# The P-39 a Zero Killer???



## oldcrowcv63 (Apr 13, 2014)

Found a surprising entry in Lundstrom's *First Team the Guadalcanal campaign*, page 172 3. regarding Hap Arrnold's opinion of the P-39 based apparently on reports from Mac Arthur's air staff, presumably derived from Pilot reports. Maj. General Harmon (SoPac army commander) urged the war department to send P-38Fs to SoPac because of the P-39's unsuitability as a high altitude interceptor. His recommendation was endorsed by Under Sec. Nav. James Forrestal. F4F-4s were becoming rare at this time. Hap Arnold apparently stated in his 1949 memoir (*Global Mission*) the belief based on reports from MacArthur that the P-39 was achieving a 4 to one victory ratio over the Zeros and believed it to be superior to the F4F. This seems both an uninformed opinion of US fighter performance and a level of technical ignorance hard to understand. It also suggests he believed the reports coming from MacArthur without question which doesn't speak well for his judgment. As a figure whose career demands great respect, I want to give him the benefit of the doubt. All I can figure is that he was happy to defer to Mac's report because it allowed him to justify his desire to dedicate P-38 deliveries to the ETO. 

Any thoughts on P-39 vs A6M or even compared to the F4F that might mitigate what seems to me to be a gross misrepresentation of the Bell fighter's relative performance?


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## meatloaf109 (Apr 13, 2014)

Wow. 
Seriously?
That is all I have to say. 
It is possible at a low altitude and with the P-39's 20mm cannon a couple of kills might have been made. But history says not.


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## parsifal (Apr 14, 2014)

There is not a lot of evidence to support this claim. i found the following which might be of some use


"Airacobras clashed with the Zero on April 30, 1942 in a low level action near Lae, New Guinea. From May to August 1942 combats between Airacobras and Zeros took place on a regular basis over New Guinea. After the first few combats Lt. Col. Boyd D. Wagner wrote a report on the early actions. After commenting that the Zero outperformed the P-39 markedly in maneuverability and climb, Wagner commented on the relative speeds of the aircraft at low altitudes. According to Wagner: "_the Zero was able to keep up with the P-39 to an indicated 290 mph. At 325 indicated just above the water, the P-39 pulled slowly out of range." Wagner also commented that the P-39's performance above 18,000 feet was very poor. 

In later actions combat reports sometimes offer helpful insights into the relative performance of the two aircraft. Lt. Paul G. Brown chased a Zero at 12,000 feet. "He nearly stayed away from me at 350 mph" (Brown). In a low level action: "I indicated 320 mph straight and level at 1,000 feet. Zero kept me in range" (Royal). In another action on the same day Zeros encountered P-39s and P-400s at 21,000 feet. "Zeros stayed with the Airacobras. I dived 12,000 feet indicating 450 miles per hour and Zero stayed with me and followed me to ground level firing. Lt. Martin pulled him off me" (Price). "4 Zeros were over Kokoda and attacked us on the way home. We were barely able to out speed them at 10,000 feet. We were indicating about 350 mph in a very slight dive. Their probable speed 340 mph" (Egenes). 

From the Japanese side also comes confirmation that the Zero could hold its own with a P-39 in low-level speed. Sakai relates that on July 22, 1942 he chased a P-39 low over the sea and the P-39 was unable to pull away from him (Sakai, p. 137). The Airacobra was eventually forced to turn in order to take up a course to its base. In the ensuing dogfight Sakai shot the aircraft down. It was probably a P-400 of the 35th Fighter Group. 

This compilation of reports indicates the Zero was either equal to or close to the P-39 in speed at the altitudes of the various encounters. The P-39 was in turn up to 40 m.p.h. faster than the F4F-4 according to reports from the South Pacific Theater. There the Zero was found to be consistently faster than the F4F-4. There is a disconnect between the San Diego test results and multiple reports from the combat zone. 

Lest there be any doubt, crash intelligence reports show that the Zero 21s in use in the Southwest Pacific were close contemporaries of the Akutan Zero (No. 4593, completed 19 Feb. 1942). Many crash reports identify production dates for Zero 21s lost in the SWPA as February 1942 or earlier.With the exception of a single appearance by A6M3s (30 August 1942) all the Zeros in combat over Guadalcanal during the period under review were also Zero 21s. 

The field data reviewed by this study indicate that Zeros operated by the Japanese performed relatively better against the Wildcat and Airacobra than did the Zero tested at San Diego. If the comparative performance of the San Diego Zero understated the performance of a typical Japanese operated Zero, this strongly indicates the quantitative performance was also understated. This tends to verify the conclusions reached in the section reviewing U.S. test results. The reasons for this seem obvious. The San Diego Zero was in less than perfect aerodynamic condition and was not operated at its optimum engine capacity or with automatic mixture control engaged. The figures cited in Summary No. 85 and repeated by Mikesh and Reardon are inaccurate and too low to represent the true performance of the Zero in Japanese operations. 

I have been unable to establish the basis for the performance figures higher than the San Diego test results (332-336 m.p.h.) but lower than Sakai's (sources 5-7 in the section Conflicting Data). They are close to the first test results obtained at San Diego (335 m.p.h.) but those results were not deemed reliable. Absent the basis for these figures nor knowing the conditions that yielded them they are difficult to assess. 

Sakai distinguished between normal full power speed (316 m.p.h.) and over boost (345 m.p.h.). His normal full speed is exactly the same as the Zero's maximum speed given in the captured Japanese manual. The San Diego test report, while revealing that the San Diego Zero was not tested at over boost, does confirm Sakai's assertion that such a rating was available. Sakai has credibility that is primarily based on his personal familiarity with the Zero 21 aircraft. These additional factors only bolster his credibility. 

The evidence assembled strongly indicates that Sakai's version of the Zero's maximum speed (345 m.p.h.) is credible and probably the correct one. Additional support for this conclusion is found in an intelligence document issued in 1944: "Performance data given for the ZEKE Mk. 1 [Allied code name for the Zero 21] was obtained in actual flight tests. Although emergency speed obtained in tests was 328 m.p.h., calculations indicate a maximum speed of about 345 m.p.h. as possible for a short period of time" (Intelligence Summary No. 44-11)".

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## GregP (Apr 14, 2014)

When I met Saburo Sakai and bought an autographed print, I asked him how fast the Zero was. His reply was that, like all aircraft, it depended on altitude and the condition of plane, engine,and propeller. He said an A6M5 Model 52 (like the one we have at the Planes of Fame) could get to 355 mph at best altitude but was, of course, not that fast at sea level. He didn't really say 355 mph ... he said kph, but I converted.

Some few minutes later, he left to go for a ride in Bill Hane's P-51D and loved that! That was in the early to mid 1980's at the Champlin Fighter Museum in Mesa, Arizona (Falcon Field) ... now a defunct museum. For many years it was the home of the American Fighter Aces Association. I have fond memories of that place.

I still have the autographed print of him in a Zero over Mount Fuji.

Our Zero WILL go that fast, but doesn't most of the time except in a dive during mock dogfights. Right now, it is undergoing a complete overhaul of the airframe, but should be flying again in the October - November timeframe.

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## Juha (Apr 14, 2014)

oldcrowcv63 said:


> ...Any thoughts on P-39 vs A6M or even compared to the F4F that might mitigate what seems to me to be a gross misrepresentation of the Bell fighter's relative performance?



Again, JoeB's old answer:
_- Aviation (Aviation)
- - How good was Japanese aviation? (http://www.ww2aircraft.net/forum/avi...ation-730.html (How good was Japanese aviation?))
…
JoeB 01-13-2007 04:43 AM
No, it only covers to the end of the first set of Japanese offensives in that area around the beginning of March. For New Guinea I'm comparing the Japanese losses given in Sakaida "Winged Samurai" w/ the US claims and losses given in Hess "Pacific Sweep".

The 8th FG (P-39) claimed 45 enemy aircraft April 30-June 1 1942, 37 of them Zeroes, losing 26 P-39's in air combat almost all to Zeroes. They were the only Allied fighter unit at Port Moresby having relieved 75sdn RAAF (P-40) when they arrived. The unit opposing them was the Tainan Air Group, A6M's, with suffered 11 pilots KIA in the same period. So actually I misrecalled 1:3 before looking back at notes, sorry, it's more like perhaps 1:2 considering in this case some of the combats were over the Japanese airfields and they could have lost some planes w/ surviving pilots, though it's not mentioned in any specific accounts I know of._

F4F on the other hand, again according to JoeB:
_
- Aviation (Aviation) 
- - Tactics: Spitfire vs Zero (http://www.ww2aircraft.net/forum/aviation/tactics-spitfire-vs-zero-25562.html) 

…

JoeB	08-09-2010 04:40 AM

…F4F's v Zero contests of course varied case to case to but overall trend was less variable around 1:1 with >100 kills on each side in 1942, in a variety of situations (G'canal defense high altitude, low altitude, carrier battles, F4F escorts v Zero CAP's over convoys in Solomins, etc without appearing to change wildly, numbers tended to be similar on each side)._


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## Wildcat (Apr 14, 2014)

According to the excellent book "Eagles of the Southern sky" by Luca Ruffato Michael Claringbould, during the period 1 April to 15 November 1942, the Tainan Kokutai shot down 38 Airacobras for a loss of 12 Zero's (1 by collision). These are confirmed victories, not claims.

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## buffnut453 (Apr 14, 2014)

I really must get that book! Been on my wish-list for a while now. Thanks for the info Wildcat.


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## oldcrowcv63 (Apr 14, 2014)

In my mind the whole issue begs the question, "_What was Arnold's role in dedicating R&D to developing the turbo charger_?" Did he understand or was he willing to acknowledge the importance of the 2-stage SC? or was it just a political comment to denigrate/deflect any potential criticism of the army's reliance on a technology that wouldn't pay off until years too late? I can't help but wonder if feedback from SoPac and earlier from the FEAF pilots wasn't making waves and causing some folks to sweat at home in R&D circles?

Pars, those performance numbers are _eye-opening _for both the A6M and the F4F-4! Thanks for the detailed post.


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## oldcrowcv63 (Apr 14, 2014)

meatloaf109 said:


> *Wow.
> Seriously?*
> That is all I have to say.



Meatloaf, that was my exact reaction. That and a slight but perceptible dropping of my jaw and a muttered "WTF?".

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## varsity07840 (Apr 14, 2014)

Wildcat's post says it all in a nutshell. Confirmed victories vs claims. Truth be told the Tainan Group overclaimed as much as the Allies did during the New Guinea campaign. There were alot of politics at state during the period when the USAAF was being torn up in the Pacific. MacArthur was all PR and it shouldn't have surprised anyone, even back then that most if not all that he put out was BS. Nevertheless his positive comments about the P-39 gave Arnold some cover during a time when there was an uproar about inferior aircraft being sent into combat. Finally, while the P-39 vs Zero comparison is interesting, and, more than frequently discussed, the fact is that Harmon was not concerned with a fighter vs fighter problem as much as he was with a lack of high altitude performance to shoot down bombers. While the F4F was a very poor climber, at least when it got there it could operate
at the G4M's bombing altitude. The P-39 would fall out of the sky, if it ever got up there.

