Do we have any encounters of P51s with A6Ms?

[BiffF15]

could it have been strict flight discipline...not breaking formation to take a pot shot...or was it over confidence that they had overwhelming odds??

BobbySocks,

If the odds were 15 to 1 in an ally knife fight, I would be confident of winning it HOWEVER I would respect the singletons knife. Also, in this case it was a narrow ally and only 1-2 guys at a time could take a run at him.

As for flight discipline they succeeded in not hitting each other (rule number one being don't hit the ground, or anything that will take off or land on said ground, or anything attached to it), they succeeded in rule number two, maintain the offensive, however they came up short on the effective employment of weapons objective. I read the book but it's been many years ago, however IIRC the Hellcats kept attempting the same tactic repeatedly with the same (non-successful) results.

Many moons ago I fought a F-18F Super Hornet with no external stores (drag devices) in a F-15A with two external wing tanks. We accomplished two fights and I cleaned his clock on both due to his tactics. In the debrief I asked him why he did what he did to which he replied it was USN Tactics right out of their book. Then I asked him the clencher, "Your tactics didn't work today, if you went out tomorrow what would you do different?" I'm hoping the Hellcat guys asked the same question in their debrief...

Cheers,
Biff

 

[VBF-13]

Sakai was a great pilot and knew how to place his aircraft at an advantage, he also knew when to run when he can. It was all about tactics. Had CW Spit pilots used the right tactics, they should have been able to cut the Zero to ribbons.

Bottom line, the Zero, be it flown by Sakai or a rookie was not going to do well in a traditional dogfight at speeds close to Vmax. One also has to factor in the element of surprise and tactical advantage as shown in my earlier post.

This is in a footnote in Wikipedia on the F6F:

"On the previous day, while receiving the Congressional Medal of Honor from President Franklin D. Roosevelt, O'Hare was asked by the President what was needed in a new naval fighter; O'Hare's response was "something that would go upstairs faster."[15]"

15. Ewing and Lundstrom 2004, pp. 155–156.

 

[Balljoint]

This does not explain how Sakai could go against 15 hellcats with no support and survive without a scratch.

Pilot skill, pilot skill, pilot skill. One on one and with an initial advantage over Pug Southerland, in a Wildcat no more, Sakai suffered a reversal and would have been cashiered but for jammed guns on the Grumman.

It's also a bit unfair to compare a fighter in the interceptor mode, i.e. avid the escort and get to the bomber, with heads up combat between fighters, it would seem.

 

[FLYBOYJ]

This is in a footnote in Wikipedia on the F6F:

"On the previous day, while receiving the Congressional Medal of Honor from President Franklin D. Roosevelt, O'Hare was asked by the President what was needed in a new naval fighter; O'Hare's response was "something that would go upstairs faster."[15]"
Ewing and Lundstrom 2004, pp. 155–156.

O'Hare received the MOH on April 21, 1942. The first F6F flew June 1942 and the first deliveries were made in January 1943. I think someone else also had the same feelings.

 

[VBF-13]

O'Hare received the MOH on April 21, 1942. The first F6F flew June 1942 and the first deliveries were made in January 1943. I think someone else also had the same feelings.

They all knew it.

 

[Shortround6]

One of the things better fighters do is allow green pilots a better chance (but by no means 100% guarantee) to gain experience. They may allow green pilots to inflict more damage on the enemy for the same amount of losses.

A lot of WW II air combat over long periods of time (months long campaigns) came down to averages and statistical probabilities. Loss rated per 1000 missions and "victories" ( or bombs dropped) per 1000 missions.
Better aircraft could 'tip' the balance a bit but not guarantee total dominance without a number of other factors. On the other hand using inferior aircraft while having a number of advantages may very well work but at a large cost.

