Principles of Flight Flashcards
1
Q
The quantity of matter a body possesses
A
Mass
2
Q
The rate of change of velocity
A
Acceleration
3
Q
The rate of change of position of a body in a specified direction
A
Velocity
4
Q
Energy cannot be _____ only _____
A
Destroyed
Transferred
5
Q
1/2MV² =
A
K.E.
6
Q
Force x Distance =
A
Energy
7
Q
Power = Energy/_____
A
Time
8
Q
Power = ____ x Distance / Time
A
Force
9
Q
Energy = ____ x ____
A
Force
Distance
10
Q
Force x Speed =
A
Power
11
Q
Newtons 1st Law:
A
An object will continue at a constant velocity unless acted upon by an unbalanced force
12
Q
Newtons 2nd Law
A
The rate of change of momentum is equal to the force applied. (F =MA)
13
Q
Newtons 3rd Law
A
Every action has an equal and opposite reaction
14
Q
When air temperature increases, the _____ _____ it is.
A
Less Dense
15
Q
The more _____ the air, the less dense it is
A
Humid
16
Q
The _____ the altitude, the less dense it is
A
Higher
17
Q
Air density (ρ) = ____ / Temperature (T)
A
Pressure (P)
18
Q
°C to Kelvin =
A
+273°C
19
Q
Sea level temperature
A
15°C
20
Q
Sea level pressure
A
1013.25HPa
21
Q
Sea level Density
A
1.225kg/m³
22
Q
Lapse rate
A
1.98°C per 1,000ft up to 11km (36,089ft)
23
Q
Temperature above 11km
A
-56.5°C
24
Q
IAS
A
Indicated Airspeed
25
CAS
Calibrated Airspeed
26
EAS
Equivalent Airspeed
27
TAS
True Airspeed
28
Total pressure (Pt) = _____ Pressure + _____ Pressure
Dynamic (q)
| Static (Ps)
29
Dynamic Pressure ~ _____
Indicated Airspeed
30
q or IAS = 1/2ρV² =
q or IAS = 1/2ρTAS²
31
If ρ _____, __ must increase
Decreases
| V²
32
1013.25HPa
Sea level Pressure
33
1.225kg/m³
Sea level Density
34
___ --> Instrument/_____ error --> CAS --> _____ --> EAS --> Density --> ___
_IAS_ --> Instrument/_Pressure_ error --> CAS --> _Compressible_ --> EAS --> Density --> _TAS_
35
IAS --> _____/Pressure error --> ___ --> Compressible --> ___ --> _____ --> TAS
IAS --> _Instrument_/Pressure error --> _CAS_ --> Compressible --> _EAS_ --> _Density_ --> TAS
36
IAS = TAS √(_____/ρ sea level)
ρ current alt.
37
3 types of flow:
Streamline
Turbulent
Vortex
38
The faster the _____. the _____ the stream tube
Molecules
| Thinner
39
Streamlines are
Lamina flow (smooth)
40
Vortex flows require
lots of energy
41
Streamline flows have the least _____ and _____
Energy
| Drag
42
Turbulent flow path lines can _____ and _____
Touch
| Cross
43
Perfect fluid basic assumptions
They are In-compressible
| They have no Viscosity
44
You should factor in air compression at speeds above _____
350 knots
45
Mass can neither be _____ or _____
destroyed
46
AVρ = _____
Mass flow = constant
47
The rate of change of momentum is equal to the force applied. (F =MA)
Newtons 2nd Law
48
Acceleration =
The rate of change of velocity
49
An object will continue at a constant velocity unless acted upon by an unbalanced force
Newtons 1st Law
50
Velocity =
The rate of change of position of a body in a specified direction
51
Mass =
The quantity of matter a body possesses.
52
Every action has an equal and opposite reaction
Newtons 3rd Law
53
1nm = __m
1852m
54
1m = __ft
3.28ft
55
1nm = __ft
6076ft
56
1 inch = __cm
2.54
57
1kg = __Ibs
2.2Ibs
58
m/s = ___ x knots
0.5144 (approx 0.5)
59
knots = ___ x m/s
1.944 (approx 2)
60
The drag effects in 2D are....
Form Drag, and Skin Friction Drag
61
Interference Drag is caused by
Flow hitting a junction and having to change direction
62
Parasite drag is made up of
Form, Skin Friction, and Interference Drags
63
Total Drag is made of Parasite Drag, and....
Induced Drag
64
Parasite drag is ________ to V^2
Proportional
65
Induced Drag is _________ to V^2
Inversely proportional
66
To reduce interference drag, we can create less hard junctions using
Fillets, or Fairings.
67
Skin Friction Drag is affected by.... (4 things)
Speed, Surface Area, Boundary Layer conditions, Type of Surface.
68
Parasite Drag Equation
D = 0.5 Rho V^2 S Cdp
69
A clean air craft will create _________ Parasite Drag
Less
70
A heavy aircraft will create __________ Induced Drad
More
71
Induced Drag equations are.....
ID is inversely proportional to aspect ratio
ID is inversely proportional to IAS^2
ID = 0.5 Rho V^2 S Cpi
72
Coefficient of Induced drag is proportional to
(Coefficient of lift)^2
73
Coefficient of Induced drag is Inversely proportional to
Aspect Ratio
74
As speed is reduced by a half, Cdi increases by a factor of
16
75
Wing tip modifications are used to....
Reduce induced drag, by reducing wing tip vorticies.
76
3 main types of wing tip modification
Winglets, Wing tip Tanks, Tapered Tips
77
Vmd is....
Velocity of Minimum Drag
78
At Vmd....
parasite drag = induced drag
79
Drag _____ to Vmd, then...
Decreases, increases in a non linear fashion
80
On the backside of the speed curve....
V
81
Above the Vmd on the speed curve....
we have Speed stability
82
At the bottom of the speed curve, near to Vmd....
we have Speed Neutral. Little changes in speed will not change drag by much.
83
How does the total drag curve change with IAS?
It does not! Ruler bend is ruler bend, is ruler bend.... whatever that means.
84
When plotting Total Drag against TAS, increasing altitude....
shifts the Total drag curve to the right.
