631s. The 633 was however offered for export and attracted orders from Romania, China and Greece. Potez 632 Bp.2One example of the dive bomber prototype was started, but completed as a 633 however with Hispano-Suiza engines. It was sold to Switzerland for evaluation. Potez 639 AB2The single two-seat attack bomber prototype was converted as a standard 633. Reconnaissance variants Dissatisfied with its strategic reconnaissance aircraft such as the troublesome Bloch MB.131, the Armée de l'air required the development of a derivative of the Potez 631 for this role. Potez 637Strategic reconnaissance aircraft. The observer was housed in a gondola under the fuselage; this arrangement resulted in an aircraft that retained most of the qualities of the 631. 60 examples were ordered in August 1938 and delivered. At the same time, the Armée de l'Air was desperate to re-equip its army cooperation units which had particularly antiquated equipment, but since the development of the 637, had completely changed its mind about how the observer position should be arranged. Potez was therefore required to develop a variant that, while retaining the wings, engines and tail surfaces of the 631, hosted the observer in a more conventional nose glasshouse. Potez 63.11Because the pilot needed to be seated above the observer, the fuselage was taller, which resulted in reduced top speed and manoeuvrability. As a result, the 63.11 proved very vulnerable, despite being protected with some armour and basic self-sealing coating over the fuel tanks. As a secondary light bomber capability was part of the requirements (though it was rarely if ever used), the fuselage accommodated a tiny bomb bay, carrying up to eight 10 kg-class bombs. This bomb bay was replaced by an additional fuel tank on late examples. Additionally, two 50 kg-class bombs could be carried on hardpoints under the inner wings. Frontal armament was originally one, then three MAC 1934s under the nose, and many 63.11s were equipped with the same additional guns in wing gondolas as the 631s. The first Potez 63.11 No.1 and second No.2 prototypes first flew in December 1938, and no less than 1,365 examples were on order in September 1939, of which 730 were delivered, making the 63.11 the most numerous variant of the family by far. Operators French Air Force (Armée de l'air) French Naval Aviation (Aviation Navale/Aéronautique navale) Vichy France Vichy French Air Force (Armée de l'air de l'Armistice) Free French Air Forces (Forces