The Douglas B-18 Bolo is an American medium bomber which served with the United States Army Air Corps and the Royal Canadian Air Force (as the Digby) during the late 1930s and early 1940s. The Bolo was built by the Douglas Aircraft Company, based on its DC-2, and was developed to replace the Martin B-10.
By 1940, it was considered to be underpowered, to have inadequate defensive armament, and to carry too small a bomb load. Many were destroyed during the attacks on Pearl Harbor and the Philippines in December 1941.
In 1942, the surviving B-18s were relegated to antisubmarine, transport duty, and training. A B-18 was one of the first American aircraft to sink a German U-boat, U-654 on 22 August 1942 in the Caribbean.
|Manufacturer||Douglas Aircraft Company|
|First flight||April 1935|
|Retired||1946 Brazilian Air Force|
|Primary users||United States Army Air Corps|
United States Army Air Forces
Royal Canadian Air Force
Brazilian Air Force
US$58,500 in 1935 (equivalent to $1.1 million today)
|Developed from||Douglas DC-2|
|Developed into||Douglas B-23 Dragon|
In 1934, the United States Army Air Corps put out a request for a bomber with double the bomb load and range of the Martin B-10, which was just entering service as the Army's standard bomber. In the evaluation at Wright Field the following year, Douglas showed its DB-1. It competed with the Boeing Model 299 (later developed into the Boeing B-17 Flying Fortress) and Martin Model 146.
While the Boeing design was clearly superior, the crash of the B-17 prototype (caused by taking off with the controls still locked) removed it from consideration. During the depths of the Great Depression, the lower price of the DB-1 ($58,500 vs. $99,620 for the Model 299) also counted in its favor. The Douglas design was ordered into immediate production in January 1936 as the B-18.
The DB-1 design was essentially that of the DC-2, with several modifications. The wingspan was 4.5 ft (1.4 m) greater. The fuselage was deeper, to better accommodate bombs and the six-member crew; the wings were fixed in the middle of the cross-section rather than to the bottom due to the deeper fuselage. Added armament included nose, dorsal, and ventral gun turrets.
The initial contract called for 133 B-18s (including DB-1), using Wright R-1820 radial engines. The last B-18 of the run, designated DB-2 by the company, had a power-operated nose turret. This design did not become standard. Additional contracts in 1937 (177 aircraft) and 1938 (40 aircraft) were for the B-18A, which had the bombardier's position further forward over the nose-gunner's station. The B-18A also used more powerful engines.
Deliveries of B-18s to Army units began in the first half of 1937, with the first examples being test and evaluation aircraft being turned over to the Materiel Division at Wright Field, Ohio, the Technical Training Command at Chanute Field, Illinois, the Aberdeen Proving Ground, Maryland, and Lowry Field, Colorado. Deliveries to operational groups began in late 1937, the first being the 7th Bombardment Group at Hamilton Field, California.
Production B-18s, with full military equipment fitted, had a maximum speed of 217 mph, cruising speed of 167 mph, and combat range of 850 miles. By 1940, most USAAC bomber squadrons were equipped with B-18s or B-18As.
However, the deficiencies in the B-18/B-18A bomber were becoming readily apparent to almost everyone. In range, in speed, in bomb load, and particularly in defensive armor and armament, the design came up short, and the Air Corps conceded that the aircraft was obsolete and totally unsuited in the long-range bombing role for which it had originally been acquired. To send crews out in such a plane against a well-armed, determined foe would have been nothing short of suicidal.
However, in spite of the known shortcomings of the B-18/B-18A, the Douglas aircraft was the most numerous American bomber type deployed outside the continental United States at the time of the attack on Pearl Harbor. It was hoped that the B-18 could play a stopgap role until more suitable aircraft such as the Boeing B-17 Flying Fortress and Consolidated B-24 Liberator became available in quantity.
When war came to the Pacific, most of the B-18/B-18A aircraft based overseas in the Philippines and in Hawaii were destroyed on the ground in the initial Japanese onslaught. The few Bolos that remained played no significant role in subsequent operations.
The B-18s remaining in the continental US and in the Caribbean were then deployed in a defensive role in anticipation of attacks on the US mainland. These attacks never materialized. B-17s supplanted B-18s in first-line service in 1942. Following this, 122 B-18As were modified for anti-submarine warfare. The bombardier was replaced by a search radar with a large radome. Magnetic anomaly detection (MAD) equipment was sometimes housed in a tail boom. These aircraft, designated B-18B, were used in the Caribbean on anti-submarine patrol. On 2 October 1942, a B-18A, piloted by Captain Howard Burhanna Jr. of the 99th Bomb Squadron, depth charged and sank the German submarine U-512 north of Cayenne, French Guiana.