Duane

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## parsifal (Apr 14, 2014)

GregP said:


> When I met Saburo Sakai and bought an autographed print, I asked him how fast the Zero was. His reply was that, like all aircraft, it depended on altitude and the condition of plane, engine,and propeller. He said an A6M5 Model 52 (like the one we have at the Planes of Fame) could get to 355 mph at best altitude but was, of course, not that fast at sea level. He didn't really say 355 mph ... he said kph, but I converted.
> 
> Some few minutes later, he left to go for a ride in Bill Hane's P-51D and loved that! That was in the early to mid 1980's at the Champlin Fighter Museum in Mesa, Arizona (Falcon Field) ... now a defunct museum. For many years it was the home of the American Fighter Aces Association. I have fond memories of that place.
> 
> ...



You lucky sob. Im jealous as hell


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## vikingBerserker (Apr 14, 2014)

I am almost finished reading Bruce Gamble's Rabaul trilogy and in one of the them aircrew joked about the P-400 (export P-39) was nothing more then a P-40 with a zero behind it. I am sure there are a few valid kills using a P-39, but like they say even a blind squirrel finds an acorn every once in a while.


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## FLYBOYJ (Apr 14, 2014)

Juha said:


> Again, JoeB's old answer:
> 
> JoeB 01-13-2007 04:43 AM
> _No, it only covers to the end of the first set of Japanese offensives in that area around the beginning of March. For New Guinea I'm comparing the Japanese losses given in Sakaida "Winged Samurai" w/ the US claims and losses given in Hess "Pacific Sweep".
> ...






Wildcat said:


> According to the excellent book "Eagles of the Southern sky" by Luca Ruffato Michael Claringbould, during the period 1 April to 15 November 1942, the Tainan Kokutai shot down 38 Airacobras for a loss of 12 Zero's (1 by collision). These are confirmed victories, not claims.






varsity07840 said:


> Wildcat's post says it all in a nutshell. Confirmed victories vs claims. Truth be told the Tainan Group overclaimed as much as the Allies did during the New Guinea campaign. There were alot of politics at state during the period when the USAAF was being torn up in the Pacific. MacArthur was all PR and it shouldn't have surprised anyone, even back then that most if not all that he put out was BS. Nevertheless his positive comments about the P-39 gave Arnold some cover during a time when there was an uproar about inferior aircraft being sent into combat. Finally, while the P-39 vs Zero comparison is interesting, and, more than frequently discussed, the fact is that Harmon was not concerned with a fighter vs fighter problem as much as he was with a lack of high altitude performance to shoot down bombers. While the F4F was a very poor climber, at least when it got there it could operate
> at the G4M's bombing altitude. The P-39 would fall out of the sky, if it ever got up there.
> 
> Duane



Great information guys! So really, are we looking at a rough 1:2/ 1:3 kill ratio for the P-39 in this situation? I would so this coincides with JoeB's earlier post. Despite this situation with the P-39 vs. Zero, it seems the Japanese still lost the upper hand. This is what Wiki says about the Tainan Kaigun Kōkūtai:

Tainan Air Group - Wikipedia, the free encyclopedia

_"Over the next several months, Tainan aircraft based at Rabaul engaged in repeated dogfights with Allied aircraft, called the Cactus Air Force, based on Guadalcanal. The extreme distances required for the Tainan pilots to fly from Rabaul to Guadalcanal severely hampered the unit's attempts to establish air superiority over the island. The unit also continued to support bombing missions against Port Moresby. Between August and November 1942,* the Tainan lost 32 pilots killed in action.* Junichi Sasai was killed on August 26 and Toshio Ōta on October 21.

On November 1, 1942 the Japanese naval units in the Southeast Pacific were reorganized. The Tainan was redesignated as the 251 Air Group and reconstituted with replacement aircrews. *The 20 surviving pilots *of the Tainan were transferred to Japan to help form new fighter units. Bergerud says only 10 pilots were left and that the new unit was not called the "251st Air Group"._
It would be interesting to find similar data showing how the P-40 faired in the same arena.


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## gjs238 (Apr 14, 2014)

Sounds like someone is trying to dogfight A6M's and Ki-43's.


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## varsity07840 (Apr 14, 2014)

parsifal said:


> You lucky sob. Im jealous as hell



I sat next to Joe Foss on a flight back in 1970. I recognized him right away and asked his wife if that was indeed Joe Foss. He was quite nice and let me pump him with questions. I was in the Army at the time and in uniform he noticed my Air Crewman wings and we wound up having quite a chat.

Duane


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## GregP (Apr 14, 2014)

Another resounding numbers success. 

The real kill ratio is somewhere between 45 : 26 and 12 : 38, depending on which account you believe. Since the P-39 was maligned in the press after the war, many believe the 12 : 38 is gospel while others think it wasn't so bad after all and lean toward the 45 : 26.

Now that's what I call accuracy with a kill ratio is anywhere from 2 :1 to 1 : 3! Now that's nailing it down, isn't it?

In the reference that quotes the 1 : 3, I wonder where the author got his numbers. I have been searching for Japanese records for many years and have yet to find one, much less one that specifies confirmed victories instead of claims. In fact, I never even HEARD of a Japanese unit that ever mentioned claims versus confirmed victories. I haven't even seen anything in print anywhere that mentions Japanese claims versus confirmed victories unless it was written by western authors who rarely give sources for numbers. The Japanese themselves didn;t keep public records of combat victories in the air ... it was a record for the unit, not the individual.

Not saying Wildcat is wrong or his source is, I'm just wondering where the numbers came from ... for BOTH sets of numbers. not just one.


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## FLYBOYJ (Apr 14, 2014)

GregP said:


> Another resounding numbers success.
> 
> The real kill ratio is somewhere between 45 : 26 and 12 : 38, depending on which account you believe. Since the P-39 was maligned in the press after the war, many believe the 12 : 38 is gospel while others think it wasn't so bad after all and lean toward the 45 : 26.
> 
> ...



These days "Bloody Shambles" seems to be a great place to start.


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## tomo pauk (Apr 14, 2014)

oldcrowcv63 said:


> In my mind the whole issue begs the question, *"What was Arnold's role in dedicating R&D to developing the turbo charger?" Did he understand or was he willing to acknowledge the importance of the 2-stage SC? or was it just a political comment to denigrate/deflect any potential criticism of the army's reliance on a technology that wouldn't pay off until years too late?* I can't help but wonder if feedback from SoPac and earlier from the FEAF pilots wasn't making waves and causing some folks to sweat at home in R&D circles?
> 
> Pars, those performance numbers are _eye-opening _for both the A6M and the F4F-4! Thanks for the detailed post.



Re. bolded part: the experiments with turbocharger were undertaken in the USA from early 1930s, contrary to the experiments with 2-stage superchargers. After all, turbo-equipped engine _was_ a 2-stage engine. For the mechanically driven 2-stage S/C for the V-1710, the USAC/USAF will need to 1st show some love (=money, resources) to the Allison - they were burning the midnight oil just to get the single stage V-1710 in order, to have something to power an new generation of fighters. The 2-stage R-1830 was tested on some aircraft competing for the orders the P-40 eventually won, due to it's still single stage engine.
The unfortunate decisions to install turbo darn close to the engine, like in the P-37 and P-39*, and unlike in the P-43 (that one, again unfortunately, got he wrong engine in the nose) hampered reliability and grow potential of a single-engined fighter with V-1710 in the nose.
No fighter is going to do much good if the competent radar and command network is not supporting it. As atested by Japanese once the Allies started striking back. The waves made in the SoPAC sounded something like this: send more P-38s. They also got P-47s in mid 1943. Both turbo-outfitted A/C.

*no, the XP-39 (with turbo) was not good for 390 mph right from the box, despite being unarmed


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## oldcrowcv63 (Apr 14, 2014)

parsifal said:


> *You lucky sob. Im jealous as hell*





varsity07840 said:


> I sat next to Joe Foss on a flight back in 1970. I recognized him right away and asked his wife if that was indeed Joe Foss. He was quite nice and let me pump him with questions. I was in the Army at the time and in uniform he noticed my Air Crewman wings and we wound up having quite a chat.
> 
> Duane



Amen to Parsifal's and the same to Duane for his lucky seat selection. 

My closest call and missed opportunity to delve into the past came at the North Island O-Club circa 1971-2, when i met a retired USN Captain. I asked him what he flew and he replied 'Wildcats.' For some reason I was distracted, probably by a female patron or perhaps just struck dumb in awe, and never got a chance to probe at all and thus missed a potential gold mine of information. D*mn! The tales he might have told.


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## GregP (Apr 14, 2014)

Good one FlyboyJ!

Seeing a talk by Saburo Sakai was dumb luck on my part. 

I went to an art show at Champlin Fighter Museum almost by accident when a friend of mine couldn't go and gave me his tickets. I had no idea who would be there. I wasn't invited ... he was. It was a magic evening by chance because he had another pressing engagement.


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## Totalize (Apr 14, 2014)

I read that it was the U.S. Army that requested Bell remove the supercharger from the original P39 thereby forever limiting its high altitude performance. The U.S. army also had Bell reduce the fuel capacity of the Aircraft as well to make it lighter. The Air battles in the Pacific were often higher altitude fights which was put the P-39 at a distinct disadvantage. However, on the Eastern front the air battles often took place at low altitude. On this front the P-39 was a credible opponent and achieved I think better success there especially as a ground attack fighter. A number of Guards units only had P39's they liked it so much. I also read the Soviets requested the U.S. stop sending them P-40's and replace them with P39's.


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## FLYBOYJ (Apr 14, 2014)

GregP said:


> Good one FlyboyJ!
> 
> Seeing a talk by Saburo Sakai was dumb luck on my part.
> 
> I went to an art show at Champlin Fighter Museum almost by accident when a friend of mine couldn't go and gave me his tickets. I had no idea who would be there. I wasn't invited ... he was. It was a magic evening by chance because he had another pressing engagement.


I met him at Chino - 1978?


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## Juha (Apr 14, 2014)

GregP said:


> ...In the reference that quotes the 1 : 3, I wonder where the author got his numbers. I have been searching for Japanese records for many years and have yet to find one, much less one that specifies confirmed victories instead of claims. In fact, I never even HEARD of a Japanese unit that ever mentioned claims versus confirmed victories. I haven't even seen anything in print anywhere that mentions Japanese claims versus confirmed victories unless it was written by western authors who rarely give sources for numbers. The Japanese themselves didn;t keep public records of combat victories in the air ... it was a record for the unit, not the individual.
> 
> Not saying Wildcat is wrong or his source is, I'm just wondering where the numbers came from ... for BOTH sets of numbers. not just one.



