A modern autogyro
An autogyro is a type of rotorcraft invented by Juan de la Cierva in 1919, making its first successful flight on January 9, 1923 at Cuatro Vientos Airfield in Madrid, Spain.[1] The lift for an autogyro is provided by a rotor, similar to that of a helicopter. Unlike a helicopter, the rotor of an autogyro is driven by aerodynamic forces alone, once it is in flight. Thrust for the autogyro is provided by an engine-powered propeller similar to that of a fixed-wing aircraft.

Autogyros are also known as gyroplanes, gyrocopters, or rotaplanes. The term Autogiro was a trademark of the Cierva Autogiro Company and the term Gyrocopter was originally a trademark of Bensen Aircraft.

Principle of operation

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Montgomerie Merlin single-seat autogyro
An autogyro is characterised by a free-spinning rotor that turns due to passage of air upwards through the rotor. The vertical component of the total aerodynamic reaction of the rotor gives lift for the vehicle, and sustains the autogyro in the air. Forward thrust is provided by a separate propeller, or alternately, jet thrust, as used on the Lockheed XH-51A Compound when flying in autogyro mode.

Whereas a helicopter works by forcing the rotor blades through the air, pushing air downwards, the gyrocopter rotor blade generates lift in the same way as a glider's wing by changing the angle of the air as it moves upwards and backwards relative to the rotor blade. The free-spinning blades turn by autorotation; the rotor blades are angled so that they give not only lift, but also so as to accelerate the blades' rotation rate, until the rotor turns at a stable speed with the drag and thrust forces in balance.

Pitch control of the autogyro is by tilting the rotor fore and aft; roll control is by tilting the rotor laterally (side to side). Tilt of the rotor may be effected by a tilting hub (Cierva), swashplate (Air & Space 18A), or servo-flaps (Kaman SAVER). Yaw control is provided by a rudder, usually placed in the propeller slipstream to maximize yaw control at low airspeed.


Early developments

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The first autogyro to fly successfully (1923)
Juan de la Cierva, a Spanish engineer and aeronautical enthusiast, invented the first successful rotorcraft, which he named 'autogiro' in 1923. His aim was to create an aircraft which would not stall, following the stall-induced crash of a three-engine bomber he had designed for a Spanish military aeronautical competition. His craft used a tractor-mounted forward propeller and engine, a rotor mounted on a mast, and a horizontal and vertical stabilizer. His first three designs, C.1, C.2, and C.3, were unstable due to aerodynamic and structural deficiencies in their rotors. His fourth design, the C.4, fitted with flapping hinges to attach each rotor blade to the hub, made the first successful flight of a rotary-wing aircraft, piloted by Alejandro Gomez Spencer, on January 9, 1923. The C.4 was fitted with conventional ailerons, elevators and rudder for control. During a later test flight, the engine failed shortly after takeoff and the aircraft descended slowly and steeply to a safe landing, validating la Cierva's efforts to produce an aircraft that could be flown safely at low airspeeds. Cierva C.6 model was a step forward in the development of autogyros for it was the first one to fly a "major" distance

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Avro-built Cierva C.19 Mk.IV Autogiro, built in 1932. Cuatro Vientos Airport Museum, Madrid, Spain.
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La Cierva C-6 replica in Cuatro Vientos Air Museum, Madrid, Spain

This success eventually became well known and after further limited Autogiro development in Spain, la Cierva accepted an offer from Scottish industrialist James G. Weir to establish the Cierva Autogiro Company in England following a demonstration on 20 October 1925 to the British Air Ministry at RAE Farnborough. Test pilot for these flights was Frank T. Courtney. From this point on, Britain became the world center of rotary-wing aircraft development.

A crash due to blade root failure in February 1927 led to an improvement in rotor hub design. Adjacent the flapping hinge a drag hinge was incorporated to allow each blade to slightly oscillate horizontally and relieve in-plane stresses generated as a byproduct of flapping motion. Development work on means to accelerate the rotor prior to takeoff was also undertaken. Efforts with the C.11 in Spain showed that development of a light and efficient mechanical rotor transmission was not a trivial undertaking and led to the adoption of the intermediate expedient of inclining the horizontal stabilizer to redirect the propeller slipstream into the rotor while on the ground. This feature was later introduced on the production C.19 series of 1929.

