Douglas Y1B-7

The Douglas Y1B-7 was a 1930s United States bomber aircraft. It was the first US monoplane given the B- 'bomber' designation. The monoplane was more practical and less expensive than the biplane, and the United States Army Air Corps chose to experiment with monoplanes for this reason. At the time the XB-7 was ordered, it was being tested by Douglas Aircraft as an observational plane.

Douglas Y1B-7 on the ground
Y1B-7 of the 31st Bombardment Squadron
Role Bomber/Observation aircraft
Manufacturer Douglas Aircraft Company
First flight 1931
Retired January 1939
Primary user United States Army Air Corps
Produced 1932
Number built 14
Developed from Douglas O-35

Design and development

In 1929–1930, the Douglas Aircraft Company designed a new twin-engined monoplane observation aircraft to compete with the Fokker XO-27, two prototypes of which had been ordered by the United States Army Air Corps in July 1929, as Douglas feared that the advanced Fokker would challenge Douglas's role as the major supplier of observation aircraft to the Air Corps. The Douglas proposals resulted in the Air Corps placing an order for two prototypes, the XO-35 and XO-36, on 26 March 1930. The two aircraft were to differ only in the engines fitted, with the XO-35 having geared Curtiss V-1570-29 Conqueror engines, while the XO-36 used direct-drive V-1570-23, which both produced 600 hp (450 kW) each.[1][2]

The Douglas design had gull wings mounted high on the aircraft's fuselage, the engines being suspended in streamlined nacelles under the wings by bracing struts. A retractable tailwheel undercarriage was fitted, the mainwheels retracting into the engine nacelles. The fuselage was a semi-monocoque structure with corrugated duralumin covering, which housed the aircraft's crew of four: a nose gunner/observer, a pilot whose cockpit was situated ahead of the leading edge of the wing, an upper gunner who sat in a cockpit aft of the wing, and a radio operator housed within the fuselage. Armament was two .30 in machine guns.[1][2]

The projected performance of the new twin-engined Douglas and Fokker observation aircraft was much greater than the Keystone biplanes (the Keystone B-3, B-4, B-5 and B-6) that equipped the Air Corps light bomber squadrons, and both Fokker and Douglas were instructed to complete one of their prototypes as a bomber, with the XO-36 being redesignated the XB-7, with provision to carry up to 1,200 lb (540 kg) of bombs on racks under the fuselage added.[3]

The XO-36 made its first flight at the Santa Monica, California factory of Douglas in spring 1931.[4] On 22 August 1931, the Air Corps placed an order for a small batch of service test aircraft, consisting of seven Y1B-7 bombers and five Y1O-35 observation aircraft. These differed from the prototypes by having smooth fuselage skins rather than the corrugated skins used on the prototype, while the fuselage was 11 in (280 mm) longer to adjust the aircraft's center of gravity. A revised fuel system was fitted, with more fuel carried in order to give the two-hour endurance specified by the Air Corps. More powerful Conqueror engines were fitted, with all aircraft using geared engines as used on the XO-35.[3]

Operational history

The XO-35 was delivered to the Air Corps at its test center at Wright Field, Ohio on 24 October 1931, with the XB-7 following in July 1932.[4] The twelve service test aircraft were completed between November 1932 and March 1933.[5] The Y1B-7s equipped the 11th and 31st Bombardment Squadrons at March Field, California,[3] while the Y1O-35s were issued to a number of Squadrons, including the 88th Observation Squadron at Brooks Field, Texas.[6] One notable early use of the Y1B-7 was during a May 1933 exercise at Fort Knox, where it was able to outrun biplane fighters like the Boeing P-12, showing that the Air Corps needed more modern fighters.[7]

Despite the aircraft's superior performance to the elderly Keystone biplanes, the Douglas monoplane never entered mass production either in the observation or bomber roles because newer, more capable aircraft, such as the Martin B-10, were under development while a change in Air Corps policy meant that it was no longer interested in buying more twin-engined observation aircraft.[8]

