Aerodynamics Flashcards
0
Q
What is camber?
A
Curvature
Distance between mean camber line and chord line
1
Q
What is the centre of gravity?
A
Weight of aircraft and point which balances can be found.
Acts towards centre of earth
2
Q
What is mean camber line?
A
Line drawn halfway between upper and lower surfaces
Aka averse curvature
3
Q
What is chord line?
A
Straight line joining leading edge and trailing edge of aerofoil
4
Q
Where does lift act?
A
At right angles/perpendicular to relative airflow
5
Q
Where does drag act?
A
Parallel to the relative airflow and opposing motion
6
Q
What is the angle of attack?
A
Angle between the chord line and relative airflow
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
8
Q
What happens as angle of attack increases?
A
Lifting of wing increases
Centre of pressure moves forward
9
Q
What is the primary effects of flaps?
A
Additional lift at slower speed
Increase drag
Shallower climbs
10
Q
What is induced drag?
A
Drag forces associated with production of lift
Related to angle of attack, higher AoA, higher induced drag
11
Q
What is parasite drag?
A
Not associated with development of lift
Higher the speed higher the drag
12
Q
How is induced drag reduced?
A
Reducing span wise airflow
Fitting fences
Winglets
High aspect ratio
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
14
Q
What are the benefits of washout?
A
Less severe wingtip vortices
Less induced drag
Less bending load on wing root
15
Q
How close do you have to be to be in ground effect?
A
Approximately 1 wingspan
16
Q
At 30 bank, what is the load factor and stalling speed?
A
Load 1.5
Stalling speed increased by 7%
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%
18
Q
What is the tendency of bank during climb?
A
Over bank in climb
19
Q
What is the angle of incidence?
A
Angle between chord line of wing and longitudinal axis of plane
20
Q
Where does lift act?
A
Centre of pressure
Right angle/perpendicular to relative airflow
21
Q
What does dihedral wings do to stability?
A
Increases lateral stability
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
23
Q
What is the formula for wing loading?
A
Weight of aircraft/wing area
Kg/m squared
24
What is the boundary layer?
Airflow nearest to the surface of the Aerofoil
25
What is laminar flow?
Smooth airflow
26
What is the transition point?
Airflow within the laminar boundary later that becomes turbulent
27
What is turbulent flow?
Molecules of air not following a streamlined flow pattern.
| This increases drag
28
What is the separation point?
Point at which boundary layer separates from surface of Aerofoil, causing main airflow to break away
29
What happens as you increase velocity?
Decreased static power
30
What does increasing camber of wing do?
Generate more lift at same angle of attack
31
Why is larger camber beneficial?
Good lift, suitable for low speeds and carrying heavy loads
32
What happens as AoA increase?
Lifting ability of winged increases
Centre if pressure moves forward
Airspeed decreases
33
What must happen in the TAS decreases to maintain straight and level?
AoA must increase to compensate
34
What does sharper leading edge and reduce camber do?
Less lift at higher AoA
| Airflow separates more suddenly
35
What are slats?
Short chord aerofoil surfaces attached and extended along leading edge of wing
36
What are the benefits of laminar flow wing?
Higher cruise speeds
Lower fuel consumption
Greater range
37
What do slats provide?
Rounder leading edge
| Increased lift at higher angle of attack and higher nose
38
What are leading edge flaps and what do they do?
Extend from leading edge to change curvature. Allows controlled flow and flight at higher angles of attack
39
What do flaps do?
Increase lift for same AoA
Increase drag
Decrease L/D ratio
Stalling angle is less
For takeoff, increased lift and stalling speed lower
40
What is induced drag?
Associated with production of lift
| Related to AoA
41
What happens to skin friction drag as airspeed increases?
Increases
42
When are the strongest wing tip vortices?
When producing high amounts of lift
43
What are high aspect ratio wings and what do they do?
Long and narrow wings.
Weaker vortices
Less downwash and therefore less induced drag
Lower critical AoA but higher coefficient of lift
Harder to build
44
What is the aspect ratio for rectangle wings?
Span/chord
45
What is the aspect ratio for tapered wings?
Span squared / wing area
46
What is washout?
