Keystone LB-6

The Keystone LB-6 and its sister LB-7 were a 1920s American light bomber built by the Keystone Aircraft company for the United States Army Air Corps. It was called the Panther by the company but adoption of the name was rejected by the U.S. Army.

The aircraft was in competition with the Curtiss XB-2 for production in early 1928. Although the Curtiss aircraft was clearly the better of the two, the conservative Army Air Corps leadership chose the Wright Cyclone-powered LB-6 and the Pratt & Whitney-powered LB-7, ordering 35 aircraft.

The LB-6/LB-7 was the first operational service model of a 13,000 lb (5,897 kg) twin-tail biplane bomber of a series produced by Keystone. 35 served operationally between 1929 and 1934. A number of variants were built for test and evaluation purposes but never placed into production or service. The LB-10 variant became the basis for the B-3 to B-6 series of similar bombers that were the last biplane bombers ordered by the Air Corps.

Read more about Keystone LB-6:  Development, Operational History, Variants, Operators, Specifications (LB-6)