Cierva C. 25
| Cierva C. 25 | |
|---|---|
| Type: | Gyroplane |
| Design country: | |
| Manufacturer: | |
| First flight: |
April 21, 1932 |
| Number of pieces: |
1 |
The Cierva C.25 (also Comper C.25 ) was an autogyro , the early 1930s in one copy in the UK in the Comper Aircraft Company designed and built. Only the rotor system came from the Cierva Autogiro Company . Since Comper used the Swift airframe as the basis, the C.25 is also referred to as the Swift variant.
history
The development of the C.25 was an attempt by Comper Aircraft to build a cheap gyroplane for sports purposes. It is not clear whether Comper approached Cierva about the construction of the C.25, or whether the request came from Cierva. Development began in March 1931, the peak of Swift production. Comper was able to deliver one Swift per month. The work continued throughout 1931, the machine was not ready for the first test flights until February 1932. However , the C.25 never carried the G-ABTO license plate assigned on January 25, 1932 .
Juan de la Cierva himself carried out a first attempt at flight in March 1932, but the machine took off too early, fell back to earth and suffered severe damage. Cierva attributed this to the inadequate quality of the balsa wood rotor blades. After replacing the balsa leaves with the usual fabric-covered leaves with a ribbed structure, Cierva was able to carry out the successful maiden flight on April 21, 1932. Like the C.24 in its original form, the C.25 also suffered from insufficient directional stability. A large vertical tail fin was temporarily installed, but this brought only a minor improvement. The problem was probably due to the large rotor pylon, which was responsible for the vertical tail unit being completely in the shadow of the flow . One solution was the addition of two vertical disks, which were arranged roughly in the middle of the elevator.
Comper did not plan to produce the C.25 in series, but would have built more copies if orders had been received. In March 1933 the company moved from Hooton Park near Liverpool to Heston , the "Mecca" of British light aircraft construction in the 1930s. The C.25 was also transferred there by Nicholas Comper and presented to the public in nearby Hanworth on April 27 , although flight demonstrations were dispensed with.
When a rotor blade broke a year later during a flight demonstration in Heston, the C.25 was dismantled and probably later scrapped when Comper was merged into the newly founded company Heston Aircraft the following year .
construction
The basic concept corresponded to the design initially chosen for the Cierva C.19. This means that there was still no tilting rotor head ( Direct Control ), as was later tested on the Cierva C.19 Mk. V and used in series on the Cierva C.30 . Comper used the rotor system supplied by Cierva with a cantilever three-blade rotor. The flight controls were conventional with elevators, rudders and ailerons. In contrast to the C.19 and C.24, the ends of the extended wing were not bent upwards. Before the start, the rotor could be set in rotation by the motor via a mechanical coupling.
Like the Swift, the C.25 was a pure wood construction, with the exception of the rear fuselage ceiling, the fuselage being planked with plywood. Both the wooden structure of the high rotor pylon and the front fuselage immediately behind the engine had a metal cladding. The wings, the upper fuselage ceiling and the tail surfaces were covered with fabric.
The 85 hp Pobjoy Cataract star engine had a reduction gear and drove a two-bladed propeller with a diameter of 1.98 m. It was probably actually a Pobjoy-R engine, as the engine was only renamed Cataract later (1934?) . The landing gear was longer and had a larger track width than that of the Swift. Comper supplied a precisely fitted suitcase for the front of the two small luggage compartments.
See also
literature
- Arthur WJG Ord-Hume: Autogiro - Rotary Wings Before the Helicopter , Mushroom Model Pub., 2009, ISBN 978-83-89450-83-8 , pp. 208-210, pp. 235 f.
- Richard Riding: Cierva C. 25 - British pre-war lightplanes No 6 . In: Airplane Monthly June 1989, pp. 374-376
Web links
- Photos and three-sided plan from Airplane Monthly June 1989 (accessed April 28, 2018)
Individual evidence
- ^ Bill Gunston: World Encyclopedia of Aero Engines , 3rd updated edition, 1995, p. 116