Further Autogiro development led to the Cierva C.8 L.IV which on 18 September 1928 made the first rotary-wing aircraft crossing of the English Channel followed by a tour of Europe. The US industrialist Harold Frederick Pitcairn had in 1925 visited la Cierva in Spain upon learning of the successful flights of the Autogiro; in 1928 he visited la Cierva in England after taking a C.8 L.IV test flight piloted by Arthur H.C.A. Rawson and being particularly impressed with the Autogiro's safe vertical descent capability, purchased a C.8 L.IV with a Wright Whirlwind engine. Arriving in the United States on 11 December 1928 accompanied by Rawson, this Autogiro was redesignated C.8W.

The Cierva "Autodynamic" rotor used drag hinges with offset axes to perform this to good effect with great simplicity, but the Pitcairn collective pitch control advanced the "jump" ability.

The C-19 technology was licensed to a number of manufacturers, including Harold Pitcairn in the U.S. (in 1928) and Focke-Achgelis of Germany. In 1931 Amelia Earhart flew a Pitcairn PCA-2 to a then world altitude record of 18,415 feet (5,613 m).

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Cierva Autogiro, at the Imperial War Museum, Duxford, UK.

World War II

In World War II, Germany pioneered a very small gyroglider "rotor-kite", the Focke-Achgelis Fa 330 "Bachstelze" (Water-wagtail), towed by U-boats to provide aerial surveillance.

The Japanese Army developed the Kayaba Ka-1 Autogyro for reconnaissance, artillery-spotting, and anti-submarine uses. The Ka-1 was based on an American design first imported to Japan in 1938. The craft was initially developed for use as an observation platform and for artillery spotting duties. The Army liked the craft's short take-off span, and especially its low maintenance requirements. In 1941 production began, with the machines assigned to artillery units for spotting the fall of shells. These carried two crewmen: a pilot and a spotter.

Later, the Japanese Army commissioned two small aircraft carriers intended for coastal antisubmarine (ASW) duties. The Ka-1 was modified by eliminating the spotter's position in order to carry one small depth charge. Ka-1 ASW autogyros operated from shore bases as well as the two small carriers. They appear to have been responsible for at least one successful submarine sinking.

Postwar developments

The autogyro was resurrected after World War II when Dr. Igor Bensen saw a captured German U-Boat's Fa 330 gyroglider and was fascinated by its characteristics. At work he was tasked with the analysis of the British "Rotachute" gyro glider designed by expatriate Austrian Raoul Hafner. This led him to adapt the design for his own purposes and eventually market the B-7.

Later autogyros, such as the Bensen B-8M gyrocopter, generally use a pusher configuration for simplicity and to increase visibility for the pilot. For greater simplicity, they generally lack both variable-pitch rotors and powered rotors. Bensen autogyros and its derivatives have a poor safety record due to their deficient stability and control characteristics greatly worsened by use of a teetering rotor, and their marketing as a "build it yourself and teach yourself how to fly" aircraft.

In the 1950s and 1960s there was interest in developing a VTOL capability in autogyros while retaining the efficiency of an undriven rotor in horizontal flight. This led to a number of gyrodynes (also called "heliplanes") which were functionally like autogyros during flight but could apply power to the rotor at take off and for hovering.

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

The most popular autogyro designs are based on the B8M Gyrocopter, developed by Igor Bensen in the mid-1950s. Bensen, a Russian immigrant, submitted the B8M for testing to the United States Air Force, which designated it the X-25. The B8M was designed to use surplus McCulloch engines used on flying unmanned target drones.

A miniature autogyro craft, the Wallis autogyro, was developed in England in the 1960s by Ken Wallis and autogyros built to Wallis designs appeared for a number of years. Ken Wallis's designs have been used in various scenarios including military training, police reconnaissance, and in another case a search for the Loch Ness Monster.

Flight controls

There are three primary flight controls: control stick, rudder pedals, and throttle.

The control stick is termed cyclic and tilts the rotor in the desired direction to provide pitch and roll control. The rudder pedals provide yaw control, and the throttle controls engine power.

Secondary flight controls include the rotor transmission clutch which when engaged drives the rotor to start it spinning before takeoff, and collective pitch to reduce blade pitch before driving the rotor. Collective pitch controls are not usually fitted to autogyros, but can be found on the Air & Space 18A and McCulloch J-2.

