The D1A emerged from the Imperial Japanese Navy’s requirement for a sophisticated carrier-based dive bomber.
In late 1934, the IJN commissioned the completion of the Aichi AB-9 design, which resulted in the early model D1A1.
Contrary to common belief, the D1A1 was not designed by Aichi Tokei Denki Kabushiki Kaisha, but by Ernst Heinkel Flugzeugwerke upon Aichi’s request.
The initial Heinkel design was the He 50, a float-equipped variant of the landing gear model.
This led to the He 66, which Aichi promptly started producing as the D1A1.
The D1A’s design, derived from the Heinkel He 66—a He 50 export version—featured a metal biplane structure with fabric covering, fixed landing gear, and a conventional tail skid.
Initially, models were equipped with 365 kW (490 hp) engines, and it was only in later versions that more potent 433 kW (580 hp) engines were incorporated.
The D1A saw primary use in the Second Sino-Japanese War and continued service until Japan’s entry into World War II in 1941.
With the onset of the Pacific War, all remaining D1A1s were decommissioned, and most D1A2s were withdrawn from frontline service to training roles.
A total of 68 D1A2s served as secondary support until their retirement in 1942.
Specifications
Crew
2
Length
9.3 m (30 ft 6 in)
Wingspan
11.4 m (37 ft 5 in)
Height
3.41 m (11 ft 2 in)
Wing area
34.7 m2 (374 sq ft)
Empty weight
1,516 kg (3,342 lb)
Gross weight
2,500 kg (5,512 lb)
Max take-off weight
2,610 kg (5,754 lb)
Powerplant
1 × Nakajima Hikari 1,
9-cylinder air cooled radial piston engine
540 kW (730 hp) for take-off
500 kW (670 hp) at 3,500 m (11,500 ft)
Propellers
2 bladed metal propellers
Performance
Maximum speed
309 km/h (192 mph, 167 kn) at 3,200 m (10,500 ft)
Cruise speed
222 km/h (138 mph, 120 kn) at 1,000 m (3,300 ft)
Range
926 km (575 mi, 500 nmi)
Service ceiling
6,980 m (22,900 ft)
Time to altitude
3,000 m (9,800 ft) in 7 minutes, 51 seconds
Armament
Guns
2 × fixed 7.7 mm (.303 in) Type 92 machine guns
&
1 × flexible 7.7 mm (.303 in) Type 92 machine gun
Bombs
1 × 250 kg (551 lb) bomb under fuselage
&
2 × 30 kg (66 lb) bombs under wings.
Sources Japanese Aircraft 1910–1941-R C Mikesh & A Shorzoe.
The Xplanes of Imperial Japanese Army & Navy 1924-1945-Illustrated Warplane History.
Japanese Aircraft of the Pacific War-Rene Francillon.
Japanese Imperial Army Navy Aircraft Color Markings-Koku Fan 42.
Japanese Military Aircraft Illustrated-Bunrindo No. 711.
Japanese WW2 Aircraft in Colour Volume 1-Martin Ferkl.