Inbuilt twist at wing route
47
What are the benefits of washout?
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
48
What factors increase induced drag?
High AoA
| Increase lift production requirement (steep turns)
49
What solutions are the for the ground effect?
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
50
What type of drag is mainly at slow speed?
Induced
51
What type of drag is mainly at fast speeds
Parasite
52
At a constant weight what happens if the AoA is increased?
Required lift can be generated at lower speed
53
In straight and level, if weight is decreased what happens to lift?
Lift produced done at lower AoA which increases speed
| Same IAS occurs at slightly lower AoA
54
What happens to AoA and IAS as we gain height?
Same weight and lift requirements
| Same AoA and IAS. Increased TAS
55
What does a small prop on a big engine do?
Limits thrust to be obtained
56
What effect does a big prop on a small engine do?
Consumes available torque just to rotate
57
What is geometric pitch and is it effective?
When prop is moving forward
Prop is at 0 AoA
Not effective
58
What is the most effective AoA?
4 degrees
59
What is the best blade angle in comparison to blade length from hub?
75%
60
What is windmilling?
When prop drives the engine
Flattens pitch
CTM = ATM
61
What would be the best pitch for high rpm?
Fine pitch
62
What is the best pitch for low rpm?
Coarse pitch
63
The prop rotating clockwise (from cockpit) will push the tail to the right and yaw nose to the left. What is this?
Slipstream effect
64
What are the forces when a plane is in balance?
Total forces are in equilibrium
65
What is the balance point called?
Fulcrum
66
What are static forces?
Forces that act all the time (eg weight)
67
What are dynamic forces?
Forces caused by movement through the air (eg lift)
68
What causes lift and where does it act?
Caused by different static pressures at right angles to airflow
Total lifting forces act through centre of pressure
69
Where does weight act?
Acts vertically down through centre of gravity
70
Where does drag act?
Parallel to relative airflow
71
What happens if centre of pressure (lift) is behind the centre of gravity (weight)?
Nose will go down
72
What happens if the lift (centre of pressure) is forward of the weight?
Nose will go up
73
What happens if drag is above the thrust line?
Nose will go up
74
What happens is drag is below thrust line?
Nose will go down
75
What is the main affect of the tail plane?
Counteracts residual pitching moments
76
What is a fixed tab?
Small metal tab bent into set position
77
What is a trim tab?
Designed to remove stick force for set AoA and power
| Reduces column control surface to zero, allows hands off
78
What is static stability?
Tendency of aircraft to return to original position after being disturbed
If it tends to return, statically stable
79
What is dynamic stability?
```
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
```
80
What is controllability?
Ease at which pilot can manoeuvre aircraft to overcome stability
81
What is the effect of increased stability?
Decreased controllability
82
What is stability around the longitudinal axis?
Lateral stability (aileron/roll)
83
What is stability around the lateral axis?
Longitudinal stability (pitch/elevator)
84
What is stability around the normal axis?
Directional stability (rudder/yaw)
85
What is angular motion?
Rotation around the point/axis
86
What is angular displacement?
Number of degrees of rotation
87
What is Angular velocity?
Speed at which angular displacement occurs
88
What will a forward centre of gravity do to stability?
Increase longitudinal stability
Greater the moment arm for tail place
Greater turning effect of tail
89
How can you increase directional stability?
Bigger fin area and keel surface behind the centre of gravity
90
How can you increase lateral stability?
```
Dihedral wings (up)
Causes lower wing to produced increased amounts of lift
```
91
What occurs if lateral stability is weaker than directional stability?
Spiral instability
92
What happens if lateral stability is stronger than directional stability?
Dutch roll
| Not turn in direction of slipstream
93
Where must the centre of gravity lie on the ground?
Between the wheels
94
If an aircraft is in a displaced yaw (sideslip), what will lateral stability cause?
Increased lift on forward wing
| Decreased lift on trailing wing to roll out of sideslip
95
What is a stabilator?
All moving tail
96
Down going aileron is on which wing?
Up going wing
97
Up going aileron is on which wing?
Down going wing
98
What does the down going aileron cause?
