The C.6 at Cuatro Vientos in 1924. This autogiro, which used the fuselage of an Avro 504K, was produced by the Spanish Air Force workshops.

Frank T. Courtney in the C.6bis, Farnborough, October 1925.

The C.6bis during one English press demonstrations in October 1925.

A larger-diameter rotor was one of the distinguishing features of the C.6bis. Also visible are the “pegs” beneath the blades on which the starting rope was wound.

The C.12 over Cuatro Vientos in May 1929, piloted by Cierva himself.

The C.12 after a forced landing near Caceres in late July 1929, during Rambaud's return flight from Portugal. Note late type of tailplane.

The C.12 demonstration, Getafe, May 1929.

The C.4 was powered by an 80 h.p. Le Rhone rotary and was based upon the shortened fuselage of a Sommer monoplane.

The C.4 at Getafe aerodrome, Madrid, in 1922. The rotor blades had a hinge which allowed them to “flap.”

The C.5 at Cuatro Vientos aerodrome, Madrid, in 1923. It utilised the fuselage of the earlier C.2, having a 110 h.p. Le Rhone as its powerplant.

Pilot A. Spencer lounges on the fuselage of the short-lived C.5, which ended its life in a crash in July 1923.

In its final form, with a locked rotor head and ailerons on outrigger spars, it made the first successful autogiro flight on January 17, 1923.
A rebuilt machine, shown in Fig. 5, was provided with two small non-lifting ailerons carried on streamlined spars, the windmill axis being rigidly fixed. The machine shown in Fig. 5 made several successful flights, the first being made on January 31, 1923, and being of four minutes duration.

The first official demonstration of an autogiro took place at Getafe aerodrome on January 22, 1923, the C.4 being flown by Lt Alejandro Gomez Spencer.

The Loring-built C.7 at the 1926 Madrid Aeronautical Exhibition.

The C.7 at Loring's airfield near Madrid in June 1927.