My understanding is that the writers of "Eagles of the Southern sky" compared Japanese docus/official histories with Allied docus and the confirmed means Tainan victories that can be verified by US docus. I haven't see the book but that's what I have heard. Note that JoeB's figure is that of shorter timeframe.

Juha

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## oldcrowcv63 (Apr 14, 2014)

tomo pauk said:


> Re. bolded part: the experiments with turbocharger were undertaken in the USA from early 1930s, contrary to the experiments with 2-stage superchargers. After all, turbo-equipped engine _was_ a 2-stage engine. For the mechanically driven 2-stage S/C for the V-1710, the USAC/USAF will need to 1st show some love (=money, resources) to the Allison - they were burning the midnight oil just to get the single stage V-1710 in order, to have something to power an new generation of fighters. *The 2-stage R-1830 was tested on some aircraft competing for the orders the P-40 eventually won, due to it's still single stage engine.*
> The unfortunate decisions to install turbo darn close to the engine, like in the P-37 and P-39*, and unlike in the P-43 (that one, again unfortunately, got he wrong engine in the nose) hampered reliability and grow potential of a single-engined fighter with V-1710 in the nose.
> No fighter is going to do much good if the competent radar and command network is not supporting it. As atested by Japanese once the Allies started striking back. The waves made in the SoPAC sounded something like this: *send more P-38s*. They also got P-47s in mid 1943. Both turbo-outfitted A/C.
> 
> *no, the XP-39 (with turbo) was not good for 390 mph right from the box, despite being unarmed



In this particular case it was just "send *some* P-38s" fifteen of which finally arrived about 3 months later (~November 1942). 

Based upon earlier similar discussion in other threads, it seems the alternate option to develop and/or install a *Single Stage, Two Speed Super Charger* was not pursued because that would have necessarily meant sacrificing some of the Allison 1710's low altitude performance to gain a marginal improvement in performance at a slightly higher altitude.


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## eWildcat (Apr 14, 2014)

gjs238 said:


> Sounds like someone is trying to dogfight A6M's and Ki-43's.



I guess they didn't even have to try to dogfight to get into trouble : when your plane does nothing better than the enemy plane, except perhaps rolling at some speeds, you're bound to having a quite hard time.
Considering the very poor high altitude performance of the P-39, the pilots weren't even sure they could use the big help provided by radar stations so as to ambush the enemy from above.


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## gjs238 (Apr 14, 2014)

eWildcat said:


> I guess they didn't even have to try to dogfight to get into trouble : when your plane does nothing better than the enemy plane, except perhaps rolling at some speeds, you're bound to having a quite hard time.
> Considering the very poor high altitude performance of the P-39, the pilots weren't even sure they could use the big help provided by radar stations so as to ambush the enemy from above.



Yes, but then how does one explain the success of the AVG with P-40's?


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## FLYBOYJ (Apr 14, 2014)

gjs238 said:


> Yes, but then how does one explain the success of the AVG with P-40's?



Tactics, tactics, tactics...

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## oldcrowcv63 (Apr 14, 2014)

FLYBOYJ said:


> Tactics, tactics, tactics...



Also, (and of course, in discussing the AVG, I am assuming we aren't talking about P-40s vs Zeros here) not all P-40s were the same. The P-40B/C initially delivered to the AVG was a bit lighter with somewhat better high altitude performance than many of those P-40Es employed in the PI, and later over Java, Australia and New Guinea. I don't know what weight saving measures might be implemented to improve the performance of the P-39/P-400 but my guess is that these were more limited than measures used to reduce the weight of the P-40E that appear to have been regularly if not universally adopted by the USAAF and RAAF.


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## FLYBOYJ (Apr 14, 2014)

oldcrowcv63 said:


> Also, (and of course, in discussing the AVG, I am assuming we aren't talking about P-40s vs Zeros here) not all P-40s were the same. * The P-40B/C initially delivered to the AVG was a bit lighter with somewhat better high altitude performance than many of those P-40Es employed in the PI, and later over Java, Australia and New Guinea. * I don't know what weight saving measures might be implemented to improve the performance of the P-39/P-400 but my guess is that these were more limited than measures used to reduce the weight of the P-40E that appear to have been regularly if not universally adopted by the USAAF and RAAF.



I don't think that would have made much of a difference, especially if you slowed one down to 180 knots and tied to "dance" with a Nate or Oscar. Bottom line, the AVG had it figured out and their combat record showed it.

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## oldcrowcv63 (Apr 14, 2014)

FLYBOYJ said:


> I don't think that would have made much of a difference, especially if you slowed one down to 180 knots and tied to "dance" with a Nate or Oscar. Bottom line, the AVG had it figured out and their combat record showed it.



I absolutely agree that tactics were the primary advantage and even a fully loaded P-40E with the right tactics was a better bet than a better performing aircraft without.

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## oldcrowcv63 (Apr 14, 2014)

of course even a marginal improvement in performance may provide an increase in tactical options as well as improve survival or victory probability in a fight. Else why would the experienced pilots implement such weight reduction measures?


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## eWildcat (Apr 14, 2014)

gjs238 said:


> Yes, but then how does one explain the success of the AVG with P-40's?



What was said : tactics, clever use of a net of observers by Chennault, lighter P-40s which could fly a bit higher than their opponents if warned soon enough. Add to this Japanese aircraft that often flew lower than what happened at Guadalcanal, a higher proportion of Ki-27s instead of the better Ki-43s and A6Ms, and the possibility to retreat to another airfield when things got too bad (or you wanted to cause some deception, something Chennault liked to do to compensate for inferior forces).

Another factor that may be overlooked is that the P-39s in 1942 had a lot of teething problems. It seems the P-40s were a lot more reliable.


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## tomo pauk (Apr 14, 2014)

oldcrowcv63 said:


> In this particular case it was just "send *some* P-38s" fifteen of which finally arrived about 3 months later (~November 1942).
> 
> Based upon earlier similar discussion in other threads, it seems the alternate option to develop and/or install a *Single Stage, Two Speed Super Charger* was not pursued because that would have necessarily meant sacrificing some of the Allison 1710's low altitude performance to gain a marginal improvement in performance at a slightly higher altitude.



The V-1710 already have had a single stage supercharger. Installing a two-speed gearing for the S/C would've improved the low altitude performance, especially the 15 minute rating (military power). The dedicated low-altitude V-1710-87, that was installed only in the A-36s, was good for 1325 HP at ~2500-3000 ft (no ram;military power), vs. ~1100 at same altitude for the V-1710-39 (installed on P-40D/E, Mustang I) and likes (V-1710-35 and -63, installed in P-39C/D/F/K/L).

The V-1710s that received increased supercharger speed through use of 9.60:1 gearing were the ones that offered better power at altitude, while sacrificing low alt power (under ~9500 ft, including take off power) against latest engines with 'old' supercharger gearing (8.80:1). The dedicated low-alt V-1710-87 have had S/C gearing of 7.84:1. 

Two-speed superchargers offer a far better flexibility than single-speed ones. It was not pursued by Allison, despite a request by NAA for the P-51, since they already have had hands full with both designing and ramping up production of wide range of V-1710s. They were developing the fluid (hydraulic) coupling for auxiliary supercharger installed on 2-stage engines; the engine-stage still using single speed gearing. Fluid coupling, most widely used on Daimler-Benz engines, gives infinite number of supercharger gears.


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## muscogeemike (Apr 14, 2014)

Now I’m not saying the P-39 was a great success in the Pacific, but it did shoot down more then a “couple” of Zeros (as well as other Jap planes). If nothing else it was all we had and, like the F4F, “held the line” until better aircraft became available (in fact the P-39 was still in Combat at the end of 1943 and used in the Recon role to Nov 1944). The stats show it held its own with at least a 1:1 kill ratio in that theater, and there were Aces who downed all their kills in the Airacobra.

When judging the plane we must examine the P-39’s record with the Soviets. They had great success with the aircraft against the same German planes we faced over Europe, and they used it almost exclusively as an Air to Air fighter - not a “tank buster” as our history has told us for years. In fact the 37 mm cannon the plane carried was a pre war design and was not effective against the armor of most WWII tanks after 1941 (in fact no AP shells were ever supplied to the Soviets). Were they better pilots than ours? Of course not but the number of Germans shot down by them would seem to say we have miss-judged the P-39 some.


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## GregP (Apr 14, 2014)

Having had several former ALlison employees and factory reps visit while I was at Joe Yancey's Allison shop, I can tell you what THEY said.

They universally said (not all there at the same time) that Allison was a relatively small shop and did not have the money to pursue developments the only real customer did not want to pay for. They offered a 2-stage supercharger to the USAAF and USN separately, and more than once. Most of the former employees said they offered it either two or three times, and were always told, "No thanks, what we really want is the delivery of the V-1710-XX's that are on order!"

They DID have 2 sizes of impeller, done on their own, but that is a relatively low-cost part development.

When the customer wants a -89, you deliver a -89, not an experimental 2-stage unit. That would be breach of contract.

When they needed to fix issues, they got paid for doing that since Allison had told the War Department before ever signing contracts that some development would be required along the way as operational issues came to light.

It is also my understanding that the War Materiel Board removed the turbochargers from the P-39 and P-40, due to scarcity of some metals. They "saved" the high-altitude boost for the bombers ... B-17's and B-24's, and only left them in the P-38 fighters, of which they didn't build all that many. The USAAF was informed of the WMB's decision and passed it along to the contractors, as they had no choice in the matter. The WMB dispersed piece parts as they saw fit.


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## varsity07840 (Apr 14, 2014)

muscogeemike said:


> Now I’m not saying the P-39 was a great success in the Pacific, but it did shoot down more then a “couple” of Zeros (as well as other Jap planes). If nothing else it was all we had and, like the F4F, “held the line” until better aircraft became available (in fact the P-39 was still in Combat at the end of 1943 and used in the Recon role to Nov 1944). The stats show it held its own with at least a 1:1 kill ratio in that theater, and there were Aces who downed all their kills in the Airacobra.
> 
> When judging the plane we must examine the P-39’s record with the Soviets. They had great success with the aircraft against the same German planes we faced over Europe, and they used it almost exclusively as an Air to Air fighter - not a “tank buster” as our history has told us for years. In fact the 37 mm cannon the plane carried was a pre war design and was not effective against the armor of most WWII tanks after 1941 (in fact no AP shells were ever supplied to the Soviets). Were they better pilots than ours? Of course not but the number of Germans shot down by them would seem to say we have miss-judged the P-39 some.



