The Boeing Company

Spirit Aerosystems, Inc.

Judith Marie Gallman

Joe Everet Sternberger

Robert K Kunze, Jr

Mary K Drouin

An inlet for an aircraft engine nacelle having an acoustic barrel panel, a septum buried or sandwiched within the acoustic barrel panel, and a perforated face sheet. The inlet may be located forward of an engine and/or an engine fan housed within the aircraft engine nacelle. Both the septum and the perforated face sheet may have perforations or holes therein of varying sizes and varying distances apart from each other. The smaller the area of the perforations or holes and the further apart they are from each other, the higher the impedance of a given area of the septum or the perforated face sheet. The impedance of the septum and/or the perforated face sheet may progressively increase in a direction away from the engine fan.

Engine inlet varying impedance acoustic liner section

A portable acoustic impedance data acquisition and processing system is provided for use with a test object. The system includes a dynamic signal analyzer, a test head, a removable microphone holder, a cylindrical endcap fitting, an amplifier, and one or more power supply sources. The test head includes a compression driver and a cylindrical waveguide tube. The waveguide tube has a first end connected to the compression driver and a second end that is open. The removable microphone holder is attachable to the waveguide tube near its second end and a number of microphones are insertable into the microphone holder. During use, the dynamic signal analyzer provides audio output test signals that are amplified by the amplifier and fed to the compression driver for use as the acoustic test signal. The microphones provide measured signals to the dynamic signal analyzer which analyzes them and makes the results available to the operator. The endcap fitting is for use in calibrating and adjusting microphone measurements prior to actual testing. The fitting includes a first end adapted to engage the second end of the waveguide tube and a second end having a mounting disc into which the microphones may be held longitudinally.

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Wichita, KS, United States of America

Judith Marie Gallman