Increased camber of wing
Increased AoA on wing
Increased lift and drag
99
What does the up going aileron cause?
Decreased camber of wing
Decrease AoA
Decreased lift and drag
100
When is adverse aileron yaw most likely to occur?
At slow speeds
101
What do differential ailerons do?
Up going aileron goes higher than down going aileron
| Increased drag on up aileron/down wing
102
What will increase the effectiveness of the rudder?
Increased speed
| Increase slipstream over rudder
103
What do Frise ailerons do?
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
104
What are the primary effects of spoilers?
Increase drag and spoils lift
| Increases rolling moment
105
Where are mass balances placed?
Forward of hinge line
106
What are balance tabs?
On elevator
| Goes opposite direction of rudder to reduce control load
107
What is anti balance tab?
Goes same direction as elevator but higher
Increased stick force
Decreased over stressing structure
108
In straight and level flight, if airspeed reduces, what happens to lift?
Increases
109
What angle of attack is required for straight and level at slow speed?
High angle of attack
110
At high speed, what angle of attack is required?
Low angle of attack
111
What happens to angle of attack and speed as weight is reduced?
Airspeed must reduce
| Angle of attack must reduce
112
What is required to overcome parasite drag?
High speed
Low AoA
Low induced drag
113
What thrust is required at low speeds to overcome induced drag?
High thrust
114
Which is faster, max range speed or max endurance?
Max range speed
115
What is maximum range speed?
Greatest distance for least fuel consumer
Time doesn't matter
Approximately 20% slower than cruise
116
What is maximum endurance speed?
```
Greatest time for available fuel
Distance doesn't matter
Power at minimum
Fly as low as possible
Similar to best rate of climb
```
117
What is speed stable?
Above minimum drag
Any minor speed fluctuation is self correcting
Increased speed = increased parasite drag, causing aircraft to slow
118
What is speed unstable?
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
119
What is a zoom?
Exchanging speed for height
| Temporary
120
What is the absolute ceiling?
Reduction in thrust due to increased altitude, reducing climb to zero
121
What is a climb?
Aircraft driven by excess thrust and sustains speed
122
What is the service ceiling?
When max rate of climb is reduced to 100 feet per minute
123
In a climb, what must the engines thrust overcome?
Drag at climb airspeed
| Component of weight that acts negatively to climb path
124
What are the forces in a climb?
Thrust is greater than drag
Lift is less than weight
No acceleration
125
What happens to the angle of climb if the weight is reduced in max angle of climb?
Greater the angle of climb
126
What happens to the angle if there is greater thrust in max angle of climb?
Greater angle of climb
127
If there is less drag, what happens to the max angle of climb?
Greater angle of climb
128
What is the max rate of climb close to?
Best lift drag ratio
129
What happens if there is excess power in max rate of climb?
Greater the rate of climb
130
What happens if there is less weight in max rate of climb?
Greater the rate of climb
131
What happens if there is less drag in max rate of climb?
Greater the rate of climb
132
What happens to angle of climb and rate of climb in headwind?
Rate stays the same
| Angle of climb steeper
133
What happens to the angle and rate of climb in a tailwind?
Angle shallows, rate remains the same
134
What happens if you increase or decrease the speed in a glide?
Steeper glide
135
What will coarsening the pitch in a glide?
Improve the glide
136
What happens if you reduce the weight in a glide?
Lift will be less so to maintain same angle of attack, must reduce airspeed
137
What happens to time and distance with a headwind?
Time will be same
Reduces glide distance
Steeper
138
What happens with time and distance with a tailwind in a glide?
Time will be the same
Increases glide distance
Shallower
139
What is the load factor formula?
1 / cos bank angle
140
In a level turn with 30 degrees bank, what is the load factor and stall speed?
1.15
| Stall speed increase by 7%
141
In a level turn, what is the go with lift and angle of attack?
Lift is greater
Angle of attack increased
Steeper the turn, greater the lift required
142
In a 60 degrees bank, what happens to load and stall speed?
Load 2
| Stall speed increase by 41%
143
In a 45 degrees turn, what happens to load and stall speed?
