| A7M Reppū | |
|---|---|
| |
| A Mitsubishi A7M2 Reppū in a hangar, c. 1945 | |
| Role | Carrier-based fighter
Type of aircraft
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| National origin | Japan |
| Manufacturer | Mitsubishi Heavy Industries |
| First flight | 6 May 1944 |
| Retired | 1945 |
| Status | Retired |
| Primary user | Imperial Japanese Navy Air Service |
| Number built | 9 |
The Mitsubishi A7M Reppū (烈風, "Strong Wind") was designed as the successor to the Imperial Japanese Navy's A6M Zero, with development beginning in 1942. Performance objectives were to achieve superior speed, climb, diving, and armament over the Zero, as well as better maneuverability – all parameters that were ultimately achieved towards the end of its development in 1945. However, limitations on Japanese industry towards the end of the war prevented the A7M from ever entering mass production or being deployed for active duty, and it never saw active service. Its Allied reporting name was "Sam".
Towards the end of 1940, the Imperial Japanese Navy asked Mitsubishi to start design on a carrier-based fighter, to meet specification 16-Shi (adesignation under a system using regnal years 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'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 built to counter high-altitude bombers). 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 345 kn (639 km/h; 397 mph) above 6,000 m (20,000 ft), climb to 6,000 m (20,000 ft) in less than 6 minutes, be armed with two 20 mm cannon and two 13 mm (0.51 in) 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 2,000 hp (1,500 kW), 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 Ginga bomber, 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 medium bomber 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.[1] 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 628 km/h (339 kn; 390 mph), while climb and other areas of performance surpassed the Zero, leading the Navy to change its mind and adopt the craft.[2] The A7M2 was also equipped with automatic combat flaps, used earlier on the Kawanishi N1K-J, significantly improving maneuverability.[citation needed]
In June 1945, ace pilot Saburō Sakai was ordered to test the prototype at Nagoya. He was favorably impressed.[3]
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| Year | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Jan. | Feb. | Mar. | Apr. | May | June | July | Aug. | Sept. | Oct. | Nov. | Dec. | Annual | |
| 1944 | 1 | 1 | 2 | 2 | 2 | 0 | 0 | 0 | 0 | 8 | |||
| 1945 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | ||||
| Total | 9 |
The USSBS Report identifies nine aircraft (two A7M1 prototypes, seven A7M2 prototypes and service trials aircraft)[4] while Francillon notes the same two A7M1 prototypes, seven A7M2 prototypes and service trials aircraft, but with one A7M2 final production build for a total of 10.[6]
Data from Japanese Aircraft of the Pacific War[7]
General characteristics
Performance
Armament
Related development
Aircraft of comparable role, configuration, and era
Related lists
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Mitsubishi aircraft
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| Imperial Japanese Army short designations |
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| Imperial Japanese Navy short designations |
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| Japanese Self-Defense Force designations |
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| Fighters (A) |
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| Torpedo bombers (B) |
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| Shipboard reconnaissance (C) |
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| Dive bombers (D) |
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| Reconnaissance seaplanes (E) |
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| Observation seaplanes (F) |
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| Land-based bombers (G) |
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| Flying Boats (H) |
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| Land-based Fighters (J) |
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| Trainers (K) |
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| Transports (L) |
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| Special-purpose (M)1 |
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| Floatplane fighters (N) |
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| Land-based bombers (P) |
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| Patrol (Q) |
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| Land-based reconnaissance (R) |
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| Night fighters (S) |
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1 X as second letter is for experimental aircraft or imported technology demonstrators not intended for service, 2 Hyphenated trailing letter (-J, -K, -L, -N or -S) denotes design modified for secondary role, 3 Possibly incorrect designation, but used in many sources | |
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Imperial Japanese Navy official aircraft names
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| Fighters |
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| Heavy bombers4 |
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| Bombers5 |
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| Patrol6 |
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| Reconnaissance7 |
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| Trainers8 |
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| Transports9 |
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| Miscellaneous10 |
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| Special-purpose aircraft11 |
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With some exceptions for rockets, jets and repurposed aircraft, names chosen were for: 1. Winds, 2. Lightning, 3. Nighttime lights, 4. Mountains, 5. Stars/constellations, 6. Seas, 7. Clouds, 8. Plants, 9. Skies, 10. Landscapes, and 11. Flowers. Published translations disagree, and many are simplified, especially for plants, where the Japanese referred to a specific variety and the common translations only to the broader type. | |||||||||
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| Aircraft in Japanese service |
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| Foreign aircraft thought to be in Japanese service |
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