Estimation of Rolling Effectiveness and Control Reversal for Aeroelasticity Effects

Control effectiveness is the potential of a control surface to change the aircraft attitude in pitch, roll or yaw. This effectiveness can be considerably reduced due to the twist of an elastic airfoil. The reduction due to flexibility of aerostructure subsequently results in complete loss of efficacy of a control surface, resulting in control reversal. This study investigates the roll effectiveness and reversal of a standard wing. Analytical model of a fighter aircraft wing is used for static aeroelasticity analysis. The finite element analysis is carried out to investigate structural deformations that are caused by steady aerodynamic forces. Control surface effectiveness values were measured from the rolling moment stability derivatives. Reversal behavior for the selected geometric structure was studied and essential equations are developed. An algorithm is developed in NASTRAN and executed in FEMAP software for static aeroelasticity analysis of the model. Wing is considered to be flying in an incompressible air with nil Mach number and a specific value of dynamic pressure. Effects of different dynamic pressure values and variable size of control surface are examined. Results obtained through the software are tabulated and plotted to get a fair idea for roll behavior and reversal point of the control surface. Same was then compared with the theoretical results on the subject and are found in good agreement.