The Aichi E16A Zuiun 'Paul' was a floatplane reconnaissance aircraft and dive bomber designed to replace the E13A 'Jake' on the cruisers and battleships of the Imperial Japanese Navy. Work on the next generation of floatplane reconnaissance aircraft began in 1939, before the E13A had even been accepted by the Japanese Navy. This 14-Shi specification called for a successor to the E13 generation of seaplanes then being tested, but was too vague to produce any designs. In October 1940, just before the E13A was accepted by the Navy, Aichi began work on a private venture design, with the designation AM-22. In January 1941 the Navy gave their approval to this design by producing a new 16-Shi specification based around the AM-22. The specification was changed once more, in July 1941, and then remained constant.
The prototype E16A was completed in May 1942. It was of all metal construction, with a stressed skin surface (apart from a wooden tailplane, wooden wingtips and fabric covered control surfaces). It was powered by a 1,300hp Mitsubishi MK8A Kinsei 51 radial engine, 220hp more powerful than the engine used in the E13A. The new aircraft was smaller and lighter than the E13A, with higher top and cruising speeds and a range of 1,491 miles, 200 miles better than the older aircraft.
The prototype was armed with three 7.7mm machine guns – two fixed guns in the wings, and one flexible gun in the rear cockpit. In production aircraft the wing guns were replaced with 20mm cannon. The wings folded up to allow it to be used on smaller cruisers and seaplane tenders. The twin floats were carried on vertical N struts, and carried the hydraulically operated dive brakes. The first prototype had a wingspan of 41ft 8in, but two further aircraft were produced with 42ft wide wings, which became standard on the production aircraft. These later prototypes also carried the 20mm cannon.
The E16A1 was accepted by the Navy in August 1943 as the Navy Reconnaissance Seaplane Zuiun (Auspicious Cloud) Model 11 (Type numbers having been abandoned for security reasons). Early production aircraft used the same Kinsei 51 engine as the prototype, which was later replaced by the Kinsei 53.
By the time the E16A1 Zuiun entered service in 1944 the Allies had gained air superiority over most of the Pacific. It was produced in much smaller numbers than the E13A – only 256 were built including the four prototypes. Of these 193 were built by Aichi between January 1944 and May 1945, and 59 by Nippon Hikoki K.K. at Tomiakoa, between August 1944 and August 1945.
The E16A1 Zuiun was used extensively against the American invasion of the Philippines during 1944, suffering heavily losses. Many of the surviving aircraft were used for kamikaze attacks during the invasion of Okinawa.
One prototype of a E16A2 was produced in 1944. This was powered by a Kinsei 62 engine, which provided 1,560hp at take-off and 1,190hp at 19,030ft. The prototype was still undergoing tests at the end of the war.
Engine: Mitsubishi MK8D Kinsei 54 14 cylinder radial
Power: 1,300hp at take-off, 1,200hp at 9,845ft, 1,100hp at 20,340ft
Wing span: 42ft
Length: 35ft 6in
Height: 15ft 8in
Weights: 10,052lb maximum
Max Speed: 273mph at 18,040ft
Cruising Speed: 207mph at 16,405ft
Service Ceiling: 32,810ft
Range: 1,491 miles
Armament: Two 20mm cannon in wings, one 13mm machine gun in rear cockpit
Bomb-load: 551lb of bombs, carried externally