Mitsubishi A6M Zero

https://en.wikipedia.org/wiki/Mitsubishi_A6M_Zero

The Mitsubishi A6M "Zero" is a long-range fighter aircraft formerly manufactured
by Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and
operated by the Imperial Japanese Navy from 1940 to 1945. The A6M was designated
as the Mitsubishi Navy Type 0 carrier fighter (??????? rei-shiki-kanjo-sentoki),
or the Mitsubishi A6M Rei-sen. The A6M was usually referred to by its pilots as
the Reisen (??, zero fighter), "0" being the last digit of the imperial year
2600 (1940) when it entered service with the Imperial Navy. The official Allied
reporting name was "Zeke", although the use of the name "Zero" (from Type 0) was
used colloquially by the Allies as well.

The Zero is considered to have been the most capable carrier-based fighter in
the world when it was introduced early in World War II, combining excellent
maneuverability and very long range. The Imperial Japanese Navy Air Service
(IJNAS) also frequently used it as a land-based fighter.

In early combat operations, the Zero gained a reputation as a dogfighter,
achieving an outstanding kill ratio of 12 to 1, but by mid-1942 a combination of
new tactics and the introduction of better equipment enabled Allied pilots to
engage the Zero on generally equal terms. By 1943, due to inherent design
weaknesses, such as a lack of hydraulic ailerons and rudder rendering it
extremely unmaneuverable at high speeds, and an inability to equip it with a
more powerful aircraft engine, the Zero gradually became less effective against
newer Allied fighters. By 1944, with opposing Allied fighters approaching its
levels of maneuverability and consistently exceeding its firepower, armor, and
speed, the A6M had largely become outdated as a fighter aircraft. However, as
design delays and production difficulties hampered the introduction of newer
Japanese aircraft models, the Zero continued to serve in a front-line role until
the end of the war in the Pacific. During the final phases, it was also adapted
for use in kamikaze operations. Japan produced more Zeros than any other model
of combat aircraft during the war.

With its low-wing cantilever monoplane layout, retractable, wide-set
conventional landing gear and enclosed cockpit, the Zero was one of the most
modern carrier based aircraft in the world at the time of its introduction. It
had a fairly high-lift, low-speed wing with very low wing loading. This,
combined with its light weight, resulted in a very low stalling speed of well
below 60 kn (110 km/h; 69 mph). This was the main reason for its phenomenal
maneuverability, allowing it to out-turn any Allied fighter of the time. Early
models were fitted with servo tabs on the ailerons after pilots complained that
control forces became too heavy at speeds above 300 kilometres per hour (190
mph). They were discontinued on later models after it was found that the
lightened control forces were causing pilots to overstress the wings during
vigorous maneuvers.

It has been claimed that the Zero's design showed a clear influence from British
and American fighter aircraft and components exported to Japan in the 1930s, and
in particular on the American side, the Vought V-143 fighter. Chance Vought had
sold the prototype for this aircraft and its plans to Japan in 1937. Eugene
Wilson, president of Vought, claimed that when shown a captured Zero in 1943, he
found that "There on the floor was the Vought V 142 [sic] or just the spitting
image of it, Japanese-made", while the "power-plant installation was distinctly
Chance Vought, the wheel stowage into the wing roots came from Northrop, and the
Japanese designers had even copied the Navy inspection stamp from Pratt &
Whitney type parts." While the sale of the V-143 was fully legal, Wilson later
acknowledged the conflicts of interest that can arise whenever military
technology is exported. Counterclaims maintain that there was no significant
relationship between the V-143 (which was an unsuccessful design that had been
rejected by the U.S. Army Air Corps and several export customers) and the Zero,
with only a superficial similarity in layout.

The Zero resembled the 1937 British Gloster F.5/34. Performance of the Gloster
F.5/34 was comparable to that of early model Zeros, with its dimensions and
appearance remarkably close to the Zero. Gloster had a relationship with the
Japanese between the wars, with Nakajima building the carrier-based plane, the
Gloster Gambet, under license. However allegations about the Zero being a copy
have been discredited by some authors.

