THE DETERMINATION OF AIRCRAFT STABILITY COEFFICIENTS FROM FLIGHT-TEST DATA PART Ⅲ LATERAL INVESTIGATIONS

摘要

The lateral stability coefficients in the yawing and rolling moment equations were extracted from digitally simulated aircraft responses by the integral method of Shihbrot, the derivative method and a new statistical method. The effects on the lateral extraction accuracy of response data precision, the time increment between data points, and the length of the response data interval were studied. The influence of nonlinear inertial terms and dynamic pressure on the extracted results was evaluated. Nonlinear aerodynamic moments in the equations of motion were considered and extractions of the nonlinear variation of C1 with angle of attack and of C with both sideslip and angle of attack were obtained.