Sikorsky Aircraft Corporation

General Dynamics Advanced Information Systems, Inc.

General Dynamics Advanced Technology Systems, Inc.

Michael S Torok

Peter F Lorber

William Arthur Welsh

Robert C Moffitt

Brian Ernest Wake

Charles R Berezin

Geoffrey C R Davis

Andreas P F Bernhard

Antonios N Kotoulas

Tahany Ibrahim El-Wardany

George Gustave Zipfel, Jr

Gregory Weston Terpay

Ashish Bagai

Peter J Fitzpatrick

Ka-Shu Lee

William C Harris, Jr

William Edward Vanderbeck

Paul Darcy, Jr

A multi-element rotor blade includes an individually controllable main element and fixed aerodynamic surface in an aerodynamically efficient location relative to the main element. The main element is controlled to locate the fixed aerodynamic surface in a position to increase lift and/or reduce drag upon the main element at various azimuthal positions during rotation.

Active control of multi-element rotor blade airfoils

A method of predicting the cutting speed for machining of titanium alloy comprising the steps of obtaining a first transfer function for a tool system, obtaining a second transfer function for a workpiece system, selecting from the first transfer function a first flexible mode, selecting from the second transfer function a second flexible mode, defining a natural frequency of the first flexible mode and the second flexible mode, calculating a tooth passing frequency using the defined natural frequency, accepting the calculated tooth passing frequency if the calculated tooth passing frequency differs from a second harmonic of a combined system formed of the tool system and the workpiece system and from at least one natural frequency corresponding to the tool system and the workpiece system, calculating a stable spindle speed, defining a cut depth using the calculated spindle speed.

Process and methodology for selecting cutting parameters for titanium

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 .

Two neural networks are used to control adaptively a vibration and noise-producing plant. The first neural network, the emulator, models the complex, nonlinear output of the plant with respect to certain controls and stimuli applied to the plant. The second neural network, the controller, calculates a control signal which affects the vibration and noise producing characteristics of the plant. By using the emulator model to calculate the nonlinear plant gradient, the controller matrix coefficients can be adapted by backpropagation of the plant gradient to produce a control signal which results in the minimum vibration and noise possible, given the current operating characteristics of the plant.

Neural net controller for noise and vibration reduction

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.

Directional elastomeric coupler

A hub mounted actuation system for providing control of a portion of a rotor blade, such as a flap, on a rotorcraft. The rotor blade is attached to a rotor shaft that rotates with respect to an airframe. The hub mounted actuation system includes a stationary support mounted to the airframe and a rotary support attached to the rotor shaft for concomitant rotation therewith. At least one hub actuator rotates in combination with the rotor blade and includes a piston which is slidable within a housing. The piston and housing define a pressure chamber within the actuator which contains a fluid to be pressurized. A displacement control device is disposed between the stationary support and the rotary support for controlling movement of the piston within the housing. A linkage connects the hub actuator to the portion of the blade to be controlled. The linkage is adapted to displace the blade portion as a function of the movement of the piston within the housing.

Rotor hub mounted actuator for controlling a blade on a rotorcraft

Growing community of inventors

Hamden, CT, United States of America

Michael S Torok