SBD-1 VMSB-132 1941
In the summer of 1941, the Douglas SBD “Dauntless” became a critical part of the American naval forces, serving as the first purpose-built dive-bomber. This aircraft played a key role in the US Navy’s bombing squadrons, taking on missions with tactics that had evolved significantly since the Marine Corps pioneered dive-bombing in the 1920s.
US Naval Bombing Tactics:
By 1941, the tactics used in naval bombing were well defined, and attacks were categorized into two primary types: glide-bombing and dive-bombing. The difference between these two tactics lay in the altitude of the attack and the angle at which bombs were released:
- Glide-bombing: Attacks were made from an altitude of less than 8,000 feet and at an angle of less than 70°.
- Dive-bombing: Considered more accurate and destructive, dive-bombing attacks were carried out from high altitudes, typically around 15,000 to 17,000 feet, with a steep dive angle of 70°. This steep angle maximized the accuracy of the bombs, though it posed greater risks to the aircraft from enemy fire.
The Navy emphasized that steeper dive angles led to higher hit percentages and reduced the risk of damage to the attacking aircraft. Glide-bombing was less effective, especially against well-defended ships.
Phases of a Dive-Bombing Attack:
Dive-bombing attacks followed a structured sequence:
- Approach: Aircraft would approach the target from a high altitude, around 15,000 feet or more. The doctrine assumed that the extra visibility afforded by this altitude outweighed the potential risk of early detection by enemy radar.
- Delivery: When the aircraft reached the initial point (IP), typically about 10 miles from the target, they would split up and attack from multiple angles. The dive-bombing run began from altitudes between 15,000 and 17,000 feet. At the “push-over” point, pilots would initiate their steep dive, deploying special dive brakes to control the dive and prevent air compression from destabilizing the aircraft.
- Bomb Release: The bombs were released when the aircraft descended to about 2,500 feet. This precise bombing technique was supported by the dive-bomber’s sights and extensive pilot training. According to Lt. Cdr. William O. Burch of VS-5 from the USS Yorktown, pilots would aim by setting their sight so that, at a 70° dive angle, the aim point would fall directly on the target. With practice, pilots became adept at estimating their dive angles accurately.
- Withdrawal: After releasing the bombs, pilots would pull out of their dive at mast-level altitude, engaging in evasive maneuvers, or “jinking,” to avoid enemy anti-aircraft fire as they exited the target area.
Challenges with Early SBD Models:
Early versions of the SBD Dauntless used a telescopic sight for aiming, but this system had a major flaw: the sight would fog up during dive-bombing runs. This issue occurred when the aircraft descended from the cold high-altitude air into the warmer air at lower altitudes, causing visibility problems for the pilots. This defect significantly hampered the SBD’s performance in early battles, such as those in 1942 during the Pacific campaign, leading to disappointing results.
Improvements with New Models:
The sighting problem was addressed with the introduction of newer aircraft models. The SBD-5 Dauntless and the Curtiss SB2C “Helldiver”, which entered service in 1943–44, were equipped with reflector-type sights. These were more reliable and solved the fogging issue that plagued the earlier telescopic sights, allowing for more effective bombing accuracy and contributing to the success of dive-bombing operations in the latter stages of the war.
The development and use of the Dauntless dive-bomber showcased the importance of precision bombing in naval warfare, especially against well-defended targets, and laid the foundation for the advancements seen in later dive-bombing aircraft.