Corsair vs Zero

[Lightning Guy]

At least is was by the Americans.

The Oscar was numerically the most important JAAF fighter of the war and second overall to only the Zero. As RG noted it did turn better than the Zero but lacked the firepower. One other advantage it had over the Zero was the installation of early self-sealing tanks. Granted they were of a rather crude design but they were better than nothing.

 

[Gemhorse]

I always thought the '' meatball '' referred to the earlier US insignia of the white star with red dot in the middle, all set in a blue circle......

Gemhorse

 

[Lightning Guy]

I've never heard it called the "meatball." Of course that scheme was discontinued so as to avoid confusion with the Japanese insignia.

 

[R Pope]

The Oscar has been called the most maneuverable retracting-gear monoplane fighter ever built. In a dogfight it was supreme, but once the Yanks learned to keep their speed and not fall into a turning battle, they blasted poor old Oscar from the sky in droves.

 

[the lancaster kicks ass]

which was pretty mush their tactics with all jap planes as most could turn inside them...........

 

[evangilder]

At slower speeds, yes they could out-turn the American aircraft, but at higher speeds, they could not. This is well documented.

 

[Viper]

then when the zero is in the sights..... six 50cals opened up on them and theres no eascaping that.

 

[Gemhorse]

The 6x .50 cals served admirably against Japanese fighters, even the P-40 had it's way with them, it was the drain of seasoned Jap pilots who could really fly them, combined with more progressive models of solid Allied fighters, that exploited the weaknesses of Jap aircraft tactics [and they were wily! ], that tipped the balance, even in the face of their more desparate tactics....and it started with Chennault, and the guys he taught.....

 

[R Leonard]

Oh, my, what an interesting thread.

I'll throw in my two cents here and then another post to comment on some of the earlier posts.

The problem with the A6M series, and, indeed, most of the Japanese fighters at the beginning of the war, was that they were designed to fight a different war than what they faced against their eventual opponents. This was especially true for the A6M and though that's the airplane to which I will refer in most of this, the basic concept could be applied to the Ki-43. The A6M design was driven by a demand for a fighter that was both long ranged (a specification in which the Mitsubishi folks were singularly and notable successful . . . though not necessarily for the good) and a highly maneuverable aerial combat aircraft. The problem was that almost all was sacrificed for those two goals . . . very poor high speed performance, some loss of critical forward visibility, no armor protection, and inferior armament. Essentially, the A6M was a modern mono-wing fighter designed to fight in a WWI bi-plane tactics environment.

So, in order . . .

Very poor high speed performance –

Once the Americans learned to deny the A6M its low-speed maneuverability advantage, besting it became somewhat academic. Thus, the battle became one of tactics more than anything else. For the Americans, especially the USN and USMC pilots who were more likely to encounter A6Ms than any other Japanese fighter types, speed was life. As long as they kept their speed up, they might not shoot down an A6M, but they certainly wouldn't be shot down themselves. So, if caught in a really bad fix, a fast dive off to the right meant that the A6M, with its poor high speed performance, could not follow. This phenomena was a combination of the A6Ms inability to perform a right turn at speeds greater than 300 kts and the greater diving speeds of the American aircraft.

I offer the report of Lieut. Commander Eddie Sanders, the initial test pilot in his report of September 29, 1942 on the famous "Koga Zero" recovered from Akutan Island in the Aleutians:

"All controls are very light, free from friction and all are over-balanced statically. High maneuverability at normal speeds is obtained with small control movement. The ailerons are unusually long and lateral control is excellent right down to the stall. Aileron forces increase with speed. They are still fair around 200 KTS to 210 KTS, but at 230 to 250 KTS they practically freeze up and fast rolling cannot be done at 250 KTS. Could detect no buffeting or reversal at maximum displacement obtainable which is very small at high speed. The rudder is light and very effective. The elevator is the only control on which there is much change in trim with speed and power changes and that is not excessive. An adjustment elevator tab is the only tab provided. The others are fixed. Action from movement of any control is immediate.

"The plane handles remarkably like an SNC-1, feels about as light and maneuvers about the same. The main difference is in the ailerons where much less movement is needed for the rolling effect.

"The horizon was not working, but by estimating the angles, obtained 1.35 sec. to the right, and 1.1 sec. to the left for the standard rate of roll test in landing condition. The angle was probably more like 60 degrees. Rate of roll at 200 KTS was 5.4 sec. for 360 degrees. This was with not much more that half aileron displacement, but it was as far over as I could put it because of the high forces. Forces are higher to the right than left."

Some of Sanders' pertinent points in his evaluation were:

"Engine quits on push-overs"

"Ailerons get very stiff at higher speeds making fast rolls at high speeds (above 250 knots) physically impossible. At 200 knots the rate of roll (with ailerons) is slightly slower than an F4F. At lower speeds the Zero probably has an increasing advantage in any rolling maneuvers since it is highly maneuverable."

"Started getting considerable vibration and some flutter at 280 knots indicated. May be peculiar to this plane, but believe the diving speeds are probably considerably restricted."

"Believe F4F would accelerate faster in a dive and could roll or spiral at high speeds in such a way that a Zero could not follow because of aileron forces along [sic], if not speed and acceleration restrictions necessitated by strength limitations."

[NB: I believe the word after "forces" above should be "alone" not "along".]

My particular copy of the Sanders report has a cover distribution and memo dated November 29, 1942, from Headquarters, Allied Air Forces, South West Pacific Area, Directorate of Intelligence and signed by Major Frank T. McCoy, USAAC.

And from "Technical Aviation Intelligence Briefing #3" dated November 4, 1942 and published by the Navy's Aviation Intelligence Branch, Bureau of Aeronautics:

"Distribution - All ships and Units concerned with aircraft."

[. . . not bothering with background history information in the beginning of the report . . .]

"GENERAL: All metal low-wing monoplane, flush riveted with clean smooth exterior. Great emphasis has been given to saving weight wherever possible. Wing is integral with the fuselage, no leakproof tanks or armor, and wings fold only at tips. Landing gear, flaps and breaks [sic] are hydraulically operated. Visibility is excellent with no difficulty seeing astern. Cockpit is not much more cramped than a Spitfire, except that the longest pedal position is quite short and knees stick up rather high. Arrestor hook retracts into lower part of the fuselage. Flotation bag in rear of fuselage - watertight compartments in wings, outboard of cannons."

