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Designed as light bomber and reconnaissance aircraft, Dauntless SBD (Scout Bomber Douglas) monoplanes served during WWII with US Marine Corps, Army and Navy air squadrons. The Dauntless originated with the design of the Northrop BT-1 of which the Northrop Corporation was a subsidiary of The Douglas Aircraft Corporation. Northrop was dissolved on September 8, 1937 and Northrop designs continued production under Douglas. The aircraft was a low-wing cantilever configuration of all-metal construction, except for fabric covered flight controls. It had a two-man tandem cockpit with dual flight controls and hydraulically actuated perforated split dive-brakes. On November 28, 1937 numerous major modifications were ordered of the BT-1, one of which was the landing gear being changed from retracting backwards into large fairing trousers beneath the wings, to folding laterally into recessed wheel wells. The new model, the XBT-2, became the forerunner of the now well known Dauntless.

When the aircraft was delivered to Anacosta for flight testing with a larger 1,000 hp Wright R-1920-G133 engine, the performance was greater than expected with a top speed of 265 mph (429 km/h). The aircraft was then delivered to Langley Memorial Aeronautical Institute for wind tunnel tests and numerous design changes were made. Modifications were made to the flight controls, leading edge slots and a dorsal fin were added. The perforated flaps developed on the BT-1 were retained to eliminate tail buffeting during diving maneuvers.

The initial order was for 36 aircraft, but was increased to 144 which included both SBD-1s and SBD-2s. Modifications included a center auxiliary fuel tank for a total capacity of 210 gallons. The production engine was a 1,000 hp Wright R-1820-32. Armament consisted of two forward firing 0.50 in machine guns (mg) in the engine nose cowling and one flexible rearward firing, drum-fed 0.30 mg. A swinging bomb cradle carried a 1,000 lb bomb below the fuselage and a 100 lb bomb was mounted under each wing. The bomb cradle was designed so that the bomb would swing clear of the prop during dive-bombing maneuvers.

The SBD-2 fuel capacity was increased to 310 gallons with the elimination of the center auxiliary tank and replaced with 65 gallon tanks in the outer wing panels. SDB-2s were later retrofitted with self sealing tanks, which reduced total fuel capacity to 260 gallons. Armament was reduced by the removal of one forward firing 0.50 mg in the engine nose cowling.

The SBD-3 (A-24-DE) was the first fully combat ready version with a total production of 585 airplanes.3 Flotation gear was removed, alclad replaced dural for construction, armor protection and bullet-proof windscreen were installed and the engine was changed to a 1,000 hp Wright R-1820-52. Forward firing armament was changed to two 0.50 mg, (same as the SBD-1) and rear armament was increased with a twin, belt-fed 0.30 mg. The SBD-4 retained the same engine as the -3, but a new hydromatic constant-speed propeller was installed. The electrical system was upgraded to 24 volts and an electric fuel pump replaced a hand-operated fuel boost pump. The USAAF A-24-DE Dauntless was basically the same airplane as the SBD-3 except for Army instrumentation and a pneumatic tail wheel tire installed instead of the Navy solid rubber tire. The arrestor gear was eliminated on the A-24.

The SBD-5 (A-24B-DT) was the main production model built with a larger 1,200 hp Wright R-1820-60 engine. The engine air intake was removed from the upper cowling which was the main distinguishing mark of all earlier models. The bomb load was increased to 2,250 lb with a 1,600 lb bomb under the fuselage and a 325 lb bomb under each wing. The twin rearward-firing guns were no longer add-ons and were factory installed. The SBD-6 was fitted with a 1,350 hp Wright R-1820-66 engine and was equipped with ASV (Air to Surface Vessel) radar. The all-metal fuel tanks were replaced by self-sealing bladder fuel tanks with a total capacity of 284 gallons.

The first squadrons to receive the Dauntless were USMC VMB-2 in late 1940 and VMB-1 in early 1941. The first Navy squadrons were equipped with SBD-2s and at the end of 1941 were assigned to VB-6 on the USS Enterprise squadron and VB-2 on the USS Lexington. Other Navy squadrons equipped with the SBD Dauntless were VB-3, VB-5, VS-2, VS-3, VS-5 and VS-6. Other USMC squadrons were equipped with the plane as well. Nine examples were sent to the Royal Navy Fleet Air Arm and were designated the Mk.I but were not used operationally. A small quantity were supplied to Mexico.

