Cierva C.8
| Cierva C.8 | |
|---|---|
|
|
| Type: | Gyroplane |
| Design country: | |
| Manufacturer: |
Cierva Autogiro (construction), |
| First flight: |
1926 |
| Number of pieces: |
6th |
Cierva C.8 refers to a series of gyroscopes by the designer Juan de la Cierva , six of which were manufactured by Avro in Great Britain in the mid-1920s .
Avro names
The system according to which Avro assigned its design numbers for the Cierva samples is difficult to understand from today's perspective. Sometimes new numbers were assigned with only minor changes to existing aircraft, with many gyroplane cells often being changed and rebuilt. The same cell could have two or three different design numbers.
history
C.8R (Avro 587)
The Cierva C.6D , flown in Hamble for the first time on July 29, 1926, was the first two-seat gyroplane. On September 5, 1926, Ernst Udet also flew the plane transported overland to Tempelhof. After returning, it was rebuilt as the Cierva C.8R and received a three-blade rotor with greater depth and vertical joints with which the risk of a fatigue break at the blade root should be eliminated. These new hinges allowed the rotor blade to have limited movement fore and aft as it rotated. The C.8R also received additional stub wings. Controls were only available at the back. This work was completed on October 15, 1926. Avro's chief test pilot Bert Hinkler flew the C.8R with a two-bladed rotor in September 1927. Due to strong vibrations, however, the two-blade rotor was no longer used.
C.8V (Avro 586)
Another type of the C.8 series was created in 1926 from the Avro 552A ( aircraft registration G-EAPR), which had previously served various test purposes and was used for gyroplane research. The wings were removed and a rotor and control system installed like the C.8R. The aircraft then received the new designation Cierva C.8V (Avro 586). The main differences to the C.8R were an additional dorsal fin and the ability to fly the machine solo from the front seat. Finally, a rotor of shallower depth was also tested, which significantly improved performance.
Later the C.8V was experimentally equipped with a simple three-legged landing gear and in January 1927 with a four-wheel landing gear. In August 1927, however, Avro upgraded to the standard tail landing gear and in the following month it received the civilian license plate G-EBTX. In 1930 it was rebuilt to the state of the Avro 552A and received the G-ABGO registration.
C.8L (Avro 575, 611 and 617)
The promising results of the testing of the C.6C, C.6D / C.8R and C.8V prompted the Air Ministry to order another prototype, which was to be based on the fuselage of an Avro 504N with a Lynx engine . The rotor had four "paddle-type" blades; H. the blade depth was very shallow at the hub, then increased sharply outwards and remained almost constant up to the blade tip. Each blade had a tubular steel spar with wooden ribs, the mean blade depth being 91.5 cm. With the prototype and the three other machines, the rotor could be brought to a sufficient speed before take-off either by a rope wound around the hub or by rolling it quickly. The Cierva C.8L Mk.I (Avro 575) had the standard fuselage and propulsion of an Avro 504N with a pylon composed of four tubes above the front cockpit. The chassis was revised and got a wider track as well as oil-rubber struts with a longer travel to work. Instead of being attached to the lower fuselage longeron, as is customary on the Avro 504, the landing gear struts were attached to the upper longeron.
Bert Hinkler carried out the first flight at Avro in Hamble in 1927, with the RAF Roundels aircraft and the service serial no. J8930 wore. Cierva himself flew the C.8L Mk.I from Hamble to Farnborough on September 30, 1927, making the first overland flight of a rotary wing aircraft in Great Britain. The flight tests began there with a rotor design with a blade depth of only 53.4 cm, as was also used on the C.8V. Since this rotor did not prove itself, it was reverted to the original design on January 11, 1928. The machine stayed in Farnborough until April 1930 and was lost two months later in Andover, Hampshire.
The civilian counterpart to the C.8L Mk.I was the C.8L Mk.II (Avro 611, registration G-EBYY), which was built in 1928 for JG Weir, the chairman of the Cierva Company. This variant was very similar to the Mk.I, but received relatively thick wings with a small span on which the ailerons were attached. The landing gear struts were attached to the front spar of the wing. The engine, a Lynx IV , was more heavily clad than that of the Mk.I. The first flight with Hinkler at the wheel took place in early May 1928. With the newly appointed test pilot AH Rawson, the Mk.II started at the King's Cup in Hendon on July 20, 1928, but had to give up the race shortly afterwards due to an emergency landing due to a lack of fuel. On September 18, 1928, Cierva flew with a French journalist in the G-EBBY from Croydon to Le Bourget, crossing the English Channel. The Mk.II was the first rotary wing aircraft to do this. After the demonstrations there, Cierva and Rawson flew to Berlin via Brussels on October 3, 1928. Rawson then returned to Paris on October 13, completing the 2300 km scenic flight there. The C.8L Mk.II never returned to England and is now exhibited in the Musée de l'air et de l'espace in Paris.
It was thanks to the public attention gained with the flights of the C.8L Mk.II that Avro received two orders from abroad. The first resulted in the C.8L Mk.III (Avro 617) with a Lynx IV engine, which was built for the Italian government. Rawson conducted the test flights in September 1928. The second order came from Harold Pitcairn, a US aircraft manufacturer who had visited the Avro factory in early 1928. The C.8L Mk.IV (also C.8W ) built for him flew for the first time in November 1928 and was powered by a 225 hp Wright J-5 Whirlwind engine. Pitcairn also acquired the manufacturing rights for the USA and founded Pitcairn-Cierva Autogiro Co. Inc. , based in Bryn Athyn, Pennsylvania. The C.8L Mk.IV was shipped to the USA in December 1928 and made its maiden flight there in January 1929 at Pitcairn Field in Willow Grove , which was also the first flight of a gyroplane in the USA. In 1931 Pitcairn donated the machine to the Smithsonian Institution .
See also
literature
- Planes from A – Z - Cierva Autogyros . In: AERO - The illustrated compilation of aviation. No. 51, pp. 1424 ff., 1984, Marshall Cavendish.
- TR Hiett: Cierva's rotating wings . In: AIR Enthusiast July / August 2003, pp. 26–31
- AJ Jackson: Avro Aircraft since 1908 , Putnam, 1965, 2nd edition 1990, ISBN 0-85177-834-8 , pp. 233-240
Web links
Individual evidence
- ↑ Hiett, 2003, p. 29
- ↑ C.8L Mk.IV in flight
- ↑ photo of C.8L Mk.IV after the handover to the Smithsonian Institution