In 1936, the Imperial Japanese Navy Air Service issued a specification for a carrier based dive bomber to replace the Aichi D1A,[1] a two-seat biplane developed from the German Heinkel He 66.[2] The new dive bomber was to be a low-wing monoplane, with proposals submitted by Aichi, Mitsubishi and Nakajima. Orders were placed with Aichi and Nakajima for prototypes in 1934.[1] [3] Nakajima's design was based on its C3N and B5N that had been designed to meet 1935 requirements for a reconnaissance aircraft and torpedo bomber respectively, and like these aircraft, was a single-engined monoplane of all-metal construction with folding wings for storage aboard ship. It was powered by a single Nakajima Hikari nine-cylinder radial engine, rated at 660hp820hp, and driving a two-bladed variable-pitch propeller. It had a retractable tailwheel undercarriage, in which the mainwheels were designed to be lowered for use as dive brakes, although more conventional dive brakes were added as a result of a change in the specification.[1]
The first prototype made its maiden flight in 1937, with the second and third prototypes flying in 1939.[1] Aichi's AM-17 proved superior however, and was ordered into production as the Aichi D3A in December 1939.[1] [4]
The second prototype was retained by Nakajima and used as a testbed, helping in the development of the Nakajima Sakae and Homare engines, and remaining in use until 1945.[5]