Sikorsky Aircraft Corporation

Geoffrey C R Davis

William Arthur Welsh

Brian Ernest Wake

Robert C Moffitt

Peter F Lorber

Michael S Torok

Andreas P F Bernhard

A multi-element rotor blade includes a main element and an active slat movable relative to the main element. The slat rotates and translates relative to the main element from a base position. The base position provides a compromise between minimum coefficient of drag C and maximum coefficient of lift C . In the advancing blade, since the airspeed thereof is significantly greater than the retreating blade, the slat is positively rotated from the base position to minimizes drag at low angles of attack. In the retreating blade, since the airspeed thereof is significantly lower than the advancing blade, the slat is negatively rotated and translated to maximize the coefficient of lift C .

Active control of multi-element rotor blade airfoils

A method for producing a composite component having a variable thickness includes placing a caul member over a plurality of laid-up prepreg plies supported by a mold. The mold includes a cavity for receiving the lay-up that is defined by a bottom surface, a plurality of walls extending upwardly from the bottom surface, and an open upper face surrounded by a mold edge. A support flange extends inwardly toward the center of the cavity from each of the walls at a predetermined distance from the bottom surface. The caul is made from an anisotropic material so that the caul is basically rigid about lateral axis and flexible about a longitudinal axis. During an autoclave curing process, the caul applies pressure along the length of the lay-up to draw the caul into engagement with the support flange, which serves as a stop to prevent further movement of the caul.

Method for controlling thickness during lay-up and fabrication of composite components

An elastomeric coupler assembly having a helical elastomeric bearing movably supports an active slat relative to a main element. An inner elastomeric coupler assembly and an outer elastomeric coupler assembly support the slat therebetween. Centrifugal force operates to drive the slat to a first position and an actuator rod operates in tension to pull upon the inner elastomeric coupler assembly to drive the slat in opposition to the centrifugal force to a second position. The helical elastomeric bearing is layered such that it defines a section of a circular helix. The circular helix provides a coupling, which converts a linear input parallel to a virtual hinge axis into a rotary output to pitch the slat. In operation, centrifugal force operates to slide the slat outboard toward the blade tip such that the attached slat moves elastomerically along the helical arc of the helical elastomeric bearing to rotate the slat nose down. To retract the slat, the actuator operates to place the actuator rod under tension to pull upon the active member and retract the slat in opposition to centrifugal force.

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Madison, CT, United States of America

Geoffrey C R Davis