The first prototype of the
Type 90-2 Reconnaissance Seaplane, or
E4N1, inspired by the
Vought O2U Corsair, flew in 1930. This was fitted with twin floats and had no
cowling for the engine. This
prototype was rejected as not being very maneuverable. The plane was redesigned as the
Type 90-2-2 or
E4N2, with a single main-float and twin, wing-mounted outriggers, powered by a cowled Nakajima Kotobuki 2-kai-I nine-cylinder air-cooled radial engine. This entered production for the
Navy in 1931. In December 1941 a more durable version was produced, the Type 90-2-2 (E4N2), and a wheeled version was introduced as the Type 90-2-3 (E4N3). A carrier version with wheels and arrestor gear, the E4N2-C, was trialed by 5 aircraft but ultimately not accepted for use. Between 1931 and 1936 Nakajima produced 80 E4Ns aircraft and Kawanishi produced 67 between 1932 and 1934. Nine aircraft were converted to night mail use in 1933, with one cockpit enclosed to hold mail and deliver it between the main islands of Japan. E4N2s took part in the
January 28 incident between China and Japan. The aircraft was gradually replaced by the
Nakajima E8N. ==Variants==