(Report continues with statistics on dimensions, weights, engine, propeller, armament, instruments, fuel capacity, and oil capacity. Then some fun stuff

"PERFORMANCE
"Maximum speeds and rates of climb are given below.
"Maximum speed.. Sea level.........270 (m.p.h.)
.........."..........."........5,000 feet.…..287......"
.........."...........".......10,000..."........305......"
.........."...........".....*16,000..."........326......"
.........."...........".......20,000..."........321.5..."
.........."...........".......25,000..."........315......"
.........."...........".......30,000..."........306......"

"Rate of Climb... Sea level..........2750 (ft/min)
....."...."......".......15,000 feet........2380......"
....."...."......".......20,000 feet........1810......"
....."...."......".......30,000 feet..........830......"

" * Critical Altitude.
"SERVICE CEILING: 38,500 feet."

The real good stuff in the report talks about the Zero's characteristics and comparison with the F4F-4 and the F4U-1. It echoes the Sanders report:

"CHARACTERISTICS:

"STABILITY: (a) Longitudinal stability is positive throughout. The elevator control is light and effective, and has very desirable control movement characteristics. (b) Directional stability is positive and control is light. There is no rudder trim tab and a moderate pedal force is carried in climb. (c) Lateral stability is positive in cruise condition and close to neutral in landing condition. Ailerons are abnormally large and the rate of roll at low speeds is extremely high. However the ailerons forces increase excessively with airspeed, and above 200 kts. indicated the airplane is very difficult to roll. At speeds above 250 kts. it is almost impossible to maneuver the plane laterally. At moderate to high speeds the rate of roll to the right is definitely lower that to the left, due to relative control forces.

"COMPARISON WITH F4F-4: The Zero is superior to the F4F-4 in speed and climb at all altitudes above 1000 feet, and is superior in service ceiling and range. Close to sea level, with the F4F-4 in neutral blower, the two planes are equal in level speed. In dive the two planes are equal with the exception that the Zero's engine cuts out in pushover. There is no comparison between the turning circles of the two airplanes due to the relative wing loadings and resultant low stalling speed of the Zero. In view of the foregoing, the F4F-4 type in combat with the Zero is basically dependent on mutual support, internal protection, and pull-outs or turns at high speeds where the minimum radius is limited by structural or physiological effects of acceleration (assuming that the allowable acceleration on the F4F is greater that that for the Zero). However advantage should be taken wherever possible, of the superiority of the F4F in pushovers and rolls at high speed, or any combination of the two.

"COMPARISON WITH THE F4U-1: The Zero is far inferior to the F4U-1 in level and diving speeds at all altitudes. It is inferior in climb at sea level. And inferior above 20000 feet. Between 5000 and 19000 feet the situation varies. With slightly more that normal fighter load, which may be distributed to give equal range and gun power, the Zero is slightly superior in average maximum rate of climb. This superiority becomes negligible at altitudes where carburetor air temperatures in the F4U are down to normal; close to the blower shift point it is more marked. However, the Zero cannot stay with the F4U in high speed climbs. The superiority of the F4U at 30000 feet is very marked and will persist at considerably higher loads. Attention is called to the fact that in the foregoing condition of loading all fuel in the F4U-1 is protected. In combat with the Zero, the F4U should take full advantage of its speed, and its ability to pushover and roll at high speed if surprised. Due to its much higher wing loading, the F4U should avoid any attempt to turn with the Zero unless at high speed, and may expect the latter to outclimb him at moderate altitudes and low airspeeds. In this case the F4U should continue to climb at high airspeeds and on headings which will open the distance and prevent the Zero from reaching a favorable position for diving attack. After reaching 19000-20000 feet the F4U will have superior performance in climb and may choose its own position of attack."

For comparison, the December 1942 US Army Air Forces "Informational Intelligence Summary No. 85 - Flight Characteristics of the Japanese Zero Fighter" was distributed to all USAAF squadrons. It summarizes the Sanders and Navy Comparison reports and provides comparisons with the P-38F, P-39D-1, and P-51:

"7. METHOD OF TEST:

"The Zero fighter was flown against the P-51, P-38F, P-39D-1 and a P-40F.

"Each of the above service type aircraft was flown with the "Zero" and comparable climbs, maneuverability, defensive and offensive tactics were determined from sea level to twenty-five-thousand (25,000) feet. The test was conducted in five-thousand (5,000) feet steps.

"Take-offs were started together and each climb was started from each ship's best climbing speed. Every effort was made to eliminate the possibility of zooming when the climb was started.

"Notes to the actual trials are set forth below.

"8. ZERO vs P-38F:

"Ships took-off in formation on a pre-arranged signal. The Zero left the ground first wand was about three-hundred (300) feet in the air before the P-38 left the ground. The Zero reached five-thousand (5,000) feet about five (5) seconds ahead of the P-38F. From an indicated speed of two-hundred (200) miles per hour the P-38F accelerated away from the Zero in straight and level flight quite rapidly. The Zero was superior to the P-38F in maneuverability at speeds below three-hundred (300) miles per hour. The P-38F could out dive and out turn the Zero at this altitude at speed above three-hundred (300) miles per hour.

"The planes returned to formation and both ships reduced to their best climbing speeds. Upon signal the climb was started to ten-thousand (10,000) feet. Again the Zero was slightly superior in straight climbs reaching ten-thousand (10,000) feet about four (4) seconds ahead of the P-38F. Comparable accelerations and turns were tried with the same results.

"From ten-thousand (10,000) to fifteen-thousand (15,000) feet the two airplanes were about equal. The Zero was slightly ahead, but not enough to be considered advantageous. Again comparable accelerations, speed, and maneuverability were tried with the same results.

"In the climb from fifteen-thousand (15,000) feet to twenty-thousand (20,000) feet, the P-38 started gaining at about eighteen-thousand-two-hundred (18,200) feet. At twenty-thousand (20,000) the P-38 was superior to the Zero in all maneuvers except slow speed turns.

"This advantage is maintained by the P-38F at all altitudes above twenty-thousand (20,000) feet.

