The famous Mitsubishi A6M, popularly
known as the 'Zero', was the first carrierborne
fighter in the world capable
of outperforming any contemporary
land-based fighter it was likely to confront.
Because of inept Allied intelligence
it was able to achieve immediate
air superiority over the East Indies
and South East Asia from the day Japan
entered the war. Designed under the
leadership of Jiro Honkoshi in 1937 as a
replacement for the neat but obsolescent
A5M, the prototype A6M1 was
first flown on 1 April 1939 with a 582kW Mitsubishi Zuisei 13 radial;
production A6M2 fighters with
two wing-mounted 20mm guns and
two nose-mounted 7.7mm guns were fitted with the 708kW Nakajima Sakae 12 radial, and
it was with this version that the
Japanese navy escorted the raiding
force sent against Pearl Harbor, and
gained air superiority over Malaya, the
Philippines and Burma. In the spring of
1942 the A6M3 with two-stage supercharged
Sakae 21 entered service, later
aircraft having their folding wing
tips removed. The Battle of Midway
represented the Zero's combat zenith;
thereafter the agile Japanese fighter
found itself ever more outclassed by
the American F6F Hellcat and P-38
Lightning. To counter the new American
fighters the A6M5 was rushed to
front-line units; this version, with Sakae
21 engine and improved exhaust system,
possessed a top speed of 565km/h, more A6M5s (and subvariants)
being produced than any
other Japanese aircraft. It was five
A6M5s of the Shikishima kamikaze unit
that sank the carrier St Lo and damaged
three others on 25 October 1944.
Other versions were the A6M6 with
water-methanol boosted Sakae 31 engine
and the A6M7 fighter/dive-bomber.
Total production of all A6Ms
was 10,937. (The reporting name'Zeke'
was given to the A6M, and 'Rufe' to a
float version, the A6M2-N.)
| ENGINE||1 x Nakajima NK1F "Sakae 12", 705kW|
| Take-off weight||2410-2796 kg||5313 - 6164 lb|
| Empty weight||1680 kg||3704 lb|
| Wingspan||12.0 m||39 ft 4 in|
| Length||9.06 m||30 ft 9 in|
| Height||3.05 m||10 ft 0 in|
| Wing area||22.44 m2||241.54 sq ft|
| Max. speed||525 km/h||326 mph|
| Cruise speed||330 km/h||205 mph|
| Ceiling||10000 m||32800 ft|
| Range w/max.fuel||3050 km||1895 miles|
| Range w/max.payload||1850 km||1150 miles|
| ARMAMENT||2 x 20mm cannons, 2 x 7.7mm machine-guns, 60kg of bombs|
|A three-view drawing (752 x 1009)|
|David Strange, 13.07.2017|
I think one of the missed opportunity was replacing the Type 97 7.7x56mmR MG with the Type 2 13x64mmB MG as the cowling weapon in the A6M. The same could be said for the Aichi D3A and Yokosuka D4Y having their Type 97 replaced by cowling Type 2. But for some reason the Imperial Japanese Navy never adopted the Type 2 (German MG131) for the purpose it was originally designed for, a cowling machine gun. The improved hitting power made available to the Zero would have made a difference against the Grumman F6F Hellcat and F4U Corsair. U.S. Self sealing fuel tanks were good against Ball .50 ammo, not 13mm HE or HEI, and the 13mm API was effective against much of the armor on U.S. aircraft. It just seems like a missed opportunity to address one weak area of IJN aircraft which they had and failed to use.
The Zero may have had it's faults, but the skin being flammable (at least the assertion that it was more so than other aircraft of it's day) is s myth. If it was,the US being as obsessed with aircraft structural redundancy as they were wouldn't have used to make the B-50 bomber, (basically just an uprated B-29 made out of 7075 aluminum)not to mention M-16 rifles.
