2. An airplane (mass 10,000 kg, wing span 29.41 m, wing area 91.70 m2) travels at an altitude of 18,000 ft. Its wing uses an airfoil with a lift slope of 0.1 deg-1.

a. Using the estimation methods for the Oswald efficiency factor shown in the lecture (for straight wings), calculate the angle of attack for level flight (in degree). b. Using Matlab or Excel, plot the drag polar for the airplane. Assume a symmetric airfoil and a zero-lift drag coefficient of 0.01. Use the angle-of-attack range 0 - 15 in 0.5 steps. Clearly describe your approach and attach the plot. c. The airplane has 1,500 kg of fuel on board, which is part of its total mass. The SFC is 3 . The propellers have an efficiency of 85%. Assume a L/D ratio of 17. Calculate its total range in km, consisting of (i) powered flight and (ii) gliding.