"One maneuver in which the P-38F is superior to the Zero is a high speed reversal. It is impossible for the Zero to follow the P-38F in this maneuver at speed above three-hundred (300) miles per hour.

"The test was continued to twenty-five-thousand (25,000) and thirty-thousand (30,000) feet. Due to the superior speed and climb of the P-38 at these altitudes, it could out maneuver the Zero by using these two advantages. The Zero was still superior in slow speed turns.

"9. ZERO vs P-39D-1:

"Climb from sea level to five-thousand (5,000) feet indicated. Take-off was accomplished in formation on signal. P-39D-1 was drawing 3000 RPM and seventy (70) inches manifold pressure. Engine started to detonate so manifold pressure was reduced to fifty-two (52) inches. P-39D-1 left the ground first and arrived at five-thousand feet just as Zero was passing four-thousand (4,000) feet indicated. Fifty-two (52) inches manifold pressure could be maintained to four-thousand-five-hundred (4,500) feet indicated. At five-thousand (5,000) feet indicated from a cruising speed of two-hundred-thirty (230) miles per hour indicated the P-39D-1 had a marked acceleration away from Zero. Climb from five-thousand (5,000) feet to ten-thousand (10,000) feet at the respective best climbing speeds, (thus eliminating zoom) P-39D-1 reached ten-thousand (10,000) feet indicated approximately six (6) seconds before Zero. At ten-thousand (10,000) feet indicated, from a cruising speed of two-hundred-twenty (220) miles per hour indicated, P-39D-1 still accelerated away from Zero rapidly. Climbing from ten-thousand (10,000) feet to fifteen-thousand (15,000) feet, both airplanes maintained equal rates of climb to twelve-thousand five-hundred (12,500) feet. Above this altitude the Zero walked away from the P-39D-1. At fifteen-thousand (15,000) feet indicated, from a cruising speed of two-hundred-ten (210) miles per hour indicated the P-39d-1 accelerated away from the Zero slowly.

"Climb from fifteen-thousand (15,000) feet indicated to twenty-thousand (20,000) feet indicated the Zero took immediate advantage and walked away from P-39D-1. At twenty-thousand (20,000) feet indicated at a cruising speed of two-hundred (200) miles per hour indicated, and from a starting signal for acceleration, the Zero momentarily accelerated away from P-39D-1. It took P-39D-1 thirty (30) seconds to catch up and go by Zero.

"Climb from twenty-thousand (20,000) feet to twenty-five thousand (25,000) feet was not completed as P-39D-1 was running low on gasoline.

"Climb from sea level to twenty-five thousand (25,000) feet indicated. Take-off was accomplished in formation on signal, P-39D-1 left the ground with 3000 RPM and 55 inches manifold pressure. P-39D-1 maintained advantage of climb for take-off to fourteen-thousand eight-hundred (14,800) feet indicated. Above this altitude P-39D-1 was left behind reaching twenty-five-thousand (25,000) feet indicated approximately five (5) minutes behind Zero. At twenty-five-thousand (25,000) feet indicated from a cruising speed of one-hundred-eighty (180) miles per hour indicated Zero accelerated away from P-39D-1 for three (3) ship lengths. This lead was maintained by the Zero for one (1) minute and thirty (30) seconds and it took the P-39D-1 thirty (30) more seconds to gain a lead of (1) ship length.

"10. ZERO vs P-40F:

Tests were not completed with the P-40F because it was found impossible to obtain maximum engine operation.

"11. Zero vs P-51:

"Climb from sea level to five-thousand (5,0000 feet indicated. Take-off was accomplished in formation on signal. P-51 was drawing 3000 RPM and forty-three (43) inches manifold pressure. This low manifold pressure was due to the setting on the automatic manifold pressure regulator. The Zero reached its best climbing speed before the P-51 left the ground. The Zero left the ground approximately six (6) seconds before the P-51. The Zero reached five-thousand (5,000) feet indicated approximately six (6) seconds before the P-51. At five-thousand feet indicated for a cruising speed of two-hundred-fifty (250) miles per hour indicated, P-51 accelerated sharply away from Zero.

"Climb from five-thousand (5,000) to ten-thousand (10,000) and from ten-thousand (10,0000 to fifteen-thousand (15,000) feet produced the same results as Zero walked away from P-51 in rate of climb. At ten-thousand (10,000) feet indicated from a cruising speed of two-hundred-fifty (250) miles per hour indicated the P-51 accelerated sharply away from Zero. At fifteen-thousand (15,000) feet indicated from a cruising speed of two-hundred-forty miles per hour indicated the P-51 accelerated away from Zero, but slightly slower that at five and ten-thousand feet."

Particularly though, the report draws the following general conclusions and recommendations:

"Conclusions:

"The Zero fighter, because of its low wing loading, has superior maneuverability to all our present service type aircraft.

"It is necessary to maintain a speed of over three hundred (300) miles per hour indicated to successfully combat this airplane.

"In developing tactics against the Zero, cognizance should be taken of two facts:

"1. Slow rate of roll of the Zero at high speeds.

"2. Inability of the Zero engine to continue operating under negative acceleration.

"The engine performance of the Zero is superior to the present service type engine without turbo superchargers. This superiority is recognizable in the fact that the maximum manifold pressure can be maintained from sea level to sixteen thousand (16,000) feet.

"Recommendations:

"That the pilots entering the theater of action where the Zero can be expected be instructed in the following:

"1. Never attempt to dog fight the Zero.

"2. Never maneuver with the Zero at speeds below three-hundred (300) miles per hour indicated unless directly behind it."

"3. Never follow a Zero in a climb at slow speeds. (Service type ships will stall out at the steep angle where the Zero has just reached its most maneuverable speed.) At this point is possible for the Zero to complete a loop putting it in a position for a rear quarter attack."

In August 1942, in an interview with senior officers conducted in BuAer in Washington, DC, Lieut. Comdr. John Thach, just returning from the Pacific as CO of VF-3 reported his observations on action against the A6M:

" . . . Twenty Zero fighters hit my division from above and a few seconds later some more Zeros came in from the side to hit our torpedo planes. We were, of course, slightly outnumbered . . . " [Thach had but four F4Fs in his division and one of them was shot down in the first moments of the Japanese attack.]

