Avro Rota
| Industry | Aviation |
|---|---|
| Founded | 1920s |
| Founder | Juan de la Cierva |
| Headquarters | United Kingdom |
| Products | Autogyros (Cierva C.30) |
Template:More footnotes
Template:Infobox aircraft
The Cierva C.30 represents an autogyro conceptualized by Juan de la Cierva and manufactured under license by the Cierva Autogiro Company. Production was undertaken by A V Roe & Co Ltd (Avro) as the Avro 671, by Lioré-et-Olivier under the designation LeO C.301, and also by Focke-Wulf.
Design and development
Prior to the experimental Cierva C.19 Mk V, autogyros were maneuvered similarly to fixed-wing airplanes, utilizing control surfaces such as ailerons, elevators, and rudders to deflect airflow. However, these conventional controls lost effectiveness at the low speeds typical of autogyro operations, especially during landing phases. The experimental model demonstrated that a tilting rotor hub equipped with a suspended control stick—extending directly to the pilot's cockpit—enabled adjustment of the rotor plane. This innovation, termed direct control, was incorporated into the C.30. The production variant, known as the C.30A in Britain, was preceded by multiple developmental prototypes.
The initial production model, designated C.30, featured a radial engine powering a three-blade rotor with a diameter of 37 ft (11.3 m), mounted on a rear-leaning tripod structure. The control column extended into the back of the dual cockpits for pilot operation. It was equipped with the five-cylinder, 105 hp (78 kW) Armstrong Siddeley Genet Major I engine previously used in the C.19 series. The airframe had a fabric-covered fuselage supporting an unbraced tailplane lacking elevators but fitted with upturned tips. To counteract roll-axis torque generated by the propeller, the port side of the tailplane incorporated an inverted aerofoil section. Due to the rotor’s sagging position while stationary—a common characteristic of autogyros—a tall vertical tail was impractical; instead, a long and low dorsal fin extended well beyond the tailplane functioning as a fixed rudder and was complemented by a ventral fin below. The wide-track landing gear consisted of two single wire-braced legs on each side and included a small tailwheel. This design first took flight in April 1933. Subsequently, four enhanced prototypes labeled C.30P (with "P" indicating pre-production) were developed featuring a four-legged pyramid rotor mount and strengthened undercarriage supported by three struts per side. Additionally, their rotors could be folded backward for easier transportation. These versions were powered by a more robust seven-cylinder Armstrong Siddeley Genet Major IA radial engine delivering 140 hp (104 kW).
The finalized production variant, called the C.30A by Avro, was produced under license across Britain, France, and Germany and closely resembled the preceding C.30P model. A significant modification included an expanded undercarriage track with revised strut arrangements; notably, the uppermost leg featured a distinct knee joint reinforced with wire bracing. Additional strengthening was applied to both tailplane and fin structures, each equipped with small movable trim surfaces for improved control. Each licensee incorporated domestically manufactured engines and assigned slightly different designations accordingly. In total, 143 units of the production C.30 were constructed, establishing it as the most widely produced autogyro prior to World War II.
Between 1933 and 1936, de la Cierva utilized one particular C.30A (registration G-ACWF) to trial his final advancement in autogyro technology before his fatal accident in December 1936 during takeoff from Croydon Airfield in England aboard a KLM Douglas DC-2 airliner. This innovation involved an "autodynamic" rotor head enabling engine-driven rotor spin-up to speeds exceeding normal takeoff RPMs at zero rotor blade pitch angle; subsequently, blade pitch could be rapidly increased to generate an upward jump of approximately 20 ft (6 m), allowing takeoff without prior forward motion.
At least one example of the Royal Air Force’s (RAF) C.30A was equipped with floats for water operations as a Sea Rota as early as January 1935.
Production
- Avro
In 1934, Avro secured the production licence and subsequently manufactured 78 units under their own designation. These were equipped with the Armstrong Siddeley Genet Major IA engine, a 7-cylinder radial powerplant delivering 140 hp (100 kW), which the RAF referred to as the Civet 1. The inaugural C.30A model was completed and handed over in July 1934.
- Lioré-et-Olivier
In France, Lioré-et-Olivier produced twenty-five aircraft designated as the LeO C.301, powered by a 175 hp (130 kW) Salmson 9NE, a 9-cylinder air-cooled radial engine.
