More on Aeroplane Aerodynamics

Question 1

CL Eq for min D

Answer 1

CL = sqrt(πeAR*CD0)

Question 2

CL Eq for P min

Answer 2

CL = sqrt(3πeAR*CD0)

Question 3

Graphs of D vs v∞ and P vs v∞

Answer 3

Both graphs are visually similar, a +ve parabola that is slightly skewed to the right and both have a tangent to the graph through the origin.
The power graph has a minimum to the left of the minimum of the Drag graph
The velocity at Pmin is smaller than the velocity at Dmin

Question 4

Primary purpose of wing sweep

Answer 4

Shifting the Macr closer to 1, thus delaying the onset of wave drag. Generally used on aeroplanes that fly in or near the transsonic region

Question 5

Characteristics of Delta wings

Answer 5

Shaped like a triangle, they are designed to lie inside the shock wave or mach cone in order to avoid a complex shockwave pattern that has high drag.

The mach cone angle, μ, reduces as the velocity increases thus giving delta wing aircraft an optimal flight velocity based on the geometry of their wings