Load is 1.41
| Stall speed 19% faster
144
In a 75 degree turn, what happens to load and stall speed?
Load is 4
| Stall speed increase by 100%
145
What is the bank tendency in a level climbing turn?
Tendency to over bank
| Outer wing travels faster than inner, generating more lift
146
What is the tendency of bank in descending turns?
Tendency to underbank in descending turns
| Inner wing travels smaller horizontal distance for same height loss, produces more lift
147
What does and increased angle of bank do to rate and radius of turn?
Increased rate of turn
| Decreased radius of turn
148
What is the formula for a rate one turn?
(Airspeed / 10) + 7 = bank degrees for rate one turn
149
What should you do if there if a headwind from your left on the ground?
Left aileron up
| Tail up
150
What should you do if there is a tail wind from the left?
Left aileron down
| Tail down
151
What does a headwind do to take off distance?
Reduces take off distance
| No change to time
152
What does ice on the wings do to stall speed?
Increases the stall speed
153
What does a headwind do to approach?
Causes steeper approach
154
What does windshear do to airspeed?
Decreases airspeed
155
What will cause you to undershoot on approach?
Tail winds
Decreasing headwind
Downdraft
156
What will cause you to overshoot on approach?
Headwinds
Decreasing tailwind
Updraft
157
What motion will wake turbulence cause to other aircraft?
Strong rolling moment or downdraft
158
When is wake turbulence caused?
During take off of slow heavy aircraft with flaps up
159
How long and far is wake turbulence around for?
Descends 400/500 ft per minute and levels off at 900-1000
| Can persist for up to 3 mins
160
What will a light cross wind do to wake turbulence?
Move upwind vortex across the centre of runway
161
What should you do to avoid wake turbulence?
Fly above and upwind of flight path
| Touchdown beyond heavy aircrafts touchdown point
162
What is thrust stream turbulence?
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
What happens to coefficient of lift as angle of attack increase?
Increase
164
What happens at the critical angle of attack or stalling angle?
```
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
What happens beyond critical angle?
```
Separation point moves well forward
Big increase in turbulence over wing
Increased drag
Decreased lift
Centre of pressure moves back
```
166
What happens to the stall speed as you decrease weight?
Stall speed decreases
167
When will the stall horn go off?
About 5-7 knots before stall
168
What happens in a spin?
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
How is the rate of turn and how many feet do you lose per turn?
Turn every 2-3s and lose approximately 300feet per turn
171
What is the recovery for a spin?
```
Close throttle
Opposite rudder
Column forward
Centralise rudder
Recover
```
172
What is relative airflow?
Airflow opposite to direction of path of aircraft
173
What is span?
Straight line joining one wing tip to another
174
What does increasing the camber on upper surface of aerofoil do?
Causes airflow to accelerate more
| Generates more lift at same angle of attack
175
What is the point of maximum camber?
Distance when camber and chordline is greatest
176
What does the maximum camber determine?
High and low speed of aerofoil
177
At low speed, high lift wings, what is the approx max camber point?
25%
178
What are laminar flow aerofoils?
High cruise aerofoils
179
What is the approx max camber point of laminar flow aerofoils?
50%
180
Which coupled moment is stronger, lift-weight or thrust-drag?
Lift-weight
181
What force balances couples moments?
Horizontal stabiliser force
182
While total pressure remains unchanged, what happens to local static when fluid velocity increases?
Local static decreases
183
What happens in straight and level flight (approx 2 degrees AoA)
Airflow is streamlined
Transition point and separation point well aft
Airspeed produces most of the lift
184
What happens during a climb? (approx 6 degrees AoA)
```
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
What happens at the stall angle? (16 degrees AoA)
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
What happens past the stall angle? (>16 degrees AoA)
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
Why is there a tendency to over bank in climb?
Higher airspeed and increased AoA on outer wing creates more lift than inner wing
188
How to you counter tendency to over bank in climb?
Hold off bank
| Use opposite aileron when established in turn
189
Why is there a tendency to under bank during descent?
Outer wing travels greater distance while inner has greater AoA
190
What is adverse aileron yaw?
Tendency to yaw out of turn
191
What is the cause of adverse aileron yaw?
