초록 ▼

An active control device for reducing blade-vortex interactions (BVI) noise generated by a rotorcraft, such as a helicopter, comprises a trailing edge flap located near the tip of each of the rotorcraft's rotor blades. The flap may be actuated in any conventional way, and is scheduled to be actuated

An active control device for reducing blade-vortex interactions (BVI) noise generated by a rotorcraft, such as a helicopter, comprises a trailing edge flap located near the tip of each of the rotorcraft's rotor blades. The flap may be actuated in any conventional way, and is scheduled to be actuated to a deflected position during rotation of the rotor blade through predetermined regions of the rotor azimuth, and is further scheduled to be actuated to a retracted position through the remaining regions of the rotor azimuth. Through the careful azimuth-dependent deployment and retraction of the flap over the rotor disk, blade tip vortices which are the primary source for BVI noise are (a) made weaker and (b) pushed farther away from the rotor disk (that is, larger blade-vortex separation distances are achieved).

대표청구항 ▼

[ What is claimed is:] [1.] An active control device for reducing blade vortex-interaction (BVI) noise generated by a rotorcraft having a rotor blade including a tip end, a root end, a leading edge, and a trailing edge, said rotor blade being attached at said root end to a rotor hub on said rotorcra

[ What is claimed is:] [1.] An active control device for reducing blade vortex-interaction (BVI) noise generated by a rotorcraft having a rotor blade including a tip end, a root end, a leading edge, and a trailing edge, said rotor blade being attached at said root end to a rotor hub on said rotorcraft and extending radially outwardly therefrom, having a radius R and a chord C, such that when said rotor hub is rotatably driven, said rotor blade rotates about said hub through a 360 degree azimuth, said active control device comprising:a movable flap pivotally attached to said rotor blade trailing edge by a hinge oriented generally radially along said rotor blade, at least a portion of said flap being positioned near said rotor blade tip, in about the outboard 25% of the rotor blade radial length;an actuator for deflecting and retracting the flap about said hinge;wherein said flap is adapted to be actuated to a deflected position during rotation of said rotor blade through predetermined regions of said rotor azimuth, and is further adapted to be actuated to a retracted position through the remaining regions of said rotor azimuth, thereby functioning to reduce BVI noise during operation of said rotorcraft.