, P-38s etc.

Ki-43 operated in the CBI but also all over the Pacific from the Islands.


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## CORSNING (Dec 21, 2018)

The Ki-44 was really kind of a one trick pony. It could dive (and climb) quite fast but the wing-loading was so high with it's stubby 31' wings (about the same as a Typhoon) that it could basically only do hit and run attacks. I have a model of one of these things in my office it looks like a real short weightlifter. Has a sort of Joe Pesci vibe.
*
Hit and Run was its forte. Its roll rate likened to that of the Fw190 help a lot in this category.*

The only real advantage of the Ki-44 over the Ki-61 was it's oversized and heavy but much lower maintenance and less vulnerable Ha-1098 radial engine.

*Except for its MUCH GREATER climbing ability, rolling ability and acceleration, I'd have to agree
with you.
*

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## Schweik (Dec 21, 2018)

Ah wasn't aware of the good roll rate, that does help!


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## Greyman (Dec 22, 2018)

Schweik said:


> MSgt. Satoshi Anabuki claimed 21 of them (Hurricanes) shot down, I think that is what he was referring to.



According to the work of Christopher Shores, the claims made by Anabuki "seem to be somewhat lacking in veracity", to put it diplomatically.

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## Schweik (Dec 22, 2018)

Greyman said:


> According to the work of Christopher Shores, the claims made by Anabuki "seem to be somewhat lacking in veracity", to put it diplomatically.



Yeah, based on Christopher Shores you can say the same thing about all of the German "experten" and most of the British & American Aces too. Overclaiming by a factor of 2-4 was very common & not neccessarily due to any kind of dishonesty on the part of the pilot.


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## Greyman (Dec 22, 2018)

Anabuki (and to a certain extent the entire 50th Sentai) is a different case in this regard. There are way too many red flags and it seems to be deliberate.


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## Schweik (Dec 22, 2018)

Greyman said:


> Anabuki (and to a certain extent the entire 50th Sentai) is a different case in this regard. There are way too many red flags and it seems to be deliberate.



There are cases like that too


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## varsity07840 (Dec 22, 2018)

Schweik said:


> MSgt. Satoshi Anabuki claimed 21 of them (Hurricanes) shot down, I think that is what he was referring to. They lost a lot of Hurricanes in Singapore and Malaysia etc. in the early weeks of the war, and they continued operating Hurricanes in Burma and India probably longer than they should have, I think maybe right to the end of the war.
> 
> A lot of the victims of Ki-43s were also Buffaloes, F4Fs, P-39s, P-40s, and many bombers - hapless Vindicators and Devastators, helpless Blenheims, plus Avengers, Mitchels, Havocs, Helldivers and a few B-24s. And scout / sea planes, flying boats etc. they lost a fair number of them too.
> 
> ...


Ki-43 pilots never engaged TBD Devastators or SB2U Vindicators.

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## Schweik (Dec 22, 2018)

varsity07840 said:


> Ki-43 pilots never engaged TBD Devastators or SB2U Vindicators.



You sure about that? They were deployed all over- Malaya, East Indies, Philippines, New Guinea, the Solomons, Japanese Home Islands (of course) and etc.


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## varsity07840 (Dec 22, 2018)

Schweik said:


> You sure about that? They were deployed all over- Malaya, East Indies, Philippines, New Guinea, the Solomons, Japanese Home Islands (of course) and etc.


Quite sure. The SB2U only saw combat at Midway. JNAF aircraft only in that fight. Same for TBDs at Midway, Wake, Makin,and Kwajalein.


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## wuzak (Dec 22, 2018)

Schweik said:


> A lot of the victims of Ki-43s were also Buffaloes, F4Fs, P-39s, P-40s, and many bombers - hapless Vindicators and Devastators, helpless Blenheims, plus Avengers, Mitchels, Havocs, Helldivers and a few B-24s. And scout / sea planes, flying boats etc. they lost a fair number of them too.



Ki 43s never shot down Typhoons, therefore Typhoons were better than Hurricanes, F4Fs, P-39s and P-40s....

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## Schweik (Dec 22, 2018)

varsity07840 said:


> Quite sure. The SB2U only saw combat at Midway. JNAF aircraft only in that fight. Same for TBDs at Midway, Wake, Makin,and Kwajalein.



Fair enough!


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## Schweik (Dec 22, 2018)

wuzak said:


> Ki 43s never shot down Typhoons, therefore Typhoons were better than Hurricanes, F4Fs, P-39s and P-40s....



True but if Sgt Anabuki was over Dover with his Ki 43 he would have shot down 21 Typhoons in one mission. Fact.

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## wuzak (Dec 22, 2018)

Schweik said:


> True but if Sgt Anabuki was over Dover with his Ki 43 he would have shot down 21 Typhoons in one mission. Fact.




He would claimed to have shot down 21 Typhoons.....

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## Schweik (Dec 22, 2018)

wuzak said:


> He would claimed to have shot down 21 Typhoons.....



But being a humble man and not wishing to mortify the pride of his enemies, he would obviously understate his actual achievements - since he clearly would have shot down 42 of them and severely damaged another 84.

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## FLYBOYJ (Dec 22, 2018)

Schweik said:


> MSgt. Satoshi Anabuki claimed 21 of them (Hurricanes) shot down, I think that is what he was referring to. They lost a lot of Hurricanes in Singapore and Malaysia etc. in the early weeks of the war, and they continued operating Hurricanes in Burma and India probably longer than they should have, I think maybe right to the end of the war.
> 
> A lot of the victims of Ki-43s were also Buffaloes, F4Fs, P-39s, P-40s, and many bombers - *hapless Vindicators and Devastators*, helpless Blenheims, plus Avengers, Mitchels, Havocs, Helldivers and a few B-24s. And scout / sea planes, flying boats etc. they lost a fair number of them too.
> 
> ...



As mentioned, the Ki-43 never engaged Vindicators and Devastators. They were operated by the JAAF, not the IJN


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## Schweik (Dec 22, 2018)

Yeah I didn't realize how briefly Vindicators and Devastators were employed, I thought maybe some saw combat with IJA fighters at Coral Sea etc.

I would therefore include Dauntlesses on the victim list but they were not so hapless. They were dauntless! lol


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## FLYBOYJ (Dec 22, 2018)

Schweik said:


> Yeah I didn't realize how briefly Vindicators and Devastators were employed, I thought maybe some saw combat with IJA fighters at Coral Sea etc.


You mean IJN? I'd bet dollars to donuts there were no Ki-43s close to the Coral Sea


Schweik said:


> I would therefore include Dauntlesses on the victim list but they were not so hapless. They were dauntless! lol



Ki-43s fought SBDs over Guadalcanal.


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## parsifal (Dec 23, 2018)

varsity07840 said:


> Quite sure. The SB2U only saw combat at Midway. JNAF aircraft only in that fight. Same for TBDs at Midway, Wake, Makin,and Kwajalein.


I think that is correct, though I am unsure if any Dutch vindicators or RNAS were deployed to the CBI or ABDA operational areas. There may also have been a few very similar A-17s deployed with the thai air force


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## GrauGeist (Dec 23, 2018)

There isn't any indication that any Northrup A-17s made it to the CBI (British naming convention: Nomad Mk.I) though the British and Canadians did use them as trainers. The Dutch A-17s remained in the Netherlands and were destroyed by the Luftwaffe during the invasion.


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## Milosh (Dec 23, 2018)

Japanese claims need to be taken with lots of salt.


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## Schweik (Dec 23, 2018)

FLYBOYJ said:


> You mean IJN? I'd bet dollars to donuts there were no Ki-43s close to the Coral Sea



I mean the *I*mperial *J*apanese *A*rmy - and there were Ki-43 units based in New Guinea as I already mentioned though I'm not sure when.



> Ki-43s fought SBDs over Guadalcanal.



Yes, and other places too without a doubt.


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## FLYBOYJ (Dec 23, 2018)

Schweik said:


> I mean the *I*mperial *J*apanese *A*rmy - and there were Ki-43 units based in New Guinea as I already mentioned though I'm not sure when.


Look at a map and see how far New Guinea was from the actual Coral Sea battle ground


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## Greg Boeser (Dec 23, 2018)

Schweik said:


> I mean the *I*mperial *J*apanese *A*rmy - and there were Ki-43 units based in New Guinea as I already mentioned though I'm not sure when.
> 
> 
> 
> Yes, and other places too without a doubt.


First IJA flying units arrived at Rabaul in December 1942. 11th Sentai, flying Ki-43 Is.
These had been picked up second hand from the 64th and 59th Sentais, but were a big step up for the 11th, which had been flying Ki-27s for most of 1942.

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## Kevin J (Dec 23, 2018)

Schweik said:


> I mean the *I*mperial *J*apanese *A*rmy - and there were Ki-43 units based in New Guinea as I already mentioned though I'm not sure when.
> 
> 
> 
> Yes, and other places too without a doubt.


December 1942 well used hand me down Ki-43-I's arrived.


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## Schweik (Dec 23, 2018)

Ok definitely long after Coral Sea so no Vindicators of Devastators in their victim tally. 

I'd guess Ki43 victims included mostly Hurricanes, Blenheims, Buffalos, P-36s, I-15 / 153 and I-16s, then later F4Fs, P-40s, SBDs, Avengers, SB2C, Hudsons, Havocs, Mitchels, Catalinas, OS2Us and various other float and seaplanes, and a few B-24s. No doubt later in the war more than a few of the more modern Hellcats, Corsairs, Seafires, P-38s, P-51s and P-47s though I'm not sure the precise contacts of each types.

I'm tempted to say Fulmar but they only faced Zeros I think in the Indian Ocean. Not sure about any other earlier British bomber types or naval aircraft like the Skua or the Roc, the Swordfish etc. though I think they would have all been dead meat against a Ki43.

I'm sure overclaiming was an issue and probably worse in the Japanese Army than the Navy, most of the Army pilots were NCO's and the Army seemed to be less tightly disciplined than the Navy in many respects. But overclaiming was a major issue all over the world in 1941-1942, and I don't think all those claims were bogus by any stretch. I have no doubt the Ki43 had a deadly bite.


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## Kevin J (Dec 23, 2018)

Schweik said:


> Ok definitely long after Coral Sea so no Vindicators of Devastators in their victim tally.
> 
> I'd guess Ki43 victims included mostly Hurricanes, Blenheims, Buffalos, P-36s, I-15 / 153 and I-16s, then later F4Fs, P-40s, SBDs, Avengers, SB2C, Hudsons, Havocs, Mitchels, Catalinas, OS2Us and various other float and seaplanes, and a few B-24s. No doubt later in the war more than a few of the more modern Hellcats, Corsairs, Seafires, P-38s, P-51s and P-47s though I'm not sure the precise contacts of each types.
> 
> ...


I find it difficult to believe that a fighter armed with one LMG and one HMG scored many victories at all.


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## Schweik (Dec 23, 2018)

Kevin J said:


> I find it difficult to believe that a fighter armed with one LMG and one HMG scored many victories at all.



That is a lack of imagination my friend.

Consider how many kills a Bf 109F2 scored in the Middle East and Russia - certainly hundreds. And all it had was a single 15mm "cannon" and two light machine guns.




it's funny, underestimating the Japanese was one of the major Strategic mistakes of WW2 and it's something we seem to still do in retrospect even knowing what we know.

During the war they went from contempt and derision, to awe, to fear to terror through 1943 and gradually back to contempt again (but still tinged with terror) in 1944 and 45, contributing to the horrific terror bombing campaign the Americans indulged in with their B-29 fire raids.

There is no denying the huge number of Allied airmen, soldiers, and sailors who died fighting the Japanese from 1941-43, and the lesser but still substantial numbers who died in 1944 and 1945.