General characteristics

Autogyros can take off and land in significantly smaller areas than fixed-wing aircraft, and, depending on the model, can operate from helipads. When fitted with a jump takeoff feature, an autogyro can take off from a standing start into forward flight, accelerate while in ground effect, and then climb.

The climb angle after takeoff is relatively shallow, similar to that of a STOL fixed-wing aircraft. Sufficient area must be available after takeoff for the autogyro to turn and avoid obstacles during climb. This limitation, as well as the lack of hovering performance, is primarily responsible for autogyros being superseded by helicopters.

Gyroplanes also cannot fly safely under low-g conditions, such as a pitch-over maneuver commonly used in fixed-wing aircraft, due to excessive loss of rotor rpm and resulting rotor instability. This is particularly a problem with Bensen-type gyroplanes due to their lack of pitch stability and use of a teetering rotor.

It is possible to land an autogyro in an area from which it cannot take off. An autogyro can easily execute a steep approach to a no-roll landing. If rotor collective pitch control is provided, an autogyro can execute a collective flare; otherwise, landings are always made with a cyclic flare.

As intended by la Cierva, the rotor always turns regardless of the airspeed of the aircraft, though as airspeed decreases rotor rpm reduces to a minimum value at zero airspeed. Autogyros cannot hover for more than a few moments at most, since the rotor is de-clutched from its drive before starting the takeoff procedure and its speed decays quickly. Reduction of engine power increases the descent rate, though the autogyro remains fully stable and controllable. Directional control, provided by a rudder, can become non-existent at low airspeed and low propeller thrust. For example, the Air & Space 18A gyroplane rudder rapidly loses effectiveness below 50 mph airspeed when the engine is throttled back.

Most autogyros are neither efficient nor very fast, although Ken Wallis has achieved 120 mph from 60 bhp in one of his designs. More recently the CarterCopter achieved a speed of 170 mph. Fixed-wing aircraft are faster and use less fuel over the same distance, while helicopters generally require more power (and hence more fuel) than either fixed wing aircraft or autogyros for the same speed and load. Autogyro development ceased before World War II, and with few exceptions, has not benefited from modern rotary wing advances applied to helicopters. When improvements in helicopters made them practical, autogyros became largely neglected. They were, however, used in the 1930s by major newspapers, and by the US Postal Service for mail service between the Camden, NJ airport (USA) and the top of the post office building in downtown Philadelphia, Pennsylvania (USA). [2] Autogyros can be of tractor configuration (with the engine(s) and propeller(s) at the front of the fuselage), e.g., Cierva, or pusher configuration (with the engine(s) and propeller(s) at the rear of the fuselage), e.g., Bensen. Early autogyros were fitted with fixed rotor hubs, small fixed wings, and control surfaces like those of a fixed wing aircraft. These designs were problematic, because at low airspeeds, the control surfaces became ineffective and could readily lead to loss of control, particularly during landing. The direct control rotor hub, which could be tilted in any direction by the pilot, was first developed on the Cierva C.19 Mk. V and saw production on the Cierva C.30 series of 1934.

Rotor drives initially took the form of a rope wrapped around the rotor axle and then pulled by a team of men to accelerate the rotor - this was followed by a long taxi to bring the rotor up to speed sufficient for takeoff. The next innovation was a fully deflectable horizontal stabilizer that directed propeller slipstream into the rotor. Cierva {license?}, Pitcairn-Cierva Autogiro Company of Willow Grove, Pennsylvania, finally solved the problem with a light mechanical transmission driven by the engine.

The Groen Brothers Hawk 4 design of 1992 is advertised as possessing "Ultra-Short Take-Off and Landing" (USTOL) capability, enabling the aircraft to take off and land within a very short distance (25 feet). This is merely a new name for performance autogyros have always possessed.

Flight characteristics

Flight in any rotorcraft can be summed up as feeling similar to a cork bobbing on the sea. The rotor sweeps a large area and though it is very effective at damping out disturbances, it provides a somewhat nautical element to the flying qualities. Moving the cyclic stick tilts the entire rotor to a new position within no more than about one revolution and is thus a very sensitive control. There is nevertheless a small time lag between cyclic stick movement and aircraft response since the control system is essentially a mechanical relay system that only indirectly tilts the rotor: the cyclic control merely establishes the conditions for aerodynamic forces to reorient the rotor in the desired direction. Additionally, since the rotor is always turning at or above a minimum r.p.m., control sensitivity does not vary significantly with changes in airspeed.

