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A Bell UH-1 Iroquois helicopter. A helicopter is a powered rotorcraft with rotors driven by the engine(s) throughout the flight, allowing it to take off and land vertically, hover, and fly forward, backward, or laterally. Helicopters have several different configurations of one or more main rotors.
Abrasion strips on helicopter rotor blades are made of metal, often titanium or nickel, which are very hard, but less hard than sand. When a helicopter flies low to the ground in desert environments, sand striking the rotor blade can cause erosion. At night, sand hitting the metal abrasion strip causes a visible corona or halo around the rotor ...
The Mil Mi-8 is the most produced rotorcraft. Rotorcraft, or rotary-wing aircraft, use a spinning rotor with aerofoil cross-section blades (a rotary wing) to provide lift. Types include helicopters, autogyros, and various hybrids such as gyrodynes and compound rotorcraft. Helicopters have a rotor turned by an engine-driven shaft. The rotor ...
Any rotor system has a delay between the point in rotation where the controls introduce a change in pitch and the point where the desired change in the rotor blade's flight occurs. This difference is caused by phase lag, often confused with gyroscopic precession. A rotor is an oscillatory system that obeys the laws that govern vibration—which ...
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically , to hover , and to fly forward, backward and laterally.
All three classes have been studied for use as lifting rotors and several variations have been flown on full-size aircraft, although only the vertical-axis rotary wing has become widespread on rotorcraft such as the helicopter. Some types provide lift at zero forward airspeed, allowing for vertical takeoff and landing (VTOL), as in the helicopter.
Since the rotors can be configured to be more efficient for propulsion (e.g. with root-tip twist) and it avoids a helicopter's issues of retreating blade stall, the tiltrotor can achieve higher cruise speeds and takeoff weights than helicopters. A tiltrotor aircraft differs from a tiltwing in that only the rotor pivots rather than the entire wing.
A multirotor [1] or multicopter is a rotorcraft with more than two lift-generating rotors. An advantage of multirotor aircraft is the simpler rotor mechanics required for flight control. An advantage of multirotor aircraft is the simpler rotor mechanics required for flight control.