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## Kevin J (Dec 23, 2018)

Schweik said:


> That is a lack of imagination my friend.
> 
> Consider how many kills a Bf 109F2 scored in the Middle East and Russia - certainly hundreds. And all it had was a single 15mm "cannon" and two light machine guns.
> 
> ...


Tell you something else, I find some of those Bf 109F victories scores a bit dubious too, but the claims are for almost one aerial victory for every K-43 built. I'm not sure the Bf 109 victory claims to aircraft produced was that high.


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## Schweik (Dec 23, 2018)

Everybody overclaimed. But 109Fs were dangerous fighters. So were Ki 43s.

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## Shortround6 (Dec 23, 2018)

Schweik said:


> Consider how many kills a Bf 109F2 scored in the Middle East and Russia - certainly hundreds. And all it had was a single 15mm "cannon" and two light machine guns.



Hmmmmm, one 7.7mm mg firing at 900rpm before you figure in the sychonizer vs two 7.9mm mgs firing at 1100rpm or better before sychronization.
one 12.7mm mg firing 33-35 gram "shells" at no more than 500rpm after sychronization vs a 15mm cannon firing 57 gram HE shells at 700rpm with no sychronization problem. 
not hard to see that the 109F had over double the firepower per second.
German guns had higher velocity so deflection shooting was a bit easier. 

Japanese pilots in the early part of the war were often highly skilled and may have been able to get into a good firing position but there is only so much light firepower can do. 
unless people think the British made a mistake in changing from the eight gun .303 armament which was in fact, much heavier firepower than the one small, one large gun Ki-43s.

proper firepower was a very hard thing to get right and still is. 
Too little and it is hard to convert a firing opportunity into a kill or high damage situation.
Too much firepower carried and you get fewer firing opportunities. 
Obviously what kind of targets you are dealing with also has something to do with it.


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## Schweik (Dec 23, 2018)

More of this 'weight of fire' BS - counter arguments are


The use of one heavy and one light machine gun was only in the first year or so of the war, during which time they were mostly against flimsy and hapless opposition like Blenheims, Buffalos and Hurricanes. Initially there was a problem with the Ho-103 machine guns as you probably know (along with a whole host of other fairly serious teething issues with the Ki-43) but these were fixed and the more normal armament became two 12.7mm machine guns. They did not by the way only shoot HE shells and to imply that is disingenuous, as it is to show the pre-synchronization rate of fire of the German LMGs but the post synchronization rate for the Japanese, _and_ lowball the synchronized ROF.
Like it or not, and I know you and some others here don't, there are a host of fighters in WW2 that were very successful - at least against other fighters- with two or three guns in the nose armament. Ki43 is definitely one of them. Even a Corsair or P-38 pilot had to be very careful against these planes and fight just the right way if they didn't want to die. Hurricanes were dead meat. Yak 1/7/9 series and the Yak 3 were also good examples of this. As was the Bf 109F2 and later F and early G series. And the Macchi 202 as many of them had their wing guns removed by the pilots in the field.
Guns in the nose ARE more accurate than guns out on the wings. Every pilot familiar with both configurations said so. I know you already know this but refuse to believe it anyway because you think your own back of the envelope calculations trump what every war veterans says. But that doesn't change it from being a fact.


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## Schweik (Dec 23, 2018)

Bf 109F2 had light armament by WW2 standards and yet was one of the most deadly fighters that ever flew - FACT.
Ki-43 had fairly light armament by WW2 standards and yet was also one of the most deadly fighters that ever flew - ALSO A FACT.
Yak -1 / 7 / 9 was one of the most successful fighters of the war in spite of also being 'lightly armed' again, FACT.


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## Kevin J (Dec 23, 2018)

Schweik said:


> Bf 109F2 had light armament by WW2 standards and yet was one of the most deadly fighters that ever flew - FACT.
> Ki-43 had fairly light armament by WW2 standards and yet was also one of the most deadly fighters that ever flew - ALSO A FACT.
> Yak -1 / 7 / 9 was one of the most successful fighters of the war in spite of also being 'lightly armed' again, FACT.


The Bf 109F-1/2 had a cannon and two LMG's in the fuselage and was very successful. Its performance outclassed all the fighters by which it was opposed unless you compare it against the Spitfire Vb which arrived at the same time as the Bf 109F-4. Unlike the K-43 it had a cannon. Yes, lots of victories by pilots flying it, it was most successful when operated in dive, shoot and climb to escape mode, but claiming a victory because you and your wing man saw the victim diving and trailing smoke isn't the same as shooting it down. 
The standard armament of the Ki-43-1 was one HMG and one LMG, the armament being increased to two HMG in the Ki-43-II once the HMG problems had been sorted out. Both m/c guns were on the centre line, excellent. It may even be the best fighter available in the first year of the Asia-Pacific war. Do you have the allied figures of losses to compare against?
The Yak was designed as an escort fighter for attack aircraft, its purpose to drive off, shoot down intercepting fighters. Yak's accounted for half the fighters operated by the USSR, but it was the Cobra's and La-5's that produced the top scoring fighter pilots. Do you have the axis figures of losses to compare against? Again, unlike the Ki-43 it had a cannon.
The obsolescent  Hurricane was being produced in greater numbers in 1941 than our wonder plane the Spitfire. Ever asked yourself why?


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## Schweik (Dec 23, 2018)

I'm not so sure that is true that the 109F outperformed all of its opponents. The MiG 3 was faster at altitude (though less maneuverable and had a lousy rate of roll). I believe the Spit V depending on subtype outclimbed it and was faster at some altitudes. The P 38 was certainly 20 or 30 mph faster (but less maneuverable) than the F2 or F4.

The F2 and F in general were considered the best in the series by most German pilots, certainly much better than the faster and more heavily armed G6


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## Schweik (Dec 23, 2018)

As to why they still made so many Hurricanes for so long, I can't think of a logical reason. Great fighter iin 1938, one of the best in the world. Still good in 1940. Declining rapidly in value in 1941 and clearly obsolete by 42. Lot of good pilots died flying them in 42, 43 and 44. Quite a few to Hayabusa.


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## Shortround6 (Dec 23, 2018)

What started this line of posts


Kevin J said:


> I find it difficult to believe that a fighter armed with one LMG and one HMG scored many victories at all.






Schweik said:


> The use of one heavy and one light machine gun was only in the first year or so of the war, during which time they were mostly against flimsy and hapless opposition like Blenheims, Buffalos and Hurricanes. Initially there was a problem with the Ho-103 machine guns as you probably know (along with a whole host of other fairly serious teething issues with the Ki-43) but these were fixed and the more normal armament became two 12.7mm machine guns.



Hey if YOU want to change the goal post fine. But don't call BS when I give the facts on the original position. 




> They did not by the way only shoot HE shells and to imply that is disingenuous, as it is to show the pre-synchronization rate of fire of the German LMGs but the post synchronization rate for the Japanese, _and_ lowball the synchronized ROF.



Well I did put the word shells in quotation marks and I did give a range of weights, the HE projectile weighed 33 grams and the AP weighed 35.4 grams according to one source. 
Now as to over rating the German guns. did I or didn't I??? Wiki says the German MG 17 was good for 1200rpm. Anthony WIlliams in "Flying Guns of WW II ) says 1000rpm (although the MG 15 is rated at 1200rpm) perhaps the 1000rpm is after synchronization? Some sources say the MG 17 was good for 1200rpm when used as a ground gun near the end of the war. 

Japanese 7.7 fixed aircraft machine gun (both army and Navy although they had different type numbers) were developed from the Vickers type E mg and I haven't seen any source that says the type E or any of it's offspring exceed 900rpm unsynchronized. So tell me how I under rated the Japanese 7.7mm machine gun? 

The German MG 151/15 was not synchronized, I also only gave the weight of the HE shell in _this_ comparison The AP projectile weighed 72 grams and will really skew the 'weight of fire'

Mr Williams book (and co author Dr Emmanuel Gustin) says 800-900 rpm for the Japanese 12.7 machine gun in the tables. In the text it says the gun was criticized for it's rate of fire, which was seriously reduced by synchronization. Going back to wiki we have; 

*Rate of fire* 900 RPM 400 RPM (synchronized)

So I rated it almost 25% higher than wiki but that is not good enough for you and you call me disingenuous.

If you can find a decent source that says the gun fired much faster than 500rpm when synchronized please list it. 



> Like it or not, and I know you and some others here don't, there are a host of fighters in WW2 that were very successful - at least against other fighters- with two or three guns in the nose armament. Ki43 is definitely one of them. Even a Corsair or P-38 pilot had to be very careful against these planes and fight just the right way if they didn't want to die. Hurricanes were dead meat. Yak 1/7/9 series and the Yak 3 were also good examples of this. As was the Bf 109F2 and later F and early G series. And the Macchi 202 as many of them had their wing guns removed by the pilots in the field.



No plane was bullet proof and nobody adopted a tatic (on purpose ) of giving the enemy first shot and then turning the tables, so yes it was possible to shoot down aircraft using light armament. However your argument can also be looked at in a different light. The YAK series needed to save all the weight it could for flight performance and a much heavier armament would have seriously degraded flight performance, The Russians sure didn't use light armament because they like to use finesse. And they added guns just as soon as more powerful engines or lighter guns became available. The 109s had a bit of trouble getting the intended engines up to power (both the DB 601E and the DB 605) and there were a number of German pilots who were not happy with light armament. As for the MC 202?? If you are pulling 55kg of guns AND ammo out of plane are you really happy with the fuselage mounted guns or like P-40 pilots who pulled guns out, are you really unhappy with the engine power and flight performance? 



> Guns in the nose ARE more accurate than guns out on the wings. *Every pilot* familiar with both configurations said so.



Really, every pilot? Just how many were familiar with both configurations? 
No British( and Commonwealth) pilots unless they flew Gloster Gladiators or Tomahawks.
For US it was pretty much P-38, P-39 and very early P-40s. for fuselage guns so please come up with some quoted of US pilots that flew them and then flew Warhawks, P-47s or P-51s With something like 200 US pilots flying the long nosed P-40s out of tens of thousands of US fighter pilots during the war that means what? 
Few Russian pilots unless they flew both Russian and Lend lease aircraft. OK I-16 pilots maybe but the i-16 was known to snake and was a lousy gun platform. 
Ah yes, a few German pilots, but how did they know? were they comparing like to like when it came to guns and ammo? 
two slow firing low velocity 20mm MG/FFs vs a faster firing higher velocity fuselage cannon with more ammo than both wing guns put together. Yeah, a really fair comparison. 

And the 109 gun pods aren't quite the same thing as guns in the wing. 

And if you had a mixed battery (some in the fuselage and some in the wings) how did the pilot know which guns scored the hits? 



> I know you already know this but refuse to believe it anyway because you think your own back of the envelope calculations trump *what every war veterans says*. But that doesn't change it from being a fact.



Really???? EVERY war veteran? You talked to them ALL? 

Sorry, it is far from a fact. It is a best an unproven. bu tit is not helped but BS such as this. 

From Defence of the realm
"It’s name may have been “Spitfire” but in the early marks, Supermarine’s legendary fighter was barely an adequate gun platform. It’s _eight .303 machine guns were spaced out across the wing making it difficult to train them to a point ahead of the aircraft _where their collective firepower could inflict heavy enough damage on an enemy aircraft equipped with self sealing fuel tanks. _This was why the Hawker Hurricane, with its eight .303 machine guns coupled closely together, was the superior gun platform in the Battle of Britain_. 

Now for some strange reason the british government say fit to publish diagrams like this






For the Spitfire. Now please note that convergence was later changed to 250yds or so it is claimed. But that must be impossible as that web site said "_it difficult to train them to a point ahead of the aircraft"_

Maybe the harmonization charts were fakes intended to give the pilots confidence? 
Or since you can get all eight guns to hit in a small area in front of the aircraft (although 200-250 yrds ahead that website (and many others) is wrong. 