In February 1934, US President Franklin D. Roosevelt cancelled all air mail contracts owing to a scandal relating to the award of contracts, thus initiating the Airmail Emergency, where the Air Corps was tasked with carrying the mail until new contracts could be awarded. The O-35s and B-7s were considered some of the least unsuitable aircraft in the Air Corps inventory for the air mail role, so the six remaining Y1B-7s and the five Y1O-35s, together with the XO-35, were assigned to air mail routes in the western United States, which included hazardous operations over the Rocky Mountains, the Cascade Range and the Sierra Nevada.[9] By the time the Air Corps involvement in air mail flights ended in June 1934, the twelve O-35s and B-7s had flown 1,412 hours on mail flights, while four of the B-7s had been lost as a result of accidents.[10] The last O-35s and B-7s were withdrawn from use in December 1938.[11]


Prototype twin-engined observation aircraft. Two 600 hp (450 kW) geared Curtiss V-1570-29 engines driving three-bladed propellers. One built.[3]
Prototype twin-engined observation aircraft. Two 600 hp (450 kW) direct-drive Curtiss V-1570-23 engines driving two-bladed propellers. Redesignated XB-7. One built.
Prototype light bomber, with two direct-drive 600 hp V-1570-23 engines driving two bladed propellers. One built.[3]
Service test batch of observation aircraft, powered by 650 hp (480 kW) V-1570-39 or 675 hp (503 kW) V-1570-53 engines. Five built.[3]
Service test batch of bombers, powered by 640 hp (480 kW) V-1570-33 or 675 hp V-1570-53 engines. Seven built.[3]


 United States

Specifications (Y1B-7)

Data from McDonnell Douglas aircraft since 1920 : Volume I[12]

General characteristics

  • Length: 45 ft 11 in (14.00 m)
  • Wingspan: 65 ft (20 m)
  • Height: 11 ft 7 in (3.53 m)
  • Wing area: 621.2 sq ft (57.71 m2)
  • Empty weight: 5,519 lb (2,503 kg)
  • Gross weight: 9,953 lb (4,515 kg)
  • Max takeoff weight: 11,177 lb (5,070 kg)
  • Powerplant: 2 × Curtiss V-1570-53 Conqueror V-12 liquid-cooled piston engines, 675 hp (503 kW) each
  • Propellers: 3-bladed metal propellers


  • Maximum speed: 182 mph (293 km/h, 158 kn)
  • Cruise speed: 158 mph (254 km/h, 137 kn)
  • Range: 411 mi (661 km, 357 nmi)
  • Ferry range: 632 mi (1,017 km, 549 nmi)
  • Service ceiling: 20,400 ft (6,200 m)
  • Time to altitude: 10,000 ft (3,000 m) in 8 minutes 42 seconds
  • Wing loading: 16 lb/sq ft (78 kg/m2)
  • Power/mass: 0.135 hp/lb (0.222 kW/kg)


  • Guns: 2 × 0.30 in (7.6 mm) machine guns
  • Bombs: 1,200 lb (540 kg) of bombs carried beneath the fuselage

See also

Aircraft of comparable role, configuration and era

Related lists


  1. ^ a b Pelletier Air Enthusiast March/April 2002, pp. 30, 32.
  2. ^ a b Francillon 1979, pp. 135–136.
  3. ^ a b c d e f g Pelletier Air Enthusiast March/April 2002, p. 32.
  4. ^ a b Francillon 1979, p. 137.
  5. ^ Pelletier Air Enthusiast March/April 2006, pp. 33–34.
  6. ^ Pelletier Air Enthusiast March/April 2006, p. 34.
  7. ^ Pelletier Air Enthusiast March/April 2006, pp. 32–33.
  8. ^ Francillon 1979, p. 138.
  9. ^ Pelletier Air Enthusiast March/April 2006, p. 35.
  10. ^ Francillon 1979, p. 139.
  11. ^ Pelletier Air Enthusiast March/April 2006, p.40.
  12. ^ Francillon, René J. (1988). McDonnell Douglas aircraft since 1920 : Volume I. London: Naval Institute Press. pp. 119–124. ISBN 0870214284.
  • Francillon, René J. McDonnell Douglas Aircraft since 1920. London: Putnam, 1979. ISBN 0-370-00050-1.
  • Pelletier, Alain J. "Bombers as Postmen: Boeing Y1O-35 and Y1B-7". Air Enthusiast, No. 122, March / April 2006, pp. 30–40. ISSN 0143-5450.
  • Wagner, Ray. American Combat Planes. New York: Doubleday, 1982. ISBN 0-930083-17-2.