While the thirsty American planes needed more fuel brought to them and the Better trained American pilots used up more fuel and and aircraft (crashes) in training every American fighter had to brought into the theater by ship. Replacement pilots could be flown in by air transport ( but even trans-pacific air transport seats were limited). Trying to overwhelm an enemy with larger numbers of inferior planes also means more ground crewmen and support personnel ( and neither carriers nor most Pacific Island can grow enough food to feed the occupying air forces). The US may have had enough men and shipping to pull off a win using poorer planes but having better ones made things a lot easier.

IF the better planes needed 10-15% fewer aircraft to get the same results or needed 10-15% fewer replacements in a six month period that can be an advantage that does not show up in simple kill/loss ratios.

And how many hours/mission/engagements does it take to go from "green" (even if well trained) to "experienced" pilot? Even in the BoB not every flight ( or even every 3rd flight) resulted in an air combat but in the Pacific a number of hours on every flight could be spent just flying over water with little or no chance of engagement.

Not all pilots even with the same number of hours of training are equal combat pilots. Leaving out the 'aces' better planes allow a better percentage of the "green" pilots a chance to either make a difference or to survive until they get enough experience to make a difference. And some, due entirely to luck and statistical chance, can fly dozens of missions and never get an enemy plane in their gun sight. They all can be lost due to mechanical failure, weather change (head wind and run out of gas) or other accident regardless of plane used.

 

[parsifal]

Pilot skill, pilot skill, pilot skill. One on one and with an initial advantage over Pug Southerland, in a Wildcat no more, Sakai suffered a reversal and would have been cashiered but for jammed guns on the Grumman.

This was certainly southerlands day, he shot down two G4Ms I believe, before being engaged by at least 3 Zekes, not including Sakai. Sakai in his memoirs claims that he thought Southerland was attacking Sakai s comrades (including his wingman), however i personally find that hard to accept. i think it more likely he observed the fight, realized his guys were getting nowhere shooting the US pilot down, also realized the US pilot was not firing even though he was given several opportunities to do so, and decided to exploit that by finishing him off quickly. I think, but cannot prove, that sakai was prepred to take risks to bring down this lone pesky American, hence his mistake of allowing his plane to be in the firing line.

I also dont accept Southerlands account in its entirety. after the war, Southerland claimed all he was trying to do was get back to the American "Red Beach" area so that he could bail. And yet, other accounts have him frantically either attempting to unjam his guns, or reload them . Why would you do that if you are intending to run? I think both men are embellishing their stories. i think Sakai was intending to kill an American whom he observed was not firing, and i think Southerland was running, he was also trying to get nback into the fight.

Saying also that it was a "wildcat, no more" is also misleading. Wilkdcat it was, yet these same aircraft, along with P-29s, P-40s and Fother mid war aircraft had by June 1943 detroyed 6500 Japanese aircraft and torn the heart out of the Japanese war machine. they had, effectively, won the war, and continued to make significant contribution to the Allied war efforts well into 1944.

Saying it was all about pilot skill is also misleading. of course pilot skill was very important, crucial, in fact, but if the zeke was hopeless, it would not matter how good its pilot was. Good pilots can only do so much. it was in fact (in the overall sense) a question of pilot skill, tactics, logistical support and numbers that won the air war in the Pacific. Any other permutation from that, that tries to say it was just this, or just that is an absolute, that clearly defies the historical truths.

It's also a bit unfair to compare a fighter in the interceptor mode, i.e. avid the escort and get to the bomber, with heads up combat between fighters, it would seem

.

Maybe, but during its career, the zeke was called upon to do both, and in both roles had its sucesses and its failures. over Darwin, it was operating offensively, and essentially won. over Iwo it was operating defensively, and whilst not winning, did come out the clear winner/survivor. if the aircraft was so deficient, it could not have won in either case, despite the "other factors" at work in each case.