Now the Hurricane may very well have been a better gun platform but there is more to being a good gun platform than just how close the guns are grouped together. Like steadiness, an absence of snaking or yawing or pitching as the aircraft flies. being sensitive to the controls but not too sensitive so as to have the line of sight to the target disturbed by over corrections or a slightly jittery hand on the stick. 


SO you can call my back of the envelope calculations BS but I have seen an awful lot of BS on the other side of the question.


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## Schweik (Dec 23, 2018)

Plenty of RAF pilots flew one of the 800 or so Tomahawks they had, then later Kittyhawks or other fighters. Plenty of Soviet pilots flew one of the thousands of Lend Lease fighters and later also their own fighters. Golodnikov flew I 16, Hurricane, P 40 P 39 and Yak. Don't throw tantrums because their observations don't match your theories.


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## Schweik (Dec 24, 2018)

Two HMG or a cannon in the nose is better than 8 LMG in the wings


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## Shortround6 (Dec 24, 2018)

Schweik said:


> Plenty of RAF pilots flew one of the 800 or so Tomahawks they had, then later Kittyhawks or other fighters.



SO quote some who say the fuselage guns were better?




> Plenty of Soviet pilots flew one of the thousands of Lend Lease fighters and later also their own fighters.



so quote some who say the fuselage guns were better?



> *Golodnikov* flew I 16, Hurricane, P 40 P 39 and Yak.


One man out of tens of thousands?
And lets see his actual quotes or translations.
Lets also remember that many Russian guns sights were crap and required a different technique to get hits 



> Don't throw tantrums because their observations don't match your theories.



Have I called you out about your behavior or treated you unfairly or insulted you personally?

I think we know who is throwing a tantrum[/QUOTE]


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## Greyman (Dec 24, 2018)

Generally when I read about RAF pilots speak of the wing vs. fuselage armament they expressed a desire for fuselage weapons - and were most envious of the Fw 190's two fuselage machine guns and wing root cannon.



Shortround6 said:


> It’s _eight .303 machine guns were spaced out across the wing making it difficult to train them to a point ahead of the aircraft ... _



I think what they meant to say is that it was difficult to always have the enemy aircraft at the correct range (250 yards) in order to achieve maximum theoretical damage.

Here's a diagram I made based on 'building' the Spitfire's firing cones in a 3D program.





100 yards - 200 yards - 250 yards - 300 yards - 400 yards

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## Schweik (Dec 24, 2018)

It's a really blatantly obvious historical fact gentleman that the P-38 was both faster and much more heavily armed than a BF 109 F4 early G, and yet the latter aircraft is the one that usually came out on top when they clashed. Not always but usually.

P-39 was much faster and much more heavily armed than a Ki 43 but the k43 won three out of four times at least when they clashed.

The hurricane was more heavily armed in terms of weight of bullets for sure had equivalent performance to the ki-43 and yet almost always came out to loser when they clashed.

I don't really care if anybody doesn't understand that Ki43 shot down thousands ot of Allied planes because they certainly did it's a historical fact.

I don't have the loss numbers for all the Allied units conveniently to hand I wish they were more easily available) but I've read enough about all those battles to know what they were generally like and the numbers were pretty grim.

I have recently seen some of the last numbers for the Germans on the Russian front in the early years and they are pretty high in spite of the Soviet losses being even higher.


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## Schweik (Dec 24, 2018)

Shortround6 said:


> SO quote some who say the fuselage guns were better?
> 
> 
> 
> ...



I have some I can transcribe tomorrow


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## Schweik (Dec 24, 2018)

Shortround6 said:


> Have I called you out about your behavior or treated you unfairly or insulted you personally?
> 
> I think we know who is throwing a tantrum



You are right I apologize I was too rude to you, some of the other posts rubbed me the wrong way.


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## Kevin J (Dec 24, 2018)

We seem to have strayed away from the P-39/P-40 topic here a bit. We should leave the P-38 out as it doesn't arrive until after the Bf 109G does. The Bf 109F/Trop has speed, dive, climb, and roll rate going for it and the Ki-43 speed (maybe), climb, roll rate and turning circle against either a Hurricane II/Trop or Spitfire V/Trop. So I do know which planes I won't be choosing for a dogfight.  Hurricane for rear area air defence, no problem, rugged plane, good destructive armament, should be able to take on a Me 110 without a problem and competitive with the Bf 109E below 15000 feet, not so sure about the Ki-45 though. The Spitfire V should do better against a Ki-43, but I've not seen any figures. The Spitfire Vc Trop struggled against the A6M3 below 20000 feet. It would be nice to see a breakdown of exactly what types the Bf 109F and Ki-43 were victorious over. Can I assume that the Ki-61 got deployed rapidly to the Pacific because of the inadequacy of the Ki-43's armament against heavier American bombers such as the Mitchell, Flying Fortress and Liberator? Was the Ki-43 successful in the CBI because it was mainly up against planes like the Hurricane, Blenheim, Vengeance and Wellingtons (?) although less successful against the Warhawk(?). The Mitchell packed a heavy defensive punch for a twin and could be used as a long range bomber, is that why the IJA needed Ki-44's in China to defeat Mitchells and Liberators. In the case of the Hurricane, 6500 were built in the UK between 1942 to 1944, so assuming 1500 went to the Soviets, 1500 to the Middle East, that would leave 3500 for the K-43 to shoot down.


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## Shortround6 (Dec 24, 2018)

We have a tremendous amount of variables here as some of these aircraft had variations even among what are supposed to be the same model. 
Assuming much of anything with the Japanese may be hard as they had problems with production all during the war which affected not just new models of engines and air frames but guns and ammo. It took quite a while to get the Ho 103 sorted out apparently. So saying they should have mounted four of them in the Ki 43 and Ki 61 from the start may have been better in theory but not practical given the amount of guns and 12.7mm ammo being produced. HE shells are almost always much harder to produce than ball or AP rounds due to the fuses needed. Japanese did develop a "fuseless" round but that depended on a small quantity of air being heated as the nose crushed and a more sensitive than normal explosive filling.
That lead to more accidents. 

I am not sure the Hurricane should be getting quite the blame that it is because at some point well before the end of production they gave up any pretense of it being a fighter and it was used pretty much in the ground attack role

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## Schweik (Dec 24, 2018)

Kevin J said:


> We seem to have strayed away from the P-39/P-40 topic here a bit. We should leave the P-38 out as it doesn't arrive until after the Bf 109G does. The Bf 109F/Trop has speed, dive, climb, and roll rate going for it and the Ki-43 speed (maybe), climb, roll rate and turning circle against either a Hurricane II/Trop or Spitfire V/Trop. So I do know which planes I won't be choosing for a dogfight.



Spit V/Trop should be much faster than a Ki-43 at most altitudes, Hurricane II as well I would think though it would be closer.

What is the armament of a 109G-2 or G-4? Similar to 109F4 right?



> Hurricane for rear area air defence, no problem, rugged plane, good destructive armament, should be able to take on a Me 110 without a problem and competitive with the Bf 109E below 15000 feet, not so sure about the Ki-45 though. The Spitfire V should do better against a Ki-43, but I've not seen any figures. The Spitfire Vc Trop struggled against the A6M3 below 20000 feet.


Yes but I think mainly because they hadn't adopted new tactics for it (still using Western desert tactics basically) and had a ton of maintenance problems, plus range issue.



> It would be nice to see a breakdown of exactly what types the Bf 109F and Ki-43 were victorious over.



I would love to see that as well.



> Can I assume that the Ki-61 got deployed rapidly to the Pacific because of the inadequacy of the Ki-43's armament against heavier American bombers such as the Mitchell, Flying Fortress and Liberator? Was the Ki-43 successful in the CBI because it was mainly up against planes like the Hurricane, Blenheim, Vengeance and Wellingtons (?) although less successful against the Warhawk(?). The Mitchell packed a heavy defensive punch for a twin and could be used as a long range bomber, is that why the IJA needed Ki-44's in China to defeat Mitchells and Liberators. In the case of the Hurricane, 6500 were built in the UK between 1942 to 1944, so assuming 1500 went to the Soviets, 1500 to the Middle East, that would leave 3500 for the K-43 to shoot down.



You have a good point about the bombers. My theory about the twin nose guns (or 1 cannon + 2 LMG) is that it's perfectly good for fighter vs. fighter, and it's good enough for attacking lightly defended bombers, especially since HMG and cannon pretty much outrange defensive LMGs. This is also why I think the 8 LMG armament was limited, .30 cal (.303, 7.9mm etc.) lose a lot of their 'punch' at longer range.

But as bombers start to acquire more 20mm, 13mm, 12.7mm etc. defensive guns the simple two nose gun armament is no longer sufficient. The early B-25 had a lot of heavy guns though it was still somewhat weak on defense as it lacked proper tail guns. However they seemed to have survived pretty well in combat in the Med. A-20 was a bit more vulnerable but also very good compared to say, a Blenheim. B-24 had tons of guns but also seemed to be weak for some reason (they shot down a lot of them in the Med that is for sure and they seem to have lost some to Ki-43s as well).

By the way I was just reading in Shores MAW Vol II, a British pilot commented that they took out a pair of LMGs from their Spit VC(2)s to improve climb and altitude performance. And I also previously read they took out two of the cannon from Hurri IICs if they were expected to face fighters. So that was not just an adaptation for P-40s by any means.

On the contrary though, when they expected to shoot down a lot of bombers or have to strafe AAA they wanted as many guns as possible. They routinely switched out P-40s from 4 to 6 guns and back again depending on what kind of missions they were flying.



One question I have for you who know the British kit well. I'm struck simultaneously by what a deathtrap the Blenheim and Beaufort seemed to be while on the other hand, the Beaufighter seemed to be excellent. Isn't it almost the same plane?



EDIT: Sorry about the broken quote tags, that drives me nuts. Fixed.

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## Kevin J (Dec 24, 2018)

Schweik said:


> Spit V/Trop should be much faster than a Ki-43 at most altitudes, Hurricane II as well I would think though it would be closer.
> 
> What is the armament of a 109G-2 or G-4? Similar to 109F4 right?
> 
> ...



You have a good point about the bombers. My theory about the twin nose guns (or 1 cannon + 2 LMG) is that it's perfectly good for fighter vs. fighter, and it's good enough for attacking lightly defended bombers, especially since HMG and cannon pretty much outrange defensive LMGs. This is also why I think the 8 LMG armament was limited, .30 cal (.303, 7.9mm etc.) lose a lot of their 'punch' at longer range.

But as bombers start to acquire more 20mm, 13mm, 12.7mm etc. defensive guns the simple two nose gun armament is no longer sufficient. The early B-25 had a lot of heavy guns though it was still somewhat weak on defense as it lacked proper tail guns. However they seemed to have survived pretty well in combat in the Med. A-20 was a bit more vulnerable but also very good compared to say, a Blenheim. B-24 had tons of guns but also seemed to be weak for some reason (they shot down a lot of them in the Med that is for sure and they seem to have lost some to Ki-43s as well).

By the way I was just reading in Shores MAW Vol II, a British pilot commented that they took out a pair of LMGs from their Spit VC(2)s to improve climb and altitude performance. And I also previously read they took out two of the cannon from Hurri IICs if they were expected to face fighters. So that was not just an adaptation for P-40s by any means.

On the contrary though, when they expected to shoot down a lot of bombers or have to strafe AAA they wanted as many guns as possible. They routinely switched out P-40s from 4 to 6 guns and back again depending on what kind of missions they were flying.



One question I have for you who know the British kit well. I'm struck simultaneously by what a deathtrap the Blenheim and Beaufort seemed to be while on the other hand, the Beaufighter seemed to be excellent. Isn't it almost the same plane?[/QUOTE]
I agree the Blenheim was a deathtrap, but it may surprise you to know that Beauforts in RAAF service actually scored aerial victories. As for the Beaufighter, if one of them hit you with its four 20 mm cannon and 6 lmg then I think you're a gonna. The Blenheim and Beaufort should be fast enough to evade the Cr 42, G50, A5M, Ki-27 and IJN float planes at max speed.