85
When plotting Total Drag against TAS, increasing weight....
shifts the total drag curve to the right, and up. (a sort of pivot effect)
86
When plotting Total Drag against TAS, using flaps etc....
pivots the total drag graph anticlockwise from the end of the nike tick shape
87
Increasing altitude ________ the TAS of Vmd
Increases
88
Increasing weight, ________ the TAS of Vmd
Increases
89
Flaps down, Vmd.....
down.
90
Cd= (2 components)
Cdp + Cdi, or Cdi +k(Cl)^2
91
As L=q S Cl, and D=q S Cd...
L/D = Cl/Cd
92
By plotting Cd against Cl, we create the drag polar graph. the gradient of this graph will give us
Cd/Cl, or L/D
93
Maximum L/D is the _________ Lift
Greatest
94
Vmd is at ________ AoA
4 degrees
95
Min D/L is the __________ lift
Maximum lift
96
Lift to drag ratio of a training aircraft
11:1
97
Lift to drag ratio of a modern air transport plane)
20:1
98
Straight rectangular wings stall at the______ first.
Root
99
Swept wings stall at the _______ first
Wingtip
100
Stalling at the wingroot first is advantages because....
it creates a natural buffer in the tail, warning or an imminent full wing stall.
101
If a swept wing stalls.... (3 things)
Uneven stall could cause wingdrop
CP moves forward and inward
We get a nose-up moment.
102
A deep stall mainly affects
T-tail designed planes
103
A deep stall means that....
the horizontal stabiliser becomes completely immersed in turbulent wake from the stalled wing, that it loses all effectiveness. This is very bad.... and will probably result in a large bang as you hit the ground.
104
To reduce wing tip stalling tendencies in swept wings we need to....
reduce the lateral movement of air over the wing.
105
To reduce the wing tip stalling tendencies of a swept wing, we can install (3 things)....
Vortilon, a Wing Fence, or a Saw Tooth design.
106
A Low-speed cross-sectional wing will have ________ Cl, _________ Clmax and _________ AoA
Greater, Greater, Higher
107
A high-speed Cross-sectional wing will have ________ Cl, _________ Clmax, and __________AoA
Lower, Lower, smaller
108
A Stall Strip.....
Artificially increases the sharpness of a wing, to instigate an early root stall
109
Flaps are a......
Camber changing device
110
Slats .....
Re-energise the boundary layer.
111
Draw the graph of showing how Trailing Edge flaps, Leading edge flaps, and slats/slots affect the Clmax and AoA.
I'm not paying to go pro to add images, so check p327 of the text, or your notes!
112
Using Ailerons close to critical AoA can cause
Adverse Camber Roll, due to stalling of the wingtip.
113
Increasing mass will _________ Stalling Speed
Increase
114
Putting flaps down will _________ stalling speed
Decrease
115
Putting landing gear down will ________ stalling speed
Increase
116
With Power On, stalling speed is...
Slower
117
With Power off, stalling speed is...
Higher
118
Swept wing planes have a _______ Stalling speed
Greater
119
A plane with a further forward CoG will have a _______ stalling speed
Greater,
120
As we increase altitude, what happens to stalling speed?
It remains the same
121
At high altitude, with high TAS above 300kts, what happens to IAS stalling speed?
Stalling speed will increase.
122
Contamination causes the stalling speed to
Increase
123
Manoeuvers cause the stalling speed to....
Increase
124
The load factor in a turn is
1/cos (Phi), where phi is the angle of bank.
125
Vs= Stall Speed at 1g x
Sqrt(Load Factor)
126
Flaps are camber chaning devices. ToF?
True
127
Slats are camber chaning devices. ToF?
False
128
Increasing camber by using trailing edge flaps __________ Cl, ________Clmax, and ________Critical AoA
Increases, Increases, Decreases
129
Slots allow....
high pressure air to travel through the wing, re-energising the boundary layer, delaying the separation point and delaying the stalling AoA.
130
Using Ailerons close to your critical AoA can cause....
the wing to stall, resulting in Adverse Camber roll
131
CS23 requires the Vs to be multiplied by what, to give Vs1 and Vs0
1.2 for Vs1, 1.3 for Vs0
132
CS25 requires the Vs to be multiplied by what, to give Vs1 and Vs0
1.13 for Vsr1, 1.23 for Vsr0
133
For Autorotation to occur....
Both wings must be stalled
134
To recover a stall, we must....
Increase power............just kidding, it's reduce AoA
135
Easa regulations state aircraft must have an ______ stall warning
Audio
136
The Margin for a stall warning system is....
5kts or 5% above a stall, whichever is greater.
137
Aeorodynamic stall warnings
occur naturally for aerodynamic reasons (buffet)
138
Artificial Sall warning systems are,,,
Electro-mechanical sensors that detect a stall
139
At the stall we can expect..... (4 things)
Cl collapse and descent, increased buffet, Nose up or nose down moment, depending on wing shape, wing drop.
140
Stall prevention devices engage at....
2kts, or 2% above stall speed
141
A stick shaker is a stall _______ device
warning
142
A stick pusher is a stall _________ device.
Prevention
143
A forward sweep wing would be better in a stall, however.....
required to be stronger, and therefore hevier.
144
A plane with elevator stabilisers ahead of the wing is called....
Canard
145
The advantage of elevators in front of the wing, is that....
The wing has to produce less lift.
146
A flapper switch uses what to recognise when you are reaching your stalling AoA?
The stagnation point on the leading edge
147
AoA Vanes....
Attach to the side of the fuselage and electronically detect AoA to effective airflow.
148
AoA vanes are more accurately described as....
"Air Direction Detectors"
149
AoA Probes....
Use two slots to identify differing air pressures, thus calculating AoA
150
Rotating probes.....
are Null Seaking, and rotate to balance the air pressure in two tubes, detecting AoA
151
Pitch indicators on deisplays are often called....
eyebrows!
152
Vsw is,,,,
Velocity Stall Warning
153
The R in Vsr is there because...
it is a calculated speed
154
The stalling angle on a swept wing plane is....
less defined
155
With flaps down, the CP
Moves back
156
With a high wing plane, when extending flaps, there is a transitional...
Nose up rotation.
157
Usually, lowering flaps will cause a ______ ______ Rotation
nose down rotation
158
Lowering flaps _______ Downwash
Increases
159
A split flap will do what to Cl and critical AoA
Greater Clmax and AoA than plain flap, but still small AoA than a clean wing. Cl will remain the same for same AoA for a normal flap.
