Which component is the Main Transmission?

• A. Main Transmission
• B. Main Rotor Head
• C. Rotor Brake System
• D. Main Rotor Blade

Answer: (A)

The key idea is how power moves from the engine to the rotor. The main transmission is the gear train that takes engine power, reduces its high speed to the rotor’s slower turning speed, and provides the necessary torque to drive the rotor system. It sits between the engine and the rotor head, and in many designs also drives other components. The main rotor head simply connects to the mast and allows the blades to pivot and spin, but it doesn’t transfer engine power by itself. The rotor brake system stops the rotor when parked, and the main rotor blades are the lifting surfaces, not the power-transmitting link. So the main transmission is the correct choice because it is the essential power transfer component from engine to rotor.