Avit 323 Exam 2 UPDATED ACTUAL Exam
Questions and CORRECT Answers
Form drag - CORRECT ANSWER - Caused by pressure differences between the forward
and the aft surfaces (adverse pressure gradient)
How do you reduce form drag? - CORRECT ANSWER - Streamlining, but it increases
skin friction drag
What happens to parasite drag if we climb at a constant IAS? - CORRECT ANSWER -
Constant IAS = TAS increase, but parasite drag remains the same
Profile drag - CORRECT ANSWER - Parasite drag (skin friction) of the wing
What kind of wing do you want for low profile drag and high speed? - CORRECT
ANSWER - High wing
How do you reduce profile drag? [3] - CORRECT ANSWER - Laminar flow
Wingsweep
Streamlining
Problems with designs that reduce profile drag? [2] - CORRECT ANSWER - Must fly at
higher speed to generate lift
High induced drag at slow airspeeds
Interference drag - CORRECT ANSWER - Drag at airframe joints
When is interference drag the worst? - CORRECT ANSWER - Low wing aircraft with a
dihedral because of the acute angle between the wing and the fuselage
, How do you reduce interference drag? - CORRECT ANSWER - Streamlining and farings
Open vs closed cowl flaps - CORRECT ANSWER - Open- more cooling, but more drag;
more drag because of an increase in parasite drag
Closed- less cooling, less drag
Equivalent flat rate area - CORRECT ANSWER - The overall draginess of an airplane
compared to a flat, 1 sqft area
What causes induced drag? [2] - CORRECT ANSWER - Deflection of the relative wind
Wingtip vortices
What deflects relative wind? [2] - CORRECT ANSWER - Bound vortex
Wingtip vortices
Why does induced drag decrease with increasing speed? - CORRECT ANSWER -
Because you no longer need the increased AOA
Sphere of influence - CORRECT ANSWER - The volume of air that will be deflected
When is sphere of influence the greatest? - CORRECT ANSWER - High aspect ratio
Why do low aspect ratio has a higher induced drag? - CORRECT ANSWER - Because
wingtip vortices will influence a greater portion of the wing
Vectors of induced drag - CORRECT ANSWER - More deflection of the relative wind =
lift vector tilts away from the ideal vertical vector
Questions and CORRECT Answers
Form drag - CORRECT ANSWER - Caused by pressure differences between the forward
and the aft surfaces (adverse pressure gradient)
How do you reduce form drag? - CORRECT ANSWER - Streamlining, but it increases
skin friction drag
What happens to parasite drag if we climb at a constant IAS? - CORRECT ANSWER -
Constant IAS = TAS increase, but parasite drag remains the same
Profile drag - CORRECT ANSWER - Parasite drag (skin friction) of the wing
What kind of wing do you want for low profile drag and high speed? - CORRECT
ANSWER - High wing
How do you reduce profile drag? [3] - CORRECT ANSWER - Laminar flow
Wingsweep
Streamlining
Problems with designs that reduce profile drag? [2] - CORRECT ANSWER - Must fly at
higher speed to generate lift
High induced drag at slow airspeeds
Interference drag - CORRECT ANSWER - Drag at airframe joints
When is interference drag the worst? - CORRECT ANSWER - Low wing aircraft with a
dihedral because of the acute angle between the wing and the fuselage
, How do you reduce interference drag? - CORRECT ANSWER - Streamlining and farings
Open vs closed cowl flaps - CORRECT ANSWER - Open- more cooling, but more drag;
more drag because of an increase in parasite drag
Closed- less cooling, less drag
Equivalent flat rate area - CORRECT ANSWER - The overall draginess of an airplane
compared to a flat, 1 sqft area
What causes induced drag? [2] - CORRECT ANSWER - Deflection of the relative wind
Wingtip vortices
What deflects relative wind? [2] - CORRECT ANSWER - Bound vortex
Wingtip vortices
Why does induced drag decrease with increasing speed? - CORRECT ANSWER -
Because you no longer need the increased AOA
Sphere of influence - CORRECT ANSWER - The volume of air that will be deflected
When is sphere of influence the greatest? - CORRECT ANSWER - High aspect ratio
Why do low aspect ratio has a higher induced drag? - CORRECT ANSWER - Because
wingtip vortices will influence a greater portion of the wing
Vectors of induced drag - CORRECT ANSWER - More deflection of the relative wind =
lift vector tilts away from the ideal vertical vector
