Cierva C.10
| Cierva C.10 | |
|---|---|
| Type: | Gyroplane |
| Design country: | |
| Manufacturer: |
Cierva Autogiro (construction), |
| First flight: |
1928 (only roll tests) |
| Number of pieces: |
1 |
The Cierva C.10 was a gyroplane designed by Juan de la Cierva and built in the late 1920s by the Bristol-based company George Parnall & Co. as a licensee. That is why the name Parnall-Cierva C.10 is also used.
history
The construction of the C.10 was commissioned in accordance with the requirements of Air Ministry Specification 4/26 with contract 642578/25 . It also received an RAF serial number (J9038). Parnall built the machine at his facility on the Yate airfield in Gloucestershire , where the C.10 was completed in the early months of 1928. Unlike Avro, Parnall did not use an existing aircraft as the basis for its license construction, but built it from scratch.
On April 26, 1928, the first taxi attempts were made on the Yate airfield. Avros test pilot HA Hamersley turned the machine into the wind of force 4 to 5 and rolled about 200 m when the machine suddenly lay on its left side. The following investigation showed the practically vertical arrangement of the rotor mast together with the only slightly effective rudder as the cause of the accident. Accordingly, when the J9038 was rebuilt, the rotor mast was inclined 5 degrees to the right, the track width was increased to 3.05 m and the Chassis struts attached to the booms instead of the longitudinal straps. The next flight attempt took place on November 5, 1928 on the Andover airfield, with the C.10 being piloted by the Cierva test pilot AH Rawson. However, when he raised the stern while attempting to take off, the machine rolled to the right and lay on its back. More than 20 years after the accident, the designer Harold Bolas stated that, in his opinion, both accidents can be traced back to ground resonance effects . The C.10 was not rebuilt.
construction
The single-seater was powered by an uncovered five-cylinder Armstrong Siddeley Genet radial engine , which had an output of 80 hp and acted on a two-blade propeller. The 6.91 m long hull made of wood had a simple framework structure covered with fabric. Only the front part of the fuselage consisted of a steel framework. The rudder unit consisted of a wire-braced small fin and a relatively large, unbalanced rudder. The entire tail unit was a steel structure and covered with fabric. Cased tubular steel spars, which were attached to the lower longitudinal members of the fuselage and braced against the fuselage, carried large ailerons. The span of the spars was about 5.20 m. The simple grinding spur chassis had a track width of 2.14 m and had oil struts.
The four-blade rotor with great depth was of the “paddle type” and sat on a pylon composed of six lined tubes. The downward movement of the blades was limited by telescopic damper units, while the upward flapping movement in the horizontal joints was not restricted. The clockwise rotating rotor had to be set in rotation manually and was only given the speed required for lifting when the machine was rolling. The rotor did not have any vertical joints , which Cierva introduced after a blade root broke and the C.6C subsequently crashed in early 1927. As a result, the tensioning cables between the rotor blades, which were used to limit the deflection of the swivel joints, were also missing on the C.10. It can no longer be determined today what part the design departments of Cierva and Parnall played in this design. Probably, however, Parnall's Harold Bolas only designed the hull, while Cierva was responsible for the rotor mechanism.
See also
literature
- Philip Jarrett: Parnall's pinwheels . In: Airplane Monthly August 1988, pp. 474-478
- Arthur WJG Ord-Hume: Autogiro - Rotary Wings Before the Helicopter , Mushroom Model Pub., 2009, ISBN 978-83-89450-83-8 , p. 75 f., P. 289
Individual evidence
- ↑ Parnall-Cierva C.10 (accessed October 21, 2017)