Patent ID: 8911209

Claim:
A helicopter rotor comprising: a blade; a rotor hub which supports said blade; and a lead-lag angle mechanism configured to change a lead-lag angle of said blade in synchronization with rotation of said rotor hub such that a lag angle is given to said blade on a first side of a helicopter movement direction, on which first side said blade is rotating in the movement direction, and a lead angle is given to said blade on a second side of the movement direction of said helicopter, on which second side said blade is rotating opposite to the movement direction, wherein: said blade comprises a spar having a spar tip-side portion and a spar hub-side portion hinged to each other by a lead-lag hinge; said lead-lag angle mechanism comprises a link mechanism that causes said spar tip-side portion to pivot about said lead-lag hinge with respect to said spar hub-side portion to give said blade the lag angle on the first side of the helicopter movement direction and the lead angle on the second side of the helicopter movement direction in synchronization with rotation of said rotor hub and in dependence upon a rotational position of said blade with respect to the helicopter movement direction; said blade includes a blade hub side portion positioned on a rotor hub side with respect to said lead-lag hinge; said spar hub side portion is arranged inside said blade hub side portion; said blade hub side portion includes a first rail; and said spar hub side portion includes a first roller which engage said first rail.