Increased induced drag on down going aileron
192
How do you minimise adverse aileron yaw?
Frise ailerons
Differential ailerons
Coupling the rudder
193
What is coupling the rudder?
As ailerons deflected, rudder automatically moves to counteract adverse yaw
194
Which wing stalls first in a spin, up or down going wing and why?
Down going wing.
| Down going wing generates more drag due to turbulent airflow
195
In a spin, why is there yaw and roll?
Yaw due to drag
| Roll due to lift and secondary effect of yaw
196
What are the indicators of flat spin?
```
Higher nose
Increased drag
Decreased rate of descent
Harder to recover
Aft Centre of gravity
```
197
What are the indicators of steep spin?
Lower Nose
Increased rate of descent
Forward Centre of gravity (may result in spiral dive)
198
What are the main differences between a spin and a spiral dive?
Spin, low airspeed (stalled)
| Spiral dive, high and increasing airspeed (not stalled)
199
What is the effect of using ailerons in a stall?
If aileron goes down, AoA increases further, stalling the wing further and results in spin
200
What does indicated airspeed relate to?
Lift and drag
201
What is calibrated airspeed?
Indicated airspeed corrected for pressure and instrument error
CAS=IAS + IE+PE
202
What is equivalent airspeed?
Calibrated airspeed corrected for compressibility error
203
Which is always larger, CAS or EAS?
CAS always greater than EAS
204
What happens when air particles are compressed closer together?
Gives higher total pressure
| ASI over reads
205
What is true airspeed?
Equivalent airspeed (EAS) corrected for density error
206
Why is TAS important?
Used for navigation purposes
| Measures actual speed through the air
207
During a constant 30 degree turn, what will a slower speed do to radius of turn?
Smaller radius
208
During a constant 30 degree turn, what will a faster speed do to radius of turn?
Larger radius
209
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?
TAS and radius of turn will be greater at higher altitude
210
In order to fly at a turn of same radius at a higher speed, what must you do to angle of bank?
Increase angle of bank
211
At a constant airspeed, what will a larger angle of bank do to the radius and rate of turn?
Smaller radius, increased rate of turn
212
What is a rate 1 turn?
3 degrees/second
180 degrees/min
360 degrees in two mins
213
What does a standard rate of turn at higher airspeed require?
Steeper bank angle
214
What is the formula for Angle of bank required for rate 1 turn?
10% airspeed + 7
215
What does increase weight do to radius and rate of turn?
Increase lift = increase TAS = increase radius and decrease rate
216
What does increasing the altitude do to radius and rate of turn?
Decrease density = increased TAS = increased radius and decrease rate of turn
217
What does increasing the TAS do to radius and rate of turn?
Increase radius and decrease rate
218
What does decreasing the TAS do to radius and rate of turn?
Decrease the radius and increase the rate of turn
219
What affect to radius does doubling the TAS do?
4 x radius
220
What does increasing angle of bank have on radius and rate of turn?
Decrease radius and increase rate of turn
221
What does decrease angle of bank have on radius and rate of turn?
Increase the radius and decrease the rate of turn
222
What is maximum range?
Speed which produces minimum drag
Least fuel for greatest distance
TAS for minimum total drag
223
What affect does increased headwind have on glide distance, AOD and rate of descent?
Decrease glide distance
Increase angle of descent
Rate is unchanged
224
What affect does increased tailwind have on glide distance, AoD and rate of descent?
Increase glide distance
Decrease angle of descent
Rate is unchanged
225
What affect does a heavier aircraft have on range and rate of descent?
Same glide range
| Increase rate of descent
226
What is maximum endurance?
Operating engine at minimum fuel flow
Greatest time from available fuel
TAS where power is minimum and therefore fuel consumption is minimum
227
What affect does a lighter aircraft have on power, fuel flow, range and endurance?
Requires less power
Less fuel flow
Increase range
Increase endurance
228
What affect does headwind have on max endurance range and endurance?
Decrease range
| No change to endurance
229
What affect does tailwind have on max endurance range and endurance?
Increase range
| No change to endurance
230
What is the region of reverse command and when does it occur?
