What is the primary purpose of the tail rotor?

• A. Control yaw
• B. Produce extra lift when lifting heavy external loads
• C. Drive the main rotor during autorotations
• D. Take direct inputs from the collective and translate those into tail rotor inputs

Answer: (A)

The primary purpose of the tail rotor is to control yaw, which is the rotational movement of the helicopter around its vertical axis. In a helicopter, the main rotor generates lift and thrust, but it also creates a torque effect due to its rotation. This torque causes the helicopter's fuselage to spin in the opposite direction of the main rotor's rotation. To counteract this unwanted yawing motion, the tail rotor provides a horizontal thrust that balances the torque produced by the main rotor. By adjusting the pitch of the tail rotor blades, the pilot can vary the amount of thrust produced, allowing for precise control of the helicopter’s heading. This is critical for maintaining stability and for conducting various maneuvers during flight.

The other options relate to functions that are not the primary role of the tail rotor. While producing extra lift for lifting heavy loads is important, this is primarily a function of the main rotor. Driving the main rotor during autorotations pertains to a specific flight scenario and does not reflect the primary role of the tail rotor. Additionally, translating collective inputs into tail rotor inputs is not the core function of the tail rotor itself; rather, it describes a feature of the helicopter’s control system that integrates multiple controls for flight dynamics.