160
A leading edge flap gives.....
More camber
161
A Krueger Flap is found on what make of aircraft?
Boeing
162
A Krueger Flap reduces the.....
Leading Edge Radius, and therefore induces seperation.
163
A Kreuger flap increases the
Camber
164
A leading edge flap that creates a Slot is called a....
Slat.
165
A fowler flap....
Increase surface area and camber.
166
A Fowler flap moves
Aft first, and then down,
167
A Fowler flap will most likely require a
slot, to reenergise the boundary layer.
168
Slots and slats increase
Critical AoA
169
Slats that are fixed......
do not exist. they must move to be a leading edge flap, and therefore a slat.
170
With Flaps down, we have ______wingtip vorticies
Smaller.
171
At landing, flaps will _______ our decent angle.
Steepen
172
Wing tip vortices _____ when flaps are lowered due to less _____.
Decrease
| Downwash
173
Vortex generators produce _____ _____ which _____ the boundary layer. These are placed in front of the _____.
Small vortexes
Increase
Ailerons
174
Usually, the first __% of flap deflection provides more than half the total increase in Cl
50%
175
The second 50% provides more than half of all _____
Drag
176
Complete flap failure requires:
Faster approach at a higher AoA
Longer landing run
Reduced margin above the stall requirement
177
Flap protection system use an _____ to prevent flaps from being lowered until the speed falls below the _____ _____ _____
Interlock
| Flap extension speed
178
What do configuration warning systems do?
Alert the crew to an incorrect flap setting for the particular flight phase
179
What do Flap asymmetry sensors do?
Stop flap operation if they detect that flap is lowering
| asymmetrically
180
The Ram Effect is
The cushioning effect when the pressure below the wing rises because the volume between the ground and the lower surface of the wing reduces, compressing the air flowing underneath.
181
In the ground effect vortices become _____
Compressed
182
In ground effect, the EAF is _____, resulting in a reduced _____ _____ and an increased _____ _____. this means the stalling angle is _____.
Shallower
Induced angle
Effective angle
Reduced
183
The closer to the ground you are, the _____ the effect.
Greater
184
In ground effect, lift is _____, known as _____. and the induced rage is _____.
Increased
Ballooning
Reduced.
185
Entering the ground effect results in a nose _____ moment and leaving it results in a nose _____ moment. This is due to the decreased/increased _____.
Down
Up
Downwash
186
Entering the ground effect will make the IAS _____ _____
Under read
187
The ground effect come into effect _______ from the ground, but is not noticeble until _______ from the ground.
1 wingspan
| 1/2 wingspan
188
Flaps are
Camber changing devices
189
Hinge moment = __________ x __________
Hinge moment = force felt x distance from the hinge
190
An inset hinge is where...
The hinge on the control surface is moved back to reduce the hinge moment.
191
A horn balance is...
an area of control surface in front of the hinge which produces an opposite hinge moment.
192
An internal balance is...
a flexible diaphragm between the trailing edge and the control surface which creates a a force on the control surface to help move it due to pressure difference above and below the wing.
193
A balance tab is...
A tab at the rear of the aircraft that moves in the opposite direction of the control surface to aid it's movement.
194
An anti-balance tab is...
The opposite of a balance tab for when the controls are too easy to move.
It is not an aid.
195
A servo tab is...
Similar to a balance tab, but the control column moves the tab which then as a result moves the control surface.
This is only good a high speed
196
A spring tab is...
Where due to a springs force, if at high speed, the control column will move the tab, and if at low speed, it will move the control surface.
197
Mass balancing is...
where mass is added ahead of the hinge line to prevent flutter.
It is not an aerodynamic balance.
198
Power-assisted controls:
The control column is directly attached to the control surfaces, however hydraulic forces provide most of the source.
199
Fully-powered controls:
The control column is not directly connected to the control surface. It requires an artificial feel system (Q-feel system).
200
The AoA _____ on a down-going wing and _____ on an up-going wing.
Increases
| Reduces
201
A tailplane pitch is normally set to a _____ incidence due to the forward ___
Negative
| CG
202
What type of tailplane is more effective?
The T-tail
203
When the rudder is deflected, the aircraft will _____ and if held it will _____.
Yaw
| Sideslip
204
A rudder travel limiter...
Prevents the rudder being moved to far and breaking off at high speeds.
205
Adverse aileron yaw
There is less drag on the downward wing, and more on the upward wing.
206
Differential Ailerons
The angle of the aileron on the down-going wing is greater than that of the up-going wing
207
Firse Ailerons
The leading edge of the aileron is asymmetrically shaped. when facing upwards it increases the form drag.
208
On large aircraft, at high speeds, the _____ ailerons are locked and the _____ ailerons are used only. _____ _____ are used to aid roll control.
Outbound
Inbound
Flight spoilers
209
Advantages of spoilers:
Don't suffer from flutter
Leave trailing edge free for flaps
Cause no twisting moment
210
Flaperons
The inboard aileron aiding the function of the flaps.
211
Control coupling
Rudder is used when a roll command is made aiding against adverse aileron yaw
212
Spoilers
Disturb the airflow and reduce the Clmax
213
Speed breaks can be used to
Reduce airspeed rapidly
Increase angle of descent
Increase rate of descent
Control the airspeed in a descent
214
Aileron droop
Ailerons can be drooped slightly for take off to compensate for the loss of potential flap area, increasing the camber and lift
215
Rudder primary and secondary effect
Yaw
| Roll
216
Aileron primary and secondary effect
Roll
| Sideslip the yaw
217
Equilibrium
When all 4 forces acting on an aircraft are equal and opposite.
218
Trimmable horizontal stabiliser (THS)
controlled by an electric screw jack which drives the staboliser to a positive or negative AOI.
219
THS are used on modern jet aircraft because:
They are aerodynamically effective
Doesn't reduce effective range of the elevator
Have more force than the elevator
220
It is important to set the THS to the correct incidence before take off because...
An angle to positive can reduce the rate of rotation
| An angle to negative can increase risk of tail strike
221
Load factor = _____/_____
Load factor = lift/weight
222
Thrust acts in the opposite direction to....
