SPAD S.XII

The SPAD XII 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 VII design as the starting point, but the many major and minor changes incorporated into the SPAD XII made it a quite different aircraft.

File:Hispano Suiza 8Ca.jpg

File:Hispano-Suiza 8C (MAE).JPG to clear the 37mm cannon mounted in the "vee" between the cylinder banks.]]

The gun chosen for the SPAD XII 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, avoiding the problem of firing through the moving blades. The SPAD XII also carried a single 0.303 inch synchronized (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 with a hollow propeller shaft for the cannon to fire through, and power the airframe, weighing {{convert|587|kg|lb}} rather than the {{convert|500|kg|lb}} of the SPAD VII, the 180 bhp Hispano-Suiza 8 direct-drive Ab engine was replaced by the geared 220 bhp model 8Cb, which also gave the SPAD XII a clockwise (seen "nose-on") rotating propeller.

Test-flown by Guynemer, the early production models of the SPAD XII were highly successful after overcoming initial problems with the reduction gear between engine and propeller.{{cite book |title=SPAD XII/XIII aces of World War I |pages= 7, 9 }} Other aces also had success with the new model. However, deliveries were slow, the SPAD VII and later SPAD XIII having top priority, and even the modest total of 300 aircraft which were ordered were not all completed.{{Citation needed|date=May 2010}} Best estimates are only 20 produced. Average pilots found the SPAD XII 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. The cannon's breech mechanism protruded into the cockpit and prevented the use of a conventional stick to control the aircraft, adding to pilots' difficulties. The control setup reverted to a split setup on either side of the pilot, a la Deperdussin.{{cite book |title=SPAD XII/XIII aces of World War I |pages=8–9 }}

File:13th Aero Squadron - Salmson 2A2-3.jpg

No units were entirely equipped with SPAD XIIs.{{Citation needed|date=May 2010}} 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.{{cite book |title=SPAD XII/XIII aces of World War I |pages= 9–10 }} Few were delivered to combat units, eight being recorded on strength in April and again in October; this may be contrasted with the thousands of SPAD VIIs and SPAD XIIIs in service. Single examples for testing were delivered to the Royal Flying CorpsBruce 1982, p. 560. and one to the Aviation Section of the American Expeditionary Force, with the AEF's 13th Aero Squadron receiving the code "0", it was primarily flown by the 13th's Charles John Biddle.{{cite book |title= SPAD XII/XIII Aces of World War I |first= Jon |last=Guttman |publisher= Osprey Publishing |year= 2002 |isbn= 978-1-84176-316-3 |pages= 12, 14–15 }}

;{{FRA}}

• French Air Force

;{{RUS}} / {{USSR}}

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

;{{flag|Serbia}}

• Serbian Air Force

;{{UK}}

• Royal Flying Corps - One aircraft only.

;{{USA}}

• American Expeditionary Force - One aircraft only, serving with 13th Aero Squadron.

;{{flag|Kingdom of Yugoslavia}}

• Yugoslav Royal Air Force - Postwar

{{Aircraft specs

|ref=The Complete Book of Fighters Green and Swanborough 1994, pp. 542–543.

|prime units?=met

|crew=1

|length m=6.4

|length note=

|span m=8

|span note=

|height m=2.55

|height note=

|wing area sqm=20.2

|wing area note=

|aspect ratio=

|airfoil=

|empty weight kg=587

|empty weight note=

|gross weight kg=883

|gross weight note=

|max takeoff weight kg=

|max takeoff weight note=

|fuel capacity=

|more general=

|eng1 number=1

|eng1 name=Hispano-Suiza 8Cb

|eng1 type=V-8 water-cooled piston engine

|eng1 kw=164

|eng1 note=

|prop blade number=2

|prop name=fixed-pitch propeller

|prop dia m=

|prop dia note=

|max speed kmh=203

|max speed note=

|cruise speed kmh=

|cruise speed note=

|stall speed kmh=

|stall speed note=

|never exceed speed kmh=

|never exceed speed note=

|range km=

|range note=

|combat range km=

|combat range note=

|ferry range km=

|ferry range note=

|endurance=1 hour 45 minutes

|ceiling m=6850

|ceiling note=

|g limits=

|roll rate=

|climb rate ms=

|climb rate note=

|time to altitude={{cvt|2000|m}} 6 minutes 3 seconds

|wing loading kg/m2=

|wing loading note=

|fuel consumption kg/km=

|power/mass=

|more performance=

|guns=1 x 37 mm Puteaux single shot cannon, 1 x .303 in (7.7 mm) Vickers machine gun

}}

{{aircontent

||related=

• SPAD S.VII
• SPAD S.XI
• SPAD S.XIV
• De Bruyère C 1

|similar aircraft=

|sequence=

}}

{{Commons category}}

{{Reflist}}

• Bruce, J. M. The Aeroplanes of the Royal Flying Corps (Military Wing). London: Putnam, 1982. {{ISBN|0-370-30084-X}}.
• {{cite journal |last1=Cony |first1=Christophe |title=Le Spad XII Canon (1^re partie) |journal=Avions: Toute l'aéronautique et son histoire |date=January 1995 |issue=23 |pages=39–42 |trans-title=The Canon-armed SPAD XII |language=French |issn=1243-8650}}
• 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.

{{SPAD aircraft}}

{{Authority control}}

Category:1910s French fighter aircraft

S.XII

Category:Aircraft first flown in 1917

Category:Biplanes

Category:Single-engined tractor aircraft