The A6M2 Model 21 Zero was able to turn a 360 in about 11 seconds, just about as well as the Ki 43-I Oscar, it's Army counterpart.
However, the Zero left the Oscar behind in speed, range, and firepower. Both lacked armor.
The Model 22 upgraded firepower with the slower but high velocity long range 20mm cannon, and combat range was restored from the penalty suffered by the clipped-wing Model 32.
Speed was better than the A6M2 as well as higher altitude performance (335.5 and 338.6 respectively vs 331mph).
After the prolific A6M5 lost the chance to upgrade to the 1,560 hp Ha-112-II engine planned by the design team, the Zero had crested already. Thus it only reached 351 mph and then declined in competence as it put on weight without more hp increase to compensate. The Navy pinned their hope on the methane injected A6M6 which failed.
The 348 mph A6M5a with more ammo and 346 mph A6M5b with thicker skin, still had no seat-back armor like the Oscar Ki 43-II had, and then the 336 mph A6M5c with armor and more guns, lost the speed advantage over the Oscar. With each improvement, speed was slower for the Zero. This disappointed the Navy so much that they relented and finally allowed the 1,560hp for the 357 mph A6M8, but that was only ready at the end (2 years too late). Meantime, the Allied fighters were leap-frogging the speed of both the Oscar and Zero which were still produced in 1945 but with 1941 performance.
Japan could have made better use of these resources by consolidating it's whole fighter industry to produce the best reliable engines and put them in the best fighters. All the rest of the production was inefficient and at cross-purposes if not outright obsolete. Japan had the reliable engine for the less than agile J2M5: 1820 hp Mitsubishi MK4U-4 Kasei 26a. The Ki 100 was a winning design but underpowered. Put them together and you have a high altitude interceptor better than either the Jack (Raiden) or radial Tony (Goshikisen) seperately. Now you have both a bomber interceptor and dogfighter in one. Put this on every fighter production line in Japanese territory starting before 1945. Now the B-29s have a high altitude threat, as does their escort! No Japanese single-seater besides about 35 J2M5s could approach that and they couldn't dogfight like a Ki 100! Imagine thousands of 1820 hp Ki 100s in place of all the others including the obsolete Zero and Oscar for the last half of WW2 or even the last year!
7.7mm Type 97:
7.7x56mm R Cartridge
800 rpm sync; 1000 rpm
HE 10.5g RETN/RDX
Faster RoF than Type 89 but less M/V.
The HE must be in the 20mm Type 99 cannon belt composition too, as I detailed (under the API). I should have written
2 API, 1 HE, 1 HET, 1 HEI.
The HE shell is most important.
The 13.2mm Type 3 HMG belt composition was 2 HEI, 1 TB, 1 AP:
48g Yellow HEI; 0.7g PETN; 1.6g Incendiary.
48.2g Red TB; 0.2g orange tracer lasts 8 seconds.
51.8g White AP.
A 51.6g ball round (Black) was also available.
792mps M/V. 800 rpm, synchronized 450 rpm RoF. Range 900m.
I believe a typical cannon belt composition for the Type 99 was 2 API, 1 HET, 1 HEI:
130.4g white API; 3.4g I (77.7% nitro).
124.7g dark brown HE; 10.2g PETN/TNT (60/40).
127.6g red self-desrtructing HET; 5.7g (5g PETN/0.7g gun powder); 5.5g T.
128.4g greenish-yellow with a white band HEI; 5g TNT; 3g WP & 1g Nitro incendiary.
There are 8 more choices of ammo too.
This RAAF source puts M/V of the Type 99 Mk I at 597m.
The range is 503m.
The Type 99 Mk II M/V is 743m. Range is 640m, at most (sounds low to me).
319 mph was for the A6M1 @ 11,811' alt.
A6M2 went 331 mph @ 14,927' alt.
unboosted of course.
The A6M2 max level speed was 319 mph @ 14,927'
Climb to 19,685/7 min. 27 sec.
