The Aichi E3A1 Navy Type 90-1 Reconnaissance Seaplane (HD 56) was a Heinkel-designed single engined ship-borne reconnaissance aircraft that was produced in small numbers in Japan by Aichi.
In 1928 the Japanese Navy asked Aichi and Nakajima to produce designs for shipboard catapult-launched reconnaissance aircraft. Aichi turned to their German partners Heinkel for a suitable design, and were provided with the HD 56. The HD 56 was a single-engined twin-float biplane, with a crew of two. The HD 56 was powered by a Wright Whirlwind engine. The aircraft used mixed wood and metal construction. The wings were linked by interplane struts with no bracing wires.
Nakajima produced a similar design, which was given the designation Type 90-2 Reconnaissance Seaplane, while Yokosho and Kawanishi co-operated on the Type 90-3 Reconnaissance Seaplane.
The Japanese Navy liked the overall design of the HD 56, but wanted an increase in speed and in range. Aichi produced a modified version of the aircraft. The 200hp Wright Whirlwind was replaced with a 300hp Type 90 Tempu engine. Top speed rose from 104mph to 123mph. The wing span was reduced by nearly two feet, the interplane struts were removed and the wings moved closer together. The modified aircraft's endurance increased from four and a half hours up to six hours.
The first of the new Aichi built aircraft made its maiden flight in August 1931. A total of twelve were built, and accepted for service as the E3A1 Navy Type 90-1 Reconnaissance Seaplane. The Nakajima aircraft also entered service, and was rather more successful.
The E3A1 served on Jintsu -class light cruisers and saw some combat early in the Sino-Japanese War. After a short front-line career they were withdrawn and used for training. Others were used for catapult launching tests.
Engine: Type 90 Gasuden Tempu nine-cylinder radial air cooled engine
Span: 36ft 5in
Length: 27ft 8.75in
Empty weight: 2,464lb
Loaded weight: 3,527lb
Max speed: 123mph at sea level
Climb Rate: 18min 18sec to 9,843ft
Service ceiling: 15,452ft
Endurance: 6 hours
Armament: One fixed forward firing 7.7mm machine gun, one flexibly mounted dorsal 7.7mm machine gun
Bomb load: Two 66lb bombs