Douglas B-18 Bolo | History, Specs, and Service

The Douglas B-18 Bolo – a twin-engine heavy bomber – was designed by the Douglas Aircraft Company to serve the United States Army Air Corps. This aircraft was developed to replace the Martin B-10 which was the U.S. Army Air Corps’ first metal, low-wing monoplane. The B-18, despite its early promise, was quickly overshadowed in the early 1940s by other, more capable aircraft, like the Boeing B-17 Flying Fortress. Although it was not a primary role, the B-18 did play a key part in World War II. This included the Pacific and Atlantic Theaters.

This article takes a look at all aspects of the Douglas B-18, including the evolution, operation history, obsolescence as well as the various variants as they relate to World War II.

Design and Development

Douglas B-18 began its life in 1934. The United States Army Air Corps (USAAC) issued a requirement for a heavy bomber with twin engines. Specifications called for an airplane that had twice the bomb load of the Martin B-10 which entered service in 1934, as well as a much greater range. Competition was intense to satisfy this requirement. Boeing and Martin all had designs in contention.

Douglas Aircraft was to enter the competition using the DB-1. It was derived by the Douglas DC-2 a civilian airliner. The DB-1 featured a mid-wing positioning for an enclosed bay and Wright R-1820 radial aircraft. The aircraft featured manual-operated gun turrets on the nose, ventral, and dorsal positions. Despite its innovative design, the DB-1 had to compete with Boeing’s B-17 Flying Fortress (which later evolved into the Model 399 ) and Martin 146.

Model Model Model Model Model 299 had a four-engined design that disqualified it due to the cost. Also, the crash Model prototype 299 further delayed selection. Despite being less expensive, the Douglas DB-1 ($58,500) was ultimately chosen. The U.S. Army Air Corps first ordered the B-18 in January 1935, which began the B-18’s long service.

Design features

The B-18’s main purpose was to offer a cost-effective alternative to the B-17 and other competitors. The Twin-Engine Configuration allowed the B-18 to be more economically maintained and operated. But it was also slower, had fewer weapons, and carried a lighter bomb load when compared with its modern contemporaries, like the B-17. This design had a narrower and deeper fuselage with a wing mid-section in order to accommodate an enclosed bomb bay. Its six-person crew included the pilot, the copilot, the bombardier, as well the gunners of the nose, ventral and doA Wright R-1820-5 Cyclone radial engine powers the B-18rsal guns.

A Wright R-1820-5 Cyclone radial engine powers the B-18. They each produce 1,000 horsepower. This gives the aircraft a speed of 216 mph (348) km/h. Its flight range was about 900–1,400 miles (1,448–2,253 km), and it holds up to 2000 lbs (907kg) bombs. In comparison to the newer, faster bombers of the 1940s and 1930s, its relatively low speed and limited load were major drawbacks.

Operational Background

Early Service

The B-18’s service life commenced in 1937. This was when the 7th Bombardment Group acquired the aircraft. B-18s were stationed at bases around the United States as well as abroad. These included Hawaii, the Philippines, and Panama. In 1940, the B-18 began to reveal its flaws. Newer aircraft were superior to the B-18, including the Boeing B-17 Flying Fortress. The B-17 had much higher payload capacities, greater speeds, and more robust defensive weaponry.

Defence armament on the B-18, in addition to its limited speed and bomb load, was unsuitable by World War II’s standards. Gun turrets operated manually were not effective against the aircraft of enemy, especially as technology in aviation had rapidly improved in the years before the war.

World War II, Early Losses and the Anti-Submarine Warfare Role

B-18s were considered out-of-date when the United States entered World War II on December 7th, 1941. During the Japanese attacks on Pearl Harbor in December 1941, the majority of B-18s located in Hawaii were destroyed during the initial assault. Few B-18s survived in Hawaii or in the Philippines. They were mostly ineffective for the Pacific campaigns that followed.

(anti-submarine warfare) was repurposed from B-18s located in the Caribbean or along the U.S. East Coast. In order to combat the German U-boats, B-18s with Search Radar or Magnet anomaly Detection were fitted. This conversion was known as B-18B and allowed the aircraft to attack German subs located in the Atlantic.

A notable B-18 achievement in this role is the destruction of the German U-boat U512 on 2 October 1942. B-18A was piloted off the coasts of South American Coast by Captain Howard Burhanna Jr. A U.S. aircraft successfully sank the German submarine.

Declination and Replacement

Despite the B-18’s success as an anti-submarine aircraft, its limitations were evident. In 1943, newer aircraft with greater capabilities, such as the B-24 Liberato,r were assigned the task of combating submarines. B-18s were increasingly used for train and cargo missions, as their obsolete technology was no longer a concern. In the United States a few B-18s underwent conversion to Cargo Transports and were given the name C58. Post-war, commercial operators also employed them to spray crops.

Royal Canadian Air Force

In 1940, the Royal Canadian Air Force bought a batch of B-18s that were renamed Douglas Digby Mk I. These aircraft were mostly used to perform patrol duty over the North Atlantic or the waters of Canada’s East Coast. The 10 squadron, RCAF, played a crucial role in employing B-18s to conduct anti-submarine warfare. Digbys is credited with sinking German U-boats at least twice during WWII, but the most notable was U 520.

B-18

Over the years, B-18s have undergone a series of changes, leading to a wide range of variations.

Legacy

After World War II ended, the B-18 aircraft was not in service as a combat aircraft with the U.S. Army Air Forces. The remainder of the aircraft was relegated to secondary roles. These included teaching and transport. Agriculture also became a possibility. B-18s are used in the civilian sector, for example, as flamethrowers or crop-dusters.

Despite having a relatively brief combat record and despite being relatively uninteresting in terms of its actual performance on the battlefield, it remains an integral part of aviation’s history. In the years leading up to World War II it served as an interim bomber in the U.S. Army Air Corps, helping bridge the gap between less advanced bombers from the 1930s to more sophisticated aircraft of World War II.

Today, many B-18s remain in museums throughout the United States. While some are still undergoing renovation, others have already been restored. This is to better showcase the aircraft’s historic significance in the early years of American Air Power.

B-18A Specifications

The Douglas B-18 Bolo represented an early chapter in the U.S. development of military bombers. Faster designs overtook the pre-WWI era. However, the Anti-Submarine Warfare that it contributed to during World War II should not have been underestimated. Newer bombers superseded b-18s in time as technology improved. Their place in history, however, remains solid, having played a major role in the evolution of military aviation.