Relative air flow
223
Increasing thrust on a conventional airliner results in a _______ pitching moment
Nose-up
224
If wind = 0, the flight path angle and the AoA is _____
The same
225
Angle between the horizontal axis and the aircraft's longitudinal axis.
Pitch angle
226
Angle between the flight path angle and the longitudinal axis
AoA
227
Angle between the horizontal and the flight path
Flight path angle (γ)
228
The more excess thrust...
The greater the climb angle
229
Best angle of climb
The steepest climb angle
230
Best rate of climb
Climbing as quick as possible
231
Excess thrust = _____ x _____
weight x sinγ
232
Lift = _____ x _____
weight x cosγ
233
Climb angle equation
Sinγ = T - D/W
234
The more weight, the _____ the climb angle
Shallower
235
In a steady climb, Weight is _____ than lift. Thrust is _____ than drag
Greater
| Greater
236
For jet aircraft, Vx is the same as _____ at an AoA of _____.
Vmd
| 4°
237
For Jet aircraft at altitude, Vx ___________
Stays the same
238
For prop aircraft, Vx is __________
Close to stall speed
239
For prop aircraft, Vmp is ___ Vmd, where the AoA is _____
0.76
| >4°
240
The flight path _____ with altitude
Reduces
241
% gradient =
(T - D / W) x 100
242
Shallow glide angles are achived with a _____ configuration
Clean
243
Descending at Vmp is a _____ angle, but descends _____
Steeper
| Slower
244
Descending at Vmd is a _____ angle, but a _____ descent
Shallower
| Faster
245
_____ does not effect the glide angle
Weight
246
A tailwind will _____ the glide path, and a headwind will ______ it.
Increase
| Decrease
247
The force that opposes centrifugal force is ________
Centripetal force
248
The horizontal component of lift supports the _______ and the vertical component supports the _____.
Centrifugal force
| Weight
249
What 2 things effect the radius of a turn?
Speed
| Weight
250
Equation for CPF
CPF = M x V²/ r
251
Equation for radius of a turn
r = V² / g x TanΦ
252
Equation for the bank angle
CosΦ = W/L
LF = 1/CosΦ
253
Rate 1 turn:
3° per second, 180° a minute
254
Rate if turn =
(TAS / Radius) x 60
255
If double the airspeed, radious will _____ and the rate of turn will _____.
x4
| 1/2
256
Turn equations only use _____
S.i. units
257
Turn and slip indicator
Indicates rate of turn and the centripetal force Vs centrifugal force.
258
Maximum turning performance is determined by:
Max. lifting capability
Structural strength
Thrust
259
What properties does and ideal liquid have?
Incompressibility, Zero Viscosity
260
In an ideal fluid, the flow pattern that strikes an object and then doesn't flow around it happens at the ______ ______
Stagnation Point
261
Viscosity in a flow pattern creates ______ behind the object
Wake
262
Unbalanced force created by an object in viscosity is called ______ ______
Form Drag
263
Lift to Drag Ratio for Training Aircraft
10:1 - 12:1
264
Lift to Drag Ratio for Long Haul Jets
18:1 - 20:1
265
Lift to Drag Ratios for Gliders
Above 25:1
266
The front of an Aerofoil is called the _____ _______
Leading Edge
267
The rear of an Aerofoil is called the _______ ______
Trailing Edge
268
The horizontal distance between the Leading and Trailing edges is the....
Chord
269
The shortest distance between the Leading Edge and the Trailing Edge is the.....
Chord Line
270
The leading edge radius is.....
The radius of a circle that would create the leading edge.
271
The Thickness of a wing, is the....
Wing thickness, at its thickest point
272
The Camber Line is the....
Imaginary line that bisects the Aerofoil
273
The Camber is....
The distance between the amber line and the surface of the wing.
274
Angle of Attack is.....
The angle between the Chord Line, and the Relative Airflow.
275
The 4 types of Aerofoil are...
Positive Camber
Negative Camber
Symmetrical
Biconvex
276
The two types of Aerofoils we work with in POF are...
Positive Camber
| Symmetrical
277
The Thickness to Chord ratio is also called the ____ of the Aerofoil
Fineness
278
As AoA increases, the Stagnation point.....
Moves further down the leading edge
279
As AoA decreases, that Stagnation point......
Moves further up the leading edge
280
The ________ ______ is the point of greatest static pressure reduction
Suction Peak
281
Aerodynamic Total Reaction is made up of which two forces?
Lift and Drag
282
A sharp trailing edge reduces....
Adverse Pressure Gradient
283
What two actions on a Aerofoil are needed to produce lift?
Upwash, and Downwash
284
Lift is _______ to the free stream flow.
Perpendicular
285
Drag is ________ to the free stream flow.
Parallel
286
Lift acts at the ______ __ _______ of an aerofoil
Centre of Pressure
287
If you double the speed of the airflow over an Aerofoil, you _______ the lift.
Quadruple (x by 4)
288
If you increase the speed of airflow over an Aerofoil, Magnitude ______ and Distribution of forces ______
Magnitude Increases
| Distribution of forces stay the same
289
Changing the angle of attack will ______ magnitude of the forces and the distribution of forces will _______
Increase
| Change
290
When increasing the AoA on a Cambered Aerofoil, the Centre of Pressure will ________
Move closer to the Leading Edge
291
The Centre of Pressure on an aerofoil is roughly how far along the total length?
25%
292
When decreasing the AoA on a Cambered Aerofoil, the Centre of Pressure will ________
Move further from the Leading Edge
293
When increasing the AoA on a Symmetrical Aerofoil, the Centre of Pressure will ________
Remain still
294
When decreasing the AoA on a Symmetrical Aerofoil, the Centre of Pressure will ________
Remain still
295
At 0 degrees AoA, a symmetrical Aerofoil will produce ________ lift
No
296
At 0 degrees AoA, a Cambered Aerofoil will produce ________ lift
Positive or negative lift, depending on its design.
297
To get zero lift on a positively cambered Aerofoil, we need a_______
Negative AoA.
298
Increasing the camber of a wing will...
Increase pressure differential between the upper and lower surfaces.
