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CPL > Aerodynamics > Flashcards

Aerodynamics Flashcards

0
Q

What is camber?

A

Curvature

Distance between mean camber line and chord line

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1
Q

What is the centre of gravity?

A

Weight of aircraft and point which balances can be found.

Acts towards centre of earth

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2
Q

What is mean camber line?

A

Line drawn halfway between upper and lower surfaces

Aka averse curvature

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3
Q

What is chord line?

A

Straight line joining leading edge and trailing edge of aerofoil

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4
Q

Where does lift act?

A

At right angles/perpendicular to relative airflow

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5
Q

Where does drag act?

A

Parallel to the relative airflow and opposing motion

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6
Q

What is the angle of attack?

A

Angle between the chord line and relative airflow

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7
Q

What is the centre of pressure?

A

Point on top of aerofoil where total reaction of all lifting aerodynamically forces said to act

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8
Q

What happens as angle of attack increases?

A

Lifting of wing increases

Centre of pressure moves forward

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9
Q

What is the primary effects of flaps?

A

Additional lift at slower speed
Increase drag
Shallower climbs

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10
Q

What is induced drag?

A

Drag forces associated with production of lift

Related to angle of attack, higher AoA, higher induced drag

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11
Q

What is parasite drag?

A

Not associated with development of lift

Higher the speed higher the drag

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12
Q

How is induced drag reduced?

A

Reducing span wise airflow
Fitting fences
Winglets
High aspect ratio

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13
Q

What is washout?

A

Pressure differential at wingtip is reduced if wing has inbuilt twist, reducing angle of incidence from wing root to tip

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14
Q

What are the benefits of washout?

A

Less severe wingtip vortices
Less induced drag
Less bending load on wing root

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15
Q

How close do you have to be to be in ground effect?

A

Approximately 1 wingspan

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16
Q

At 30 bank, what is the load factor and stalling speed?

A

Load 1.5

Stalling speed increased by 7%

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17
Q

At 60 angle of bank what is load factor and the stalling speed?

A

Load is 2 and stalling speed increased by 41%

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18
Q

What is the tendency of bank during climb?

A

Over bank in climb

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19
Q

What is the angle of incidence?

A

Angle between chord line of wing and longitudinal axis of plane

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20
Q

Where does lift act?

A

Centre of pressure

Right angle/perpendicular to relative airflow

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21
Q

What does dihedral wings do to stability?

A

Increases lateral stability

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22
Q

What forces are there in straight and level?

A

Weight balanced by lift
Drag balanced by thrust
Forces are in balance resulting in 0 force

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23
Q

What is the formula for wing loading?

A

Weight of aircraft/wing area

Kg/m squared

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24
Q

What is the boundary layer?

A

Airflow nearest to the surface of the Aerofoil

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25
Q

What is laminar flow?

A

Smooth airflow

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26
Q

What is the transition point?

A

Airflow within the laminar boundary later that becomes turbulent

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27
Q

What is turbulent flow?

A

Molecules of air not following a streamlined flow pattern.

This increases drag

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28
Q

What is the separation point?

A

Point at which boundary layer separates from surface of Aerofoil, causing main airflow to break away

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29
Q

What happens as you increase velocity?

A

Decreased static power

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30
Q

What does increasing camber of wing do?

A

Generate more lift at same angle of attack

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31
Q

Why is larger camber beneficial?

A

Good lift, suitable for low speeds and carrying heavy loads

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32
Q

What happens as AoA increase?

A

Lifting ability of winged increases
Centre if pressure moves forward
Airspeed decreases

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33
Q

What must happen in the TAS decreases to maintain straight and level?

A

AoA must increase to compensate

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34
Q

What does sharper leading edge and reduce camber do?

A

Less lift at higher AoA

Airflow separates more suddenly

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35
Q

What are slats?

A

Short chord aerofoil surfaces attached and extended along leading edge of wing

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36
Q

What are the benefits of laminar flow wing?

A

Higher cruise speeds
Lower fuel consumption
Greater range

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37
Q

What do slats provide?

A

Rounder leading edge

Increased lift at higher angle of attack and higher nose

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38
Q

What are leading edge flaps and what do they do?

A

Extend from leading edge to change curvature. Allows controlled flow and flight at higher angles of attack

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39
Q

What do flaps do?

A

Increase lift for same AoA
Increase drag
Decrease L/D ratio
Stalling angle is less

For takeoff, increased lift and stalling speed lower

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40
Q

What is induced drag?

