Cierva C.8

The Cierva C.8 was an experimental autogyro built by Juan de la Cierva in England in 1926 in association with Avro. Like Cierva's earlier autogyros, the C.8s were based on existing fixed-wing aircraft fuselages - in this case, Avro 552s.
The first example, the C.8R (known to Avro as the Type 587) was a rebuild of the C.6D, fitted with stub wings and paddle-shaped main rotor blades. This was followed by the new-built C.8V (or Type 586) that was eventually converted back into an Avro 552 after testing. The next model was the definitive C.8L prototype (or Type 575).
By now, Cierva's efforts were attracting the attention of buyers. The first customer was the British Air Ministry, which placed an order for a machine in 1927. This was completed as the Type 611, test flown by Bert Hinkler at Hamble and then delivered to the Royal Aircraft Establishment by Cierva himself in Britain's first cross-country rotorcraft flight on 30 September that year. The next example was purchased by Air Commodore James G. Weir, chairman of Cierva, and flown in the 1928 King's Cup Air Race before being used to make demonstration flights around continental Europe.
The two final C.8s were sold in 1928, one to the Italian government, and one to American Harold Pitcairn, who would go on to purchase manufacturing rights for the United States. The C.8W bought by Pitcairn would make the first autogyro flight in the United States at Willow Grove, Pennsylvania in January 1929.
As of 2007, two examples are extant: Weir's machine preserved at the Musée de l'Air et de l'Espace in Paris, and Pitcairn's at the National Air and Space Museum in Washington DC.
Technical data for C.8L Mk.II

Engine: 1 x Armstrong Siddeley Lynx IVC 2-cylinder pistone engine, rated at 150kW, main rotor diameter: 12.09m, fuselage length: 8.69m, height: 4.50m, take-off weight: 1120kg, max speed: 161km/h, service ceiling: 1200m, range: 410km