Two aircraft were transferred to Força Aérea Brasileira in 1942 and used with a provisional conversion training unit set up under the provisions of Lend-Lease. They were later used for anti-submarine patrols. They were struck off charge at the end of the war. In 1940 the Royal Canadian Air Force acquired 20 B-18As (as the Douglas Digby Mark I), and also used them for patrol duties, being immediately issued to 10 Squadron to replace the squadron's Westland Wapitis.
Bolos and Digbys sank an additional two submarines during the course of the war. RCAF Eastern Air Command (EAC) Digbys carried out 11 attacks on U-boats. U-520 was confirmed sunk by Flying Officer F. Raymes' crew of No. 10 (BR) Squadron, on 30 October 1942. east of Newfoundland. However, the antisubmarine role was relatively short-lived, and the Bolos were superseded in this role in 1943 by Consolidated B-24 Liberators which had a much heavier payload and a substantially longer range which finally closed the mid-Atlantic gap.
Surviving USAAF B-18s ended their useful lives in training and transport roles within the continental United States, and saw no further combat action. Two B-18As were modified as unarmed cargo transports under the designation C-58. At the end of the war, those bombers that were left were sold as surplus on the commercial market. Some postwar B-18s of various models were operated as cargo or crop-spraying aircraft by commercial operators.
Some of the Douglas Digbys in Canadian service were converted to either C-58s or used for training.
**Note: Most aircraft destroyed 7–8 December 1941 at outbreak of World War II
Only six B-18s still exist, five of them preserved or under restoration in museums in the United States:
Data from McDonnell Douglas aircraft since 1920 : Volume I
The chief of the air corps called the turret “ingenious” and invited Tucker to a conference at Wright Field to discuss the needs of gun turrets with the military.
The 10th Missile Squadron is a United States Air Force unit. It is assigned to the 341st Operations Group, stationed at Malmstrom Air Force Base, Montana. The squadron is equipped with the LGM-30G Minuteman III Intercontinental ballistic missile, with a mission of nuclear deterrence.13th Strategic Missile Division
The 13th Strategic Missile Division is an inactive United States Air Force unit. Its last assignment was with Fifteenth Air Force, based at Francis E. Warren Air Force Base, Wyoming. It was inactivated on 2 July 1966.
Initially formed as an air defense organization in the Caribbean, the unit later commanded Boeing B-17 Flying Fortress groups of Eighth Air Force in England. Its units carried out strategic bombardment missions over Occupied Europe and Nazi Germany during World War II. During the Cold War, the unit was a command and control organization of Strategic Air Command, controlling early ICBM wings in the Midwest.21st Airlift Squadron
The 21st Airlift Squadron is part of the 60th Air Mobility Wing at Travis Air Force Base, California. It operates C-17 Globemaster III aircraft carrying out United States Air Force global transport missions, duties which involve airlift and airdrop missions as well as provision of services and support in order to promote quality of life for both soldiers and civilians in situations requiring humanitarian aid. First formed as the 21st Transport Squadron at Archerfield Airport, Australia on 3 April 1942. Activated in the wake of the United States withdrawal from the Philippines, the squadron was formed with a mixture of personnel withdrawn from Clark Field and some reinforcements which had arrived in Australia but did not see combat in the Philippines. The squadron was hastily put together with some impressed civilian Douglas DC-2s and DC-3s.
With the end of the Second World War, the 21st remained in the Pacific and assigned to the 374th. Curtiss C-46 Commandos were assigned to the squadron along with the C-47s that it had used during wartime. The squadron was first moved to Occupied Japan, where it conducted airlift missions in support of Fifth Air Force and MacArthur's headquarters from Atsugi Airfield, near Tokyo.
