Question 1 (Total: 15 marks) a) b) i) ii) iii) Sketch a typical Cm - a plot and discuss : the condition for trim the requirement for static stability, and the

concept of stability margin The pitching moment coefficient vs Lift Coefficient plot (evaluated at a CG position of h = 0.25) for a jet liner is shown below in Figure 1(a) Pitching Moment Coefficient CM 0.25 0.2 0.15 0.1 0.05- 30.2 0.05 -0.1 -0.15 -0.2 0 0,2 0:4 CM VS CL 06 0.8 Lift Coefficient CL Figure 1(a): CM vs C₁ The aircraft and the level flight parameters are as follow: mass = 70,000 kg S = 185.8 m² CG @ 0.25 12 Alt = 10,000 m V = 237.4 m/s (i) Appraise the Stability Margin for the stated flight condition (ii) Appraise the Neutral Point of the aircraft (iii) What will be the elevator setting for the stated flight condition 14 77 --12⁰ 1=0⁰ 77= 20 n = 40/nIf the maximum elevator angle for this aircraft is -12°. The variation of CM VS CL plots at other CG location is presented in Figure 1(b) below SINGAPORE UNIVERSITY OF SOCIAL SCIENCES (SUSS) [Course code] Pitching Moment Coefficient CM 12 0.25 0.2, 0.15 0.1 0.05 o -0.05 --01 -0.15 -0.2 0 0,2 0,4 CM VS CL 0,6 0,8 Lift Coefficent 12 Tutor-Marked Assignment CG @ 0.25 14 1,6 CG @ 0.2 Page 3 of 11 CG @ 0.15 Figure 1(b) C vs C₁, at various CG Locations If the stall speed at sea level for the aircraft is Vstall = 80 m/s, based on the data presented at Figure 1(b), what will be the suitable design for the forward limit of the CG location.