A

Associated with production of lift

Related to AoA

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41
Q

What happens to skin friction drag as airspeed increases?

A

Increases

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42
Q

When are the strongest wing tip vortices?

A

When producing high amounts of lift

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43
Q

What are high aspect ratio wings and what do they do?

A

Long and narrow wings.
Weaker vortices
Less downwash and therefore less induced drag
Lower critical AoA but higher coefficient of lift
Harder to build

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44
Q

What is the aspect ratio for rectangle wings?

A

Span/chord

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45
Q

What is the aspect ratio for tapered wings?

A

Span squared / wing area

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46
Q

What is washout?

A

Inbuilt twist at wing route

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47
Q

What are the benefits of washout?

A

Less sever wingtip vortices
Less induced drag
Less bending load on wing root as lift generated inbound
Docile stall (inner wing stalls while outter still functions

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48
Q

What factors increase induced drag?

A

High AoA

Increase lift production requirement (steep turns)

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49
Q

What solutions are the for the ground effect?

A

Lift off at recommended speed
Don’t retract flaps prematurely
On hot days at high elevation, lift off at higher than normal speeds and don’t rotate till speed achieved

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50
Q

What type of drag is mainly at slow speed?

A

Induced

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51
Q

What type of drag is mainly at fast speeds

A

Parasite

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52
Q

At a constant weight what happens if the AoA is increased?

A

Required lift can be generated at lower speed

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53
Q

In straight and level, if weight is decreased what happens to lift?

A

Lift produced done at lower AoA which increases speed

Same IAS occurs at slightly lower AoA

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54
Q

What happens to AoA and IAS as we gain height?

A

Same weight and lift requirements

Same AoA and IAS. Increased TAS

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55
Q

What does a small prop on a big engine do?

A

Limits thrust to be obtained

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56
Q

What effect does a big prop on a small engine do?

A

Consumes available torque just to rotate

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57
Q

What is geometric pitch and is it effective?

A

When prop is moving forward
Prop is at 0 AoA
Not effective

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58
Q

What is the most effective AoA?

A

4 degrees

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59
Q

What is the best blade angle in comparison to blade length from hub?

A

75%

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60
Q

What is windmilling?

A

When prop drives the engine
Flattens pitch
CTM = ATM

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61
Q

What would be the best pitch for high rpm?

A

Fine pitch

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62
Q

What is the best pitch for low rpm?

A

Coarse pitch

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63
Q

The prop rotating clockwise (from cockpit) will push the tail to the right and yaw nose to the left. What is this?

A

Slipstream effect

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64
Q

What are the forces when a plane is in balance?

A

Total forces are in equilibrium

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65
Q

What is the balance point called?

A

Fulcrum

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66
Q

What are static forces?

A

Forces that act all the time (eg weight)

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67
Q

What are dynamic forces?

A

Forces caused by movement through the air (eg lift)

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68
Q

What causes lift and where does it act?

A

Caused by different static pressures at right angles to airflow
Total lifting forces act through centre of pressure

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69
Q

Where does weight act?

A

Acts vertically down through centre of gravity

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70
Q

Where does drag act?

A

Parallel to relative airflow

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71
Q

What happens if centre of pressure (lift) is behind the centre of gravity (weight)?

A

Nose will go down

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72
Q

What happens if the lift (centre of pressure) is forward of the weight?

A

Nose will go up

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73
Q

What happens if drag is above the thrust line?

A

Nose will go up

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74
Q

What happens is drag is below thrust line?

A

Nose will go down

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75
Q

What is the main affect of the tail plane?

A

Counteracts residual pitching moments

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76
Q

What is a fixed tab?

A

Small metal tab bent into set position

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77
Q

What is a trim tab?

A

Designed to remove stick force for set AoA and power

Reduces column control surface to zero, allows hands off

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78
Q

What is static stability?

A

Tendency of aircraft to return to original position after being disturbed
If it tends to return, statically stable

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79
Q

What is dynamic stability?

A 
Motion of body after disturbing force has been removed (oscillation)
If it stops immediately = well damped
If it stops slowly = slightly damped
Continues indefinitely = undamped
Gets worse = unstable
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80
Q

What is controllability?

A

Ease at which pilot can manoeuvre aircraft to overcome stability

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81
Q

What is the effect of increased stability?

A

Decreased controllability

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82
Q

What is stability around the longitudinal axis?

A

Lateral stability (aileron/roll)

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83
Q

What is stability around the lateral axis?

A

Longitudinal stability (pitch/elevator)

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84
Q

What is stability around the normal axis?

