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Extraction of aerodynamic parameters for aircraft at extreme flight conditionsThe maximum likelihood estimator was used to extract stability and control derivatives from flight data for many years. Most of the literature on aircraft estimation concentrates on new development and applications, assuming familiarity with basic concepts. The maximum likelihood estimator and the aircraft equations of motion that the estimator uses are discussed. The current strength and limitations associated with obtaining flight-determined aerodynamic coefficients in extreme flight conditions are assessed. The importance of the careful combining of wind tunnel results (or calculations) and flight results and the thorough evaluation of the mathematical model is emphasized. The basic concepts of minimization and estimation are examined for a simple computed aircraft example, and the cost functions that are to be minimized during estimation are defined and discussed. Graphic representations of the cost functions are given to help illustrate the minimization process. Finally, the basic concepts are generalized, and estimation of stability and control derivatives from flight data is discussed.
Document ID
19860017776
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Iliff, K. W.
(NASA Hugh L. Dryden Flight Research Center Edwards, CA, United States)
Date Acquired
August 12, 2013
Publication Date
November 1, 1985
Publication Information
Publication: AGARD Unsteady Aerodynamics-Fundamentals and Applications to Aircraft Dynamics
Subject Category
Aerodynamics
Accession Number
86N27248
Distribution Limits
Public
Copyright
Other
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