Question 4 (Finite Wings) - 15 Marks Solve the following questions: a. b. C. Consider a vortex filament of strength I in the shape of a closed circular loop of radius R. Obtain an expression for the velocity induced at the center of the loop in terms of I and R. The Piper Cherokee (a light, single-engine general aviation aircraft) has a wing area of 170 ft and a wing span of 32 ft. Its maximum gross weight is 2450 lb. The wing uses an NACA 65-415 airfoil, which has a lift slope of 0.1033 degree and =0 = -3. Assume r = 0.12. If the airplane is cruising at 120 mi/h at standard sea level at its maximum gross weight and is in straight-and-level flight, calculate the geometric angle of attack of the wing. Consider the airplane and flight conditions given in Problem 4(b). The span efficiency factor e for the complete airplane is generally much less than that for the finite wing alone. Assume e = 0.64. Calculate the induced drag for the airplane in Problem 5.4.