As aircraft got quicker and more manoeuvrable, newer metrics were introduced. These were for example excess power, axial acceleration and pitch rate. As aircraft become even more agile, and current metrics become less telling, second order terms are beginning to be looked at. These are things like the rate of change of axial acceleration, rate of change of excess power, and also things like roll and engine spool lags that only have small effect on slower aircraft, but which are becoming ever more important. It is important that existing metrics are not ignored, but that they become supplemented by new ones.
Modern tactics mean that manoeuvres tend to be very quick and short lasting.
This means that transient response has become more important to performance metrics. In fact, this is the area where current metrics fall down. They are based on steady state models and so do not show the effect of transient motions. This project is aimed at finding metrics that will give an insight into the performance of advanced fighter aircraft using thrust vectoring. Along with this, the development of performance metrics describing advanced conventional fighters will come.