External links

12th Reconnaissance Squadron

The 12th Reconnaissance Squadron is a United States Air Force squadron, assigned to the 69th Reconnaissance Group at Grand Forks Air Force Base, North Dakota, and operates from Beale Air Force Base, California.

The squadron traces its lineage to the Air Service, United States Army 12th Aero Squadron, activated on 2 June 1917 at Kelly Field, Texas. It earned seven Campaign Streamers in World War I flying the French Salmson 2A2 aircraft as a Corps Observation squadron. The squadron again flew tactical reconnaissance missions in France and Northern Europe during World War II as part of Ninth Air Force. As a United States Air Force squadron, it flew reconnaissance missions in the Korean War, Vietnam War, Operation Desert Storm and the Global War on Terrorism.

Aircrews of the 12th have flown over 40 different aircraft since its beginnings in 1917, fought in more than 25 major campaigns, operated from over 60 stations, and received more than 20 unit citations. Today, it continues its history of reconnaissance, now equipped with the RQ-4 Global Hawk Unmanned Reconnaissance Vehicle (UAV).

31st Test and Evaluation Squadron

The 31st Test and Evaluation Squadron (31 TES) is a United States Air Force unit, assigned to the 53d Test and Evaluation Group, stationed at Edwards Air Force Base, California. The 31 TES is an Air Combat Command (ACC) tenant unit at Edwards, providing personnel to support combined test and evaluation on Air Force weapons systems.

The squadron is one of the oldest in the United States Air Force, its origins dating to 26 June 1917, being organized at Kelly Field, Texas. The squadron deployed to England as part of the American Expeditionary Force during World War I. The squadron saw combat during World War II, and later became part of the Strategic Air Command (SAC) during the Cold War.

Air Mail scandal

The Air Mail scandal, also known as the Air Mail fiasco, is the name that the American press gave to the political scandal resulting from a 1934 congressional investigation of the awarding of contracts to certain airlines to carry airmail and to the use of the U.S. Army Air Corps to fly the mail.

In 1930, during the administration of President Herbert Hoover, Congress passed the Air Mail Act of 1930. Using its provisions, Postmaster General Walter Folger Brown held a meeting with the executives of the top airlines, later dubbed the "Spoils Conference", in which the airlines effectively divided among themselves the air mail routes. Acting on those agreements, Brown awarded contracts to the participants through a process that effectively prevented smaller carriers from bidding, resulting in a Senate investigation.

The Senate investigation resulted in a citation of Contempt of Congress against William P. MacCracken, Jr., on February 5, 1934, the only action taken against any former Hoover administration official for the scandal. Two days later Roosevelt cancelled all existing air mail contracts with the airlines and ordered the Air Corps to deliver the mail until new contracts could be let. The Air Corps was ill-prepared to conduct a mail operation, particularly at night, and from its outset on February 19 encountered severe winter weather. The Army Air Corps Mail Operation suffered numerous crashes and the deaths of 13 airmen, causing severe public criticism of the Roosevelt Administration.

