Using the same flight conditions and the same value of the skin-friction coefficient from Example 12.3, and the results of Problem 12.6, calculate the maximum lift-to-drag ratio of the flat plate that is used to simulate the F-104 wing and the angle of attack at which it occurs.

Data from Problem 12.6:

Consider a flat plate at an angle of attack in a viscous supersonic flow; i.e., there is both skin friction drag and wave drag on the plate. Use linear theory for the lift and wave-drag coefficients. Denote the total skin friction drag coefficient by C _f , and assume that it does not change with angle of attack. (a) Derive the expression for the angle of attack at which maximum lift-to-drag ratio occurs as a function of C _f and freestream Mach number. (b) Derive the expression for the maximum lift-to-drag ratio as a function of C _f and freestream Mach number M.

Example 12.3:

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VYRT∞ = √(1.4)(287) (216.78) = 295 m/s ax = Voo = Moodoo = (2) (295) 590 m/s