Question

How are the aerodynamic forces of the rotor controlled?

(a) Feathering motion

(b) Lag motion

(c) Flap motion

(d) Yaw motion

The question was posed to me in an interview for job.

This question is from Helicopter Rotor and Notations topic in section Helicopter Dynamics of Aerodynamics

Answer 1

Correct answer is (a) Feathering motion

Easiest explanation: The aerodynamic forces of the rotor is controlled using the pitch motion which helps in altering the angle of attack of the rotor blade. The change of blade pitch angle is known as feathering motion. This is achieved using hinge or bearing but for rotors without hinge, it is accomplished by the pitch moment about the torsional rigidity region at the rotor blade root.