The P-39 a Zero Killer???

[oldcrowcv63]

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?

 

[meatloaf109]

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.

 

[parsifal]

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)".

 

[GregP]

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.

 

[Juha]

...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).

 

[Wildcat]

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.

 

[buffnut453]

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

 

[oldcrowcv63]

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.

 

[oldcrowcv63]

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?".

 

[varsity07840]

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

 

[parsifal]

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.

You lucky sob. Im jealous as hell

 

[vikingBerserker]

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.

 

[FLYBOYJ]

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".

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.

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.

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.

 

[gjs238]

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

 

[varsity07840]

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

 

[GregP]

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.

 

[FLYBOYJ]

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.

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

 

[tomo pauk]

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

 

[oldcrowcv63]

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

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.

 

[GregP]

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.