"We were being attacked from above and from the side in rapid succession by the Zero fighters. There were so many fighters above us that they had to wait their turn to come in and attack. They usually try to make an approach from above and from the rear. By using the tactics which we have since incorporated into the Revised USF 74, we were able to defend ourselves . . . " [The tactics he refers to is the now famous 'Thach Weave' or, as he termed it the 'Beam Defense'.]

" . . . The three of us continued to fight for about fifteen minutes and then remained over the Jap ships five minutes longer, after the Zeros had stopped fighting us.

"Our tactics were always purely defensive. They were successful in keeping ourselves from being shot down, but we had little opportunity to use any offensive action, which we should have used, and should be able to use in a fighter. When we departed there were two Zeros above us and one below. We didn't take the bait." [Thach's "little opportunity to use any offensive action" accounted for at least five A6Ms shot down against his division's one initial loss.]

" . . . In connection with the performance of the Zero fighter, any success we have had against the Zero is not due to the performance of the airplane we fly, but is the result of comparatively poor marksmanship on the part of the Japanese, stupid mistakes made by a few of their pilots and superior marksmanship and teamwork on the part of some of our pilots. The only way we can ever bring our guns to bear on the Zero fighter is to do it when they are preoccupied shooting another one of our planes, or else trick the Zero into recovering in front of us.

"This deficiency not only prevents our fighter from properly carrying out its mission, but it has had an alarming effect on the morale of the fighter pilots in the Fleet at this time, and those who are going to be sent out to the Fleet. If we expect to keep our carriers afloat, in my opinion, we must supply a fighter that is superior in climb and speed, if not in rate of turn." [Of course by the time Thach gave his interview, the F6F was already on order and he had, the morning of the day of the interview looked over an F4U-1, but had yet to fly it.]

Later, in the question and answer portion of the interview Thach answered a question on A6M performance:

"Q. Do pilots think that the Japs had the same Zeros, the same type, at Midway as they had at the Coral Sea?
"A. No. There seems to be a little variation in the story on performance. Every pilot who came back from Midway stated that the Zero, even after the fighter pilot was on him and read to shoot, could climb right on up and away without any possibility of being caught by the Grumman. In the Coral Sea I believe several pilots stated they could stay with the Zero as far as speed was concerned and did a pretty good job of climbing at high altitudes. Of course, in the Coral Sea action we had mostly F4F–3's, but they're both so inferior to the Zero fighter that there's no use in trying to judge on of them over the other, there's no choice between the two, except the fact that the folding wing of the F4F–4 gives you a superior number – naturally we would take one.

Lieutenant Noel Gayler, a veteran of early actions with VF-3 and VF-2, in an BuAer interview in June 1942 commented in a similar vein:

"The Jap fighters have excellent performance; their rate of climb is as good as that of any plane I've ever seen. They can climb at an attitude that most planes won't climb in, and their general maneuverability is very good. They have big ailerons on the trailing edge and are extremely maneuverable. The Jap pilots, however, make mistakes and quite often give you a good shot at them."

So now we have a general idea of the characteristics of the A6M2. Note the dates of the USN and USAAF reports. These reports were printed up and rapidly distributed to deploying squadrons and undoubtedly saved some lives. The Zero was designed to relatively low speed, acrobatic dog fighting a la the First World War, a concept that rapidly going out of date when the war broke out in the Pacific and was totally out of date by early 1943. Japanese doctrine and tactics were hand-in-hand with this outmoded thinking. The result was, divorced from the structure of divisions and sections (another subject altogether) and tactics in general, was an aircraft that could not perform aileron turns at high speeds and an engine that cut out in high speed push-overs.

Loss of critical forward visibility:

The position of the pilot and the geometry of the nose of the A6M made moderate to high deflection shots a little difficult. In these situations the pilot had to drop his nose to see his intended target then bring it back up in order to fire at a point in space where he expected his victim to be when his bullets got there. As a result, the victim in such situations was briefly out of the A6M driver's field of vision. This is why USN/USMC pilots were taught to, whenever possible, show an attacker a full deflection angle. In the situation with the A6M this was important as an alert pilot, seeing an A6M coming in on a full deflection run could actually see the nose drop and then come back up. As the nose came up, the now alert victim momentarily out of the view of the A6M driver could to breakaway in another direction, preferably down and to the right. This was not a hard concept to sell to the USN/USMC fighter pilots as they were trained in deflection gunnery. The Japanese propensity for the overhead and from the rear attack, a zero-deflection solution, indicates that they (the Japanese) were obviously aware of the problem. Gayler commented on the effectiveness of the favored Japanese approach:

"A typical attack is for them to take the topside from you if they can and come out on your tail at so much speed that they overrun. That's a typical mistake they make. Realizing they're in a bad spot they will pull out directly in front of you. They climb so fast that they open the range on you as you're shooting at them. About the time you get well on them your Grumman [Gayler is referring to the F4F-3] will run out of flying speed and you drop out of it. Then they come back at you. However, they do give you a good shot at them and if you can shoot you should be able to hit them."

Thach commented on the superiority of the F4F and in the full deflection solution in this regard:

"Also one thing that was particularly desirable on the Grumman airplane was the 6½ degree angle downward from the sight to the nose which allows the pilot to see the enemy target before he opens fire on it.
"In an overhead approach or beam shot it's necessary to lead the plane a great distance. It's necessary to put the sight 'way ahead and give the plane too much lead and let drift back, because once you have not enough lead you can never pull up again."

The later F6F also had the down angle from the site to the nose, although it was not as pronounced as in the F4F. Thach also commented on this particular design feature as related to the F4U:

"In the F4U I understand that the cowling comes up to cut the 100–knot ring. It will be extremely difficult with that to make those particular deflection attacks – and they are the ones in which we encounter practically no free gun opposition, and which we usually get a chance to make."

Thus the length of the nose of the F4U may have presented a full deflection shot limitation. My primary source, a pilot with considerable experience in the F4F, F6F, and F4U (not to mention some 47 other types and 34 variants of 16 of them) tells me that it turned out to be not that much of a problem, one that was resolved by the elimination of the early "birdcage" canopy and raising of the pilot's seat, and other less noticeable modifications, found in what became known as the F4U-1A.