 

[parsifal]

And how many hours/mission/engagements does it take to go from "green" (even if well trained) to "experienced" pilot? Even in the BoB not every flight ( or even every 3rd flight) resulted in an air combat but in the Pacific a number of hours on every flight could be spent just flying over water with little or no chance of engagement

Very good post SR, in relation to the above extract, it rather depends on the quality of your opposition

At the beginning of the PW, average flying hours for the Japanese pilots on the carriers was in excess of 700 hours. Thats combat hours incidentally, not training times. At that time Japanese pilots were training for about 400 hours to get their carrier wings, so these guys probably had about 1200 hours flying time. It was reflected in a number of ways, including the bombing accuracy. over the Dorsetshire and Cornwall, the D3As were achieving about 80% hit rates against a seagoing target. nobody could match that.

by 1945, there were virtually no carrier trained pilots left. at Phil Sea, the Japanese Carrier pilots left had averages of 150, 100 and 50 hours, depending on which cardiv you want to look at. by the second day, the Mob fleet was down to less than 50 planes left, but of these, there were high numbers of very experienced aircrew....the last of the best. When called upon to fight the US carrier air strikes that evening, these guys in the alleged obsolete zekes, did very well, though outnumbered by at least 6:1. A strike in excess of 200 bomber aircraft, escorted by swarms of F6Fs did manage to sink the Hiyo. If the defending CAP was not up to it, they should have wiped out the Mob fleet. They failed in that.

Against the rookies that made up the majority of the japanese FAA at that time, the average flight time of the USN was about 500 hours, including their training. These US guys easily got the better of those IJN rookies, tearing them out of the sky. i have often woncered how these guys, in hellcats, might have fared against the Combined fleet in 1941, when the Japanese were at the peak of their game. Thats what the victory at midway can lay claim to being the most amazing victory , and Phil sea, to me, is just another garden variety massacre.

 

[VBF-13]

At the beginning of the PW, average flying hours for the Japanese pilots on the carriers was in excess of 700 hours. Thats combat hours incidentally, not training times. At that time Japanese pilots were training for about 400 hours to get their carrier wings, so these guys probably had about 1200 hours flying time. It was reflected in a number of ways, including the bombing accuracy. over the Dorsetshire and Cornwall, the D3As were achieving about 80% hit rates against a seagoing target. nobody could match that.

by 1945, there were virtually no carrier trained pilots left. at Phil Sea, the Japanese Carrier pilots left had averages of 150, 100 and 50 hours, depending on which cardiv you want to look at. by the second day, the Mob fleet was down to less than 50 planes left, but of these, there were high numbers of very experienced aircrew....the last of the best. When called upon to fight the US carrier air strikes that evening, these guys in the alleged obsolete zekes, did very well, though outnumbered by at least 6:1. A strike in excess of 200 bomber aircraft, escorted by swarms of F6Fs did manage to sink the Hiyo. If the defending CAP was not up to it, they should have wiped out the Mob fleet. They failed in that.

Against the rookies that made up the majority of the japanese FAA at that time, the average flight time of the USN was about 500 hours, including their training. These US guys easily got the better of those IJN rookies, tearing them out of the sky. i have often woncered how these guys, in hellcats, might have fared against the Combined fleet in 1941, when the Japanese were at the peak of their game. Thats what the victory at midway can lay claim to being the most amazing victory, and Phil sea, to me, is just another garden variety massacre.

OK, what do you say we get this thread back on track? I believe we covered this ground, before. I'll tell you what, if you hadn't had enough, start a new thread on this digression you're taking, and we'll go over it, all, again, I really don't mind. Just don't name it, "Do we have any encounters of P51s with A6Ms?," as that might be a tad misleading.

 

[parsifal]

we are on track. The supposition you make is that the zeke was obsolete, and had no chance against a mustang is the the broken bit of this discussion. There are problems with the starting supposition that you cant resolve. Thats because your starting point is cracked and broken, not that we are off topic. The only thing off topic is that we are talking Hellcat and Zero, not p-51 and zero. nuuman posted a report on the allison powered p-51 versus the zeke. im not aware of any merlion powered mustang comparison, but I am aware of merlin powered spit comparison to the zeke. The spit comparison shows the spit to be superior, but the zeke was not totally outclassed.

what defeated the zeke, wasnt just that it was moving towards obsolescence. It was defeated by a whole range of factors. im not denying that it was pasted toward the end, but I am challenging that this was all to do with the deficiencies of the aircraft. Japans (and the zeros) defeat was far more comprehensive than that.

