# Aerodynamic Flight Performance: Steady, Level, and Unsteady Flight Practice Problems

An airplane weighing 5000 lb is flying at standard sea level with a velocity of 200 mi/h. At this velocity, the L/D ratio is a maximum. The wing area and aspect ratio are 200 ft.2 and 8.5, respectively. The Oswald efficiency factor is 0.93. Calculate the total drag on the airplane.

1. Consider an airplane patterned after the Fairchild Republic A-10, a twin-jet attack aircraft. The airplane has the following characteristics: wing area = 47 m2, aspect ratio = 6.5, Oswald efficiency factor = 0.87, weight = 103,047 N, and parasite drag coefficient =0.032. The airplane is equipped with two jet engines with 40,298 N of static thrusts each at sea level.
1. Calculate and sketch the power required curve at sea level.
1. Calculate the maximum velocity at sea level.
1. Calculate and plot the power required curve at 5 km altitude.
1. Calculate the maximum velocity at 5 km altitude. (Assume the engine thrust varies directly with free stream density.)
1. V-tailed, single engine light private airplane. The characteristics of the airplane are as follows: aspect ratio = 6.2, wing area = 181 ft.2, Oswald efficiency factor = 0.91, weight = 3000 lb, and parasite drag coefficient = 0.027. The airplane is powered by a single piston engine of 345 hp maximum at sea level. Assume the power of the engine is proportional to free stream density. The two-bladed propeller has an efficiency of 0.83.
1. Calculate the power required at sea level.
1. Calculate the maximum velocity at sea level.
1. Calculate the power required at 12,000 ft. altitude.
1. Calculate the maximum velocity at 12,000 ft. altitude.