A6M3-32 speed was 337 mph @ 19,685' alt/7 min. 19 ses.
A6M3-22 speed was 334 mph @ 19,685' ait
A6M5 speed was 351 mph @ 19,685' alt/7 min. 1 sec.
A6M5c speed was 336 mph @ 16,404' alt/5 min. 50 sec.
A6M7 speed was 337 mph @ 19,685' alt. 26,246'/9 min 58 sec.
A6M8 speed was 356 mph @ 19,685' alt/6 min. 50 sec. Climb.
The Mitsubishi A6M Reisen / Zeke’s strengths were also its Achilles heel. The reason for its fine performance was its light wing loading, giving it long range, a high climb rate, and expellant maneuverability. However, to achieve this it sacrificed pilot armor, self sealing fuel tanks, redundant structural members, and it used Magnesium, (a metal that burns ferociously when ignited), in its airframe. One of the main reasons it easily bested so many allied pilots early in the war was most fighter pilots had been taught the same “turn and maneuver” tactics that their fathers had used in 1917. If a pilot tried that crap against a “Zero”, he very soon found his foe was on his “six” throwing 20mikemike up his “kister”. General Chennault figured it out, before anyone else; you didn’t mix it up with Zeros. You dove through them, blazing away, kept going to gain speed, and then zoomed up at a safe distance to do it again. No one listened to Chennault at first because the serving officers in the US and UK air services figured, “What does an ex-Army Air Corps Colonel, serving as a mercenary in China, know about aerial tactics”. Once the allies started using appropriate tactics and started getting better fighters, the light Magnesium construction and lack of pilot and fuel tank protection came back to haunt Zero jockeys. With such a light airframe even the Zero’s long legs could cause problems; if a Zero suffered even moderate battle damage, and was 500 “wet” miles from a friendly landing area, its light structure might not hold together long enough to make it back to the barn. Because of this and the “Die for the Emperor” mentality of almost all Japanese military personnel, many pilots didn’t bother to wear a parachute. This willing omission practically guaranteed the loss of a fighter pilot for every Zero lost. The inadequate nature of war-time Japanese fighter pilot training, coupled with trained pilots going down with their crippled aircraft,(some lighting the sky like so many Magnesium flares), meant that eventually you had poorly trained Japanese rookies going up against highly trained, (and many combat veteran), US and British Empire opponents in the air. Check out the Marianas Turkey Shoot! In 1940 the Mitsubishi A6M was the finest carrier born fighter in the world, and probably one of the finest fighters in the world period. But by 1943 it was no longer the threat it had been, and by 1944 it was well past its prime. Unlike the Messerschmitt Bf 109 and the Supermarine Spitfire, the Mitsubishi A6M did have as much “stretch ability” in the original design; so unfortunately, like a lot of WWII aircraft, it was forced to soldier on past the point of obsolescence. You can only go so far relying on past glory to get by.
Climb rate for the A6M8 at 26,240' was 3140 fpm according to Green.
450 rpm was the RoF for the cowl Type 3 13.2mm HMG.
The IJNAF Zero fighter proved to be the master of early Allied fighters it met on it's debut in China.
The A6M2 was only successfully dealt with by the Flying Tigers with hit and run diving tactics. But most did not heed them when they warned the US about the Zero even before Pearl Harbor was attacked. For the next 6 months it took on all comers even virtually annihilating a Spitfire Wing in Burma!
The A6M2 Zero was the first strategic escort fighter with unbelievable range. Flights could last all day.
It was able to do a full 360 turn in about 11 seconds, but roll rate was bad with speed: 56 dgs/sec @ 160 mph and 37 @ 324 mph. Stick forces were so heavy over 240 mph.
Most all early Allied fighters had worse altitude performance than the Zero.
Zero pilots could reportedly get 345 mph with boost.
It could climb 4517 fpm, but dive limit was less than 410 mph.