299
In a cambered Aerofoil, the pressure distribution is affected by ______ and ______
AoA and Camber
300
In Aerodynamic Force, q is
Dynamic Pressure
301
In Aerodynamic Force, S is
Surface area
302
Aerodynamic Force Coefficient is a __________ number/ratio
Dimensionless
303
Our force equation is
F = q*S*CF,
or
F = 0.5 * Rho * V^2 * S * CF
304
Our lift equation is
L = IAS^2 * S * CL
or
F = 0.5 * Rho * V^2 * S * CF
305
To maintain Lift, if IAS goes down....
AoA must go up
306
The Aerodynamic Force Coefficient in Lift is affected by what 3 things?
Angle of Attack
Camber
Thickness
307
In flight, we can change which of the items in out Lift Equation?
Lift
Speed
Angle of Attack (CL)
308
In our lift equation, V, IAS or TAS are given in what units?
m/s
309
In an Aircraft, at what point does lift act?
Centre of Pressure
310
In an Aircraft, at what point does drag act?
Centre of Pressure
311
In an Aircraft, at what point does Weight act?
Centre of gravity
312
In an Aircraft, where does Thrust act?
Through the centre of the engine
313
Engines below the couple created by the Centre of Gravity and Centre of Pressure, create a ______ ______ ______.
Nose up Rotation
314
Which must be further forward in an EASA Aircraft, CoG or CP?
CoG
315
The Critical AoA is the angle at which an Aerofoil...
Produces the Maximum Lift Coefficient.
316
Flying at the Stalling AoA will cause the plane to stall. True or False?
False, exceeding this angle will cause the aircraft to stall
317
At the Critical AoA, we say the Coefficient of Lift is
CLMAX
318
Our standard Stalling AoA on a Symmetrical wing is
16 Degrees
319
Adding thickness does what to the stalling AoA of an Aerofoil?
Increases the Stalling AoA
320
A cambered Aerofoil will have a ________ CLMAX than a symmetrical Aerofoil
Greater
321
Flaps are ______ ________ Devices
Camber Changing
322
As flaps go down, the ______ Increases
Camber
323
As flaps go down, and the Camber increases, what must change to maintain the CL?
AoA must reduce.
324
"Straight and Level means what cannot change?
Lift and IAS
325
Force Coefficient is the ratio of...
Surface Pressure:Dynamic Pressure
326
Form drag
The wake that is formed behind the wing
327
Skin drag
The drag in the boundary layer
328
The drag coefficient gives us a measure of drag per _____ _____ and unit _____ _____
Unit area
| Dynamic pressure
329
Drag is a component of the _____ _____ and governed by the fundamental _____ force
Total reaction
| Aerodynamic
330
The boundary lays
Area extending from the aircraft's surface out to the point where the speed if airflow is 99% of the free stream flow
331
The transition point is where
Laminar flow becomes turbulent flow
332
The laminar layer is only ______ thick, it is _____ and has _____ _____
A few mm
Slippery
Low energy
333
The turbulant layer is _____ thick, it is _____ and has _____ _____
A few cm
Draggy
High energy
334
The separation point is where
The boundary layer separates from the upper surface. of the aerofoil.
335
There is more energy at the _____ of the boundary layer.
Base
336
A low Reynolds no. means (<500,000)
Lamina flow
337
A high Reynolds no. means (>10,000,000)
Turbulent flow
338
The transition point is 1/3 in front of the ______ ______ _____ or 2/3 behind the _____ _____
Point of maximum thickness
| Leading edge
339
In lamina flow, _____ forces are dominant
Viscus
340
In turbulent flow, _____ forces are dominant
Dynamic
341
Aerodynamic drag
The force on an object that resists its motion
342
The more viscous the air
The greater the shearing force
343
All effects if skin friction drag take place within the
Boundary layer
344
The laminar boundary layer has a _____ velocity gradient
Shallow
345
The turbulent boundary layer has a _____ velocity gradient
Steep
346
Nose to tail axis:
Longitudinal - role
347
Wingtip to wingtip axis:
Lateral - pitch
348
Vertically through the fuselage axis:
Normal - yaw
349
Wingspan
The distance between the wingtips
350
Gross wing area
The planform of the wing and the area of fuselage between the wing roots.
351
Wing taper
When the tip is smaller than the root.
352
Taper ratio = _____/_____
Taper ratio= tip chord/root chord
353
Aspect ratio
The ratio of wingspan to average wing chord
354
Aspect ratio = _____/_____
Aspect ratio = Span/average chord
| if highly tapered: Aspect ratio = Span²/wing area
355
Sweep angle
The angle at which the wing is inclined to lateral axis.
356
The more swept back a wing, the higher _____ you can cruse at
Mach no.
357
Mean aerodynamic chord (MAC)
The chord of an imaginary rectangular wing which has similar longitudinal stability properties to the actual wing
358
Angle of incidence
The angle between the chord line of the wing and the aircraft's longitudinal axis.
359
Washout
Reduction the in angle of incidence from the root to the tip.
360
Dihedral and Anhedral angles
The angle of the wings relative to the aircraft's lateral axis.
361
Dihedral can be found on aircraft with wings angling
Upwards (e.g. A320, 737)
362
Anhedral can be found on aircraft with wings angling
Downwards (e.g. BAe 146)
363
Wing planform
The outline shape of a wing when seen from above
364
Wing tip vortices are formed when
Air travels from high pressure under the wing to low pressure above the wing by flowing around the wing tip.
365
Longer chord at the wingtip will result in
Greater vortex
366
Spanwise flow travels from _____ to _____ under the wing and _____ to _____ above the wing
Root to tip
| Tip to root
367
The vortex spins _____ on the left wing and _____ on the right wing
Clockwise
| Anti-clockwise
368
The intensity of the tip vortex depends on what 2 things:
The pressure difference above and below the wing.
| The amount of time the driving force is given to operate on the air mass
369
A _____ _____ can only form when the wing is producing _____
Wing vortex
| Lift
370
Tip vortices _____ with increasing _____ _____
Decrease
| Forward speed
371
A low aspect ratio wing produces _____ _____ tip vortices than a high aspect wing ratio.
More intense
372
Trailing edge vortices ten to be weaker at the _____ of the wing.
Root
373
In 2D flow, the upwash and downwash are _____ in magnitude
Equal
374
In 3D flow, the upwash _____ and the amount of downwash _____.
