| D3A | |
|---|---|
 Aichi D3A1 from carrierAkagi. | |
| General information | |
| Type | Carrier-baseddive bomber |
| Manufacturer | Aichi Kokuki KK |
| Primary user | Imperial Japanese Navy Air Service |
| Number built | 1,495 (479 D3A1) (1016 D3A2) |
| History | |
| Introduction date | 1940[1] |
| First flight | January1938 |
| Retired | 1945 |
| Developed into | Yokosuka D3YMyōjo |
TheAichi D3A (Navy full designation "Type 99 Carrier Bomber";Allied reporting name "Val"[a]) is aWorld War IIcarrier-bornedive bomber. It was the primary dive bomber of theImperial Japanese Navy (IJN) and was involved in almost all IJN actions, including theattack on Pearl Harbor.
The Aichi D3A was the first Japanese aircraft to bomb American targets in the war, commencing withPearl Harbor and U.S. bases in thePhilippines, such asClark Air Force Base. They sank moreAllied warships than any otherAxis aircraft.[2][3][4]
In mid-1936, the Japanese Navy issued the 11-Shi specification for amonoplane carrier-based dive bomber to replace the existingD1Abiplane then in service.[1]Aichi,Nakajima, andMitsubishi 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 theHeinkel He 70Blitz. It flew slowly enough that the drag from thelanding gear was not a serious issue, so the fixed gear was used for simplicity.[5] The aircraft was to be powered by the 529 kW (709 hp)Nakajima Hikari 1 nine-cylinderradial engine.
The firstprototype was completed in December 1937, and flight trials began a month later, after which it was designated as D3A1. Initial tests were disappointing. The aircraft was underpowered and suffered from directional instability in wide turns, and in tighter turns it tended tosnap roll. Thedive brakes vibrated heavily when extended at their design speed of 200knots (370 km/h), and the Navy was already asking for a faster diving speed of 240 knots (440 km/h)[6][7]
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 redesignedcowling, and thevertical tail was enlarged to help with the directional instability. The wings were slightly larger in span and the outer sections of theleading edges hadwash-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 theNakajima D3N1.[8][7]
In December 1939, the Navy ordered the aircraft as theNavy Type 99 Carrier Bomber Model 11 (kanjō bakugekiki, usually abbreviated to 艦爆kanbaku.[9]). 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 dorsalfin-strake which started midway down the rear fuselage, and the aircraft actually became highly maneuverable.[10][7]
In June 1942, an improved version of D3A1, powered by a 969 kW (1,299 hp) Kinsei 54, was tested and designated as D3A2 or theModel 12. The extra power reduced range, so the design was further modified with additionalfuel tanks to bring the total tankage to 900 L (240 US gal), giving it the range needed to fight effectively over theSolomon Islands. Known to the Navy as theModel 22, it began to replace the Model 11 in front-line units in the autumn of 1942, and most Model 11s were then sent to training units. While some late production models of D3A1 were fitted with apropeller spinner, it became a standard with D3A2.[7]
Thepilot position was equipped with a Type 95telescopic gunsight in the earlier models and a Type 99 in the later models, which were used for aiming the bomb during the dive. Theobserver/navigator position was equipped with a Type 97 Mk1drift sight, which was a long vertical tube located in the front-left of the observer's seat. In addition, the observer position was equipped with adrift meter that was mounted on the floor in the front-right of the observer's seat. The observer also operated a Type 96 Mk2radio set that was mounted in front of the observer's seat and behind the pilot's seat. On top of the radio set was a Type 3reflectorcompass for precise navigation.[11]
Armament was two fixed forward-firing 7.7 mm (0.303 in)Type 97 machine guns, and one flexible 7.7 mm (.303 in)Type 92 machine gun at the rear end ofcockpit, which was operated by the observer. Normal bomb load was a single 250 kg bomb (e.g.,Type 99 No 25semi-AP or Type 98 No 25 land bomb) carried under the fuselage, swung out under the propeller on release by a trapeze. Two additional 60 kg bombs (e.g., Type 99 No 6 semi-AP or Type 2 No 6 land bomb) could be carried on wing racks located under each wing outboard of the dive brakes.[7][12]
Initially, D3A dive bombers were painted in silver. During the summer of 1941, the paint finish changed to light olive grey. The color changed again in early 1942 to dark green.[7]
An individual D3A dive bomber was commanded by the senior ranking crew member aboard, which could be the observer rather than the pilot.[7] This was in contrast to theUnited States Navy, where the pilot was almost always the commander of a dive bomber. For example,Petty Officer First ClassKiyoto Furuta was serving as a pilot toLieutenant Takehiko Chihaya during theattack on Pearl Harbor,[7] and later on to LieutenantKeiichi Arima during the two carrier battles of theSolomon Islands campaign,[13] both of whom were observers.
