Patent ID: 8800261

Claim:
A method of reducing a total effective perceived noise level of a gas turbine engine with a variable area fan nozzle in communication with a fan bypass flow path, the variable area fan nozzle having a first fan nacelle section and a second fan nacelle section, the second fan nacelle section axially movable relative the first fan nacelle section to define an auxiliary port to vary a fan nozzle exit area and adjust a fan bypass airflow comprising: defining an airfoil leading edge region of the second fan nacelle section by an elliptical contour which defines a baseline configuration with a radius less than 0.05δ where δ represents an upstream boundary layer thickness; increasing the semi-minor axis relative to the baseline configuration; and rotating the elliptical contour to align tangentially to a suction surface of the airfoil leading edge region to increase an airfoil leading edge radius relative to a baseline configuration to reduce boundary layer turbulence ingestion leading edge noise.