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

Caudron G.5

  The Caudron G.4 achieved considerable success as a long-range reconnaissance plane, but its deficiencies had been obvious for some time in 1915. In an attempt to improve the type, Gaston Caudron produced a major redesign of the G.4, designated the G.5.
  The Aviation Militaire had requested development of a three-seat reconnaissance and light bomber aircraft. This A3 specification was for a large machine with gunners fore and aft for clear fields of fire. Planes designed to meet this requirement were Gaston Caudron's G.5 and G.6, Rene Caudron's R series, the Morane-Saulnier Type T, and the Salmson S.M.l.
  While the G.4 had an abbreviated central nacelle, the G.5 featured a conventional fuselage. This enabled it to carry two gunners as required by the A3 specification. Power was supplied by two 80-hp Le Rhone engines. The plane was built of wood and fabric, with steel fittings. It appears that the G.5 retained a wing similar to the G.4; the surface area of both types was nearly identical.
  The aircraft was flown in spring 1915, tested by Gaston Caudron for the SFA. Finding it to be seriously underpowered, he redesigned it into what would be designated the G.6.
  Although the G.5 had significant deficiencies, a few were assigned to operational units. In May 1916 G.5 serial number 678 was assigned to S.A.L. 202. Also in May, C 10 and C 27 received two G.5s each. Their crews were armed with Winchester semi-automatic rifles and a Chauchat machine gun. If these reports are accurate, they suggest that at least a small number of G.5s were built before they were replaced by the G.6.


Caudron G.5 Two-Seat Reconnaissance Light Bomber with Two 80-hp Le Rhone Engines
   Wing area 38 sq. m
   Empty weight 850 kg
   Armament: Winchester semi-automatic rifles and a Chauchat machine gun


Caudron G.6

  The G.4 had initially proved to be successful in the reconnaissance role, but as 1915 progressed the weaknesses of the design became increasingly apparent. The frequently poor weather severely limited the number of sorties and the G.4's layout prevented adequate defense against attacks from the rear. The Aviation Militaire demanded a new category of aircraft to correct these problems; the A3 class of army cooperation aircraft was to perform long range reconnaissance, bombing, and escort fighter duties. They would need two powerful engines to enable them to fly long-range missions or in high winds. A crew of three was specified: a pilot and a front and rear gunner. Gaston Caudron's response to this requirement was to produce the G.5, while Rene designed the R.4 series (initially intended for use as a bomber, but actually used in the A3 role).
  Limited numbers of G.5s were used at the front, but because they were found to be seriously underpowered, Gaston Caudron had it redesigned to feature a wing of increased area and two 110-hp (later 120-hp) Le Rhone engines. The new aircraft followed the general lines of the G.5, retaining a conventional fuselage with machine gun positions fore and aft. The G.6 was designed by Paul Deville. Although by this time Gaston Caudron had died while testing the R.4, the "G" designation was retained by the firm.
  Improved performance was ensured by the two 120-hp Le Rhone engines (although the prototype and early production machines had 110-hp engines). The pilot was seated beneath a cutout in the upper wing. The engines were mounted in nacelles on either side of the fuselage. The landing gear consisted of paired wheels mounted directly beneath each of the nacelles and a rear tail skid. There was a single triangular fin and rudder.
  The prototype G.6 had an abbreviated nose barely protruding ahead of the engines. This did not permit an adequate field of fire, and so the G.6 was redesigned with a longer nose of conical profile. The rear gunner was located well aft of the wings in both the prototype and production G.6s. On some G.6s a wind-driven generator was fitted in the nose gunner's position.
  The upper and lower wings each had two spars made of ash and spruce reinforced with a strip of steel. The rear longerons had two additional steel strips. The ribs were held to the front spar by a mortis and tenon arrangement and to the rear spar by screws. There were 52 ribs in the upper wing and 32 in the lower, spaced every 0.32 m. The 28 struts were of spruce. The tail had one rudder with a fixed forward fin and a single horizontal stabilizer. The fuselage had four main longerons of spruce. The shape of the fuselage was held by piano wire. The floor was made of plywood sheathed in aluminum and placed on the lower longerons. The G.6 had dual controls. The fuel and oil tanks were behind the engines. The engines had aluminum cowlings. A portion of the engine covering was in fabric and was held in place by laces in order to facilitate removal of the fuel and oil tanks. The undercarriage had two N-struts with an oval cross section. Each strut held a pair of wheels. A runner between each pair of wheels, reinforced with springs, which acted as a brake when the aircraft landed. The rear skid was articulated on a bungee cord to reduce the landing shock.
  The aircraft took off and climbed at a speed of 90 to 100 km/h. Cruising speed was around 140 km/h. Descent was at an airspeed of 110 km/h. On approach to landing the speed was to be reduced to 85 km/h and landing was to be at 60 km/h. Pilots were instructed that if the aircraft were to enter a stall they were to avoid violent maneuvers and regain airspeed as quickly as possible. However, pilots found it difficult to recover the G.6 from a stall or spin.

Operational Service

  The prototype G.6 first flew in June 1916 and by the end of 1916 50 Caudron G.6s were at the front. A total of 512 were produced. By 1 August 1917 there were a total of 302 G.6s available to the Aviation Militaire - 133 with the Caudron escadrilles and in the aviation parks, 162 with the R.G.A., and an additional seven in reserve.

  GQG reports indicate there were serious problems with the G.6. It would go into uncontrolled spirals when performing tight turns. The crews were warned to make careful turns and to coordinate use of the rudder and ailerons because use of the rudder alone was believed to result in the aircraft spiraling out of control. These problems became serious enough that the Aviation Militaire ordered the grounding of all G.6s on 8 June 1917. It was found that there was a problem with the tail fin. Once these were replaced the G.6s were allowed to resume flying in mid-June. It was also discovered it was necessary to replace the turnbuckles for the wing rigging. The numerous difficulties with the A3 series of aircraft in general, and the G.6 in particular, led the STAe to create its own A3 plane, which was produced under license by Letord. The Letord series soon replaced the G.6s in service.
  The decision to disperse the A3 series of aircraft to the army cooperation escadrilles also resulted in the G.6 units reequipping with more modern types beginning in 1917. These were of the A2 (tactical reconnaissance and army cooperation) category, including the Breguet 14 A2, Salmson 2 A2, and SPAD 16 A2.


Official STAe Performance Data for the Prototype G.6 with Two 120-hp Le Rhone Engines and a Payload Of 500 kg
   Span 17.21 m; length 8.660 m; height 2.50 m; wing area 36.90 sq. m;
   Empty weight 895 kg
   Maximum speed: 163 km/h at sea level; 151 km/h at 2,000 m; 146 km/h at 3,000 m; 138 km/h at 4,000 m; climb to 500 meters 1 min. 20 sec.; 1,000 m in 3 min. 20sec.; 3,000 m in 14 min. 55 sec.; and 4,000 m in 20 minutes.

Caudron G.6 Two- Or Three-Seat Reconnaissance Plane and Light Bomber with Two 110-hp Le Rhone Engines
   Span 17.22 m; length 8.60 m; wing area 39 sq. m
   Empty weight 940 kg; loaded weight 1,440 kg
   Max speed: 145 km/h at 2,000 m; climb to 2,000 m in 7.5 min.; ceiling 4,400 m; range 275 km; endurance 3 hours.
   Armament: twin 7.7-mm Lewis machine guns fore and aft