World War II: Mitsubishi A6M Zero

Zero leaving for Pearl Harbor
A Japanese Navy "Zero" fighter (tail code A1-108) takes off from the aircraft carrier Akagi, on its way to attack Pearl Harbor during the morning of 7 December 1941. National Archives & Records Administration

Most people hear the word "Mitsubishi" and think automobiles. But the company was actually established as a shipping firm in 1870 in Osaka Japan, and it quickly diversified. One of its businesses, Mitsubishi Aircraft Company, founded in 1928, would go on to build lethal fighter planes for the Imperial Japanese Navy during World War II. One of those planes was the A6M Zero Fighter.

Design & Development

The design of the A6M Zero began in May 1937, shortly after the introduction of the Mitsubishi A5M fighter. The Imperial Japanese Army had commissioned Mitsubishi and Nakajima both to build the planes, and the two companies began preliminary design work on a new carrier-based fighter while waiting to receive the final requirements for the aircraft from the army. These were issued in October and were based upon the A5M's performance in the ongoing Sino-Japanese conflicts. The final specifications called for the aircraft to possess two 7.7 mm machine guns, as well as two 20 mm cannon.

In addition, each airplane was to have a radio direction finder for navigation and a full radio set. For performance, the Imperial Japanese Navy required that the new design be capable of 310 mph at 13,000 ft. and possess an endurance of two hours at normal power and six to eight hours at cruising speed (with drop tanks). As the aircraft was to be carrier-based, its wingspan was limited to 39 ft. (12m). Stunned by the navy's requirements, Nakajima pulled out of the project, believing that such an aircraft could not be designed. At Mitsubishi, the company's chief designer, Jiro Horikoshi, began toying with potential designs.

After initial testing, Horikoshi determined that the Imperial Japanese Navy's requirements could be met, but that the aircraft would have to be extremely light. Utilizing a new, top-secret aluminum, T-7178, he created an aircraft that sacrificed protection in favor of weight and speed. As a result, the new design lacked armor to protect the pilot, as well as the self-sealing fuel tanks that were becoming standard on military aircraft. Possessing retractable landing gear and a low-wing monoplane design, the new A6M was one of the most modern fighters in the world when it completed testing. 

Specifications

Entering service in 1940, the A6M became known as the Zero based on its official designation of Type 0 Carrier Fighter. A quick and nimble aircraft, it was a few inches under 30 feet in length, with a wingspan of 39.5 feet, and a height of 10 feet. Other than its armaments, it held only one crew member, the pilot, who was the sole operator of the 2 × 7.7 mm (0.303 in) Type 97 machine gun. It was outfitted with two 66-lb. and one 132-lb. combat-style bombs, and two fixed 550-lb. Kamikaze-style bombs. It had a range of 1,929 miles, a maximum speed of 331 mph, and could fly as high as 33,000 feet.

Operational History

In early 1940, the first A6M2, Model 11 Zeros arrived in China and quickly proved themselves as the best fighter in the conflict. Fitted with a 950 hp Nakajima Sakae 12 engine, the Zero swept Chinese opposition from the skies. With the new engine, the aircraft exceeded its design specifications and a new version with folding wingtips, the A6M2, Model 21, was pushed into production for carrier use.

For much of World War II, the Model 21 was the version of the Zero that was encountered by Allied aviators. A superior dogfighter than the early Allied fighters, the Zero was able to out-maneuver its opposition. To combat this, Allied pilots developed specific tactics for dealing with the aircraft. These included the "Thach Weave," which required two Allied pilots working in tandem, and the "Boom-and-Zoom," which saw Allied pilots fighting on the dive or climb. In both cases, the Allies benefited from the Zero's complete lack of protection, as a single burst of fire was generally enough to down the aircraft.

This contrasted with Allied fighters, such as the P-40 Warhawk and F4F Wildcat, which, though less maneuverable, were extremely rugged and difficult to bring down. Nevertheless, the Zero was responsible for destroying at least 1,550 American aircraft between 1941 and 1945. Never substantially updated or replaced, the Zero remained the Imperial Japanese Navy's primary fighter throughout the war. With the arrival of new Allied fighters, such as the F6F Hellcat and F4U Corsair, the Zero was quickly eclipsed. Faced with superior opposition and a dwindling supply of trained pilots, the Zero saw its kill ratio drop from 1:1 to over 1:10.

During the course of the war, over 11,000 A6M Zeros were produced. While Japan was the only nation to employ the aircraft on a large scale, several captured Zeros were used by the newly-proclaimed Republic of Indonesia during the Indonesian National Revolution (1945-1949).