A

Directional stability (rudder/yaw)

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85
Q

What is angular motion?

A

Rotation around the point/axis

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86
Q

What is angular displacement?

A

Number of degrees of rotation

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87
Q

What is Angular velocity?

A

Speed at which angular displacement occurs

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88
Q

What will a forward centre of gravity do to stability?

A

Increase longitudinal stability
Greater the moment arm for tail place
Greater turning effect of tail

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89
Q

How can you increase directional stability?

A

Bigger fin area and keel surface behind the centre of gravity

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90
Q

How can you increase lateral stability?

A 
Dihedral wings (up)
Causes lower wing to produced increased amounts of lift
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91
Q

What occurs if lateral stability is weaker than directional stability?

A

Spiral instability

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92
Q

What happens if lateral stability is stronger than directional stability?

A

Dutch roll

Not turn in direction of slipstream

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93
Q

Where must the centre of gravity lie on the ground?

A

Between the wheels

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94
Q

If an aircraft is in a displaced yaw (sideslip), what will lateral stability cause?

A

Increased lift on forward wing

Decreased lift on trailing wing to roll out of sideslip

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95
Q

What is a stabilator?

A

All moving tail

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96
Q

Down going aileron is on which wing?

A

Up going wing

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97
Q

Up going aileron is on which wing?

A

Down going wing

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98
Q

What does the down going aileron cause?

A

Increased camber of wing
Increased AoA on wing
Increased lift and drag

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99
Q

What does the up going aileron cause?

A

Decreased camber of wing
Decrease AoA
Decreased lift and drag

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100
Q

When is adverse aileron yaw most likely to occur?

A

At slow speeds

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101
Q

What do differential ailerons do?

A

Up going aileron goes higher than down going aileron

Increased drag on up aileron/down wing

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102
Q

What will increase the effectiveness of the rudder?

A

Increased speed

Increase slipstream over rudder

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103
Q

What do Frise ailerons do?

A

Uses hinges to deflect part of upgoing aileron into air which increase drag on up going aileron (down wing)
As aileron goes up, it’s nose protrudes into airstream causing more drag

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104
Q

What are the primary effects of spoilers?

A

Increase drag and spoils lift

Increases rolling moment

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105
Q

Where are mass balances placed?

A

Forward of hinge line

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106
Q

What are balance tabs?

A

On elevator

Goes opposite direction of rudder to reduce control load

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107
Q

What is anti balance tab?

A

Goes same direction as elevator but higher
Increased stick force
Decreased over stressing structure

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108
Q

In straight and level flight, if airspeed reduces, what happens to lift?

A

Increases

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109
Q

What angle of attack is required for straight and level at slow speed?

A

High angle of attack

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110
Q

At high speed, what angle of attack is required?

A

Low angle of attack

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111
Q

What happens to angle of attack and speed as weight is reduced?

A

Airspeed must reduce

Angle of attack must reduce

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112
Q

What is required to overcome parasite drag?

A

High speed
Low AoA
Low induced drag

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113
Q

What thrust is required at low speeds to overcome induced drag?

A

High thrust

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114
Q

Which is faster, max range speed or max endurance?

A

Max range speed

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115
Q

What is maximum range speed?

A

Greatest distance for least fuel consumer
Time doesn’t matter
Approximately 20% slower than cruise

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116
Q

What is maximum endurance speed?

A 
Greatest time for available fuel
Distance doesn't matter
Power at minimum
Fly as low as possible
Similar to best rate of climb
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117
Q

What is speed stable?

A

Above minimum drag
Any minor speed fluctuation is self correcting
Increased speed = increased parasite drag, causing aircraft to slow

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118
Q

What is speed unstable?

A

Speeds below minimum drag
If gust causes speed to decrease, total drag increases, induced drag increases, drag will be greater then thrust and aircraft slows down

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119
Q

What is a zoom?

A

Exchanging speed for height

Temporary

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Perfectly
120
Q

What is the absolute ceiling?

A

Reduction in thrust due to increased altitude, reducing climb to zero

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121
Q

What is a climb?

A

Aircraft driven by excess thrust and sustains speed

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122
Q

What is the service ceiling?

A

When max rate of climb is reduced to 100 feet per minute

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123
Q

In a climb, what must the engines thrust overcome?

A

Drag at climb airspeed

Component of weight that acts negatively to climb path

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124
Q

What are the forces in a climb?

A

Thrust is greater than drag
Lift is less than weight
No acceleration

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125
Q

What happens to the angle of climb if the weight is reduced in max angle of climb?

