Assertion: helicopter's blade | /r/CreatedBy | flapping movement
Facets:
Source sentences:
text: Other forces acting upon helicopters include coning, the upward bending effect on blades caused by centrifugal force; Coriolis effect, the acceleration or deceleration of the blades caused by the flapping movement bringing them closer to (acceleration) or farther away from (deceleration) the axis of rotation; and drift, the tendency of the tail rotor thrust to move the helicopter in hover.