Louis Béchereau, pioneer constructor, devised patented form of lightweight monocoque construction, collaborated with Kellner (motor bodybuilders) and produced fuselages for Blériot-SPAD 510 fighter. Same partnership built 3 experimental aircraft with patented wing with forward fixed portion and abnormally large rear portion pivoted far below wing to serve as ailerons and as slotted flaps: E.1, E.C.4 and E.D.5, all 1936-7.