A

Greater the angle of climb

126
Q

What happens to the angle if there is greater thrust in max angle of climb?

A

Greater angle of climb

127
Q

If there is less drag, what happens to the max angle of climb?

A

Greater angle of climb

128
Q

What is the max rate of climb close to?

A

Best lift drag ratio

129
Q

What happens if there is excess power in max rate of climb?

A

Greater the rate of climb

130
Q

What happens if there is less weight in max rate of climb?

A

Greater the rate of climb

131
Q

What happens if there is less drag in max rate of climb?

A

Greater the rate of climb

132
Q

What happens to angle of climb and rate of climb in headwind?

A

Rate stays the same

Angle of climb steeper

133
Q

What happens to the angle and rate of climb in a tailwind?

A

Angle shallows, rate remains the same

134
Q

What happens if you increase or decrease the speed in a glide?

A

Steeper glide

135
Q

What will coarsening the pitch in a glide?

A

Improve the glide

136
Q

What happens if you reduce the weight in a glide?

A

Lift will be less so to maintain same angle of attack, must reduce airspeed

137
Q

What happens to time and distance with a headwind?

A

Time will be same
Reduces glide distance
Steeper

138
Q

What happens with time and distance with a tailwind in a glide?

A

Time will be the same
Increases glide distance
Shallower

139
Q

What is the load factor formula?

A

1 / cos bank angle

140
Q

In a level turn with 30 degrees bank, what is the load factor and stall speed?

A

1.15

Stall speed increase by 7%

141
Q

In a level turn, what is the go with lift and angle of attack?

A

Lift is greater
Angle of attack increased
Steeper the turn, greater the lift required

142
Q

In a 60 degrees bank, what happens to load and stall speed?

A

Load 2

Stall speed increase by 41%

143
Q

In a 45 degrees turn, what happens to load and stall speed?

A

Load is 1.41

Stall speed 19% faster

144
Q

In a 75 degree turn, what happens to load and stall speed?

A

Load is 4

Stall speed increase by 100%

145
Q

What is the bank tendency in a level climbing turn?

A

Tendency to over bank

Outer wing travels faster than inner, generating more lift

146
Q

What is the tendency of bank in descending turns?

A

Tendency to underbank in descending turns

Inner wing travels smaller horizontal distance for same height loss, produces more lift

147
Q

What does and increased angle of bank do to rate and radius of turn?

A

Increased rate of turn

Decreased radius of turn

148
Q

What is the formula for a rate one turn?

A

(Airspeed / 10) + 7 = bank degrees for rate one turn

149
Q

What should you do if there if a headwind from your left on the ground?

A

Left aileron up

Tail up

150
Q

What should you do if there is a tail wind from the left?

A

Left aileron down

Tail down

151
Q

What does a headwind do to take off distance?

A

Reduces take off distance

No change to time

152
Q

What does ice on the wings do to stall speed?

A

Increases the stall speed

153
Q

What does a headwind do to approach?

A

Causes steeper approach

154
Q

What does windshear do to airspeed?

A

Decreases airspeed

155
Q

What will cause you to undershoot on approach?

A

Tail winds
Decreasing headwind
Downdraft

156
Q

What will cause you to overshoot on approach?

A

Headwinds
Decreasing tailwind
Updraft

157
Q

What motion will wake turbulence cause to other aircraft?

A

Strong rolling moment or downdraft

158
Q

When is wake turbulence caused?

A

During take off of slow heavy aircraft with flaps up

159
Q

How long and far is wake turbulence around for?

A

Descends 400/500 ft per minute and levels off at 900-1000

Can persist for up to 3 mins

160
Q

What will a light cross wind do to wake turbulence?

A

Move upwind vortex across the centre of runway

161
Q

What should you do to avoid wake turbulence?

A

Fly above and upwind of flight path

Touchdown beyond heavy aircrafts touchdown point

162
Q

What is thrust stream turbulence?

A

High velocity air exhausted from jet engine
At idle can reach speeds of 25 kts 30m behind
At full power can reach speeds of 125 kts 30 m behind

163
Q

What happens to coefficient of lift as angle of attack increase?

A

Increase

164
Q

What happens at the critical angle of attack or stalling angle?

A 
Streamline flow doesn't exist
Most airflow separates from aerofoil (separation point)
Separation point moves forward
Centre of pressure moves forward
Induced drag increases
165
Q

What happens beyond critical angle?

