The blade of an helicopter rotor can have three hinges: pitch hing, flapping hinge and lead-led hinge.

Lead-lag (dragging): movement of a blade forward or aft in the plane rotation. Lead lag is facilitated by a lead-lag hinge in the rotor system or through rubber like bearings that allow individual rotor blades to move back and forth in their plane of rotation. This helps balance the blade system and reduces vibration. The drag brace or drag damper resists the movement of the blade around its lead-lag hinge on a semi-rigid rotor system.

In the same plane, we have also the hunting, defined as the tendency of a blade to oscillate ahead of or behind a position which would be determined by centrifugal force alone.

Why should the centrifugal force alone determine a movement aft and behind the plane of rotation?

The blade of an helicopter rotor can have three hinges: pitch hinge, flapping hinge and lead-lag hinge.

Lead-lag (dragging): movement of a blade forward or aft in the plane rotation. Lead lag is facilitated by a lead-lag hinge in the rotor system or through rubber like bearings that allow individual rotor blades to move back and forth in their plane of rotation. This helps balance the blade system and reduces vibration. The drag brace or drag damper resists the movement of the blade around its lead-lag hinge on a semi-rigid rotor system.

In the same plane, we have also the hunting, defined as the tendency of a blade to oscillate ahead of or behind a position which would be determined by centrifugal force alone.

Why should the centrifugal force alone determine a movement aft and behind the plane of rotation?