A study of aircraft agility

Abstract

Two mathematical models are applied to the study of a flight performance problem for an air-superiority fighter aircraft. The first model considers the body axes angular rates as control variables and is accordingly referred to as the body rate model. The second model is a rigid body model featuring rotational dynamics governed by the primary control surface deflections. The body rate model is intermediate between a point-mass model and rigid body model and accordingly, useful for preliminary design applications. Comparisons between the two models are made to determine the utility of each when applied to a particular flight problem.

The integral flight performance problem combines notions of roll and pitch agility in a roll reversal maneuver. The flight problem is formulated as an optimal control problem for each of the models. Parameter variations in the initial flight condition specified by the load factor, and in the available roll and pitch control powers were studied and used to compare the models. The results indicate deficiencies in the body rate model as an accurate predictor of agile aircraft characteristics.