Wibault 12 Sirocco
| Company type | Fighter aircraft prototype |
|---|---|
| Industry | Aviation |
| Founded | 1920s |
| Products | Military aircraft |
The Wibault 12 Sirocco, also referred to as Wib 12 Sirocco, was a French-designed, two-seat parasol wing fighter aircraft developed during the 1920s. A total of three prototypes were constructed: one intended for the RAF and two designed for Army cooperation roles. No mass production followed these initial builds.
Design
As a single-engine, two-seat parasol wing fighter, the Wib 12 Sirocco represented an evolution of the similarly configured Wib 8 Simoun, with their maiden flights occurring less than a month apart. While outwardly alike, the Wib 12 incorporated structural enhancements that resulted in a stronger frame that was also approximately 12% lighter, achieved by substituting the Wib 8’s box spars with I-section spars.
Continuing the lineage of Wibault’s series of single- and two-seat fighters (Wib 3, Wib 7, Wib 8, and Wib 9), the Wib 12 was constructed entirely from metal, mainly Duralumin, and sheathed with longitudinal aluminium strips. Its parasol wing featured straight edges and a constant chord, supported by parallel struts connecting to the lower fuselage on each side, supplemented by jury struts for added rigidity. The wing was mounted above the fuselage on cabane struts and included a trailing edge cut-out above the pilot’s cockpit to enhance visibility. Armament consisted of two fuselage-mounted, synchronised Vickers machine guns firing through the propeller arc, complemented by two rearward-facing Lewis guns mounted on a Scarff ring. The tail assembly was braced and positioned high on the fuselage, with an angular fin and rudder design.
The powerplant was a water-cooled V-12 Hispano-Suiza 12Hb engine—the same model used in the Wib 8—fully enclosed within the cowling and turning a two-blade propeller. Engine cooling was managed by a retractable half-cylindrical radiator located beneath the rear section of the engine. The fuselage had flat sides and featured a fixed conventional undercarriage with split-axle main wheels supported by V-struts and a small tailskid.
The initial two prototypes—the Wib 12 and Wib 121—conducted their first flights in May 1926; notably, the Wib 121 achieved an ascent to 4,000 m (13,125 ft) that was approximately 8% faster than the heavier Wib 8. The third prototype, designated Wib 122 and built for Vickers, was fitted with a Napier Lion XI engine and became known as the Vickers Type 127. To accommodate this W-12 engine's central bank of cylinders, Vickers relocated the machine guns to either side of the fuselage. However, ongoing issues with engine overheating limited its flight testing.
Following the cancellation of the two-seat fighter requirement by France's Service Technique de l'Aéronautique (S.T.Aé) in 1926, development efforts were halted. Despite demonstrations of the Wib 121 in Turkey in 1928, no procurement contracts were secured. Subsequently, Wibault adapted this design for reconnaissance missions in Army cooperation roles:
- The Wib 124 variant eliminated wing-mounted guns in favor of one synchronised Vickers gun installed on the fuselage plus a ventral Lewis gun.
- The Wib 125 maintained this armament configuration but was powered by a Renault 12Jc water-cooled V-12 engine.
Neither model succeeded in obtaining production orders.
Variants
C=Chasseur (fighter); A=Army; 2=two-seat configuration. Only one unit of each type was produced.
- Wib 12 Sirocco C.2
- Initial prototype featuring armament limited to the fuselage and rear cockpit.
- Wib 121 Sirocco C.2
- Second prototype, enhanced with additional guns mounted on the wings.
- Wib 122 Sirocco C.2
- A single machine constructed and identified as the Vickers Type 127.
- Wib 124 A.2
- Version designed for army cooperation, equipped without wing-mounted guns but fitted with a synchronized Vickers gun in the upper fuselage and a ventral Lewis gun.
- Wib 125 A.2
- Army cooperation model powered by a Renault 12Jc water-cooled V-12 engine, maintaining the same weaponry as the Wib 124.
- Vickers Type 127
- \the sole Wib 122 Sirocco C.2 produced for Vickers, which replaced the original Hispano engine with a W-12 Napier Lion XI. Vickers assigned it the designation Vickers Type 127; RAF serial number J9029.