The E11A was planned to a 1936 requirement for a successor to the same company’s E10A as the noctur-nal spotter carried by Japanese battleships and cruis¬ers, and first flew in June 1937. The Aichi prototype was evaluated competitively against the Kawanishi El1K, and ordered into production during April 1938 with the full designation Navy Type 98 Night Recon¬naissance Seaplane, and the short designation E11A1 (reconnaissance seaplane, 11th in series, built by Aichi, 1st model). Including prototypes, production up to 1940 amounted to just 17 aircraft, and these saw limited operational service in the opening rounds of Japan’s Pacific campaign in the Second World War.
Of biplane configuration, the two-step hull carried a braced tail unit, with the tail-plane and elevator mounted almost halfway up the fin. Accommodation was provided for a crew of three, and there was an open bow position that could be used during on-water manoeuvres, or mounting a defensive machine gun. Balancer floats were mounted beneath each lower wing, close to the wingtip. The engine was a Hiro Type 91 Model 22 inline engine, mounted at the centre-section of the upper wing, and driving a pusher propeller with spinner.

E11A1
Engine: 1 x Hiro Type 91 Model 11 inline piston, 620-hp (462-kW)
Maximum speed: 135 mph (217 kph) at 7,875 ft (2,400 m)
Climb to 9,845 ft (3,000 m): 18 min 32 sec
Service ceiling: 14,520 ft (4,425 m)
Range: 1,209 miles (1,945 km)
Weight empty: 4,248 lb (1,927 kg)
Maximum take-off weight: 7,275 lb (3,300 kg)
Wing span: 47 ft 6.5 in (14.49 m)
Length: 35 ft 1.75 in (l0.7lm)
Height: 18ft 0.5 in (5.50m)
Armament: one 7.7-mm (0.303-in) machine-gun

In 1934, based on experience of testing the Experimental 6-Shi Night Reconnaissance Flying boat, the Imperial Japanese Navy drew up a specification for a new night reconnaissance aircraft, intended to shadow enemy fleets during the cover of darkness, with orders being placed with Aichi and with Kawanishi.

Aichi’s design, with the company designation AB-12, was a single-engined biplane flying boat of all-metal construction. Its two-bay wings folded rearwards to save space on board ship, while its crew of three were accommodated in an enclosed cabin. It was powered by a pusher water-cooled Aichi Type 91 engine, driving a four-blade wooden propeller.

The first prototype flew in December 1934, and when tested proved to have superior stability to the competing Kawanishi E10K, and so was ordered into production.

The AB-12 entered service in August 1936 with the Japanese Navy as the Type 96 Night Reconnaissance Seaplane, with the short designation E10A. The allied code name ‘Hank’ was assigned before its appearance or manufacturer was known.

Fifteen aircraft were built for the Imperial Japanese Navy serving from 1936, remaining in service until 1941, being phased out in 1941 before the Japanese attack on Pearl Harbour.

E10A
Powerplant: × Aichi Type 91 W-12, 370 kW (500 hp) to 485 kW (650 hp)
Propeller: 4-bladed wooden fixed-pitch pusher
Wingspan: 15.5 m (50 ft 10 in)
Wing area: 52.1 m2 (561 sq ft)
Length: 11.219 m (36 ft 10 in)
Height: 4.5 m (14 ft 9 in)
Empty weight: 2,100 kg (4,630 lb)
Gross weight: 3,300 kg (7,275 lb)
Wing loading: 63.2 kg/m2 (12.9 lb/sq ft)
Power/mass: 0.113 kW/kg (0.069 hp/lb)
Maximum speed: 206 km/h (128 mph, 111 kn) at sea level
Cruise speed: 106 km/h (66 mph, 57 kn) at 1,000 m (3,281 ft)
Range: 1,852 km (1,151 mi, 1,000 nmi)
Service ceiling: 4,120 m (13,520 ft)
Time 3,000 m (9,843 ft): 17 minutes 42 seconds
Guns: 1× 7.7 mm machine gun flexibly mounted in nose
Crew: 3