Delabrosse et Christollet

  Tested in September 1910, this big and unsuccessful tractor was probably the first with variable-geometry wing. Each wing panel was a large semicircle of fabric stretched between the fuselage and curved leading edge spars which pivoted on vertical struts to vary the wing area: the span could thus be modified from 11 to 7 m. The long partly-covered triangular-section fuselage had triangular control surfaces at the rear.
  Contemporary records show that Christollet was planning a machine called Abeille (bee), in 1909; this may have been the Delabrosse et Christollet - if, indeed, it was built.