Effectiveness of the rudder is dependent on airflow, and it rapidly loses authority as airspeed decreases; this can be partially offset by maintaining propeller thrust to generate the required airflow at low airspeeds.

US certification

A certificated autogyro must meet mandated stability and control criteria; in the United States these are set forth in Federal Aviation Regulations Part 27: Airworthiness Standards: Normal Category Rotorcraft. Such autogyros are issued a Standard Airworthiness Certificate by the US Federal Aviation Administration. Bensen-type autogyros are generally home built, either from plans or from a kit. Home-built aircraft are operated under a Special Airworthiness Certificate in the Experimental category, so there is no guarantee they will perform as claimed by their manufacturers. It is important to note that Bensen-type autogyros have a poor safety record - this is due to two factors: (1) significant stability and control deficiencies inherent in the design, and (2) an unfortunate record of this type of autogyro being flown by unqualified / untrained pilots. NTSB accident records give a clear picture of the safety of autogyros with Standard Airworthiness Certificates compared to those with Special Airworthiness Certificates.

UK certification

In 2005 the United Kingdom Civil Aviation Authority (CAA) issued a mandatory permit directive (MPD) which restricts operations for single seat autogryos. The MPD is concerned with the offset between the centre of gravity and thrust line, and apply to all aircraft unless evidence is presented to the CAA that the CG/Thrust Line offset less than 2 inches (5 cm) in either direction. The restrictions, which are considered oppressive by many in the UK autogryo community, are summarised as follows:
  • Aircraft with a cockpit/nacelle may only be operated by pilots with more than 50 hours solo flight experience following the issue of their licence.
  • Open frame aircraft are restricted to a minimum speed of 30 mph (26 knots), except in the flare.
  • All aircraft are restricted to a Vne of 70 mph (61 knots)
  • Flight is not permitted when surface winds exceed 17 mph (15 knots) or if the gust spread exceeds 12 mph (10 knots)
  • Flight is not permitted in moderate, severe or extreme turbulence and airspeed must be reduced to 63 mph (55 knots) if turbulence is encountered mid-flight.

Bensen's design

The Bensen Gyrocopter was adapted directly from the Hafner Rotochute and Focke-Achgelis Fa 330A-1 "Bachstelze" autogiros of World War II. Bensen's adaptation, termed Gyrocopter, was available in three versions, B-6, B-7 and B-8. All three were designed in both unpowered and powered forms.

The basic Bensen Gyrocopter design is a simple frame of square aluminium 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.

Power can be supplied by a variety of engines, though rarely one certificated for use in aircraft. McCulloch drone engines, Rotax, and other designs have been used in Bensen-type designs.

The rotor is atop the vertical mast. Outlying mainwheels are mounted on an axle. A front-to-back keel mounts a steerable nosewheel, seat, other tubes, engine, a vertical stabilizer, and commonly a small fixed tailwheel. Some versions mount seaplane-style floats for water operations.

Many light gyroplane rotors are made from aluminium, though GRP-based composite blades (Sport Copter, Averso, Revolution, RAF eg) and GRP-skinned blades are increasing in number. Aircraft-quality birch was specified in early Bensen designs, and a wood/steel composite is still used in the world speed record holding Wallis design.

The rotor system of all Bensen-type autogyros is of two-blade teetering design. This single feature is responsible for the majority of accidents in this type of autogyro due its lack of tolerance for mishandling. A teetering rotor does not directly control the fuselage attitude but merely reorients the thrust vector which then causes the fuselage to swing into alignment beneath it. If a low G condition occurs, rotor thrust decreases and causes degradation of control. A certificated rotorcraft fitted with a teetering rotor is required by airworthiness standards to maintain a loading of at least 0.5G. If the rotor is powered as in a helicopter, rotor RPM is maintained even though control authority decays; in the case of an autogyro, rotor RPM and control degrade simultaneously and prompts the usually "self-trained" pilot to over control and precipitate contact between the rotor and the rudder.

