Measurements of Aerodynamic Stability Derivatives of an Airplane in Wind Tunnels

The two methods for determining the aerodynamic stability derivatives of an airplane in wind tunnels are investigated. The principles of measurements are as follows: 1. Method for determining the stability derivatives from frequency response characteristics of the dynamic system containing the model with application of the forced oscillation of constant amplitude 2. Method for determining the stability derivatives from the transient response data to the step control deflection input of the model The former is suitable for the low speed wind tunnel test, and the latter is for the high speed wind tunnel respectively. The theoretical calculation and the experimental results for these two methods are reported.