The B-3 was originally ordered as theLB-10A (a single-tail modification of theKeystone LB-6), but the Army dropped theLB- 'light bomber' designation in 1930.
Although the performance of the B-3A was hardly better than that of the bombers flown at the end ofWorld War I, it had come a long way in terms of flight safety.
The B-3A was a member of the last family ofbiplanes 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.
The last of the 17LB-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 withWright R-1750-3 Cyclone engines, 27 built (S/N 30-317/343).
Andrade, John.U.S. Military Aircraft Designations and Serials since 1909. Leicester, UK: Midland Counties Publications, 1979, pp. 43, 135.ISBN0-904597-22-9.
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.ISBN0-89201-097-5.
.jpg)
