Hypersonic simulator experiments for long-term dynamics flying qualities

Unique long-term dynamics charactersitics of hypersonic flight and related flying qualities issues are considered. Aperiodic instability of the phugoid is of primary concern and it is shown how its stability characteristics can be independently changed. Various levels of aperiodic instability are investigated in simulator experiments which were subject to different tasks for the pilot at a Mach 10 flight condition. An evaluation is presented based on Cooper Harper ratings. In addition, the paper also reports on flight test activities with a SR-71 aircraft operated as a test vehicle.