What is the angle of incidence in relation to a rotor blade?

The angle of incidence refers to the angle between the chord line of the rotor blade and the rotor hub. This angle is crucial in determining the aerodynamic forces acting on the blade. Specifically, it influences the lift generated by the rotor blade as it rotates. By adjusting the angle of incidence, a pilot can control the amount of lift produced during flight.

In a helicopter, the main rotor system has blades that rotate around the hub, and the angle of incidence is adjusted during flight through the cyclic and collective controls. This ability to modify the angle allows pilots to maintain control of the helicopter's altitude and attitude, making it a fundamental aspect of rotorcraft aerodynamics.

Other options do not accurately describe the angle of incidence. The second choice refers to the angle in relation to the ground, which is not relevant to the incidence of the blade. The third option describes the relationship between the leading and trailing edges but does not define the angle of incidence itself. The fourth choice pertains to the relative position of rotor blades during rotation, which also does not relate directly to the concept of angle of incidence.