My understanding is there is only one AAF pilot "credited" with 5 kills in a P-39. His name escapes me but I'm pretty sure he flew out of Guadalcanal. I don't think he survived.
Duane


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## parsifal (Apr 14, 2014)

muscogeemike said:


> Now I’m not saying the P-39 was a great success in the Pacific, but it did shoot down more then a “couple” of Zeros (as well as other Jap planes). If nothing else it was all we had and, like the F4F, “held the line” until better aircraft became available (in fact the P-39 was still in Combat at the end of 1943 and used in the Recon role to Nov 1944). The stats show it held its own with at least a 1:1 kill ratio in that theater, and there were Aces who downed all their kills in the Airacobra.



I think it was Grau Geist who posted some very intersting numbers as to what what types shot down how many Japanese aircraft. The figures are claims based, so it is virtually assured that they overstate the actual numbers of victories. GGs figures are based on the AAF own post war wash up reports. From memory, it credits the P-39 in th entire pacific with something like 240 air victories. In doing that, they lost something like 800 airframes.

So, the exchange rate is not 1:1. The numbers is what they is.


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## FLYBOYJ (Apr 14, 2014)

varsity07840 said:


> My understanding is there is only one AAF pilot "credited" with 5 kills in a P-39. His name escapes me but I'm pretty sure he flew out of Guadalcanal. I don't think he survived.
> Duane


Lt. William Fiedler, he was killed when his P-39 was stuck by a P-38, I believe while on the ground.



parsifal said:


> I think it was Grau Geist who posted some very intersting numbers as to what what types shot down how many Japanese aircraft. The figures are claims based, so it is virtually assured that they overstate the actual numbers of victories. GGs figures are based on the AAF own post war wash up reports. * From memory, it credits the P-39 in the entire pacific with something like 240 air victories. In doing that, they lost something like 800 airframes.*
> So, the exchange rate is not 1:1. The numbers is what they is.



Those losses were from all causes?


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## muscogeemike (Apr 14, 2014)

parsifal said:


> I think it was Grau Geist who posted some very intersting numbers as to what what types shot down how many Japanese aircraft. The figures are claims based, so it is virtually assured that they overstate the actual numbers of victories. GGs figures are based on the AAF own post war wash up reports. From memory, it credits the P-39 in th entire pacific with something like 240 air victories. In doing that, they lost something like 800 airframes.
> 
> So, the exchange rate is not 1:1. The numbers is what they is.



If all aircraft are scored by total lost to all causes, as you are doing, then no aircraft has the ratio it is credited with.

I've read that the Fin's claim their version of the Buffalo has the highest kill to loss ratio of any WWII fighter! You are hard pressed to find any US or Brit pilot who will say good things about it.

Again I don't say the airplane was a great success in the Pacific but it did contribute, men fought in it, won some, lost some, and lived or died flying it.

And, still, the different opinions of the Soviet pilots and the Western Powers towards the plane must reflect something. Many of the highest scoring Soviet Aces got many of their kills in the P-39, and no Western pilot scored close to their highest.


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## michaelmaltby (Apr 14, 2014)

"....Were they better pilots than ours? Of course not but the number of Germans shot down by them would seem to say we have miss-judged the P-39 some."

Not mis-judged, not fully appreciated how the Eastern Front low altitude arena played into the Airacobra's strengths .... plus pilots inclined to get dangerously close to their targets ... The P-39 was a perfect fit for the Soviets.


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## parsifal (Apr 14, 2014)

FLYBOYJ said:


> Lt. William Fiedler, he was killed when his P-39 was stuck by a P-38, I believe while on the ground.
> 
> 
> 
> Those losses were from all causes?



Yes, all causes. I confess that im not 100% sure of the total losses suffered by p-39s, but their air victory totals are not great. Atleast three squadrons were in combat more or less continuously in PNG in 1942-3, stretching over roughly an 11 month period. The general rate of attrition suffered by the allied air forces was in the vicinity of 10% per month. With a force structure of 90 aircraft, the P-39s are going to be losing or writing off about 9 aircraft per month, for a total loss of about 100 aircraft in that one TO alone. 

The US lost 22000 aircraft in air combat , and more than 25000 to other causes outside the US during the war. ive read they lost about 14000 aircraft iin the US itself in training accidents. Thats a total of around 61000 aircraft lost to all causes during the war. by comparison, Japanese losses were 45000, of which 17000 were not combat related. Germany lost somewhere between 75 and 110000 aircraft.

Just getting airborne will gurantee losses. Entering a disputed area like New guinea will guarantee losses on the ground and ihn the air. Operating in conditions where front lines are fluid, like the eastern front will ramp up losses even further

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## parsifal (Apr 14, 2014)

muscogeemike said:


> If all aircraft are scored by total lost to all causes, as you are doing, then no aircraft has the ratio it is credited with.
> 
> I've read that the Fin's claim their version of the Buffalo has the highest kill to loss ratio of any WWII fighter! You are hard pressed to find any US or Brit pilot who will say good things about it.
> 
> ...



whichever way you want to cut it, the p-39 did not do well in the pacific, as the pilots that flew them readily attest to. in the air, the exchange rate was somewhere between 2:1 and 4:1, depending on who to believe. On the ground, well no way of comparing with japanese losses. However, from April 42 on, japanese air assets were heavily outnumbered....by September it was in the region of 1000 to 140, so inevitably within the microciosm of that one TO, Japanese overall losses are going to be lower. they held many advantages in the TO....most important were interior lines, better aircraft, better pilots, at least in 1942. Working against them was numbers, far better allied logistics, improving allied tactics and hradually improving pilot skills


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## parsifal (Apr 14, 2014)

I had a look at pacific wrecks.com..... Pacific Wrecks - Bell P-39 Airacobra and there are 117 known losses for the p-39 in the pacific, wrecks from p-39s that were airborne at the time

Includes 25 wrecks of unknown origin and three wrecks of P-39s in RAAF service. Does not include non combat losses


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## tomo pauk (Apr 15, 2014)

GregP said:


> Having had several former ALlison employees and factory reps visit while I was at Joe Yancey's Allison shop, I can tell you what THEY said.
> 
> They universally said (not all there at the same time) that Allison was a relatively small shop and did not have the money to pursue developments the only real customer did not want to pay for. They offered a 2-stage supercharger to the USAAF and USN separately, and more than once. Most of the former employees said they offered it either two or three times, and were always told, "No thanks, what we really want is the delivery of the V-1710-XX's that are on order!"
> 
> They DID have 2 sizes of impeller, done on their own, but that is a relatively low-cost part development.



What was onther impeller, apart from the 9.50 in one, that was used on the V-1710s during the ww2?


> When the customer wants a -89, you deliver a -89, not an experimental 2-stage unit. That would be breach of contract.
> 
> When they needed to fix issues, they got paid for doing that since Allison had told the War Department before ever signing contracts that some development would be required along the way as operational issues came to light.
> 
> It is also my understanding that the War Materiel Board removed the turbochargers from the P-39 and P-40, due to scarcity of some metals. They "saved" the high-altitude boost for the bombers ... B-17's and B-24's, and only left them in the P-38 fighters, of which they didn't build all that many. The USAAF was informed of the WMB's decision and passed it along to the contractors, as they had no choice in the matter. The WMB dispersed piece parts as they saw fit.



The P-40 didnn't have the turbo in the 1st place, so it could not be removed.
The unarmed XP-39 was good for mazbe 370 mph, and was immediately sent to a full scale NACA wind tunel for drag cleanup tests. NACA determined that drag from coolers was excessive, ditto for turbo iinstallation. Thez also recomended installing a more shallow cockpit glazing and a smaller wing. In case the clean-up was undertaken, NACA estimated that speed would be better than 390 mph above 20000 ft. Same speed was expected with altitude rated V-1710 (ie. single stage engine) at 15000 ft.
Once the armament and other combat equipment was installed, there is no wonder that P-39s were barely able to top 370 mph, until Allison introduced engines with 9.60:1 S/C drive ratio.


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## GregP (Apr 15, 2014)

The Allison had a 10.25" impeller on the -143 (G6R) and -145 (G6L). It also had it on the -147 / 149 G9 R/L. Joe Yancey has both for sale and overhaul, so they aren't gone yet/

All the WWII Allisons had a 9.5" impeller.

According to Don Berlin's son, the P-40 was designed for a turbo, but was never allowed to have one until late in the game when ONE was supposedly made and performed VERY well. Unfortunately, I can't find any record of it's actual existence, so it is heresay from the Designer's son. I think it might have happened, but have no real feeling or proof either way.

Because you can't find it doesn't mean it never happened ... it means you have no proof as yet, and I don't. Will continue to look but, frankly, whether he made one or not ... it never made production, so the significance is low either way ... unless performance figures say differently.

Since I can't find proof of it's existence, I certainly can't find any performance data! ... and make NO claims about it on my own.

It remains an interesting "what if" to me, but is likely to never surface if it hasn't already. I give it little credence, but hope it is so in the end. That, at least, would enhance Don Berlin's importance as a fighter designer WAY past time. Might never happen unless someone makes a discovery of long-buried documents.


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## Jabberwocky (Apr 15, 2014)

At low altitudes, the P-39 could be a peach of a fighter. Just ask the VVS.

The RAF found that the P-39C they tested was able to hang with a Spitfire Mk V in a climb under 10,000 ft and was faster than the Spitfire up to about 15,000 ft, but was not as nimble in switching direction (being comprable to a Mk I with fabric ailerons) or as good in the turn.

Of course, the P-39D added a heap of weight to the design (somewhere from 750-1100 lbs) with heavier armament, armour, self sealing tanks, plumbing for D/Ts and the like.

Still, the US TAIC P-39D-1 (using 52" manifold pressure giving 1325 hp sea-level/1150 at 11,200 ft, [70" was causing detonation]) vs A6M2 test (possibly slightly underperforming with only 900 hp instead of 955 hp) showed the P-39D-1 was capable of accelerating away from the Zero at any height, albeit it more slowly about 15,000 ft, and could peg it in a climb up to about 12,500 ft. Beyond this the Zero "walked away" (not encouraging phraseology for an official test).


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## wuzak (Apr 15, 2014)

GregP said:


> The Allison had a 10.25" impeller on the -143 (G6R) and -145 (G6L). It also had it on the -147 / 149 G9 R/L.



A number of the two stage engines had the 10.25" engine stage supercharger. The auxiliary stage was 12.1875".

There were some single stage engines with that impeller size - the -57 for one. Looking at Vees for Victory it would appear that most of teh G-series had the larger impeller.




GregP said:


> According to Don Berlin's son, the P-40 was designed for a turbo, but was never allowed to have one until late in the game when ONE was supposedly made and performed VERY well. Unfortunately, I can't find any record of it's actual existence, so it is heresay from the Designer's son. I think it might have happened, but have no real feeling or proof either way.



It's de ja vu all over again!

