Ch 3A - Four Forces of Flight

Question 1

Four forces acting on an airplane

Answer 1

Life, weight, thrust, and drag

Question 2

Four forces are in equilibrium

Answer 2

During unaccelerated flight

Question 3

Force created by the effects of airflow as it passes over and under the wing

Answer 3

Lift

Question 4

The airplanes wing shape is designed to take advantage of

Answer 4

Newton’s laws and Bernoulli’s principles

Question 5

Bernoulli’s principle

Answer 5

Increase in speed of air on the top of an airfoil produces a drop in pressure and this lowered pressure is a component of total lift. The decrease in speed of air on the bottom of the airfoil produces an increase in pressure, providing the main component of total lift

Question 6

Newton’s third law of motion

Answer 6

The reaction to downwash causes an upward reaction

Question 7

Design factors that affect a wings lifting capability

Answer 7

Planform, camber, aspect ratio, wing area

Question 8

A stall is caused by

Answer 8

The separation of airflow from the wings upper surface, and always occurs at an airplanes critical angle of attack regardless of airspeed, attitude or weight

Question 9

Total lift depends on

Answer 9

The combined effects of airspeed and angle of attack

Question 10

When speed decreases

Answer 10

ou must increase the angle of attack to maintain the same amount of lift

Question 11

Flaps

Answer 11

Increase lift and drag by increasing the wings effective camber and changing the chord line that increases the angle of attack

Question 12

Flap types

Answer 12

Plain(hinge), split(only lower hinged), slotted(plane w/gap) and fowler(slide out w/gap)

Question 13

Weight

Answer 13

Force of gravity that acts vertically through the center of gravity of the airplane towards the center of the earth

Question 14

Thrust

Answer 14

Forward-facing force that opposes drag and propels the airplane

Question 15

Drag

Answer 15

Acts in opposition to the direction on flight and opposes thrust, limits the forward speed of an airplane

Question 16

Parasite drag

Answer 16

Caused by surface that deflects or interferes with the smooth airflow around the airplane; form, interference, skin friction; airspeed doubled = 4X parasite drag

Question 17

Induced drag

Answer 17

Airflow circulation around the wings as it creates lift, increases with slow airspeed

Question 18

Ground effect

Answer 18

Surface restricts the downward deflection of the airstream from the wing, decreasing induced drag, airplane takes off before recommended take off speed

Question 19

Straight, level, unaccelerated flight

Answer 19

Lift=weight and thrust=drag

Question 20

Angle of attack

Answer 20

Formed by wing chord line and relative wind

Question 21

Aspect ratio

Answer 21

Span(long)/average chord(short)