NATIONAL AERONAUTICS AND SPACE ADMINISTRATION EDWARDS AFB CA DRYDEN FLIGHT RESEARCH CENTER
The handling qualities of a typical hypersonic glider with basic aerodynamic controls were investigated with a flight simulator at Mach numbers of 0.26, 1.0, 3.5, 8, and 20 over an angle-of-attack range of 0 to 50 degrees. Inasmuch as flight conditions influencing the control of the glider can be expected to change relatively slowly, a five-degree-of-freedom mechanization was used. The pilots considered the control characteristics of the basic glider to be satisfactory only at lower Mach numbers and low angles of attack. Control coupling severely restricted the effectiveness of normal control techniques at high angles of attack, and extremely light damping was apparent over much of the flight envelope. The technique of using rudders to control bank angle was effective, especially at high angles of attack. Dampers greatly improved the vehicle handling qualities however, special control techniques were required, especially at high angles of attack. The adaptive control system with a special rudder interconnect and lateral-acceleration feedback provided acceptable control at all test conditions, including those at which the unaugmented glider was unstable.