Aichi D3A

https://en.wikipedia.org/wiki/Aichi_D3A

The Aichi D3A Type 99 Carrier Bomber (Allied reporting name "Val") is a World
War II carrier-borne dive bomber. It was the primary dive bomber of the Imperial
Japanese Navy (IJN) and was involved in almost all IJN actions, including the
attack on Pearl Harbor.

The Aichi D3A was the first Japanese aircraft to bomb American targets in the
war, commencing with Pearl Harbor and U.S. bases in the Philippines, such as
Clark Air Force Base. Vals sank more Allied warships than any other Axis
aircraft.

In mid-1936, the Japanese Navy issued the 11-Shi specification for a monoplane
carrier-based dive bomber to replace the existing D1A biplane then in service.
Aichi, Nakajima, and Mitsubishi all submitted designs, with the former two
subsequently being asked for two prototypes each.

The Aichi design started with low-mounted elliptical wings inspired by the
Heinkel He 70 Blitz. It flew slowly enough that the drag from the landing gear
was not a serious issue, so fixed gear was used for simplicity. The aircraft was
to be powered by the 529 kW (709 hp) Nakajima Hikari 1 nine-cylinder radial
engine.

The first prototype was completed in December 1937, and flight trials began a
month later. Initial tests were disappointing. The aircraft was underpowered and
suffered from directional instability in wide turns, and in tighter turns it
tended to snap roll. The dive brakes vibrated heavily when extended at their
design speed of 200 knots (370 km/h), and the Navy was already asking for a
faster diving speed of 240 knots (440 km/h).

The second aircraft was extensively modified before delivery to try to address
the problems. Power was increased by replacing the Hikari with the 626 kW (839
hp) Mitsubishi Kinsei 3 in a redesigned cowling, and the vertical tail was
enlarged to help with the directional instability. The wings were slightly
larger in span and the outer sections of the leading edges had wash-out to
combat the snap rolls, and strengthened dive brakes were fitted. These changes
cured all of the problems except the directional instability, and it was enough
for the D3A1 to win over the Nakajima D3N1.


Role
Carrier-based dive bomber

Manufacturer
Aichi Kokuki KK

First flight
January 1938

Introduction
1940

Retired
1945

Primary user
Imperial Japanese Navy

Number built
1,495
(479 D3A-1)
(1016 D3A-2)

Developed into
Yokosuka D3Y Myojo

In December 1939, the Navy ordered the aircraft as the Navy Type 99 Carrier
Bomber Model 11 (kanjo bakugekiki, usually abbreviated to ?? kanbaku.). The
production models featured slightly smaller wings and increased power in the
form of the 746 kW (1,000 hp) Kinsei 43 or 798 kW (1,070 hp) Kinsei 44. The
directional instability problem was finally cured with the fitting of a long
dorsal fin-strake which started midway down the rear fuselage, and the aircraft
actually became highly maneuverable.

Armament was two forward-firing 7.7 mm (0.303 in) Type 97 machine guns, and one
flexible 7.7 mm (.303 in) Type 92 machine gun in the rear cockpit for defense.
Normal bombload was a single 250 kg (550 lb) bomb carried under the fuselage,
swung out under the propeller on release by a trapeze. Two additional 60 kg (130
lb) bombs could be carried on wing racks located under each wing outboard of the
dive brakes.

The D3A1 commenced carrier qualification trials aboard the aircraft carriers
Akagi and Kaga during 1940, while a small number of aircraft made their combat
debut from land bases over China. Starting with the attack on Pearl Harbor, the
D3A1 took part in all major Japanese carrier operations in the first 10 months
of the war. They achieved their first major success against the Royal Navy
during their Indian Ocean raid in April 1942. Val dive bombers scored over 80%
hits with their bombs during attacks on two heavy cruisers and an aircraft
carrier during the operation. During the course of the war, Val dive bombers
often combined their attacks upon enemy warships with the IJN Nakajima B5N Kate
torpedo bomber; consequently enemy vessels were often sunk by a combination
strike of bombs and torpedoes. However, there were occasions when just the Vals
would make the attacks, or at least score the sinking hits. Discounting the
Pearl Harbor strike, which also used the B5N for level bombing and torpedo
attacks, Val dive bombers were credited with sinking the following Allied
warships:

