Inglês/Português
<< autopilot | autorotation | autothrottle >>
Back to: "A"autorotation
- Definição1
- (1) A condition in which a rotor of a helicopter is driven solely by the action of air ascending through its blades rather than by engine power. In helicopters, descending with the power off, air flows in the reverse direction upward through the main rotor, causing it to continue rotating at cruising RPM. To maintain the rotor RPM, the helicopter is allowed to descend by lowering the collective lever so that the relative airflow strikes the blade in a manner in which the airflow itself provides the driving force. Under these conditions, the rate of descent becomes the power equivalent, and the helicopter is said to be in a state of autorotation. The angle of descent in an autorotation is very steep. Autorotation landings are practiced to train pilots to enable them to land in case of actual engine failure. Various expressions used by pilots while carrying out autorotations are autorotative landing, touchdown autorotation, or autorotation to touchdown. All these mean that the pilot will land without applying power to the rotor. A 180º autorotation means one initiated from a downwind heading, with a turn into the wind; it commences well inside the normal traffic pattern. Low-level autorotation commences at an altitude well below the traffic pattern, usually below 100 ft AGL (above ground level), and is primarily used for tactical military training. (2) The rotation of aircraft around its axes resulting from aerodynamic forces. An aircraft in spin autorotates (autorolls, autoyaws, and autopitches) because of aerodynamic forces. (3) The tendency of an airfoil at high angles of attack to rotate to align with the relative airflow.
- Fonte1
- KUMAR, Bharat (ed.). An illustrated dictionary of aviation. New York: McGraw-Hill, c2005. 752 p.
- Definição2
- The property of a rotor system to maintain its angular velocity without engine power, the relative force provided by the forward component of the lift forces, acting on the rotor blades.
- Fonte2
- SCHAFER, Joe. Helicopter maintenance. Englewood: Jeppesen Sanderson, Inc., c2007. viii, 343 p.
- Definição3
- The condition of flight during which the main rotor is driven only by aerodynamic forces with no power from the engine.
- Fonte3
- FEDERAL AVIATION ADMINISTRATION. Rotorcraft flying handbook (FAA-H-8083-21). Washington, DC: FAA, 2000. Disponível em: http://www.faa.gov/library/manuals/aircraft/media/faa-h-8083 -21.pdf. Acesso em: 10 fev. 2012.
- Fonte4
- AGÊNCIA NACIONAL DE AVIAÇÃO CIVIL. RBAC 01: regulamentos brasileiros de aviação civil. Definições, regras de redação e unidades de medida. Brasília, 2008. (Regulamentos Brasileiros de Aviação Civil).
- Subárea1
- Rotorcraft
- Related Term
- straight-in autorotation
- Português
- autorrotação
- Imagem
During an autorotation, the upward flow of relative wind permits the main rotor blades to rotate at their normal speed. In effect, the blades are “gliding” in their rotational plane.
Fonte: http://en.wikipedia.org/wiki/File:Airflow_in_auto-2.jpg