- Focke-Wulf
Germany saw the construction of forty units by Focke-Wulf, named the Fw 30 Heuschrecke (meaning Grasshopper), each fitted with a Siemens Sh 14A seven-cylinder radial engine producing 140 hp (105 kW).[1][2]
Operational history
_(14714156820).jpg)
Out of the 66 Avro-built aircraft not operated by the RAF within the UK, at least 37 were registered domestically for some duration.[3] While approximately a dozen were exported internationally, many others were utilized by affluent private owners and flying clubs that provided autogyro flight training. By the late 1930s, private pilots increasingly preferred fixed-wing aircraft for their greater comfort and efficiency, prompting more C.30s to be sold overseas. Consequently, the Autogyro Flying Club at London Air Park, Hanworth remained the primary operator in Britain. Avro directly exported 26 units to both private individuals and foreign military organizations interested in exploring autogyro capabilities.
In 1934, a Spanish Navy C.30 flown by Cierva successfully landed on the seaplane tender Dedalo, anchored in Valencia harbour, and subsequently took off from it.[4]
In September 1935, five pilots from the Lithuanian Aero Club undertook an "air train" journey in C.30As alongside a Schneider Grunau Baby glider and a de Havilland DH.60 Moth aircraft, traveling through Baltic states including Kaunas, Riga, Tallinn, and Helsinki.[5]
Twelve Avro-produced C.30As served with the Royal Air Force as Avro 671 Rota Mk 1 models (serial numbers K4230 to K4239, plus K4296 and K4775). Delivered between 1934 and 1935, these aircraft were assigned to the School of Army Co-operation at RAF Old Sarum near Salisbury.
Between 1939 and 1940, numerous civilian-owned C.30s were requisitioned into RAF service. By 1940, they operated with 1448 Flight at RAF Duxford, later transitioning to 529 Squadron at RAF Halton, where they contributed to radar calibration tasks. Following disbandment in October 1945, twelve surviving aircraft were returned to civilian ownership.
Though most did not remain operational for long thereafter, two examples were employed by Fairey Aviation Company for pilot training on rotary-wing techniques during their Fairey Gyrodyne helicopter project. The organisation Rota Towels maintained one ex-RAF Rota airworthy under registration G-AHTZ until it was lost in an accident in 1958. Another notable aircraft is G-ACUU, preserved by the Imperial War Museum at Duxford; it had an extended service life starting with Air Service Training Ltd in 1934 before military impressment as Rota HM580 in 1942 for use with 529 Squadron. Post-war it returned to civilian hands under G.S. Baker based at Birmingham's Elmdon Airport, retaining its original registration along with the nickname Billy Boy, remaining active until its retirement in 1960.
Following extensive restoration efforts at Maestranza Aérea de Albacete, a C.30 was successfully flown again on 15 January 1998 by Lieutenant Colonel Fernando Iglesia. After sustaining a severe accident in June 2000 that nearly resulted in loss of an arm for the pilot, this aircraft was donated to the Museum of Aeronautics and Astronautics, located at Madrid's Cuatro Vientos air base.[6][7]
Variants
- C.30
- Equipped with a 105 hp (78 kW) Armstrong Siddeley Genet Major I radial piston engine.
- C.30P
- Enhanced version powered by a 140 hp (104 kW) Armstrong Siddeley Genet Major IA radial piston engine.
- C.30A
- The principal production variant, featuring a 140 hp (104 kW) Armstrong Siddeley Genet Major IA radial piston engine.
- Rota Mk I
- The RAF's designation for the Cierva C.30A model.
- Lioré et Olivier LeO C-30
- A total of 59 Cierva C.30s manufactured under license, fitted with 175 hp (130 kW) Salmson 9Ne engines, supplied to both the French Air Force and French Navy. All LeO C-30 autogyros were either destroyed or seized by German forces during the 1940 invasion of France.
- Lioré et Olivier LeO C-30S
- Only one unit, construction number 26, was completed as the exclusive C-30S variant.
- Lioré-et-Olivier LeO C-301
- An upgraded model featuring improved Messier oleo-pneumatic shock absorbers, flotation equipment for safer sea ditching, and a tripod main rotor support. By early June 1940, six aircraft had been delivered to the French Navy.