Name

The A6M is usually known as the "Zero" from its Japanese Navy type designation,
Type 0 carrier fighter (Rei shiki Kanjo sentoki, ???????), taken from the last
digit of the Imperial year 2600 (1940) when it entered service. In Japan, it was
unofficially referred to as both Rei-sen and Zero-sen; Japanese pilots most
commonly called it Zero-sen, where sen is the first syllable of sentoki,
Japanese for "fighter plane".

In the official designation "A6M", the "A" signified a carrier-based fighter,
"6" meant that it was the sixth such model built for the Imperial Navy, and "M"
indicated Mitsubishi as the manufacturer.

The official Allied code name was "Zeke", in keeping with the practice of giving
male names to Japanese fighters, female names to bombers, bird names to gliders,
and tree names to trainers. "Zeke" was part of the first batch of "hillbilly"
code names assigned by Captain Frank T. McCoy of Nashville, Tennessee, (assigned
to the Allied Technical Air Intelligence Unit (ATAIU) at Eagle Farm Airport in
Australia), who wanted quick, distinctive, easy-to-remember names. The Allied
code for Japanese aircraft was introduced in 1942, and McCoy chose "Zeke" for
the "Zero". Later, two variants of the fighter received their own code names.
The Nakajima A6M2-N floatplane version of the Zero was called "Rufe", and the
A6M3-32 variant was initially called "Hap". General "Hap" Arnold, commander of
the USAAF, objected to that name, however, so it was changed to "Hamp".


Role
Fighter

National origin
Japan

Manufacturer
Mitsubishi Heavy Industries

First flight
1 April 1939

Introduction
1 July 1940

Retired
1945 (Japan)

Primary user
Imperial Japanese Navy Air Service

Produced
1939–1945

Number built
10,939

Variants
Nakajima A6M2-N

At the time of the attack on Pearl Harbor, 521 Zeros were active in the Pacific,
328 in first-line units. The carrier-borne Model 21 was the type encountered by
the Americans. Its tremendous range of over 2,600 kilometres (1,600 mi) allowed
it to range farther from its carrier than expected, appearing over distant
battlefronts and giving Allied commanders the impression that there were several
times as many Zeros as actually existed.

The Zero quickly gained a fearsome reputation. Thanks to a combination of
unsurpassed maneuverability — compared to contemporary Axis fighters — and
excellent firepower, it easily disposed of Allied aircraft sent against it in
the Pacific in 1941. It proved a difficult opponent even for the Supermarine
Spitfire. "The RAF pilots were trained in methods that were excellent against
German and Italian equipment but suicide against the acrobatic Japs", as Lt.Gen.
Claire Lee Chennault had to notice. Although not as fast as the British fighter,
the Mitsubishi fighter could out-turn the Spitfire with ease, sustain a climb at
a very steep angle, and stay in the air for three times as long.

Allied pilots soon developed tactics to cope with the Zero. Due to its extreme
agility, engaging a Zero in a traditional, turning dogfight was likely to be
fatal. It was better to swoop down from above in a high-speed pass, fire a quick
burst, then climb quickly back up to altitude. A short burst of fire from heavy
machine guns or cannon was often enough to bring down the fragile Zero. These
tactics were regularly employed by Grumman F4F Wildcat fighters during
Guadalcanal defense through high-altitude ambush, which was possible due to
early warning system consisted of Coas****chers and radar. Such "boom-and-zoom"
tactics were also successfully used in the China Burma India Theater (CBI) by
the "Flying Tigers" of the American Volunteer Group (AVG) against similarly
maneuverable Japanese Army aircraft such as the Nakajima Ki-27 Nate and Nakajima
Ki-43 Oscar. AVG pilots were trained by their commander Claire Chennault to
exploit the advantages of their P-40s, which were very sturdy, heavily armed,
generally faster in a dive and level flight at low altitude, with a good rate of
roll.

