SIFT Army Aviation Information Practice Test

What is the purpose of the tail rotor on a helicopter?

1. To create kinetic energy that is transformed into potential energy as the helicopter climbs

2. To produce rotational momentum that is used by the transmission to drive a generator

3. To produce an anti-torque force acting perpendicular to the helicopter's longitudinal axis

4. All the above

The correct answer is: To produce an anti-torque force acting perpendicular to the helicopter's longitudinal axis

The tail rotor on a helicopter primarily serves the purpose of producing an anti-torque force that counteracts the rotational torque generated by the main rotor. As the main rotor spins, it creates a torque effect that tends to rotate the helicopter's body in the opposite direction. If unopposed, this torque would cause the helicopter to spin uncontrollably. The tail rotor, positioned at the rear of the helicopter, generates thrust in a direction that counterbalances this torque, thus maintaining the helicopter's stability and allowing the pilot to control its yaw. In contrast, the other options do not accurately represent the main function of the tail rotor. The creation of kinetic energy to potential energy during climbing relates more to the main rotor's function, not the tail rotor. Similarly, the concept of producing rotational momentum for driving a generator is unrelated to the tail rotor's primary role. Therefore, the correct answer highlights the essential function of the tail rotor in providing stability and control by countering torque.