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The Mitsubishi A7M ''Reppū'' (烈風, "Strong Wind") was designed as the successor to the
Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...
's
A6M Zero The Mitsubishi A6M "Zero" is a long-range carrier-based aircraft, carrier-based fighter aircraft formerly manufactured by Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and was operated by the Imperial Japanese Navy from 19 ...
, with development beginning in 1942. Performance objectives were to achieve superior speed, climb, diving, and armament over the Zero, as well as better maneuverability. To meet these performance specifications its size and weight were significantly greater than its predecessor. The A7M's allied codename was "Sam".


Design and development

Towards the end of 1940, the
Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...
asked Mitsubishi to start design on a carrier-based fighter, to meet specification ''16-Shi'' (a designation under a system using
regnal year A regnal year is a year of the reign of a sovereign, from the Latin ''regnum'' meaning kingdom, rule. Regnal years considered the date as an ordinal, not a cardinal number. For example, a monarch could have a first year of rule, a second year of ...
s that indicated "1941" – the year in which the specification was formally issued). The fighter would be the successor to the carrier-based Zero. At that time, however, there were no viable high-output, compact engines to use for a new fighter. In addition,
Jiro Horikoshi was the chief engineer of many Japanese fighter designs of World War II, including the Mitsubishi A6M Zero fighter. Early life Jiro Horikoshi was born near the city of Fujioka, Gunma Prefecture, Japan, in 1903. Horikoshi graduated from the new ...
's team was preoccupied with addressing early production issues with the A6M2b as well as starting development on the A6M3 and the 14-''Shi'' interceptor (which would later become the Mitsubishi J2M Raiden, a land-based
interceptor Interceptor may refer to: Vehicles * Interceptor aircraft (or simply "interceptor"), a type of point defense fighter aircraft designed specifically to intercept and destroy enemy aircraft * Ford Crown Victoria Police Interceptor, a police car * ...
built to counter high-altitude
bombers A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped from an aircraf ...
). As a result, work on the Zero successor was halted in January 1941. In April 1942, the development of the A6M3 and the 14-''Shi'' interceptor was complete, and the Japanese Navy once again tasked Mitsubishi and Horikoshi's team with designing a new Zero successor to become the Navy Experimental 17-shi Ko (A) Type Carrier Fighter Reppu. In July 1942 the Navy issued specifications for the fighter: it had to fly faster than above , climb to in less than 6 minutes, be armed with two 20 mm cannon and two machine guns, and retain the maneuverability of the A6M3. As before, one of the main hurdles was engine selection. To meet the specifications the engine would need to produce at least , which narrowed choices down to Nakajima's NK9 ( Ha-45/Homare), or Mitsubishi's MK9 ( Ha-43); both engines still being under development. These engines were based on 14-cylinder ( Nakajima ''Sakae'' and Mitsubishi ''Kinsei'', respectively) engines converted to 18-cylinder powerplants. The early NK9 had less output but was already approved by the Navy for use on the
Yokosuka P1Y The Yokosuka P1Y ''Ginga'' (銀河, "Galaxy") was a twin-engine, land-based bomber developed for the Japanese Imperial Navy in World War II. It was the successor to the Mitsubishi G4M and given the Allied reporting name "Frances". Design and d ...
''Ginga'', while the larger MK9 promised more horsepower. With the larger, more powerful engine, wing loading became an issue. The Navy requested at most 150 kg/m2, but wanted 130 kg/m2 which complicated design considerations further. With the NK9 it could achieve 150 kg/m2, but with the less power it would not meet the specifications for maximum speed. With the MK9 the engineers concluded it could fulfill the requirements; however, production of the MK9 was delayed compared to the NK9, and the Japanese Navy instructed Mitsubishi to use the NK9. Work on the 17-''Shi'' was further delayed by factories prioritizing A6M and
Mitsubishi G4M The Mitsubishi G4M was a twin-engine, land-based medium bomber formerly manufactured by the Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and operated by the Imperial Japanese Navy from 1940 to 1945. Its official designat ...
production as well as further work on A6M variants and addressing ''Raiden'' issues. As a result, the 17-''Shi'', which became the A7M1, officially flew for the first time on 6 May 1944, four years after development started. The aircraft demonstrated excellent handling and maneuverability, but was underpowered as Mitsubishi engineers feared, and with a top speed similar to the A6M5 Zero. It was a disappointment, and the Navy ordered development to stop on 30 July 1944, but Mitsubishi obtained permission for development to continue using the Ha-43 engine, flying with the completed Ha-43 on 13 October 1944. The A7M2 now achieved a top speed of , while climb and other areas of performance surpassed the Zero, leading the Navy to change its mind and adopt the craft. The A7M2 was also equipped with automatic combat flaps, used earlier on the
Kawanishi N1K-J The Kawanishi N1K ''Kyōfū'' (, "Strong Wind", Allied reporting name "Rex") is an Imperial Japanese Navy floatplane fighter. The Kawanishi N1K-J ''Shiden'' (, "Violet Lightning") was an Imperial Japanese Navy Air Service land-based version ...
, significantly improving maneuverability. In June 1945, ace pilot
Saburō Sakai was a Japanese naval aviator and flying ace (''"Gekitsui-O"'', ) of the Imperial Japanese Navy during World War II. Sakai had 28–64 aerial victories, including shared ones, according to official Japanese records, but his autobiography, ''Samura ...
was ordered to Nagoya to test the prototype. He was favorably impressed.