The P-40 was never design to carry a turbo and never did. The definition of the P-40 project was a Hawk 75 airframe with a single speed, single stage, altitude rated V-1710 and no turbo. The reason for this was that the turbo in the XP-37 and YP-37 was unreliable and the performance was less than spectacular.

The P-40 project may have been the impetus behind the development of the altitude rated engine.

The XP-53 sort of looked like a P-40. It was to have an IV-1430 without a turbo. But since that engine was behind badly, the V-1650-1 was substituted, and it became the XP-60.

Then followed proposals for two turbocharged versions - both with the V-1710, but with different turbos. These were the P-60A (with GE turbo) and P-60B (with Wright turbo). On initial inspections the XP-60A's turbo installation was deemed to be a fire hazard, and had to be reworked. The XP-60B never happened.

There was also a proposal for the Chrysler IV-2220, the P-60C, but because that engine was also behind they stuck in an R-2800.

The XP-60 was later re-engined with the V-1650-3 as the XP-60D, but it was thought that the Merlin was needed elsewhere and it did not proceed past the prototype.

And, lastly, there was the XP-60E - another R-2800 powered version, by now bearing no resemblence to the P-40.

The XP-60A was estimated to have a top speed of 420mph, but this was never confirmed.


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## muscogeemike (Apr 15, 2014)

For the third time I don’t say the Airacobra was a success in the Pacific, I say it contributed. Just like the P-47 after the P-51 arrived in numbers, the P-39’s mission changed and it served a useful function, probably due to it being there and we had to use it.

I recommend FIRE IN THE SKY, The Air War in the South Pacific, by Eric. M. Bergerud; and Osprey’s Aircraft of the Aces # 36, P-39 Airacobra Aces of World War 2.

FIRE IN THE SKY is a very good read (much like reading a novel) and the best analysis of the Air War in that area, on both sides.

Why didn’t the US Pilots lighten the plane as the Reds did? Removing the .30’s and ammo, could have been done easily and two .50’s (forget the 37mm, replace it with a 20mm if possible - another .50 if not) on center line would have been adequate against the lightly armored Japanese planes. Of course I’m “Monday morning quarterbacking” but it seems to me that since performance was of paramount interest our Pilots would have modified the planes to achieve better performance - especially since their lives depended on it.
The men in the field did many modifications to other aircraft without approval for the brass, why not with the P-39?


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## FLYBOYJ (Apr 15, 2014)

muscogeemike said:


> FWhy didn’t the US Pilots lighten the plane as the Reds did?



In theater, that would not be a decision made by pilots; that decision would normally come from a maintenance officer with concurrence from the manufacturer - that's not to say that "custom" mods weren’t done in theater (some mods very “illegal” and somewhat dangerous), and few were actually done by "pilots."


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## Totalize (Apr 15, 2014)

FLYBOYJ said:


> In theater, that would not be a decision made by pilots; that decision would normally come from a maintenance officer with concurrence from the manufacturer - that's not to say that "custom" mods weren’t done in theater (some mods very “illegal” and somewhat dangerous), and few were actually done by "pilots."



I can't speak for the U.S. Army Air Corps practices in that particular theater of War but in the RCAF and Probably for the RAF the Pilot was the commander of the ship not his maintenance crew. He was the one that risked his life and died if there was a malfunction. It was common practice for a pilot to provide feedback to his ground crew after a flight in the aircraft that something was not working properly and needed fixing and that he expected it to be fixed ASAP assuming time and supplies permitted. If not the ground could report the a/c not ready for flight. After all they didn't want to see the pilot put into a dangerous situation. Besides regulations forbade it. 

I suspect that after a number of dog fights the Pilots would collectively discuss was was working and what was not in combat. So for instance in this case I would not be surprised if they collectively got together and told the ground crew that the 37mm cannon was of no use in combat because of it's excessively slow rate of fire and propensity to jam in combat.Of course I am speaking hypothetically here and using the 37mm gun as an example of something inherently wrong with the a/c that needed fixing. This feedback could only be provided by the pilots not the maintenance crew. The Maintenance Officer I would suspect as well would want to accomodate his pilots and based on their feedback would try and make the necessary mods by perhaps advising the manufacturer of the problem and asking for a solution or alternative to using the 37mm cannon. So really changes and mods were initiated by the pilots and based on their feedback were/were not physically implemented by the ground crew.


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## FLYBOYJ (Apr 15, 2014)

Totalize said:


> I can't speak for the U.S. Army Air Corps practices in that particular theater of War but in the RCAF and Probably for the RAF the Pilot was the commander of the ship not his maintenance crew. He was the one that risked his life and died if there was a malfunction. It was common practice for a pilot to provide feedback to his ground crew after a flight in the aircraft that something was not working properly and needed fixing and that he expected it to be fixed ASAP assuming time and supplies permitted. If not the ground could report the a/c not ready for flight. After all they didn't want to see the pilot put into a dangerous situation. Besides regulations forbade it.



I could tell you that even a RAF or RCAF pilot would be limited on what he could have his crew do with regards to aircraft modification, repairs within approved maintenance manual data is a different story. I know back then, as in today's world, no modifications are done unless there is some kind of approved "engineering data." I've worked with both the CAF and RAAF during the past 20 years and they seem more strict on defining what types of mods or repairs involves engineering approval then the USAF and USN. What you describe in your 2nd paragraph is just about how it worked back then and even in today's world, but nothing happens "leagally" until the paperwork is approved.

I served in the USNR as a maintainer and on at least two occasions I was asked (then ordered) to attempt to repair something that was not within my maintenance authority - both times I told the powers to be to eff off and I'll be ready to stand mast with them, both times those parties stood down.

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## gjs238 (Apr 15, 2014)

Was that the procedure followed by the crew of Old 666?


_View: https://www.youtube.com/watch?v=6Im086TCu3I_


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## muscogeemike (Apr 15, 2014)

Totalize said:


> I can't speak for the U.S. Army Air Corps practices in that particular theater of War but in the RCAF and Probably for the RAF the Pilot was the commander of the ship not his maintenance crew. He was the one that risked his life and died if there was a malfunction. It was common practice for a pilot to provide feedback to his ground crew after a flight in the aircraft that something was not working properly and needed fixing and that he expected it to be fixed ASAP assuming time and supplies permitted. If not the ground could report the a/c not ready for flight. After all they didn't want to see the pilot put into a dangerous situation. Besides regulations forbade it.
> 
> I suspect that after a number of dog fights the Pilots would collectively discuss was was working and what was not in combat. So for instance in this case I would not be surprised if they collectively got together and told the ground crew that the 37mm cannon was of no use in combat because of it's excessively slow rate of fire and propensity to jam in combat.Of course I am speaking hypothetically here and using the 37mm gun as an example of something inherently wrong with the a/c that needed fixing. This feedback could only be provided by the pilots not the maintenance crew. The Maintenance Officer I would suspect as well would want to accomodate his pilots and based on their feedback would try and make the necessary mods by perhaps advising the manufacturer of the problem and asking for a solution or alternative to using the 37mm cannon. So really changes and mods were initiated by the pilots and based on their feedback were/were not physically implemented by the ground crew.



As you say, any of us who have been there know that much of the book goes out the window in combat. Common sense says that survival would guide at least some Pilots and their input would be heard by commanders and Maint. people. USAAF units in New Guinea and Guadalcanal were a ways away from the flag pole.


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## FLYBOYJ (Apr 15, 2014)

gjs238 said:


> Was that the procedure followed by the crew of Old 666?



They were probably done illegally, as were the first cannon armed B-25s and torpedo armed PBYs


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## FLYBOYJ (Apr 15, 2014)

muscogeemike said:


> As you say, any of us who have been there know that much of the book goes out the window in combat.



Back then, on many occasions - in today's world, you better be able to justify your actions, and even then there are many who would rather preserve their career then make a decision regarding the field alteration of a weapons system. BTW I speak for aircraft only....


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## bobbysocks (Apr 15, 2014)

muscogeemike said:


> Why didn’t the US Pilots lighten the plane as the Reds did? Removing the .30’s and ammo, could have been done easily and two .50’s (forget the 37mm, replace it with a 20mm if possible - another .50 if not) on center line would have been adequate against the lightly armored Japanese planes. Of course I’m “Monday morning quarterbacking” but it seems to me that since performance was of paramount interest our Pilots would have modified the planes to achieve better performance .



you have to watch when you start "lightening" as weight isnt your only consideration. you have to work within an envelope of a planes balance point. it can neither be too heavy in the nose or the tail or your flight characteristics go out the window and the plane can become unsafe for flight. that 37mm and its ammo weigh a considerable amount...replacing it with a 50 may make the plane tail heavy. you really can use the soviets as to what can be done safely and sanely to an ac. they had practices that would make other pilots and crews of most every other air force shutter. the soviets took down a lot of german planes but they lost a heck of a lot doing it.

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## FLYBOYJ (Apr 15, 2014)

The P-39 was CG sensitive - it actually had a lateral and vertical CG, something you commonly see in helicopters.


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## tomo pauk (Apr 15, 2014)

bobbysocks said:


> you have to watch when you start "lightening" as weight isnt your only consideration. you have to work within an envelope of a planes balance point. it can neither be too heavy in the nose or the tail or your flight characteristics go out the window and the plane can become unsafe for flight. that 37mm and its ammo weigh a considerable amount...replacing it with a 50 may make the plane tail heavy. you really can use the soviets as to what can be done safely and sanely to an ac. they had practices that would make other pilots and crews of most every other air force shutter. the soviets took down a lot of german planes but they lost a heck of a lot doing it.



My understanding is that Soviets never replaced the 37mm cannon, but deleted the wing LMGs and their ammo. That was far less CoG-sensitive thing to do, it also buys some speed through less drag. They also removed some of it's radio equipment (the P-39 carried up to 3 radio sets regularly), and probably some of it's armor.

An interesting tidbit for P-40 fans: link


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## oldcrowcv63 (Apr 15, 2014)

Here is a description of modifications to a P-40E to reduce its combat weight of the 49th PG defending Darwin in 1942, authorized by the squadron CO. Note the _moment_ contribution tabulated for each bit of equipment. The engine's position was apparently adjusted to compensate for the configuration changes that evidently included removal of two HMGs and radio, reduction of ammo, and fuel and other odds and ends. Some 49th PG pilots reportedly fought with some subset of these changes. The atached apparently describe changes to an aircraft made in June, 1942 even though the date is 9/8/42

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## GregP (Apr 15, 2014)

Hi Wuzak,

Yes, it IS deja vous all over again. 

I stated clearly that the designer's son made the statement, not me. There IS room for a turbocharger in the P-40 if you place it correctly, and Mr. Berlin said they were allowed to build ONE. As stated by me plainly above, I can find no record of it. So it may or may not be true, I make no claim either way. When I pass on what others have said, you don't have to try to convince me of one side or the other ... I already have an opinion (not posted in here) and that won't change.