A 
Separation point moves well forward
Big increase in turbulence over wing
Increased drag
Decreased lift
Centre of pressure moves back
166
Q

What happens to the stall speed as you decrease weight?

A

Stall speed decreases

167
Q

When will the stall horn go off?

A

About 5-7 knots before stall

168
Q

What happens in a spin?

A

Outter wing speeds up and generates more lift causing it to rise and AoA to decrease
Inner wing slows and generates less lift causing it to drop and AoA increases

169
Q

How is the rate of turn and how many feet do you lose per turn?

A

Turn every 2-3s and lose approximately 300feet per turn

171
Q

What is the recovery for a spin?

A 
Close throttle
Opposite rudder
Column forward
Centralise rudder
Recover
172
Q

What is relative airflow?

A

Airflow opposite to direction of path of aircraft

173
Q

What is span?

A

Straight line joining one wing tip to another

174
Q

What does increasing the camber on upper surface of aerofoil do?

A

Causes airflow to accelerate more

Generates more lift at same angle of attack

175
Q

What is the point of maximum camber?

A

Distance when camber and chordline is greatest

176
Q

What does the maximum camber determine?

A

High and low speed of aerofoil

177
Q

At low speed, high lift wings, what is the approx max camber point?

A

25%

178
Q

What are laminar flow aerofoils?

A

High cruise aerofoils

179
Q

What is the approx max camber point of laminar flow aerofoils?

A

50%

180
Q

Which coupled moment is stronger, lift-weight or thrust-drag?

A

Lift-weight

181
Q

What force balances couples moments?

A

Horizontal stabiliser force

182
Q

While total pressure remains unchanged, what happens to local static when fluid velocity increases?

A

Local static decreases

183
Q

What happens in straight and level flight (approx 2 degrees AoA)

A

Airflow is streamlined
Transition point and separation point well aft
Airspeed produces most of the lift

184
Q

What happens during a climb? (approx 6 degrees AoA)

A 
Increased lift due to AoA
Decreased lift due to airspeed
Transition point and separation point move forward on wing
Centre of pressure moves forward on wing
Controllability decreases
185
Q

What happens at the stall angle? (16 degrees AoA)

A

More lift due to AoA
Less lift due to airspeed
Airflow over wings is turbulent
Transition point and separation point move forward
Centre of pressure is at forward limit on wing

186
Q

What happens past the stall angle? (>16 degrees AoA)

A

Aerofoil still creating some lift however insufficient to sustain weight
Flow over aerofoil is turbulent
Centre of pressure moves rearwards, increased pitch couple leads to nose drop
Control buffet

187
Q

Why is there a tendency to over bank in climb?

A

Higher airspeed and increased AoA on outer wing creates more lift than inner wing

188
Q

How to you counter tendency to over bank in climb?

A

Hold off bank

Use opposite aileron when established in turn

189
Q

Why is there a tendency to under bank during descent?

A

Outer wing travels greater distance while inner has greater AoA

190
Q

What is adverse aileron yaw?

A

Tendency to yaw out of turn

191
Q

What is the cause of adverse aileron yaw?

A

Increased induced drag on down going aileron

192
Q

How do you minimise adverse aileron yaw?

A

Frise ailerons
Differential ailerons
Coupling the rudder

193
Q

What is coupling the rudder?

A

As ailerons deflected, rudder automatically moves to counteract adverse yaw

194
Q

Which wing stalls first in a spin, up or down going wing and why?

A

Down going wing.

Down going wing generates more drag due to turbulent airflow

195
Q

In a spin, why is there yaw and roll?

A

Yaw due to drag

Roll due to lift and secondary effect of yaw

196
Q

What are the indicators of flat spin?

A 
Higher nose
Increased drag
Decreased rate of descent
Harder to recover
Aft Centre of gravity
197
Q

What are the indicators of steep spin?

A

Lower Nose
Increased rate of descent
Forward Centre of gravity (may result in spiral dive)

198
Q

What are the main differences between a spin and a spiral dive?

A

Spin, low airspeed (stalled)

Spiral dive, high and increasing airspeed (not stalled)

199
Q

What is the effect of using ailerons in a stall?

A

If aileron goes down, AoA increases further, stalling the wing further and results in spin

200
Q

What does indicated airspeed relate to?

A

Lift and drag

201
Q

What is calibrated airspeed?

A

Indicated airspeed corrected for pressure and instrument error
CAS=IAS + IE+PE

202
Q

What is equivalent airspeed?

A

Calibrated airspeed corrected for compressibility error

203
Q

Which is always larger, CAS or EAS?

