In principle, a fighter aircraft without a vertical tail will possess improved stealth characteristics. However, it remains to be seen whether a tailless aircraft can be built that will be capable of true fighter performance. Lateral stability, in particular, must be provided artificially, especially during aggressive maneuvering.

It is thus important to evaluate the performance of the overall flight control system of tailless fighters over a class of aggressive maneuvers representative of fighter combat. Although a suite of maneuvers could be supplied by recording the actions of a pilot in simulated flight, the level of effort required to equip a pilot-in-the-loop simulator with appropriate dynamics is difficult to justify in the early stages of flight control systems development and evaluation.

We present a strategy for obtaining aggressive flight maneuvers similar to what might be produced by a pilot. We use a highly simplified aircraft model that can account for the lift/drag and thrust characteristics of an aircraft under consideration. When thrust is considered an input, this model is differentially flat (and dynamically feedback linearizable) so that the system can be made to follow any reasonable trajectory. Most trajectories will require significant movement of the throttle. Except in close formation, a pilot does not tend to make rapid throttle adjustments. Indeed, many maneuvers are accomplished using a fixed throttle position. The objective is to fly a desired path rather than a (time indexed) trajectory.

Although the aircraft model with throttle fixed (thrust predetermined) is no longer differentially flat, we show that the system can still be made to follow any reasonable path. Roughly speaking, an appropriate derivative of the path parametrization variable acts as the missing control allowing flatness-like results to be obtained.