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Imperial Japanese Navy Air Arm

A piloted Japanese version of the German V-1 rocket, this suicide plane, called "Baku" (stupid) by American forces in the Pacific, was first used in March, 1945. It was launched from a bomber twenty to thirty miles from the target. Alternately gliding and using its rockets, it was flown by its pilot in a shallow dive against a warship. It carried a 2,250-lb. warhead in its nose.

The first attempt to create an air arm was made by the Imperial Japanese Navy in June 1912 when the Naval Aeronautical Research Committee was established and six officers were sent to France and the United States to learn to fly and maintain aircraft. When in France, one of these officers, First Lieutenant Yozo Kaneko, placed the first Japanese naval order for heavier-than-air machines: two Farman floatplanes. Soon thereafter his colleagues in the United States ordered two Curtiss seaplanes. On November 2, 1912 these aircraft made their first flight in Japan from the newly created naval air station on the Oppama Coast near Yokosuka.

Domestic training of additional naval pilots proceeded slowly thereafter and was impaired by the limited budget allocated to the fledgeling air arm of the Imperial Japanese Navy. However, in July 1913 this Service took delivery of their first aircraft built in Japan - a modified Farman floatplane built at the Yokosuka Naval Arsenal - and in November 1913 placed in service their first seaplane tender, the Wakamiya Maru, a converted cargoship. When on August 23, 1914 Japan declared war against Germany in accordance with the provision of the AngloJapanese Alliance Agreement, the Imperial Japanese Navy had twenty pilots and ten seaplanes. Immediately upon Japan's entry into the war, four of these aircraft -one Farman three-seat seaplane and three Farman two-seat seaplanes-sailed for Kiaochow Bay in China aboard the Wakamiya Maru for operation against the German fortress at Tsingtao. In less than two months these four aircraft made 49 sorties, logging a total of 71 flight hours, during which they flew reconnaissance missions and dropped 199 bombs, sinking a small German mine-layer.

Despite this modest but promising debut the Japanese naval air arm experienced only nominal growth during the First World War whilst the air arm of France, the United Kingdom, the United States and Germany became a major weapon in the arsenal of these nations. In March 1915 the first fatal air accident in which two naval officers were killed in the crash of a Maurice Farman seaplane dampened the interest of the Imperial Japanese Navy for their air arm. However, the growing importance of aviation in the war on the European continent led to the creation in Japan of the first two Naval Air Corps, the Yokosuka Kokutai in April 1916 and the Sasebo Kokutai in March 1918. In 1917 the first operational naval aircraft designed and built in Japan by First Lieutenant Chikuhei Nakajima - who later was to found Nakajima Hikoki K.K. (Nakajima Aeroplane Co., Ltd.) - was manufactured at the Yokosuka Naval Arsenal. But most of the Japanese naval aircraft were still imported in limited numbers from the United Kingdom and France.

The end of the war led to a further slowdown in the development of Japanese naval aviation. The most notable event of this period was the first successful take-off from a deck mounted on the Wakamiya Maru which was made in June 1920 by an imported Sopwith Pup flown by Lieutenant Kuwabara. However, in September 1921 the Imperial Japanese Navy began the second phase in the development of their air arm when the British Aviation Mission led by the Master of Sempill arrived in Japan with 28 technicians and instructors and some 105 modern fighters, bombers, trainers and flying-boats. At the same time a number of British-designed aircraft were placed in production in Japan, whilst Herbert Smith, former Chief Designer of Sopwith Aviation Co., joined the Mitsubishi firm to design a series of carrier-borne aircraft.

In November 1921, the Hosho, the world's first aircraft carrier built as such, was launched. In early 1923 the first take-offs and landings were made aboard the Hosho and the Imperial Japanese Navy began to take delivery of three types of carrier-borne aircraft designed by Herbert Smith for Mitsubishi: the Navy Type 10 Carrier Fighter (128 built), the Navy Type 10 Carrier Reconnaissance Plane (159 built) and the Navy Type 10 Carrier Torpedo Bomber (20 built). With the availability of these aircraft and with the help received from the British Aviation Mission the Imperial Japanese Navy were able to build up an efficient air arm.

