Jean de Chappedelaine at his desk in 1928, holding the 1/10th-scale model of the Gyraptere he built to demonstrate proof of his concept. On the desk to his right is the small box containing the 0-14 h.p. electric motor the inventor used to power the model. The power loading of the model could reach 9lb/h.p. based on static thrust.

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.

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

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.

Of very poor quality, this is the only known photograph of the full-size de Chappedelaine helicopter. Note the venturi tubes fitted to the rotor tips. The very basic framework was fitted with a windshield and two side-by-side seats, although the numerous tethered take-offs and landings were performed by de Chappedelaine alone.

Jean de Chappedelaine continued his aeronautical adventures following the fatal crash of the Aerogyre with a design for a boundary layer control system for helicopter rotors, in which tip-mounted venturi tubes were used to create laminar airflow and equalise the forces acting on the advancing and retreating blades.
BELOW An illustration from patent GB576738 depicting de Chappedelaine’s boundary layer control system for helicopter rotors, which was designed to obviate the need for an articulated link between hub and rotor blades and thus simplify construction and maintenance.

Another illustration from patent GB576738 for de Chappedelaine’s helicopter design, dated January 6, 1944: "The rotors are driven by an engine (14) through shafting (16, 25), and a flywheel (23) may be provided to act as a stabiliser and also as a temporary source of power in the event of engine failure. A variable-speed gearbox or hydraulic coupling (26) may be included in the drive to the tail screws (32, 33), which may be tilted about the axis of shaft (25) by means of a concentric hollow shaft (28) rotatable by a toothed sector (37).