Question

A helicopter has a large main rotor that rotates in a horizontal plane and provides lift. There is also a small rotor in the tail that rotates in a vertical plane. What is it for? (Hint: If there was no tail rotor, what would happen when the pilot altered the angular speed of the main rotor?) Some helicopters do not have a tail rotor but have two large main rotors that rotate in a horizontal plane. Why is it important for the two main rotors to rotate in opposite directions?

Answer 1

The small rotor in the tail has two purposes –

(a) It prevents the helicopter fuselage from turning in circles continuously.

(b) It is also used to control the helicopter’s direction when it is being flown.

Two main rotors rotating in opposite direction has the purpose to neutralize the action created by one motor. Because as per Newton’d third law of motion, for every action there is an equal and opposite reaction. The two main rotors do the same work as the work do by head and tail rotors.