PoF Flashcards
Provided that there is no flow separation and no compressibility effects, the location of the aerodynamic centre (AC) _____ .
1- is at approximately 50% chord, regardless of the angle of attack
2- is at approximately 25% chord, regardless of the angle of attack
3- depends on the angle of attack
4- moves forward with an increasing angle of attack
is at approximately 25% chord, regardless of the angle of attack
= Point at which pitching moment does not vary with AoA
The wing is called anhedral if ______.
1- the wing tip and the root are on the same level
2- its wing tip is higher than the wing root
3- its wing root is higher than the tip
4- the line of the 25% chord is at the angle to the root chord
its wing root is higher than the tip
Dihedral angle = Angle between forizontal plane and wing suface at the tip
-Dihedral wing (angle > 0º) = Tip higher than root / root lower than tip
-Anhedral wing (Angle < 0º) = Tip lower than root / root higher than tip
Which is the correct definition of the dihedral angle?
1- The dihedral angle is the angle between the horizontal and the wing surface
2- The dihedral angle is the angle between the line of the 25% chord and the perpendicular to the root chord
3- The dihedral angle is the angle between the chord line and the horizon
4- The dihedral angle is the angle between the leading and trailing edge of the wing
The dihedral angle is the angle between the horizontal and the wing surface
Dihedral angle = Angle between forizontal plane and wing suface at the tip
-Dihedral wing (angle > 0º) = Tip higher than root / root lower than tip
-Anhedral wing (Angle < 0º) = Tip lower than root / root higher than tip
What are the parameters affecting the density? Select the most complete answer.
1- All answers are correct
2- Static pressure
3- Temperature
4- Humidity
All answers are correct
Higher pressure = Higher density
Higher temperature = Lower density
Higher humidity = Lower density
The angle of incidence is ____.
1- the angle between the line of 25% chord and the perpendicular to the root chord
2- the angle between the relative airflow and the wing chord line
3- the angle between the chord line and the horizon
4- the angle between the aircraft’s longitudinal axis and the wing chord line
the angle between the aircraft’s longitudinal axis and the wing chord line
Angle of incidence = the angle between the aircraft’s longitudinal axis and the wing chord line
Sweep angle = the angle between the line of 25% chord and the perpendicular to the root chord
Angle of Attack = the angle between the relative airflow and the wing chord line
Pitch angle = the angle between the chord line and the horizon
What is the SI unit of pressure?
1- Newton [N]
2- Pascal [Pa]
3- psi
4- bar
Pascal [Pa]
Newton (N) = FORCE
* Which statement describes the aerodynamic centre (AC)?*
1- It is the point where the velocity is reduced to zero
2- It is the point where the resultant aerodynamic force acts
3- It is the point where the pitching moment coefficient does not vary with the angle of attack
4- It is the point where the aeroplane’s lateral axis intersects with the centre of gravity
It is the point where the pitching moment coefficient does not vary with the angle of attack
Stagnation point = It is the point where the velocity is reduced to zero
Center of pressure point = It is the point where the resultant aerodynamic force acts
Mean aerodynamic chord (MAC) = It is the point where the aeroplane’s lateral axis intersects with the centre of gravity
Which are the components of the profile drag?
1- Pressure and induced drag
2- Skin friction, pressure and wave drag
3- Skin friction and wave drag
4- Skin friction and pressure drag
Skin friction and pressure drag
-Total (profile) drag = Pressure drag + Skin drag
-SKIN DRAG –> developed at the boundary layer ( where air velocity goes from zero at the surface to the value of undisturbed airflow):
-Airflow at the boundary layer of the leading edge is LAMINAR w/ less change in velocity = Less skin drag
-Airflow at the boundary layer of the trailing edge is TURBULENT w/ more change in velocty = Higher skin drag
-PRESSURE DRAG –> Results from differnce between leading (higher) and trailing (lower) edges.
How can the stagnation point be described?
1- It is the point of intersection of the total aerodynamic force and the chord line
2- It is the point where the velocity is reduced to zero
3- It is the point, relative to which the sum of all moments is independent of the angle of attack
4- It is the point of intersection of the thrust vector and the chord line
It is the point where the velocity is reduced to zero
Stagnation point:
= Point where velocity of relative airflow is reduzed to zero
-Static pressure reaches maximum value
-Icing is most likely to form aroudn this point
-Depends on AoA –> At highet AoA it moves to the lower surface!
In a symmetrical aerofoil, the mean camber line is ____.