When the Korean War began in 1950, the 21st was again called into action. The squadron moved to Tachikawa Air Base, Japan, where it exchanged its long-range C-54s for twin-engined C-46 and C-47 aircraft. The squadron carried much needed equipment and supplies, along with personnel across the Sea of Japan to marginal dirt airstrips in South Korea on an almost continuous basis. The squadron participated in all major engagements in Korea, including the massive airdrops at Sunchon in which 290.8 tons of supplies and 1,093 paratroopers were dropped in three days. The squadron operated from various airfields in Japan, flying combat resupply and evacuation missions back to Japan until December 1952 when the 21st was relieved of combat duty, and re-equipped with C-54 Skymasters. In 1967, the squadron was redesignated the 21st Tactical Airlift Squadron. In 1968, during the siege of Khe Sanh, crews from the 21st performed massive combat airdrops and assault landing supporting the besieged outpost.22nd Airlift Squadron
The 22nd Airlift Squadron, sometimes written as 22d Airlift Squadron, is part of the 60th Air Mobility Wing at Travis Air Force Base, California. It operates Lockheed C-5 Galaxy aircraft supporting the United States Air Force global reach mission worldwide. The mission is to provide services and support which promote quality of life and project global power through combat-proven airlift and airdrop.365th Intelligence, Surveillance and Reconnaissance Group
The 1st Search Attack Group was a United States Army Air Forces unit that served during World War II. Its last assignment was with First Air Force. It was based at Langley Field, Virginia throughout its existence, and equipped with Boeing B-17 Flying Fortress, Douglas B-18 Bolo, and Consolidated B-24 Liberator aircraft. It was disbanded on 20 April 1944.
The original mission of the group was the development of equipment and tactics best suited for aerial anti-submarine warfare. Among the devices that the group helped develop or test were the radar altimeter, the magnetic anomaly detector, the sonobuoy, improved airborne depth charges, long-range navigation systems, and airborne microwave radar.The group also conducted training on equipment and antisubmarine tactics for Army Air Forces units and personnel. During the summer and fall of 1942, most of the unit's aircrews deployed to the Caribbean, where they conducted missions against German U-boats. After the Navy assumed responsibility for land based aerial antisubmarine operations in 1943, the unit continued to conduct radar training for bomber crews until it was disbanded.
The group was reconstituted in 1985 as the 365th Electronic Warfare Group, but was not active under that designation. It was redesignated the 365th Intelligence, Surveillance and Reconnaissance Group and activated at Nellis Air Force Base, Nevada, where it provides intelligence support for the Adversary Tactics Group and the United States Air Force Weapons School.835th Bombardment Squadron
The 835th Bombardment Squadron is an inactive United States Army Air Forces unit. It was activated in January 1941 as the 80th Bombardment Squadron and equipped with Douglas A-20 Havoc light bombers. Following the attack on Pearl Harbor the squadron began to fly antisubmarine patrols off the Atlantic coast and over the Caribbean Sea, becoming the 9th Antisubmarine Squadron. After the Navy assumed the unit's mission, it moved to Arizona, where it trained as a Consolidated B-24 Liberator unit, and deployed with its planes to the European Theater of Operations, entering combat on 7 May 1944. In July 1944, the squadron converted to Boeing B-17 Flying Fortresses, continuing combat with the 486th Bombardment Group until April 1945. Following V-E Day it returned to Drew Field, Florida, where it was inactivated on 7 November 1945.89th Tactical Missile Squadron
The 89th Tactical Missile Squadron is an inactive United States Air Force unit. Its last assignment was with the 38th Tactical Missile Wing, based at Pydna Missile Base at Wüschheim Air Station, West Germany. It was inactivated on 22 August 1990.92nd Air Refueling Squadron
The 92nd Air Refueling Squadron, sometimes written as 92d Air Refueling Squadron, is a squadron of the 92nd Air Refueling Wing's 92nd Operations Group, stationed at Fairchild Air Force Base, Washington. It was first activated shortly before the entry of the United States into World War II as the 2nd Reconnaissance Squadron. After training in the Douglas B-18 Bolo in the southeastern United States, the squadron moved to the Pacific Coast after the Japanese attack on Pearl Harbor and participated in antisubmarine patrols with the Consolidated B-24 Liberator. In April 1942, it was redesignated the 392nd Bombardment Squadron. Starting in mid-1942, it also began training crews on the Liberator. It ended these operations in July 1943 and began to prepare for overseas movement. After three months of training, the squadron moved to the Central Pacific, where it flew its first combat mission in November. The 392nd continued combat operations until March 1945, when it was withdrawn and moved to Hawaii, where it conducted routine training and patrol operations until it was inactivated in November 1945.
