22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-4.10.4

PATH-ATTITUDE INCONSONANCE IN HIGH SPEED FLIGHT AND RELATED PATH CONTROL ISSUES

R. Stich (1), G. Sachs (1), T.H. Cox (2)
(1) Technische Universität München, Munich, Germany; (2) NASA Dryden Flight Research Center, Edwards AFB, USA

Keywords: hypersonic flight, longitudinal dynamics, path-attitude lag, handling qualities, simulator experiments

This paper presents results of a joint research effort of NASA Dryden Flight Research Center and the Institute of Flight Mechanics and Flight Control of Technische Universität München on longitudinal flight dynamics at hypersonic speeds. At high speeds a large time lag between pitch attitude and flight path angle exists. The mechanisms which cause this path-attitude decoupling are described. It will be shown further that an limiting effect exists. An “aggressive stick” piloting technique to avoid the shortcomings of the path-attitude lag is described. This type of control is also effective to stabilize phugoid. The simulation facility of Dryden Flight Research Center which was used in the evaluation is described. Simulation results concerning the effect of path-attitude lag on “aggressive stick” technique, of time delay and scaling of vertical speed information are presented. Furthermore results of flight tests with SR-71 and Tu-144 at high supersonic speeds for similar topics are presented.

view full paper