All autogiros produced by the Cierva Autogiro Company and its licensees were fitted with articulated rotors controlled about a tilting hub. This design has significantly higher tolerance to mishandling due to offset flapping hinges which generate a control moment even under low G conditions and provides control of the rotor. Over control of this rotor can still result in contact with part of the fuselage however. Unlike the majority of Bensen-type autogyros, Cierva Autogiros were invariably flown by trained and qualified pilots, which produced a safety record not exceeded in general aviation until 1972.

Bensen-type designs commonly also have an unstable relationship between propeller thrust line, aircraft center-of-gravity, and rotor drag. If the propeller thrust line passes above the aircraft center-of-gravity and rotor drag decreases suddenly, the Gyrocopter goes out of balance and pitches down rapidly. This has the additional effect of unloading the rotor. This condition is unrecoverable and has caused many fatalities.

The thrust line of autogiros produced by the Cierva Autogiro Company and its licensees passed through the aircraft center-of-gravity, thus eliminating any pitching moment due to reduction of rotor drag.


The Bensen design has also been used by hobbyists, sight-seers and scientists (for game counting).


As of 2002, Wing Commander Ken Wallis, an enthusiast who has built several autogyros, holds or has held most of the type's record performances. These include the speed record of 111.7 mph (186 km/h), and the straight-line distance record of 543.27 miles (905 km). The record picture is continually changing, and on 16 November 2002, Ken Wallis increased the speed record to 207.7 km/h - and simultaneously set another world record as the oldest pilot to set a world record.[3]


Andy Keech made a transcontinental flight from Kitty Hawk, N.C. to San Diego, Ca. in October 2003 and set 3 world records. The 3 records are for 'speed over a recognised course', and are verified by tower personnel or by official observers of the U.S. National Aeronautic Association. In February 2006 he set further world speed records, ratified by the Fédération Aéronautique Internationale (FAI):
  • Sub-class : E-3a (Autogyros : take-off weight less than 500 kg)
Category : General
Group 1 : piston engine
  • Speed over a closed circuit (500km) without payload : 168.29 km/h,
::Date of flight: 09 February 2006
::Pilot: Andrew C. KEECH (USA)
::Course/place: North Little Rock, AR (USA)
  • Sub-class : E-3a (Autogyros : take-off weight less than 500 kg)
Category : General
Group 1 : piston engine
  • Speed over a closed circuit (1000km) without payload : 165.07 km/h,
::Date of flight: 09 February 2006
::Pilot: Andrew C. KEECH (USA)
::Course/place: North Little Rock, AR (USA)

The CarterCopter fixed wing/autogyro hybrid has been unofficially flown in tests at speeds above 170 mph. The theoretical top speed for this general design exceeds 450 mph.
In the late 1950s, the (15 tonne) Fairey Rotodyne, a gyrodyne hybrid was capable of 213 mph.


(as ratified by FAI)
  • Sub-class E-3b (Autogyros : take-off weight 500 to 1,000 kg)
Category : General
Group 1 : piston engine
  • Distance over a closed circuit without landing : 1 019.09 km
::Date of flight: 09/02/2006
::Pilot: Andrew C. KEECH (USA)
::Course/place: North Little Rock, AR (USA)


Many autogyros are assembled from kits. Kit vendors often say that since it has few parts, hobbyists can assemble it more rapidly and correctly than most fixed-wing kit aircraft. Kits with all parts, ready to assemble, are listed for US$19,550 as of 18 July 2002. This is inexpensive for an aircraft and includes an engine.

Some people who have completed an autogyro have said that it took them about a year, working in their spare time. Estimates place most build times at 100 to 200 hours.


Most vendors recommend that a new pilot have at least ten hours of instruction by a rated instructor in small fixed-wing aircraft, followed by at least two hours of instruction in a dual-place autogyro with an experienced instructor. An autogyro is more similar to a fixed-wing aircraft than to a helicopter.

Autogyros are relatively safe, but not foolproof. There were 19 fatal autogyro accidents reported to the FAA between 1996 and 2001, and many more serious injuries. Safety precautions, training, instrumentation, flight rules, preflight checklists, and periodic inspections and maintenance must not be neglected.

There is a slight delay between control input and aircraft response - a characteristic of inertia in the spinning rotor blades. Inexperienced pilots may be inclined to repeat or overemphasise a control input owing to a perceived lack of response. The resulting response may then be excessive and the pilot may attempt to compensate with opposing inputs, again with excessive control motion. These inputs can quickly put the aircraft into an increasing cycle of responses which may exceed the safe flying limits. This phenomenon is termed "Pilot-induced oscillation" (PIO), and has led to loss of control crashes and fatalities. PIO is readily corrected in a certificated autogyro operated by a trained pilot; in a Bensen-type autogyro no amount of training may be sufficient to avoid catastrophe.

