Aichi (along with Nakajima and Mitsubishi) submitted their monoplane design designed by a team under Tokuhishiro Goake to a 1936 Japanese Navy specification (11-Shi) for a carrier-based dive-bomber to replace the aging D1A biplane series. Only Aichi's and Nakajima's submissions were pressed for further development with the request for a full working prototype.
The initial prototype was completed in December of 1937 and first flew in 1938 and fitted with Nakajima Hikari 530kW / 710 horsepower engines. Despite a poor showing, a second improved prototype was made in an attempt to address issues in stability, strength and power. The second prototype was selected for production over the Nakajima model.
Production D3A1 aircraft features included slightly smaller elliptical wings, with narrow dive brakes and carrying spatted landing gears, a 1000-hp / 745kW Mitsubishi Kinsei 43 radial in a redesigned cowling, tandem cockpits under transparent canopies, one movable and two fixed machine-guns, and normal bombload of one 250-kg (551-lb) weapon on swinging arms, plus two 60-kg (132-lb) under the outer wings. A dorsal fin extension considerably improved the aircraft's manoeuvrability. Carrier trials were flown in August 1940, and substantial numbers of D3Als were operational from land bases in China and Indo-China from October 1940.
Standard armament of production models was 3 x 7.7mm machine guns. Two Type 97 Light Machine Guns were fixed to fire forward and controlled by the pilot while a single Type 92 Heavy Machine Gun was fitted in a flexible mount in the rear cockpit.
Early "Vals" were flown in limited land-based operations in the Indo-China theatre though the rest of the war would see them operating in unison with her Imperial Japanese Navy carrier-based counterparts. The D3A series of aircraft (code named "Val" by the Allies) were thought to be all but extinct when the war in the Pacific began. The awakening came in the form of the surprise attack on Pearl Harbour as D3A's made up the principle attack air arm in that assault.
At Pearl Harbor, 126 aircraft dive-bombed targets with great accuracy, and were the only type in the first wave of attackers. Subsequently the D3A1, or Type 99 carrier- based bomber Model 11, was in the forefront of Pacific battles, receiving the Allied code name 'Val'. In April 1942 a very small force sank the cruisers HMS Dorsetshire and Corn-wall and the carrier Hermes, achieving direct hits with more than four bombs out of five. But in the battles of the Coral Sea, off Guadalcanal, Santa Cruz and the Solomons, both the D3A1 and the Japanese aircraft carriers suffered such crippling losses and forced withdrawal by most of the survivors to land bases.
In June 1942 production of the D3A1 ended after 478 were built, replaced by the more powerful and better-streamlined D3A2 with 1300-hp Kin-sei 54, and increased fuel capacity.
Aichi built a total of 816 of this model, the Type 99 Model 22, by June 1944, and Showa also built 201 by the end of the war. Like all Japanese warplanes of the post-1942 period, the D3A2 had no chance. Nearly all operated from land airstrips, suffered severe losses and accom-plished little. By mid-1944 most were in use as trainers (D3A2-K), but large numbers were then reassigned to front-line duty in the Kamikaze role focusing in and around the areas of Leyte and Okinawa during the final year of the war.
Production amounted to 476 D3Als and 1,016 D3A2. The Allied reporting name was 'Val'.
D3As would end up being responsible for the destruction of more Allied shipping vessels than any other Axis aircraft during the war.
Nakajima Hikari 1 Radial, 530kW
Engine: 1 x Mitsubishi Kensei-53, 750kW
Wingspan: 14.36 m / 47 ft 1 in
Length: 10.20 m / 33 ft 6 in
Height: 3.85 m / 12 ft 8 in
Wing area: 34.9 sq.m / 375.66 sq ft
Take-off weight: 3650 kg / 8047 lb
Empty weight: 2408 kg / 5309 lb
Max. speed: 385 km/h / 239 mph
Cruise speed: 295 km/h / 183 mph
Ceiling: 9300 m / 30500 ft
Range: 1500 km / 932 miles
Armament: 3 x 7.7mm machine-guns, 1 x 250-kg bomb, 2 x 60-kg bombs
Engine: 1 x Mitsubishi Kinsei 54 radial, 1,300 horsepower.
Span: 14.365 m / 47 ft 1.5in
Length: 10.195 m / 33 ft 5.5 in
Height: 12.63ft (3.85m)
Gross weight: 3800 kg / 8377 lb
Empty Weight: 5,666lbs (2,570kg)
Maximum speed: 430 km/h (267 mph / 232kt).
Maximum Range: 840miles (1,352km)
Rate-of-Climb: 1,640ft/min (500m/min)
Service Ceiling: 34,449ft (10,500m)
Bombload; 816 lb
Armament: 2 x 7.7mm fixed forward-firing machine guns
1 x 7.7mm trainable machine gun in rear cockpit position.
Bombload: 1 x 551lb bomb under-fuselage OR 2 x 132lb bombs under wings
Engine: 1 x Mitsubishi Kinsei, 1,045 hp
Length: 34.75 ft / 10.57 m
Wing span: 47.7 ft / 14.53 m
Weight empty: 5,770 lb / 2,617 kg
Max speed: 270 mph / 430 kph
Range: 840 miles / 1,350 km
Crew: 1 pilot and 1 gunner
Armament: 2 x mg
Bomb load: 550 lb / 250 kg