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## Shortround6 (Dec 24, 2018)

Kevin J said:


> You have a good point about the bombers. My theory about the twin nose guns (or 1 cannon + 2 LMG) is that it's perfectly good for fighter vs. fighter, and it's good enough for attacking lightly defended bombers, especially since HMG and cannon pretty much outrange defensive LMGs. This is also why I think the 8 LMG armament was limited, .30 cal (.303, 7.9mm etc.) lose a lot of their 'punch' at longer range.



this is common view (the outrange lighter guns bit) but one that may not have much basis in facts.
Or at least it depends on the guns involved.

You have the light guns which almost universally used rather streamlined bullets. 
Then you had the Italian and Japanese 12.7mm and the German 13mm guns which used rather short stumpy poorly shaped bullets. Yes they were heavier per unit of frontal area than the rifle caliber bullets but they slowed down at about the same rate and had similar times of flight out to any practical air combat range.
Then you had the US .50 and the Russian 12.7mm which used heavier bullets of very streamlined shape and they had higher muzzle velocities. Aside from the German 15mm they had the longest practical range of aircraft guns until you get to the big German 30mm. 

For the 20mm guns we are all over the place as projectile weights and velocities vary considerably and nobody was using a projectile with great streamlining, although some were better than others. 
The 20mm Hispano was pretty much a match for the US .50 unless you have a bar bet going. Every other 20mm was worse. Some were a lot worse and show no practical range advantage over some of the rifle caliber machine guns.


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## Schweik (Dec 24, 2018)

One of the things I have come to understand about the .30 cal guns is that their energy dissipated at range, as in after ~ 300 meters or maybe quite a bit less, the energy for punching through armor or ripping open self sealing fuel tanks etc. had declined a lot. You or somebody commented upthread or in the P-40 vs Typhoon thread about how even HMG bullets got deflected by hitting wing spars and so on and didn't always get through armor, well this is much more true for LMGs.

20mm cannon of course will explode regardless of range pretty much and do their ripping apart stuff thing, and .50 cal will still punch through engines, put big holes in fuel tanks and rip apart defensive gunners from 1,000 meters or more.


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## Schweik (Dec 24, 2018)

Kevin J said:


> I agree the Blenheim was a deathtrap, but it may surprise you to know that Beauforts in RAAF service actually scored aerial victories. As for the Beaufighter, if one of them hit you with its four 20 mm cannon and 6 lmg then I think you're a gonna. The Blenheim and Beaufort should be fast enough to evade the Cr 42, G50, A5M, Ki-27 and IJN float planes at max speed.



Doesn't really surprise me, but the Beaufighter seemed to perform much better. Sometimes they lost a lot of them and it did seem somewhat vulnerable to Bf 109s or MC 202s but it could handle basically anything else and usually dominate. One of the few planes which seemed to have the number of the Ju 88 for example.

I can see Beauforts shooting down a crap plane but what you see in the operational history is, 
12 Blenheims go out, 9 get shot down, no damage to target
12 Beauforts go out, 6 get shot down, one enemy ship damaged by a torpedo (maybe sunk)
12 Beaufighters go out, 3 get shot down, 6 enemy planes shot down, 4 E-boats sunk and a Submarine strafed to death

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## Schweik (Dec 24, 2018)

Shortround6 said:


> I am not sure the Hurricane should be getting quite the blame that it is because at some point well before the end of production they gave up any pretense of it being a fighter and it was used pretty much in the ground attack role



Not really blaming Hurricanes so much as just think they were too vulnerable even as fighter bombers by 1942, let alone 1943 or later. Carrying bombs slowed them down a lot.

Same for P-40s really - while very helpful as fighter bombers almost everywhere in 1942 I don't think they were that great at ground attack, at least for Europe (Italy), in 1943 or certainly by 1944. Carrying a bomb, let alone 1500 lbs of them, slowed it down too much making it vulnerable to both flak and fighters. Could still fight after releasing the bombs but it was a stop gap solution for ground attack.

Of course, CAS was a dangerous game regardless and I'm not sure what they had which could fit the niche. A-36 had potential but not quite up to the task, P-38s, P-47s and Corsairs were pressed into the role, as were Typhoons, but I'm not sure they were ideally suited either. P-51 and Spit definitely weren't.

Mosquito of course, and perhaps the A-26 Invader seemed to be one of the few successful marriages of damage causing ability with speed and agility but maybe too expensive to make for that dangerous role. Plus Mossie had inline engines.

I think for CAS or precision bombing by 1943 you needed either a very fast twin engine plane (350 mph or better) or a very fast dive bomber (300 mph or better at least... which means probably an internal bomb bay) which the Americans or British really didn't have as such. The Helldiver was supposed to do this job and almost had the chops but had extended and very painful teething problems it's not clear to me if they ever resolved. I think it was a bad design. The fighter bombers were pressed into service as shallow angle (45-60 degree) dive bombers but at great cost in terms of losses to flak and fighters.

Strafers like the A-20 and B-25 with all the guns in the nose worked in the Pacific but not as viable against German light AAA.

The Japanese had some promising designs which would fit this bill except no self sealing tanks usually (Yokosuka D4Y) and / or couldn't get them into the War anywhere near quick enough. (B7N)

The B7A looked fantastic on paper - 350 mph, more maneuverable than a Zero supposedly, 2 x 20mm cannon, 1,800 mile range and could dive bomb or also carry a torpedo. Not sure about armor or self sealing tanks. But they couldn't get the thing running, development cycle was an amazing 4 years (1941-45). And meant for giant carriers that never had a chance to fight, though they could have made it a great land based bomber.


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## Shortround6 (Dec 24, 2018)

Schweik said:


> 20mm cannon of course will explode regardless of range pretty much and do their ripping apart stuff thing, and .50 cal will still punch through engines, put big holes in fuel tanks and rip apart defensive gunners from 1,000 meters or more.



The .50 can do that *if it hits! *
In ground combat this much easier to do than in air to air combat. Most of time in ground combat the gun is stationary and the target not moving very fast, OK a truck can be moving 30 meters a second or more but that is about it. You can also see misses sometimes and correct the fire. 

In the air every range is a guess. Some pilots didn't use tracers or many of them. Even a slow bomber is moving 100 meters a second and a fast one is going 140m/s. Time of flight to 1000 meters could be nearly 2 seconds . It varied with altitude further complicating things. Tracers are going to tell you where you should have been aiming 2 seconds ago, assuming that a, your tracers last 1000 meters and b, you can actually see your tracers at that distance. But in the air there are no puffs of dust, dirt from near misses. Talk of 1000 meter shots air to air was just that 99% of time, talk.

I would note that rifle caliber bullets are quite capable of killing people or holding radiators/ oil coolers at 1000 meters.


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## wuzak (Dec 24, 2018)

Schweik said:


> By the way I was just reading in Shores MAW Vol II, a British pilot commented that they took out a pair of LMGs from their Spit VC(2)s to improve climb and altitude performance. And I also previously read they took out two of the cannon from Hurri IICs if they were expected to face fighters. So that was not just an adaptation for P-40s by any means.



Taking out 2 lmgs didn't change the firepower of the V as much as taking out 2 of the P-40's hmgs (which amounted to 1/3 of the firepower).

Some Spitfire Vs had their cannon removed, so they could reach the high altitude Ju 86P reconnaissance aircraft.


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## Schweik (Dec 24, 2018)

wuzak said:


> Taking out 2 lmgs didn't change the firepower of the V as much as taking out 2 of the P-40's hmgs (which amounted to 1/3 of the firepower).
> 
> Some Spitfire Vs had their cannon removed, so they could reach the high altitude Ju 86P reconnaissance aircraft.



Yeah I was reading about that. They put in two .50 cals. Good for a long chase.


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## wuzak (Dec 24, 2018)

Schweik said:


> Yeah I was reading about that. They put in two .50 cals. Good for a long chase.



No, they did not.

They had the 4 x 0.303" lmgs.


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## Schweik (Dec 24, 2018)

wuzak said:


> No, they did not.
> 
> They had the 4 x 0.303" lmgs.



That is not what Shores said. I can go look for the quote it's in Vol II


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## fubar57 (Dec 24, 2018)

The “e” wing which carried the 20mm cannon and .5 mgs appeared in the second half of 1944


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## Schweik (Dec 24, 2018)

I was referring specifically to field modifications made to intercept high flying Ju 86 recon planes in 1942. I think we both were. I'll try to find the quote.


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## Milosh (Dec 24, 2018)

Ju86 over Blighty, The JU86P

The Ju86 was also over Egypt and intercepted.

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## Schweik (Dec 25, 2018)

Here is the passage from Shores (MAW II, pages 232-233). The bolded emphasis is by me. Other than that it's a direct transcription from Shores and you ware welcome!

"During the spring and summer of 1942, Junkers JU-86-R-1 reconnaissance aircraft (referred to in British records as the Ju 86P) were supplied in small numbers to 2.(F)/123 based on Crete, supplementing that unit's Ju 88D's. This aircraft flew several ultra-high photographic missions over British military installations in Egypt. This advanced aircraft was powered by two Jumo 207 diesel engines with two-stage superchargers, and had a pressurized cabin for it's two-man crew.

Throughout June 80 and 1 SAAF Squadrons had been attempting to intercept these high-flying reconnaissance intruders which were appearing regularly over Port Said and the Delta area. Each squadron had stripped a HUrricane IIb of it's armor and eight of the 12 machine guns in order to achieve sufficient performance to catch one of these pressurised aircraft. However, to date these attempts had met with no success. With 8th Army dug in along it's 'last ditch' line at El Alamein, and with Rommel preparing a major offensive to penetrate that line, the ability of the Ju86Rs to run line coverage of large parts of the British defenses and rear areas at regular intervals, effectively unchallenged, was not acceptable.

In an initial bid to counter this menance, half a dozen Spitfire VI high-altitude fighters had arrived in Egfypt. With it's pressurised cockpit, however, this variant was just too heavy to reach the altitude at which the Ju 86R were operating. Engineers at 103 Maintenance Unit at Aboukir then sought to lighten two Spitfire Vs in a similar manner to that employed with the Hurricanes. All unneccessary equipment was removed, including armor and the four .303in machine guns. The engines were modified to gfive an increased compression of 7:1, although this decreased take-off boost, and each fighter was fitted with a four-bladed propeller taken from a Spitfire VI; all protruding nuts were also cut off flush wherever possible. At least three Spitfires, BP985, BR114 and BR234 were modified this way. *They were also fitted with locally-manufactured pointed wingtips and an armament of two .50 in Browning machine guns instead of the 20mm cannon.*"

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## Schweik (Dec 25, 2018)

By the way, as far as the P-39 goes, in the Med per Shores (volume IV) the 350th Fighter Group started having a lot more success toward the middle of 1943. Anyone interested in the P39 might want to take a closer look at that unit. Maybe the pilots figured out how to use the plane properly like the Russians did.

Apparently they shifted from 'coastal patrol' to a more active role largely inside Italy in Summer of 1943

350th Fighter Group - Wikipedia


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## michael rauls (Dec 25, 2018)

Guess this is off topic but I hope everyone is having a great Christmas!!!

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## Schweik (Dec 25, 2018)

Merry Christmas (and etc.)!


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## CORSNING (Dec 25, 2018)

Merry Christmas All.

Happy Birthday Jesus.

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## Dimlee (Dec 27, 2018)

Schweik said:


> Russia - particularly in the key battles at Moscow and Leningrad



I'd suggest to exclude Battle of Moscow from this list. There were some P-40s but too little too late and serviceability was low (not the aircraft's fault). On the other hand, Murmansk should be mentioned.


