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XV-15 Tiltrotor Low Noise Approach OperationsAcoustic data have been acquired for the XV- 15 tiltrotor aircraft performing approach operations for a variety of different approach profile configurations. This flight test program was conducted jointly by NASA, the U.S. Army, and Bell Helicopter Textron, Inc. (BHTI) in June 1997. The XV-15 was flown over a large area microphone array, which was deployed to directly measure the noise footprint produced during actual approach operations, The XV- 15 flew realistic approach profiles that culminated in IGE hover over a landing pad. Aircraft tracking and pilot guidance was provided by a Differential Global Positioning System (DGPS) and a flight director system developed at BHTT. Approach profile designs emphasized noise reduction while maintaining handling qualities sufficient for tiltrotor commercial passenger ride comfort and flight safety under Instrument Flight Rules (IFR) conditions. A discussion of the approach profile design philosophy is provided. Five different approach profiles are discussed in detail -- 3deg., 6 deg., and 9 deg. approaches, and two very different 3 deg. to 9 deg. segmented approaches. The approach profile characteristics are discussed in details, followed by the noise footprints and handling qualities. Sound exposure levels are also presented on an averaged basis and as a function of the sideline distance for a number of up-range distances from the landing point. A comparison of the noise contour areas is also provided. The results document the variation in tiltrotor noise due to changes in operating condition, and indicate the potential for significant noise reduction using the unique tiltrotor capability of nacelle tilt.
Document ID
19990069950
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
Authors
Conner, David
(Army Aviation and Missile Command Hampton, VA United States)
Marcolini, Michael A.
(NASA Langley Research Center Hampton, VA United States)
Decker, William A.
(NASA Ames Research Center Moffett Field, CA United States)
Cline, John H.
(Army Research Lab. Hampton, VA United States)
Edwards, Bryan D.
(Bell Helicopter Co. Fort Worth, TX United States)
Nicks, Colby O.
(Bell Helicopter Co. Fort Worth, TX United States)
Klein, Peter D.
(Bell Helicopter Co. Fort Worth, TX United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Acoustics
Distribution Limits
Public
Copyright
Other

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