If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user

 Actions

Gyroplane

From SKYbrary Wiki

Article Information
Category: General General
Content source: SKYbrary About SKYbrary
Content control: SKYbrary About SKYbrary

Gyrocopter

Definition

A gyroplane is an aircraft that achieves lift by means of a free spinning rotor.

Description

Unlike a helicopter which has a powered rotor, the rotor of a gyroplane spins in flight due to the air loading on the rotor blades (aerofoils) as the aircraft moves forward. The free spinning rotor of a gyroplane does not require an anti-torque device, such as a tail rotor, as there is no torque load as would be associated with a powered rotor. The most common gyroplane configurations are comprised of an airframe with landing gear, a single rotor which, in general, has either two or three blades, a propulsion engine and propeller in either pusher or tractor (puller) configuration, and an aircraft style tail assembly with a vertical fin and rudder, and a horizontal stabiliser and elevator. The rudder and elevator flight controls work essentially the same as those of a conventional aircraft. A wing may be included in the design to enhance performance.

Autorotation

A fundamental difference between helicopters and gyroplanes is that in powered flight, a gyroplane rotor system operates in autorotation. In other words, the rotor spins freely as a result of air flowing up through the blades, rather than using engine power to turn the blades and draw air down from above. Forces are created during autorotation that keep the rotor blades turning, as well as creating lift to keep the aircraft aloft. Aerodynamically, the rotor system of a gyroplane in normal flight operates like a helicopter rotor during an engine-out forward autorotative descent.

Prerotator

Prior to takeoff, the gyroplane rotor must first achieve a rotor speed sufficient to create the necessary lift. On very basic gyroplanes, this is accomplished by initially spinning the blades by hand. The aircraft is then taxied with the rotor disc tilted aft, allowing the airflow through the system to accelerate it to the required speed for flight. More advanced gyroplanes use a prerotator, which is driven mechanically, electrically or hydraulically to provide the means to spin the rotor. Note that these types of prerotators can only be used on the ground as the torque that they create must be overcome by the friction between the gyroplane's undercarriage and the surface. In a very few cases, jets mounted on the tips of the rotor blades have been used to prerotate the rotor. Many prerotators are capable of only achieving a portion of the rotor speed necessary for flight; the remainder is gained by taxiing or during the takeoff roll. However, some prerotator systems are robust enough to achieve rotor speed in excess of that required for flight with enough inertia to sustain the rotor speed through a "jump" or vertical takeoff and acceleration profile.

Gyroplane Operating, Handling and Flight Characteristics

It is well beyond the scope of the SKYbrary mandate to provide operating methodology, evaluate the fight characteristics or to suggest handling techniques for specific aircraft types. The FAA Rotorcraft manual listed under Further Reading below contains a wealth of information on these subjects.

Related Articles

Further Reading

FAA