1- collinear with the cord line
2- collinear with the upper surface
3- collinear with the lower surface
4- perpendicular to the relative airflow
collinear with the cord line
Symmetrical wing –> Cambe rline = Chord line; Center of pressure does not change w/ AoA and coincidental w/ aerodynamic center
Positive camber = Camber line higher than chord line
Negative camber = Camber line lower than chord line
What are the factors influencing the induced drag? I - Angle of incidence, II - Airspeed, III - Wingspan, IV - Aspect ratio, V - Lift magnitude
1- II, IV, V
2- I, III
3- I, II, III, IV, V
4- II, III, V
II, IV, V
Airspeed; Aspect ratio; Lift magnitude
How to reduce induced drag / wake turbulence / tip vortices?
- Higher aspect ratio
- Less wingspan
- Higher speed
- Lower mass
- Lower AoA
- Less lift
- Winglets
- Wing shape –> Eliptical wing
- Fit wing with tip tank (weight on the tip)
- Configuration –> use of lift augmentation devices (clean config is worse!!!)
With regard to changing weight, which of the following statements is correct?
1- The parasite drag does not depend on the weight, the induced drag increases with weight
2- The parasite drag increases the weight, the induced drag decreases with weight
3- The parasite drag and the induced drag increase with weight
4- No other answer is correct
The parasite drag does not depend on the weight, the induced drag increases with weight
TOTAL (Profile) DRAG =
INDUCED DRAG + PARASITE DRAG
Weight:
–> Affects induced drag (more weight = more drag) but not parasite drag
Speed:
–> Higher speed = Lower induced drag
–> Higher speed = Higher parasite drag
Parasite drag (“PIS”):
-Pressure (form) drag –> Originates from pressure differential between leading (higher) and trailing (lower) edges; Depends on cross section area (higher area = higher drag) and shape (3:1 = best)
-Interference drag –> Originates from boundary layer interference at junction of different parts ; Reduced by fillets
-Skin (friction) drag –> Originates from fluid viscosity (leading edge = laminar flow = less drag; trailing edge = turbulent flow = more drag); Depends on surface roughness (more rough = more drag)
Trailing edge vortices___ .
1- are stronger at lower angles of attack
2- are present only at high angles of attack
3- are not influenced by the angle of attack
4- are stronger at higher angles of attack
are stronger at lower angles of attack
How to reduce induced drag / wake turbulence / tip vortices?
- Higher aspect ratio
- Less wingspan
- Higher speed
- Lower mass
- Lower AoA
- Less lift
- Winglets
- Wing shape –> Eliptical wing
- Fit wing with tip tank (weight on the tip)
- Configuration –> use of lift augmentation devices (clean config is worse!!!)
The wake turbulence vortices tend to____ .
1- stay on the same level
2- ascend to a higher level
3- descend to a lower level
4- stay on the ground level
descend to a lower level
Lenght up to 9 NM
Drift downwards about 500 - 1000ft below aircraft flight path
How can the induced drag be reduced? Select the most complete answer.
1- By winglets
2- By greater wingspan
3- By decreasing the mass on the wing tips
4- All answers are correct
By winglets
How to reduce induced drag / wake turbulence / tip vortices?
- Higher aspect ratio
- Less wingspan
- Higher speed
- Lower mass
- Lower AoA
- Less lift
- Winglets
- Wing shape –> Eliptical wing
- Fit wing with tip tank (weight on the tip)
- Configuration –> use of lift augmentation devices (clean config is worse!!!)
Regarding the spanwise flow on the wing_____ .
1- the air flows from the root to the tip on the lower and the upper side of the wing
2- on the lower side of the wing the air flows from the wing root to the tip, and on the upper side from the tip to the root
3- the air flows from the tip to the root on the lower and the upper side of the wing
4- on the lower side of the wing the air flows from the wing tip to the root, and on the upper side from the root to the tip
on the lower side of the wing the air flows from the wing root to the tip, and on the upper side from the tip to the root
The length of the wake turbulence can reach up to ____.
1- 9 NM
2- 12 NM
3- 20 NM
4- 1 NM
9 NM
Lenght up to 9 NM
Drift downwards about 500 - 1000ft below aircraft flight path
What are the factors influencing wake turbulence? I - Weight, II - Airspeed, III - Wingspan, IV - Taper ratio, V - angle of attack, VI - pitch attitude, VII - aircraft’s configuration
1- I, II, IV, V
2- I, II, III, V, VII
3- I, III, V, VI
4- II, IV, VI, VII
I, II, III, V, VII
Weight; Airspeed; Wingspan; AoA; configuration
How to reduce induced drag / wake turbulence / tip vortices?
- Higher aspect ratio
- Less wingspan
- Higher speed
- Lower mass
- Lower AoA
- Less lift
- Winglets
- Wing shape –> Eliptical wing
- Fit wing with tip tank (weight on the tip)
- Configuration –> use of lift augmentation devices (clean config is worse!!!)