Technology, be it a hellcat, a zero, or a mustang is but one factor in the victory equation, and guess what, its a relatively minor factor. Far more important are numbers, the manpower and the supply situation. Tactics and strategy are also big factors.

If you want to get this back on topic, get the question right first.

 

[eagledad]

Greetings parsifal,

For comparison between the P-51D and the A6M5, please see the file found at:

http://www.wwiiaircraftperformance.org/japan/zeke52-taic38.pdf

Mike Williams and Neil Stirling fine web site.

Eagledad

 

[parsifal]

Thankyou, very much apreciated. it confirms what has already been said....Zeke has the turning advantage up to 250mph against most, is slightly better up to about 280mph, and then falls away sharply from that point on. Generally has the roll rate advantage up to 280mph as well. in dive, level speed and high speed climb, is at a disadvantage. not shown is that at low level its rate of climb was closer to being competitive.

Smart Zeke pilots when confronted with boom and zoom tactics , such as Sakai, would generally use a half roll and flick turnat the last moment . it needed nerves of steel, some dumb luck and precise timing to pull it off, but could generally work, if the pilot had the skill to do it. problem was, at the end of the war, skilled pilots in the IJN were virtually non-existent.

Zeke was armed for a close in turning fight. if it could get you in its sights and pump even a few of its 20mm (and in the case of the later Zekes, it HMGs as well) it could pretty much open any US fighter up like a can opener. Problem was, getting the opportunity to make that burst. they seldom got the opportunity later in the war. And that was a product of the war as a whole. most Zekes were simply shot up on the deck, or were flown by sheer cannon fodder.

but obsolete it aint, as the report clearly shows. It simply had the wrong atributes for the pilots and the numbers at the dispposal of the IJN at the end. Its lack of armour and flame suppression was another glaring weakness

 

[Shortround6]

The thing is that this comparison uses the A6M5 which is probably the best performing Zero fighter (even if this example may not having been performing up to par). From the A6M5a,b, c and on the plane increased weight by adding armament ( or just better ammo feeds), protection and heavier wing skinning without gaining much more (if any) power, hopes were high for the water injected version of the Sakae engine but apparently it didn't live up to expectations. So while the better armament and protection should
have held off obsolescence a bit longer the slower and slower climbing models may have found it even harder to get their guns on target, or to evade being targets. (adding two 13.2 MG in the wings with just 200rpg each is around 250lbs of added weight, may be over 300lbs with mounts ammo boxes, heaters,etc)

The Zero, as a design, may have had life left in it (A6M8 ?) but the failure to increase power after 1943 to any appreciable extent rather doomed the service models and the what remained of the JNAF. Being able to avoid being shot down by better enemy fighters given a decent pilot (not great) and favorable circumstances is not really disputing control of the air. It is not protecting your own bombers/torpedo planes the way they need to be protected to do their jobs and it is not shooting down the enemy bombers/torpedo planes in the way that is needed to safe guard your own fleet.

I am not talking about 100% shoot downs, just enough to tip things a bit.

 

[VBF-13]

I think I hear you saying that without more horsepower these improvements weighting them down actually disadvantaged them. Were the P51s that much more powerful under the hood? I know they were twice as heavy, give or take a little.

 

[Shortround6]

They added firepower and protection in the later models but the engine stayed pretty much at 1130hp for take-off, 1100hp at 2850 meters( 9,350ft) and 980hp at 6000 meters ( 19,685 ft), the water injection system didn't seem to do what was hoped for according to most accounts ( they could be wrong?) and the Mustang was nowhere near twice as heavy in combat mode, Max take-off is different. The P-51 max take-off weight include a pair of 1000lb bombs or some really big drop tanks. Combat weight of a P-51 is going to be somewhere between 9000 and 10,000lbs depending on how much fuel in in the internal tanks. A P-51D went about 9643lbs with racks and full internal fuel (1080lbs of fuel) without rear tank. With rear tank it went 10208lbs with 1590lbs of fuel. Internal fuel (but not rear tank) was used for starting, warm up, initial take-off and climb out and rear tank was burned down to a certain percentage before drop tanks were used normally.
Even a A6M3 was NOT a 5000lb machine even with the "drop" tank empty or gone.

