A product of John Northrop's influence on Douglas design philosophy, the Dauntless stemmed from the Northrop BT-1 which began to enter service with the US Navy in spring 1938. One of the production BT-1s served as the prototype for a new naval dive-bomber, allocated the designation XBT-2, however, by the time that this entered production in 1940, Northrop had become a division of the Douglas Company, resulting in the SBD designation to identify Douglas as the manufacturer of the new scout/dive-bomber.

There had been structural and engine changes, and while the SBD retained a general family likeness to its progenitor, it was really a very different aeroplane. Of low-wing cantilever configuration, it was of all-metal construction except for fabric-covered control surfaces. Features of the wing design included slots adjacent to the leading edge forward of the ailerons, and hydraulically actuated perforated dive-brakes above and below the trailing edge of the wing outboard to the ailerons, and below the wing centre-section and beneath the fuselage. Fuselage construction included a number of watertight compartments, the tail unit was conventional, and the main units of the tailwheel type landing gear retracted inward to lie flush within wells formed in the wing centre-section. Arrester gear was provided for shipboard operation. Accommodation was provided for a crew of two in tandem cockpits, housed beneath a continuous transparent canopy, and provided with dual controls. The powerplant of the prototype was a 1,000 hp (746 kW) Wright XR-1820-32 Cyclone radial engine.

Testing of the prototype showed not only its superiority over the earlier Northrop BT-1, but performance and flight characteristics that immediately singled it out as an exceptional aircraft. Initial production orders for 57 SBD-1s and 87 SBD-2s were placed on 8 April 1939, the SBD-2s differing by having increased fuel capacity and armament revisions. SBD-1s began to enter service with the US Marine Corps in late 1940, equipping Marine Squadron VMB-2, with deliveries to VMB-1 following in early 1941. The SBD-2s went to the US Navy, and by the end of 1941 were serving aboard the USS Enterprise with Squadron VB-6, and with VB-2 on the USS Lexington.

An improved SBD-3 version began to enter service in March 1941, introducing self-sealing tanks (and with increased fuel capacity), armour protection, bullet-proof windscreen, a 1,000 hp (746 kW) Wright R-1820-52 engine, and armament changes that initiated the standard of two 12.7 mm (0.50 in) and two 7.62 mm (0.30 in) machine guns. The SBD-3 was followed into production by the SBD-4, which differed only by having a 24-volt instead of 12-volt electrical system. Production of these two versions totalled 1,364 units, making possible a wider distribution of these much needed and important aircraft to US Navy squadrons which included VB-3, VB-5, VS-2, VS-3, VS-5 and VS-6, as well as to many US Marine Corps squadrons.

Most extensively built was the SBD-5, produced in a new Douglas factory at Tulsa, Oklahoma. This differed from earlier versions in having a 1,200 hp (895 kW) R-1820-60 engine and increased ammunition capacity as well as introducing illuminated gunsights for both the ; fixed forward-firing and rear cockpit flexibly-mounted machine-guns. A total of 2,409 were built for the US Navy before Douglas turned to the final production variant, the SBD-6, with an even more powerful R-1820-66 engine and increased fuel tankage. Also supplied to the US Navy in small numbers were photo-reconnaissance variants of the earlier production versions, with camera installations and related equipment, under the designations SBD-1P, SBD-2P and SBD-3P. Nine examples of the SBD-5 version were supplied for service with the Royal Navy's Fleet Air Arm in January 1945, these being designated Dauntless DB Mk I, but none of them was used operationally. Another small quantity was supplied to Mexico. Although the US Navy and US Marine Corps use of the Dauntless in a first-line capacity tailed off in late 1944, many late-version aircraft remained in use for some years after the end of World War II.

A Douglas SBD-5 V.C.40 US Navy Air Force - Torokina, Bougainville, New Guinea April 1944

The success of the German Junkers Ju 87 as a dive-bomber, when Hitler's armoured columns raced over much of Europe in 1940, made the US Army conscious of the fact that it possessed no significant aircraft within this category. Accordingly 168 of the US Navy's SBD-3 version were ordered from Douglas as a matter of some urgency, these being delivered in the summer of 1941 under the US Army designation A-24. They were virtually identical to the SBD-3, except for the deletion of the arrester hook, and the provision of an inflated tailwheel tyre instead of the solid rubber favoured by the US Navy. About a third of these aircraft were despatched to the Philippines in November 1941 for service with the USAAF's 27th Bombardment Group, but as they were still at sea when Pearl Harbour was attacked, they were diverted instead to Australia, equipping the 91st Bombardment Squadron in February 1942, and subsequently the 8th Bombardment Squadron. Both of these units found the A-24 lacking in performance and range for operational deployment in this theatre.

Despite these apparent shortcomings, the US Army continued to procure A-24s during 1942, receiving first 170 A-24As (equivalent to the US Navy's SBD-4), and finally 615 A-24Bs (SBD-5). None were deployed with significant success, confirming the experience of Ju 87 usage in Europe and Africa, that their role was strictly confined and within that limited role, of course, they were indeed the 'tool for the job'. Their failure in US Army service was due to the fact that there was no identical job for them to do. Despite this, a number remained in USAAF/USAF service for some years after the end of World War II.

Nicknames:  Barge; Clunk; Speedy-D; Speedy-3; Slow But Deadly; Banshee (A-24).

Specifications (SBD-6):

Engine: One 1,350-hp Wright R-1820-66 Cyclone 9-cylinder radial piston engine
Weight: Empty 6,535 lbs., Max Takeoff 9,519 lbs.
Wing Span: 41ft. 6in.
Length: 33ft. 0in.
Height: 12ft. 11in.

Performance:
Maximum Speed: 255 mph
Cruising Speed: 185 mph
Ceiling: 25,200 ft.
Range: 773 miles

Armament:
Two forward firing 12.7-mm (0.5-inch) machine guns;
Two 7.62-mm (0.3-inch) machine guns on flexible mounts;
Under-fuselage mountings for up to 1,600 pounds of bombs;
Wing hardpoints for up to 650 pounds of bombs.

Number Built:  5,936