Powered by a 450 h.p. Napier Lion, the Navy Type 10 Carrier Torpedo Bomber (Type 10 indicated that the aircraft had been ordered during the tenth year of Taisho, i.e. 1921 A.D.) - the Imperial Japanese Navy's first carrier-borne bomber - proved only moderately successful as its triplane wood-and-fabric construction could not withstand the rigours of carrier operations at sea. Consequently, less than two years after the first flight of this aircraft, Herbert Smith designed for Mitsubishi a new Napier Lion-powered biplane which was originally designated 2MT1. Completed in 1923, the Mitsubishi 2MT1 - later redesignated B1M1 - was placed in production the following year as the Navy Type 13 Carrier Attack Bomber Model 1 and 197 aircraft of this type were built. These were followed by 116 slightly modified aircraft designated 2MT5 or B1M2 and by 490 machines of the 3MT2 (B1M3) version which were powered by a 600 h.p. Japanese-built Hispano engine and were three-seaters, whereas both B1M1 and B1M2 were two-seaters.

The next major type of carrier-borne torpedo bomber adopted by the Imperial Japanese Navy resulted from a 1928 competition between Mitsubishi, Nakajima, Aichi and Kawanishi. As Herbert Smith had returned to England, Mitsubishi asked Blackburn Aircraft, Ltd. to design the aircraft. Powered by a 600 h.p. Hispano engine, the first prototype - bearing the Mitsubishi's designation 3MR4 - was actually built in England and arrived in Japan in February 1930. Modified prototypes featuring redesigned tail surfaces and Handley Page slots on the upper wing leading edge were built in Japan and the aircraft was placed in production in 1932 as the Navy Type 89 Carrier Attack Bomber. Including prototypes 204 Type 89 were built in two versions, the B2M1 and B2M2 which could be identified by the different shape of their tail surfaces and wing tips but neither version proved satisfactory because of inadequate flight performances and engine troubles.

Due to the poor showing of the Navy Type 89 Carrier Attack Bomber the Imperial Japanese Navy was forced to keep in service the older Mitsubishi B1M3 whilst the Dai-Ichi Kaigun Gijitsusho (First Naval Air Technical Arsenal) designed their Yokosuka B3Y1. Powered by a 600 h.p. Hire Type 91 engine, the first B3Y1 was completed in 1932 and was placed in production by both Aichi and the Dai-Ichi Kaigun Gijitsusho as the Navy Type 92 Carrier Attack Bomber. Disappointing performances led to a combined production run of only 130 aircraft.

By 1934 the Imperial Japanese Navy had still not taken delivery of a satisfactory torpedo bomber since the Mitsubishi B1M3 had first been introduced in their inventory. Realizing that the development of a modern torpedo bomber of monoplane design - a feature which was finally recognized as mandatory - would require a long time, the Imperial Japanese Navy instructed its Dai-Ichi Kaigun Gijitsusho, Mitsubishi Jukogyo K.K., and Nakajima Hikoki K.K. to develop an interim aircraft to a 9-Shi specification. The aircraft designed by the Dai-Ichi Kaigun Gijitsusho, which made use of the efficient biplane wings of the Kawanishi E7K1 reconnaissance float seaplane, won the competition and was placed in production by Nakajima, Mitsubishi and the Dai Juichi Kaigun Kokusho (llth Naval Air Arsenal) at Hiro. Powered by a 840 h.p. Nakajima Hikari 2 and designated Navy Type 96 Carrier Attack Bomber (Yokosuka B4Y1) two hundred aircraft of this type were built. The Navy Type 96 Carrier Attack Bomber saw extensive service during the Second SinoJapanese Conflict but had been relegated to second line duties by the time the Pacific War started.