Variants

; A7M1 ''Reppū'' :First prototype powered by a
Nakajima Homare The Nakajima Homare (誉, "praise" or, more usually, "honour") was an air-cooled twin-row 18 cylinder radial Japanese aircraft engine manufactured during World War II. Producing almost 2,000 horsepower, it was used widely by both the Imperial J ...
22 engine, with a maximum speed of 574 km/h (356 mph). The armament consisted of two 13.2 mm (.52 in) Type 3 machine guns and two 20 mm (.80 in) Type 99 cannons in the wings. While featuring excellent manoeuvrability, the A7M1's Homare engine left it underpowered which resulted in its cancellation. Eight built. ; A7M2 ''Reppū'' :Revised version powered by a
Mitsubishi Ha-43 The Mitsubishi Ha-43, known as the Ha-211 by the Imperial Japanese Army Air Force (IJAAF) and MK9 by the Imperial Japanese Navy Air Service (IJNAS)), was a Japanese 18-cylinder, twin-row air-cooled radial engine developed during World War II. ...
engine, with a maximum speed of 627 km/h (389 mph). Armament the same as previous model, or four 20 mm (.80 in) Type 99 cannons. The A7M2 was to be the main production aircraft of the A7M series. Three were converted from A7M1. One massproduction type under assembling at the end of the war. ; A7M3 ''Reppū'' :Proposed land-based fighter version powered by a mechanically driven three-speed supercharged
Mitsubishi Ha-43 The Mitsubishi Ha-43, known as the Ha-211 by the Imperial Japanese Army Air Force (IJAAF) and MK9 by the Imperial Japanese Navy Air Service (IJNAS)), was a Japanese 18-cylinder, twin-row air-cooled radial engine developed during World War II. ...
engine, with a maximum speed of 642 km/h (398 mph). The armament consisted of six 20 mm (.80 in) Type 99 cannons in the wings. Prototype under construction but was incomplete prior to end of war. ; A7M3-J ''Reppū-Kai'' :Proposed land-based interceptor version powered by a turbo-supercharged
Mitsubishi Ha-43 The Mitsubishi Ha-43, known as the Ha-211 by the Imperial Japanese Army Air Force (IJAAF) and MK9 by the Imperial Japanese Navy Air Service (IJNAS)), was a Japanese 18-cylinder, twin-row air-cooled radial engine developed during World War II. ...
engine including an inter-cooler, with a maximum speed of 648 km/h (402 mph). The armament consisted of six 30 mm (1.20 in) Type 5 cannons, four wing-mounted & two oblique fuselage-mounted. Full-scale mock-up built, but no prototype.


Production

* Production was disrupted by an earthquake on 7 December 1944 in the
Nagoya is the largest city in the Chūbu region, the fourth-most populous city and third most populous urban area in Japan, with a population of 2.3million in 2020. Located on the Pacific coast in central Honshu, it is the capital and the most pop ...
region, and Allied bombing raids on 11 March 1945, which caused the loss of full scale drawings and jigs for the A7M2 and Ki-83.USSBS, 1947, p. 76 This ceased the development of the A7M2 and the plane would never see combat.


Specifications (A7M2)


See also


Footnotes


Bibliography

* Angelucci, Enzo. ''The Rand McNally Encyclopedia of Military Aircraft, 1914–1980''. San Diego, California: The Military Press, 1983. . * * Green, William. ''Warplanes of the Second World War, Volume Three: Fighters''. London: Macdonald & Co. (Publishers) Ltd., 1961 (seventh impression 1973). .


External links

{{Allied reporting names Carrier-based aircraft A7M, Mitsubishi A7M A7M, Mitsubishi Single-engined tractor aircraft Aircraft first flown in 1944