An aircraft is flying trim-stick-fixed and at standard sea level conditions. The aircraft mass is 40000 kg. The wings' surface area is 60 m, the chord of the rectangular wings is 2 m, the tail arm is 10 m and the tail plane area is 5 m. The ratio of the tail plane lift to the total lift is -0.03. Ground effect reduces the down-wash angle by 0.25 degrees. The rest of the known data is given in the two tables at the end of the question. Justify any assumption that you make. a) Calculate the total lift and tail plane lift coefficients, and the aircraft's speed. b) Calculate the down-wash angle and the tail plane incidence. c) Find the hinge moment coefficient and elevator angle. de/dCL [8 marks] d) Calculate the C.G. margin, how the elevator angle changes with the aircraft speed and how it affects the stick. 5 a 5.7 rad- a 3.2 rad- -0.15 a T 1.3 rad- 10 Lift curve slopes and hinge moment curve slopes b a3 0.8 rad-1 ho 0.06 0.2 rad- b [10 marks] -0.5 rad- [5 marks] [11 marks] h 0.2 b3 -0.02 rad- You may find the following expression useful Cm = Cmo + (h h)C V,C, V.. = C = aa + an+az CH=ba + bn + b3 a = a +T - de H = hoh + V (1 - da) h+ STlT Swe