In the United States, private, recreational, and commercial pilot licenses with rotorcraft category and gyroplane class rating are issued, or the rating is added to an existing license for other aircraft; holders of sport pilot licenses can also qualify to fly autogyros. Requirements include completing required training times, passing written exams, and successfully doing oral and practical tests. Sport pilot license in-flight tests can be conducted in single-seat aircraft, but a "single place only" limitation is placed on the certificate in such cases.

"Learning to fly the rotor" is a vital ingredient for safe flight in an autogyro - models and rotary kites can help the learning process, and towed gyro-gliders and boom-trainers are ideal tools for this as well as being cheap to build and fly.

Autogyros in popular culture

An indication of the pre-war popularity of the autogyro, its subsequent decline and later rise of interest can be inferred from its appearances in the films and comics of the day. Notable appearances include:
  • In "International House" (1933) W.C. Field's character converts his golf cart to an autogyro and takes off from the fairway, subsequently crashing into a hotel roof garden.
  • Little Nellie, the autogyro featured in the 1967 James Bond film You Only Live Twice, was a Ken Wallis WA-116 design and was piloted by Wallis in its film scenes.[4][5]
  • An autogyro was heavily featured in the second Mad Max (The Road Warrior) film, released in 1981, appearing in several scenes with its pilot, the Gyro Captain, as a major character. The pilot used in the flying sequences was Gerry Goodwin, doubling for the actor Bruce Spence.[6]
  • Fictional comic characters Doc Savage,[7] The Shadow, and Tom Strong[8] all featured autogyro in their 1930s and '40s pulp magazine adventures.
  • Batman's first aircraft was an autogyro. The "Batgyro" was introduced in Detective Comics #31 in September 1939. It only made three appearances before being replaced by a more conventional fixed wing aircraft.
  • In The Simpsons episode "22 Short Films About Springfield", Mr. Burns is seen reading a magazine called Autogyro Enthusiast. In the episode "Mother Simpson", Mr. Burns, in the post office with Mr. Smithers, says, "Yes, I'd like to send this letter to the Prussian consulate in Siam by aeromail. Am I too late for the 4:30 autogyro?"

See also


1. ^ Vector Flight
2. ^ Pulle, Matt (5 July 2007), "Blade Runner", Dallas Observer (Dallas, Tx) Vol. 27 (Issue 27): pp. 19–27, <[1]
3. ^ List of records established by Kenneth H. Wallis. Fédération Aéronautique Internationale. Retrieved on 2007-10-07.
4. ^ Trivia: You Only Live Twice. Internet Movie Database. Retrieved on 2007-10-07}}.
5. ^ K.H. Wallis. Internet Movie Database. Retrieved on 2007-10-07}}.
6. ^ Gerry Goodwin. Internet Movie Database. Retrieved on 2007-10-07.
7. ^ Doc piloting his gyro. Art Nocturne. Retrieved on 2007-10-07.
8. ^ Tom Strong and his Phantom Autogyro. America's Best Comics. Retrieved on 2007-10-07.

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Rotorcraft is a category of heavier-than-air flying machines that use lift generated by wings that revolve around a mast called rotor blades. Several rotor blades mounted to a single mast is referred to as a rotor.
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Juan de la Cierva (21 September 1895 – 9 December 1936) was a Spanish civil engineer and pilot. His most famous accomplishment was the invention in 1919 of the Autogiro, a type of aircraft that later came to be called an autogyro.
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January 9 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.


  • 475 - Byzantine Emperor Zeno is forced to flee his capital at Constantinople.

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Puerta de Alcalá at night with El Retiro gardens in the background.

