Voisin X

Voisin X/10/LAR/LBR/E.54
Role	Night Bomber & Reconnaissance
Manufacturer	Voisin
Designer	Gabriel Voisin
First flight	1917
Introduction	1917
Primary user	France Aéronautique Militaire
Number built	approx 900 LAR & LBR built.
Developed from	Voisin VIII

The Voisin X was a French two-seat biplane pusher which was built in two versions, one fitted with a 37mm Hotchkiss cannon (the LBR or Ca.2), and the other as a conventional night bomber (the LAR or Bn.2). Problems with the Peugeot engine in the previous Voisin VIII led to the installation of a new Renault engine of greater power and reliability, but the new aircraft was otherwise nearly identical to the VIII. Despite its obsolescence, it would make up the bulk of front line night bomber escadrilles until the end of the war.

Development

With the failure of the 1915 and 1916 bomber contests to produce any usable types to replace the Voisin V, Voisin was asked to produce an interim type pending the development of the next generation of bombers. This began with the Voisin VII which was itself an enlarged V, but was underpowered, and was soon followed by the Voisin VIII, which suffered severe reliability problems. As with the VIII, two versions were to be built, a night bomber, and an aircraft armed with a large single shot 37mm Hotchkiss cannon . By the time the X appeared, the cannon had been found to be of little use and most of those built as LBR/Ca.2s were converted to bombers with the cannons removed. Those LBRs still fitted with the cannon had the pilot in the rear seat, while in the LAR, the pilot sat in the front seat, while the rear occupant could be equipped with a light machine gun such as a Lewis. On some aircraft, the observer's gun was mounted on a ring that was inclined forward to make movement forward easier against the wind.

Like the previous Voisins going back to the Voisin III, the Voisin VIII had a steel tube structure to provide adequate strength, covered with aluminium sheet on the fuselage nacelle and doped fabric on the flying surfaces. The fuselage was a square box to which no attempt was made at reducing drag. The 3-bay wings had a constant chord and square tips, and the top wings were slightly longer than the lower wings. The cruciform tail was mounted on booms that tapered in plan view only to a vertical knife edge that formed the rudder post. The all-flying rudder and elevator were aerodynamically balanced and had no fixed flying surfaces. Unusually for the period, and because it had no skid to drag it to a stop, it was equipped with drum brakes on the rear wheels. Like the Voisin VIII, the X was fitted with two large strut mounted teardrop fuel tanks that could be jettisoned in the event of a fire. Also, as with the VIII, the X was usually fitted with tall individual exhaust stacks projecting above the top wing. Due to the change from a V-8 to a V-12 there were additional stacks, and some examples had a muffler installed. A small additional aerodynamic counterbalance was sometimes also added at the bottom of the rudder.

Operational history

Aerochir

While the British and Americans experimented with aerial ambulances, carrying a single stretcher in a Curtiss Jenny or Airco DH.4, in France, a Voisin X was converted into a complete mobile flying hospital, the Aerochir, complete with X-ray machines and other modern equipment for a full service operating room, so as to better support the mobile battlefield conditions created by the introduction of tank warfare.

Drone/autopilot

In 1918, a Voisin X made a fully automated 100km flight without human assistance. A pilot was carried as a backup but wasn't found to be necessary. Four Sperry gyroscopes actuated electrical servo motors which controlled the flight surfaces and the engine throttle. During the flight, it changed altitude and direction multiple times, based on a preprogrammed course set with a series of switches. Testing resumed in 1923, for intended use as an auto-pilot.

French service

The first Voisin X's entered service with VB114 in late 1917.

Beginning in July 1918, the Voisin was supplemented by the Farman F.50 in French front-line service, with surviving examples being transferred to newly created second line units.