A

CAS always greater than EAS

204
Q

What happens when air particles are compressed closer together?

A

Gives higher total pressure

ASI over reads

205
Q

What is true airspeed?

A

Equivalent airspeed (EAS) corrected for density error

206
Q

Why is TAS important?

A

Used for navigation purposes

Measures actual speed through the air

207
Q

During a constant 30 degree turn, what will a slower speed do to radius of turn?

A

Smaller radius

208
Q

During a constant 30 degree turn, what will a faster speed do to radius of turn?

A

Larger radius

209
Q

If flying at a given IAS at a higher altitude with low airspeed, what will the TAS and radius of turn be at higher altitude compared to lower altitude?

A

TAS and radius of turn will be greater at higher altitude

210
Q

In order to fly at a turn of same radius at a higher speed, what must you do to angle of bank?

A

Increase angle of bank

211
Q

At a constant airspeed, what will a larger angle of bank do to the radius and rate of turn?

A

Smaller radius, increased rate of turn

212
Q

What is a rate 1 turn?

A

3 degrees/second
180 degrees/min
360 degrees in two mins

213
Q

What does a standard rate of turn at higher airspeed require?

A

Steeper bank angle

214
Q

What is the formula for Angle of bank required for rate 1 turn?

A

10% airspeed + 7

215
Q

What does increase weight do to radius and rate of turn?

A

Increase lift = increase TAS = increase radius and decrease rate

216
Q

What does increasing the altitude do to radius and rate of turn?

A

Decrease density = increased TAS = increased radius and decrease rate of turn

217
Q

What does increasing the TAS do to radius and rate of turn?

A

Increase radius and decrease rate

218
Q

What does decreasing the TAS do to radius and rate of turn?

A

Decrease the radius and increase the rate of turn

219
Q

What affect to radius does doubling the TAS do?

A

4 x radius

220
Q

What does increasing angle of bank have on radius and rate of turn?

A

Decrease radius and increase rate of turn

221
Q

What does decrease angle of bank have on radius and rate of turn?

A

Increase the radius and decrease the rate of turn

222
Q

What is maximum range?

A

Speed which produces minimum drag
Least fuel for greatest distance
TAS for minimum total drag

223
Q

What affect does increased headwind have on glide distance, AOD and rate of descent?

A

Decrease glide distance
Increase angle of descent
Rate is unchanged

224
Q

What affect does increased tailwind have on glide distance, AoD and rate of descent?

A

Increase glide distance
Decrease angle of descent
Rate is unchanged

225
Q

What affect does a heavier aircraft have on range and rate of descent?

A

Same glide range

Increase rate of descent

226
Q

What is maximum endurance?

A

Operating engine at minimum fuel flow
Greatest time from available fuel
TAS where power is minimum and therefore fuel consumption is minimum

227
Q

What affect does a lighter aircraft have on power, fuel flow, range and endurance?

A

Requires less power
Less fuel flow
Increase range
Increase endurance

228
Q

What affect does headwind have on max endurance range and endurance?

A

Decrease range

No change to endurance

229
Q

What affect does tailwind have on max endurance range and endurance?

A

Increase range

No change to endurance

230
Q

What is the region of reverse command and when does it occur?

A

More power required to prevent continuous drop in speed.

Occurs when flying speeds lower than max endurance speed

231
Q

Longitudinal stability is about which axis?

A

Lateral axis (pitch)

232
Q

What will a large tail plane which is a long way from the centre of gravity do to longitudinal stability?

A

Be a large stable moment

233
Q

What does a forward centre of gravity do to longitudinal stability?

A

Increases stability

234
Q

Lateral stability is about which axis?

A

Longitudinal axis

235
Q

What does dihedral, high wing low centre of gravity aircraft do to stability?

A

Increases lateral stability

236
Q

What affect does anhedral wings have on stability?

A

Decreases lateral stability

237
Q

What affect does sweep back wings have on stability?

A

Increases lateral stability

238
Q

Directional stability is about which axis?

A

Normal axis (yaw)

239
Q

What is the restoring force for directional stability?

A

Large keel surface aft of centre of gravity

240
Q

If there is a wing drop, why can there be a spiral dive?

A

Lateral stability attempts to roll level, directional stability attempts to yaw in direction of airflow.
Lateral stability is weaker than directional

241
Q

What is the purpose of trim tabs?

A

To reduce moment of hinge line of control surface to zero ‘hands off’

242
Q

What is a horn balance tab and what does it do?

