The Wibault 12 Sirocco or Wib 12 Sirocco was a two-seat,

parasol wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

designed and built in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

in the 1920s. Three fighter prototypes were completed, one for the RAF and two Army co-operation variants. There was no series production.

Design

The Wib 12 Sirocco, a single engine, two seat, parasol wing fighter was a structurally much revised development of the similarly configured Wib 8 Simoun, following it through the Avions Marcel Wibault works with less than a month between their maiden flights. They were externally very similar but the more refined structure of the Wib 12 made it both stronger and 12% lighter than its predecessor. One major change was the replacement of the Wib 8's box

spars SPARS was the authorized nickname for the United States Coast Guard (USCG) Women's Reserve. The nickname was derived from the USCG's motto, "—"Always Ready" (''SPAR''). The Women's Reserve was established by law in November 1942 during Wor ...

with ones of I-section. The general design followed that of Wibault's family of single- and two-seat fighters, the Wib 3, Wib 7, Wib 8 and Wib 9 but in external detail was closest to the Wib 8. It was an all-metal aircraft, the structure mostly

Duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium–copper alloys. The term is a combination of ''Düren'' and ''aluminium'' ...

and covered with narrow aluminium strips applied longitudinally. The parasol wing was straight edged and of constant chord, braced to the lower

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

with a pair of parallel

strut A strut is a structural component commonly found in engineering, aeronautics, architecture and anatomy. Struts generally work by resisting longitudinal compression, but they may also serve in tension. A stay is sometimes used as a synonym for ...

s on each side which met the wing at about mid-span. The Wib 12 had a new pair of

jury strut In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of struts, which act in ...

s from the main wing struts to the wing underside for strengthening. There were

cabane strut In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of struts, which act in ...

s over the fuselage and a

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

cut-out in the wing over the pilot's

cockpit A cockpit or flight deck is the area, on the front part of an aircraft, spacecraft, or submersible, from which a pilot controls the vehicle. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls th ...

to enhance his visibility. A pair of synchronised

Vickers machine gun The Vickers machine gun or Vickers gun is a Water cooling, water-cooled .303 British (7.7 mm) machine gun produced by Vickers Limited, originally for the British Army. The gun was operated by a three-man crew but typically required more me ...

s fixed to the fuselage fired forwards through the

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

arc; in addition the rear cockpit was fitted with a pair of Lewis guns of the same calibre on a

Scarff ring The Scarff ring was a type of machine gun mounting developed during the First World War by Warrant Officer (Gunner) F. W. Scarff of the Admiralty Air Department for use on two-seater aircraft. The mount incorporated bungee cord suspension in el ...

. A braced

tailplane A tailplane, also known as a horizontal stabilizer, is a small lift (force), lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters ...

was mounted towards the top of the fuselage, together with an angular

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. F ...

and

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...

. The Wib 12's engine, the same water-cooled V-12 Hispano-Suiza 12Hb type as used by the Wib 8, was totally enclosed and drove a two blade propeller. It was cooled by a retractable, half-cylindrical

radiator A radiator is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

on the fuselage underside at the back of the engine. Behind the engine the fuselage was flat sided. The fighter had a fixed

conventional undercarriage Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Ter ...

with mainwheels on a split axle attached to the fuselage underside, supported by a pair of V-struts; there was a small tailskid. The Wib 12 and the Wib 121 (the first and second prototypes) were both flown for the first time in May 1926. The latter was about 8% faster in a climb to 4,000 m (13,125 ft) than the heavier Wib 8. The third aircraft, the Wib 122 was built for

Vickers Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 18 ...

aircraft, with whom Wibault shared patents and collaborative designs. They fitted it with a W-12

Napier Lion XI The Napier Lion is a 12-cylinder, petrol-fueled 'broad arrow' W12 configuration aircraft engine built by D. Napier & Son from 1917 until the 1930s. A number of advanced features made it the most powerful engine of its day and kept it in pro ...

engine and knew it as the Vickers Type 127. To avoid the central bank of cylinders the Vickers guns were moved from the fuselage top to the sides. Its test programme was interrupted by continual engine overheating problems. When the Service Technique de l'Aéronautique (S.T.Aé, Technical Department of Aeronautics) cancelled the two seat fight specification in 1926, further development by Wibault also ended; though the Wib 121 went on a sales demonstration in

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in 1928, no orders were gained. Instead, the company tried to develop the design into a two-seat Army cooperation reconnaissance aircraft. The Wib 124 had its armament modified, having no wing guns and only one fuselage mounted synchronised

, but with an added ventral Lewis gun. The Wib 125 had the same armament but was powered by a Renault 12Jc water-cooled V-12 engine. Again, no orders resulted.

Variants

C=Chasseur (fighter); A=Army; 2=two-seater. One of each only. ;Wib 12 Sirocco C.2: First prototype, fuselage and rear seat guns only. ;Wib 121 Sirocco C.2: Second prototype, wing guns added. ;Wib 122 Sirocco C.2: One aircraft built as the Vickers Type 127. ;Wib 124 A.2: Army co-operation version. No wing guns and only one synchronised Vickers gun in upper fuselage but a ventral Lewis gun added. ;Wib 125 A.2: Army co-operation version. Renault 12Jc water-cooled V-12 engine, same armament as Wib 124. ;Vickers Type 127 :\the single Wib 122 Sirocco C.2 built for

, who replaced the Hispano engine with a W-12

. Vickers referred to it as the Vickers Type 127; its RAF serial was ''J9029''.

Specifications (Wib 121 C.2)

References

{{Wibault aircraft Parasol-wing aircraft 1920s French fighter aircraft Wib 12 Single-engined tractor aircraft