Question 3 (Total: 10 marks) a) b) i) ii) The longitudinal transfer function for the A4 Skyhawk Aircraft is: 0 (s) -8.096(s - 0.0006) (s+ 0.3591) n(s) (s² +0.014s + 0.0068)

(s² +1.009s +5.56) (1) Appraise all the longitudinal modes of the aircraft, by computing the damping ratio and frequencies. Based on result obtained in part (i), differentiate and discuss the key differences between the modes. iii) Use time history plots of key flight parameters (u, a, q.), to appraise the physical flight behavior of these two modes = To improve the characteristic of these mode, a simple feedback system is used. The closed loop transfer function is as follow: PARA 0 (s) 8,(s) 46 The corresponding root locus plot is shown in Figure 3. 46 K(s - 0.0006)(s+ 0.3591) (s² +0.014s +0.0068) (s² +1.009s +5.56) L 48-174 45 4 -10.4 K-358 -02 36 Branch A: Branch B: 12 Branch (ii) As K increases, describe the changes in (iii) As K increases, describe the changes in 0 L *X=209 Name the mode that corresponding to branch A and B in the plot: mode mode K-350 X=104 and for mode A and for mode B