Kawanishi E15K1
Hidroavión japonés de reconocimiento
Japanese reconnaissance floatplane

Prototipo en tierra.
Prototype on land.

Prototipo en pruebas.
Prototype in tests.

Aparato de producción en serie.
Series production aircraft.

En 1939 la Marina Japonesa solicitó a Kawanishi el desarrollo de un hidroavión con prestaciones superiores a los cazas enemigos basados en tierra. Las especificaciones 14-Shi no fueron muy exigentes lo que permitió a Kawanishi el diseño de un avión que supuso un avance significativo para su tiempo. Pese a ser aparentemente simples, los requisitos de la Marina eran difíciles de cumplir por lo que los diseñadores se decidieron por un sistema de flotadores poco usual. El flotador central podía desprenderse en caso de emergencia permitiendo un incremento en la velocidad de 58 millas por hora. Los flotadores estabilizadores se construyeron con un fondo metálico y cuerpo de goma de manera que pudiesen ser inflados al extenderlos. En despegue los flotadores estaban extendidos, pero si el flotador central era desprendido, se plegaban para funcionar como boyas que permitieran al aparato amerizar. El motor original era un Mitsubishi MK4D Kasei 14 de 1.500 caballos con dos hélices de doble pala que giraban en sentido contrario, las primeras que se instalaron en un aparato de fabricación japonesa.

El proyecto, llamado K-10 se inició en julio de 1939 pero por dificultades técnicas no pudo ser completado hasta finales de 1941. El prototipo E15K1 voló por vez primera vez en diciembre de aquel año. Aunque las características de vuelo era satisfactorias, surgieron problemas con el mecanismo de retracción de los flotadores y el sistema de giro de las hélices. En octubre de 1942 el aparato fue entregado a la Marina para realizar más pruebas pero los problemas con los flotadores persistieron y el sistema de inflado fue eliminado.

Pese a estas dificultades la Marina decidió poner el aparato en producción limitada con la denominación oficial de Hidroavión Rápido de Reconocimiento Shiun (Nube Violeta) Modelo 11. Los poco fiables flotadores estabilizadores fueron finalmente reemplazados por otros fijos. El incremento de resistencia se compensó en parte con la adopción de un motor Mitsubishi MK4S Kasei 24 de 1.850 caballos con escapes individuales.

Seis E15K1, denominados Norm por los Aliados, se enviaron a Palau para probarlos en combate, pero fueron rápidamente derribados por los cazas enemigos al no poder lanzar el flotador central por defectos en su mecanismo. Con flotador el aparato resultaba excesivamente lento y su única ametralladora de 7’7 mm, su escasa capacidad de combustible y de protección lo hacían muy vulnerable. La producción terminó en febrero de 1944 con sólo 15 Shiuns construidos incluyendo el prototipo.

In 1939 Kawanishi was instructed by the Japanese Navy to develop a floatplane to out-perform Allied land-based fighters. The 14-Shi specifications were very open which allowed Kawanishi to design an aircraft that was a significant advance by its time. The Navy requirement, simple as it seemed, was difficult to meet and the designers adopted an unusual float system. The central float could be detached in an emergency thus allowing to increase the speed in 58 mph. The stabilizing floats were fitted with metal bottoms and rubberized-fabric tops so that they could be inflated when the floats were extended. These floats were extended in normal take-offs but if the central float was jettisoned, the they were kept retracted to act as flotation buoys. The powerplant consisted of a 1,500 hp Mitsubishi MK4D Kasei 14 driving a pair of two-blade contra-rotating propellers, the first of their kind to be used in a Japanese-built aircraft.

The design, called K-10, started in July 1939, but a series of technical difficulties delayed the completion until late 1941, the prototype E15K1 finally making its maiden flight in December that year. Although flying characteristics were satisfactory, problems arose with the floats retraction mechanism and the pitch control of the contra-rotating propellers. In October 1942 the aircraft was handed over to the Navy for more flight tests but the problems with the floats continued and the inflation system was eliminated.

The Navy decided to put the aircraft in limited production under the official designation Navy High-speed Reconnaissance Seaplane Shiun (Violet Cloud) Model 11. The original unreliable stabilizing floats were replaced by fixed units attached to the wings by slim cantilever struts. The added drag was compensated by an increase in power by the use of a 1,850 hp Mitsubishi MK4S Kasei 24 with individual exhaust stacks.

Six E15K1s, nicknamed Norm by the Allies, were sent to Palau for combat tests, but they were quickly wiped out by Allied fighters as the central float jettisoning system failed to operate. With the float attached the aircraft was too slow and its single 7.7 mm machine-gun, the lack of fuel tankage and armour protection made it vulnerable to enemy fire. Production was finished in February 1944 and only 15 Shiuns, prototype included, were built.

In 1939 Kawanishi was instructed by the Japanese Navy to develop a floatplane to out-perform Allied land-based fighters. The 14-Shi specifications were very open which allowed Kawanishi to design an aircraft that was a significant advance by its time. The Navy requirement, simple as it seemed, was difficult to meet and the designers adopted an unusual float system. The central float could be detached in an emergency thus allowing to increase the speed in 58 mph. The stabilizing floats were fitted with metal bottoms and rubberized-fabric tops so that they could be inflated when the floats were extended. These floats were extended in normal take-offs but if the central float was jettisoned, the they were kept retracted to act as flotation buoys. The powerplant consisted of a 1,500 hp Mitsubishi MK4D Kasei 14 driving a pair of two-blade contra-rotating propellers, the first of their kind to be used in a Japanese-built aircraft.

The design, called K-10, started in July 1939, but a series of technical difficulties delayed the completion until late 1941, the prototype E15K1 finally making its maiden flight in December that year. Although flying characteristics were satisfactory, problems arose with the floats retraction mechanism and the pitch control of the contra-rotating propellers. In October 1942 the aircraft was handed over to the Navy for more flight tests but the problems with the floats continued and the inflation system was eliminated.

The Navy decided to put the aircraft in limited production under the official designation Navy High-speed Reconnaissance Seaplane Shiun (Violet Cloud) Model 11. The original unreliable stabilizing floats were replaced by fixed units attached to the wings by slim cantilever struts. The added drag was compensated by an increase in power by the use of a 1,850 hp Mitsubishi MK4S Kasei 24 with individual exhaust stacks.

Six E15K1s, nicknamed Norm by the Allies, were sent to Palau for combat tests, but they were quickly wiped out by Allied fighters as the central float jettisoning system failed to operate. With the float attached the aircraft was too slow and its single 7.7 mm machine-gun, the lack of fuel tankage and armour protection made it vulnerable to enemy fire. Production was finished in February 1944 and only 15 Shiuns, prototype included, were built.

FUENTES Y REFERENCIA - SOURCES & REFERENCE

René J. Francillon, Japanese Aircraft of the Pacific War, Putnam & Company, 1970.