In July 1957, the 92nd Air Refueling Squadron was established at Bergstrom Air Force Base, Texas by assuming the resources of the inactivating 506th Air Refueling Squadron when Strategic Air Command transferred its fighter units to Tactical Air Command. Three months later, the squadron moved to Fairchild Air Force Base, Washington, where it equipped with Boeing KC-135 Stratotankers, which it has flown for over fifty years. During the Cold War, the squadron maintained half its aircraft on alert. During the Cuban Missile Crisis, all the squadron's tankers were either on alert, deployed, or supporting Boeing B-52 Stratofortresses on airborne alert. The squadron also deployed aircraft to the Pacific to refuel strike aircraft during the Vietnam War.
In 1985, the 392nd Bombardment Squadron was consolidated with the 92nd Air Refueling Squadron. In 1992, the squadron ended its long association with Strategic Air Command and became part of Air Mobility Command. Since consolidation, the squadron has deployed personnel and aircraft to support most major United States operations, including combat and humanitarian support operations. Although it has not participated as a unit, squadron personnel and aircraft have deployed worldwide to support these operations. The squadron operates the Boeing KC-135 Stratotanker aircraft conducting worldwide air refueling missions.Douglas B-23 Dragon
The Douglas B-23 Dragon is an American twin-engined bomber developed by the Douglas Aircraft Company as a successor to (and a refinement of) the B-18 Bolo.List of maritime patrol aircraft
The following is a list of maritime patrol aircraft, which are sometimes referred to as Maritime reconnaissance, coastal reconnaissance or patrol bombers depending on the service and the time period, and are characterized by their use in controlling sea lanes.Líneas Aéreas La Urraca
Líneas Aéreas La Urraca was a Colombian airline.Martin 146
The Martin Model 146 was an unsuccessful American bomber design that lost a 1934–1935 bomber design competition to the prototype for the Douglas B-18 Bolo (itself soon supplanted by the B-17 Flying Fortress).Medium bomber
A medium bomber is a military bomber aircraft designed to operate with medium-sized bombloads over medium range distances; the name serves to distinguish this type from larger heavy bombers and smaller light bombers. Mediums generally carried about two tons of bombs, compared to light bombers that carried one ton, and heavies that carried four or more.
The term was used prior to and during World War II, based on available parameters of engine and aeronautical technology for bomber aircraft designs at that time. After the war, medium bombers were replaced in world air forces by more advanced and capable aircraft.Naval Auxiliary Air Facility Hyannis
Naval Auxiliary Air Facility Hyannis was a United States Navy facility located in Hyannis, Massachusetts operational from 1942 to 1945. It existed as an auxiliary air facility of Naval Air Station Quonset Point.North American XB-21
The North American XB-21, also known by the manufacturer's model designation NA-21, and sometimes referred to by the name "Dragon", was a prototype bomber aircraft developed by North American Aviation in the late 1930s, for evaluation by the United States Army Air Corps. Evaluated against the Douglas B-18 Bolo, it was found to be considerably more expensive than the rival aircraft, and despite the ordering of a small number of evaluation aircraft, only the prototype was ever built.Transportes Aéreos Sul-Americanos
TASA – Transportes Aéreos Sul-Americanos was a Brazilian airline founded in 1948. It ceased operations in 1949.Tucker gun turret
The Tucker gun turret was a fast-traversing electrically powered gun turret widely described as having been mounted on World War II bombers and on some ground vehicles and small naval vessels like US Navy PT boats. American industrialist Preston Tucker first developed the turret for the experimental Tucker armored car in 1938.
Steve Lehto and Jay Leno, in their biography of Tucker, assert that it is a misconception that Tucker's turret was widely used on US bombers during the war. They assert that different manufacturers were each assigned contracts to develop different turrets for different planes, and that Tucker's firm was to build turrets for the Douglas B-18 Bolo. In the end no Tucker turrets equipped any bombers.
When Tucker was under investigation by the Security and Exchange Commission, a half-hour film entitled Tucker: The Man and his Car was prepared and shown to the Commission members. Lehto and Leno described the film's narrator "gushing" over Tucker and noted: "A short section on his wartime efforts to create the Tucker Combat Car introduced the Tucker Turret and may have been the source of the myth that his turrets were widely used during the war."
A Hollywood biopic of Tucker covered Tucker's production of the turret, prompting reviewers to characterize the turret design as "incredibly ergonomic, effective and convenient".
Douglas military aircraft
|Army/Air Force sequence|
|Revived original sequence|