Decreases
| Increases
375
Downwash is greater at the _____ _____
Wing tip
376
Effective airflow
The combination of both horizontal and vertical velocities
377
The effective airflow determines the wings _____ _____
Aerodynamic forces
378
The component of aerodynamic force acting at ___ to the flow must be shown acting 90° to the _____ _____
90°
| Effective flow
379
The angle between the Relative airflow and Effective airflow is called:
The induced angle of attack
380
Anything the effects the amount of downwash is going to ____ the effective airflow.
Steepen
381
The Component of the vector parallel to the relative airflow
Induced Drag
382
Induced drag always accompanies the production of _____
Lift
383
If the induced angle of attack increases, induced drag _____
Increases
384
The angle of attack is the angle between the aircraft's _____ _____ and the _____ _____
Longitudinal axis
| Relative airflow
385
The induced angle of attack the is angle between the _____ and _____ air flows
Effective
| Relative
386
The induced angle of attack is larger when (2 things):
The aircraft is flying at a lower TAS
and/or
The vortices are stronger there for producing greater downwash.
387
The effective angle of attack is the angle between the _____ _____ and the _____ _____ of the wing
Effective airflow
| Chord line
388
Small vortices result in _____ effective airflow angle, meaning a _____ effective angle of attack and a _____ induced angle of attack
Shallower
Larger
Smaller
389
The effective airflow angle will be _____ at the wing root and _____ at the wing tip.
Shallower
| Steeper
390
The higher the aspect ratio, the _____ the lateral pressure gradient.
Smaller
391
3 Disadvantages to a high aspect wing:
Needs a stronger, heavier main spar to support the larger wing.
More prone to tip strikes during take-off and landing.
At higher speeds, induced drag is a small percentage of the total drag, so the aerodynamic advantages are less significant.
392
For a given _____ _____, a wing with an _____ pressure distribution is the most efficient.
Aspect ratio
| Elliptical
393
An elliptical wing produces a _____ and _____ level of downwash across the wing.
Constant
| Reduced
394
An elliptical wing produces a constant section ____ ____ across the _____ _____, the ratio is the same (1.0) across the _____ _____ _____
Lift Coefficient
Entire span
Entire wing span
395
A rectangular wing has large _____ _____ and _____ downwash towards the wing tips, giving sections towards the wing tip a _____ effective angle of attack.
Wingtip vortices
Greater
Smaller
396
Static stability
The immediate response
397
Dynamic Stability
Subsequent response over time
398
Positive static stability
The initial tendency of an object
399
Neutral static stability
Object not wanting to move
400
Negative static stability
Moving further from its original position
401
Positive dynamic stability
Object returns to it's original position
402
Neutral dynamic stability
Object will not settle
403
Negative dynamic stability
The object will move further away from it's original position
404
Positive static stability can lead to...
Positive, Neutral and Negative dynamic stability. With neutral and negative in a periodic motion, and positive in both an aperiodic and periodic motion.
405
Neutral static stability can lead to...
Only Neutral dynamic stability in an aperiodic motion
406
Negative static stability can lead to...
Only Negative dynamic stability in an aperiodic motion.
407
Rolling/yawing to the right is _____ motion
Positive
408
Pitch occurs on the _____ axis and has _____ stability
Lateral
Longitudinal
M
409
Yaw occurs on the _____ axis and has _____ stability
Normal
Directional
N
410
Roll occurs on the _____ axis and has _____ stability
Longitudinal
Lateral
L'
411
On a symmetrical aerofoil the Aerodynamic center (AC) occurs at _____ chord
~25%
412
On a Chambered aerofoil the AC occurs at _____ chord
23 - 27%
413
An aircraft is more stable with stick _____ rather than stick _____
Fixed
| Free
414
The absolute AoA is...
The angle between the RAF and the Zero lift line, it nullifys the effect of the camber
415
The zero lift line is always _____ the chord line on a positively cambered wing
Above
416
Up-gusts _____ the AoA
Increase
417
Down-gusts _____ the AoA
Decrease
418
The AC is _____ the CG
Behind
419
Pitching moment coefficient equation:
Cm = M / q S c
420
The greater the dynamic pressure
The faster you go
421
To increase longitudinal stability:
Increase the horizontal stabiliser size
Move CG forwards
Increase tailplane volume.
422
The forward CG limit makes sure:
Aircraft is not too stable
| There is a minimum level of controllablity
423
The aft CG limit makes sure
Aircraft is not too controllable
| There is minimum level of stability
424
The neutral point is
the point that the plane reacts around for stability. It is always behind the CG
425
The further from the CG the Neutral point is...
the greater the stability
426
Arm to NP
the distance between the current CG and the NP
427
Static margin
the distance between the aft CG limit and NP
428
CG range
the distance between the forward CG limit and the aft CG limit
429
The neurtal point is _____ _____ when the flaps are extended, due to the reduction of _____ _____ at the tail.
furthest forward
| dynamic pressure
430
With stick position stability, as you go faster, there is _____ deflection of the elevator so the stick moves _____
Less
| forward
431
With stick position stability, as you go slower, there is _____ deflection of the elevator so the stick moves _____
more
| backwards
432
With a trim-tab system, stick position stability....
stays the same
433
With a trimmable horizontal stabiliser, stick position stability...
Changes
434
The aerodynamic center must be _____ the CG to have a positive position stability
Behind
435
Stick force stability
the further from the center position you move the stick, the greater the force should be
436
The more trim you have, the _____ the force will be on the stick
Greater
437
The further forward the CG, the _____ the stick force. The further aft the CG, the _____ the stick force
Greater
| lighter
438
The stick force per G will be greater on a _____ aircraft than an _____ aircraft
Transport
| Aerobatic
439
Aerodynamic dampening
After the initial down-force of the tail, the down-force will get smaller due to the airflow angle
440
At a lower alt./slower TAS there is a _____ airflow to the tailplane compared to a higher alt./faster TAS where there is a _____ airflow to the tailplane. Therefore aerodynamic dampening is less at _____ _____
Steeper
Shallower
High alt/faster TAS
441
TAS is __ the IAS at _____, so the stability is ___.
x2
40,000ft
1/2
442
Short oscillations are due to _____ positive dynamic force and Long oscillations are due to _____ positive dynamic force
Strong
| Weak
443
Short oscillation features:
1 -2 secs
not much alt. difference
not much speed difference
444
Long oscillation features:
```
(phugoid)
1 - 2 mins
Increase in airspeed when going down
Decrease in airsped when going up
Larger change in height
```
445
As Static stability increases, dynamic stability _____.
decreases
446
Nose to the left =
+β
447
Nose to the right
-β
448
Nose to the left of RAF - sideslip to the _____
Right
449
Nose to the Right of RAF - sideslip to the _____
left
450
Yaw moment coefficient equation:
Cn = N / qSb
451
The greater the volume, the _____ the directional stability
greater
452
The greater the swept back angle, the _____ the stability
greater
453
Dorsal fins _____ lateral stability and _____ direction stability.
