Question

Why are twin rotor configuration used?

(a) To generate more lift

(b) To counter torques

(c) To generate pitching motion

(d) To generate yaw motion

I got this question in an international level competition.

I want to ask this question from Helicopter Rotor and Notations topic in portion Helicopter Dynamics of Aerodynamics

Answer 1

The correct choice is (c) To generate pitching motion

For explanation: A twin rotor configuration is used in a helicopter to counter the torque generated by the main rotor. The rotors are counterrotating with equal size and loading. This leads to no net yaw motion which can be detrimental.