Question

3. The total drag on an airfoil can be estimated using:

where the first term is due to friction and the second term is due to the lift. D=drag,

W=weight, V=velocity, and o-ratio of air density at flight altitude to at sea level.

Friction increases with velocity while drag due to lift decreases, and when combined

there is a velocity of minimum drag:

a. Determine the minimum drag and the velocity at which it occurs for

W = 16,000 and o= 0.6. Copy and paste the relevant commands and results

from MATLAB. You may use any of the three functions from Problem 1.

b. Plot the optimum velocity vs weight if you vary the weight from 12,000 to

20,000. Attach a copy of the graph to your homework, making sure to properly

format and label the graph.

Fig: 1

Fig: 2