A

Protrudes into airflow opposite side of control surface deflection, gives some resistance to control surface

243
Q

What is the automatic balance tab and what does it do?

A

Moves automatically to assist control deflection. Moves opposite direction to control surface

244
Q

What is the anti balance tab and what does it do?

A

Moves same direction as control surface and resists control surface movement

245
Q

What is the mass balance and what does it do?

A

Reduces flutter by moving centre of gravity closer to hinge line

246
Q

When taxiing into a headwind, what should you do with the control column?

A

Column neutral or back

247
Q

When taxiing with a tailwind, what should you do with the control column?

A

Column forward

248
Q

With a crosswind from in-front and the left, what should you do with control column?

A

Column back and to the left (aileron up)

249
Q

With a crosswind from behind and the left, what should you do with the control column?

A

Column forward and to the right (aileron down)

250
Q

What type of aircraft does ground looping affect?

A

Tailwheel aircraft

251
Q

What is ground looping?

A

If tail wheel swings left or right unchecked, cannot be stopped with rudder application

252
Q

What is the slipstream effect?

A

Yawing of aircraft to the left (clockwise rotating prop)

253
Q

When is the slipstream effect strongest?

A

At high power

During takeoff and climb

254
Q

What is propeller torque effect?

A

Prop rotates clockwise (right), torque tries to twist engine and airframe anticlockwise (left). Down force presses left wheel hard and cause nose to swing to the left

255
Q

When does the propeller torque affect aircraft?

A

Ground run and climb

256
Q

What is the gyroscopic effect?

A

Torque applied to rotating applied to rotating prop nose down.
Nose down torque applied to top of rotating prop disc applied 90 degrees in direction of prop direction

257
Q

What does the gyroscopic effect direction depends on what?

A

Direction of prop rotation

258
Q

The amount of gyroscopic effect depends on what?

A

Mass of blades
Speed of rotation (RPM)
Rate at which tail is lifted

259
Q

What is the P factor?

A

Down going prop travels greater distance and therefore has a greater AoA and faster than up going blade

260
Q

What happens to P factor as tail is raised?

A

P factor becomes insignificant

261
Q

When is P factor strongest?

A

High power
High AoA
Low airspeed

262
Q

Which of the following would cause aircraft with anticlockwise spinning prop to yaw to the left?

(a) Slipstream
(b) Left flat tyre
(c) Gyroscopic effect
(d) Torque effect

A

(b) Left flat tyre

263
Q

What affect will a larger angle of attack have on wake turbulence?

A

Greater wake turbulence

264
Q

What affect will large aspect ratio wings have on wingtip vortices?

A

Weaker wingtip vortices

265
Q

What does large wingtip vortices produce?

A

Strong rolling moment (wake turbulence)

266
Q

What does decreasing the IAS do to wake turbulence?

A

Increase wake turbulence

267
Q

What does increasing the IAS do to wake turbulence?

A

Decrease wake turbulence

268
Q

What does increasing the weight do to wake turbulence?

A

Increase wake turbulence

269
Q

What does decreasing the weight do to wake turbulence?

A

Decrease wake turbulence

270
Q

What does increasing aspect ratio do to wake turbulence?

A

Decrease wake turbulence

271
Q

When are wingtip vortices strongest?

A

When aircraft is heavy, slow and with gear and flaps up

272
Q

When flying behind an aircraft producing wake turbulence, where should you fly to avoid it?

A

Upwind and above flightpath

273
Q

When taking off behind an aircraft that has just departed, where should you fly to avoid wake turbulence?

A

Before its point of rotation and above its flight path

274
Q

When taking off behind an aircraft that has just landed, where should you fly to avoid wake turbulence?

A

Take off well beyond touch down point

275
Q

When landing behind an aircraft, where should you fly to avoid its wake turbulence?

A

Fly above its approach and land well beyond its touchdown point

276
Q

When landing behind an aircraft that is taking off, where should you fly/land to avoid its wake turbulence?

A

Well before it’s point of rotation

277
Q

When landing on a crossing runway, where should you fly/land behind an aircraft that has touched down on crossing runway?

A

Cross above landing aircraft flight path and touch down beyond runway it has landed on

278
Q

When landing on a crossing runway, where should you fly/land behind an aircraft that is taking off on crossing runway beyond intersection?

A

Touch down before intersection

279
Q

When landing on a crossing runway, where should you fly/land behind an aircraft that is taking off on crossing runway before intersection?