Another important maneuver was Lieutenant Commander John S. "Jimmy" Thach's
"Thach Weave", in which two fighters would fly about 60 m (200 ft) apart. If a
Zero latched onto the tail of one of the fighters, the two aircraft would turn
toward each other. If the Zero followed his original target through the turn, he
would come into a position to be fired on by the target's wingman. This tactic
was first used to good effect during the Battle of Midway and later over the
Solomon Islands.

Many highly experienced Japanese aviators were lost in combat, resulting in a
progressive decline in quality, which became a significant factor in Allied
successes. Unexpected heavy losses of pilots at the Battles of the Coral Sea and
Midway dealt the Japanese carrier air force a blow from which it never fully
recovered.

Throughout the Battle of Midway Allied pilots expressed a high level of
dissatisfaction with the Grumman F4F Wildcat. The Commanding Officer of USS
Yorktown noted:

The fighter pilots are very disappointed with the performance and length of
sustained fire power of the F4F-4 airplanes. The Zero fighters could easily
outmaneuver and out-climb the F4F-3, and the consensus of fighter pilot opinion
is that the F4F-4 is even more sluggish and slow than the F4F-3. It is also felt
that it was a mistake to put 6 guns on the F4F-4 and thus to reduce the rounds
per gun. Many of our fighters ran out of ammunition even before the Jap dive
bombers arrived over our forces; these were experienced pilots, not novices.

They were astounded by the Zero's superiority:

In the Coral Sea, they made all their approaches from the rear or high side and
did relatively little damage because of our armor. It also is desired to call
attention to the fact that there was an absence of the fancy stunting during
pull outs or approaches for attacks. In this battle, the Japs dove in, made the
attack and then immediately pulled out, taking advantage of their superior climb
and maneuverability. In attacking fighters, the Zeros usually attacked from
above rear at high speed and recovered by climbing vertically until they lost
some speed and then pulled on through to complete a small loop of high wing over
which placed them out of reach and in position for another attack. By reversing
the turn sharply after each attack the leader may get a shot at the enemy while
he is climbing away or head on into a scissor if the Jap turns to meet it.

In contrast, Allied fighters were designed with ruggedness and pilot protection
in mind. The Japanese ace Saburo Sakai described how the toughness of early
Grumman aircraft was a factor in preventing the Zero from attaining total
domination:

I had full confidence in my ability to destroy the Grumman and decided to finish
off the enemy fighter with only my 7.7 mm machine guns. I turned the 20mm cannon
switch to the 'off' position, and closed in. For some strange reason, even after
I had poured about five or six hundred rounds of ammunition directly into the
Grumman, the airplane did not fall, but kept on flying! I thought this very
odd—it had never happened before—and closed the distance between the two
airplanes until I could almost reach out and touch the Grumman. To my surprise,
the Grumman's rudder and tail were torn to shreds, looking like an old torn
piece of rag. With his plane in such condition, no wonder the pilot was unable
to continue fighting! A Zero which had taken that many bullets would have been a
ball of fire by now.

When the powerfully armed Lockheed P-38 Lightning, armed with four "light
barrel" AN/M2 .50 cal. Browning machine guns and one 20 mm autocannon, and the
Grumman F6F Hellcat and Vought F4U Corsair, each with six AN/M2 heavy calibre
Browning guns, appeared in the Pacific theater, the A6M, with its low-powered
engine and lighter armament, was hard-pressed to remain competitive. In combat
with an F6F or F4U, the only positive thing that could be said of the Zero at
this stage of the war was that, in the hands of a skillful pilot, it could
maneuver as well as most of its opponents. Nonetheless, in competent hands, the
Zero could still be deadly.

Due to shortages of high-powered aviation engines and problems with planned
successor models, the Zero remained in production until 1945, with over 10,000
of all variants produced.

American opinions

The American military discovered many of the A6M's unique attributes when they
recovered a largely intact specimen of an A6M2, the Akutan Zero, on Akutan
Island in the Aleutians. During an air raid over Dutch Harbor on June 4, 1942,
one A6M fighter was hit by ground-based anti-aircraft fire. Losing oil, Flight
Petty Officer Tadayoshi Koga attempted an emergency landing on Akutan Island
about 20 miles (32 km) northeast of Dutch Harbor, but his Zero flipped over on
soft ground in a sudden crash-landing. Koga died instantly of head injuries (his
neck was broken by the tremendous impact), but the relatively-undamaged fighter
was found over a month later by an American salvage team and was shipped to
Naval Air Station North Island, where testing flights of the repaired A6M
revealed both strengths and deficiencies in design and performance.

