直升机教员手册 Helicopter Instructor’s Handbook
时间：2014-11-10 08:35来源：FAA 作者：直升机翻译 点击：次
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To view this page ensure that Adobe Flash Player version 9.0.124 or greater is installed. Lateral vibration. A vibration in which the movement is in a lateral direction, such as imbalance of the main rotor. Lead and flag. The fore (lead) and aft (lag) movement of the rotor blade in the plane of rotation. Licensed empty weight. Basic empty weight plus only undrainable oil. Lift. One of the four main forces acting on a rotorcraft. It acts perpendicular to the relative wind. Load factor. The ratio of a specified load to the total weight of the aircraft. Loss of Tail Rotor Effectiveness (LTE). A manifestation of the Vortex ring aerodynamics on a vertical rotating wing, anti-torque rotor in most instances. Usually inertia and winds combine with Vortex ring state aerodynamics to constitute the hazard. It is characterized by a loss of heading control and requires flight to gain airspeed to exit the phenomenon. Low-G Maneuvers. A low-G condition is a phase of aerodynamic flight where the airframe is temporarily unloaded and the rotor is not supporting the weight of the helicopter. This usually occurs during low gravity or negative gravity maneuvers. This allows tail rotor thrust to tilt the airframe prompting the pilot to add lateral cyclic which is a fatal movement. Helicopter pilots experiencing less than one gravity of force should first apply aft cyclic to reload the rotor system with the weight of the helicopter. Married needles. A term used when two hands of an instrument are superimposed over each other, as on the engine/rotor tachometer. Mast. The component that supports the main rotor. Mast bumping. Action of the rotor head striking the mast, occurring on only underslung rotors. Navigational aid (NAVAID). Any visual or electronic device, airborne or on the surface, that provides point-to-point guidance information, or position data, to aircraft in flight. Negative transfer. When previously learned procedures, techniques, and judgment may lead to negative outcomes or poor results in a different environment, or in some cases, a different type aircraft or different category of aircraft. Night. The time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac. Normally aspirated engine. An engine that does not compensate for decreases in atmospheric pressure through turbocharging or other means. One-to-one vibration. A low-frequency vibration having one beat per revolution of the rotor. This vibration can be either lateral, vertical, or horizontal. Out-of-ground-effect (OGE) hover. A hover greater than one rotor diameter distance above the surface. Because induced drag is greater while hovering out of ground effect, it takes more power to achieve a hover out of ground effect. Parasite drag. The part of total drag created by the form or shape of helicopter parts. Payload. The term used for passengers, baggage, and cargo. Pendular action. The lateral or longitudinal oscillation of the fuselage due to its suspension from the rotor system. Pitch angle. The angle between the chord line of the rotor blade and the reference plane of the main rotor hub or the rotor plane of rotation. Pressure altitude. The height above the standard pressure level of 29.92 "Hg. It is obtained by setting 29.92 in the barometric pressure window and reading the altimeter. Profile drag. Drag incurred from frictional or parasitic resistance of the blades passing through the air. It does not change significantly with the angle of attack of the airfoil section, but it increases moderately as airspeed increases. Resultant relative wind. Airflow from rotation that is modified by induced flow. Retreating blade. Any blade, located in a semicircular part of the rotor disk, in which the blade direction is opposite to the direction of flight. Retreating blade stall. A stall that begins at or near the tip of a blade in a helicopter because of the high angles of attack required to compensate for dissymmetry of lift. Rigid rotor. A rotor system permitting blades to feather but not flap or hunt. Rotational velocity. The component of relative wind produced by the rotation of the rotor blades. Rotor. A complete system of rotating airfoils creating lift for a helicopter. Rotor disk area. See disk area. Rotor brake. A device used to stop the rotor blades during shutdown. Rotor force. The force produced by the rotor. It is composed of rotor lift and rotor drag. Semirigid rotor. A rotor system in which the blades are fixed to the hub, but are free to flap and feather. Settling with power. A condition of a rotor experiencing vortex ring state. The term describes how the helicopter keeps losing altitude, or settling, even though adequate engine power is available for flight. It is characterized by a rate of descent of more than 300 feet per minute, less than effective translational lift (around 15 knots), and 20 percent to 100 percent of engine power applied to the rotor system. See vortex ring state. Shaft turbine. A turbine engine used to drive an output shaft, and commonly used in helicopters. Skid. A flight condition in which the rate of turn is too great for the angle of bank. Skid shoes. Plates attached to the bottom of skid landing gear, protecting the skid. Slip. A flight condition in which the rate of turn is too slow for the angle of bank. Solidity ratio. The ratio of the total rotor blade area to total rotor disk area. Span. The dimension of a rotor blade or airfoil from root to tip. Split needles. A term used to describe the position of the two needles on the engine/rotor tachometer when the two needles are not superimposed. Standard atmosphere. A hypothetical atmosphere based on averages in which the surface temperature is 59 °F (15 °C), the surface pressure is 29.92 "Hg (1,013.2 mb) at sea level, and the temperature lapse rate is approximately 3.5 °F (2 °C) per 1,000 feet. Static stop. A device used to limit the blade flap, or rotor flap, at low rpm or when the rotor is stopped. |
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