A Method for Evaluating Aircraft Stability Parameters from Flight Test Data
Abstract
A least-squares method for evaluating aircraft stability derivaties and transfer function constants from flight test frequency response data is derived. The normalized least-squares equations for rotating vectors are derived by minimizing the sum of the squares of the residual vectors without regard to the phase angles of these residuals. This method was applied to longitudinal oscillation data obtained from flight tests of a USAF bomber-type B-25J aircraft. It is shown that a linear dependency in the longitudinal variables of motion must be resolved before any solution can be obtained. The assumption of a linear relationship between the stability derivatives for the forces or moments resulting from the rate of change of the angle of attack and the pitching velocity eliminated this dependency and gave acceptable results. The lift caused by pitching velocity must be included in order to obtain a reasonable value for the lift resulting from elevator deflection.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1952
- Accession Number
- ADA075866
Entities
People
- Lloyd E. Schumacher
Organizations
- Wright Laboratory