flapping hinge

flapping hinge

flapping hingeclick for a larger image
A hinge connecting a rotor blade to the hub and about which the blade rises and falls (i.e., flaps during its rotation, and thus permits equalization of lift—or rotor thrust) between the advancing-blade half and the retreating-blade half of the rotor disc. The axis of a flapping hinge is parallel to the rotor plane of rotation.