Blériot-SPAD S.81

The Blériot-SPAD S.81 (S.81 C.1) was a French fighter aircraft developed in 1923 to a requirement by the French Air Force. It was flown competitively against the Dewoitine D.1 and was selected over that aircraft due to the Dewoitine's more radical design, leading to an order for 80 aircraft. The S.81 was a single-bay biplane of conventional configuration with I-shaped interplane struts and lacking Herbemont's usual swept upper wing. It featured a wooden fuselage of monocoque construction and metal wings skinned in fabric. Production versions differed from the prototypes in having a lengthened fuselage and larger tail fin.

Variants

 * S.81.01:two prototypes, powered by a 300 hp Hispano-Suiza 8Fb V-8 engine. The second aircraft was used for static tests only


 * S.81/1:production version, powered by a 300 hp Hispano-Suiza 8Fb V-8 engines, designated S.81 C.1 (S.81 Chasseur - single-seater) in air force service.


 * S.81bis:single example of racer version developed for the Coupe Michelin race. Performance poor.


 * S.81/2:single machine to evaluate alternative radiator design.


 * S.81/3:single machine to evaluate alternative radiator design


 * S.81/4:single machine to evaluate wooden wing design


 * S.81/6:racer converted from the S.81-bis

Operators

 * French Air Force
 * 2ème Fighter Regiment
 * 2ème Fighter Regiment