aircraft. Internal bomb bay and revised equipment. 121 built, including two prototypes refitted to this standard. Note: Breffort and Joiuineau say that 100 RB4 aircraft were built. MB.133 Prototype with redesigned tail, 1 built. MB.134 Prototype with two Hispano-Suiza 14AA engines, 1 built. MB.135 A four engined derivative of the MB.134, powered by four Gnome-Rhône 14M 14 cylinder radial engines. MB.136 Operators French Air Force operated 141 aircraft. Vichy France Vichy aviation operated some aircraft. Luftwaffe operated captured aircraft in restricted roles. Polish Air Forces in exile in France Groupe de Bombardement Marche Polonais Specifications (MB.131RB.4) See also References Bibliography Green, William. War Planes of the Second World War: Volume Seven Bombers and Reconnaissance Aircraft. London: Macdonald, 1967. External links Dassault official home page MB.131 1930s French bomber aircraft 1930s French military reconnaissance aircraft Aircraft first flown in 1934 Twin piston-engined tractor aircraft