Increase
| Increase
454
Ventral fins _____ lateral stability and _____ direction stability.
Reduce
| Increase
455
Stakes _____ stability
Increase
456
The fuselage can give off a _____ moment
De-stabilising
457
Lateral stability
The stability in a roll
458
Dihedral wings provide _____ stability
Positive
459
Weak lateral and strong directional stability can lead to a _____ _____
Spiral Dive
460
Strong lateral and weak directional stability can lead to a _____ _____
Dutch roll
461
Stability _____ with altitude
decreases
462
The propeller disk represents the __________
Plane of rotation
463
The angle between the plane of rotation and the chord line
Blade angle
464
The angle between the Plane of rotation and the Relative airflow
Helix angle
465
The angle between the Relative airflow and the chord line
AoA
466
The name for the distance between the start point actual distance traveled.
Effective pitch
467
The name for the distance between the start point and the Theoretical distance traveled
Geometric pitch
468
Distance between the Actual distance traveled and the theoretical distance traveled.
Slip
469
The _____ _____ determines the geometric pitch
Blade angle
470
The _____ _____ determines the effective pitch
Helix angle
471
For a fine pitch you need a _____ blade angle
Small
472
For a coarse pitch you need a _____ blade angle
Large
473
Torque force is...
the opposite of what the engine is trying to do.
474
The helix angle for the time is _____ than the helix angle for the hub.
Greater
475
The faster you go the _____ the helix angle
Greater
476
___ is the optimum blade angle
4°
477
____ is the max. blade angle
16°
478
If you increase the RPM, the helix angle will get ____
Smaller
479
High TAS, Low RPM results in
Reverse thrust
480
Fixed pitch propellers
Blade angle is fixed, simplest form
481
Two pitch propellers
Pilot can set either a fine or a coarse pitch
482
Adjustable pitch propellers
Blade angle can be adjusted mechanically on the ground, but then acts as a fixed pitch propeller at that fixed setting
483
Constant speed propellers
One that automaticaly adjusts it's blade angle at different flight speeds to maintain the ideal AoA
484
The smaller the AoA on a prop blade, the _____ the drag
Greater
485
During take off, the prop is at _____ pitch
Fine
486
As the TAS increases the blade should become more _____
Coarse
487
The blade angle of a fixed pitch prop increases when RPM _____ or TAS _____
Increases
| Decreases
488
Windmilling
When the engine has failed but the blade is still spinning and producing drag
489
Feathering
Increasing the pitch of the blade to reduce drag
490
To increase the pitch of the blade, you need to _____ the RPM by moving the pitch leaver _____. This takes the blade to a _____ position
Reduce
Backwards
Coarse
491
For a variable pitch prop, the faster you go, the _____ the pitch
greater
492
To increase torque absorption you need to _____ blade solidarity. We can do this by:
Increase
Increasing no. of blades
increasing the chord.
493
Beyond 6 blades, we lose efficiency because
They interfere with the flow of the flowing blade.
494
Propellers with more than one hub are known as
Contra rotating propellers
495
Torque reaction effect is:
Where the engine wants to spin the aircraft in the opposite direction of the prop
496
The heavier you are, the _____ the roll rate due torque reaction
Slower
497
The greater the blade size, the _____ the torque reaction
Greater
498
The more power you have, the _____ the torque reaction
Greater
499
Consequences of torque reaction on take-off:
Thrust is at its greatest so torque is at its greatest
| Heavier on the left wheel and lighter on the right, causing yaw to the left on the runway.
500
Slipstream effect:
Airflow flips around around the body due to prop wash and hits the fin at an angle, pushing it to the right and causing yaw to the left.
It also rolls the tail to the right.
501
The slipstream effect is greatest at _____ power setting and _____ speed.
High
| Slow
502
Asymmetric Blade Effect - P Factor:
As aircraft's AoA increases, the prop disk has a greater angle which results in the down-going blade producing greater lift. This produces a yaw to the right.
503
Gyro effect:
Produces a force 90° to the point where the force is produced.
504
Prop icing forms towards the _____. It can reduces the efficiency by up to ___
Hub
| 20%
505
With a left engine failure, the aircraft will yaw to the _____.
left
506
Factors that affect the size of the yawing moment:
The amount of thrust being generated by the left engine
The distance the live engine is from the aircraft's CG
The size of any additional drag moments caused
507
On a prop aircraft with 2 engines, more _____ will be provided on the wing with working engine and there would be more _____ on the dead wing. This causes the aircraft to _____ and _____ towards the _____ wing. If this is not stopped, the aircraft will enter a _____ _____
```
Lift
Drag
Roll
yaw
Dead
Spiral dive
```
508
The two methods to gain equilibrium from asymmetric flight
The wings level method
| The banking method
509
The wings level method:
Apply rudder to balance the moments
510
Disadvantages of the wings level method:
Increases drag from the fin, reducing limited excess thrust + performance.
Fin must be set at a large AoA to produce sufficient force . - chance of fin stall
511
The banking method:
Applying no more than 5° bank towards the live engine.
512
Disadvantages of the banking method:
In-balance of the slip indicator
| More chance of disorientation
513
advantages of the banking method:
Less drag
| less risk of fin stall
514
For directional control, you have better control at ____ altitude and _____ temperature
High
| High
515
The critical engine:
The engine that, if it fails, results in the largest yaw moment produced by the remaining engine.