It had 2 light MGs and 2x 20mm cannons (just like the Bf 109E). Ammo: 60 rpg for the 20mm and MV was low. RoF was slow too @ 520-550 rpm.
It's acceleration was excellent, giving Allied pilots the impression it was faster than their planes even if their top speed was higher.
Just like early war fighters in 1939 Europe, it had no armor. The Zero's defense was offence.
Just as important, it had many veteran pilots.
The A6M3 had 2 versions. First the clipped wing Model 32 which had improved dive limit of 416 mph and better altitude performance, roll rate and acceleration. But a full turn took over 12 seconds and climb was 3100-4500 fpm, still good enough but range was much shorter causing many losses.
So the more numerous Model 22 restored the full span and added fuel tankage to become the longest range Zero. Some had the new high velocity 20mm cannons, but RoF was slower @ 490 rpm. Most now had 100 rpg ammo.
By now the Zero had lost it's mystique as well as too many experienced pilots at Midway. Besides that, a second generation of powerful US fighters were overmatching the A6M in combat with the tactics like the Flying Tigers used. They avoided fighting the Zero's fight. Zero pilots had to be good deflection shots to score with only a 6 shell cannon burst against the well armored American fighters. especially feared was the Corsair, Lightning (up high), and British Spitfire Mk VIII.
The zenith of the Zero had been reached. Now it was on the defence and still no armor when all other Japanese fighters had at least some pilot protection by this stage.
Now came the most numerous A6M5 Model 52. The design team intended it to get a 1500+ hp engine upgrade but this was turned down by the Navy Brass! This combined with abbreviated pilot training, doomed not just the Zero but Japan.
It did about 350+ mph with the short span of the clipped Model 32. The Model 52 took over 16 seconds to complete a full 360 turn (the A6M5a,b,c and especially the A6M7 would take more time than the lighter A6M5). It also got 125 rpg for the cannons. With the A6M5b came bullet proof glass in front and some fire protection.
By the end of the war the last 240 Zeros (A6M5c & A6M7) finally got armored pilot seatbacks (but only about half the 16mm thickness in the Ki 61-II pilot armor) out of over 10,000 produced! This degraded their top speed to 340-345 mph but these could dive 460 mph. They now had at least 5 guns too. 13.2mm MGs were added, fist to the cowl (replacing one 7.7mm gun) with 230 rpg, later to the wings with 240 rpg. RoF was 800 rpm; 400 rpm synchronized in the cowl. Now overweight, it was obsolete, a shadow of past glory. Even the late model P-40N was a now a threat (at least down low)!
The IJNAF torch had long since been passed to the N1K Shiden fighter-bomber and J2M Raiden interceptor.
Rate of roll for the A6M2:
Best was at speeds much less than 160 mph, but at that speed it rolled 56 dgr/sec.
It really started to stiffen controls with speed:
52 dgr/sec @ 230 mph;
50 dgr/sec @ 250 mph;
37 dgr/sec @ 324 mph (NACA chart limit for Model 21 Zero).
Zero pilots likely preferred to stay far from 324 mph rolls, or even 250 mph. Who knows how good it rolled off the slow end of the NACA chart? None of the other fighters did their best rate under 160 mph so that's where the comparison chart starts unfortunately.
Of about 6,000 A6M5s, 470 were A6M5bfrom mid 1944;
93 were A6M5c from Sept, 1944.
These were produced after Jiro Horikoshi was replaced and, failing to get the intended Kinsei 62, were out-performed by even the Ki 43-IIIa in speed as well as max range, climb, acceleration and aerobatics. However the Zero had improved it's firepower and was catching up in protection.
Since Allied fighters were less agile, they tended to take straight shots especially the USAAF.
If the Japanese planes all added a cannon in the tail-cone, it could have played havoc with would-be assailants. Low percentage deflection shots would be resorted to even more by the Allied pilots.
