The Yokosho E6Y Type 19 Reconnaissance Seaplane was the first submarine-based reconnaissance plane to be officially accepted by the Japanese Navy.
Yokosho's first submarine launchable aircraft, the 1-go Reconnaissance Seaplane, had been produced in 1925-27, and undergone successful tests on the submarine I-21 in 1927-28. It was a cantilever wing biplane based on the Heinkel U 1. After these tests, work on the U-1 came to an end.
In 1929 the Yokosho design team, led by Jiro Saha and Tamefumi Suzuki, began work on the 2-go Reconnaissance Seaplane, this time loosely based on the British Parnall Peto reconnaissance seaplane. This was rather bigger than the 1-go, but had been successfully tested on the British submarine HMS M2.
The first version of the 2-go used the same Armstrong Siddeley Mongoose engine as the Parnall Peto, and was very similar in configuration. It was a twin-float single engine biplane. The fuselage had a metal framework with fabric covering, while the wings used a wooden framework and fabric covering. The wings and floats could be removed for storage in a small hanger on the submarine.
Yokosho built two prototypes, both powered by the Mongoose engine. The single 2-go was produced in 1929 and the single 2-go-kai in 1931. The 2-go was used for successful launch tests in May 1928, when it was catapulted off the submarine I-51.
In 1932 the 2-go was accepted for production as the Type 91 Reconnaissance Seaplane E6Y1. Eight production aircraft were built by Kawanishi in 1932-34, with the company designation Type N. The Type 91 used a slightly more powerful 130-160hp Gasuden Jimpu seven cylinder radial engine. Visually the V-struts of the 2-go were replaced by N-struts.
Engine: Gasuden Jimpu seven cylinder radial engine
Span: 26ft 3in
Length: 21ft 11.5in
Height: 9ft 5in
Empty weight: 1,256lb
Maximum take-off weight: 1,653lb
Max speed: 104.7mph
Climb Rate: 20min 14sec to 9,843ft