Which type of drag will increase if the wing surface becomes contaminated? Select the most complete answer.
1- Induced drag
2- All answers are correct
3- Interference drag
4- Skin friction drag
Skin friction drag
TOTAL (Profile) DRAG =
INDUCED DRAG + PARASITE DRAG
Weight:
–> Affects induced drag (more weight = more drag) but not parasite drag
Speed:
–> Higher speed = Lower induced drag
–> Higher speed = Higher parasite drag
Parasite drag (“PIS”):
-Pressure (form) drag –> Originates from pressure differential between leading (higher) and trailing (lower) edges; Depends on cross section area (higher area = higher drag) and shape (3:1 = best)
-Interference drag –> Originates from boundary layer interference at junction of different parts ; Reduced by fillets
-Skin (friction) drag –> Originates from fluid viscosity (leading edge = laminar flow = less drag; trailing edge = turbulent flow = more drag); Depends on surface roughness (more rough = more drag)
Which of the following statements is correct?
1- The induced drag increases and the parasite drag decreases with airspeed
2- The induced drag and the parasite drag increase with airspeed
3- The induced drag decreases and the parasite drag increases with airspeed
4- The induced drag and the parasite drag decrease with airspeed
The induced drag decreases and the parasite drag increases with airspeed
TOTAL (Profile) DRAG =
INDUCED DRAG + PARASITE DRAG
Weight:
–> Affects induced drag (more weight = more drag) but not parasite drag
Speed:
–> Higher speed = Lower induced drag
–> Higher speed = Higher parasite drag
Parasite drag (“PIS”):
-Pressure (form) drag –> Originates from pressure differential between leading (higher) and trailing (lower) edges; Depends on cross section area (higher area = higher drag) and shape (3:1 = best)
-Interference drag –> Originates from boundary layer interference at junction of different parts ; Reduced by fillets
-Skin (friction) drag –> Originates from fluid viscosity (leading edge = laminar flow = less drag; trailing edge = turbulent flow = more drag); Depends on surface roughness (more rough = more drag)
Where can the vortex generator be found?
1- On the upper side of the wing near the leading edge
2- On the upper side of the wing near the trailing edge
3- On the lower side of the wing near the trailing edge
4- On both sides of the wing near the trailing edge
On the upper side of the wing near the leading edge
VORTEX GENERATORS:
-Located on the upper surface of wing near the leading edge
-Transfer energy from free airflow to boundary layer (energizes boundary layer), reducing separation and decreasing stall speed
-Advantages:
-Better control surface effectiveness
-Smoother ride in turbulence
-Less noise
-Decrease stall speed
-Disadvantages:
-Decrease cruise speed
-Harder ice and snow clearence
Which type of trailing edge flaps offers the highest CLMAX increase?
1- Fowler flap
2- Slotted flap
3- Plain flap
4- Split flap
Fowler flap
Fowler (highest CLmax and lowest drag)
> Slotted
> Split
> Plain (used in light aircraft)
Which of the following are high lift devices? I - Trailing edge flaps, II - Leading edge slats, III - Spoilers, IV - Krueger flaps, V - Ailerons
1- I, II, IV
2- I, II, III, IV
3- II, IV, V
4- I, III, III, V
I, II, IV
CL max may be increased by:
-Boundary layer control
-Leading edge slats or Krueger flaps
-Trailing edges flaps
What is the effect of slats extension on the take-off and landing distances?
1- The take-off and landing distances decrease with slats extended
2- The take-off and landing distances increase with slats extended
3- Slats extension does not influence the take-off and landing distances
4- The take-off distance increases and landing distance decreases with flaps extended
The take-off and landing distances decrease with slats extended
Slats and Flaps have the same effects!
During landing:
-Lower landing speed
-Steeper descent angle w/o airspeed increase
-Decrease landing distance
During T/O:
-T/O distance decrease
-Decreased climb angle
-Increased glide angle
The aged airframe will produce _____ as compared to a new airframe.
1- increased interference drag
2- increased induced drag
3- increased skin friction drag
4- increased form drag
increased skin friction drag
What is the effect of flaps extension on the take-off and landing distances?
1- Flaps extension does not influence the take-off and landing distances
2- The take-off and landing distances increase with flaps extended
3- The take-off and landing distances decrease with flaps extended
4- The take-off distance increases and landing distance decreases with flaps extended
The take-off and landing distances decrease with flaps extended
Slats and Flaps have the same effects!
During landing:
-Lower landing speed
-Steeper descent angle w/o airspeed increase
-Decrease landing distance
During T/O:
-T/O distance decrease
-Decreased climb angle
-Increased glide angle
Which of the following statements regarding the effect of flap extension is correct?
