SPAD S.XII

SPAD S.XII
Role	biplane cannon-armed fighter
National origin	France
Manufacturer	SPAD
Designer	Louis Béchereau
First flight	5 July 1917
Primary users	Aéronautique Militaire Red Army
Number built	unknown, 300 ordered
Developed from	Spad S.VII

The SPAD S.XII or SPAD 12 was a French single-seat biplane fighter aircraft of the First World War developed from the successful SPAD 7 by Louis Béchereau, chief designer of the Société Pour L'Aviation et ses Dérivés (SPAD).

Development

The SPAD 12 was inspired by the ideas of French flying ace Georges Guynemer, who proposed that a manoeuvrable single-seat aircraft be designed to carry a 37 mm cannon, a weapon which had previously been mounted only in large two-seat "pusher" aircraft such as the Voisin III. Béchereau took his own SPAD 7 design as the starting point, but the many major and minor changes incorporated into the SPAD 12 made it a quite different aircraft.

The gun chosen for the SPAD 12 was not the old Hotchkiss cannon but a new 37 mm Semi Automatique Moteur Canon (SAMC), built by Puteaux, for which 12 shots were carried. The Hispano-Suiza aviation engine had to be geared to allow the gun to fire through the propeller shaft. The SPAD 12 also carried a single 0.303 inch (7.7 mm) Vickers machine gun mounted on the starboard side of the nose. In order to carry the heavy cannon the airframe was lengthened and the wingspan and wing area increased. The wingtips were rounded rather than squared off and the wings given a slight forward stagger. To accommodate the required geared output propshaft engine, which easily allowed for the hollow propeller shaft for the cannon to fire through, and power the resultingly heavier airframe, 587 kg compared to the 500 kg of the SPAD 7, the 180 bhp Hispano-Suiza 8 direct-drive Ab engine was replaced by the geared 220 bhp model 8Cb, and gave the SPAD XII a clockwise rotating propeller, as seen from a "nose-on" view.

Test flown by Guynemer, the early production models of the SPAD 12 were highly successful after overcoming initial problems with the reduction gear between engine and propeller. Other aces also had success with the new model. However, deliveries were slow, the SPAD 7 and later SPAD 13 having top priority, and even the modest total of 300 aircraft which were ordered were not all completed.^{[citation needed]} Best estimates are only 20 produced. Average pilots found the SPAD 12 a difficult aircraft to master, and the cannon difficult to aim and fire, while manual reloading was difficult. The cockpit filled with fumes upon every firing. Its breech mechanism protruded into the cockpit and prevented the use of a conventional stick to control the aircraft, adding to the difficulties encountered by ordinary pilots. The control setup reverted to a split setup on either side of the pilot, a la Deperdussin.

Service

No units were entirely equipped with SPAD 12s.^{[citation needed]} The unknown number of aircraft produced were issued in small numbers, intended for use only by the most skilled pilots, such as Rene Fonck, Lionel de Marmier, Fernand Henri Chavannes, Henri Hay de Slade, Albert Deullin and François Battesti. They were distributed one or two per squadron. Few were delivered to combat units, 8 being recorded on strength in April and again in October; this may be contrasted with the thousands of SPAD 7s and SPAD 13s in service. Single examples for testing were delivered to the Royal Flying Corps and one to the Aviation Section of the American Expeditionary Force, and reportedly the AEF's 13th Aero Squadron got the aircraft, which was given the number "0", and primarily flown by the 13th's Charles John Biddle [1], who ended up with a total of seven confirmed victories in World War I. Six or more are said to have been held by the Red Army.^{[citation needed]}

Operators

France

Russia / Soviet Union

• Imperial Russian Air Force
• Soviet Air Force - Postwar.

Serbia

United Kingdom

• Royal Flying Corps - One aircraft only.

United States

• American Expeditionary Force - One aircraft only.

Kingdom of Yugoslavia

• Yugoslav Royal Air Force - Postwar

Specifications (S.XII)

Data from The Complete Book of Fighters

General characteristics

• Crew: 1
• Length: 6.40 m (21 ft 0 in)
• Wingspan: 8.00 m (26 ft 3 in)
• Height: 2.55 m (8 ft 4½ in)
• Wing area: 20.2 m² (217 ft²)
• Empty weight: 587 kg (1,295 lb)
• Loaded weight: 883 kg (1,947 lb)
• Max. takeoff weight: 834 kg (1,840 lb)
• Powerplant: 1 × Hispano-Suiza 8Cb V-8 water-cooled engine, 164 kW (220 hp)

Performance

• Maximum speed: 203 km/h (110 knots, 126 mph)
• Endurance: 1¾ hr
• Service ceiling: 6,850 m (22,470 ft)
  
• Climb to 2,000 m (6.560 ft): 6 min 3 sec

Armament

• Guns: 1 x 37 mm Puteaux single shot cannon, 1 x 7.7 mm Vickers machine gun

See also

• SPAD S.VII
• SPAD S.XI
• SPAD S.XIV

References

Notes

Bibliography

• Taylor, John W. R., and Jean Alexander. "Combat Aircraft of the World" New York: G.P. Putnam's Sons, 1969 Library of Congress Catalog Card Number 68-25459 (Pg.127)
• Bruce, J.M. The Aeroplanes of the Royal Flying Corps (Military Wing). London:Putnam, 1982. ISBN 0-370-30084-X.
• Davilla, James J., & Soltan, Arthur M., French Aircraft of the First World War. Stratford, Connecticut: Flying Machines Press, 1997. ISBN 0-9637110-4-0.
• Green, William and Swanborough, Gordon. The Complete Book of Fighters. New York: Smithmark, 1994. ISBN 0-8317-3939-8.
• Guttman, Jon, SPAD XII/XIII aces of World War I. Osprey Publishing, 2002. ISBN. 1841763160, 9781841763163.