Model Variants (Including Prototypes)
Model 123 - Base Model Project Designation as pursued by Martin.
XB-907 - US Army Evaluation Designation of Model 123.
XB-907A - Modified US Army Evaluation Designation of Model 123.
XB-10 - USAAC Modified Model based on the XB-907A model.
YB-10 - Modified XB-10 models
B-10 - Base Production Model Designation
YB-10A - based on YB-10 model but fitted instead with Wright R-1820-31 radial piston engines.
B-10B - Initial and Main Production Model Designation.
B-10M - Target Tug Conversion Models of B-10B.
YB-12 - Improved B-10 Model fitted with Pratt & Whitney R-1690-11 Hornet radial piston engines.
B-12A - "Improved B-10" Production Model
YB-13 - Proposed Re-engined Variant Model
A-15 - Proposed Attack Model Variant
YO-45 - Experimental Testing Platform
Model 139 - Export Designation for B-10 Model
Model 139WA - Argentina Export Model Designation for demonstration model.
Model 139WAA - Argentina Export Model Designation; fielded with Argentine Army units.
Model 139WAN - Argentine Export Model Designation; fielded with Argentine Naval units.
Model 139WC - Chinese Export Model Designation.
Model 139WH - Netherlands Export Model Designation.
Model 139WS - Soviet Demonstrator Model
Model 139WSM - Siam Export Model Designation
Model 139WSP - Proposed Spanish Export Model
Model 139WT - Turkish Export Model Designation