I've stuck my head into the belly of a P-47 and have seen the ducting up close and personal. I've looked in the P-40, and have actually gotten into the rear fuselage, and think you could locate a turbocharger in there, too. But I haven't bothered and won't bother to try any calculations for it since nobody in the world wants to DO it to a very valuable stock, flyable P-40. 

We all know you could certainly do it with smaller modern turbo, but they didn't have them in WWII.

To me, the easiest solution to the low-to-medium altitude P-40 performance was a 2-stage Merlin. That would definitely have fit and should have been tried, but apparently wasn't. Perhaps they simply didn't think the P-40 was enough of a fighter to merit the expense of the project ... I don't know and don't care to speculate about why it was never tried.


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## oldcrowcv63 (Apr 15, 2014)

Here is the cover sheet with the earlier date. Note the original loaded weight of the P-40E could be around 8,300 pounds. so the weight saving was substantial. I thought deletion of any of the 4 .30s of the P-39 would be unlikely and replacing the 37mm with a 20mm, if that was the original configuration wouldn't buy all that much weight saving. Dunno, just spit-balled it.


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## muskeg13 (Apr 15, 2014)

A Zero killer? Hardly, unless the Japanese pilot in a fit of laughter lost control of his aircraft and crashed. Pacific P-39/P400s weren't even effective against Japanese bombers. The wartime diary of Cactus Air Force pilot CPT Robert Ferguson, which became "Island of Fire" and Martin Caidin's "The Rugged, Ragged Warriors" record the demerits of Pacific Aircobras in great detail. 

There was more to the Gen Arnold story. After suffering severe losses and extremely poor conditions on the ground, while attempting to fight with an aircraft completely unsuitable for air-to-air combat, the Army commander of the Cactus Air Force was summoned to Espiritu Santo. CPT Dale Brannon met the extremely angry Arnold who demanded to know why the Army fighters on Guadalcanal were not scoring as many kills as the Navy Wildcats, and were not even scoring as many kills as were being claimed by other P-39 units in the theater of operations. When Brannon started to explain the P-400 wasn't even as good as a "real" P-39, Arnold cut him off, calling his whole unit "nothing but a bunch of cowards!" Hyped up by wild unit kill claims, MacArthur's BS and fictional HQ 13th AF staff reports, Arnold refused to believe Army pilots were attempting to fight the Japanese with inferior aircraft.

For all of its faults as an interceptor or air superiority fighter, the P-39/P-400 excelled in the ground attack role. Three P-400s saved the day, and possibly the whole Guadalcanal Operation, on 14 September 1942 at Bloody Ridge.

http://67tfs.org/Guadalcanal.html

Wings at War Series, No. 3: Pacific Counterblow; Chapter 3

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## FLYBOYJ (Apr 15, 2014)

muskeg13 said:


> A Zero killer? Hardly, unless the Japanese pilot in a fit of laughter lost control of his aircraft and crashed. Pacific P-39/P400s weren't even effective against Japanese bombers. The wartime diary of Cactus Air Force pilot CPT Robert Ferguson, which became "Island of Fire" and *Martin Caidin's "The Rugged, Ragged Warriors" record the demerits of Pacific Aircobras in great detail. *


Not necessarily disagreeing with you but take anything by Caidin with a grain of salt, he's been known to stretch the truth on more than one occasion.


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## RpR (Apr 15, 2014)

Here is a page that lists air to kills by type and theater.

Warbirds and Airshows- WWII US Aircraft Victories

Whether one believes it or does not, it was written by person with more info than this forum has.


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## GregP (Apr 15, 2014)

As you will note, that list is supposed to be air-to-air victories only, and the totals disagree with Ray Wagner and a few others I have come across, but thank you for the link!

Now I have some comparisons I can think about between sources ... but I notice that Mr. Jackson doesn't give his sources. He might in the small print somewhere and I'll look for them myself at leisure.


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## muskeg13 (Apr 15, 2014)

> Not necessarily disagreeing with you but take anything by Caidin with a grain of salt, he's been known to stretch the truth on more than one occasion.



Understand. That's why I referenced Ferguson's book. It's a first-hand account by someone who was forced to face Zeros while saddled in an Aircobra. Nearly the whole book is an account of Aircobra vs. Zero, while it's just a chapter in Caidin's book...which seems to just restate what is in Ferguson's book. The Arnold story was in "Island of Fire," and wasn't known to Ferguson until after the war was over. Brannon was close lipped after being reamed by Arnold, not wanting to destroy unit morale completely, and he was posted away shortly after it occurred to take over a new (real Zero killing) P-38 squadron.

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## gjs238 (Apr 15, 2014)

muskeg13 said:


> <SNIP> For all of its faults as an interceptor or air superiority fighter, the P-39/P-400 excelled in the ground attack role. Three P-400s saved the day, and possibly the whole Guadalcanal Operation, on 14 September 1942 at Bloody Ridge.
> 
> http://67tfs.org/Guadalcanal.html
> 
> Wings at War Series, No. 3: Pacific Counterblow; Chapter 3



It's interesting how quickly the Prestone coolers were shot out of two of the three P-400's when performing ground attack/CAS.


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## oldcrowcv63 (Apr 15, 2014)

BobR said:


> Here is a page that lists air to kills by type and theater.
> 
> Warbirds and Airshows- WWII US Aircraft Victories
> 
> Whether one believes it or does not, it was written by person with more info than this forum has.



This forum's resources may run deeper than you realize. 
Looking at Jackson's victories page he cites near the top the instance of "_Ensign John Leppla, a SBD Scout Bomber Pilot, was credited with *7 kills* along with his gunner, which was more than any of the fighter pilots had at the time on the USS Lexington._"

Those are clearly claims vs confirmed victories. The number of VT (KATES) in the attacking force was 18. Leppla only claims engaging Kates. The Sho and Zui recovered 10 of these with 1 ditching at home plate. That's 11 total that returned to their carriers. leaving only the 7 claimed by Leppla. However others made claims as well including a confirmed Kate to VF-2's Ed Sellstrom. Only three VT were confirmed as destroyed in that attack, according to John Lundstrum (*First Team*) who used sources from both sides. 

Leppla who was KIA at Santa Cruz is credited with a total of 5 career victories. with one earned on the day he was shot down October 26, 1942. 

Conclusion: Jackson is tabulating claims not victories.


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## oldcrowcv63 (Apr 15, 2014)

My bad.. Further reading showed Leppla apparently fought A6M's as well but made no claims.. All told, the USN VB VS squadrons claimed 6 VF, 1 VB and 10 VT. Lundstrom could only confirm 1 VB and 3 VT. USN VF claimed 10 VF, 4 VB and 1 VT but only 3 IJN VB and 1 VT could be confirmed. During retirement USN VF scored on another Kate returning to its carrier. Total confirmed and accounted for is 16 VT leaving but two unaccounted for. Leppla was apparently given credit for 4 VT at Coral Sea and the one VF at Santa Cruz.


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## muscogeemike (Apr 15, 2014)

oldcrowcv63 said:


> Here is the cover sheet with the earlier date. Note the original loaded weight of the P-40E could be around 8,300 pounds. so the weight saving was substantial. I thought deletion of any of the 4 .30s of the P-39 would be unlikely and replacing the 37mm with a 20mm, if that was the original configuration wouldn't buy all that much weight saving. Dunno, just spit-balled it.



Yet that is what the Soviet’s did and had great success in the air to air role.
It is weird to me that US Pilots, known for not adhering to discipline or orders they didn’t like, couldn’t or wouldn’t lighten their P-39’s; while the Red Pilots, under one of the most ridged and brutal of governments, could modify their aircraft.


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## buffnut453 (Apr 15, 2014)

FLYBOYJ said:


> Not necessarily disagreeing with you but take anything by Caidin with a grain of salt, he's been known to stretch the truth on more than one occasion.



Entirely agree with you, Joe. I still have my copy of "Ragged, Rugged Warriors" which I purchased as a kid in Canada. That book first got me interested in the AVG but, over time, I've come to realize how many inaccuracies have been included in that book. I keep it for nostalgia, not as a source of accurate info about the early air war in the Far East.

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## Jabberwocky (Apr 15, 2014)

muscogeemike said:


> Yet that is what the Sovietï¿½s did and had great success in the air to air role.
> It is weird to me that US Pilots, known for not adhering to discipline or orders they didnï¿½t like, couldnï¿½t or wouldnï¿½t lighten their P-39ï¿½s; while the Red Pilots, under one of the most ridged and brutal of governments, could modify their aircraft.



Actually, I'd argue that the situation with regards to individual solider discipline was the reverse of this.

Despite the strong national emphasis on individual/personal freedom, the US military training and operational philiosphy was very much team oriented, with a command structure than was slightly more top heavy than the Soviet WW2 organisation. 

The individual US soldier had more scope for initiative, but he was probably also more disciplined than his Soviet counterpart, because the necessity of team-work and unit cohesion had been drilled into him in training. The US also had better basic command/control of its troops - most notable in air combat with radios - ensuring that commands could be understood and followed.

Despite the desotic and totalitarian nature of the Soviet regieme and the threats of punishment for transgressing rigid or even nonsensical orders, the average Soviet solider had notably less C&C and supervision over him in battle. With the command structure being so light (fewer NCOs and low-level commissioned officers), the Soviet soldier was probably required to act with just as much or more initiative than his US counterpart, despite ostensibly belonging to a more rigid military organisation.

While the independent/solo hero ignoring orders/showing personal initiative to win is enshrined in US WW2 folklore, I feel it was the team effort that the US excelled at in the war as much as any combatant in the period.

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## eWildcat (Apr 16, 2014)

As for the 37-mm cannon, interestingly enough a good number of the first P-39s used in combat by the USAAF were actually armed with a 20-mm cannon, as the P-400s used by the USAAF and the P-39D-1s amounted to a bit more than 450 aircraft (EDIT : After a more thorough check, the number of which that fought in the Pacific is difficult to accurately assess. It was significant, but much probably around 200 at best rather 450, as many aircraft were used either for training or in North Africa).


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## tomo pauk (Apr 16, 2014)

oldcrowcv63 said:


> This forum's resources may run deeper than you realize.



This looks like my new signature here.



> .... The Sho and Zui recovered 10 of these with 1 ditching at home plate. ...



Home plate  Fond memories on the Jane's 'Fleet command'.


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## oldcrowcv63 (Apr 16, 2014)

Fossil that I am, I had to look up Jane's 'Fleet Command.' '_Home Plate'_ is a real sobriquet for the carrier of an aircraft/aircrew's origin...


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## FLYBOYJ (Apr 16, 2014)

muscogeemike said:


> Yet that is what the Soviet’s did and had great success in the air to air role.
> It is weird to me that US Pilots, known for not adhering to discipline or orders they didn’t like, couldn’t or wouldn’t lighten their P-39’s; while the Red Pilots, under one of the most ridged and brutal of governments, could modify their aircraft.



