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Its comprises helicopter aerodynamics, stability, control, structural dynamics, vibration, and aeroelastic and aeromechanical stability. [1] By studying the forces in helicopter flight, improved helicopter designs can be made, though due to the scale and speed of the dynamics, physical testing is non-trivial and expensive.
The FAA states "The height–velocity diagram or H/V curve is a graph charting the safe/unsafe flight profiles relevant to a specific helicopter. As operation outside the safe area of the chart can be fatal in the event of a power or transmission failure it is sometimes referred to as the dead man's curve."
[1] [2] Unlike fixed-wing aircraft, of which the stall occurs at relatively low flight speed, the dynamic stall on a helicopter rotor emerges at high airspeeds or/and during manoeuvres with high load factors of helicopters, when the angle of attack(AOA) of blade elements varies intensively due to time-dependent blade flapping, cyclic pitch and ...
Military helicopters are a significant part of the helicopter market In 2017, 926 civil helicopters were shipped for $3.68 billion, led by Airbus Helicopters with $1.87 billion for 369 rotorcraft, Leonardo Helicopters with $806 million for 102 (first three-quarters only), Bell Helicopter with $696 million for 132, then Robinson Helicopter with ...
For a helicopter that is hovering, the aerodynamic force is vertical and exactly balances the helicopter weight, with no lateral force. The downward force on the air flowing through the rotor is accompanied by an upward force on the helicopter rotor disk. The downward force produces a downward acceleration of the air, increasing its kinetic energy.
Helicopters with fly-by-wire systems allow a cyclic-style controller to be mounted to the side of the pilot seat. The cyclic is used to control the main rotor in order to change the helicopter's direction of movement. In a hover, the cyclic controls the movement of the helicopter forward, back, and laterally.
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In helicopter aerodynamics, the Lock number is the ratio of aerodynamic forces, which act to lift the rotor blades, to inertial forces, which act to maintain the blades in the plane of rotation. [1] It is named after C. N. H. Lock , a British aerodynamicist who studied autogyros in the 1920s.