The first prototype of the Type 90-2 Reconnaissance Seaplane, or E4N1, flew in 1930. This was fitted with twin floats and had no cowling for the engine. This prototype was rejected.
The type was completely redesigned as the Type 90-2-2 or E4N2, with a single main-float and twin, wing-mounted outriggers and introduced a cowled engine. This entered production for the Navy in 1931.
A landplane version of the Type 90-2-2 was developed as the E4N2-C with a tailwheelundercarriage
In 1933, nine E4N2-C airframes were converted to P1mail planes. Single-seat landplanes with an enclosed cockpit, these were employed on night-mail services between the Japanese Home Islands.
Variants
E4N1
(Navy Type 90-2-1 Reconnaissance Seaplane) twin-float seaplane, Nakajima NZ - two prototypes only.[1]
1 X as second letter is for experimental aircraft or imported technology demonstrators not intended for service,
2 Hyphenated trailing letter (-J, -K, -L, -N or -S) denotes design modified for secondary role, 3 Possibly incorrect designation, but used in many sources