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.

Called "extra super duralumin", it was lighter, stronger and more ductile than other alloys used at the time but was prone to corrosive attack, which made it brittle.

No armour protection was provided for the pilot, engine or other critical points of the aircraft, and self-sealing fuel tanks, which were becoming common among other combatants, were not used.

[11] 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.

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).

[Note 2][13] 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 RAF pilots were trained in methods that were excellent against German and Italian equipment but suicide against the acrobatic Japs", as Lieutenant General Claire Lee Chennault noted.

[21] Although not as fast as the British fighter, the Zero 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.

A short burst of fire from heavy machine guns or cannon was often enough to destroy the Zero, provided that some hits rupture the fuel tanks.

These tactics were regularly employed by Grumman F4F Wildcat fighters during Guadalcanal defense through high-altitude ambush, which was possible with an early warning system consisting of coastwatchers and radar.

AVG pilots were trained by their commander Claire Chennault to exploit the advantages of their P-40 Warhawks, which were very sturdy, heavily armed, generally faster in a dive, and level flight at low altitude, with a good rate of roll.

Many highly experienced Japanese aviators were lost in combat, resulting in a progressive decline in pilot 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.

Captain Elliott Buckmaster, commanding officer of USS Yorktown notes: The fighter pilots are very disappointed with the performance and length of sustained fire power of the F4F-4 airplanes.

Because of shortages of high-powered aviation engines and problems with planned successor models, namely the superior Mitsubishi A7M2 Reppū, the Zero remained in production until 1945, with over 10,000 of all variants produced.

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 his wingmen hoped he had survived and so he went against Japanese doctrine to destroy disabled Zeros.

[33] 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.

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.

[33] 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.

By September, it had already been accepted for Navy testing as the A6M1 Type 0 Carrier Fighter, with the only notable change being a switch to a three-bladed propeller to cure a vibration problem.

On the downside, turning and range, which were the strengths of the Model 21, suffered due to smaller ailerons, decreased lift and greater fuel consumption.

However, "A6M4" does appear in a translation of a captured Japanese memo from a Naval Air Technical Arsenal, titled Quarterly Report on Research Experiments, dated 1 October 1942.

[41] The design and testing of the turbo-supercharger was the responsibility of the First Naval Air [Technical] Arsenal (第一海軍航空廠, Dai Ichi Kaigun Kōkūshō) at Yokosuka.

Lack of suitable alloys for use in the manufacture of a turbo-supercharger and its related ducting caused numerous ruptures, resulting in fires and poor performance.

[74][75] During preliminary testing, its performance was considered unsatisfactory due to the additional engine power failing to materialize and the unreliability of the fuel injection system.

It was designed to meet a requirement by the Navy for a dedicated attack/dive bomber version that could operate from smaller aircraft carriers[9] or according to another source, replace the obsolete Aichi D3A.

This included a reinforced vertical stabilizer, a special bomb rack, provision of two 350-litre drop tanks and fixed bomb/rocket swing stoppers on the underside of the wings.

The carburetor intake was much larger, a long duct like that on the Nakajima B6N Tenzan was added, and a large spinner — like that on the Yokosuka D4Y Suisei with the Kinsei 62 — was mounted.

In addition, the Model 64 was modified to carry two 150 L (40 US gal) drop tanks on either wing in order to permit the mounting of a 250 kg (550 lb) bomb on the underside of the fuselage.