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## Schweik (Dec 27, 2018)

Dimlee said:


> I'd suggest to exclude Battle of Moscow from this list. There were some P-40s but too little too late and serviceability was low (not the aircraft's fault). On the other hand, Murmansk should be mentioned.



I'm going to guess you know better than I.

By the way, what do you think of this analysis of why the P-39 did well in Soviet hands. Or do you think it really did?


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## Dimlee (Dec 27, 2018)

Schweik said:


> I'm going to guess you know better than I.
> 
> By the way, what do you think of this analysis of why the P-39 did well in Soviet hands. Or do you think it really did?



I think it was good analysis.
SHOULD the P39 have been able to handle the Zero? Was it training or performance?


One thing just came to my mind... That "twitchy" I-16 - in the line of argument (Soviet pilots were accustomed to "twitchy" aircraft). Modern pilots who flew restored I-16s did not always agree with that characteristic. Vladimir Barsuk (designer, manager and test pilot) considered I-16 to be easy flown and stable aircraft.


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## Kevin J (Dec 27, 2018)

P-400. Can I assume that the reason the RAF specified more armour than the P-39D was that its intended use was to attack invasion barges and other small warships like MTB's? In that case, the best use of the P-400 was at Guadalcanal.
Eastern Front. If its true that there was always lots of cloud cover then the low altitude rating of the Allison would not have put either the Cobra or Kittyhawk at a disadvantage, and would certainly have hindered the Luftwaffe tactics of dive down, attack and zoom back up. The Cobra then becomes the better fighter unless its Naval Aviation and its range you want.
Conversely, any variant of the Cobra would have been seriously at risk in North Africa throughout the year, and Italy in the Summer.
As a bomb truck the Kittyhawk is better.
For Coastal Patrol in the Med, the Cobra's low altitude performance and speed would have been useful plus the ability to carry oversized drop tanks.
As an mid altitude escort and air superiority fighter the Merlin powered Warhawk is clearly superior in performance and range. The difference in max speed wouldn't matter.
The Allison powered Kittyhawk with its bigger wing and longer range would be a better bet than the Cobra in the Pacific for Interception, Air Superiority and Escort enabling it to get higher than a similarly powered Cobra.
To me it looks like the Cobra is a niche product.
Perhaps the best use of the Cobra in the USAAF would have been rear areas air defence and certainly not on the front line as at Port Moresby, although maybe the P-400 could have been useful for opposing Japanese landings in New Guinea. Maybe even deploying the P-39D at Hawaii to free up more Warhawks for use in the Western Pacific.


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## Schweik (Dec 27, 2018)

I would think with good long range drop tanks P-39 might have been useful as a low altitude escort for General Kenneys A-20 and B-25 strafers and Beaufighters. Probably very good for taking out torpedo bombers too.

One of the things that struck me from that 325th Fighter Group documentary was the long (5 months / 130 hours) training period they got on type, on the P-40, plus another 2-3 months in Theater doing 'light duty', low risk convoy escort and so on before the crap really hit the proverbial fan. They also had the benefit of flying with and getting training from highly experienced RAF veterans who knew the P-40 very well.

This is kind of similar to the careful 4 month workup the Soviets gave the P-39, also I think supervised by combat veterans (although new to the type). 

I don't think American or Aussie units in the South Pacific had that kind of luxury with any of their planes. Not sure about the Med but it would be interesting to look at training times, especially time allocated for 'training on type' for P-39. I don't think they had much and they also had nobody in the Theater to learn from. Maybe should have imported a few Russians via Iran or something...


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## Schweik (Dec 27, 2018)

Dimlee said:


> I think it was good analysis.
> SHOULD the P39 have been able to handle the Zero? Was it training or performance?
> 
> 
> One thing just came to my mind... That "twitchy" I-16 - in the line of argument (Soviet pilots were accustomed to "twitchy" aircraft). Modern pilots who flew restored I-16s did not always agree with that characteristic. Vladimir Barsuk (designer, manager and test pilot) considered I-16 to be easy flown and stable aircraft.



er my bad sorry I forgot we already discussed it...

As for I-16 traits, I think it was just one of those fighters you had to get used to. Like a Fw 190.


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## Shortround6 (Dec 27, 2018)

Schweik said:


> I would think with *good long range drop tanks* P-39 might have been useful as a low altitude escort for General Kenneys A-20 and B-25 strafers and Beaufighters. Probably very good for taking out torpedo bombers too.



The problem is NOT getting to the fight, it is *GETTING HOME *after the fight. Once you drop the tank you have the internal fuel to fight (at a high rate of consumption) and get home on and getting home means sometimes looking for the home field in low clouds or rain squall that weren't there when you left. 
An Allison could burn just under 3 gallons a minute using that extra boost so beloved by P-39 and P-40 fans and about 2.3 gallons a minute at military power. You could go through 46-48 gallons in 5 minutes of WEP and 10 minutes of military power. or over 1/3 of your internal fuel in a 120 gallon P-39. Granted once the fight is over you can drop down to around 0.75 gallon a minute or less but you better hope you didn't further away from base than you can get back to. Sticking drop tanks for combat use (getting to the fight, not actually fighting with) that are bigger than the internal tanks can be a recipe for disaster. Ferry tanks are a different story.

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## BiffF15 (Dec 27, 2018)

Shortround6 said:


> The problem is NOT getting to the fight, it is *GETTING HOME *after the fight. Once you drop the tank you have the internal fuel to fight (at a high rate of consumption) and get home on and getting home means sometimes looking for the home field in low clouds or rain squall that weren't there when you left.
> An Allison could burn just under 3 gallons a minute using that extra boost so beloved by P-39 and P-40 fans and about 2.3 gallons a minute at military power. You could go through 46-48 gallons in 5 minutes of WEP and 10 minutes of military power. or over 1/3 of your internal fuel in a 120 gallon P-39. Granted once the fight is over you can drop down to around 0.75 gallon a minute or less but you better hope you didn't further away from base than you can get back to. Sticking drop tanks for combat use (getting to the fight, not actually fighting with) that are bigger than the internal tanks can be a recipe for disaster. Ferry tanks are a different story.



SR6,
Something to consider or to piggyback on what you mentioned regarding the fuel burn once the fight is over. Did they go right to max fuel conservation profile post fight or did they egress the immediate battle area at MIL power for a few minutes to lessen the chance of being bounced? Speed lowers the odds of a successful bounce but shortens the time aloft, and or range.
Cheers,
Biff

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## Shortround6 (Dec 27, 2018)

Dimlee said:


> One thing just came to my mind... That "twitchy" I-16 - in the line of argument (Soviet pilots were accustomed to "twitchy" aircraft). Modern pilots who flew restored I-16s did not always agree with that characteristic. Vladimir Barsuk (designer, manager and test pilot) considered I-16 to be easy flown and stable aircraft.



Well, one book on Russian aircraft says that pilots converting to the Mig-3 from I-16 had less trouble than pilots converting from biplanes, in part because whatever quirks the Mig-3 had were at least similar to the ones the I-16 had. 
Lets not forget that Russian build quality was, shall we say, not the best. An I-16 that was assembled correctly (proper CG location and all that stuff) and rigged properly may be quite different than than one operating on the ragged limit of proper CG location with controls that are misaligned. I would venture to guess that any I-16 operating today is much better built/aligned and in spec than well over 90% of the wartime I-16s.

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## Shortround6 (Dec 27, 2018)

BiffF15 said:


> SR6,
> Something to consider or to piggyback on what you mentioned regarding the fuel burn once the fight is over. Did they go right to max fuel conservation profile post fight or did they egress the immediate battle area at MIL power for a few minutes to lessen the chance of being bounced? Speed lowers the odds of a successful bounce but shortens the time aloft, and or range.
> Cheers,
> Biff


I think that that was one of the big differences between flying/fighting in Europe and flying/fighting in the Pacific (or perhaps CBI?) Over occupied Europe they very often kept the speed high all the way back to the coast even if not a military or max continuous settings. Once they were over water it was a judgement call as to when to start slowing down/conserving fuel. 
In the Pacific once you were 50 miles or so from the enemy base or target it may have been common practice to slow down to 200mph or so for the rest of the trip back. 
Some navy data sheets actually figure operational radius that way, and cruise to and from the target is in single digits for thousands of feet. 

No AA guns in the middle of the ocean to dodge.

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## Kevin J (Dec 28, 2018)

Schweik said:


> I would think with good long range drop tanks P-39 might have been useful as a low altitude escort for General Kenneys A-20 and B-25 strafers and Beaufighters. Probably very good for taking out torpedo bombers too.
> 
> One of the things that struck me from that 325th Fighter Group documentary was the long (5 months / 130 hours) training period they got on type, on the P-40, plus another 2-3 months in Theater doing 'light duty', low risk convoy escort and so on before the crap really hit the proverbial fan. They also had the benefit of flying with and getting training from highly experienced RAF veterans who knew the P-40 very well.
> 
> ...



The Australians relegated their P-39D's to rear area air defence and recce duties so I guess they figured out that their usefulness was limited in the South Western Pacific, but then they had the benefit of hindsight.


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## Kevin J (Dec 28, 2018)

Shortround6 said:


> Well, one book on Russian aircraft says that pilots converting to the Mig-3 from I-16 had less trouble than pilots converting from biplanes, in part because whatever quirks the Mig-3 had were at least similar to the ones the I-16 had.
> Lets not forget that Russian build quality was, shall we say, not the best. An I-16 that was assembled correctly (proper CG location and all that stuff) and rigged properly may be quite different than than one operating on the ragged limit of proper CG location with controls that are misaligned. I would venture to guess that any I-16 operating today is much better built/aligned and in spec than well over 90% of the wartime I-16s.


If you look at the wings of the I-16 and Mig-3, I think you'll find them remarkably similar in shape and that the Mig-1 is actually an evolution of the I-16.


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## wuzak (Dec 28, 2018)

Kevin J said:


> P-400. Can I assume that the reason the RAF specified more armour than the P-39D was that its intended use was to attack invasion barges and other small warships like MTB's? In that case, the best use of the P-400 was at Guadalcanal.



Or it could have simply been that the RAF regarded the P-39D as having insufficient armour.


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## Kevin J (Dec 28, 2018)

wuzak said:


> Or it could have simply been that the RAF regarded the P-39D as having insufficient armour.


Don't know the answer to that. All I know is that they only used it for beating up trawlers and barges. I really can't think of any use for the plane other than as an anti-invasion ground attack fighter. It simply never had the altitude performance required for use by the RAF for anything other than ground attack. Once the threat of invasion is over with the Russians stalling the Germans in the East, it really is of no further use to them, whichever way you look at it.


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## Shortround6 (Dec 28, 2018)

A lot of fighters squadrons were "trained" by beating up trawlers and barges on their first few missions into enemy airspace. It gave a small taste of combat while limiting the exposure to enemy counter measures.
Fly across the channel, find something floating in the water (not even a train on dry land), shoot it up and scoot for home before any German fighters show up (hopefully). 
This was still being done in late 1943 with US P-47 and P-51 squadrons. A few fighter sweeps over coast of Belgium or Holland or France before starting escort missions, and the first few escort missions would be short ones, not into Germany as a combat debut. Bomber units followed a similar path. Bomb a coastal target in France first, then inland targets then deeper raids.

The British used one squadron of P-39s for about a couple of weeks before giving up, they never got out of the training stage. The squadron may have had the P-39 for it longer but it takes time to change to a new plane, they had stopped flying operations.

I don't think we can draw an conclusions as to how the British planned to use the P-39 from that very limited combat use.

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## Greyman (Dec 28, 2018)

There was a brief thought towards anti-tank work but the poor performance of the M4 sealed off that particular avenue.


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## Shortround6 (Dec 28, 2018)

British Aircobras had 20mm Hispanos unless we are talking about a later batch? Possibly lend lease?


