CH. 3 A Aerodynamic Principles (VOCAB)

Question 1

LIFT

Answer 1

The upward force created by the effect of airflow over and under the wing

Question 2

WEIGHT

Answer 2

Downward pull of gravity

Question 3

THRUST

Answer 3

Force which propels airplane forward

Question 4

DRAG

Answer 4

Backward, or retarding, force which limits the speed of the airplane

Question 5

VECTORS

Answer 5

Arrows that show the force acting on an airplane

Question 6

NEWTON’S 3 LAWS OF MOTION

Answer 6

1. Newton’s first law states that a body in rest tends to remain at rest, and a body in motion tends to remain moving at the same speed and in the same direction
2. Newton’s second law states that when a body is acted upon by a constant force, its resulting acceleration is inversely proportional to the mass of the body and is directly proportional to the applied force. force= mass x acceleration (F=ma)
3. Newton’s third law states that for every action there is an equal and opposite reaction

Question 7

BERNOULLI’S PRINCIPLE

Answer 7

Bernoulli’s principle states that as the velocity of a fluid (air) increases, its internal pressure decreases

Question 8

AIRFOIL

Answer 8

Any surface, such as a wing, which provides aerodynamic force when it interacts with moving stream of air

Question 9

LEADING EDGE

Answer 9

The front of the wing

Question 10

TRAILING EDGE

Answer 10

The back of the wing

Question 11

UPWASH

Answer 11

The deflection of the oncoming airstream upward and over the wing

Question 12

DOWNWASH

Answer 12

The downward deflection of the airstream as it passes over the wing and past the trailing edge

Question 13

ANGLE OF ATTACK

Answer 13

The angle formed by the wing chord line and relative wind

Question 14

WHAT ARE THE FOUR FORCES ACTING ON AN AIRPLANE IN FLIGHT?

Answer 14

Lift, weight, thrust & drag

Question 15

WHAT IS UNACCELERATED FLIGHT?

Answer 15

Straight-and-level flight when lift=weight & thrust=drag

Question 16

VENTURI

Answer 16

[picture]

Question 17

RELATIVE WIND

Answer 17

The airflow which is parallel to and opposite the flight path of an airplane

Question 18

COEFFICIENT OF LIFT

Answer 18

(CL) A way to measure lift as it relates to angle of attack. Every airplane has an angle of attack maximum lift occurs

Question 19

What causes a stall?

Answer 19

Caused by the separation of airflow from the wing’s upper surface. A stall always occurs at the same angle, regardless of airspeed, flight attitude, or weight

Question 20

CRITICAL ANGLE OF ATTACK

Answer 20

Angle at which the plane will stall

Question 21

BOUNDARY LAYER / TYPES

Answer 21

Thin layer of air above the wing’s surface showing the a reduction in speed to air’s viscosity or stickiness
Laminar Boundary Layer - smooth air
Turbulent Boundary Layer - turbulent air

Question 22

ASPECT RATIO

Answer 22

Aspect Ratio=Span/Average Chord

Question 23

PLANFORM

Answer 23

Overhead view of an aircraft

Question 24

2 TYPES OF DRAG

Answer 24

1. Parasite Drag
   beings at forward movement
   (form drag)-shape effect
   (interference drag)-protruding objects causing interference
   (skin friction drag)-speed=more friction slow=less friction
2. Induced Drag
   begins at lift
   reduce angle of attack, reduce lift, reduce induced drag
   byproduct of lift bc of the rearward component of lift

Question 25

Va

Answer 25

Maneuvering speed - is the speed is at which full and abrupt controlled movements can be imputed and the airplane will stall before it will reach its maximum structural limits

Question 26

LD MAX

Answer 26

Maximum Lift / Minimum Drag (point where induced drag and parasite drag meet on the drag curve) = resulting in best glide

Question 27

WHAT PRODUCES INDUCED DRAG?

Answer 27

Induced drag is the rearward component of lift caused by the downwash & wing tip vortices

Question 28

WHAT IS CONFIGURATION?

Answer 28

The position of the landing gear and flaps

Question 29

VASI / PAPI

Answer 29

Visual approach slope indicator

Precision approach path indicator

Question 30

DISPLACED THRESHOLD

Answer 30

NOBODY IS ALLOWED to land in the displaced threshhold Must land on the runway (past the cheverons - begins at the white line- touchdown zone)
YOU CAN taxi and begin roll in displaced threshold

Question 31

STANDARD TRAFFIC PATTERN

Answer 31

Left pattern

Question 32

NONSTANDARD TRAFFIC PATTERN

Answer 32

Right pattern

Question 33

GROUND EFFECT

Answer 33

Associated with the reduction of induced drag.
Disruption of three-dimensional airflow pattern around plane causing a reduction in wingtip in wingtip vortices and a decrease in upwash and downwash.

Question 34

RELATIONSHIP BTWN GROUND EFFECT AND INDUCED DRAG

Answer 34

In ground effect, induced drag is decreased and excess speed in the flare may cause floating when the plane is within one wingspan above the ground

Question 35

STABILITY

Answer 35

The characteristic of a plane in flight that causes it to return to a condition of equilibrium, or steady flight, after it is disturbed

Question 36

POSITIVE STATIC STABILITY

Answer 36

The initial tendency to return to the position from which it was displaced

Question 37

POSITIVE DYNAMIC STABILITY

Answer 37

The period of time through a series of successivley smaller oscillations the aircraft displays

Question 38

THREE AXES OF FLIGHT

Answer 38

Longitudinal (roll / ailerons)
Lateral (pitch / elevator)
Vertical (yaw / rudder)

Question 39

CENTER OF GRAVITY (CG)

Answer 39

The theoretical point where the entire weight of the airplane is considered to be concentrated

Question 40

CENTER OF PRESSURE

Answer 40

The point along the chord line where lift is considered to be concentrated aka Center of Lift

Question 41

CG RANGE

Answer 41

The distance btwn the forward and aft limits for the position of the CG

Question 42

UNACCELERATED FLIGHT

Answer 42

The four forces are in equilibrium

Question 43

The airplane’s wing’s shape is designed to take advantage of which principle(s)?

Answer 43

Newton’s law and Bernoulli’s principle

Question 44

Identify three methods you can use to control lift during flight

Answer 44

Lift is controlled by airspeed, changing angle of attack or flaps

Question 45

Will the wing’s angle of attack increase or decrease when trailing edge flaps are lowered?

Answer 45

Increase

Question 46

Is it more desirable for the wing root or wingtips to stall first and why?

Answer 46

Wing root - If wingtips stall before the root, the disrupted airflow near the wingtip can reduce aileron effectiveness to such an extent that it may be impossible to control the airplane about tits longitudinal axis

Question 47

Explain why induced drag increases as airspeed decreases

Answer 47

Induced drag is caused by the downwash created by wingtip vortices formed when the wing is generating lift. As the air pressure differential between the upper and lower surfaces of the wing becomes greater with an increase in angle of attack. stronger vortices form and induced drag is increased. Since the wing is usually at a a low angle of attack at high speeds, and a high angle of attack at low speeds, a relationship between induced drag and speed can be determined. induced drag is inversely proportional to the square of the speed

Question 48

The reduction in the induced drag due to ground effect is most noticeable when the airplane is within what distance from the earth’s surface?

Answer 48

One wingspan