Sikorsky Aircraft Corporation

Krzysztof Kopanski

Justin J Thomas

Mark Winfield Scott

Frank M Caputo

Joshua A Breon

Benjamin Isabella

Jonathan K Wong

Daniel A Griffiths

Michael Skylar Lawson

A tail rotor blade for a helicopter includes a blade body defining a longitudinally extending spar cavity, a leading edge forward of the spar cavity, and a trailing edge aft of the spar cavity. Upper and lower airfoil surfaces extend from the leading edge to the trailing edge on opposite sides of the spar cavity. The upper and lower airfoil surfaces define between one another a constant airfoil segment and transition airfoil segments disposed longitudinally adjacent to the constant airfoil segment on inboard and outboard sides of the constant airfoil segment.

Helicopter tail rotor blades and blade assemblies

A blade includes a blade body having a surface and a hole extending through the surface of the blade body. The hole defines a hole axis and a plane perpendicular to the hole axis. The hole has an elongated hole perimeter within the plane. The hole perimeter includes a plurality of non-linear perimeter sections to minimize stress concentration around the elongated hole perimeter while maximizing the usable opening area. A rotor system includes a rotor hub and a blade as recited above. The blade extends radially outward from the rotor hub. The blade defines a root end proximate to the rotor hub, a tip end opposite the root end.

Stress reducing holes

An aircraft rotor blade includes a surface of the rotor blade, at least one main hole that extends through the surface and has a width and a length, and at least one leader hole that extends through the surface and has a length that is less than the length of the main hole and arranged spaced from and adjacent the main hole. The leader hole gradually increases in width from a first end of the leader hole opposite the main hole to an opposed second end of the leader hole proximate the main hole to operatively gradually distribute stress in the leader and main holes and rotor blade and reduce an amount of the stress exerted therein.

Aircraft rotor blade with reduced stress

A main rotor trim tab retention system includes, a blade housing having flanges separated by a cavity defined between the flanges, and a trim tab assembly. The trim tab assembly includes, a trim tab having an aerodynamic surface, at least one arm extending from the trim tab positionable within the cavity while the trim tab extends outward from the cavity, and a spherical bearing connecting the trim tab and the at least one arm, the spherical bearing having a first axis which is substantially perpendicular to the aerodynamic surface of the trim tab. The at least one arm is pivotable about the spherical bearing about a second axis substantially perpendicular to the first axis to rotate the trim tab relative to the blade housing.

Main rotor trim tab retention system, an aircraft employing same and a method of replacing a trim tab assembly from blade housing

A rotor system is provided including a rotor hub configured to rotate about an axis and a plurality of rotor blade assemblies mounted to the rotor hub and configured to rotate within a plane about the axis. A vibration reducing system is operably coupled to the rotor hub. The vibration reducing system is arranged at a position offset from a center of rotation of the rotor hub.

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Trumbull, CT, United States of America

Krzysztof Kopanski