Kawanishi H8K - Design and Development

Design and Development

At the same time the type's predecessor, the Kawanishi H6K, was going into service in 1938 the Navy ordered the development of a larger, longer-ranged patrol aircraft under the designation Navy Experimental 13-Shi Large-size Flying Boat. The result was a large, shoulder-winged design that is widely regarded as the best flying boat of the war. Despite this, initial development was troublesome, with the prototype displaying terrible handling on the water. Deepening of the hull, redesigning of the planing bottom and the addition of spray strips under the nose rectified this Two further prototypes — actually pre-production aircraft — joined the development program in December 1941.

The IJNAF accepted the first production version as the H8K1, Navy Type 2 Flying Boat, Model 11, of which 14 would be built.

The improved H8K2 variant soon appeared, and its extremely heavy defensive armament earned it deep respect among Allied aircrews. The H8K2 was an upgrade over the H8K1, having more powerful engines, slightly revised armament, and an increase in fuel capacity. This was to be the definitive variant, with 112 produced.

36 examples of a dedicated transport version, the H8K2-L, were also built, capable of carrying 62 troops. This aircraft was also known as Seiku (晴空, "Clear Sky"). The side defensive blisters, ventral defensive hatch, and dorsal turret were discarded. To increase the available space within the aircraft, its hull tanks were removed, thus reducing its range.