Spring 2003 1661AC24 Longitudinal Actuators Primary actuators in longitudinal direction are the elevators and the thrust Clearly the thrusters elevators play a key role in defining the stead state/equilibrium fight condition Now interested in determining how they also influence the aircraft mo- tion about this equilibrium condition deflect elevator u(t), w(t), q(t), δ.(+) Rudde Recall that we defined AXc as the perturbation in the total force in the X direction as a result of the actuator commands Force change due to an actuator deflection from trim Expand these aerodynamic terms using the same perturbation approach △Xc=X60e+X6, de is the deflection of the elevator from trim(down positive) Sp change in thrust Xs and Xs, are the control stability derivativesSpring 2003 16.61 AC 2–4 Longitudinal Actuators • Primary actuators in longitudinal direction are the elevators and the thrust. – Clearly the thrusters/elevators play a key role in defining the steady￾state/equilibrium flight condition – Now interested in determining how they also influence the aircraft mo￾tion about this equilibrium condition deflect elevator → u(t), w(t), q(t),... • Recall that we defined ∆Xc as the perturbation in the total force in the X direction as a result of the actuator commands – Force change due to an actuator deflection from trim • Expand these aerodynamic terms using the same perturbation approach ∆Xc = Xδe δe + Xδp δp – δe is the deflection of the elevator from trim (down positive) – δp change in thrust – Xδe and Xδp are the control stability derivatives