A pedal turn to the right requires ______ power than a pedal turn to the left.

A pedal turn to the right requires ______ power than a pedal turn to the left.

• A. more
• B. less
• C. the same
• D. no power

Answer: (B)

Yaw control on a single-rotor helicopter is achieved by varying tail-rotor thrust to counter the main-rotor torque. When you command a pedal turn, you change the tail-rotor thrust to create the desired yaw moment, and the power needed for a given yaw rate depends on how efficiently the tail rotor converts that power into thrust. In a turn to the right, the tail rotor sits in the main rotor’s downwash, so it sees faster, more energetic airflow. That increases its thrust per unit of power, letting you achieve the same yaw rate with less power. In a left turn, the tail rotor is in cleaner air with less downwash, so it’s less efficient and you need more power for the same yaw rate. Hence a pedal turn to the right requires less power than a pedal turn to the left.

Yaw control on a single-rotor helicopter is achieved by varying tail-rotor thrust to counter the main-rotor torque. When you command a pedal turn, you change the tail-rotor thrust to create the desired yaw moment, and the power needed for a given yaw rate depends on how efficiently the tail rotor converts that power into thrust. In a turn to the right, the tail rotor sits in the main rotor’s downwash, so it sees faster, more energetic airflow. That increases its thrust per unit of power, letting you achieve the same yaw rate with less power. In a left turn, the tail rotor is in cleaner air with less downwash, so it’s less efficient and you need more power for the same yaw rate. Hence a pedal turn to the right requires less power than a pedal turn to the left.