The Boeing Company

Michael A McVeigh

Thomas A Zientek

Richard Bussom

Robert P Narducci

John Y Liu

Robert F Maciolek

Robert J Mayer

Embodiments of systems and methods for enhancing the performance of rotary wing aircraft through reduced torque, noise and vibration are disclosed. In one embodiment, a method includes configuring the rotorcraft in a selected flight condition, communicating input signals to a control system operable to position sails coupled to tips of blades of a rotor assembly, processing the input signals according to a constraint condition to generate sail positional information, and transferring the sail positional information to the sail. Alternately, input signals may be communicated to a control system operable to position a plurality of sails, each sail having an aerodynamic shape and positioned proximate to a tip portion of the rotor blade. The input signals may be configured to rotate each sail about a longitudinal axis into a corresponding pitch angle independently of the other sails.

System and method for improved rotor tip performance

An airborne mobile platform generally includes a plurality of rotating rotor blades operating in an airflow that forms a boundary layer on each of the rotor blades. At least one of the rotor blades includes a section that encounters the airflow that includes an unsteady subsonic airflow having at least a varying angle of attack. At least one of the rotor blades also includes one or more vortex generators on the at least one of the rotor blades that generate a vortex that interacts with the boundary layer to at least delay an onset of separation of the boundary layer, to increase a value of an unsteady maximum lift coefficient and to reduce a value of an unsteady pitching moment coefficient for the section.

Vortex generators on rotor blades to delay an onset of large oscillatory pitching moments and increase maximum lift

The present invention discloses systems and methods for the performance enhancement of rotary wing aircraft through reduced torque, noise and vibration. In one embodiment, a system includes a sail having an aerodynamic shape positioned proximate to a tip of the rotor blade. An actuator may be configured to rotate the sail relative to the blade tip. a A control system receives information from a rotorcraft system and commands the actuator to rotate the sail to a predetermined favorable rotor blade operating condition. In another embodiment, a method includes configuring the rotorcraft in a selected flight condition, communicating input signals to a control system operable to position sails coupled to tips of blades of a rotor assembly, processing the input signals according to a constraint condition to generate sail positional information, and transferring the sail positional information to the sail.

A tiltrotor aircraft includes a spanwise-flow redirector having a pair of flow-redirection panels respectively mounted on the aircraft's mid-fuselage area for rotation about a panel pivot axis between a stowed position and a deployed position. In the stowed position, each panel is substantially flush with an adjacent surface of the mid-fuselage area. In the deployed position, each panel is raised into the path of one of the inbound spanwise flows generated by the aircraft's rotors during hover operation, whereupon each panel redirects the respective one of the inbound spanwise flows either forward or aft of the other inbound spanwise flow. In this manner, the deployed panels prevent stagnation of the inbound spanwise flow atop the mid-fuselage area while further serving to minimize re-ingestion of merged spanwise flow into the rotors, resulting in decreased airframe download forces, increased rotor thrust, and reduced noise levels during hover operation.

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Media, PA, United States of America

Michael A McVeigh