Perhaps the obsolete Zero and Oscar would have had more of a fighting chance after the first year of glory. Even when diving away after attacking B-29s, a 30mm cannon stinger could give a telling parting shot from Japanese interceptors (perhaps a 37mm cannon on twin engine Japanese fighters). Any US escort fighter would be distracted if not intimidated.
As it was, the slow Zero and Oscar soldiered on beyond their prime and Japanese pilots liked it that way, unfortunately for them.
Perhaps this simple addition of a high velocity tail-stinger on ALL their fighters would have gone a long way to even the odds when Japan was thrown onto the defensive.
A6M3/5 pilots who didn't want to lose their speed would do fast yoyos and limit turns to 45 dgs. Over Okinawa some used fast barrel rolls and violent skids in the Zero. Energy tactics capilaizing on initial acceleration, but not as extended as the Allied pilots.
Anthony Cooper's 'Darwin Spitfires' site posts the RAAF Spitfire Vc Trop comparison with the Zero 32.
There it has the 1G stall speed of 55 knots per hour IAS or 63 mph for the Hamp and a max level speed of 291 knots or 335 mph @ 16,000' and a ceiling of 32,500'.
Though the Mk VcT had a speed and ceiling advantage, the Hamp was competitive due to it's lighter wing and power loading even around the Spit's critical altitude of 21,000' (5,000' higher than it's own). It's acceleration compensated up to 30,000' for speed limit disadvantage. A loop would cause the Spit to stall at the top if it followed. Even a dive initially favored the A6M3 due to acceleration not to mention the carb problem requiring the Mk VcT to half-roll first to dive. The Zero could do a negative-g dive no sweat.
The new engine of the Hamp gave it better altitude prowess than the old A6M2.
Perhaps the sluggish Mk VcT was the weak link in the chain of Spitfire contenders vs the zenith of the Zero Hamp before fading into obsolesence when the A6M5 was denied an engine upgrade.
Many are unaware of the fact that Zeros and Spitfires met in combat for 5 months of raids on Darwin, Australia.
I posted the mock dogfight evaluation by the RAAF between a captured A6M3 Hamp and a Spitfire Mk V Trop at the Spitfire site.
The pilots on both sides of the battle included many aces so they weren't below average, second string greenhorns as suggested by some after trying to rationalize the results.
The tactics had been already adjusted following the previous annihilation of a virtual Wing of Spitfires in Burma against Japanese pilots (Oscars mostly).
So the Spitfire pilots were overconfident, not expecting even a stand-off or draw this time.
Problem is the new cipped wing Zero 32 showed up!
It owned the Spitfire below 20,000'. But it avoided combat over 30,000'. Niether side could win.
Too many Spitfires were lost but they held the sky.
Thing is the lowly P-40E did better at Darwin than the Spitfire did against the Zero!
The Curtis lacked the climb rate and high altitude performance but had reliable guns that didn't freeze and malfunction up there either; it also had better acceleration than the Mk V tropicalized Spit, not to mention better dive and roll.
With enough warning both RAAF fighters could dive on the Japanese bombers with firing passes and escape the Zeros.
The following is from an AIAA report, dated 1976.
It was not until late 1942 that a captured Zero was made available to the U,S, Technical Intelligence Unit for flight test. Excerpts from the USATI are as follows.
The zero fighter is superior to all our present service type aircraft in regards to maneuverability. It is necessary to maintain a speed of over 3oo mph indicated tp successfully combat this aircraft. This superiority is recognizable in the fact that maximum manifold pressure can be maintained from sea level to 16,000 feet.
1 DO NOT ATTEMPT TO DOGFIGHT THE ZERO.
2 Never maneuver with the zero at speeds less than 300mph indicated
Never follow the Zero in a climb at low speeds. Service type ships will stall at the steep angle where the Zero has reached its most maneuverable point. At this point it is possible for the Zero to complete a loop and attack from the rear.
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