Lefebvre

   At the end of 1909 L'Aero published a brief notice in which a Lefebvre, "34 years old, 60 kg, at the end of his resources because of aviation experiments," was looking for a pilot's job. This was doubtless Louis Lefebvre, who had by then left Fernandez for whom he had worked as a mechanic. Subsequently he became known for founding at Rouen a company to build his own design, La Mouette (gull); but his career was actually more important than this suggests.
   In March 1910 Lefebvre was working on a large monoplane of 17-meter span, reportedly to have featured bat-shaped wings, which he may have begun much earlier. Also in 1910 he and his brother Philippe, an accountant, organized a company in Rouen to build La Mouette; the firm was shortly afterwards disbanded and re-formed in 1911 with a new title, La Societe Nouvelle pour la Construction de l'Aeroplane La Mouette. The aeroplane was described as a "double monoplane" with telescoping wing panels: the span could vary from 6 to 10 m. The machine was shown at the Brussels exhibition in 1910.

   (Span: 6 to 10 m; length: 8.5 m; gross weight: 400 kg; 35-40 hp motor)
  
   But in April 1911, La Mouette was described in L'Aero as a stagger-wing biplane. It had a covered rectangular-section box fuselage, and triangular vertical fins and tailplanes. The lower pair of trapezoidal wings were fixed to the top of the fuselage, and the top pair, of the same size and shape, were higher and forward, with more dihedral. Between the 2 main spars of the top wings ailerons could slide in and out at the tips, operating independently and actuated by cables, sheaves, and cogwheels, controlled by 2 levers to the right of the pilot.

   (Span: 8 to 12 m; wing area: 28 to 33 sqm; length: 9.6 m; gross weight: 520 kg; 50 hp Clerget)
  
   The same year, 1911, at Chartres, Sadi-Lecointe was testing another Lefebvre, this one a monoplane, a big 3-seater, for the Concours Militaire. The rectangular fuselage was completely covered, and the tail surfaces were large. It is likely there was no elevator, the control being accomplished by varying the wing incidence: the wings were of very high aspect ratio, rectangular in shape, built around 4 spars. The ailerons were trapezoidal surfaces hinged along the wingtips.

   (Span: 17 m; length: 12 m; wing area: 55 sqm; 50 hp V8 ENV)
  
   There was also a La Mouette V mentioned in 1912, powered by an 80 hp Anzani.