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

Laboratory Eiffel Fighter

  The Laboratory Eiffel fighter is listed as being intended to fulfill the C1 fighter category, but the prototype was actually an experimental aircraft intended to test some of the most advanced aerodynamic features that had been developed by 1918. However, it is interesting to compare the C1 specifications with those actually achieved by the Eiffel fighter. The specification called for a maximum speed of 240 km/h, a payload of 220 to 270 kg, a maximum ceiling of 9.000 m, and a service ceiling of 6,500 m.
  Gustav Eiffel was a pioneer of aerodynamics and it was the staff of his aerodynamics laboratory who designed and developed the Eiffel fighter. The aircraft was a low-wing monoplane and the wing was almost completely of cantilever design except for two bracing struts on either side of the fuselage. The two parallel wing spars were of duralumin. The fuselage was remarkably streamlined, with the engine and single machine gun completely enclosed. The ventral radiator was located beneath the nose. The elevators and rudder were balanced. Estimated maximum speed for the aircraft was 265 km/h at 4,000 m, with an estimated ceiling of 8,000 m and climb to 4,000 m estimated in 10 minutes.
  While the design was strictly the accomplishment of the Laboratory Eiffel staff, led by W. Margoulis, the aircraft was built by the Breguet firm. Hence some sources give its designation as Breguet LE. The initial prototype was fitted with a 180-hp Hispano-Suiza 8Ab engine and the wing structure had been redesigned because of failures in the spars found during static testing. Auxiliary spars were added to carry the ailerons.
  Testing began at Villacoublay in March 9 1918 by Jean Saucliere, a fighter pilot on convalescent leave, who made the first flight but damaged the landing gear on takeoff. Alter the aircraft was repaired, Saucliere was allowed, with some reluctance on the part of Louis Breguet, to attempt the second flight alter Breguet's test pilot, Bailliencourt, expressed reservations about flying the LE. The aircraft rose quickly and flew 50 meters before diving into the ground and bursting into flames; Saucliere was killed. The cause for the crash is unknown, but was unofficially attributed to pilot error.
  Although tragically brief, this second test flight at least established that the aircraft had an impressive performance, and it was estimated that the maximum speed would be 220 km/h at 4,000 in and that the LE could climb to 4.000 in in ten minutes. These were close to the requirements of the C1 specification.
  Based on this estimated performance with only a 180-hp engine, it was planned to re-engine the airframe with a 220-hp Lorraine-Dietrich engine or a 300-hp Hispano-Suiza 8Fb. The airframe for the latter was under construction in January 1918, but apparently the loss of the first prototype resulted in this project being delayed.
At Breguet's insistence, the LE variant with the 220-hp Lorraine-Dietrich was apparently re-designed as a biplane in order to prevent any further structural failures. It was also lightened considerably, possibly also in an attempt to prevent further structural failures.
  It seems that the end of the war, coupled with the intense activity at the Breguet plant (which was producing the Breguet 14 and its derivatives), conspired to keep these developments of the Laboratory Eiffel fighter from being completed. The aircraft did leave one lasting impression on French aviation between the wars; because of the catastrophic failure of the Eiffel prototype, further development of the low-wing monoplane was all but abandoned by the French postwar.


LE Experimental Single-Seat Fighter with 180-hp Hispano-Suiza 8Ab
   Span 9.78 tn; length 6.35 m; height 2.0 m; wing area 20 sq. m
   Empty weight 495 kg, loaded weight 700 kg
   Maximum speed (estimated); 220 km/h at 4,000 m; climb to 4,000 m in 10 minutes; endurance 2 hours
   No armament was fitted to the LE prototype, but two machine guns were planned for production aircraft