Estimation of Aircraft Nonlinear Unsteady Parameters From Wind Tunnel Data PDF Download
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Author: Vladislav Klein
Publisher:
ISBN:
Category : Oscillations
Languages : en
Pages : 46
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Book Description
Author: Vladislav Klein
Publisher:
ISBN:
Category : Oscillations
Languages : en
Pages : 46
Get Book
Book Description
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722208226
Category :
Languages : en
Pages : 44
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Book Description
Aerodynamic equations were formulated for an aircraft in one-degree-of-freedom large amplitude motion about each of its body axes. The model formulation based on indicial functions separated the resulting aerodynamic forces and moments into static terms, purely rotary terms and unsteady terms. Model identification from experimental data combined stepwise regression and maximum likelihood estimation in a two-stage optimization algorithm that can identify the unsteady term and rotary term if necessary. The identification scheme was applied to oscillatory data in two examples. The model identified from experimental data fit the data well, however, some parameters were estimated with limited accuracy. The resulting model was a good predictor for oscillatory and ramp input data. Klein, Vladislav and Murphy, Patrick C. Langley Research Center RTOP 522-33-11-05...
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722379902
Category :
Languages : en
Pages : 44
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Book Description
Aerodynamic equations with unsteady effects were formulated for an aircraft in one-degree-of-freedom, small-amplitude, harmonic motion. These equations were used as a model for aerodynamic parameter estimation from wind tunnel oscillatory data. The estimation algorithm was based on nonlinear least squares and was applied in three examples to the oscillatory data in pitch and roll of 70 deg triangular wing and an X-31 model, and in-sideslip oscillatory data of the High Incidence Research Model 2 (HIRM 2). All three examples indicated that a model using a simple indicial function can explain unsteady effects observed in measured data. The accuracy of the estimated parameters and model verification were strongly influenced by the number of data points with respect to the number of unknown parameters. Klein, Vladislav and Noderer, Keith D. Langley Research Center RTOP 505-64-52-01...
Author:
Publisher: DIANE Publishing
ISBN: 1428996788
Category :
Languages : en
Pages : 29
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Book Description
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722380052
Category :
Languages : en
Pages : 48
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Book Description
A nonlinear least squares algorithm for aircraft parameter estimation from flight data was developed. The postulated model for the analysis represented longitudinal, short period motion of an aircraft. The corresponding aerodynamic model equations included indicial functions (unsteady terms) and conventional stability and control derivatives. The indicial functions were modeled as simple exponential functions. The estimation procedure was applied in five examples. Four of the examples used simulated and flight data from small amplitude maneuvers to the F-18 HARV and X-31A aircraft. In the fifth example a rapid, large amplitude maneuver of the X-31 drop model was analyzed. From data analysis of small amplitude maneuvers ft was found that the model with conventional stability and control derivatives was adequate. Also, parameter estimation from a rapid, large amplitude maneuver did not reveal any noticeable presence of unsteady aerodynamics. Klein, Vladislav and Noderer, Keith D. Langley Research Center RTOP 505-64-52-01...
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1152
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Book Description
Author: Vladislav Klein
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 32
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Author: M. J. Queijo
Publisher:
ISBN:
Category :
Languages : en
Pages : 60
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Book Description
Author: J. A. Burns
Publisher:
ISBN:
Category : Aerofoils
Languages : en
Pages : 88
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Book Description
This report is concerned with the development of a general mathematical model for the motion of a two-dimensional airfoil in unsteady aerodynamics and with the study of numerical schemes for estimating parameters in this model. The equations of motion are a set of coupled ordinary and functional differential equations. Approximating Wagner functions are used to construct state space models that retain the hereditary nature of unsteady fluid flow. The results of some simple numerical experiments are presented including a preliminary analysis of wind-tunnel data. (Author).
Author:
Publisher:
ISBN:
Category : Oscillations
Languages : en
Pages : 70
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Book Description
