The Soviet Tupolev SB twin-engined, high speed bomber was one of the most outstanding designs of the interwar years. It saw service in Spain and China, and was the backbone of the Soviet bomber force when the Nazi's invaded the Soviet Union in 1941. Includes the ANT-40-1, SB-2-M-100, SB-2-M-100-A, Avia B-71, Avia B-71A, Avia B-71B, SB-2-M-100, SB-2-M-100-A (Modified), SB-2-M-103, SB-bis-3, PS-40, PS-41, PS-41 bis, SB-MMN, and USB variants. Also covers operations in Poland, Finland, and the Russo-German War, as well as aircraft in foreign service.