- Lioré et Olivier LeO C-302
- Early autogyros experienced relatively lengthy take-off distances. To address this, two C-301 units were modified with Cierva's "Jump" head mechanism, enabling vertical lift-off after a brief ground roll. These C-302s were primarily used for rotor and landing gear component testing before development ceased around 1949–1950.
- Focke-Wulf C 30 Heuschrecke
- (Heuschrecke meaning Grasshopper) Forty units produced, each powered by a 140 hp (104 kW) Siemens Sh 14A seven-cylinder radial engine.
Aircraft on display
- Argentina
- Cierva C.30A LV-FBL is exhibited at the Museo Nacional de Aeronáutica de Argentina.
- Australia
- Cierva C.30A VH-USR is showcased at the Powerhouse Museum, Sydney.
- France
- LeO C-302 F-BDAD is on display at the Musée de l'Air et de l'Espace, Paris.
- Italy
- Cierva C.30 I-CIER is presented at the Museo della Scienza e della Tecnologia "Leonardo da Vinci", Milan.
- Netherlands
- Cierva C.30A SE-AFI can be found at the Aviodrome.
- Spain
- Flyable reproduction of Cierva C.30A XVU.1-1, powered by a Siemens engine, is displayed at the Museo del Aire, Madrid.
- United Kingdom
- Avro Rota I K4232 exhibited at the Royal Air Force Museum, London.
- Cierva C.30A AP506 (damaged wreck) displayed at the Helicopter Museum, Weston-super-Mare.
- Cierva C.30A AP507 on view at the Science Museum, London.
- Avro Rota I HM580, formerly registered as G-ACUU, is part of the collection at the Imperial War Museum Duxford.
- United States
- Cierva C.30A K4235 is displayed at Fantasy of Flight, Polk City, Florida.
Military users
Civilian operators
- Aero Club of Lithuania - operated a single Avro-produced C.30A, obtained in 1934[9]
Technical specifications (C.30A)
Notes
- ↑ Orbis 1982–1985, p. ?.
- ↑ Smith 1973, p. 94.
- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs namedAJJCiv - ↑ La Cierva and the Transportable Station of Naval Aeronautic (in Spanish) Archived 2008-06-15 at the Wayback Machine
- ↑ Lithuanian Aviation History 1919-1940. Air train (in Lithuanian)
- ↑ The Spanish Air Force promotes the construction of a replica of the La Cierva C30 autogyro (in Spanish)
- ↑ La Cierva C.30 autogyro flies again (in Spanish)
- ↑ Danish Air Museum
- ↑ "Cierva Avro C-30A" (in Lithuanian). Retrieved 24 April 2023.
{{cite web}}: CS1 maint: unrecognized language (link)
Bibliography
- Barratt, M. "Talkback". Air Enthusiast No. 107, September/October 2003. p. 75. Template:ISSN
- Cortet, Pierre (June 2001). "Rétros du Mois" [Retros of the Month]. Avions: Toute l'Aéronautique et son histoire (in français) (99): 6. ISSN 1243-8650.
- Elliott, Bryn (January–February 1999). "On the Beat: The First 60 Years of Britain's Air Police". Air Enthusiast (79): 68–75. ISSN 0143-5450.
- Jackson, A.J. (1973). British Civil Aircraft 1919-72: Volume II. London: Putnam and Company. ISBN 0-85177-813-5.
- Munson, Kenneth (1973). Helicopters and other Rotorcraft since 1907 (Blandford Colour Series). London: Associate R.Ae.S. ISBN 0-7137-0610-4.
- Pacco, John (2003). "Cierva C-30A". Belgisch Leger/Armee Belge: Het militair Vliegwezen/l'Aeronautique militaire 1930-1940. Artselaar, Belgium. p. 92. ISBN 90-801136-6-2.
{{cite book}}: CS1 maint: location missing publisher (link) - Smith, J. Richard (1973). "C 30 Heuschrecke". Focke-Wulf, an Aircraft Album. London: Ian Allan. ISBN 0-7110-0425-0.
- Thetford, Owen (1957). Aircraft of the Royal Air Force 1919-57. London: Putnam and Company.
- The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). Orbis Publishing.
- Moulin, Jacques (2003). Les autogires LeO C.30 & C.301. France: Editions Leila Presse. ISBN 9782914017152.