Which component restrains lead and lag movements in the main rotor system?

• A. Dampers
• B. Tail Rotor Head
• C. Swashplate
• D. Pitch Control Rods

Answer: (A)

Lead-lag motion is the back-and-forth movement of a rotor blade in the plane of rotation. If this movement isn’t restrained, it can build into vibrations and unstable oscillations as the blade twists and passes through the rotor plane.

Dampers in the main rotor head are specifically designed to limit that motion by providing resistance to motion about the lead-lag axis. They absorb energy from each oscillation, slow down the motion, and dampen vibrations, keeping the blades stable and tracking properly with less vibration.

The other components mentioned don’t perform this damping role: the tail rotor head handles anti-torque and yaw control, while the swashplate and pitch control rods deal with changing blade pitch, not restraining lead-lag motion.