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## Greyman (Dec 28, 2018)

Had the M4 turned out to be effective this would have been a later batch.


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## Schweik (Dec 28, 2018)

Apparently they had some success with P-39s as strafers / ground attackers in Italy

350th Fighter Group - Wikipedia


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## Dimlee (Jan 5, 2019)

Kevin J said:


> If you look at the wings of the I-16 and Mig-3, I think you'll find them remarkably similar in shape and that the Mig-1 is actually an evolution of the I-16.



This is interesting theory. Mkoyan's team was de-jure part of Polikarpov's organisation, indeed. But in my opinion, young designers tried to "revolutionise" existing fighter's designs, not to continue to develop them further.


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## CORSNING (Jan 5, 2019)

Kevin J said:


> If you look at the wings of the I-16 and Mig-3, I think you'll find them remarkably similar in shape and that the Mig-1 is actually an evolution of the I-16.



Kevin,
I always thought many of the Russian planes had similar designed wings 
until I took a much closer look at them in the last several years. The Mig-3's
wing was much different than the very straight wing of the I-16. However if
you continue on the Polikarpov lineage, the Mig-3's wing compares more
closely to the I-185's slightly bent wing.

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## Dimlee (Jan 5, 2019)

CORSNING said:


> However if
> you continue on the Polikarpov lineage, the Mig-3's wing compares more
> closely to the I-185's slightly bent wing



MiG-1 was based on Project 61 (a.k.a. project/fighter "K") initially developed by Polikarpov's team and later given to newly formed department of Mikoyan/Gurevich - along with over 80 of staff. So the route of this lineage is known.

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## CORSNING (Jan 5, 2019)

OK then, back on topic. I have not had the time to do the fine tuned
comparison of these two from start to finish like I did with the P-51 vs.
F4U. But I did manage to put together a comparison of the height of their
WW2 performance versions. For just a little fun, I added the similar engine
P-51A. The first set of figures are for P-39N No. 42-4400. Figures in
[parenthesis] are for P-40N-1 No. 42-9987 (P-40K with same drag conditions
as P-40N). Third figures are for P-51A No. 43-6007.

*P-39N-1* @ 7,301 lb. .[* P-40N-1* @ 7,413 lb. ]. *P-51A* @ 8,000 lb.

Altitude / Speed / Climb
Meters / MPH / FPM
S.L........344 / 3980 .[ 332 / 3520 ]. 376 / 3500
1,000..362 / 4145 .[ 345 / 3600 ]. 387 / 3625
2,000..381 / 4220 .[ 360 / 3680 ]. 400 / 3750
3,000..398 / 3940 .[ 375 / 3465 ]. 412 / 3405
4,000..394 / 3460 .[ 375 / 2965 ]. 413 / 2925
5,000..388 / 3060 .[ 373 / 2480 ]. 410 / 2455
6,000..382 / 2985 .[ 367 / 2025 ]. 405 / 2025
7,000..376 / 2230 .[ 362 / 1635 ]. 399 / 1605
8,000..367 / 1745 .[ 356 / 1265 ]. 389 / 1160
9,000..356 / 1310 .[ 348 / -.940 ]. 367 / -.765

Full Throttle Height: 398.5 mph./2,957 m. .[ 378 mph./3,215 m. ]. .415 mph./3,170 m.
Critical Altitude: 4360 fpm./2,225 m. .[ 3720 fpm./2,438 m. ]. .3785 fpm./2,255 m.

Turn Time 360 degrees: 19 seconds. .[ 16.6 seconds. ]. .21 seconds.

Maximum roll rate: 75 deg./sec./235 mph. .[ 95 deg./sec./270 mph. ]. .86 deg./sec./400 mph.

Combat Ceiling (1,000 fpm. climb): 31,820 ft. .[ 28,920 ft. ]. .27,650 ft.
Service Ceiling (100 fpm. climb): 38,500 ft. .[ 38,200 ft. ]. .35,100 ft.

Range (clean): 360 ml. .[ 650 m. ]. .1,000 ml.

Maximum War Emergency Power: 1,420 hp. .[ 1,480 hp. ]. .1,480 hp.

Wing loading (at take-off): 34.15 .[ 31. 41 ]. .34.33 lb. / sq. in.

Power loading (take-off weight at maximum engine power): 5.122 .[ 5.009 ]. .5.405 lb./hp.

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## CORSNING (Jan 5, 2019)

Dimlee said:


> MiG-1 was based on Project 61 (a.k.a. project/fighter "K") initially developed by Polikarpov's team and later given to newly formed department of Mikoyan/Gurevich - along with over 80 of staff. So the route of this lineage is known.



*Dimlee,
You are absolutely right sir. Thank you for the added information.*

*From 'Soviet Combat Aircraft' page 65 (with a little help):*

*" M. Gurevich and V. Romodi, who had great experience and vast academic qualifications,
became deputies of (Artyom) Mikoyan. The OKO staff comprised engineers and designers
from the Polikarpov Design Bureau, and though this was not ethical with respect to Nikolay
Policarpov, he made light of the situation upon his return from Germany. During his absence
his project (I-200) had been slightly altered. The length of the fuselage was increased to
improve longitudinal stability, wing centre section fuel tanks were installed in addition to
the fuselage fuel tanks, and the airframe became a mixed structure instead of all-metal.
Nevertheless, it was still undoubtedly Polikarpov's aerodynamic configuration."*

*" Polikarpov was more concerned about the division of his design bureau into two parts.
With one half he at once began work on another project, the I-185 fighter. Although the
design and mock-up construction of the I-185 proceeded faster than the I-200 project.
The OKO team had a great advantage owing to the powerful industrial base of Plant 1."*

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## CORSNING (Jan 5, 2019)

The P-39 had the quickest climb rate of the three in my post #405 right up to its 
maximum ceiling. The P-51 was the speed king right up to its maximum ceiling.
The P-40 was without a doubt the most maneuverable.

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## Schweik (Jan 5, 2019)

Where did you get your turn times from?


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## Schweik (Jan 5, 2019)

CORSNING said:


> OK then, back on topic. I have not had the time to do the fine tuned
> comparison of these two from start to finish like I did with the P-51 vs.
> F4U. But I did manage to put together a comparison of the height of their
> WW2 performance versions. For just a little fun, I added the similar engine
> ...



The P-51A had some kind of problem with the ailerons which was fixed on the P-51B/C and later. I think later versions had a very good roll rate.

This is interesting though I think it would make more sense to compare P-40K or L to the others as they were contemporaries. P-40N wasn't used that much in combat (by the RAF as a bomber in Italy, by the RAAF a bit in the Pacific and by the USAAF in Burma and India.

By contrast the P-40K was widely used from Russia to Tunisia to the Solomon Islands and China, and the L, along with the F, were the main variants used by the USAAF against the Germans. 

But it is harder to find those numbers.

If you are going to use P-40N note that at 57" / WEP the climb are a little lower initially but hold up better to a little bit higher altitude

http://www.wwiiaircraftperformance.org/P-40/A29-412-climb-WEP.jpg

it starts from 3100 fpm and peaks at 3380 at 6800 ft.

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## CORSNING (Jan 6, 2019)

it starts from 3100 fpm and peaks at 3380 at 6800 ft.[/QUOTE]

*These figures are for an R.A.A.F. P-40N-1 loaded to 7,900 lb. I used load figures
of all three aircraft in their "interceptor" mode.*

*The turn time for the P-39N are from Russian figures.*

*The turn time for the P-40N-1 came from calculations from Henning Ruch. I do
not like using calculated figures if I can help it. However, I have found that Mr. Ruch 
has been very accurate in his calculations to date. The P-40C weighing 7,475 lb.
(USSR figures) was capable of 18.0 seconds. The P-40N-1 was a much higher
powered improved version weighing 7,413 lb.*

*The turn time for the P-51A is much harder to come by. Russian figure for the 
Mustang I is 23 seconds. In Erik Pilawskii's Fighter Aircraft Performance of WW2
he states the P-51B turn time at 4,000 m./ 21 seconds. The turn time I gave
for the P-51A at 1,000 meters is an educated estimation.*

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## Shortround6 (Jan 6, 2019)

Schweik said:


> This is interesting though I think it would make more sense to compare P-40K or L to the others as they were contemporaries. P-40N wasn't used that much in combat (by the RAF as a bomber in Italy, by the RAAF a bit in the Pacific and by the USAAF in Burma and India.
> 
> By contrast the P-40K was widely used from Russia to Tunisia to the Solomon Islands and China, and the L, along with the F, were the main variants used by the USAAF against the Germans.



There were about 1300 P-40Ks built, There were over 5000 "N"s built, granted many Ns never left the US and the last few hundred went straight to storage/scrap. 

The Ns were lightest short nosed P-40s built (the aluminium radiators, oil coolers, magnesium wheels and things done) and so should perform the best. The N-1 should be the ultimate Allison P-40 as it also had only 4 guns, 201-235 rpg (?), the forward fuel tank taken out. The electric starter was not installed, a smaller battery and a few other bits left out (like all blind flying instruments). 

What is somewhat puzzling is that slightly later versions of the P-40 (like N-5s) were over 20mph slower than the prototyped N-1 (converted K) at similar powers. 

Some units did get their older P-40s replaced by P-40N only to have P-51s and P-47s replace them in a few months. Probably in an effort to cut down on the amount of types the logistics chain had to support. 

Interestingly the The US Armies inventory of P-40s peaked in April of 1944 at 2499 planes, I believe that includes the ones used as trainers in the US (?)


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## michael rauls (Jan 6, 2019)

Shortround6 said:


> There were about 1300 P-40Ks built, There were over 5000 "N"s built, granted many Ns never left the US and the last few hundred went straight to storage/scrap.
> 
> The Ns were lightest short nosed P-40s built (the aluminium radiators, oil coolers, magnesium wheels and things done) and so should perform the best. The N-1 should be the ultimate Allison P-40 as it also had only 4 guns, 201-235 rpg (?), the forward fuel tank taken out. The electric starter was not installed, a smaller battery and a few other bits left out (like all blind flying instruments).
> 
> ...


I've read ( I believe on Wikipedia so take with a grain of salt) that the reason some of the later production blocks of p40Ns were slower was that they were fitted with additional armor for the ground attack role.


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## Shortround6 (Jan 6, 2019)

Armor, if internal, doesn't have much effect on speed. If fitted outside where it might disrupt airflow then things may be different.

Effect on climb is much different,

A Spitfire IX lost about 22mph at low altitudes by adding a 500lb and an unfaired rack.

Blaming a few hundred pounds of armor (which should have much less drag than a 500lb bomb) for a 20mph or so speed loss seems a bit out out line.

One estimate for the P-51 said that an extra 1000lb INTERNAL was good for 3mph speed loss. That may have been optimisc.

Many accounts of aircraft blame weight increases for loss of speed while taking no account of the increase in drag of some bits and pieces, going back to the Spitfire, the early external BP glass windscreen was figured to be worth 6mph. Weight was not all that much, a few dozen pounds?

Adding and subtracting guns in the wings (protruding gun barrels) can change the airflow pattern (and lift) slightly in the area of the gun bay/s. the ejection slots cause drag. 

differences in weights are much easier to come by that changes in drag.

Later P-40s got the full 6 gun armament, they got bigger under wing racks, the electric starters and bigger batteries went back in (in fact many of the light P-40N-1s had the starters changed, bigger batteries put in, the front tank replaced in the field, some even got two .50 cal guns added)

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## Schweik (Jan 6, 2019)

The later model P-40Ns were much heavier but also were flown at lower power ratings. Rated HP was down from ~1300 something to ~1200 hp. I think that is the main reason for the speed difference.

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## Shortround6 (Jan 6, 2019)

ALL P-40Ns got the 9.60 gear engines, the -81,-99 and -115 engines all had the same power ratings. 

