Keystone B-5

The Keystone B-5 was a light bomber made for the United States Army Air Corps in the early 1930s. The B-5A was a Keystone B-3A with Wright Cyclone rather than Pratt & Whitney engines.

Design and development
Three B-3A (LB-10A) were reengined with Wright R-1750-3 radial engines and were redesignated Y1B-5. The Army Air Corps changed the design of the last 27 LB-10As on order, replacing the Pratt & Whitney R-1690 radial engines with the Wright R-1750-3. The Pratt & Whitney-powered aircraft were designated B-3A, and the Wright-powered aircraft became B-5A. They provided the backbone of the U.S. bomber force from then to 1934.

Operational history
B-5A were first line bombers of the United States for the period between 1930 and 1934. Afterwards, they remained in service primarily as observation aircraft until the early 1940s.

Variants

 * LB-14
 * As LB-10 with 575 hp (429 kW) Pratt & Whitney GR-1860 engines but delivered as the Y1B-5.


 * Y1B-5
 * Three pre-production aircraft redesignated from LB-14 before delivery.


 * B-5A
 * Wright R-1750-3 version originally ordered as B-3A, 27 built

Operators

 * 🇺🇸 United States
 * United States Army Air Corps