Question

A jet aircraft is in level flight at an altitude of 30,000 ft with an airspeed of 500 ft/s. The aircraft has a gross weight of 19,815 lb, a wingspan of 53.3 ft, and an average chord length of 6 ft. The Oswald efficiency factor is 0.81 and the zero-lift drag coefficient is equal to 0.02. The jet has two turbofan engines, each producing a maximum thrust of 3,650 lb at sea level.

Required:
a. Create a plot of the drag polar for this aircraft for CL from 0 to 5. Plot CL on the vertical axis, CD on the horizontal axis, and do not include negative CL values.
b. What is the total drag coefficient at the flight condition described above?
c. What is the required thrust for level flight at this altitude in lb?
d. If the pilot runs the engines at maximum thrust, what is the instantaneous rate of climb at this altitude and velocity?

Answer 1

a) attached below

b) 0.0337

c) 2730.206 Ib

d) 2320.338 ft/min

Step-by-step explanation:

a) Plot of the drag polar for this aircraft

first we will calculate :

Wing area (s) = Wing span (b) * Average chord length(c)

= 53.3 * 6 = 319.8 ft^2

Aspect ratio = b^2 / s = 8.883

K = 1 /
`\pi`eAR = 1 /

Drag polar ( Cd ) = 0.02 + 0.044 C^2L

attached below is a plot of the drag polar

Attached below is the detailed solution of the remaining part of the question