The 9.60 supercharger gear engines made less power down low and more power at "higher" altitudes, Higher starting at under 10,000ft. 

Which engine is going to give more speed in a P-40 depends on what altitude you are flying. 

The Engine in K was rated at 1325hp for take-off which has little or no bearing on speed in the air, The engine in the N was rated at 1200hp for take off,

However the engine in the K was only good for 1150hp at 12,000ft (no ram) while the "lower powered: engine in the N was good for 1150hp at 15,500ft (also no ram) 
as a rough guide you are going to loose about 2.5% of power per 1000ft of altitude as you go up from 10,000ft and a little bit more per 1000ft if you start from 15,000ft (most engines drop to zero HP at about 55,000ft, they can't make enough power to exceed internal friction without a rather extraordinary supercharger set up) 

The engines in the N could make over 1400hp at around 10,000ft using WEP while the engine in the K with it;s slower turning supercharger impeller was close to running out of breath. Perhaps 5-6% more power than the 1150hp at 12,000ft. Perhaps a bit more due to RAM?


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## Schweik (Jan 6, 2019)

Well it may just be how they reported the tests, but all the books I have say the early "interceptor" version of the P-40N-1 through N-15 I think, had a V-1710-81 rated for 1,360 hp (WEP) while later ones N-20 through N-35 had the V-1710-99 which were rated only at 1,200 hp. Then the last batch, P-40 N-35 (only ~ 250 made) had the V-1710-115 which again was rated at ~1,300 hp.

That could just be a matter of recommended throttle settings I don't know.

There is a table in "The Curtiss Hawks" on P 231 which gives the following max HP values:

V-1710-39 (P-40E) was rated at 1470 hp @ 56" Hg for WEP
V-1710-73 was rated 1550 hp at 60" Hg for WEP
V-1710-81 through 115 all say they are rated at 1360 hp @ 57" Hg for WEP but they show a lower "normal rated" power of 955 vs. 1,000 for the -39 or -73

So it's possible the lower speed shown for the later model P-40Ns (usually around 348 mph vs. 378) may just be because they rated the speed at military power instead of WEP. This kind of thing is done a lot in aviation books.

As Shortround noted weight seems to have less effect on speed than drag does, though it does eventually also have an effect and the later model P-40Ns were much more heavily loaded than the N-1. I could go either way on the reason.

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## Shortround6 (Jan 6, 2019)

Schweik said:


> V-1710-39 (P-40E) was rated at 1470 hp @ 56" Hg for WEP
> V-1710-73 was rated 1550 hp at 60" Hg for WEP
> V-1710-81 through 115 all say they are rated at 1360 hp @ 57" Hg for WEP but they show a lower "normal rated" power of 955 vs. 1,000 for the -39 or -73




HP ratings without altitudes are almost useless. 

I am not blaming you Schweik, or trying to say that you are in anyway trying to shade the argument. All to many books, magazine articles and websites overlook this "little detail"
either through ignorance or if they are trying to push an agenda of their own. ANd then these figures are copied over to other articles and become part of those tropes you object to. 

Try plotting some of these power ratings on graph. 

The -39 was good for 1490hp at 56in at 4300ft, It was good for 1150hp at 11,700ft.
The -73 was good for 1580hp at 60in at 2500ft, it was good for 1150hp at 12,000ft. 
Both use the 8.80 supercharger gear. 
Forget the pressure for now, just plot the power vs altitude and then run the lines down to sea level and up as far as you care to go, they should hit zero on the mid 50,000ft range. You can get arguments as to exact figure. 

Now do the same for the -81 and up engines, 1410hp at 9,500ft and 1150hp at 15,500ft.
This later engine was rated at 1360hp at sea level but that is because the throttle is part closed at sea level (so were the 8.80 engines, just not as much) and the resulting losses and extra heat created by the faster spinning impeller pushed the engine/fuel combination closer to the detonation limit. As the plane climbed the throttle could be opened more and more. 

Then add in 1-3,000 ft worth of altitude depending on RAM (forward speed)

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## Schweik (Jan 6, 2019)

Not debating it but where do you get 1410 hp @ 9,500 ft for the -81? And where do you get the altitudes for WEP ratings for the -39 and -73? My books just say 'Sea Level' for WEP. I'm always looking for new and more accurate sources.

Aside from the critical altitude ratings for HP which I agree with you should be standardized and consistent, they also more generally just need to standardize whether they are showing cruise, military, takeoff or WEP power for a given aircraft. They should probably show all of the above.

Wasn't 60" approved for later model P-40E / V-1710-39 as well as for the -73?

I gather P-40K was mainly good for high speed quite low but that did have it's uses.

The -81 series engines were reportedly good up to about ~17,000 ft which is much higher than the other P-40s, the P-40E and K basically had performance ceilings of about 12,000' which is actually worse than the Tomahawk (V-1710-33) which was rated useful up to 15,000'.

The F and L / Merlin XX ones were good up to 20,000 and apparently still combat worthy at around 25,000' which is a big difference and a major improvement

Is it true what some people are saying that Merlin XX had weak power down low?

S


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## CORSNING (Jan 6, 2019)

This is interesting though I think it would make more sense to compare P-40K or L to the others as _they were contemporaries_. P-40N wasn't used that much in combat (by the RAF as a bomber in Italy, by the RAAF a bit in the Pacific and by the USAAF in Burma and India.

The first P-40 N-1s were delivered in March 1943. The first P-39Ns were delivered in November
1942. The first P-51As were delivered in March 1943. I would say using the P-40N-1 would be
a contemporary comparison. The first long fuselage P-40Ks (-10) were delivered in October
1944.


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## Schweik (Jan 6, 2019)

Delivered in 43 maybe, but I'm not sure when that means they were in action... and I'm not certain about P-39 variants but I can tell you for 100% certain that P-40F, L and K and A-36 (P-51) were all flying in combat together, (with some kinds of P-39s though I don't know what variant) quite a bit in Italy and the Med in 1943 and early 1944.

I know that P-51A and P-40K were also in combat together in Burma but P-40N may have been as well. That would be later in 43 or into 44.

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## Shortround6 (Jan 6, 2019)

Schweik said:


> Not debating it but where do you get 1410 hp @ 9,500 ft for the -81? And where do you get the altitudes for WEP ratings for the -39 and -73? My books just say 'Sea Level' for WEP. I'm always looking for new and more accurate sources.



I am getting most of the information from "Vees for Victory" by Danial Whitney. A history of the Allison engine


Schweik said:


> Wasn't 60" approved for later model P-40E / V-1710-39 as well as for the -73?



This one is subject to question, approved by who? sometimes the engine company and the Military did not agree. Sometimes the the engine company wanted to use higher ratings and sometimes the engine company didn't really want to approve WEP ratings ( Try and find WEP ratings in P & W company literature for example).
As far as the -39 goes, remember that the change to the nitrided crankshaft came part way through the production run, they did not change the model number of the engine. 
Any -39 engine could make the level of power at 60in of MAP, the question was for how long? or how many times. 



Schweik said:


> Is it true what some people are saying that Merlin XX had weak power down low?



That really depends on when. As in 1940 when first issued and the boost was limited to 9lbs (48in) or when it was cleared to use 12lbs boost or when it went to 14lbs in low gear and 16lbs in high gear. 14lbs is 58in (or close) and the Merlin XX (in British service) was rated at 1485hp at 6000ft no RAM, it may not have been cleared for 1600hp or so at sea level but 1485hp at 6000ft doesn't look too shabby to me.

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## Schweik (Jan 6, 2019)

Agreed, obviously talking about 1942 here


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## CORSNING (Jan 6, 2019)

April 1943 90 P-39Ns are supplied to the French in North Africa. June 1943
the 18th FG becomes operational with P-39Ns at Guadalcanal.

1 September 1943 P-40N-5s become operational at Baker Island.
I'm still working on the P-40N-1.

September 1943 the P-51A becomes operational with the 23 rd. FG.

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## Schweik (Jan 6, 2019)

CORSNING said:


> April 1943 90 P-39Ns are supplied to the French in North Africa. June 1943
> the 18th FG becomes operational with P-39Ns at Guadalcanal.
> 
> 1 September 1943 P-40N-5s become operational at Baker Island.
> ...



Okay fair enough consider me schooled


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## tomo pauk (Jan 6, 2019)

Schweik said:


> Not debating it but where do you get 1410 hp @ 9,500 ft for the -81? And where do you get the altitudes for WEP ratings for the -39 and -73? My books just say 'Sea Level' for WEP. I'm always looking for new and more accurate sources.
> ...
> Is it true what some people are saying that Merlin XX had weak power down low?



Don't believe those people - factory approved 1300 HP+ by late 1940, 1470 HP by late 1942: link1 link2

As for the V-1710-81:

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## Wildcat (Jan 7, 2019)

CORSNING said:


> The first long fuselage P-40Ks (-10) were delivered in October
> 1944.


Hi Corsning. I have 77 sqn RAAF operational with P-40K-10's on 22 February 1943 out of Gurney airstrip, New Guinea.

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## varsity07840 (Jan 7, 2019)

Schweik said:


> The P-51A had some kind of problem with the ailerons which was fixed on the P-51B/C and later. I think later versions had a very good roll rate.
> 
> This is interesting though I think it would make more sense to compare P-40K or L to the others as they were contemporaries. P-40N wasn't used that much in combat (by the RAF as a bomber in Italy, by the RAAF a bit in the Pacific and by the USAAF in Burma and India.
> 
> ...


The P-40N was widely used by the 5th AF in the Pacific and still equipped the 110th TRS during the invasion of the Philippines in Nov. 1944

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## Schweik (Jan 7, 2019)

Interesting, but were they in combat much? Were they still racking up victories in 1944? My understanding for the Pacific (as distinct from the CBI) was that most US P-40 units were kind of out of the game except for CAP (patrol over airfields etc.) because they longer had the range to reach Japanese targets. I know Australian Kittyhawk units were still getting some victories through 1944, I believe New Zealanders had already switched to Corsairs in 1943 (though they were no longer encountering many enemy planes anyway and I don't think made any victory claims with them).


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## CORSNING (Jan 7, 2019)

Wildcat said:


> Hi Corsning. I have 77 sqn RAAF operational with P-40K-10's on 22 February 1943 out of Gurney airstrip, New Guinea.



*Wildcat,
Great information, what is your source ?*

*Guys, 
I am extremely busy with work, family and animals at this time. I have been able to put
together horse power ratings for the Allison V-1710-81, 83, 85 that were standard in
1942 and 1943. I hope to post this information in the next two days.

All the best and may God bless all, Jeff *

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## CORSNING (Jan 7, 2019)

Schweik said:


> Interesting, but were they in combat much? Were they still racking up victories in 1944? My understanding for the Pacific (as distinct from the CBI) was that most US P-40 units were kind of out of the game except for CAP (patrol over airfields etc.) because they longer had the range to reach Japanese targets. I know Australian Kittyhawk units were still getting some victories through 1944, I believe New Zealanders had already switched to Corsairs in 1943 (though they were no longer encountering many enemy planes anyway and I don't think made any victory claims with them).



No time to elaborate (see previous post)

AHT:
January 1, 1944- "In the war against Japan the Army is using 630 P-40s out of a total of 1765 fighters."


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## Wildcat (Jan 8, 2019)

CORSNING said:


> *Wildcat,
> Great information, what is your source ?*
> 
> *Guys,
> ...


Hi Jeff, I got that info straight from the squadron Operations record book.

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## CORSNING (Jan 8, 2019)

Thank you Wildcat. If you do not mind, I will add that to the P-40 timeline
I have put together for posting at a later date.


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## Wildcat (Jan 8, 2019)

Your welcome, glad it was of use. If you need any other dates for RAAF P-40 usage I'll be happy to look for you.


