Which component provides RPM reduction for the tail rotor?

• A. Main gearbox/Main Transmission
• B. Free-wheeling unit
• C. Tail gearbox
• D. Accessory Gearboxes/Drives

Answer: (C)

The idea being tested is how the tail rotor gets the right speed. The tail gearbox is the component that reduces RPM for the tail rotor. Power from the engine goes through the main gearbox to drive the main rotor, and a separate drive shaft runs to the tail rotor where the tail gearbox lowers the speed to a suitable, controllable rate for anti-torque and yaw control. Without this reduction, the tail rotor would overspeed and lose efficiency.

Other parts have different roles: the main gearbox handles the main rotor’s reduction, the free-wheeling unit allows the rotor to freewheel in certain conditions (not for tail rotor speed), and accessory gearboxes/drives supply power to non-flight systems like generators and pumps.