Question 3) (a) at 5 points, b), c) & d) at 10 points each) The pilot of an F-16 wants to maintain a constant altitude of 30,000 ft flying at idle power. We remind that for flight in a horizontal plane (i.e., constant altitude), where the angles are small, the lift must balance the weight of the aircraft, which is 23,750 pounds. Therefore, as the vehicle slows down, the pilot must increase the angle of attack of the aircraft in order to increase the lift coefficient to compensate for the decreasing velocity (and dynamic pressure). The lift curves for the F-16 aircraft, were provided by the General Dynamics Staff (1976) and are presented in Figure 2 for several Mach numbers. Assume that the lift curve for M = 0.2 is typical of that for incompressible flow. The minimum flight speed (i.e., the stall speed) is the velocity at which the vehicle must fly at its limit angle of attack in order to generate sufficient lift to balance the aircraft's weight. The wing reference area S is 300 ft2. a) Quantitatively, at which angle of attack would the minimum possible stall speed occur for the F-16 at 30,000 ft? b) Calculate the minimum velocity (i.e. the stall speed) at which the weight of the F-16 is balanced by the lift at 30,000 ft, for the angle of attack you assumed in a). c) Assuming that for all Mach numbers shown on Figure 2 the flow is incompressible, populate all five rows of the table below, clearly showing the steps that lead to your results: Moo CL a (0 ) Voo (ft/s) Voo (knots) 1.2 0.9 0.8 0.6 27.5 d) Prepare a graph of the angle of attack as a function of the air speed in knots (nautical miles per hour) as the aircraft decelerates from a Mach number of 1.2 until it reaches its minimum flight speed. What conclusions do you draw based on this plot?

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