The Kawanishi H8K was conceived as a replacement for the Japanese Navy venerable and obsolete H6K maritime reconnaissance and bombing platform. The H6K was the only standardized flying boat in operations when Japan attacked Pearl Harbor in December 1941. But it would be only a matter of time before a new, more powerful replacement took its place.
Just over a year after the 6K achieved operational status, the Japanese Navy began planning for its replacement. The requirements were simple enough. An increase of 50% in its original operational range coupled with a 30% increase in speed, would give the new aircraft a performance profile similar to that of the British Short Sunderland. It is remarkable that after only a ten month design and developmental stage, Japanese engineers were able to produce one of the finest military aircraft ever constructed.
Armed with up to five 0.78in cannons, four machine guns and well armed crew cabinets, the 8K was indeed a remarkable flying machine. The 8K first took to the air in the winter of 1940 and after several modifications made to the hull structure (initially the airplane?s narrow hull caused uncontrollable proposing in the water when lifting nose in the water?s surface); the aircraft went into production mode in the summer of 1941. A total of 175 8Ks were produce in three different variants. They were the original 8K1, the advance 8K2 with heavier armament and a new radar system, and the 3H8K2-L, which was a strictly transport version with two passenger decks.
The 8K made its combat debut on the night of March 4th 1942 when a formation of them attempted to bomb the island of Oahu, Hawaii. Bad weather over the target area disturbed the raid. Nevertheless, the complete voyaged proved the aircraft?s worth to the Navy.
Four Mitsubishi 1850hp Kasei radial engines
Wingspan 124 ft.
Length 92 ft.
Height 30 ft.
Total Wing Area 1722 sq ft.
Weight 40454 lb (empty)
71530 lb (fully loaded)
Operational Ceiling 28 740 ft.
Range 4460 miles
Climb Rate 1575 ft. per minute
Top Speed 290 mph
0.78in bow, dorsal and tail cannons fitted in powered turrets. Four 0.303in heavy machine guns located in cockpit, side and ventral hatches.