The completed Aerogyre at Guyancourt. The first flights of the aircraft were made in September 1934 with the rotary wings locked in conventional aerofoil configuration. It seems likely that the accident that killed Roger Rigaud the following month may have been the result of attempted flight using the rotary wings in autorotation.

Bearing the legend “Aerogyre de Chappedelaine, Type CD1” and “Avions Caudron” in smaller letters beneath it on the rudder, the prototype (and sole) Aerogyre, based on a C.270 Luciole biplane, has its final touches added at the very busy Caudron factory at Issy-les-Moulineaux in the south-western suburbs of Paris.

Two images of the Aerogyre scale model tested in the Eiffel windtunnel and others in Paris. Note the discs attached to the rotary wings to stop spanwise lift migration, and the fixed upper wing fitted with ailerons, which was to have been deleted on production aircraft.

Another Aerogyre windtunnel model, this time with a pair of fixed narrow-chord tandem wings mounted above the rotary wings, an idea not adopted for the prototype.

In June 1931 Jean de Chappedelaine filed French patent FR523527A for a “portable glider using rotary wings”, the drawings for which are seen here. Note the low-curvature S-shaped aerofoil profile of the rotary wings in Fig 3.

A contemporary illustration of the portable gliding harness used for extending jumps while skiing, as published in Jacques Thyraud’s 1977 book Histoire Des Hommes Volants. Where the illustration of this unlikely apparatus appeared originally remains unknown.

Figs 1 and 2 from patent FR723542A, concept illustrations of what would evolve into the Aerogyre.