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Klein, Vladislav

Publications and source records attributed to Klein, Vladislav.

43 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Aerodynamic parameters of an advanced fighter aircraft estimated from flight data. Preliminary results

Preliminary estimates of aerodynamic parameters of an advanced fighter aircraft were obtained from flight data of different values of the angle of attack from 8 to 54 deg. The data were analyzed by a stepwise regression with the ordinary least squares technique. The estimated stability and control derivatives are plotted against the angle of attack and compared with wind tunnel measurement and previous flight results. Also included is the data compatibility check of measured data. The effect of various input forms on the estimates is demonstrated in two examples using simulated data.

Klein, Vladislav↗
NASA NTRS1989

Estimation of aircraft aerodynamic parameters from flight data

Several ways for obtaining aerodynamic parameters of an aircraft from flight data are presented. A brief description of data analysis from steady measurements is given, and a concept of system identification is introduced. This is followed by a mathematical model of an aircraft with aerodynamic forces and moments approximated either by polynomials or splines and a detailed treatment of two often-used techniques for parameter estimation. Because of renewed interest in frequency-domain analysis, one section of the paper is devoted to this problem. The methods are demonstrated in several examples using real flight data.

Klein, Vladislav↗
NASA NTRS1988

Two biased estimation techniques in linear regression: Application to aircraft

Several ways for detection and assessment of collinearity in measured data are discussed. Because data collinearity usually results in poor least squares estimates, two estimation techniques which can limit a damaging effect of collinearity are presented. These two techniques, the principal components regression and mixed estimation, belong to a class of biased estimation techniques. Detection and assessment of data collinearity and the two biased estimation techniques are demonstrated in two examples using flight test data from longitudinal maneuvers of an experimental aircraft. The eigensystem analysis and parameter variance decomposition appeared to be a promising tool for collinearity evaluation. The biased estimators had far better accuracy than the results from the ordinary least squares technique.

Klein, Vladislav↗
NASA NTRS1987

Validation of aerodynamic parameters at high angles of attack for RAE high incidence research models

Two series of free-flight tests have been conducted for combat aircraft configuration research models in order to investigate flight behavior near departure conditions as well as to obtain response data from which aerodynamic characteristics can be derived. The structure of the mathematical model and values for the mathematical derivatives have been obtained through an analysis of the first series, using stepwise regression. The results thus obtained are the bases of the design of active control laws. Flight test results for a novel configuration are compared with predicted responses.

Ross, A. Jean↗
NASA NTRS1987

Partitioning of flight data for aerodynamic modeling of aircraft at high angles of attack

It is sometimes necessary to determine aerodynamic model structure and estimate associated stability and control derivatives for airplanes from flight data that cover a large range of angle of attack or sideslip. One method of dealing with that problem is through data partitioning. The main purpose of this paper is to provide an explanation of a data partitioning procedure and its application and to discuss both the power and limitations of that procedure for the analysis of large maneuvers of aircraft. The partitioning methodology is shown to provide estimates for coefficients of those regressors that are well excited in the aircraft motion. In particular, primary lateral stability and damping derivatives are identified throughout the maneuver ranges.

Batterson, James G.↗