Experiment on Quasi-Tailless Flight of an X-31A Airplane

An experiment consisting of flight tests on the X-31A airplane (see figure) has demonstrated the ability to use thrust vectoring to replace the functions of stabilization and turn coordination usually required of a rudder and vertical tail. Comments by the pilot indicated no difference in handling qualities for the majority of the tests flown. The experiment showed that the greatest demand was placed on the thrust-vectoring system at low thrust settings and high roll accelerations. It was demonstrated that a higher level of interaction between the engine and flight-control system will be needed for future reduced-tail or tailless aircraft with thrust-vector control. This experiment helped to introduce thrust vectoring as a new design dimension for future aircraft.