What does the intermediate gearbox do?

The intermediate gearbox plays a crucial role in the operation of rotorcraft by being responsible for reducing the rotational speed (RPM) of the power generated by the engine and altering the angle of drive to the tail gearbox. This function is essential because the main rotor operates at a different speed and orientation compared to the tail rotor. By managing the RPM and the direction of the power transmission, the intermediate gearbox ensures that both rotors operate efficiently and effectively, contributing to the overall stability and control of the aircraft.

This mechanism is vital for maintaining the balance and directional control provided by the tail rotor, which counters the torque created by the main rotor. It allows the tail rotor to operate at the appropriate speed and in the correct alignment, supporting effective flight maneuvers and aiding in directional stability. Other options such as transmitting power directly to the main rotor, controlling electrical systems, or supporting auxiliary power unit functionality are functions associated with other components of the aircraft, highlighting the specific and critical role of the intermediate gearbox in rotorcraft design and operation.