No Armor:

The lack of protective armor for the pilot and critical fuel systems made the A6M a death-trap if it came under serious fire for more than just a few seconds. The airplane's only real defense was its maneuverability. If caught by surprise or at a disadvantageous maneuvering position, under the fire from the standard USN fighter 6 .50 cal M-2s, there was usually no escape. Thach spoke on the efficacy of the US fire on the Japanese fighter:

"Q. Are present gun combinations effective? What combination would you prefer to use?
"A. Our present gun combination is very effective. Naturally, it's better if you can have your guns in the fuselage, directly along the sight. As far as the number of guns is concerned, I would like to have six .50 caliber guns, provided the performance of my airplane was superior to that of the enemy. If it's inferior, I would say that four .50 caliber guns was optimum. If taking out two .50 caliber guns, or having two .50 caliber and two .30 caliber will make it easier to get on the tail of an enemy fighter, I will accept that. I know you can hit better with guns close to the sight and directly parallel to it. It's just like you handle a shotgun shooting ducks.

"Q. It has been brought to our attention that one method of combating these Zeros, after you have made a leak in their gas tank is to direct the tracer aft and below into the slip stream and that would cause it to blow up.
"A. That's true of any Japanese, or any other aircraft, when gasoline is seen streaming from any point the thing to do is to aim at that white vapor and try to hit it, aim at that spot and a satisfactory fire will result.

"Q. What is the minimum ammunition you need per gun?
"A. In a fighter I would like to have 500 rounds per gun, but would be satisfied with 400.

"Q. What sort of firing do you have in combat, short bursts or what?
"A. The experienced fighter pilot will fire only when he knows he's on and hitting. In fighting the Zeros sometimes we – well, I might say most of the time, we get only what we call snap–shots or pot–shots at them when they're climbing vertically away from us, and those shots are as far away as 400 yards. They can be effective that far away, but the lead must be exact and it's difficult to hit an airplane at that range. We have knocked them down at 400, but we like to get in closer of course, but the performance of our airplanes won't let us.

"Q. How about tracer ammunition in fixed guns?
"A. We use it. It is excellent to determine any error in deflection. We don't particularly trust it in range, although if the tracers appear to be going ahead of the target you know they are probably going in. If they appear to going in the target in range you know that they're going astern.

"Q. If you had a given amount of ammunition would you prefer to have a less number of guns and more rounds per gun or more guns?
"A. I feel that four .50 caliber guns is optimum considering this performance problem we have. I believe that two are not enough. I would rather have four guns and 400 rounds per ammunition than six guns and only 250 rounds.

Gayler commented in his interview: " . . . the Zero fighter is apparently not protected at all . . ." and in the same breath mentioned the A6M's armament on which more later, ". . . and in addition it has very poor armament; two light machine guns and two slow firing 20 mm cannon which are not as damaging as you might think, even if they get hits. And they don't get hits."

Both Thach and Gayler were career naval officers, both of whom retired as four-star Admirals. Gayler's last comment leads us to the subject of inferior armament.

The A6M2 carried two 7.7 mm Type 97 machine guns firing through the propeller arc and in each wing one 20 mm Type 99-1 cannon. The nose mounted 7.7 load out was 500 rounds each, while the 20 mm load out was 60 rounds per gun. So already we can see a somewhat inferior load out in 20 mm ammunition. Additionally, against the armor of the typical USN fighter, absent a lucky hit, the 7.7 was relatively useless and served to simply warn a, perhaps inattentive, pilot that he was under attack. When you examine the specifics of the weapons operation the picture becomes even more dismal. The 7.7s had a rate of fire of 1000 rounds per minute (r/min). That meant there was only 30 seconds of firing time or only about 17 rounds per second per gun (r/sec/gun). The Type 99-1 20 mm had a low rate of fire, only 490 r/min, resulting in about 7 seconds of fire which works out about 8 r/sec/gun. The disparity in duration led the A6M drivers to usually use their 7.7s to range in on a target and then, when close, cut loose with the 20mm's to minimize firing time and at the same time make up for the Type 99-1's somewhat poor range. Significantly, the weight of an A6M2's fire, i.e., one second of fire, came out at 5.76 pounds.

Later A6Ms, such as the A6M5c, carried a heavier armament, in this case a 20 mm Type 99-2 cannon and a 13.2 mm Type 3 machine gun in each wing, plus a single 13.2 mm Type 3 firing through the propeller arc. The Type 99-2 was an improvement over the -1 and was belt fed (as opposed to the -1's magazine feed) with 125 rounds. The Type 3 machine guns were similar to the US M-2 .50 cal Browning in both appearance and performance. Their load out, both wing and nose was 300 rounds. The Type 99-2 20 mm's 125 rounds with an r/min of 750 resulted in an available 10 seconds of fire at a little better than 12 r/sec/gun. The Type 3 13.2 mm machine guns had a r/min of about 800, or about 13 r/sec/gun for about 23 seconds. Again, the A6M 20 mm would run out before its other weapons, but the 13.2 mm was a marked improvement in hitting power over the Type 97 7.7 mm. The fire weight of the A6M5c works out to 7.68 pounds.

On the other hand, the various USN and USMC adversaries of the A6M series were armed with the M-2 .50 cal. Browning machine gun, first developed in 1918 (and still in use today). Their similar statistics were:

F4F-3:
2 .50 cal. per wing; 460 rounds per gun
Rate of fire: 700 r/min
Firing time available: 39 seconds; 12 r/sec/gun
Weight of fire: 5.35 pounds

F4F-4:
3 .50 cal. per wing; 240 rounds per gun
Rate of fire: 700 r/min
Firing time available: 21 seconds; 12 r/sec/gun
Weight of fire: 8.01 pounds

F6F-3 and F6F-5:
3 .50 cal. per wing; 400 rounds per gun
Rate of fire: 700 r/min
Firing time available: 34 seconds; 12 r/sec/gun
Weight of fire: 8.01 pounds

F4U-1, F4U-4, and FG-1:
3 .50 cal. per wing; 400 rounds per gun
Rate of fire: 700 r/min
Firing time available: 34 seconds; 12 r/sec/gun
Weight of fire: 8.01 pounds

FM-2:
2 .50 cal. per wing; 400 rounds per gun
Rate of fire: 700 r/min
Firing time available: 39 seconds; 12 r/sec/gun
Weight of fire: 5.35 pounds

This means, with the exception of the F4F-4 the USN/USMC fighters enjoyed a longer available firing time. Significantly, for the F4F-4, F6F -3 and -5, and F4U-1 and F4U-4, there was a marked advantage in the number of rounds through the barrel. One second of fire from each of these airplanes would generate some 70 rounds heading for a target. This was more then 22 r/sec greater than the A6M5c and 24 r/sec then the A6M2. The F4F-3 and the FM-2 could generate a respectful battery of 47 r/sec, which while on par with the A6M5c, exceeded the A6M2 In either case, their total firing time available exceeded that of the A6Ms. The F4F-3 was out of front line service after June 1942.

