The excellent flight characteristics of the Douglas O-2 family led to the conversion of 40 O-2Ks in 1930 as basic trainers for the US Army. Dual controls were installed and armament was deleted, the modified aircraft then being designated Douglas BT-1. The only O-32 to be built was given dual controls, also in 1930, and became designated BT-2. Thirty O-32As were modified similarly to the O-2Ks; used by US Army and National Guard units for basic training these were redesignated BT-2A. Some 146 BT-2B aircraft were built as such, the first appearing in 1931. Powered by the 336kW Pratt & Whitney R-1340-11 radial, they survived many years in basic training units.