Temporary contracts were put into effect on May 8 by the new postmaster general, James A. Farley, in a manner nearly identical to that of the "Spoils Conference" that started the scandal. Service was completely restored to the airlines by June 1, 1934. On June 12 Congress passed a new Air Mail Act cancelling the provisions of the 1930 law and enacting punitive measures against executives who were a part of the Spoils Conferences. Although a public relations nightmare for the administrations of both presidents, the scandal resulted in the restructuring of the airline industry, leading to technological improvements and a new emphasis on passenger operations, and the modernization of the Air Corps.

Air Mail scandal accidents and incidents

In 1934, all United States commercial air mail carrying contracts were cancelled due to controversy over how the contracts had been awarded. The United States Army Air Corps was charged with carrying air mail service, beginning 19 February 1934. Due in part to extremely bad weather, inadequate preparation of the mail pilots, and the inadequacies of pressing military aircraft into duties for which they were not designed, there ensued a series of accidents over the following three months, ending when commercial services were restored. In all, 66 major accidents, ten of them with fatalities, resulted in 13 crew deaths, creating an intense public furor. Only five of the 13 deaths actually occurred on flights carrying mail, but directly and indirectly the air mail operation caused accidental crash deaths in the Air Corps to rise by 15 percent to 54 in 1934, compared to 46 in 1933 and 47 in 1935.The press dubbed this the Air Mail scandal, or the Air Mail fiasco.

This is a list of documented accidents and incidents involving Army Air Corps aircraft during that three month period of 1934.

Curtiss V-1570

The Curtiss V-1570 Conqueror was a 12-cylinder vee liquid-cooled aircraft engine. Representing a more powerful version of the Curtiss D-12, the engine entered production in 1926 and flew in numerous aircraft.

Douglas Aircraft Company

The Douglas Aircraft Company was an American aerospace manufacturer based in Southern California. It was founded in 1921 by Donald Wills Douglas Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas, when it then operated as a division of McDonnell Douglas. McDonnell Douglas later merged with Boeing in 1997.

Fokker XB-8

The Fokker XB-8 was a bomber built for the United States Army Air Corps in the 1920s, derived from the high-speed Fokker O-27 observation aircraft.

Keystone B-6

The Keystone B-6 was a biplane bomber developed by the Keystone Aircraft company for the United States Army Air Corps.

List of United States bomber aircraft

This is a list of United States bomber aircraft

List of accidents and incidents involving military aircraft (1925–1934)

This is a list of notable accidents and incidents involving military aircraft grouped by the year in which the accident or incident occurred. Not all of the aircraft were in operation at the time. For more exhaustive lists, see the Aircraft Crash Record Office or the Air Safety Network or the Dutch Scramble Website Brush and Dustpan Database. Combat losses are not included except for a very few cases denoted by singular circumstances.

See: List of accidents and incidents involving military aircraft before 1925

See: List of accidents and incidents involving military aircraft (1925–1934)

See: List of accidents and incidents involving military aircraft (1935–1939)

See: List of accidents and incidents involving military aircraft (1940–1944)

See: List of accidents and incidents involving military aircraft (1945–1949)

See: List of accidents and incidents involving military aircraft (1950–1954)

See: List of accidents and incidents involving military aircraft (1955–1959)

See: List of accidents and incidents involving military aircraft (1960–1974)

See: List of accidents and incidents involving military aircraft (1975–1979)

See: List of accidents and incidents involving military aircraft (1980–1989)

See: List of accidents and incidents involving military aircraft (1990–1999)

See: List of accidents and incidents involving military aircraft (2000–2009)

See: List of accidents and incidents involving military aircraft (2010–present)

List of bomber aircraft

The following is a list of bomber airplanes and does not include bomber airships, organized by era and manufacturer. A bomber is a military aircraft designed to attack ground or sea targets.

List of cancelled military projects

This is a list of cancelled military projects.

Douglas military aircraft
Ground attack
Training aircraft
USAAS/USAAC/USAAF/USAF bomber designations, Army/Air Force and Tri-Service systems
Original sequences
Main sequence
Long-range Bomber
Tri-Service sequence
USAAC/USAAF observation aircraft
Observation Amphibian


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