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Aichi AB-5 / E7A / AB-6

In 1932, the Imperial Japanese Navy raised a specification for a long range floatplane reconnaissance aircraft to replace its Yokosuka E1Y and E5Y operating from its seaplane tenders and battleships, requesting prototypes from Aichi and Kawanishi.

Aichi’s entry, the Aichi AB-6(E7A) or Aichi Experimental 7-Shi Reconnaissance Seaplane, designed by Tetsuo Miki, was based on the Heinkel He 62, one example of which had been imported by Aichi the previous year for evaluation against a similar requirement.

The AB-6 was a biplane with folding wings for storage aboard ship, of all-metal construction with fabric covering, and powered by a single Hiro Type 91 W12 engine.

Its crew of three, pilot, observer and radio operator/gunner were accommodated in an enclosed cockpit.

The prototype was completed in February 1933 and made its maiden flight from Nagoya harbor.

 While it had good handling in the air, its speed, take-off, and landing performance was disappointing, and the aircraft was modified to try to improve matters.

It was fitted with revised wings, of different aerofoil section and with full-span leading edge slats.

The original Hamilton Standard two bladed metal variable pitch propeller was first replaced by a two bladed wooden propeller and then a four bladed wooden unit.

Despite these changes, Kawanishi’s design remained superior, and in 1934, was ordered into production as the Navy Type 94 Reconnaissance Seaplane, or Kawanishi E7K.





10.44 m (34 ft 3 in)


12.98 m (42 ft 7 in)


4.80 m (15 ft 9 in)

Wing area

40.61 m2 (437.1 sq ft)

Empty weight

1,920 kg (4,233 lb)

Gross weight

3,020 kg (6,658 lb)

Max take-off weight

3,300 kg (7,275 lb)


1 × Hiro Type 91, water cooled W12 engine,

470 kW (630 hp)


Maximum speed

230 km/h (140 mph, 120 kn) at sea level

Cruise speed

150 km/h (92 mph, 80 kn) at 1,000 m (3,300 ft)

Stall speed

81 km/h (50 mph, 44 kn)


11.9 h

Service ceiling

4,850 m (15,910 ft)

Time to altitude

3,000 m (9,840 ft) in 14 min 54 s



1× fixed forward firing 7.7 mm machine gun


1 flexibly mounted in rear cockpit and 1 × under fuselage.


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