Chapter 11: Aircraft Drag

Question 1

Drag Tree

Answer 1

Drag = Parasite + Induced (3D)
Parasite =  Profile (2D) + Interference (3D)
Profile = Skin (2D) + Form (2D)

Question 2

Drag Relationship to V and AoA

Answer 2

Parasite prop. to IAS^2
Induced prop. to 1/IAS^2

If same IAS, same drag (even at different altitudes)
for small AoA, Cdp is constant

Question 3

Form Drag Dependence (4)

Answer 3

Airspeed
Frontal area
Shape and streamlining
Surface roughness (rough = better)

Question 4

Skin Friction Dependence (4)

Answer 4

Airspeed
Surface area
Boudary layer type
Surface roughness

Question 5

Interference Drag Dependence (2)

Answer 5

Fillets

Fairings