More power required to prevent continuous drop in speed.
| Occurs when flying speeds lower than max endurance speed
231
Longitudinal stability is about which axis?
Lateral axis (pitch)
232
What will a large tail plane which is a long way from the centre of gravity do to longitudinal stability?
Be a large stable moment
233
What does a forward centre of gravity do to longitudinal stability?
Increases stability
234
Lateral stability is about which axis?
Longitudinal axis
235
What does dihedral, high wing low centre of gravity aircraft do to stability?
Increases lateral stability
236
What affect does anhedral wings have on stability?
Decreases lateral stability
237
What affect does sweep back wings have on stability?
Increases lateral stability
238
Directional stability is about which axis?
Normal axis (yaw)
239
What is the restoring force for directional stability?
Large keel surface aft of centre of gravity
240
If there is a wing drop, why can there be a spiral dive?
Lateral stability attempts to roll level, directional stability attempts to yaw in direction of airflow.
Lateral stability is weaker than directional
241
What is the purpose of trim tabs?
To reduce moment of hinge line of control surface to zero 'hands off'
242
What is a horn balance tab and what does it do?
Protrudes into airflow opposite side of control surface deflection, gives some resistance to control surface
243
What is the automatic balance tab and what does it do?
Moves automatically to assist control deflection. Moves opposite direction to control surface
244
What is the anti balance tab and what does it do?
Moves same direction as control surface and resists control surface movement
245
What is the mass balance and what does it do?
Reduces flutter by moving centre of gravity closer to hinge line
246
When taxiing into a headwind, what should you do with the control column?
Column neutral or back
247
When taxiing with a tailwind, what should you do with the control column?
Column forward
248
With a crosswind from in-front and the left, what should you do with control column?
Column back and to the left (aileron up)
249
With a crosswind from behind and the left, what should you do with the control column?
Column forward and to the right (aileron down)
250
What type of aircraft does ground looping affect?
Tailwheel aircraft
251
What is ground looping?
If tail wheel swings left or right unchecked, cannot be stopped with rudder application
252
What is the slipstream effect?
Yawing of aircraft to the left (clockwise rotating prop)
253
When is the slipstream effect strongest?
At high power
| During takeoff and climb
254
What is propeller torque effect?
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
When does the propeller torque affect aircraft?
Ground run and climb
256
What is the gyroscopic effect?
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
What does the gyroscopic effect direction depends on what?
Direction of prop rotation
258
The amount of gyroscopic effect depends on what?
Mass of blades
Speed of rotation (RPM)
Rate at which tail is lifted
259
What is the P factor?
Down going prop travels greater distance and therefore has a greater AoA and faster than up going blade
260
What happens to P factor as tail is raised?
P factor becomes insignificant
261
When is P factor strongest?
High power
High AoA
Low airspeed
262
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
(b) Left flat tyre
263
What affect will a larger angle of attack have on wake turbulence?
Greater wake turbulence
264
What affect will large aspect ratio wings have on wingtip vortices?
Weaker wingtip vortices
265
What does large wingtip vortices produce?
Strong rolling moment (wake turbulence)
266
What does decreasing the IAS do to wake turbulence?
Increase wake turbulence
267
What does increasing the IAS do to wake turbulence?
Decrease wake turbulence
268
What does increasing the weight do to wake turbulence?
Increase wake turbulence
269
What does decreasing the weight do to wake turbulence?
Decrease wake turbulence
270
What does increasing aspect ratio do to wake turbulence?
Decrease wake turbulence
271
When are wingtip vortices strongest?
When aircraft is heavy, slow and with gear and flaps up
272
When flying behind an aircraft producing wake turbulence, where should you fly to avoid it?
Upwind and above flightpath
273
When taking off behind an aircraft that has just departed, where should you fly to avoid wake turbulence?
Before its point of rotation and above its flight path
274
When taking off behind an aircraft that has just landed, where should you fly to avoid wake turbulence?
Take off well beyond touch down point
275
When landing behind an aircraft, where should you fly to avoid its wake turbulence?
Fly above its approach and land well beyond its touchdown point
276
When landing behind an aircraft that is taking off, where should you fly/land to avoid its wake turbulence?