Coat of arms
Motto: De Madrid al Cielo
(Spanish for "From Madrid to Heaven")
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The lift force, lifting force or simply lift is a mechanical force generated by solid objects as they move through a fluid.[1]

While many types of objects can generate lift, the most common and familiar object in this category is the airfoil, a
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helicopter is an aircraft which is lifted and propelled by one or more horizontal rotors, each rotor consisting of two or more rotor blades. Helicopters are classified as rotorcraft or rotary-wing aircraft to distinguish them from fixed-wing aircraft because the helicopter derives
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Thrust is a reaction force described quantitatively by Newton's Second and Third Laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a proportional but opposite force on that system.
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fixed-wing aircraft is a heavier-than-air craft where movement of the wings in relation to the aircraft is not used to generate lift. The term is used to distinguish from rotary-wing aircraft, or ornithopters, where the movement of the wing surfaces relative to the aircraft
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trademark or trade mark[1] is a distinctive sign or indicator of some kind which is used by an individual, business organization or other legal entity to uniquely identify the source of its products and/or services to consumers, and to distinguish its products or
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Juan de la Cierva (21 September 1895 – 9 December 1936) was a Spanish civil engineer and pilot. His most famous accomplishment was the invention in 1919 of the Autogiro, a type of aircraft that later came to be called an autogyro.
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The Bensen Aircraft Corporation was established by Dr Igor Bensen at Raleigh-Durham International Airport in North Carolina in 1952 to develop and market a variety of helicopters and autogyros of Bensen's own design.
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Lockheed XH-51 was an experimental helicopter design by Lockheed utilizing a rigid rotor. Lockheed's design, Model 186, was selected for a US military requirement for a high-speed, research helicopter.
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Gliders or Sailplanes are heavier-than-air aircraft primarily intended for unpowered flight. See also gliding and motor gliders for more details.[1]


A "glider" is an unpowered aircraft.
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swashplate is a device that translates the pilot's (or autopilot's) commands via the helicopter flight controls into motion of the main rotor blades. Because the main rotor blades are spinning, the swashplate is used to transmit three of the pilot's commands from the non-rotating
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Type Autogyro
Manufacturer Air and Space Manufacturing, Inc.
Designed by Raymond E. Umbaugh
Maiden flight 1964
Introduced 1965
Status Out of production
Produced 1965-2000
Number built 68
Unit cost
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rudder is a device used to steer ships, boats, submarines, aircraft, hovercraft or other conveyances that move through air or water. Rudders operate by re-directing the flow of air or water past the hull or fuselage, thus imparting a turning or yawing motion to the craft.
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The word yaw can refer to:
  • Yaw angle, any horizontal angle; used in sailing, navigation, aeronautics and flight dynamics. Angles in the other two directions are called "pitch" and "roll".

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Juan de la Cierva (21 September 1895 – 9 December 1936) was a Spanish civil engineer and pilot. His most famous accomplishment was the invention in 1919 of the Autogiro, a type of aircraft that later came to be called an autogyro.
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"Plus Ultra"   (Latin)
"Further Beyond"
"Marcha Real" 1
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For other uses, see stall.

In aerodynamics, a stall is a sudden reduction in the lift forces generated by an airfoil. This most usually occurs when the critical angle of attack for the airfoil is exceeded.
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La Cierva C-6 was the sixth autogyro constructed by engineer Juan de la Cierva, and the first one to travel a "major" distance. De la Cierva, the engineer responsible for the invention of the autogyro, spent all his funds in the research and creation of his first five prototypes.
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"God and my right"
No official anthem specific to England — the anthem of the United Kingdom is "God Save the Queen".
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19th century - 20th century - 21st century
1890s  1900s  1910s  - 1920s -  1930s  1940s  1950s
1922 1923 1924 - 1925 - 1926 1927 1928

Year 1925 (MCMXXV
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Air Ministry was formerly a department of the British Government with the responsibility of managing the affairs of the Royal Air Force.

Organizations before the Air Ministry

The Air Committee

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The Royal Aircraft Establishment (RAE) England, was a British research establishment latterly under the UK Ministry of Defence (MOD)

The first site was at Farnborough Airfield ("RAE Farnbrough") in Hampshire to which was added a second site RAE Bedford.
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September 18 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.


  • 96 - Nerva is proclaimed Roman Emperor after Domitian is assassinated.

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19th century - 20th century - 21st century
1890s  1900s  1910s  - 1920s -  1930s  1940s  1950s
1925 1926 1927 - 1928 - 1929 1930 1931

Year 1928 (MCMXXVIII
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English Channel (French: La Manche, "the sleeve") is an arm of the Atlantic Ocean that separates the island of Great Britain from northern France and joins the North Sea to the Atlantic.
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