review 4

Question 1

The drag of an airfoil is determined by it’s _____and _____. It’s minimum value is found at____ degrees angle of attack

Answer 1

shape/ angle of attack/ zero

Question 2

3 types of drag in forward flight

Answer 2

parasite, profile, & induced

Question 3

When the speed increases from 20 to 60 knots, parasite drag increases

Answer 3

nine

Question 4

form drag can be reduced by

Answer 4

shaping

Question 5

skin friction drag is caused by friction between molecules in the boundary layer which is an ____layer of air between the airfoil and the relative flow

Answer 5

accelerated

Question 6

A laminar boundary layer is normally ____

it produces ____ skin friction drag and it is readily subject to separation from airfoil surface

Answer 6

thin, little

Question 7

A turbulent boundary layer is normally ____

it produces aloota skin friction. it is not readily subject to separation from the airfoil surface

Answer 7

thick

Question 8

the point where laminar boundary changes into the turbulent boundary layer is called the

Answer 8

transition point

Question 9

with an increase in airspeed, skin friction drag ____
because the transition point moves ___
the boundary layer

Answer 9

increases forward thickens

Question 10

induced drag is the result of differences in ___ above and below the airfoil it is directly proportional to induced flow

Answer 10

pressure

Question 11

with an increase in airspeed, induced drag _____

parasite drag _____

Answer 11

decreases

increases

Question 12

increase in aspect ratio ___induced drag

Answer 12

decrease

Question 13

total drag is ____at zero airspeed
it decreases with an increase of airspeed
beyond medium airspeed it increases

Answer 13

high