In effect, the A6M was an airplane that was only truly effective if you played by its rules, any departure from the Zero's optimal performance envelope drastically reduced its combat maneuvering effectiveness. It's lack of armor protection meant it was fatally vulnerable to even short bursts of fire, especially from the .50 cal Brownings mounted in its USN/USMC adversaries. While the early use of the 20 mm cannon was perhaps a harbinger of future fighter aircraft, the Japanese versions were less then effective in terms of range and basic load out. This meant the Japanese pilot had to close with his adversary in order to insure hits and conserve ammunition. This often led to target a target fixation that left them particularly vulnerable to such maneuvers as the "Thach Weave," a simple break-away in a full deflection situation, or, as the war went on, a knowledge on the part of the Americans of what the A6M drivers would probably do in a give situation. For the Americans, all this increased one's chances of, at least, escaping being damaged or shot down and, at best, turning the tables and damaging or shooting down the Zero.

Regards,

Rich

 

[R Leonard]

Okay, now some comments on posts:

Lightning Guy's post of Thu Jan 27, 2005 9:53 pm
And if you want to discuss the Zero vs. the Corsair, check your info. The Corsair was powered by a R-2800 Double Wasp which intially delivered 2,000hp though late-war models had this up to 2,850hp with water injection. The R-4360 Wasp Major to which you refer was only fitter to the F2G the grand production total of which was exactly 10 units with no combat time recorded.

Absolutely correct in all respects. The A6M was designed based on specifications drawn up by the IJN and independent of any foreign influence . . . except maybe in instrumentation . . . the altimeter of the famous "Koga Zero" clearly had a Sopwith logo on the back . . . and maybe the propeller, which was a Hamilton-Standard knockoff.
F4Us used during the war were powered by the R-2800, as was the F6F.

The Jug Rules! post of Fri Jan 28, 2005 12:17 pm
Aren't we forgeting someone? Even the lowly wildcat had a great combat record against the zero.

Certainly my favorite. Indeed, the F4F, in the first year if the war managed to maintain a 1 for 1 victory to loss ratio with the A6M2. This was a rate that, while unhappy in terms of absolute numbers, the Americans could afford, but the Japanese could not.

plan_D post of Sat Jan 29, 2005 1:11 am Post subject:
The AVG, RAF and IAF would have met plenty of Zeros though. As Nagumo went around to the Indian Ocean with 5 aircraft carriers and supported Japanese Army movements. The Akagi was attacked by 11 Sqn. Blenheims at one point, obviously supported by either AVG P-40s or Hurricanes (Possibly Buffalos)

It has been pretty well established that the AVG, which did not enter combat until 20 Dec. 41, fought only against the IJAAF and not against the IJNAF. AVG fighter to fighter actions were against Ki-27s and Ki-43s. I suggest a look at Dan Ford's "Flying Tigers" in which he identifies the squadrons and types involved in each of the AVG actions.

lesofprimus post of Sun Jan 30, 2005 10:07 pm
In the early years of the war, the Allies basically had the use of 4 aircraft, the Buffalo, P-36, P-40, and the Hurricane..... None of these aircraft could handle a dogfight with an experienced Zero pilot....

There was the F4F, of course, as well.

From same post:

After Petty Officer Koga was forced to land on a remote island in 1942, and the first captured Zero was in the hands of the Allies, America was able to design the next generation of fighters to combat the weaknesses of the Zero.....

Not really. The only development of a US fighter ever connected, however erroneously, with the recovery of the "Koga" or "Aleutian" Zero was the F6F. The association of the development of the Grumman F6F-3 with the restoration of #4593 A6M2 is one of the great urban legends of WWII. Nothing of the kind happened. Other then the fact that the Navy knew the F4F was just holding its own against the A6M2 and needed replacement with something better, the A6M2 had absolutely nothing to do with the development of the F6F and, specifically the "Koga" or "Aleutian" Zero had nothing to do with its development.

The only USN/USMC fighter combat experience at with the A6M at the time that Koga's plane was being recovered, and at the time the XF6F was being first flown, occurred with the VF squadrons that fought at Coral Sea, VF-2 and VF-42, and the VF squadrons at Midway, VF-3 (and 59% of the combat flying pilots in VF-3 were from VF-42), VF-6 and VF-8. By the time the F6F-1 was ready to take to the air, the after action reports from these actions had yet to be distributed. Further, having read those reports, I can safely say that there is not much in them at all that could possibly be of interest to a Grumman designer, especially since the F6F-1 was already built.

The "Aleutian Zero" was # 4593, recovered, shipped, and restored by US Navy personnel at North Island NAS, San Diego, California. Grumman had absolutely nothing to do with the restoration. It first flew with a US pilot (Lt Cdr Eddie Sanders) on 20 September 1942. My father's log book show that he flew this same airplane on 14 September 1944, 19 September, 14 October, 21 October, and 25 October 1944. It was destroyed in a taxiway accident in February 1945. My father salvaged the port wingtip and some instruments all of which he donated to the USN Museum at the Washington Navy Yard in the mid-1980's.

