초록 ▼

A tiltrotor aircraft having a fixed wing and tilting rotors has a rotor blade with a shaped tip portion that provides improved hover performance. The shaped tip portion preferably has a terminal anhedral of at least 20° with respect to its stacking line, and the blade has an overall twist from root

A tiltrotor aircraft having a fixed wing and tilting rotors has a rotor blade with a shaped tip portion that provides improved hover performance. The shaped tip portion preferably has a terminal anhedral of at least 20° with respect to its stacking line, and the blade has an overall twist from root to tip of at least 20°, and a thickness ratio between 19% and 30% at a radial station of 10%. These features advantageously conspire to provide a hover figure of merit of at least 0.84 and a cruise propulsive efficiency of at least 0.85. A controller preferably limits the rotor speed in sustained airplane-mode forward flight cruise of at most 40% of a hover maximum rotor speed, and alternatively or additionally limits a rotor edgewise advance ratio to at most 0.20.

대표청구항 ▼

What is claimed is: 1. A rotorcraft comprising:a fixed wing of sufficient size to allow wing-borne flight;the wing carrying a first rotor on a first side of the rotorcraft and a second rotor on an opposite side of the aircraft;the rotors configured to tilt from a predominately horizontal position to

What is claimed is: 1. A rotorcraft comprising:a fixed wing of sufficient size to allow wing-borne flight;the wing carrying a first rotor on a first side of the rotorcraft and a second rotor on an opposite side of the aircraft;the rotors configured to tilt from a predominately horizontal position to a predominantly vertical position; andthe first rotor with a first blade having a stacking line, with the first blade having a shaped tip portion with a terminal anhedral of at least 33° and a terminal sweep of at least 20° with respect to the stacking line, wherein the rotor is oriented for edgewise flow with an advance ratio of at least 0.05 during at least a portion of a flight.