Wibault 3

The Wibault 3, also known as the Wibault Wib 3 C.1, was a French prototype fighter aircraft from the 1920s featuring a parasol wing configuration, specifically engineered for operations at high altitudes. Its development was discontinued following persistent failures in the supercharger materials.

Design and development

The Wib 3 C.1 (Chasseur, indicating a single-seat fighter) was created by Wibault in response to the Service Technique de l'Aéronautique (S.T.Aé) requirement for a fighter capable of high-altitude performance. The design brief demanded a maximum speed of at an altitude of and a service ceiling reaching , achievable through the use of a turbocharged powerplant.

Its airframe was built around a duralumin framework, predominantly covered with fabric. The parasol wing included a cut-out section along the trailing edge above the open cockpit to enhance pilot visibility. This wing had straight edges with a constant chord and extended-span ailerons, supported by faired struts connecting to the lower fuselage. The wing’s thickness gradually diminished toward the tips, resulting in an optimal lift to drag ratio close to 20.

The aircraft was powered by an upright water-cooled V-8 Hispano-Suiza 8F engine, cooled via Lamblin cylindrical radiators positioned on both sides of the enclosed engine cowling. A Rateau supercharger was designed to sustain engine output up to . The fuselage featured an aluminium skin at the front section with fabric covering toward the rear. Its tail assembly consisted of a wire-braced tailplane with split elevators that had trimmed inner edges to allow rudder movement. The fixed conventional undercarriage comprised main wheels mounted on a rigid axle, supported by V-shaped struts, and included an aerofoil fairing that contributed an additional to the wing area.

On its maiden flight in early 1923, the Rateau turbo-supercharger was absent due to setbacks caused by failures in high-temperature alloys. These issues led S.T.Aé to terminate the project. Nonetheless, flight trials proceeded until autumn of that year, ending when the requirement for high-altitude capabilities was revoked.