SPAD S.XII Biplane Fighter Aircraft

The cannon-armed SPAD S.XII was produced in only 300 examples with many of these reserved for experienced pilots.

Updated: 11/20/2015; Authored By Staff Writer; Content ©www.MilitaryFactory.com

French flying ace Georges Guynemer pushed the idea of a cannon-armed fighter plane after his experiences in aircraft such as the SPAD S.VII. This led the Societe Pour l'Aviation et ses Derives (SPAD) company to develop such a system. The follow-up design came to be known as the S.XII (or S.12) and featured a 37mm cannon along with its standard single machine gun armament.

Externally, the SPAD S.XII looked every bit as a further development of the SPAD S.VII model. Due to the extra weight imposed on the airframe by the new cannon armament, the fuselage was lengthened over that of the S.VII. A Hispano-Suiza engine was once again used by SPAD and consisted of the 8Bc or 8Bec types, each offering 220 horsepower. What made the 8Bec unique was that the 37mm cannon could be nestled between the cylinder banks. Subtle changes to the wings were also necessitated by the increase in weight.

First flight for the SPAD S.XII was achieved on July 5th, 1917 with limited production examples following. The system proved a handful for the inexperienced but lethal in the hands of a proven military aviator. As the cannon system extended into the cockpit, the aircraft was not controlled through a traditional flight stick. Additionally, reloading the cannon while flying the plane added another responsibility while in-flight. The standard single 7.7mm Vickers machine gun remained a part of the offensive toolbox for the S.XII, a carry-over from the S.VII design.

Though the cannon-mounted SPAD S.XII's initially proved successful, they really required an experienced pilot at the controls of both aircraft and armament. With more and more resources being dedicated to the already proven S.VII and S.XIII designs, the S.XII was limited to a mere 300 production examples and, as such, the system never equipped an entire unit. In any case, the idea of a cannon-armed aircraft was intriguing and perfected to the extreme in the Second World War and beyond.

Like the SPAD S.VII before it and the SPAD S.XIII after it, the SPAD S.XII was designed by Louis Bechereau.

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SPAD S.XII Technical Specifications

Service Year: 1917
Type: Biplane Fighter Aircraft
National Origin: France
Manufacturer(s): Societe Pour l'Aviation et ses Derives (SPAD) - France
Production Total: 300

Structural (Crew Space, Dimensions and Weights)

Operating Crew (Typical): 1
Overall Length: 21.00 feet (6.4 meters)
Overall Width: 26.25 feet (8.00 meters)
Overall Height: 8.37 feet (2.55 meters)

Weight (Empty): 1,294 lb (587 kg)
Weight (MTOW): 1,947 lb (883 kg)

Installed Power and Standard Day Performance

Propulsion: 1 x Hispano-Suiza HS 8Bc engine developing 220 horsepower OR 1 x Hispano-Suiza HS 8Bec engine developing 220 horsepower.

Maximum Speed: 126 mph (203 kph; 110 knots)
Maximum Range: 217 miles (350 km)
Service Ceiling: 22,474 feet (6,850 meters; 4.26 miles)
Rate-of-Climb: 1,090 feet-per-minute (332 m/min)

Armament / Mission Payload

STANDARD:
1 x 7.7mm Vickers machine gun

Some with HS 8Bec engines featured a 1 x 37mm Puteaux cannon mounted between the cylinder banks.

Global Operators / Customers

France; Imperial Russia; Serbia; United Kingdom; United States; Yugoslavia

Model Variants (Including Prototypes)

S.XII - Base Series Designation