A

Discontinue approach unless landing run can be completed before intersection

280
Q

What heights above and below should you fly to avoid wake turbulence?

A

200 ft above and 1000 feet below

281
Q

What distance approximately is helicopter wake turbulence a problem?

A

3 times the rotor diameter

282
Q

What is stronger, wake turbulence from fixed wing or helicopter of same weight?

A

Helicopter

283
Q

What is thrust stream turbulence?

A

High velocity air from jet or slipstream from prop

284
Q

30 metres behind a jet, what speed approx can you feel at idle and full power?

A

25 kts at idle

125 kts full power

285
Q

Behind a medium and large jet, what distance can you feel thrust stream turbulence?

A

200m behind medium jet

600m behind large jet

286
Q

What speeds can an aircraft fly when in affect of ground effect?

A

Can fly slower than a/c at altitude

Can fly at same speed using less thrust

287
Q

When will you be in effect of ground effect?

A

One wing span of ground, the closer you get the stronger the ground effect

288
Q

What does ground effect do to lift, AoA and induced drag?

A

Greater amount of lift at same AoA and reduction of induced drag

289
Q

Why is there a floating sensation during landing?

A

Because of extra lift and reduction in drag from ground effect

290
Q

As you climb out of ground effect, what happens to coefficient of lift, induced drag and climb performance?

A

Coefficient of lift decreases
Induced drag increases
Climb performance decreases

291
Q

As ice forms on the wings of an aircraft, what happens to stall speed and stall angle?

A

Stall speed increases

Stall angle decreases

292
Q

An aircraft is in straight and level flight at constant power. As weight reduces with fuel burn off, level flight may be maintained by doing what to IAS and nose position?

A

Increasing IAS

Lowering nose

293
Q

An aircraft is maintaining straight and level flight at max endurance speed. What power will be required if speed is to be higher or lower?

A

More power

294
Q

The speed which produces maximum rate of climb for a given weight and power is?

A

The speed at which maximum surplus power is available over and above that which is required for level flight at that speed

295
Q

The effect of increased weight on gliding range of aircraft if AoA is kept constant?

A

Gliding range is not affected

296
Q

What affect will increasing the load factor have on the stall speed?

A

Increase stall speed

297
Q

Climbing an aircraft at a higher speed than recommended for best rate of climb will do what to rate and angle of climb?

A

Decrease rate and angle of climb

298
Q

An aerofoil is said to be at its stalling angle if any increase or decrease in AoA causes?

A

Less lift

299
Q

How will lift and drag vary if AoA is increased from 4 degrees up to stalling angle?

A

Lift and drag will both increase

300
Q

How will lift and drag vary if AoA is increased fro 4 degrees up to stall angle at constant indicated airspeed?

A

Lift and drag will both increase

301
Q

If indicated air speed is kept constant and AoA is increased, what happens to induced and parasite drag?

A

Both will increase

302
Q

What does a decrease in IAS do to control movement and effectiveness?

A

Less resistance to control movement and reduced control effectiveness

303
Q

As indicated airspeed is increased from stalling speed to maximum level flight cruising speed, what happens to induced drag?

A

Decreases continuously

304
Q

During pulling out from a dive, the stall compared to level flight will occur at what IAS and AoA?

A

Higher IAS

Same AoA

305
Q

The IAS which produces the ax rate of climb in piston engine changes as height increases, why is this necessary?

A

Maintain maximum surplus power

306
Q

What will a turn during climb from upwind to downwind do to angle of climb?

A

Decrease angle of climb

307
Q

What will extension of flap during a glide at constant IAS do to rate and angle of descent?

A

Both rate and angle will decrease

308
Q

A heavy and light aircraft of same type are gliding into a headwind at the same lift/drag ratio, the effect on gliding range will be?

A

Heavier aircraft will glide further

309
Q

More power is required during a level turn to maintain the same IAS as in straight and level flight because?

A

Total drag on aircraft is increased during turn

310
Q

The initial effect of prop torque is to cause what?

A

Roll opposite to prop rotation

311
Q

The tendency to yaw on take off in tail wheel aircraft with clockwise prop is greatest when?

A

Crosswind from left

312
Q

When is ground effect most pronounced?

A

Immediately after takeoff

313
Q

The stalling angle of attack of an aerofoil is that angle which?

A

Aerofoil is producing max lift

314
Q

An aircraft is flying at 120kts in straight and level flight. In order to execute a steep turn at same height and IAS, extra power is required to offset what?

A

Increased induced drag cause by higher angle of attack

CPL (11 decks)

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