The experts who evaluated the captured Zero found that the plane weighed about
2,360 kg (5,200 lb) fully loaded, some 1,260 kg (2,780 lb) lighter than the F4F
Wildcat, the standard United States Navy fighter of the time. The A6M's airframe
was "built like a fine watch"; the Zero was constructed with flush rivets, and
even the guns were flush with the wings. The instrument panel was a "marvel of
simplicity ... with no superfluities to distract [the pilot]." What most
impressed the experts was that the Zero's fuselage and wings were constructed in
one piece, unlike the American method that built them separately and joined the
two parts together. The Japanese method was much slower, but resulted in a very
strong structure and improved close maneuverability.

American test pilots found that the Zero's controls were "very light" at 320
km/h (200 mph), but stiffened at faster speeds (above 348 km/h (216 mph)) to
safeguard against wing failure. The Zero could not keep up with Allied aircraft
in high-speed maneuvers, and its low "never exceed speed" (VNE) made it
vulnerable in a dive. While stable on the ground despite its light weight, the
aircraft was designed purely for the attack role, emphasizing long range,
maneuverability, and firepower at the expense of protection of its pilot. Most
lacked self-sealing tanks and armor plating.

British opinions

Captain Eric Brown, the Chief Naval Test Pilot of the Royal Navy, recalled being
impressed by the Zero during tests of captured aircraft. "I don't think I have
ever flown a fighter that could match the rate of turn of the Zero. The Zero had
ruled the roost totally and was the finest fighter in the world until mid-1943."

Specifications (A6M2 (Type 0 Model 21))

General characteristics
Crew: 1
Length: 9.06 m (29 ft 9 in)
Wingspan: 12 m (39 ft 4 in)
Height: 3.05 m (10 ft 0 in)
Wing area: 22.44 m2 (241.5 sq ft)
Aspect ratio: 6.4
Airfoil: root: MAC118 or NACA 2315; tip: MAC118 or NACA 3309
Empty weight: 1,680 kg (3,704 lb)
Gross weight: 2,796 kg (6,164 lb)
Max takeoff weight: 2,796 kg (6,164 lb)
Fuel capacity: 518 l (137 US gal; 114 imp gal) internal + 1x 330 l (87 US gal;
73 imp gal) drop tank
Powerplant: 1 × Nakajima NK1C Sakae-12 14-cylinder air-cooled radial piston
engine, 700 kW (940 hp) for take-off
710 kW (950 hp) at 4,200 m (13,800 ft)Propellers: 3-bladed Sumitomo-Hamilton
constant-speed propeller

Performance
Maximum speed: 533 km/h (331 mph, 288 kn) at 4,550 m (14,930 ft)
Cruise speed: 333 km/h (207 mph, 180 kn)
Never exceed speed: 600 km/h (370 mph, 320 kn)
Range: 1,870 km (1,160 mi, 1,010 nmi)
Ferry range: 3,102 km (1,927 mi, 1,675 nmi)
Service ceiling: 10,000 m (33,000 ft)
Rate of climb: 15.7 m/s (3,090 ft/min)
Time to altitude: 6,000 m (20,000 ft) in 7 minutes 27 seconds
Wing loading: 107.4 kg/m2 (22.0 lb/sq ft)
Power/mass: 0.294 kW/kg (0.179 hp/lb)

Armament

Guns:

2× 7.7 mm (0.303 in) Type 97 aircraft machine guns in the engine cowling, with
500 rounds per gun.
2× 20 mm (0.787 in) Type 99-1 Mk.3 cannon in the wings, with 60 rounds per gun.

Bombs:
2× 60 kg (130 lb) bombs or
1× fixed 250 kg (550 lb) bomb for kamikaze attacks




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