The D3A1 first saw combat operation in November 1939, one month prior to its official acceptance as the Navy Type 99 dive bomber. Nakajima sent several examples to the 14th Air group operating atHaikou onHainan island inSouth China. These D3A1s were commanded byLieutenantSadamu Takahashi and supported theImperial Japanese Army in thecapture of Nanning, which was intended to cut the supplies coming fromFrench Indochina. After the capture ofNanning, they continued to be operated in the area in 1940. In May 1940,12th Air Group became the second front-line unit to be equipped with the new D3A1 dive bombers. They first participated in thecapture of Yichang and conducted anti-shipping operations on theYangtze River, west ofYichang, in order to cut the Chinese supplies coming fromChongqing. In September, D3A1s from the 12th Air Group started to flymissions against Chongqing, which was the Chinese capital at the time. After theinvasion of Indochina in autumn 1940, 14th Air Group operated atHanoi and flew missions againstKunming and theBurma Road.[7]
The D3A1 commenced carrier qualification trials aboard theaircraft carriersAkagi andKaga during 1940, while a small number of aircraft made their combat debut from land bases overChina.[10] 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 theRoyal Navy during theirIndian Ocean raid in April 1942. D3A1 dive bombers scored over 80% hits[14] with their bombs during attacks on twoheavy cruisers and an aircraft carrier during the operation.
Before the Indian Ocean raid, the established doctrine regarding attacks against ships was to arm all D3A1 dive bombers with semi-AP bombs. On 5 April 1942, an IJN carrier force attackedColombo onCeylon with half of its complement, while the other half was kept in reserve for strikes against ships. Since a second strike against Colombo was deemed necessary, the dive bombers of the reserve force were rearmed from semi-AP bombs to land bombs. When British heavy cruisers were spotted soon afterwards, the reserve force was sent with a portion of D3A1 dive bombers armed with land bombs. In the subsequent attack, land bombs unintentionally proved very effective in suppressing theanti-aircraft fire from the ships. As a result, the doctrine was modified in order to intentionally equip the first few D3A1 dive bombers with land bombs. This new method was already implemented for the attack that sankHMS Hermes just four days later, and continued to be used from then on.[7]
During 1942, dive bombing attacks by carrier-based D3A1 and D3A2 bombers significantly contributed to sinking of three US fleet carriers:Lexington at theBattle of the Coral Sea,Yorktown at theBattle of Midway andHornet at theBattle of the Santa Cruz Islands. In addition, they damaged the carrierEnterprise both at theBattle of the Eastern Solomons and at theBattle of the Santa Cruz Islands.[15][13] Besides carrier-based units, D3A dive bombers also operated from land bases during the Solomon Islands campaign, where they participated in theGuadalcanal campaign,Operation I-Go,Operation SE and Operation RO, and during theNew Guinea campaign, where they participated in theBattle of Milne Bay andBattle of Buna–Gona. The main land-based unit to operate D3A dive bombers during these campaigns and battles was the2nd/582nd Air Group.[13][16][17]
During the course of the war, D3A dive bombers often combined their attacks upon enemy warships with the IJNNakajima 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 D3As made the attacks, or at least scored the sinking hits. Discounting the Pearl Harbor strike, which also used the B5N for level bombing and torpedo attacks, D3A dive bombers were credited with sinking the following Allied warships (partial list):[18][19]
As the war progressed, there were instances when the dive bombers were pressed into duty asfighters in theinterceptor role, their maneuverability being enough to allow them to survive in this role.[23] When theYokosuka D4YSuisei became available, the D3A2s ended up with land-based units or operating from the smaller carriers, which were too small to handle the fast-landingSuisei. When American forces invaded thePhilippines 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 forkamikaze missions.[24]
A D3A2 is currently under restoration at thePlanes of Fame Museum inChino, California.[25][26]There are two unrestored D3As on display at theNational Museum of the Pacific War in Fredericksburg, Texas.[27][28] In 2022, thePearl Harbor Aviation Museum began acquiring the remains of a D3A from Papua New Guinea for eventual exhibit.
Data fromJapanese Aircraft of the Pacific War[29]
General characteristics
Performance
Armament
Aircraft of comparable role, configuration, and era
Related lists
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