Variants

Fuselage to a Voisin X/LBR at the Musée de l'air et de l'espace showing the 37 mm (1.457 in) cannon

Voisin X

• 280 hp (210 kW) Renault 12Fe
  • Voisin LAR - factory designation for X night bomber
  • Voisin LBR - factory designation for X armed with 37 mm (1.457 in) cannon

Voisin XI

• Variant of X with 350 hp (260 kW) Panhard 12Bc and minor changes to proportions but only around 10 built

Operators

France

• Aéronautique Militaire
  • Night Reconnaissance
    • Escadrille VR290 (8th Escadrille 4th RAO postwar)
    • Escadrille VR291
    • Escadrille VR292
    • Escadrille VR293
    • Escadrille VR294
    • Escadrille VR295
    • Escadrille VR296
  • Bombing
    • Group de Bombardment 1 (GB 1)
      • Escadrille V25
      • Escadrille VC110
      • Escadrille VB114
      • Escadrille VC116
      • Escadrille VB135
      • Escadrille VB136
      • Escadrille VB137
    • Group de Bombardment 3 (GB 3)
      • Escadrille VB109
      • Escadrille VB113
    • Group de Bombardment 7 (GB 7)
      • Escadrille VR118
      • Escadrille VR119
      • Escadrille VR121
    • Group de Bombardment 8 (GB 8)
      • Escadrille VB109
      • Escadrille VC116
      • Escadrille VB125
    • Group de Bombardment 9 (GB 9)
      • Escadrille VB125 (briefly)
    • Group de Bombardment 10 (GB 10)
      • Escadrille VB101
      • Escadrille VC116
      • Escadrille VB133
    • Group de Bombardment 51 (GB 51)
      • Escadrille VB135
      • Escadrille VB136
      • Escadrille VB137
      • Escadrille VR293
  • Théâtres d'Opérations Extérieurs (TOE) Overseas Threatres (mostly North Africa)
    • Escadrille VR541
    • Escadrille VR542
    • Escadrille VR543
    • Escadrille VR547
    • Escadrille VR551
    • Escadrille VR552
    • Escadrille VR553
    • Escadrille VR554
    • Escadrille VR555
    • Escadrille VR556
    • Escadrille VR557
    • Escadrille VR558
    • Escadrille VR571

Czechoslovakia

• four examples used by 4 Letecka Setnina and Letecke Dilny, both at Cheb postwar.

United States

• American Expeditionary Force operated two examples as trainers in 1919.

Survivors/Aircraft on display

• Musée de l'air et de l'espace has a fuselage of a Voisin X/LBR equipped with a cannon.

Specifications

Voisin 10 3 view plan

Data from French Aircraft of the First World War

General characteristics

• Crew: 2
• Length: 10.35 m (33 ft 11 in)
• Wingspan: 17.90 m (58 ft 9 in)
• Height: 3.95 m (13 ft 0 in)
• Wing area: 61.14 m² (658.1 sq ft)
• Empty weight: 1,400 kg (3,086 lb)
• Max takeoff weight: 2,200 kg (4,850 lb)
• Propellers: 2-bladed Lumière fixed-pitch pusher propeller

Performance

• Maximum speed: 135 km/h (84 mph, 73 kn) @ 2,000 m (6,600 ft)
• Range: 350 km (220 mi, 190 nmi)
• Endurance: 5 hours
• Time to altitude: 20 minutes to 2,000 m (6,600 ft)

Armament

• LAR equipped with one machine gun and 300 kg (660 lb) of bombs.
• LBR equipped with a 37 mm (1.457 in) Hotchkiss cannon

See also

Aircraft of comparable role, configuration, and era

• Breguet Bre.12
• Farman F.40
• Royal Aircraft Factory FE.2
• Savoia-Pomilio SP.3

Related lists

• List of bomber aircraft
• List of pusher aircraft by configuration
• List of military aircraft of France
• List of military aircraft of the Entente Powers in World War I

Further reading

• Woodman, Harry (1989). Early Aircraft Armament: The Aeroplane and the Gun Up to 1918. London, UK: Arms & Armour Press. ISBN 978-0853689904.
• Template:Fr icon Official rigging manual

Bibliography

• Davilla, Dr. James J.; Soltan, Arthur (1997). French Aircraft of the First World War. Mountain View, CA: Flying Machines Press. ISBN 978-1891268090.
• Template:Fr icon de Fouchier, Arnauld (1978). "Un Voisin sans pilot en 1918". L'Enthousiaste. 5 (July/August). Editions E.P.A.: 1–4.
• Template:Fr icon Voisin series of aircraft aviafrance.com