On this day in aviation history, 84 years ago (December 5, 1941), the Kawanishi E15K Shiun took flight for the first time. Japanese for Violet Cloud, the Shiun was a reconnaissance floatplane used in the Second World War by the Imperial Japanese Navy. The Allies referred to the E15K as the Norm, after Squadron Leader Norman O. Clappison of the Royal Australian Air Force and a member of the Technical Air Intelligence Unit.
The Shuin’s story begins in 1939, when the Imperial Japanese Navy requested that the Kawanishi Aircraft Company design a reconnaissance floatplane. The aircraft was to have two seats, high-speed, and an 800 nautical mile range. Additionally, the floatplane needed a high level of performance in order to evade interception by land-based fighters. The IJN’s intent was to have this new reconnaissance seaplane operate from a new class of battle cruisers being developed, which would be flagships for groups of submarines. The IJN ordered the first of this new class of cruisers, the Ōyodo, in 1939, as well.
The Kawanishi E15K was powered by a Mitsubishi MK4S Kasei 24 14-cylinder radial engine, rated at 1,850 horsepower for take-off (1,680 at 6,900 feet). The aircraft had a crew of two, a range of 1,820 nautical miles, and a service ceiling of 32,350 feet. The Shiun’s maximum airspeed was 291 mph, and cruise was typically 184. For self-defense, the E15K was armed with a single 7.7 millimeter Type 92 machine gun in the rear cockpit.
During the testing period of the Shiun, issues were encountered with the aircraft’s retractable stabilizing floats. This led to accidents while landing, when the floats could not be properly lowered. Eventually, the float system was abandoned, and the aircraft would be ordered into limited production. Officially titled the Navy Type 2 High-speed Reconnaissance Seaplane Shiun Model 11, the E15K would not enter service until April 30, 1944. In combat, the aircraft’s float jettison proved faulty, and the aircraft’s production was capped at fifteen total in February of 1944.
