This prototype was completed early in 1921. Above the centre of gravity of a Hanriot fuselage retaining its customary elevators and rudder was fitted a three-bladed rotor, the blades of which incor-porated variation of the angle of incidence.

Of this aircraft, La Cierva himself spoke as follows: "My first experiments with this type were encouraging. But after this model had been damaged and reconstructed nine times, it seemed clear that the solution would not be found in such a design." Gyroscopic effects in fact proved virtually unsurmountable.

P.Lambermont "Helicopters and Autogyros of the World", 1958