Well before it's point of rotation
277
When landing on a crossing runway, where should you fly/land behind an aircraft that has touched down on crossing runway?
Cross above landing aircraft flight path and touch down beyond runway it has landed on
278
When landing on a crossing runway, where should you fly/land behind an aircraft that is taking off on crossing runway beyond intersection?
Touch down before intersection
279
When landing on a crossing runway, where should you fly/land behind an aircraft that is taking off on crossing runway before intersection?
Discontinue approach unless landing run can be completed before intersection
280
What heights above and below should you fly to avoid wake turbulence?
200 ft above and 1000 feet below
281
What distance approximately is helicopter wake turbulence a problem?
3 times the rotor diameter
282
What is stronger, wake turbulence from fixed wing or helicopter of same weight?
Helicopter
283
What is thrust stream turbulence?
High velocity air from jet or slipstream from prop
284
30 metres behind a jet, what speed approx can you feel at idle and full power?
25 kts at idle
| 125 kts full power
285
Behind a medium and large jet, what distance can you feel thrust stream turbulence?
200m behind medium jet
| 600m behind large jet
286
What speeds can an aircraft fly when in affect of ground effect?
Can fly slower than a/c at altitude
| Can fly at same speed using less thrust
287
When will you be in effect of ground effect?
One wing span of ground, the closer you get the stronger the ground effect
288
What does ground effect do to lift, AoA and induced drag?
Greater amount of lift at same AoA and reduction of induced drag
289
Why is there a floating sensation during landing?
Because of extra lift and reduction in drag from ground effect
290
As you climb out of ground effect, what happens to coefficient of lift, induced drag and climb performance?
Coefficient of lift decreases
Induced drag increases
Climb performance decreases
291
As ice forms on the wings of an aircraft, what happens to stall speed and stall angle?
Stall speed increases
| Stall angle decreases
292
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?
Increasing IAS
| Lowering nose
293
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?
More power
294
The speed which produces maximum rate of climb for a given weight and power is?
The speed at which maximum surplus power is available over and above that which is required for level flight at that speed
295
The effect of increased weight on gliding range of aircraft if AoA is kept constant?
Gliding range is not affected
296
What affect will increasing the load factor have on the stall speed?
Increase stall speed
297
Climbing an aircraft at a higher speed than recommended for best rate of climb will do what to rate and angle of climb?
Decrease rate and angle of climb
298
An aerofoil is said to be at its stalling angle if any increase or decrease in AoA causes?
Less lift
299
How will lift and drag vary if AoA is increased from 4 degrees up to stalling angle?
Lift and drag will both increase
300
How will lift and drag vary if AoA is increased fro 4 degrees up to stall angle at constant indicated airspeed?
Lift and drag will both increase
301
If indicated air speed is kept constant and AoA is increased, what happens to induced and parasite drag?
Both will increase
302
What does a decrease in IAS do to control movement and effectiveness?
Less resistance to control movement and reduced control effectiveness
303
As indicated airspeed is increased from stalling speed to maximum level flight cruising speed, what happens to induced drag?
Decreases continuously
304
During pulling out from a dive, the stall compared to level flight will occur at what IAS and AoA?
Higher IAS
| Same AoA
305
The IAS which produces the ax rate of climb in piston engine changes as height increases, why is this necessary?
Maintain maximum surplus power
306
What will a turn during climb from upwind to downwind do to angle of climb?
Decrease angle of climb
307
What will extension of flap during a glide at constant IAS do to rate and angle of descent?
Both rate and angle will decrease
308
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?
Heavier aircraft will glide further
309
More power is required during a level turn to maintain the same IAS as in straight and level flight because?
Total drag on aircraft is increased during turn
310
The initial effect of prop torque is to cause what?
Roll opposite to prop rotation
311
The tendency to yaw on take off in tail wheel aircraft with clockwise prop is greatest when?
Crosswind from left
312
When is ground effect most pronounced?
Immediately after takeoff
313
The stalling angle of attack of an aerofoil is that angle which?
Aerofoil is producing max lift
314
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?
Increased induced drag cause by higher angle of attack
