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The Keystone B-3A was a bomber aircraft developed for the United States Army Air Corps by Keystone Aircraft in the late 1920s.

Design and development

The B-3 was originally ordered as the LB-10A (a single-tail modification of the Keystone LB-6), but the Army dropped the LB- 'light bomber' designation in 1930.

Although the performance of the B-3A was hardly better than that of the bombers flown at the end of World War I, it had come a long way in terms of flight safety.

Operational history

The B-3A was a member of the last family of biplanes operated by the US Army; it remained in service until 1940. A few years after it was first produced, the introduction of all-metal monoplanes rendered it almost completely obsolete.

Variants

;LB-10

:The last of the 17 LB-6s ordered (S/N 29-27) was converted with a re-designed single fin and rudder and two 525 hp Wright R-1750E engines. Delivered to Wright Field on 7 July 1929, it was wrecked on 12 November 1929.

;LB-10A

:This version used Pratt and Whitney R-1690-3 Hornet engines and was slightly smaller, in both wingspan and length. A total of 63 were ordered (S/N 30-281/343). All were re-designated as the B-3A before any deliveries were made, with the final 27 built as B-5A with Wright engines.

;B-3A

:Ordered as LB-10A, 36 delivered as B-3A (S/N 30-281/316). The first aircraft was delivered in October 1930.

;B-5A

:Ordered as B-3A, re-engined with Wright R-1750-3 Cyclone engines, 27 built (S/N 30-317/343).

Operators

;

  • United States Army Air Corps
  • 2d Bombardment Group, Langley Field, Virginia
  • 20th Bomb Squadron – operated B-3A and B-5A 1931–1932
  • 49th Bomb Squadron – operated B-3A and B-5A 1931–1932
  • 96th Bomb Squadron – operated B-3A and B-5A 1931–1932
  • 4th Composite Group, Nichols Field, Luzon, Philippines
  • 28th Bomb Squadron – operated B-3A 1932–1937
  • 2nd Observation Squadron- operated B-3A 1938–1940
  • 5th Composite Group, Luke Field, Territory of Hawaii
  • 23d Bomb Squadron – operated B-5A 1932–1937
  • 72d Bomb Squadron – operated B-5A 1932–1936
  • 6th Composite Group, France Field, Panama Canal Zone
  • 25th Bomb Squadron – operated B-3A 1932–1936
  • 7th Bombardment Group, March Field, California
  • 9th Bomb Squadron – operated B-3A 1931–1934
  • 11th Bomb Squadron – operated B-3A 1931–1934
  • 31st Bomb Squadron – operated B-3A 1931–1934
  • 19th Bombardment Group, Rockwell Field, California
  • 30th Bomb Squadron – operated B-3A 1932–1936
  • 32d Bomb Squadron – operated B-3A 1932–1935
  • Air Corps Advanced Flying School, Kelly Field, Texas
  • 42d Bomb Squadron – operated B-3A and B-5A 1935–1936

;

  • Philippine Army Air Corps
  • 10th Bombardment Squadron

Specifications (B-3A)

See also

References

;Notes

;Bibliography

  • Andrade, John. U.S. Military Aircraft Designations and Serials since 1909. Leicester, UK: Midland Counties Publications, 1979, pp.&nbsp;43, 135. .
  • The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985). London: Orbis Publishing, 1985, p.&nbsp;2255.
  • Maurer, Maurer. Combat Squadrons of the Air Force, World War II. Maxwell AFB, Alabama: Air Force Historical Studies Office, 1982. .
  • Encyclopedia of American Aircraft
  • Photograph of B-3 on the ground
  • Photograph of B-3 landing
  • USAF Museum article on LB-10
  • USAF Museum article on B-3