 

[VBF-13]

I didn't understand what I read on the weights, then. OK, give the A6M5 the bigger engine. Does that do the trick? Is that where that fighter needed to go to remain competitive?

 

[tomo pauk]

The Zero was bigger than, say, Fw-190. It was aproximately as big as Ki-84. So I'd say that, for the Zero to remain competitive beyond 1943, it will need the Ha-41, Ha-109, or Ha-45 installed. Ha-41 and 109 were installed in Ki-44 Shoki, Ha-45 is the renown Homare.

 

[Shortround6]

I didn't understand what I read on the weights, then. OK, give the A6M5 the bigger engine. Does that do the trick? Is that where that fighter needed to go to remain competitive?

Yes but they waited too long.

A A6M5c was about 600lbs heavier than a A6M5 due to the guns, ammo, armor and protected fuel tanks. On a Zero that is about 10%. Due to weight and drag it was about 13kts slower. No figures on climb but adding 500lbs to a P-39Q could knock about 500fpm off it's climb.

In late 1944 the Navy finally gave permission to fit the Kinsei engine to the Zero and 2 prototypes (A6M8 )were finished in the summer of 1945. 1560hp for take-off, 1340hp at 2100 meters (6890ft) and 1180hp at 5800 meters ( 19,030ft). Pretty much the same engine used the Ki 100.

 

[Shortround6]

The Zero was bigger than, say, Fw-190. It was aproximately as big as Ki-84. So I'd say that, for the Zero to remain competitive beyond 1943, it will need the Ha-41, Ha-109, or Ha-45 installed. Ha-41 and 109 were installed in Ki-44 Shoki, Ha-45 is the renown Homare.

You might need a whole new plane for those engines. Just fitting the Ha-112 ( Kinsei 62) required deleting the cowl gun/s.

The Ha-41 was the earliest but used a single speed supercharger. the Ha-109 was probably the best bet after the Kinsei engine. It was only 4 in (110mm) bigger in diameter than the Sakae and 130 kg heavier than a Sakae 21 (which was 60kg heavier than a Sakae 11/12) and the Zero had been originally designed around the Mitsubishi Zuisei engine which was slightly smaller and lighter than the Sakae.

Problem for the Japanese was ANY engine change would cut into the range/radius of the Zero. Could a bigger engine allow enough fuel to make up for the increased consumption? A number of Zeros were lost when they changed form the Sakae 11/12 to the 21 due to smaller fuselage tank and increase fuel consumption.

Once the Japanese are on the defense it doesn't matter quite as much.

 

[parsifal]

Japan had desperately sought major qualitative improvements in the A6M4. A6M3 had appeared before the end of the guadacanal campaign, and the Japanese deluded themselves into thinking it could solve the ever increasing superiority held by the Allies. The model 32 itself was delayed by Mitsubishis divided attentions between the J2M, the Zeke and the A7M. Design work on a replacement for the A6M2 began well before Midway, but the A6M3 was a watered down interpretartion of that new mark.

