The definition of short-period flying qualities characteristics via equivalent systems

Abstract

The high-order transfer functions representing the longitudinal dynamics of augmented aircraft were matched in the frequency domain with firstover second-order short-period models. Matching of the pitch rate to pilot input transfer function is shown to yield excellent time history matches. However, the resulting numerator term, La, takes on very large unrealistic values. The effect of simultaneously matching pitch rate and normal acceleration to restrict the variation of La is demonstrated. A control anticipation parameter is recommended to provide correlation between the highand low-order system descriptions and the specification requirements.