The US Navy asked Grumman to start the design of the F6F in June 1941 as a hedge against problems with the development of the Chance-Vought F4U which was scheduled to replace the Grumman F4F series. Grumman was already out of the starting blocks on this having begun studies on a concept for an improved F4F in early 1938; by 1940 the concept had received a company designation of G-50. The Navy's order of 30 June 1941 was for two of the G-50 models, now designated as the XF6F-1 and the XF6F-2. As things turned out having Grumman design its own replacement for the F4F was a good idea as there were development and deployment problems with the F4U.

The Grumman XF6F-1 first flew almost a year later, on 26 June 1942, (20 days after the Battle of Midway and 7 days after VF-3, VF-6, and VF-8 arrived back at Pearl Harbor), with a Wright R-2600 engine. Even at that time, it was already obvious that the 1600 hp R-2600, in either its R-2600-10 version in the XF6F-1 or its R-2600-16 version in theXF6F-2, was not going to provide the speed desired for the airplane. The solution, which Grumman had already identified, was a switch to the 2000 hp Pratt Whitney R-2800 engine. The XF6F-1 flight with the R-2600-10 was essentially a test to verify what Grumman and the Navy already suspected, the need for more power. The XF6F-3, the re-designated XF6F-1 now mounting the R-2800 engine, first flew on 30 July 1942. This was almost two months before A6M2 # 4593 got into the air over North Island. The F6F-3 was version of the Hellcat that first entered combat and of which some 4403 were produced. The Navy, with remarkable prescience, placed its first order for the F6F-3 on 23 May 1942, before any version ever got in the air (and two weeks after USN fighter pilots had encountered the A6M2 for the first time at the Battle of the Coral Sea).

The F6F was developed independent of the restoration of the A6M2 # 4593 and most, if not all of the basic design work accomplished long before the USN VF squadrons first ran into the A6M2 at the Battle of the Coral Sea in May 1942.

Suggest you look at

"Koga's Zero" by Jim Rearden (originally published as "Cracking the Zero Mystery"), ISBN 0-929521-56-0, published by Pictorial Histories Publishing Co., Inc., Missoula, MO.
and
"Hellcat – The F6F in World War II" by Barrett Tillman, ISBN 0-87021-265-6, published by Naval Institute Press, Annapolis MD

These two works should clear up any ambiguities on this matter.

Regards to all,

Rich

 

[R Leonard]

And a last commentary evaluation of the A6M2. Here's the comments made by an experienced USN fighter pilot, an ace with 2 A6M2's to his credit that give a nice general evaluation of the A6M2 and my usual source for period comments (from an original letter):

"I first saw the captured Zero as a pile of salvage shortly after it arrived from Alaska. Soon after I was sent to the Southwest Pacific and didn't see the plane again until August 1943 when I was assigned as fighter training officer at San Diego.

"The Zero had gone to Tactical Air Intelligence Center and was based at Anacostia Naval Air Station, near Washington, D.C. After Sanders, Hoffman, and others tested, compared, and evaluated the airplane, the Army put it though similar paces.

"While fighter training officer at San Diego, I learned that Koga's Zero was still at Anacostia, airworthy, but unused. I arranged for it to be flown to San Diego. The Zero 21 was a mighty sweet machine, even in its superannuated state. The refined aerodynamic design was not compromised by mass production. Fit and finish of all plates, rivets, the close and accurate fit of fairings, engine cowl, access plates, canopy, and wheel doors were most faithfully executed.

"The propeller spinner faired into a cowling that smoothed the contours of the reduction gear housing of the engine. The interior aerodynamics of the engine cowling permitted the adequate cooling of the two-row 14-cylinder engine with a remarkably small intake. Contrast that with the inlet on the F4F-3 and -4 which originally came with a spinner but had to sacrifice it to cure engine overheat problems. The Sakae engine looked and sounded much like our R-1830. It ran smoothly and cool. Displacement was somewhat less that the Pratt and Whitney 1839, but its 1130 hp was smoother and adequate. It was not supercharged as extremely as the R-1830-76/86 and at very high altitude (over 30,000 feet) compared very poorly with the Pratt and Whitney. But we hardly ever encountered Zeros above 10,000 feet with our F4F-3s and -4s, so we were carrying supercharger hardware as extra baggage. The F4F, which became the FM-2, was re-engined with the Wright R-1820 with about the same power as the R-1830, but much less supercharger. This was a better machine to fight Zeros with, but we didn't get in squadrons until 1944, and by that time the Zero was not the problem it had been in the beginning.

"By the time I was flying the Zero 21 it may have had some of its automatic systems disabled. An example is the automatic altitude compensation of carburetor mixture. The first time I went for altitude the engine began to cut up disgracefully above 5000 feet. Worried that the engine was giving up, mixture came to mind. On this machine full rich is a rearward position of the mixture control. Manual leaning comes by easing this control forward. On doing this gingerly the engine smoothed up beautifully and the airplane jumped ahead with about 500 more horses - no less.

"The propeller was auto hydraulic cum Hamilton – no mysteries. We ran the engine as though it was an R-1830, but did not let the RPM go over 2600.

"The case of the manifold pressure gauge had been cracked in the crash at Akutan and it leaked. It was left in the instrument panel, but we used a standard AN type attached to a bracket nearby.

"The throttle sat in a quadrant outboard of the mixture control. It was shaped like the handle of a knife – complete with wood side plates for contour. It was about five inches long and on the top had a switch to be operated by the left thumb. This switch was for cutting in or out the 20mm cannon.

"The Zero carried many rounds of 7.7mm for the two fuselage guns and only 80 to 100 for each of the 20mm wing guns. Ergo, sight in with the 7.7 then cut in the two 20s for telling shots. I dimly remember there was a trigger lever you could pull up and squeeze on the front edge of the throttle. If you were not in combat, this lever would drop down where inadvertent firing was precluded (we had sad events because the trigger on the stick of U.S. fighters was easily squeezed in excitement).

"Cockpit was not so tidy as the F4F, but easily as tidy as the F4U and earlier Vought birds. Instruments were much like ours, but metric for pressures, temperatures, [and] altitude. Airspeed was in knots. It had an inner and outer scale as the needle needed to go around about 1½ circles to get to the high end of the scale.

"In the Zero 52 there was an exhaust temperature gauge as well as the usual cylinder head temperature gauge. My guess is that it was a refinement to fine tune the mixture to get the remarkable endurance and range the Zero was famous for.