The a^M3 was meant to be a lightweight version of the J2M, and the J2M aimed to boost speed, climb firepower, dive and protection to the same level as allied fighters, whilst retaining the unmatched horizontal manouverability of most Japanese aircraft. The A6M3 incorporated some changes to boost zeke capabiliies, but really, fell short of the mark. the main differences was a switch to belt fed cannons, with ammunition increased from 60 to 105 rounds per gun. Ammunition counters were also fitted, and the radio installatioon improved. Engine power was significantly increased, to 1130hp, with a two stage blower also fitted. great things were expected in the performce increases arising from this new engine, but the increase in performance was really very modest. Top speed of the model 32 was 345mph @ 20K ft, an increase of 14mph over the A6M2, and slightly more over the model 11. The Model 32 was slightly less manouverable, with a smaller wing area, and slight increase in weight, and it was the model 32 that initially faced up to the hellcat. There were compensations for this however. Mitsubishis nearly doubled the number of skin fasterners in the wing, and the wing skins were increased in thickness. this increased sustained dive speed to over 410 mph, which was still a lot less than its American counterparts, but significantly better than the old model 21. Roll rate was superior to the hellcat, its chief adversary.

in one aspect, the model 32 was inferior to thge model 21. The larger engine fit and supercharger increased fuel consumption, and also necessitate3d shifting the firewall 8in back which further reduced fuel capacity. This of course affected its effective range, though in this area it remained superior to the hellcat. However the P-51 easily outclassed it. The model 32 had 24% less range compared to the Model 21. At a range of 650 miles, its typical operating range in the Solomons, it had just over an hours endurance over the target. Often model 32s operating over Guadacanal or goergia carried two 45 liter drop tanks under the wings.

The Jpanese did not produce the fighter they needed in late 1942 until late 1944, and by then it was far too late. After the a6M, as suggested above they had intended to improve Zero performance in a major way with the A6M4

Full details of the A6M4 are still not known, even today, but very recently, acclaimed aviation historian Jim Long has discovered some translated Japanese documentation that supports the turbosupercharger theory by referencing an intercooler, a device commonly used with a turbocharger that works like a radiator to cool hot compressed air. However, as he points out, it's not a lock, and questions remain as to the layout.

Tracking down the A6M4 is frustrating, elusive and often contradictory

Here are some comments thaqt i am aware of

The Mitsubishi A6m3 Zero-Sen ("Hamp"), by René J. Francillon, Aircraft In Profile No. 190 , ©1967

"THE TURBO-SUPERCHARGED SAKAE

"The A6M4 version of the Reisen has long been conspicuously missing from the various historical studies yet published on this aircraft and even the designer of the Reisen, Mr. Jiro Horikoshi, could not remember what the A6M4 was! However, Mr. Horikoshi had the kindness to inquire among his friends of the former Imperial Japanese Navy and, recently, was able to confirm to the present writer that the A6M4 designation was applied to two A6M2s fitted with an experimental turbo-supercharged Sakae engine. The design, modification and testing of these two prototypes was the responsibility of the Dai-Ichi Kaigun Gijitshusho (First Naval Air Technical Arsenal) at Yokosuka and took place in 1943. Lack of suitable alloys for use in the manufacture of the turbo-supercharger and its related ducting resulted in poor operation marred by numerous ruptures of the ducting, and fires. Consequently further development of the A6M4 was cancelled, the aircraft still providing useful data for further aircraft, and the manufacture of the more conventional A6M5, already under development by Mitsubishi Jukogyo K.K. was accelerated."

Japanese Aircraft of the Pacific War, by René J. Francillon, Naval Institute Press, ISBN 0-87021-313-X, ©1970. Pages 369-371 have a couple of paragraphs that say:

"In Japan at that time Mitsubishi and the Navy were attempting to improve the Reisen. At low altitude it could still hold its own against Allied aircraft, but at medium and high altitude it was hopelessly outclassed by the Lightnings and Corsairs. In an attempt to correct this situation two A6M2s were modified by Dai-Ichi Kaigun Koku Gijitsusho at Yokosuka and, designated A6M4s, were powered by an experimental turbosupercharged Sakae engine. Major teething troubles with the experimental engine precluded the placing of a production order and the Navy had to settle for an interim version of the aircraft, the A6M5, pending availability of the new Mitsubishi A7M Reppu... To improve diving speed Mitsubishi modified the 904th A6M3 in August 1943 by fitting a new set of wings with heavier gauge skin and with redesigned non-folding rounded wingtips..."