Already in the early twenties the Japanese carrier force was able to deploy efficient fighter and torpedo bomber units but deployment of dive bomber units did not materialize until 1934. Prototypes of carrierborne dive bombers had been submitted by the DaiIchi Kaigun Gijitsusho (Yokosuka) and Nakajima Hikoki K.K. in answer to a 6-Shi specification and again by Nakajima Hikoki K.K. in compliance to a 7-Shi specification. However, none of these 1931 and 1932 programmes proved satisfactory enough to justify quantity production and the Imperial Japanese Navy had to issue in 1933 an 8-Shi specification calling for two-seat dive bombers and emphasizing structural strength and manoeuvrability. The Aichi's entry in this competition, which bore the constructor's designation AB-9, was based on the German-3esigned Heinkel He 66 biplane. Powered by a 580 h.p. Nakajima Kotobuki 2 Kai 1 radial, the Aichi AB-9 won the competition and, designated Navy Type 94 Carrier Bomber (Aichi D1A1), became the first type of dive bomber to be accepted by the Japanese Navy. Two years later an improved version of the aircraft powered by a 660 h.p. Nakajima Hikari 1 was accepted as the Navy Type 96 Carrier Bomber (Aichi D1A2). Both versions performed well in the war against China but had been replaced in front line units by the Navy Type 99 Carrier Bomber Model 11 (Aichi D3A1) when Japan launched their attack against the Allies.

The development of land-based bombers was equally neglected by the Imperial Japanese Navy and until the advent of the Mitsubishi G3M1 of World War II fame only two types of aircraft in this class had been built in limited numbers for that Service. The first to be accepted was the Navy Type 93 Attack Bomber (Mitsubishi G1M1), a twin-engined biplane with open cockpits, of which only eleven were built in 1932 and 1933. They were succeeded by eight Navy Type 95 Attack Bomber (Hiro G2H1) built between 1933 and 1936. Powered by two 1,180 h.p. Hiro Type 94 in-line engines, the Hiro G2H1 was a monoplane with troussered undercarriage and twin fins and rudders but its performances and reliability left much to be desired. Consequently, the Navy Type 95 Attack Bomber saw only limited use in its intended role and was used as cargo transport during the Second Sino-Japanese Conflict.

The need to develop a land-based bomber capable of co-operating with the fleet far out at sea was recognized in early 1933 by Rear Adm. Isoroku Yamamoto, then Chief of the Technical Division of the Naval Bureau of Aeronautics. As the development of such an aircraft would strain the capability of the fledgeling Japanese aircraft industry, Adm. Yamamoto suggested that Mitsubishi Jukogyo K.K. be awarded a contract to design and build a prototype solely intended as an experimental aircraft to be used for developing the technique of reliable long-range overwater operations. Accordingly, a special 8-Shi specification calling for a twin-engined, long-range reconnaissance aircraft and purposely avoiding any mention of specific military requirements was issued to Mitsubishi on a non-competitive basis.

In answer to this specification Sueo Honjo, assisted by Tomio Kubo and Nobuhiko Kusabake, designed the Mitsubishi Ka-9. This aircraft featured an exceptionally clean airframe with twin fins and rudders and mid-mounted Junkers "double wings". Powered by two 500 h.p. Hiro Type 91 in-line engines, the sole Ka-9 built made its first flight in April 1934 and soon demonstrated its exceptional flight endurance by flying some 3,760 miles and, as its handling characteristics were as pleasant as its performances were spectacular, the aircraft was enthusiastically received by the Imperial Japanese Navy.

The Kamikaze Pilot

Like Hitler's V-weapons, the Japanese kamikaze attacks were a desperate effort to compensate for a growing lack of air power. They were Japan's last stand in the air war. The kamikaze pilots, in single or twin-engine aircraft loaded with explosives, literally flew into Allied vessels in the hope that the resulting explosion would put the ships out of action. And they took a heavy toll - in the American Navy alone 35 vessels sunk and 288 damaged. The cost to Japan has been estimated at anywhere between 1,000 and 4,000 planes and pilots.

Combat Planes of World War Two Series 1 American Fighters, Volume One 2 German Air Force Fighters, Volume One 3 RAF Bombers, Volume One 4 German Air Force Bombers, Volume One 5 RAF Bombers, Volume Two 6 Japanese Navy Bombers 7 German Air Force Fighters, Volume Two 8 RAF Fighters, Volume One 9 German Air Force Bombers, Volume Two 10 American Fighters, Volume Two 11 French Fighters 12 American Bombers, Volume One

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