Pseudosteady state analysis of nonlinear aircraft maneuvers

Abstract

SUMMARYAn analytical method has been developed for studying the combined effects of rotational coupling and nonlinear aerodynamics on aircraft response for specified control inputs. The method involves the simultaneous solution of two nonlinear equations which are functions of angle of attack, roll rate, and control inputs. The method is applied to a number of maneuvers for a fightertype aircraft. Time history responses verified the usefulness of the analysis for predicting a variety of response characteristics caused by interacting nonlinear aerodynamic and inertial effects, including spin conditions.

Bifurcation analysis of inertia coupled roll manoeuvres of airplanes

“…The ®rst step of the EBA procedure provides a convenient way of ®nding a starting point satisfying the augmented set of equation (9) with the VVR constraint. The continuation algorithm is used to solve equation (4), while evaluating at each step the magnitude of V . The point at which …V †=…jVjj j † becomes 1 is noted and used as the starting point for the continuation of VVR solutions.…”

“…A jump in the roll rate was seen to occur at a critical aileron de¯ection that was associated with the existence of multiple PSS roll rate solutions and a folding of the PSS solutions. Young et al [4] extended this work by studying the PSS dynamics of an aircraft with a non-linear aerodynamic model. They observed that jump phenomenon in roll manoeuvres was mainly caused by the inertia coupling terms in the aircraft equations of motion, with the nonlinear aerodynamic terms playing an insigni®cant role.…”

Study of deep-stall characteristics and longitudinal special phenomena of T-tail aircraft

“…Quantitative results of global stability were presented, using numerical techniques based on parametric continuation [1]. Young, Scky and Johnson applied BACTM to study the steady states of the fifth order equations of motions which include an aerodynamic model that was a nonlinear function of the angle of attack [2]. The global stability of the results provides a qualitative understanding of the dynamics of the aircraft.…”

Application of dynamical systems theory to nonlinear aircraft dynamics

“…reference [13]. The model is symmetriC with respect to aileron deflection and all aerodynamic -coefficients are nonlinear functions of angle of attack for angles from -10 to +90 degrees.…”

“…Changes in the stability of the steady states along those curves signify critical control surface deflections which cause instabilities. The roll coupling problem was thoroughly analyz~ by calculating the steady states of an aircraft and their changes of stability 1n reference (5].…”