During the latter half of World War I, Ing Manlio Stiavelli and Guido Luzzatti of the firm of Vittoria Ducrot at Palermo designed a high-performance fighter in an attempt to allow the company to progress from license production of flying boats designed elsewhere to producer of originally designed aircraft. Emphasizing aerodynamic cleanliness, they designed the SLD (for "Stiavelli-Luzzatti-Ducrot"), a single-seat biplane fighter powered by the 149-kilowatt (200-horsepower) Hispano-Suiza 35 engine driving a two-bladed propeller. It had a plywood monocoque fuselage of oval section. The undercarriage struts extended through the lower wing to carry the fuselage above the lower wing.