Module 6 - High Speed Wings and Surface Controls, and High Lift Devices

Question 1

refers to the shape and layout of the fuselage and wing of a fixed wing aircraft

Answer 1

planform

Question 2

constant chord wings which are the easiest to manufacture

Answer 2

rectangular wings

Question 3

wing shape most commonly used for trainer and subsonic aircraft

Answer 3

rectangular wings

Question 4

disadvantage of rectangular wings

Answer 4

not aerodynamically efficient compared to other wing designs

Question 5

most aerodynamically efficient type of wing

Answer 5

elliptical wings

Question 6

why are elliptical wings considered the most aerodynamically efficient type of wing

Answer 6

because of the elliptical spanwise lift distribution that it generates in flight

Question 7

produce the lowest possible drag of all the wing planforms

Answer 7

elliptical wing

Question 8

wing shape that allowed for the thinnest possible wing

Answer 8

elliptical wing

Question 9

were designed to modify the rectangular wing planform where the chord essentially varies along the span of the wing to generate an elliptical spanwise lift distribution

Answer 9

tapered wings

Question 10

wing shape that offers a good compromise between efficiency and manufacturability

Answer 10

tapered wings

Question 11

low aspect ratio wings that are used in all flight regimes

Answer 11

delta wings

Question 12

this type of wing is generally efficient for high speeds and exhibits high drag at low speeds

Answer 12

delta wing

Question 13

example of a delta wing employed in the Concorde

Answer 13

ogive wing

Question 14

advantage of delta wings

Answer 14

better maneuverability and greater fuel capacity

Question 15

disadvantage of delta wings

Answer 15

• produces high drag
• can only be used for high speeds
• complex and difficult to manufacture

Question 16

reduces the aerodynamic drag as the aircraft fly at high speed subsonic or transonic speeds

Answer 16

swept wings

Question 17

types of swept wings

Answer 17

• swept back
• swept forward
• variable sweep

Question 18

aircraft wings whose leading edges are swept back

Answer 18

swept back wings

Question 19

aircraft wings whose leading edges are swept forward

Answer 19

forward-swept wings

Question 20

disadvantages of forward-swept wings

Answer 20

• stalls the wing tip before the wing root which makes it undesirable for controllability
• produces wing twisting when put under load which puts greater stress on the wing root

Question 21

designed to compensate for which regimes each planform are efficient

Answer 21

variable sweep wings

Question 22

disadvantages of variable sweep wings

Answer 22

harder to manufacture and mechanical complexity

Question 23

the primary control surfaces of an airplane include:

Answer 23

• ailerons
• rudder
• elevator

Question 24

what are the

• airplane movement
• axis of rotation
• type of stability

for an aileron

Answer 24

• roll
• longitudinal
• lateral

Question 25

what are the - airplane movement - axis of rotation - type of stability for a rudder

Answer 25

- yaw - vertical - directional

Question 26

what are the - airplane movement - axis of rotation - type of stability for an elevator

Answer 26

- pitch - lateral - longitudinal

Question 27

what controls the elevators of an aircraft?

Answer 27

control wheel or yoke

Question 28

elevator: pulling the control wheel causes the elevator to deflect ___________

Answer 28

upward

Question 29

elevator: pushing the control wheel causes the elevator to deflect ___________

Answer 29

downward

Question 30

the effectiveness of the elevator in generating the pitching moment depends on the __________________

Answer 30

moment principle

Question 31

distance of the applied force from the aircraft center of gravity

Answer 31

moment principle

Question 32

configurations of elevator in aircraft design

Answer 32

- t-tail design - stabilator - canard

Question 33

elevators for this configuration are placed away from the effects of downwash from the propeller and airflow around the wing during normal flight conditions

Answer 33

t-tail design

Question 34

which elevator configuration allows for tail mounted engines?

Answer 34

t-tail design

Question 35

at high angles of attack, the t-tail design is highly susceptible to _____________

Answer 35

deep stall

Question 36

a movable horizontal surface that acts as an elevator

Answer 36

stabilator

Question 37

functions just like an elevator but is essentially a one-piece control surface rotated about a central hinge point

Answer 37

stabilator

Question 38

stabilator: pulling the control wheel causes the stabilator to deflect ___________

Answer 38

downwards

Question 39

stabilator: pushing the control wheel causes the stabilator to deflect ___________

Answer 39

upwards

Question 40

__________ designs utilize concepts of two lifting surfaces

Answer 40

canard

Question 41

acts as a control surface near the nose of the aircraft designed to create lift to pitch the nose up

Answer 41

canard

Question 42

the rudder is hinged to a fixed vertical surface called the _____ or vertical stabilizer and is controlled by ______________

