J.Davilla, A.Soltan French Aircraft of the First World War (Flying Machines)

SPAD 18

  The SPAD 18 was a large single-seat monocoque design with a 300-hp Hispano-Suiza 8G fitted with a 37-min Putueax cannon firing through a hollow hub. However, it was found that because of excessive vibration the Hispano-Suiza 8G was unusable. The airframe ol the SPAD 18 (which was apparently never equipped with the cannon) was fitted with a version of the 300-hp Hispano Suiza 8Fb engine that did not have a cannon. This aircraft was designated the SPAD 20. The SPAD 18 had the option of a rear gunner, hence the Ca.1-2 designation.


SPAD 18 Single-Seat or Two-Seat Fighter with 300-hp Hispano-Suiza 8G (never fitted)
   Span 9.70 ni; length 7,30 m; height 2.80 in; wing area 10 sq. in
   Intended armament was a 37-mm Putueax cannon (never fitted)
   One built (but never flown with Hispano-Suiza 8G)



SPAD 20

  The SPAD 20 was produced in response to the C2 requirement of 1918 calling for a crew of two, a useful load of 375 kg, a maximum ceiling of 8,000 m, a service ceiling of 5,000 m, and a maximum speed of 220 km/h. The aircraft offered in the C2 category included the SEA 4, the Hanriot-Dupont HD.3, and the SPAD 20.
  The SPAD 20 was developed from the SPAD 18, which had failed because the Hispano-Suiza engine fitted with a cannon had proved unsuccessful. The SPAD 20 incorporated many of the features that Herbemont would include in his postwar designs. These included a monocoque fuselage of molded wood, an upper wing which had a slight sweepback, a straight lower wing fitted with ailerons, thick I-shaped interplane struts, and wooden construction with fabric covering. The tail surfaces were quite large and the tail section was molded in the same way as the fuselage. The engine was a 300-hp Hispano-Suiza 8Fb. A notable feature was that the engine attachments were designed so that it was easily accessible and could be removed quickly in the field. The fuel tanks were protected to prevent fire from breaking out should they be damaged.
  Because single-seat aircraft were vulnerable to attack from the rear, the C2 requirement called for a rear gunner. On the SPAD 20 the gunner was provided with one 7.7-mm Vickers machine gun on a T.O.3 mounting, although on early examples a Lewis gun was used. The pilot had two synchronized 7.7-mm Vickers machine guns.
  On 7 August 1918, the SPAD 20 was flown by test pilot Sadi Lecointe at Buc airfield. During testing Lecointe set a world altitude record of 8,900 meters. By the beginning of September the prototype was sent to the CIACB at Villacoublay for military trials. These revealed some shortcomings, and changes were mandated for the armament and the fuel tanks. After these modifications, the STAe ordered 300 SPAD 20s. However, after the war ended the order was reduced (on 2 October 1920) to 100, of which 95 were actually delivered.
  The aircraft delivered in 1920 were armed with two synchronized Vickers machine guns and a single Lewis gun on a ring mount. The performance was comparable to the single-seat Nieuport 29s then in service.
  One major variant was the SPAD 20bis, which had twin rear guns. The wing surface area was augmented by 1.50 square meters and the fin and rudder were enlarged slightly to compensate for the additional rear gun. The first flight took place on 7 July 1921. Two prototypes were constructed, but development was not pursued.
  The SPAD 20s were flown before delivery at Bourget by four pilots drawn from the 1st and 2nd Aviation Regiments. They praised the machine's maneuverability and rapid climb. The aircraft served with the 2nd Air Regiment at Strasbourg, the 32nd Regiment Mixte at Dijon (5th and 6th Escadrilles, fighter units assigned to the Groupe d'Chasse), the 3rd Regiment d'Aviation de Chasse at Chateauroux, which consisted of the 1st Groupe d'Chasse (1st, 2nd, and 3rd Escadrilles), and the 2nd Groupe d'Chasse (5th, 6th, and 7th Escadrilles).


Foreign Service

Japan
  A pair of SPAD 20bis were sold to the Japanese, who dissected them to learn the latest French manufacturing techniques. They were designated Hei 2.

Paraguay
  A few SPAD 20s were reportedly obtained by Paraguay postwar. These were used during the 1922 civil war.


SPAD 20 Prototype with 300-hp Hispano-Suiza (Data Refers To Performance When Flown as a Single-Seater)
   Span 9.7720 m; length 7.200 m; height 2.87 m; wing area 30 sq. m
   Empty weight 850 kg; loaded weight 1,310 kg
   Maximum speed: 237 km/h at sea level; 201 km/h at 6,000 m; 195 km/h at 7,000 m; 193 km/h at 7,500 m; climb to 5,000 m in 15 minutes 25 seconds; climb to 6,000 m in 21 minutes 24 seconds; ceiling 8,900 m

SPAD 20 Two-Seat Fighter with 300-hp Hispano-Suiza 8Fb
   Span 9.80 m; length 7.34 m; height 2.87 m; wing area 29 sq. m
   Empty weight 867 kg; loaded weight 1,106 kg
   Maximum speed; 242 km/h at sea level; 229 km/h at 2,000 m; climb to 2,000 m in 4.6 minutes; ceiling 8,900 m
   Armament: two synchronized 7.7-mm Vickers machine guns and a single 7.7-mm Lewis gun on a ring mount
   A total of 95 were built