At the time of the attack of Pearl Harbor, the Dauntless was the standard dive bomber and was the first US Navy plane to sink an enemy ship (Japanese sub I-70) in WWII, just three days after Pearl Harbor. The first real test came on May 7,1942, when US aircraft carriers, USS Lexington and USS Yorktown, faced three Japanese carriers in the Battle of the Coral Sea. The two-day battle was the first naval battle in which victory was decided by aircraft alone. Dauntless dive-bombers fought well alongside other US aircraft and were credited with forty of the ninety-one enemy aircraft downed. During the battle, the US lost the carrier USS Lexington and the Japanese lost the light carrier Shoho, which was sunk by Dauntless and Devastator bombers. The Shokaku received serious bomb damage and Zuikaku's air group was badly depleted, eliminating these carriers from the upcoming Midway operation. While the battle was a technical victory for Japan, the US had prevented Japanese ships from supporting an invasion of Port Moresby, New Guinea, and a proposed air assault on Australia.

In the great Battle of Midway in June US naval aircraft, spearheaded by Dauntless dive-bombers, sank the Japanese carriers, Akagi, Kaga, and Soryu. Only the Hiryu remained operational which would launch a retaliatory strike against the USS Yorktown later in the day. However, before the day ended, US carrier planes found and bombed Hiryu, putting her out of action. A Japanese cruiser and 250 aircraft were also destroyed, for the loss of only one US carrier, a destroyer and 150 aircraft. The Battle of Midway turned the tide of war against the Japanese in the Pacific.

As the war went on, the Dauntless equipped no less than twenty Marine squadrons and were retained until late 1944. It was the main type US navy dive-bomber and was not only used in the Pacific, but during the Allied landing in North Africa and in the Battle of the Atlantic. The Dauntless had the lowest attrition rate of any US carrier aircraft, because of its ability to absorb battle damage. Dauntless aircraft accounted for many Japanese aircraft shot down in air-to-air combat, and finished their wartime career as antisubmarine bombers and as attack aircraft, carrying depth charges and rocket projectiles respectively. The total production of the Dauntless was 5,938 aircraft built. The first SBD-1 was completed in April 1940 and flown on May 1, 1940 with production continuing until to the end of 1944.

In the summer of 1941, 168 SBD-3s were delivered to the USAAF and were designated as the A-24. The Army had been looking for an airplane to compete with the Junkers Ju-87 dive bomber, but operated no similar aircraft of this type. The A-24 faired rather badly in combat and the USAAF was not as successful with the Dauntless as was the Navy. On 29 Jul 1942, seven A-24s were sent on a bombing mission to Buna, without top cover, and were intercepted by A6M Zeros—only one survived. The A-24 was subsequently withdrawn from first-line service. In spite of the apparent lack of success with the A-24, the USAAF continued procurement with 170, A-24As (SBD-4) and 615, A-24Bs (SBD-5). First-line capacity also tailed off for the US Navy and USMC by late 1944, and the Douglas Dauntless was superseded by the Curtis SBC2 Helldiver.


General characteristics

* Crew: Two
* Length: 33 ft 1 in (10.08 m)
* Wingspan: 41 ft 6 in (12.65 m)
* Height: 13 ft 7 in (4.14 m)
* Wing area: 325 ft² (30.19 m²)
* Empty weight: 6,404 lb (2,905 kg)
* Loaded weight: 10,676 lb (4,843 kg)
* Max takeoff weight: 10,700 lb (4,853 kg)
* Powerplant: 1× Wright R-1820-60 radial engine, 1,200 hp (895 kW)

Performance

* Maximum speed: 255 mph (410 km/h)
* Range: 773 mi (1,240 km)
* Service ceiling: 25,530 ft (7,780 m)
* Rate of climb: 1,700 ft/min (8.6 m/s)
* Wing loading: 32.8 lb/ft² (160.4 kg/m²)
* Power/mass: 0.11 hp/lb (0.18 kW/kg)

Armament

* Guns:
o 2 × 0.50 in (12.7 mm) forward-firing Browning M2 machine guns in engine cowling
o 1 × 0.30 in (7.62 mm) flexible-mounted Browning machine gun in rear (later versions fitted with 2 × machine guns of the same caliber)
* Bombs: 2,250 lb (1,020 kg) of bombs