I don't think you'll find that Soviet Pilots (more correct Soviet mechanics performing this for the pilots) modified their aircraft without some kind of approval first.


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## muscogeemike (Apr 16, 2014)

FLYBOYJ said:


> I don't think you'll find that Soviet Pilots (more correct Soviet mechanics performing this for the pilots) modified their aircraft without some kind of approval first.



OK, then explain why they, and again under their dictator, could be allowed to do this and not our own Pilots and Crews under a “free” government?
If they were free and this was a matter of survival why couldn’t they “shoot first and explain later”?


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## FLYBOYJ (Apr 16, 2014)

muscogeemike said:


> OK, then explain why they, and again under their dictator, could be allowed to do this and not our own Pilots and Crews under a “free” government?
> If they were free and this was a matter of survival why couldn’t they “shoot first and explain later”?



You're looking at this in a political light rather than the way an air arm is to operate. No one is saying they couldn't modify their aircraft, what is being said is PRIOR to any modification, a higher authority, usually an engineer, will validate, concur or disapprove a modification. You just don't go removing production items from aircraft; you have weight and balance as well as structural considerations to deal with. Mechanics (and especially pilots) do not come up with repair or modification schemes; that is the job of an engineer, the mechanic basically follows what the engineer tells him to do, this is commonly known as "approved data." Think of the engineer as preparing a recipe, think of the mechanic as a cook. That's not to say a mechainc or pilot may have an idea that an engineer could expand on.

In the end, this has nothing to do with governments or Commies; it has everything to do with accepted aircraft maintenance and modifications processes, during WW2 and even more so in today's world. Sometimes situations in the field may force some pretty wild modifications to be undertaken (some not only illegal, but very dangerous) but in the end no mechanic should be undertaking any kind of modification unless that mod has been analyzed and determined that there is nothing dangerous about it and it doesn't effect "form, fit or function," and most of the time mechanics AND PILOTS don’t have the education and/ or background to make that determination.


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## BiffF15 (Apr 16, 2014)

Hence the beauty of the "one time flight approval", to get her home!

Cheers,
Biff

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## muscogeemike (Apr 16, 2014)

OK, I accept your reasoning, FLYBOYJ, and I’m sure you know more than me. I’m not even a Pilot let alone a WWII Vet (although I have ridden some WWII era aircraft - including a P-38 ). (for some reason the post insist on putting a "smiley face" where I wrote P-38 )

It still seems strange to me. I spent 25 yrs in the Army, including VN. I know if in a combat situation, I wouldn’t hesitate to “alter” any piece of equipment with or without approval from anyone. If it would increase my survivalability or that of any of my men (or if it just made my life a little easier).

And I think removing the .30’s and ammo was easily doable and after a test flight would show no harm to the aircraft.

Our Pilots and ground staff were not dumbies and the thought must have come up at some time or another.


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## tomo pauk (Apr 16, 2014)

The point in Western fighters, compared with Soviet, is that the Soviets viewed those as having far more equipment on-board, when compared with their A/C. So there was more to cut from. Also, the Western fighters were notably bigger than Soviet ones, while not having that much more power, or more power at all. Bigger airframe - less a performer. So they cut on the guns, ammo, radios, armor. That was good for speed, and even better for RoC.


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## FLYBOYJ (Apr 16, 2014)

muscogeemike said:


> OK, I accept your reasoning, FLYBOYJ, and I’m sure you know more than me. I’m not even a Pilot let alone a WWII Vet (although I have ridden some WWII era aircraft - including a P-38 ).
> 
> It still seems strange to me. I spent 25 yrs in the Army, including VN. I know if in a combat situation, I wouldn’t hesitate to “alter” any piece of equipment with or without approval from anyone. If it would increase my survivalability or that of any of my men (or if it just made my life a little easier).
> 
> ...



No I hear ya Mike, but a little different with aircraft. Removing "ammo" wouldn't be a big deal since it is something considered "expended" during the mission (in many aircraft the CG would actually change with the ammo expended, the A-10 comes to mind), but now when you start to remove items that have no maintenance instructions for removal (guns, permantely mounted armor, etc.) that's where you need approval. I've included a P-39 weight and balance chart, you could see what's calculated in the W&B as well as the vertical and horizontal CGs.


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## muscogeemike (Apr 16, 2014)

Not to beat a dead horse but I'm pretty sure the guns were routinely removed for servicing and replacement. Things like armor and other equipment I can see not screwing around with.

And I have to believe someone thought of lightening the P-39, yet I've never seen any mention of it in anything I read.

I can't help but wonder why?


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## tyrodtom (Apr 16, 2014)

I do know that it was just a few minutes work to install the wing 20mm cannons in a AIE, because I've been close by installing bombs on one while the armorers were installing the wing guns. 
They took them out to clean and service after any mission in which they were fired.
The hardest part appeared to be for the man on the ground to lift them up to the wings.

And the armor I've seen was mounted so it could be replaced if it was ever struck. Because even if it wasn't penetrated, it still would be weak in that area thereafter.


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## GregP (Apr 16, 2014)

I can tell you that when you remove guns, you bolt in lead to compensate. For instance, we are currently restoring a Canadair Sabre Mk 6. It started life with three 50-cal MG in each side of the nose. Currently the weight of the gun in lead is bolted in at the correct spot to maintain CG. We also have some lead shot in the nose ring to help out, as we have lead shot in the wing leading edge of our P-51A to ballast the removed cannons.

So if the item to be removed is far from the CG and cannot be counter-balanced by removing SOMETHING from the other side of the CG, then it has to be ballasted. If it will be the same weight, why not just leave it there to start with? That's what we did when a friend bought a MiG-15 UTI. We cut the guns (actually the BATF did) and then re-welded them back together with the parts bolted in place, then removed them, finished the welding, ground it smooth, painted it black, and bolted it back in place.

Currently, I only know of ONE guy who has a P-51 with real wings guns in it. He cannot fly outside his own property with them installed.


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## BiffF15 (Apr 16, 2014)

GregP,

He must have some serious property...

Cheers,
Biff


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## GregP (Apr 16, 2014)

Uhhh ... yes ... he can fly an F-86 and never leave his own airspace.

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## FLYBOYJ (Apr 16, 2014)

GregP said:


> I can tell you that when you remove guns, you bolt in lead to compensate. For instance, we are currently restoring a Canadair Sabre Mk 6. It started life with three 50-cal MG in each side of the nose. Currently the weight of the gun in lead is bolted in at the correct spot to maintain CG. We also have some lead shot in the nose ring to help out, as we have lead shot in the wing leading edge of our P-51A to ballast the removed cannons.
> 
> So if the item to be removed is far from the CG and cannot be counter-balanced by removing SOMETHING from the other side of the CG, then it has to be ballasted. If it will be the same weight, why not just leave it there to start with? That's what we did when a friend bought a MiG-15 UTI. We cut the guns (actually the BATF did) and then re-welded them back together with the parts bolted in place, then removed them, finished the welding, ground it smooth, painted it black, and bolted it back in place.
> 
> Currently, I only know of ONE guy who has a P-51 with real wings guns in it. He cannot fly outside his own property with them installed.



Just about every jet warbird flying in civilian hands have ballast to make up for armament and in the case of east block aircraft, radios and nav equipment. Some of the Soviet radios I seen in L39s and MiGs I think weigh as much as lead!


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## gjs238 (Apr 16, 2014)

muscogeemike said:


> Not to beat a dead horse but I'm pretty sure the guns were routinely removed for servicing and replacement. Things like armor and other equipment I can see not screwing around with.<SNIP>



I think by "remove" he means permanently remove.


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## FLYBOYJ (Apr 16, 2014)

muscogeemike said:


> Not to beat a dead horse but I'm pretty sure the guns were routinely removed for servicing and replacement. Things like armor and other equipment I can see not screwing around with.


If it's within the aircraft maintenance manuals, absolutely. In the tech section there is a P-39 armament manual that describes servicing and routine maintenance .


muscogeemike said:


> And I have to believe someone thought of lightening the P-39, yet I've never seen any mention of it in anything I read.
> 
> I can't help but wonder why?



A few thoughts...

Without removing vital factory equipment or risking structural failure, there might have been limitations in trying to make it any lighter than the Soviets did. Additionally Bell was already developing the P-63, so I don't think the interest was there.


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## tyrodtom (Apr 16, 2014)

I realize removing the guns of a F-86, or Mig-15, is going to have a pretty big effect on the CG.

But the wing guns, and ammo on most WW2 aircraft are pretty close to the CG, you might be able to remove them and get the CG back into limits with some fairly light weights further from the CG. Am I wrong ?


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## GregP (Apr 16, 2014)

We had lead shot in the leading edges of our P-51A.

Of course, they were cannons with heavy breeches. I don;t believe we have any lead in the P-51D's, but am not really sure. I will check!


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## Shortround6 (Apr 21, 2014)

Somethings to consider when comparing the P-39 (several different models), P-40s (also several different models) in combat vs Japanese fighters ( also several different models), is different tactical situations.

In Regards to the AVG they were fighting the Japanese Army with Ki 43 and some Ki 27s for fighters. The majority of the Ki 43s had one 12.7mm and one 7.7mm machine gun and had much less firepower than the Navy Zeros, at least for the first 6-8 seconds. 
Some of the AVG tactics involved only fighting when they had an advantage, preserving their own aircraft was a a _very_ important consideration. This is something that may not have been a high priority in other areas, (perhaps it should have been?) 
Japanese Army cooperated by flying strikes at altitudes the P-40s could operate at and/or the AVG had more advanced warning than some the South Pacific bases. 
Germans co-operated with the Russians flying P-39s by NOT flying bombers at 23-28,000ft like the Japanese Navy often did in the SP. 

You also have the climate differences. A lot of the "book" figures for aircraft performance are done at standard temperature and pressure (usually 59-60 degrees F or 15 degrees C for temp) and performance falls off with increasing temperatures. Higher air temps mean lower air density and both less lift from the wing and less engine power. Throw in less the perfect aircraft condition (it is one thing to change spark plugs when suffering from Dysentery and Malaria, it is another thing to wash and wax the aircraft) and aircraft in tropical conditions maybe operating at less than "book" figures. Less lift means a higher stalling speed even in a 2 "G" turn and more power needed to maintain minimum flying speed. 
It can get hot in Russia but not _tropical_ hot for weeks/months on end. 

Please also remember that _average_ combat height is exactly that, an average. One fight at 5,000ft, one at 10,000ft, one at 20,000ft and one at 25,000ft _average_ 15,000ft. However if you are flying P-39s you are at a distinct disadvantage in two of those fights.


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## buffnut453 (Apr 21, 2014)

Shortround6 said:


> Some of the AVG tactics involved only fighting when they had an advantage, preserving their own aircraft was a a _very_ important consideration. This is something that may not have been a high priority in other areas, (perhaps it should have been?)



