B-18 / Douglas DB-1 (Douglas Bomber 1)
The Douglas B-18 was originally designed and built as the DB-1 (Douglas Bomber #1) for the Army Air Corps 1934 requirement for a long range bomber. The DB-1 was based on the Douglas DC-2 and retained many of the latter aircraft's features, including the wing and aft fuselage. Faced with the tactical-technical requirements of the US Air Corps at the beginning of 1934 for a bomber capable of carrying twice the bomb load twice as far as a Martin B-10, Douglas believed that it could solve this problem based on engineering experience and technology of designing DC-2 - commercial transport aircraft, which at that time was preparing to fulfill its first flight. Experienced aircraft, built on their own initiative by various companies to meet the requirements of the US Army, were evaluated in Wright Field (Ohio) in August 1935.
Among these machines were the Boeing Model 299, the Douglas DB-1 and the Martin 146. The first was built as the B-17 Flying Fortress, the latter was produced as an export version of the B-10 / B-12 series of the Martin aircraft. Although the Boeing entry was clearly superior, the DB-1 was initially favored by the Army General Staff for two reasons. First, the Boeing Model 299 crashed during testing. The crash was the result of pilot error but was technically disqualified from the competition. Second, the DB-1 could be built for about half the cost of the Model 299 (B-17). The General Staff considered the B-17 too expensive and opted for an order for 99 B-18s and only 13 Y1B-17s in 1936. Douglas DB-1 (Douglas Bomber 1) was ordered in January 1936 for immediate serial production under the designation B-18.
The prototype DB-1 retained almost the same tail and power plant as the DC-2. In the design of the wing were made two differences: its range was increased by 1.37 m, and the wing was moved upward in height. The fuselage was taller. This made it possible to accommodate six crew members in it and include a nasal and super-turret turret, a bombing officer's cabin and an internal bomb compartment. In addition to this, a third fire point was provided with a machine gun firing through the tunnel at the bottom of the fuselage. The power plant included two Wright R-1820-45 Cyclone 9 engines with a capacity of 930 hp. Under the first contract, 133 B-18 aircraft (including the experimental DB-1) were produced.
Serial version, which was named Bolo, had a number of changes in equipment and more powerful star-shaped reciprocating engines Wright R-1820-45. The last B-18 was distinguished by the electric drive of the nasal turret and was designated DB-2. The second version, designated B-18A, appeared in 1937 with a revised nose with extensive glazing in which the bomb-aimer/navigator sat above and ahead of the nose gun, which was housed in a ball-type turret. 255 of this version were ordered. Only 217 were delivered as B-18A. The contracts for B-18A were placed in June 1937 (177 aircraft) and in the middle of 1938 (another 40). This model was distinguished by the presence of the position of the bombing operator and even more powerful Wright R-1820-53 engines.
Most of the bomber squadrons of the US Air Corps were in 1940 were equipped with airplanes B-18 or B-18A. In December 1941, B-18 and B-18A were kept at military bases in the Philippines, Hawaii, Alaska and the Panama Canal Zone. A large number of aircraft were destroyed at the first raids by the Japanese. Only in the Philippines B-18 was not used for long in combat operations, mainly as transport aircraft. In 1942-1943 years. B-18A were used for patrolling the US coast, some of the vehicles were converted into special anti-submarine B-18Bs (they were equipped with search radars and magnetic-anomalous anti-submarine patrol detectors). Brazilian "Digby" was also used as a marine patrol in 1939 - 1944. The Royal Canadian Air Force also received 20 B-18A aircraft, which, under the designation Digby Mk1 were involved in maritime patrolling. The designation B-18C was received by the two aircraft modified for antisubmarine operations.
Douglas produced 370 of the production model B-18 Bolos, and their availability during the late 1930s allowed the Air Corps to train bomber crews. The B-18 Bolos made up most of the bombers deployed outside the country as the United States entered World War II. The aircraft production was discontinued in 1938. It was disarmed in the USA in August 1943, in Canada - in November 1946.
C-58
B-18 Bolos were used for antisubmarine operations in American and Caribbean waters and as trainers and transports. Two aircraft were converted into transport under the designation C-58.
XB-22
The XB-22 was proposed by Douglas as an improved version of the B-18A with more powerful Wright R-2600 radial engines of 1,600 hp each. No aircraft were ordered because better twin-engine bombers were already being designed including the Douglas B-23 Dragon.
B-23 Dragon
In November 1938, Douglas used the stronger wings of the DC-3, a new and better streamlined fuselage, and large fin and rudder for the Bolo's successor — the B-23 Dragon - an almost total redesign. The first of 38 B-23 Dragons built flew July 27, 1939. The 26,500-pound (12,000-kilogram) B-23 bomber incorporated the first tail turret installed in an Air Corps bomber and was powered by two 1,600-horsepower Wright R-2600-3 engines. Following the war, many Dragons were adapted as corporate aircraft.
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