Keystone B-3

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

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• 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<ref name="B-3A fact">"Fact Sheet – Keystone B-3A." National Museum of the United States Air Force. Retrieved: 14 July 2017.</ref>
  • 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

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• Philippine Army Air Corps
  • 10th Bombardment Squadron

References

Notes

Bibliography

• Andrade, John. U.S. Military Aircraft Designations and Serials since 1909. Leicester, UK: Midland Counties Publications, 1979, pp. 43, 135. Template:ISBN.
• The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985). London: Orbis Publishing, 1985, p. 2255.
• Maurer, Maurer. Combat Squadrons of the Air Force, World War II. Maxwell AFB, Alabama: Air Force Historical Studies Office, 1982. Template:ISBN.

External links

• 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