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Flight testing and frequency domain analysis for rotorcraft handling qualities characteristicsA demonstration of frequency domain flight testing techniques and analyses was performed on a U.S. Army OH-58D helicopter in support of the OH-58D Airworthiness and Flight Characteristics Evaluation and the Army's development and ongoing review of Aeronautical Design Standard 33C, Handling Qualities Requirements for Military Rotorcraft. Hover and forward flight (60 knots) tests were conducted in 1 flight hour by Army experimental test pilots. Further processing of the hover data generated a complete database of velocity, angular rate, and acceleration frequency responses to control inputs. A joint effort was then undertaken by the Airworthiness Qualification Test Directorate (AQTD) and the U.S. Army Aeroflightdynamics Directorate (AFDD) to derive handling qualities information from the frequency response database. A significant amount of information could be extracted from the frequency domain database using a variety of approaches. This report documents numerous results that have been obtained from the simple frequency domain tests; in many areas, these results provide more insight into the aircraft dynamics that affect handling qualities than to traditional flight tests. The handling qualities results include ADS-33C bandwidth and phase delay calculations, vibration spectral determinations, transfer function models to examine single axis results, and a six degree of freedom fully coupled state space model. The ability of this model to accurately predict aircraft responses was verified using data from pulse inputs. This report also documents the frequency-sweep flight test technique and data analysis used to support the tests.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Ham, Johnnie A.
(Army Aviation Technical Test Center Fort Rucker, AL, United States)
Gardner, Charles K.
(Army Aviation Technical Test Center Fort Rucker, AL, United States)
Tischler, Mark B.
(Army Aviation Systems Command Moffett Field, CA., United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1993
Publication Information
Publication: NASA. Ames Research Center, Piloting Vertical Flight Aircraft: A Conference on Flying Qualities and Human Factors
Subject Category
Aircraft Stability And Control
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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