01/15/2019. Remarks by Johan Visschedijk: "The combat inadequacies of the S.VII led to substantial revision of the basic design to accept the 200 hp Hispano-Suiza 8B engine and paired synchronized 0.303 in (7.7 mm) Vickers machine guns. Designated S.XIII C1, the new fighter embodied many features of the S.VII, notably the single-bay interplane bracing with intermediate struts, rod-and-crank aileron actuation and circular radiator cowling. It bore a close family resemblance to the S.XII, but was, in fact, a completely separate and structurally different aircraft. All major dimensions were larger than those of the S.VII, and an initial batch of 20 S.XIIIs was under construction in February 1917.

The Aviation Militaire had 372 S.XIIIs on strength by April 1, 1918. Orders placed with the parent company and eight other contractors (ACM de Colombes, Bernard, Bleriot, Borel, Kellner, Levasseur, Nieuport and S.C.A.) were eventually to exceed 8,470 aircraft, but it seems unlikely that more than 7,300 were completed. In service, the S.XIII was handicapped by the several shortcomings of the geared engine, but saw widespread service. As at October 1, 1918, 764 S.XIIIs were with operational units of the Aviation Militaire, and the RFC received 61 Kellner-built examples between November 1917 and April 1918. Others went to Italian, Belgian and US fighter units, and later production aircraft had modified wings with blunt tips and the 220 hp Hispano-Suiza 8Bc, 8Bd or 8Be. The S.XIII remained in French service until 1923."