Zero Fighter, by Martin Caidin, Ballantine weapons book #9 ©1970. Page 158-159 shows a table that says:

"Experimental version with turbo-supercharger. Only two built. Basically an A6M2.

A6M1-2-2N Zero-Sen by Richard Bueschel, Schiffer, ISBN 0-88740-754-4, ©1995 (This book is a reprint with some minor updating from the original ©1970 Osprey and ARCO-AIRCAM publication). Pages 62-63 have a chart that shows the A6M4 and a footnote that says:

"Model 21 with turbosupercharger"

Zero: Japan's Legendary Fighter, by Robert C. Mikesh, Motorbooks, ISBN 0-87938-915-X, ©1994. Page 89 has a paragraph of text that says:

"The assignment of this designation to a Zero model has been in question for a long time, since no authoritative records have ever been found to prove its use. The designation may have been set aside for a proposed model that never materialized. Some think that it was associated with an A6M3 that was to be equipped with a turbo-supercharged engine, as suggested in 1968 by the Zero's designer Jiro Horikoshi. But the reason is not really known."

Famous Airplanes of the World - A6M models 22-63, #56, 1996. Page 14 has a brief paragraph, basically translated, that the A6M4 design has not been adequately researched.

Interestingly, there are virtually NO references to the A6M4 in Japanese texts.

At www.csd.uwo.ca/~pettypi/elevon/baugher_other/a6m.html

"By late 1942 and early 1943, the Zero Fighter was beginning to be confronted with newer, more-capable Allied fighters. At high altitude, the A6M2 and A6M3 were hopelessly outclassed by newer Allied fighters such as the P-38 Lightning and the F4U Corsair. In an attempt to correct this deficiency, two A6M2s were modified by Dai-Ichi Kaigun Koku Gijitsusho at Yokosuka to take an experimental turbosupercharged Sakae engine. The short designation A6M4 was assigned to this project.

"However, major teething troubles were encountered with the A6M4, and no production order was placed. As a substitute, the A6M5 interim version was introduced pending availability of the A7M Reppu." At A6M Zero

"A6M4 (2 modified A6M2's as prototypes) Turbosuper charged Sakae engine "

The most relaible source i know of on this subject is from a recognized expert who has corresponded as follows:

Jim Long of AIR'TELL Publications Research Service,

"At the time that I first read this explanation, I was skeptical of its validity, and as the years passed and no proof was forthcoming, I became even more uncertain. But after all of these years, I finally found a scrap of evidence to support René Francillon's pronouncement. It is fragmentary, but I think it is enough to make us all believe that there was something to the report of the A6M4. But what I've found is small and only gives evidence of the A6M4 designation in connection with an aircraft that had an intercooler, and which probably means that it had a turbosupercharged engine. There are no other details of that sort, however. We'll all be left with questions, I'm afraid.

"What I've found comes from microfilm reel JP-26 which contains images of Bulletins 67-45 through 78-45. These documents are CINCPAC-CINCPOA or JICPOA intelligence bulletins issued by the Intelligence Center, Pacific Ocean Area, or the Joint Intelligence Center, Pacific Ocean Area, or the Commander in Chief Pacific and Pacific Ocean Area. They are available to the public on microfilm from the Department of the Navy, Naval Historical Center, Washington Navy Yard, Washington, D. C. 20374-0571.

"I have excerpted the material of interest to you, and it runs as follows:

"Excerpt from CINCPAC-CINCPOA BULLETIN NO. 67-45, 30 MARCH 1945 QUARTERLY REPORT ON RESEARCH EXPERIMENTS VOLUME 1 SPECIAL TRANSLATION NUMBER 52

"QUARTERLY REPORT ON RESEARCH EXPERIMENTS

(Naval Air Technical Depot); dated 1 October 1942, Captured on SAIPAN.

whatever the truth about the A6M4, what we do know is that it never materialised. The Japanese were forced by that failure to try and extract as much as they could from an already proven failure....the A6M3

more to follow