Model Variants (Including Prototypes)
V-51 - Prototype
BC-51 - Prototype Designation for USAAC contract competition.
VF-51 - Based on the BC-51 prototype
VF-54 - Refined VF-51 design
VF-54A - Revised VF-54 model
BT-13 USAAC Base Production Model Designation; 300 initially ordered.
BT-13A - Fitted with Pratt & Whitney engines.
BT-13B - Fitted with Pratt & Whitney engines.
SNV-1 - US Navy designation for the BT-13A series.
SNV-2 - US Navy designation for the BT-13B series.
BT-15 - Fitted with Wright-series R-975 radial engine.