516
The factors determining which the critical engine is:
Length of the moment arm from the thrust lines
slipstream effects
Torque reaction effects
Weathercock tendency
517
On a prop aircraft with a right down blade, the ____ engine is the critical engine
left
518
With a jet the direction the wind is _____ _____ is the critical engine.
coming from
519
On a 4 engine jet aircraft, the __________ engine is the critical engine
outboard into-wind
520
Minimum control speed:
the minimum speed required for directional control
521
Vmc
airborne minimum control speed
522
Vmcl
landing configuration minimum control speed
523
Vmcg
Ground minimum control speed
524
Vmc is determined by:
min. thrust
Aft CG (most unfavorable)
trimmed for take-off
Max. take-off weight
most critical take off configuration (with gear up)
aircraft is airborne and out of ground effect
If prop - dead engine is windmilling, (if auto-feather is available, feathered)
rudder pedal force must not exceed 150lb
525
Vmcl is determined by:
```
Maximum thrust
Aft CG (most unfavorable)
Aircraft trimmed for approach
min. weight (most unfavorable)
most critical landing configuration
minimum roll of 20° in 5 secs towards live engine
rudder pedal force must not exceed 150lb
```
526
Vmcg
```
Maximum thrust
Aft CG (most unfavorable)
Aircraft trimmed for take-off
min. mass (most unfavorable)
most critical take-off configuration
maintain control with rudder only, max. 30ft deviation from the center line
```
527
Mach no. equation
M = TAS/LSS
528
LSS equation
LSS = 39 x √absolute temp(k)
529
As you get higher, the LSS will get _____
smaller
530
subsonic
Mach no. <1
531
sonic
mach no = 1
532
supersonic
mach no. >1
533
M0.4 is the point where
compressablity takes factor
534
Mcrit
The point where the first LSS reaches supersonic
535
Transonic
Where some LSS are subsonic, some sonic, some supersonic
536
Mdet
The point where all LLS become supersonic
537
Fist shockwave created:
Normal shockwave
538
A normal shockwave is caused by
Partials where mach >1 collide with partials mach <1
539
The mach no. is a _____ behind the shockwave, with a distance of _____
reciprocal
| 0.0025mm
540
The faster you go, the _____ the drag from the shockwave.
greater
541
Oblique shockwave
Supersonic flow in-front and behind shockwave, just slower supersonic flow behind
542
Oblique shockwaves occur at
the leading and trailing edge
543
Bow wave:
Oblique shockwaves above and below the wing, a normal shockwave by the leading edge due to the stagnation zone
544
Ailerons outside of the mach cone are _____
ineffective
545
In expansion waves there is:
```
greater static pressure
colder air
less density
faster moving air
No change in energy
```
546
Expansion waves effects:
```
Increases - Mach
Decreases -
Ps
density
temperature
Pt stays the same
```
547
Norma/oblique waves effects
```
Decreases -
Mach
Pt
Increases -
Ps
density
temperature
```
548
Mdetached occurs at
1.3 mach
549
Operating MMO
The max. mach no. - climbing
550
Operating VMO
the max. calibrated speed - descending
551
The is more pressure differential _____ of the shockwave
in-front
552
When going through Mcrit, initially:
Cl slightly increases and Cd slightly decreases
553
After -
Cl significantly decreases and Cd significantly increases
554
Shock stall -
The point when the lift coefficient, as a function of Mach no., goes beyond it's maximum value.
555
At MFS = 1.0 -
Cd drops
| Oblique shockwaves form at the trailing edge
556
Mach tuck -
Cp moves back
Points nose down. increases speed - exceeding max. operating speed
Tailplane becomes less effective due to increase in turbulent air coming off the wing.
557
Mach trim
When approaching transonic, trims horizontal stabiliser to avoid mach tuck
558
Super-critical wings do
Mcrit differed
delays Mdrag divergence
Allows us to travel faster
559
Mach buzz
felt through controls when approaching Mach 1.0 due to formation of a shockwave
560
High-speed buffet
High speed tumbling wake may hit the airframe/horizontal stabiliser causing buffet.
561
For a greater margin between high-speed buffet and low speed buffet you should...
descend to a lower altitude.
562
Aerodynamic ceiling
Altitude at which you'll either enter a high speed stall or a lowspeed stall.
563
Transport aircraft load limits
Positive: 2.5g
Negative: -1g
Ultimate: 3.75g
564
Utility aircraft load limits
Positive: 4.4g
Negative: -1.76g
Ultimate: 6.6g
565
Aerobatic load limits
Positive: 6g
Ultimate: 9g
566
the ultimate load is ___ more than the load limit
50%
567
in level flight, the load factor is ___
1
568
VA
The highest speed at which sudden, full-up elevator deflection can be made without exceeding the limit load factor.
569
VA equation
VA = VA(current) x √New weight/old weight
570
With flaps extended, the maximum load limit is reduced to ___ on a transport aircraft
2g
571
VB
The design speed for maximum gust - up to 66fps at 20,000ft
| Faster than VA, Slower than VC
572
Vc/Mc
Maximum permissible cruise EAS/Mach no.
Always exceed VMO/MMO
Must withstand gusts of 50fps
573
VD
the speed increase from Vc/Mc where the areoplane is flow for 20 secs along a flight path 7.5° below the initail path and then up at a load factor of 1.5g.
Withstand gusts of 25fps
574
VNE
Never exceed speed (light aircraft)
575
VNO
Max. structural cruise speed
576
VLE
Max. landing gear extended speed
577
VLO
Max. landing gear operating speed
578
VFE
Max. flap extension speed
579
VRA
Rough air speed (35kts less than VMO)
Recommended penetration airspeed
- Fast enough to avoid stalling
-Slow enough to avoid structural damage
580
Conditions affecting the load factor
Rectangular wing effected more
Light aircraft effected more
Faster airspeed effected more
Low altitude effected more
581
New LF equation
Increase in LF x (New speed/ old speed)
582
High speed aileron Reversal
Aileron reversal due to large aerodynamic forces twisting the wing when aileron is moved.
583
A contaminated wing effects
```
Reduce stalling AOA
Reduce Cl
Increase Stall Speed
Increase Drag
Climb performance decreases
```
584
Ice tends to accumulate at speeds below _____ IAS and lower altitudes in visible mosisture and between ___ and ___
250kts
| 0 - 20°C
585
_____ aircraft are more susceptible to ice
Prop
