US Patent 11162472 Rotor blade

A lift type rotor blade which has a chord length gradually increased from a blade root to a maximum chord length portion being a base portion of a blade end portion, includes a leading edge, a front surface and an inclined portion formed on the blade end portion. The leading edge has a maximum thickness that is the maximum at the blade root and is gradually and continuously decreased from the blade root to a tip portion via the maximum chord length portion in a side view. The front surface is gradually inclined in a direction of a back surface from the blade root to the maximum chord length portion such that an interval between the front and back surfaces is continuously decreased. The inclined portion is inclined in a front surface direction from the maximum chord length portion.