The fundamental design of the SBD Dauntless originated at the Northrop El Segundo plant. When the factory was sold to Douglas Aircraft, the XBT-2 project, which was already in development, was renamed XSBD-1. Douglas continued the development, which formed the basis for the SBD Dauntless.
Mass production began in April 1939, with 57 SBD-1s built for the Marine Corps and 87 SBD-2s for the Navy.
Following the fall of France, an order for 174 SBD-3s was placed. Based on lessons learned from the war in Europe, many improvements were implemented. Although the horsepower remained the same, the engine was upgraded to the improved R-1820-52. The aircraft's armor protection was also significantly enhanced, with reinforced armor plating for the crew and the full adoption of self-sealing fuel tanks.
The armament was also upgraded. The twin fixed machine guns in the nose were changed from 7.7mm to 12.7mm, and the rear gunner's single 7.7mm swiveling machine gun was replaced with a twin-barrel setup. Other changes included upgrading the electrical system from 12V to 24V and lowering the engine's air intake to improve forward visibility. These modifications increased the aircraft's weight and slightly reduced its top speed. Despite this, after the start of the war between the U.S. and Japan, an additional 500 SBD-3s were ordered, bringing the total production to 584. These aircraft played a crucial role in the Battle of Midway and the Battle of the Coral Sea.
Deliveries of the SBD-4 began in October 1942. This variant was equipped with a radio navigation aid system and a basic airborne radar, which greatly improved its combat capability compared to the SBD-3. It also featured an additional electric fuel pump and a separate emergency pump. Furthermore, the propeller was changed from a fixed-pitch type to a Hamilton Standard Hydromatic constant-speed propeller, allowing for more efficient use of engine power. A total of 780 SBD-4s were produced, more than the SBD-3.
The Dauntless continued with the SBD-5 and SBD-6 variants and was also adopted by the Army as the A-24. It not only dominated as America's premier dive bomber for an era but its low-wing monoplane layout, retractable landing gear, and tandem crew arrangement also heavily influenced the design of many subsequent propeller-driven dive bombers.
Specifications (SBD-3):
- Crew: 2
- Wingspan: 12.65m
- Length: 9.80m
- Height: 4.14m
- Loaded Weight: 4,717 kg
- Engine: P&W R-1820-52 (1,000 hp takeoff power)
- Maximum Speed: 402 km/h
- Armament: 2 x fixed 12.7mm machine guns, 2 x swiveling 7.7mm machine guns