Sometimes it's impossible to manage the fight to ensure you only fight on advantageous terms. Lack of early warning often means having to respond when the attacks come which can result in engaging at a tactical disadvantage. The alternative of having fighters constantly airborne is only practical if you have sufficient aircraft available - standing patrols are notoriously costly from the maintenance and availability perspectives.


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## varsity07840 (Apr 21, 2014)

I'm always amused at how these woulda, coulda, shoulda threads, especially about the P-39 and P-40 vs the Zero eventually go off on a tangent, probably becasue there's not much left to say. Having said that, I'll through in my two cents worth. The P-39 was a fighter designed around a gun, not a fighter with a gun designed for it. As such it was doomed to be a pre-war design to pre war standards with no growth potential save perhaps the use of the 2 stage engine used in the P-63, which suffered from the same range limitations, poor armament/design philosophy. It was not a Zero killer or even a potential Zero killer. It was Zero food.

Duane


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## FLYBOYJ (Apr 21, 2014)

varsity07840 said:


> I'm always amused at how these woulda, coulda, shoulda threads, especially about the P-39 and P-40 vs the Zero eventually go off on a tangent, probably becasue there's not much left to say. Having said that, I'll through in my two cents worth. The P-39 was a fighter designed around a gun, not a fighter with a gun designed for it. As such it was doomed to be a pre-war design to pre war standards with no growth potential save perhaps the use of the 2 stage engine used in the P-63, which suffered from the same range limitations, poor armament/design philosophy. It was not a Zero killer or even a potential Zero killer. It was Zero food.
> 
> Duane



Duane;

While I cannot disagree with anything you say, there's a broader picture here that is continually danced around. I could bring the same old rant about "How come the Soviets did so well with the P-39," but I think we already know the P-39 was at its' best element where the Soviets were operating it (at low level, close to home), but despite being "Zero Food" it seems the units operating the aircraft just soiled on and I think we have found that although the P-39 was shot down in numbers perhaps 3 fold in what they dished out, it was the Japanese who suffered the high pilot attrition rate that eventually led to a loss of air superiority over the Solomons, this happening during the final days of the P-39 in that region. It would be an amazing task (but all ready recognized as virtually impossible) if we could really determine how well (but in reality how lousy) the P-39 REALLY did against the Zero. Folklore leads us to believe that this aircraft was swept from the skies and all who flew her eventually became shark food, but the P-39 did enable some outstanding fighter pilots to gain combat experience and live to tell about it (Tommy Lynch for one). 

I'm not trying to re-write history or paint a better picture of this aircraft than what it's combat record actually reveals, but I think we should look at the P-39 experience as using "the wrong tool for the wrong job" unfortunately at the time no one in the AAF wanted to admit to that even though I think they knew the limitations of this aircraft. It was all that was available and like the grunts on the ground using their 1910 Enfields, AAF pilots had to go with the P-39 (or P-400).

Even at an actual 1:3 kill ratio (if you want to believe the most extreme numbers) this "dog" of an aircraft did succeed in at least holding the line at places like Henderson until late 1942 when the real game changer entered the fray, and at that point I think the Zero (and other Japanese aircraft) became a common snack.


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## tomo pauk (Apr 21, 2014)

The Zero wasn't ideal fighter itself, and the growth potential was limited there, too. 
The location of fuel tanks (in the wings) was similar to the P-39. In case one wants to have those in self-sealing variety, it will have to pay the price, exactly as the P-39 did - serious degradation of fuel tankage, along with weight increase. The XP-39 started with 200 US gals, decreased to 170 gals from YP-39, and further down to 120 gals when P-39C was superseded with P-39D, due to introduction of s-s tanks.
The Zero have had around 150 US gals, and never received s-s tanks; how much had they bother to install them - 100-110? Even the Oscar introduced them, mid-war. Zero was a better climber, especially above 15000 ft, the P-39 was better protected. P-39 rolled better as speed went up, the Zero rolled better at lower speeds.
The fastest Zero was making 350+ mph, the fastest P-39(-Q) was at 380+ mph, and a 390+ without external guns. I'm not sure that USAF ever used those against Zeroes. Installation of the belt-fed 20mm in P-39 should be a trivial exercise.


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## Shortround6 (Apr 21, 2014)

The P-39 did help "hold the line" in the South Pacific but it seems more like a situation in which the Allies could _afford_ to loose P-39s/P-40s (and some pilots) while delaying/stopping the Japanese and the Japanese could NOT afford to loose the planes and more importantly, the pilots, they were loosing fighting the P-39s and P-40s. It might have been very hard for the Allies to over to the offensive using P-39s and P-40s though without a much longer and costlier battle of attrition. The P-39/P-40 offered a higher survival rate for the pilots if operated close to home bases, too.


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## gjs238 (Apr 21, 2014)

In Guadalcanal would the P-40 have performed any better than the P-39?


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## GregP (Apr 21, 2014)

I looked at our P-51A. There are plugs in the cannon holes, but they are wood plugs, not lead. So the CG change MUST be minor for the wing cannons. We MAY have also moved some items in the fuselage to restore CG of which I am not aware.

Interesting aside, our P-51A is the only flyable one in the world at this time as far as I am aware ... and it has been "down" for about 3 - 4 years since the last time we flew it. It has been a source of great trouble and it all centers around the radiator. They finally "had enough" and designed a new radiator from scratch, actually radiator /oil cooler, and have installed it in the plane. Last Saturday, we pulled it out for a first engine run since the last flight.

After sitting for 3 - 4 years, John Hinton turned the Allison over 3-blades and it fired right off and ran smoothly. Looks like it will be flying again for our airshow in 2 weeks (May 3 - 4)! 

Glad to see it flying again.

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## RpR (Apr 21, 2014)

varsity07840 said:


> As such it was doomed to be a pre-war design to pre war standards with no growth potential save perhaps the use of the 2 stage engine used in the P-63, which suffered from the same range limitations, poor armament/design philosophy. It was not a Zero killer or even a potential Zero killer. It was Zero food.
> 
> Duane


That statement is just a bit obtuse.
The P-51 was a pre-war design also.

Had the Germans in WW II not had the bomber to deal with and went exclusively after the fighters, the kill ratio in Western Europe would probably be a lot different.
The P-39 pilots had to attack bombers first and fighters second, there is a big difference between that and escorting bombers where the pilots can put full effort into destroying the fighters.
On the Eastern front the German pilots did not have massive flights of bombers to deal with the kill ratio shows it.

If you read the story that goes along with much of the P-39 action the pilots are saying they were attacking bombers and defending against being attacked by fighters.

The fact the P-39 shot down as many enemy fighters as it did, despite being crippled by asinine military specs. it had to deal with, makes the Zero food statement rather asinine.


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## FLYBOYJ (Apr 21, 2014)

Gentlemen, keep this civil please!


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## Garyt (Apr 21, 2014)

> The P-39 did help "hold the line" in the South Pacific but it seems more like a situation in which the Allies could afford to loose P-39s/P-40s (and some pilots) while delaying/stopping the Japanese and the Japanese could NOT afford to loose the planes and more importantly, the pilots, they were loosing fighting the P-39s and P-40s. It might have been very hard for the Allies to over to the offensive using P-39s and P-40s though without a much longer and costlier battle of attrition.



This is an important point that colored the whole war. The US was in far better shape to handle attrition in regards to pilots. The US could handle attrition in aircraft better as well, but the key is pilots. It's funny, Japan was ill suited to replace it's pilots as well as the US - but also had the planes that were the worst for pilot survival.

Guadacanal was actually wonderful for the US war efforts. It was a slow attrition based mini-theatre, in men, materials and machines.

A decisive Naval battle played less into the US hands, it would be less of an attrition based battle. We were fortunate to have won Midway, but a decisive Naval loss would be harder to come back from. Not that the US could not with its manufacturing base - it's just that it takes longer to replace large warships than it does to replace planes and materials.


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## varsity07840 (Apr 22, 2014)

BobR said:


> That statement is just a bit obtuse.
> The P-51 was a pre-war design also.
> 
> Had the Germans in WW II not had the bomber to deal with and went exclusively after the fighters, the kill ratio in Western Europe would probably be a lot different.
> ...



You seem to like the "A" word. The P-39 was a PREWAR design based on a spec issued of 1937. It's first flight was
in 1938, over a year BEFORE war broke out. The P-51, with an advanced airframe and airfoil was designed in 1940, AFTER the war broke out. Take the emotion out of the evaluation. The P-39 was a poor performer over 12,000 feet as acknowledged by countless piolts that flew it. It had a lower performance at atitude than the bombers it was tasked with 
intercepting and were sitting ducks for escorts that were always above them. 

I hope that's civil enough.

Duane


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## Shortround6 (Apr 22, 2014)

The US seemed to have a real tendency to over-gun it's fighter planes. I have no idea if this was a result of actual firing tests or "fly by the seat of the pants" specification. This was compounded by the weight not only of the .50 cal gun but the weight of .50 cal ammunition. The P-39 was doubly unfortunate because the US seemed to want the armament of two fighters crammed into one. If all the ammo bins were full it carried 3 times the weight of guns and ammo that an early Zero did and in fact carried a greater weight of guns and ammo than a Hawker Typhoon with four 20mm cannon. A lot to ask of 1150hp in the early models. Unfortunately this also results in structural weight that cannot be easily taken out. The plane is 'stressed' to a service load of 8 'G' s and an ultimate load (safety factor) of 12 'G's. You need a heavier structure to hold the heavier weight of armament ( and the armor and the self sealing tanks) and the structure remains even if you pull some of the guns and fuel tanks out. 
This over gunning was built into the specifications of a number of the early war prototype fighters. P-46 had two .50s and eight .30s on 1150hp. P-53 had eight .50s on either a 1600hp IV-1430 or a R-R Merlin. XP-60 continued the eight gun set up but guns were dropped as performance estimates plummeted. 

The P-39 was not helped when the Prototype (without guns) came in about 10% over weight. With the armament fit and protection an _empty equipped_ P-39 weighed only a few hundred pounds less than a Spitfire V with full ammo and full internal tanks.


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## Denniss (Apr 22, 2014)

Was the P-400 any better than the P-39? It should weight less due to the 2cm gun instead of the 3.7.


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## Shortround6 (Apr 22, 2014)

A bit better but only by about 100lbs or so and since that is out of around 7500-7600lbs ( after a bit of fuel burn off) it shouldn't make a whole lot of difference. The plane was lugging around 260lbs worth of .30 cal ammo (1000rpg) so cutting the .30 cal ammo to 500rpg would 120-130lbs and still leave 25 seconds of firing time.


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## tomo pauk (Apr 22, 2014)

Looking at performance tests at Williams' site, it does not seem that a lighter cannon offers any appreciable advantage for both speed and climb.


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