Mitsubishi Ki-2

The Mitsubishi Ki-2 (九三式双軽爆撃機) was a light bomber built by Mitsubishi for the Imperial Japanese Army in the 1930s. Its Allied nickname was "Louise". Despite its antiquated appearance, the Ki-2 was successfully used in Manchukuo and in north China during the early stages of the Second Sino-Japanese War, in areas where danger from enemy fighter aircraft was minimal. It was later used in a training role.

Design and development
The Ki-2 was a low-wing cantilever monoplane with corrugated metal alloy decking and twin fins and rudders, and had fixed divided landing gear. It was powered by two 435 kW Nakajima Kotobuki radial engines. Maximum speed was 225 km/h, normal range 900 km and maximum take-off weight 4550 kg. Single 7.7 mm (.303 in) machine guns were mounted in a semi-enclosed nose gun turret and a dorsal position, and maximum bomb load was 500 kg.

The Ki-2 was, like its stable mate the Mitsubishi Ki-1, an adaptation of the Junkers S36 first flown in 1927. Militarized into the Junkers K37 by Junker's Swedish subsidiary AB Flygindustri at Limhamn near Malmö in Sweden, it was able to reach altitudes not reachable for the fighter aircraft of 1927. However, as soon as 1930 this advantage was lost due to British developments such as the Bristol Bulldog fighter, and Junkers was not successful in selling the design. However, in 1931, representatives of the Mitsubishi Nainenki K.K. in Japan visited the Limhamn facilities to study some of the military conversions of Junkers aircraft, and purchased the sole K37 prototype S-AABP (ex D-1252 S36-prototype) as well as all development papers and a signed a contract for licensed production.

The K37 prototype was brought to Japan and tested in combat in the Manchurian Incident of 1931, following which the Imperial Japanese Army Air Force authorized Mitsubishi to produce both heavy and light bomber variations. The heavy bomber version, the Ki-1, was much larger than the original Junkers K37 and first flew in August 1932.

The light bomber version, the Mitsubishi Ki-2, was about the same size and weight as the K37 prototype. It flew for the first time in May 1933. While the fuselage was redesigned by Mitsubishi, the wings were kept largely unchanged, except for additional ailerons. Mitsubishi built total of 113 aircraft and an additional 13 aircraft built by Kawasaki Kōkūki Kōgyō KK from 1933-1936.

Operational history
The Mitsubishi Ki-2 was initially designated "Army Type 93-1 Twin-engine Light Bomber" under the former Japanese military aircraft nomenclature system. Although already obsolescent by the time of its introduction, it was used with great success in the counterinsurgency operations of the Pacification of Manchukuo, and as well as limited use in the Second Sino-Japanese War in combat in north China.

The Ki-2 was followed in production by an improved version designated the Mitsubishi Ki-2-ll, or "Army Type 93-2 Twin-engine Light Bomber," in 1936. The Ki-2-ll had a fully enclosed manually operated nose turret, an enclosed cockpit for the pilot, and semi-retractable main landing gear, which retracted forward into the engine nacelles. The Ki-2-ll also had new 559 kW Mitsubishi Ha-8 radial engines giving much improved overall performance with maximum speed increased to 283 km/h. Mitsubishi built a total of 61 Ki-2-II aircraft.

Vulnerable to attack by enemy fighters, and replaced by aircraft with greater range and payload by the late-1930s, both versions ended their flying careers in the training role. A civilian version of the Ki-2-ll named Otori (Phoenix) was bought by the Asahi Shimbun newspaper and made a number of long-range record-breaking and "goodwill" flights from 1936 to 1939. Registered J-BAAE, it covered the 4930 km from Tachikawa military air base to Bangkok in 21 hours 36 minutes flying time in December 1936, and in early 1939 achieved a round-China flight of some 9300 km.

Variants

 * Ki-2-I (Army Type 93-1 Twin-engined Light Bomber)
 * Initial production variant, 126 built.


 * Ki-2-II (Army Type 93-2 Twin-engined Light Bomber)
 * Final production variant with nose turret and semi-retractable main landing gear, 61 built.


 * Mitsubishi Ohtori
 * de-militarized long-range record-breaking aircraft operated by Asahi Shimbun newspaper. 1 built

Operators

 * Imperial Japanese Army Air Force
 * Asahi Shimbun
 * Asahi Shimbun