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The autogyro was invented by Spanish engineer Juan de la Cierva in an attempt to create an aircraft that could fly safely at low speeds. He first flew one on 9 January 1923, at Cuatro Vientos Airfield in Madrid. The aircraft resembled the fixed-wing aircraft of the day, with a front-mounted engine and propeller. Cierva's autogyro is considered the predecessor of the modern helicopter.

The success of the autogyro garnered the interest of industrialists and under license from Cierva in the 1920s


A modern, closed-cabin, pusher-propeller autogyro in flight

A modern, closed-cabin, pusher-propeller autogyro in flight

Juan de la Cierva was a Spanish engineer and aeronautical enthusiast. In 1921, he participated in a design competition to develop a bomber for the Spanish military. De la Cierva designed a three-engined aircraft, but during an early test flight, the bomber stalled and crashed. De la

Cierva was troubled by the stall phenomenon and vowed to develop an aircraft that could fly safely at low airspeeds. The result was the first successful rotorcraft, which he named Autogiro in 1923. De la Cierva's autogyro used an airplane fuselage with a forward-mounted propeller and engine, an un-powered rotor mounted on a mast, and a horizontal and vertical stabilizer. His aircraft became the predecessor of the modern helicopter.

Early development[]

After four years of experimentation, Juan de la Cierva invented the first practical rotorcraft the autogyro (autogiro in Spanish), in 1923. His first three designs (C.1, C.2, and C.3) were unstable because of aerodynamic and structural deficiencies in their rotors. His fourth design, the C.4, made the first documented

flight of an autogyro on 17 January 1923, piloted by Alejandro Gomez Spencer at Cuatro Vientos airfield in Madrid, Spain (9 January according to Cierva).

De la Cierva had fitted the rotor of the C.4 with flapping hinges to attach each rotor blade to the hub. The flapping hinges allowed each rotor blade to flap, or move up and down, to compensate for dissymmetry of lift, the difference in lift produced between the right and left sides of the rotor as the autogyro moves forward. Three days later, the engine failed shortly after takeoff and the aircraft descended slowly and steeply to a safe landing, validating De la Cierva's efforts to produce an aircraft that could be flown safely at low airspeeds.

Winter War[]

During the Winter War in 1939-1940, the USSR's air force used armed Kamov A-7 autogyros to provide fire correction for artillery batteries carrying out 20 combat flights.

World War II[]

The Avro Rota autogyro, a military version of the Cierva C.30 was used by the Royal Air Force to calibrate coastal radar stations during and after the Battle of Britain.

Postwar developments[]

The autogyro was resurrected after World War II when Dr. Igor Bensen, a Russian immigrant in the US, saw a captured German U-Boat's Fa 330 gyro glider and was fascinated by its characteristics. At work, he was tasked with the analysis of the British military "Rotachute" gyro glider designed by expatriate Austrian Raoul Hafner. This led him to adapt the design for his purposes and eventually market the Bensen B-7 in 1955. Bensen submitted an improved version, the Bensen B-8M, for testing to the United States Air Force, which designated it the X-25. The B-8M was designed to use surplus McCulloch engines used on flying unmanned target drones.

Ken Wallis developed a miniature autogyro craft, the Wallis autogyro, in England in the 1960s, and autogyros built similar to Wallis' design appeared for several years. Ken Wallis' designs have been used in various scenarios, including military training, police reconnaissance, and in a search for the Loch Ness Monster, as well as an appearance in the 1967 James Bond movie You Only Live Twice.

Three different autogyro designs have been certified by the Federal Aviation Administration for commercial production: the Umbaugh U-18/Air & Space 18A of 1965, the Avian 2/180 Gyroplane of 1967, and the McCulloch J-2 of 1972. All have been commercial failures, for various reasons.

Russian Gyroplanes Gyros-2 Smartflier.

Russian Gyroplanes Gyros-2 Smartflier

Bensen Gyrocopter[]

The basic Bensen Gyrocopter design is a simple frame of square aluminum or galvanized steel tubing, reinforced with triangles of lighter tubing. It is arranged so that the stress falls on the tubes, or special fittings, not the bolts. A front-to-back keel mounts a steerable nosewheel, seat, engine, and a vertical stabilizer. Outlying mainwheels are mounted on an axle. Some versions may mount seaplane-style floats for water operations.

Bensen-type autogyros use a pusher configuration for simplicity and to increase visibility for the pilot. Power can be supplied by a variety of engines. McCulloch drone engines, Rotax marine engines, Subaru automobile engines, and other designs have been used in Bensen-type designs.

The rotor is mounted atop the vertical mast. The rotor system of all Bensen-type autogyros is of a two-blade teetering design. There are some disadvantages associated with this rotor design, but the simplicity of the rotor design lends itself to ease of assembly and maintenance and is one of the reasons for its popularity. Aircraft-quality birch was specified in early Bensen designs, and a wood/steel composite is used in the world speed record-holding Wallis design. Gyroplane rotor blades are made from other materials such as aluminum and GRP-based composite.[citation needed]

Bensen's success triggered several other designs, some of them fatally flawed with an offset between the center of gravity and thrust line, risking a Power Push-Over (PPO or bunt-over) causing the death of the pilot and giving gyroplanes, in general, a poor reputation – in contrast to Cierva's original intention and early statistics. Most new autogyros are now safe from PPO.

Certification by national aviation authorities[]

UK certification[]

Some autogyros, such as the Motorsport MT03, MTO Sport (open tandem), and Calidus (enclosed tandem), and the Magni Gyro M16C (open tandem) & M24 (enclosed side by side) have type approval by the United Kingdom Civil Aviation Authority (CAA) under British Civil Airworthiness Requirements CAP643 Section T. Others operate under a permit to fly issued by the Popular Flying Association similar to the US experimental aircraft certification. However, the CAA's assertion that autogyros have a poor safety record means that a permit to fly will be granted only to existing types of autogyros. All new types of autogyro must be submitted for full type approval under CAP643 Section T. Beginning in 2014, the CAA allows gyro flight over congested areas.

In 2005, the CAA issued a mandatory permit directive (MPD) which restricted operations for single-seat autogyros and was subsequently integrated into CAP643 Issue 3 published on 12 August 2005. The restrictions are concerned with the offset between the center of gravity and thrust line and apply to all aircraft unless evidence is presented to the CAA that the CG/Thrust Line offset is less than 2 inches (5 cm) in either direction. The restrictions are summarised as follows:

  • Aircraft with a cockpit/nacelle may be operated only by pilots with more than 50 hours of solo flight experience following the issue of their license.
  • Open-frame aircraft are restricted to a minimum speed of 30 mph (48 km/h; 26 km), except in the flare.
  • All aircraft are restricted to a Vne (maximum airspeed) of 70 mph (110 km/h; 61 kn)
  • Flight is not permitted when surface winds exceed 17 mph (27 km/h; 15 kn) or if the gust spread exceeds 12 mph (19 km/h; 10 kn)
  • Flight is not permitted in moderate, severe, or extreme turbulence and airspeed must be reduced to 63 mph (101 km/h; 55 kn) if turbulence is encountered mid-flight.

These restrictions do not apply to autogyros with type approval under CAA CAP643 Section T, which are subject to the operating limits specified in the approval.