Answer 42

fin, rudder pedals

Question 43

rudder effectiveness increase with _________

Answer 43

speed

Question 44

combine functions of elevators and rudders by employing slanted vertical tail surfaces

Answer 44

v-tail designs

Question 45

since v-tail designs acts as both elevators and rudders, as well as horizontal and vertical stabilizers, it is usually called _______________

Answer 45

ruddervators

Question 46

primary concern for v-tail designs

Answer 46

susceptibility to flutter or rapid vibration

Question 47

usually mounted on the outer part of the wing trailing edge (or near the wing tips) and move opposite relative to each other

Answer 47

ailerons

Question 48

the tendency for an aircraft to yaw in the opposite direction than intended

Answer 48

adverse yaw

Question 49

when an aileron is deflected upward, it creates a/an _____________ in wing camber resulting in a/an ____________ in lift

Answer 49

decrease, decrease

Question 50

when an aileron is deflected downward, it creates a/an _____________ in wing camber resulting in a/an ____________ in lift

Answer 50

increase, increase

Question 51

forms of controlling the adverse yaw

Answer 51

- differential ailerons - frise-type ailerons - coupled ailerons and rudder - flaperons

Question 52

operated in such a way that one aileron is deflected at a larger angle corresponding to the control wheel input

Answer 52

differential ailerons

Question 53

what happens to the adverse yaw when differential ailerons are applied

Answer 53

adverse yaw is reduced but not eliminated completely

Question 54

operated by pivoting on an offset hinge

Answer 54

frise-type ailerons

Question 55

operates by automatic rudder deflection for every control input done on the control wheel

Answer 55

coupled ailerons and rudder

Question 56

are control surfaces that combine the aspects of ailerons and flaps

Answer 56

flaperons

Question 57

are moveable surfaces or, in some cases, stationary components that are designed to increase lift during some phases or conditions of flight

Answer 57

high lift devices

Question 58

three groups of high lift devices

Answer 58

- trailing edge flap - leading edge high lift devices or leading edge devices - boundary layer control

Question 59

high lift device consisting of a hinged panel or panels mounted on the trailing edge of the wing

Answer 59

trailing edge flaps

Question 60

types of trailing edge flaps

Answer 60

- plain flap - split flap - slotted flap - fowler flap

Question 61

is the simplest and earliest type of high lift device

Answer 61

plain flap

Question 62

only the bottom part of the airfoil is movable which leaves the upper geometry of the airfoil unchanged during flap deflections

Answer 62

split flap

Question 63

opens a gap or slot between the flap and the main airfoil when it is deflected

Answer 63

slotted flap

Question 64

types of slotted flap

Answer 64

- single slotted flap - double slotted flap - triple slotted flap

Question 65

most commonly used type of flap

Answer 65

slotted flap

Question 66

employs a special mechanism such that when it is deployed, not only it deflects downward but also translates or tracks to the trailing edge of the wing

Answer 66

fowler flap

Question 67

great instruments to increase the critical angle of attack and therefore, delay the stall

Answer 67

leading edge high lift devices

Question 68

types of leading edge devices

Answer 68

- fixed slot - leading edge slat (movable slat) - leading edge flap (droop-snoot) - leading edge cuff - Kruger flap

Question 69

directs airflow in the upper surface of the wing which in turn delays airflow separation at higher angles of attack

Answer 69

fixed slots

Question 70

designed as a small, highly cambered section located slightly forward in the leading edge of the wing

Answer 70

leading edge slat

Question 71

the same as the trailing edge flap with the exception that it is installed in the leading edge of the wing

Answer 71

leading edge flap

Question 72

used to increase the maximum lift coefficient and the camber of the wings

Answer 72

leading edge cuff

Question 73

essentially the same as the leading edge slat, however, it is made of a thinner profile and lies flush with the bottom surface of the wing when not deflected

Answer 73

Kruger flap

Question 74

the main purpose of this is to prevent or delay flow separation on an airfoil

Answer 74

boundary layer control

Question 75

types of boundary layer control

Answer 75

- boundary layer blowing - boundary layer suction - jet flap

Question 76

the working principle of ________________ is similar to the leading edge slat but instead of forming a slot for high pressure air to pass through, a narrow slit is used to blow high speed air in the upper surface of the airfoil

Answer 76

boundary layer blowing

Question 77

___________________ works in a principle of _________ which removes slowly moving air in the boundary layer

Answer 77

boundary layer suction, suction

Question 78

used to prevent laminar or turbulent separation

Answer 78

boundary layer suction

Question 79

used to re-energize the boundary layer

Answer 79

boundary layer blowing

Question 80

consists of a very high speed jet of air blown through a narrow slit in the trailing edge of the wing

Answer 80

jet flap