Mitsubishi A6M Reisen Zeke Vol. I

The need to develop purpose-built aircraft to operate from decks of new carriers soon became apparent. However, the Japanese aircraft manufacturers had little experience in design of carrier-based machines, so drawing from foreign experience became the only option. A breakthrough in the history of IJN naval aviation was arrival in April 1921 of the Sempill Mission which comprised a team of thirty naval aviation experts. It wasn’t the first time that the British lent their expertise to Japanese aviation. A year earlier a group of British Short Brothers engineers accepted the invitation of the IJN to help in mastering manufacturing techniques of the Felixstowe F.5 flying boat. The Sempill Mission brought with them modern combat aircraft and trainers, including the Avro 504K, Gloster Sparrowhawk, Sopwith Cuckoo, Parnall Panther, Blackburn Swift, S.E.5A, De Havilland D.H.9, a Short seaplane, as well as Supermarine Channel and Short Felixstowe F.5 flying boats. The Sempill Mission instructors help modernize IJN flight and ground crew training and produced a blueprint of the Japanese naval air arm’s organizational structure. The establishment of a Temporary Naval Flight Training Troop, led by Rear Admiral Tadaji Tajiri and staffed by British instructors, was also a British idea. The unit operated out of Kasumigaura (land-based aircraft) and Yokosuka (seaplanes and flying boats).
The British instructors remained in Japan for 18 months and trained Japanese aircrews in air navigation, reconnaissance operations, torpedo bombing and aerial photography, laying solid foundations for the future of the Japanese naval air arm. Initially all flight training was performed using British aircraft, but those were soon replaced with indigenous license-built machines. Nakajima obtained a license to build Avro 504K/L trainers, while Aichi acquired the manufacturing rights for the Felixtowe F.5 flying boat, which was also manufactured at Hiro and Yokosho Arsenals. At the same time Mitsubishi approached the British Sopwith Aircraft Co. seeking help in designing aircraft for Hosho air wing. Soon a team of Sopwith engineers, led by Herbert Smith, arrived in Japan to work on the project. Other Japanese aircraft manufacturers were also actively looking for foreign partners: Nakajima enlisted help of French firms Breguet and Nieuport, while Kawanishi cooperated with the British Short. Kawasaki invited experts from Germany, who were more than happy to accept employment overseas when the Treaty of Versailles greatly limited their earning potential at home. As can be clearly seen, the Japanese weren’t shy seeking foreign assistance in the development of their own naval air arm. However, while the Japanese manufacturers had little difficulty adopting modern airframe construction technologies imported from Europe, they struggled with powerplants. Most of the contemporary Japanese designs were powered by Lorraine, Hispano-Suiza or Napier engines. To move forward in that department required time.
Head of Mitsubishi, Koyota Iwasaki, understood that the development of modern naval aircraft wouldn’t be possible without foreign expertise and the only nation that seemed to have the necessary know-how was Great Britain. In early 1921 he invited Sopwith’s Herbert Smith, whose resume included the design of such excellent aircraft as the Camel and the Pup, to visit Mitsubishi’s new plant in Nagoya. Smith’s arrival may have had something to do with the fact that in 1920 Sopwith Aviation Company struggled financially and went bankrupt in short order. Those developments left Smith and his team unemployed, so the timing of the Japanese invitation couldn’t have been better. The Japanese paid much more generously than what Smith’s team could have hoped for back home, but the task ahead was also formidable. A team of seven British engineers was expected to design all types of aircraft (fighter, reconnaissance platform and a torpedo bomber) to be included in the Hosho air wing. Those would be the world’s first purpose-built carrier-based aircraft. The aircraft in service with the Royal Navy were simply land-based designs adapted to carrier operations. Also, at that time, Japan had no tender system in place and government contracts were simply granted to one of the aircraft manufacturers. That was a reflection of a weakness of Japanese aircraft manufacturing sector. Later on the government introduced a system requiring a publication of tactical and technical requirements (Shi), which led to a number of designs developed by different companies competing for the contract.

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The British team designed the 1MF fighter and 1MR reconnaissance aircraft, which were both approved for full-scale production, but the 1MT torpedo bomber was a complete flop.
It might be worthwhile at this point to take a closer look at Japanese aircraft industry, whose beginnings were rather unimpressive. Inter-service rivalry and lack of cooperation between the Imperial Japanese Navy and Army resulted in squandering of limited resources amidst attempts by both services to create their own, independent air arms. Not surprisingly, it did little to help the fledgling industry to grow. Contradictory requirements received by the industry led to the development of a multitude of aircraft types, all suffering from various shortcomings. It wasn’t until two major industrial players – Mitsubishi and Kawasaki – entered the arena that development of aircraft manufacturing base began to pick up pace. Also significant was the founding of Nakajima (future leader of aircraft industry) by Mitsui.