"Gyro horizon had a sky blue upper half like some of the German WWII instruments I have seen. To the envy of every F4F pilot, the landing gear was hydraulically actuated!

"Tail wheel was fully retracted behind tight doors. Tail hook was faired into a recess along the keel. The hook was hinged on the end of its strut, latched in the snatch position to catch the wire then dumped, so the Zero could taxi forward over other wired unimpeded. I understand we toyed with this idea but gave it up because of worries it might misbehave and cause an unarrested landing.

"Brakes were hydraulic – weak. The wide tread and relatively low landing speed favored weak brakes so you might say they were adequate. Rudder bar was center-pivoted with stirrups for each foot. Brakes were actuated by a hand lever; rudder angle determined which wheel received braking action.

"The canopy gave a beautiful view of the outside world, noticeably good to the rear in contrast to our VF's. The enclosure was made up of many panes of plexi, some contoured. Wind noise was moderate. Some of the enclosure had been destroyed and was remade by A and R.

"The windscreen section was original, for it bore deep craters from the corrosion that took place during its dip into the marsh of Akutan. These cavities had a way of coming into focus when air speeds built up. I often wondered why they had not been replaced by A and R. In VF-42 we had some nasty experiences with the original F4F windscreens blowing out on use when flying at more that 300 knots. Grumman corrected it with a beef-up that robbed us of valuable forward vision, but it ended the problem. The Zero had no such heavy structure in the first place, so it was a source of uneasiness.

"The Zero 21 had no primer for engine starting. The carburetor had a large capacity acceleration pump you feel when you moved the throttle. To start, you had the mechanic wind up the inertia starter as you wobbled up fuel pressure and work the throttle two or three times to spray in the discharge of the accelerator pump. On contact the engine rolled over readily, caught, and picked up to run without complaint.

"The carburetor barrel has an oil jacket through which circulated lube oil to combat any tendency to form ice. I'm not sure whether it was always in action of selectable from the cockpit. We never touched it as I remember. Seems a tidy way to handle ice.

"In February-March 1945 I had a dandy low-time fresh-caught Zero 52 to fly. It was much like Koga's Model 21, but heavier because of two more guns. It had a hundred or so more horses, and ejection type exhaust stakes, but flew essentially like the Model 21 – very sweet."

Regards,

Rich

 

[trackend]

Very interesting R L. Thanks for the infomation a well researched and informative artical I shall add this to my personal aircraft data base.

 

[cheddar cheese]

Some great info there RL...

 

[evangilder]

Rich, that was a very good evaluation of the Zero's performance. You obviously put alot of time and research into the above. Nice job.

 

[Soren]

Hello

Regarding the Zero vs Corsair:

The Corsair is the superior fighter because of its much higher speed and better roll rate. However the Corsair was only superior because of the Hit and run tactic utilized by allied pilots against the 'Zeke'.
However if you get into a dogfight with the 'Zeke' your in deep truble ! And if you try and turn with the 'Zeke', your dead meat Even the Spitfire IIV would be dead meat against the 'Zeke' in a turning dogfight, wich the british learned the hard way !. The rule set for allied pilots was "Never" to turn or climb with a 'Zeke', as "NO" allied fighter could turn inside the 'Zeke'. Although the 'Zeke's' turning ability started drop at speeds over 275mph, it would still turn tighter than any Allied fighter at high speed (The 'Zeke' could normally only reach 331mph, so it wasnt fast, and this should be its downfall later on)

These are some of the reasons that early in the pacific war, the 'Zeke' was regarded as "indestructable" by allied pilots.
However later on the U.S. developed tactics to defeat the 'Zeke', like the "Thach Weave" tactic. With these new tactics the Zero's days of indestructability were severely numbered !

Overall the Corsair is a better fighter than the Zero in many ways, however it would mean almost certain death for the Corsair to get into close dogfight with the Zero (wich is why allied always always used the Thach Weave tactic when facing a Zero.

Cheers

 

[plan_D]

What exactly is a Spitfire IIV?

The Spitfire V and VIII which were sent out in 1943 got a 8:1 kill ratio over Japanese planes. There's no hardship there...

 

[Soren]

What exactly is a Spitfire IIV?

Sorry, i ment Spitfire VII Damn those roman numerals !

The Spitfire V and VIII which were sent out in 1943 got a 8:1 kill ratio over Japanese planes. There's no hardship there...

Yes japanees "planes" But when they incountered the the 'Zeke' they were in trouble !, except if they sticked to the Shoot and scoot tactic ! But if the Spitfire tried to turn with the Zero, it was as good as dead !

Also it is important to note that in 43 the Japanees fighter-pilots werent as properly trained as in 41 for example.

Overall i would rather be in the Spit though, as its wings wouldnt be ripped up at 370mph as the 'Zeke's' would

 

[plan_D]

It wasn't in trouble when it met Zeros, the Spitfire was just a better plane overall.

 

[Soren]

It wasn't in trouble when it met Zeros, the Spitfire was just a better plane overall.

Well if the Spitfire engaged in a low altitude dogfight with 'Zeke', and the 'Zeke' is on the Spitfire's tail, then i dont see how the Spitfire would ever get out of harms way ! It cant dive away because there isnt space enough. And it cant climb away as then the Zero will catch it with ease ! And it cant make a sharp turn, as the Zero would have no problem what so ever following the turn, thus that would be the same as turning yourself into gunfodder

The Spitfire's only chance of escaping a 'Zeke' that is on its tail is to dive, if the altitude allows it

 

[The Jug Rules!]

The AVG, RAF and IAF would have met plenty of Zeros though. As Nagumo went around to the Indian Ocean with 5 aircraft carriers and supported Japanese Army movements. The Akagi was attacked by 11 Sqn. Blenheims at one point, obviously supported by either AVG P-40s or Hurricanes (Possibly Buffalos)

I don't think it was the AVG. I don't think they ever encountered a Zero.

=S=

Lunatic

Wait a minute. I read "God is my Copilot", and I can remember plenty of times when R.S.Scott brought his bird back with CANNON holes in it. Now, the Oscar at its best only had 2 .50 cal guns. His personal fighter was put out of action because of structural damage caused by cannons. Where's all the cannon damage coming from?