Chapter 12: Total Drag and the Drag Polar

Question 1

Drag Coefficient
Obtain? Vmd? Significant?
Vmd light AC? Commercial?

Answer 1

D = Di + Dp
Dmin, L/D @ AoA = 4 deg
Vmd ~= 1.3 Vs (light)
Vmd ~= 1.6 (commercial)

Question 2

Speed Stability (3)

Answer 2

Unstable (left curve)
Neutral (around Vmd)
Stable (right of curve)

Question 3

Cd Curve

Increase TAS with constant IAS?

Answer 3

IAS constant -> Cd / IAS curve doesnt change
IAS constant -> Cd / TAS curve offset right
Because for Dynamic pressure to remain constant, TAS needs to increase

Question 4

Cd /IAS Curve

Heavier Aircraft

Answer 4

Affects Cdi

Cd curve moves up (more lift induced drag) and Vmd is faster

Question 5

Cd/ IAS Curve

Flaps out

Answer 5

Affects Cdp

Cd curve moves up (more parasite drag) and Vmd is slower