USS Peary, American destroyer, 19 February 1942 – Australia (Darwin)
USS Pope, American destroyer, 1 March 1942 – Pacific Ocean
USS Edsall, American destroyer, 1 March 1942- Pacific Ocean
USS Pecos, American oiler, 1 March 1942- Pacific Ocean
HMS Cornwall, British heavy cruiser, 5 April 1942 – Indian Ocean
HMS Dorsetshire, British heavy cruiser, 5 April 1942 – Indian Ocean
HMS Hector, British armed merchant cruiser, 5 April 1942 – Indian Ocean
HMS Tenedos, British destroyer, 5 April 1942 – Indian Ocean
HMS Hermes, British aircraft carrier, 9 April 1942 – Indian Ocean
HMAS Vampire, Australian destroyer, 9 April 1942 – Indian Ocean
USS Sims, American destroyer, 7 May 1942 – Pacific Ocean
USS De Haven, American destroyer, 1 February 1943 – Pacific Ocean
USS Aaron Ward, American destroyer, 7 April 1943 – Pacific Ocean
USS Brownson, American destroyer, 26 December 1943 – Pacific Ocean
USS Abner Read, American destroyer, sunk by kamikaze 1 November 1944 – Pacific
Ocean
USS William D. Porter, American destroyer, sunk by kamikaze 10 June 1945 – Japan
(Okinawa)

As the war progressed, there were instances when the dive bombers were pressed
into duty as fighters in the interceptor role, their maneuverability being
enough to allow them to survive in this role. In June 1942, an improved version
of the D3A powered by a 969 kW (1,299 hp) Kinsei 54 was tested as the Model 12.
The extra power reduced range, so the design was further modified with
additional fuel tanks to bring the total tankage to 900 L (240 US gal), giving
it the range needed to fight effectively over the Solomon Islands. Known to the
Navy as the Model 22, it began to replace the Model 11 in front-line units in
autumn 1942, and most Model 11s were then sent to training units.

When the Yokosuka D4Y Suisei became available, the D3A2s ended up with
land-based units or operating from the smaller carriers, which were too small to
handle the fast-landing Suisei. When American forces recaptured the Philippines
in 1944, land-based D3A2s took part in the fighting, but were hopelessly
outdated and losses were heavy. By then, many D3A1s and D3A2s were operated by
training units in Japan, and several were modified with dual controls as Navy
Type 99 Bomber Trainer Model 12s (D3A2-K). During the last year of the war, the
D3A2s were pressed back into combat for kamikaze missions.

Specifications (D3A2 Model 22)

General characteristics
Crew: 2
Length: 10.195 m (33 ft 5 in)
Wingspan: 14.365 m (47 ft 2 in)
Height: 3.847 m (12 ft 7 in)
Wing area: 34.9 m2 (376 sq ft)
Empty weight: 2,570 kg (5,666 lb)

D3A1: 2,408 kg (5,309 lb)Gross weight: 3,800 kg (8,378 lb)

D3A1: 3,650 kg (8,050 lb)Powerplant: 1 × Mitsubishi Kinsei 54 14-cylinder
air-cooled radial piston engine, 970 kW (1,300 hp) for take-off
1,200 hp (890 kW) at 3,000 m (9,800 ft)1,100 hp (820 kW) at 6,200 m (20,300 ft)
Other engines710 hp (530 kW) Nakajima Hikari I - 1st prototype840 hp (630 kW)
Mitsubishi Kinsei 3 - 2nd prototype1,000 hp (750 kW) Mitsubishi Kinsei 43 - D3A1
Model 11 (early production)1,070 hp (800 kW) Mitsubishi Kinsei 44 - D3A1 Model
11 (late production)Propellers: 3-bladed metal constant-speed propeller

Performance
Maximum speed: 430 km/h (267 mph; 232 kn) at 6,200 m (20,300 ft)

D3A1: 387 km/h (240 mph; 209 kn) at 3,000 m (9,800 ft)Cruise speed: 296 km/h
(184 mph; 160 kn) at 3,000 m (9,800 ft)
Range: 1,352 km (840 mi; 730 nmi)

D3A1: 1,472 km (915 mi)Service ceiling: 10,500 m (34,400 ft)

D3A1: 9,300 m (30,500 ft)Time to altitude: 3,000 m (9,800 ft) in 5 minutes 48
seconds

D3A1: 3,000 m (9,800 ft) in 6 minutes 27 secondsWing loading: 108.9 kg/m2 (22.3
lb/sq ft)

D3A1: 104.6 kg/m2 (21.4 lb/sq ft)Power/mass: 3.9 kg/kW (6.4 lb/hp)

D3A1: 4.9 kg/kW (8 lb/hp)
Armament

Guns: 2x forward-firing 7.7 mm (0.303 in) Type 97 machine guns in the forward
fuselage upper decking + 1x 7.7 mm (0.303 in) Type 92 machine gun on a flexible
mount in the rear cockpit
Bombs: 1x 250 kg (550 lb) under the fuselage and 2x 60 kg (130 lb) bombs under
the wings




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