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## CORSNING (Jan 8, 2019)

*Horse Power of the Allison V-1710-81 & -85 per the USAAF 1942/1943.*

*All the following information can be viewed on*
WWII Aircraft Performance

All my research is due to the spark to get started by the information posted
by Mr. Mike Williams and Mr. Neil Stirling. I would also like to thank Mr.
Henning Ruch for renewed support and Mr. Greg Pascal for the confidence
and support to start posting. Thank you all.

All the following information comes from the War Department, Army Air
Corps./Forces, Materiel Center/Division/Command....one or the other.
All reports were addressed; Wright Field, Dayton, Ohio.

All figures for horsepower are at a manifold boosting of 57"Hg.

*P-39N-1 42-4400 (V-1710-85/E-19)*
From Report Serial No. FS-M-19-1510-A dated November 24, 1942.
1355 hp./S.L.
1390 hp./7,500 ft.
Graph accompanying Report serial number FS-M-19-1487-A
1295 hp./S.L.
1420 hp./9,700 ft.
"Horsepower obtained from power curve V-1710-83 and -85 dated September
19, 1942 (2,23:1 propeller gear ratio; 9.6:1 blower gear)."

*P-40N-1 42-9987 (V-1710-81/F20R)*
From Report Serial No. FS-M-19-1535-A dated January 30, 1943.
Speed trials:
1415 hp./2,960 ft.
1480 hp./10,550 ft. Full throttle height.
Climb trials:
1400 hp./S.L.
1450 hp./5,000 ft.
1480 hp./8,000 ft. Critical altitude.
Graph from P-39N-1 listed above shows the following results:
1385 hp./S.L.
1480 hp./10,550 ft.
"Horsepower obtained from power curve V-1710-81, 83 & 85 dated October
28, 29, 1942 (2:1 propeller gear ratio; 9.6:1 blower gear)."

*P-51A 43-6007 (V-1710-81/F20R)*
From Report Serial No. PHQ-M-19-1576-A dated April 2, 1943.
1480 hp./5,000 ft.
1480 hp./10,400 ft.
Those figures match perfectly with the accompanying graph referencing
FS-M-19-1576-A
1480 hp./S.L.
1480 hp./10,400 ft. Full throttle height.
"Horsepower obtained from power curve V1710-91, 83 & 85 dated October
28, 29, 1942 (2:1 propeller gear ratio; 9.6: 1 blower gear)."

Good night guys hope to hear from all tomorrow, Jeff

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## CORSNING (Jan 9, 2019)

Wildcat said:


> Your welcome, glad it was of use. If you need any other dates for RAAF P-40 usage I'll be happy to look for you.



In the WW2 fighter timelines I have put together I am modifying them to include delivery
dates, first date operational and first combat date (if known). Any information you may
have on any version of any of the fighter's first operational status with the RAAF would
be greatly appreciated.
No pressure mate, I greatly appreciate the information you have already given.


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## CORSNING (Jan 9, 2019)

Thank you all for a great discussion. I am thankful because these discussions
force me to dig through my files and others more deeply, a great learning 
process.
I was recently forced to study these aircraft more closely and stumbled upon
an interesting note that I apparently had not caught before. ...The P-40N-1
was tested with external gas tank shackles in place. P-40F 41-13635 in report
Ser. No. FS-M-19-1578-A dated April 3, 1943 showed an increase of speed at
full throttle height of 8.5 mph. Speed was increased from 365.5 mph to 374 mph
at 18,100 ft. by the removal of the shackles (belly sway braces). This all mean the
speed of the P-40N-1 from sea level to FTH should be increased about 8 mph.
That would put the true war emergency maximum speeds of the P-40N-1 in clean
condition around 340 mph./S.L. and 386 mph./10,550 ft. 
Just food for thought.

*P-39N-1* @ 7,301 lb. .[* P-40N-1* @ 7,413 lb. ]. *P-51A* @ 8,000 lb.

Altitude / Speed / Climb
Meters / MPH / FPM
S.L........344 / 3980 .[ 332 / 3520 ]. 376 / 3500
1,000..362 / 4145 .[ 345 / 3600 ]. 387 / 3625
2,000..381 / 4220 .[ 360 / 3680 ]. 400 / 3750
3,000..398 / 3940 .[ 375 / 3465 ]. 412 / 3405
4,000..394 / 3460 .[ 375 / 2965 ]. 413 / 2925
5,000..388 / 3060 .[ 373 / 2480 ]. 410 / 2455
6,000..382 / 2985 .[ 367 / 2025 ]. 405 / 2025
7,000..376 / 2230 .[ 362 / 1635 ]. 399 / 1605
8,000..367 / 1745 .[ 356 / 1265 ]. 389 / 1160
9,000..356 / 1310 .[ 348 / -.940 ]. 367 / -.765

Full Throttle Height: 398.5 mph./2,957 m. .[ 378 mph./3,215 m. ]. .415 mph./3,170 m.
Critical Altitude: 4360 fpm./2,225 m. .[ 3720 fpm./2,438 m. ]. .3785 fpm./2,255 m.

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## Kevin J (Jan 9, 2019)

CORSNING said:


> Thank you all for a great discussion. I am thankful because these discussions
> force me to dig through my files and others more deeply, a great learning
> process.
> I was recently forced to study these aircraft more closely and stumbled upon
> ...



Okay, so you tape the gun blast tubes to get these figures and when you enter combat and fire them then that takes off lets say 12 mph. In the case of the P-40N, you add the fuel tank back in and reinstate 2 guns, maybe another 6 mph loss. Then you need a dust filter, perhaps another 6 mph loss. Before you know it the crate you're flying is only doing 354 mph. Remove the belly tank shackles, I don't think so, because that's why you want the P-40N, for the range with the belly tank was better than the Spitfire VIII. As for that 398.5 mph for the Cobra, the report states that cooling requirements weren't met, so that's not something the Russians would have had to worry about in their standard ground level winter temperature of -20c. Did the USAAF use the P-51A in the CBI as a fighter, hell no, the P-40N was more manoeuvrable and speed was adequate for the task of a fighter; they used the P-51A as a fighter bomber and for counter air. Speed isn't everything.


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## Schweik (Jan 9, 2019)

P-39N had excellent speed and climb down low though that is clear

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## CORSNING (Jan 9, 2019)

Kevin J said:


> Okay, so you tape the gun blast tubes to get these figures and when you enter combat and fire them then that takes off lets say 12 mph. In the case of the P-40N, you add the fuel tank back in and reinstate 2 guns, maybe another 6 mph loss. Then you need a dust filter, perhaps another 6 mph loss. Before you know it the crate you're flying is only doing 354 mph. Remove the belly tank shackles, I don't think so, because that's why you want the P-40N, for the range with the belly tank was better than the Spitfire VIII. As for that 398.5 mph for the Cobra, the report states that cooling requirements weren't met, so that's not something the Russians would have had to worry about in their standard ground level winter temperature of -20c.
> 
> *Well sir, I believe in comparing apples to apples, comparing all WW2 fighters in their
> interceptor mode condition. If you wish to converse about what happens when you
> ...


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## Shortround6 (Jan 9, 2019)

Trying to figure out how to make graphs,

Here is an attempt at Allison engine powers.





COuld be a little off, Please note that all the 8.80 supercharger gear engines track pretty well which is what I would expect. This is without RAM.
Upper limit at 25,000f t comes from an Allison chart for the -33 engine but doesn't seen out of line for climb numbers for later engines.

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## Schweik (Jan 9, 2019)

Do you have data on higher boost settings for the V-1710-33? I've never seen anything other than military power settings. Would very much appreciate a reference with page number if possible.


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## CORSNING (Jan 9, 2019)

Shortround6 said:


> Trying to figure out how to make graphs,
> 
> 
> .....Good luck and God speed sir. I haven't had any luck in that area either.


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## Shortround6 (Jan 9, 2019)

That 1700hp at sea level is a theoretical (or calculated ?) number but it does come from an Allison chart for the -33 engine. 

We are told that the Flying Tigers overboosted their engines but we are not told by how much. We are told the Russians over boosted their Tomahawk engines but not by how much, as did the British (and commonwealth) in the desert. This is possible limits on the engine if/when a squadron or pilot did use more than the factory limit. 

I don't believe Allison or the US military ever approved over boosting the -33 engine, please remember that Alison had to rebuild 277 of the very early -33 including new crankshafts just to get them cleared for the 1090hp rating at 13,200ft. Nobody in the US was in any hurry to push the engine any harder until they accumulated thousands of hours in service to see how well they standing up. Once they found they could extend the overhaul several times over the original rated life then perhaps they could seriously consider pushing the engine. 
On the -33 the reduction gear was a weak point and would not stand up very well to higher than normal powers. Strangely enough it was not usually the reduction gear itself that failed but the crankshaft right behind the front bearing. 

The Chart says 1700hp at 61in but it is dated 12-5-39, actual power due to charge heating or other problems may be the reason behind the later engines needing more inches of pressure to get similar power.

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## Schweik (Jan 9, 2019)

I've read all the same rumors but can never find any hard data on that for the Tomahawk. Is that from Vees for Victory? Can you give me the page number?

What do you think is a realistic WEP / boost / hp level for the V-1710-33?


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## CORSNING (Jan 10, 2019)

Shortround6 said:


> That 1700hp at sea level is a theoretical (or calculated ?) number but it does come from an Allison chart for the -33 engine.
> 
> *Great information Shortround, is there a site where this chart can be viewed?*


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## Greyman (Jan 10, 2019)

Shortround6 said:


> We are told that the Flying Tigers overboosted their engines but we are not told by how much. We are told the Russians over boosted their Tomahawk engines but not by how much, as did the British (and commonwealth) in the desert. This is possible limits on the engine if/when a squadron or pilot did use more than the factory limit.



I've brought this up before --- but with no automatic boost control -- the point is there is no real limit. It's whatever the pilot wants at that moment (depending on altitude). Inattentive or undisciplined throttle control is going to result in an 'overboosted' Tomahawk.

Now this could be intentional as well. Sort of a "_Well boys, we all know the book says we're limited to 5 minutes at 40 inches, but we're gunna do what we gotta do out there to get home._"


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## Schweik (Jan 10, 2019)

Some P-40s did have automatic boost control, though it was sometimes removed in the field.


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## tomo pauk (Jan 10, 2019)

CORSNING said:


> Great information Shortround, is there a site where this chart can be viewed?


Here.
From here.

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## DarrenW (Jan 10, 2019)

Shortround6 said:


> One estimate for the P-51 said that an extra 1000lb INTERNAL was good for 3mph speed loss. That may have been optimisc.



Grumman also said the very same thing about the F6F-3.


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## Shortround6 (Jan 10, 2019)

tomo pauk said:


> Here.
> From here.


 Thank you Tomo. 

I would note that the graph itself uses smaller boxes on the right side than on the left so it turns a curve into a straight line. This was common for a number of engine charts of the time. 

I would also note that some engine companies (or book writers) would try to compare _theoretical_ engine power at sea level as a way of comparing engines, The Merlin II for instance was supposed to make the equivalent of 1500hp at sea level at 2600rpm. Of course with 87 octane fuel it had zero chance of coming anywhere near that power level. 

Also please note this test was done using US 100 octane fuel which was pretty much 100/100 which is another reason the US did not going in for over boosting engines in 1940-41.


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## tomo pauk (Jan 11, 2019)

Shortround6 said:


> Trying to figure out how to make graphs,
> 
> Here is an attempt at Allison engine powers.
> 
> ...



FWIW, the -81 and similar engines were not always rated for 1125 HP at 15500 ft. Sometimes the rated altitude is stated as low as 14500 (14600?) ft, or even at 14200 ft (all without ram effect): link (scroll down a bit)

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## Schweik (Jan 11, 2019)

Maybe it depended on air temperature or the loaded weight


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## Milosh (Jan 24, 2019)

Schweik said:


> Maybe it depended on air temperature or the loaded weight



Why would loaded weight effect HP?


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