1- The aeroplane with flaps extended will have a decreased climb angle and glide angle
2- The aeroplane with flaps extended will have an increased climb angle and decreased glide angle
3- The aeroplane with flaps extended will have increased climb angle glide angle
4- The aeroplane with flaps extended will have a decreased climb angle and increased glide angle
The aeroplane with flaps extended will have a decreased climb angle and increased glide angle
Slats and Flaps have the same effects!
During landing:
-Lower landing speed
-Steeper descent angle w/o airspeed increase
-Decrease landing distance
During T/O:
-T/O distance decrease
-Decreased climb angle
-Increased glide angle
With regard to the ground effect, below which height the reduction in the induced drag becomes significant?
1- Below height equal to the wing span
2- Below height equal to a quarter of the wing span
3- Below 1000 ft
4- Below height equal to the half of the wing span
Below height equal to the half of the wing span
With regard to the ground effect, which statement is correct?
1- Lift and the induced drag decrease
2- Lift increases and induced drag decreases
3- Lift and the induced drag increase
4- Lift decreases and the induced drag increases
Lift increases and induced drag decreases
GROUND EFFECT:
-When the height is less than half the wingspan
-Heat decreased ground effect (less density)
-ENTERING GROUND EFFECT:
(“LEID Di has double DD’s but Wants to Change”)
-L = Lift coefficient increase (higher CL/CD) -E = Effective AoA increase (with decrease in critical AoA which may lead to stall) -I = Induced AoA decrease -D = Downwash angle decrease -Di = Drag Induced decrease (less wingtip vortices) DD = Decreased decceleration (if throttle is not reduced, aircraft may climb above desired glide path) W = Wing stall (leads to heavy landing) C = Change in position error (ASI and altimeter underread)
* Which of the following are the effects of the ice formation on the wing? Select the most complete answer.*
1- Earlier separation
2- Increased skin friction drag
3- CLMAX and the critical angle of attack decrease
4- All answers are correct
All answers are correct
Ice build-up locations:
-Leading edges and vertical and horizontal stabilizers
-Engine inlets
-Propellers
-Measurement equipment
-Windows
Ice build-up effects:
-Increase surface roughness –> Increase skin drag (total drag increases by 40%)
-CLMAX and the critical angle of attack decrease (lift decreased by 30%)
-Earlier flow separation (w/ higher stall speed)
Which of the following statements about the laminar boundary layer is NOT true?
1- In a laminar boundary layer, the fluid flow is smooth, without any turbulence or vortices
2- The laminar flow carries more energy than the turbulent one and is thus less susceptible to separation
3- In a laminar boundary layer, the fluid speed decreases slowly as it gets closer to the wall
4- A laminar boundary layer produces little drag
The laminar flow carries more energy than the turbulent one and is thus less susceptible to separation
BOUNDARY LAYER:
= Layer where airflow velocity changes from zero at the aerofoil’s surface to the value o undisturbed airflow
-Boundary layer thickness = From surface to 99% velocity of undisturbed airflow (increases w/ distance from leading edge)
-Transition point = Laminar boundary layer turns into turbulent boundary layer
-LAMINAR boundary layer –> Thinner; less energy; less friction drag; more susceptible to flow separation
-TURBULENT boundary layer –> Thicker; more energy; more friction drag; less susceptible to flow separation
What is the boundary layer transition?
1- It is the transition between the turbulent boundary layer and the undisturbed airflow
2- It is the transition between the laminar boundary layer and the undisturbed airflow
3- It is the transition from the laminar boundary layer to the turbulent boundary layer
4- It is the transition from the turbulent boundary layer to the laminar boundary layer
It is the transition from the laminar boundary layer to the turbulent boundary layer
BOUNDARY LAYER:
= Layer where airflow velocity changes from zero at the aerofoil’s surface to the value o undisturbed airflow
-Boundary layer thickness = From surface to 99% velocity of undisturbed airflow (increases w/ distance from leading edge)
-Transition point = Laminar boundary layer turns into turbulent boundary layer
-LAMINAR boundary layer –> Thinner; less energy; less friction drag; more susceptible to flow separation
-TURBULENT boundary layer –> Thicker; more energy; more friction drag; less susceptible to flow separation
What change in the attitude of the aeroplane is caused by one wing stalling before the other?
1- The uncommanded rolling motion towards the stalled wing
2- Uncommanded rolling motion away from the stalled wing
3- Uncommanded pitch-down
4- Uncommanded pitch-up
The uncommanded rolling motion towards the stalled wing
Stall characteristics:
- Reduced effectiveness of flight controlls
- Uncommanded pitch down (due to loss of lift)
- Uncommanded roll (due to one wing stalling before the other one –> towards the stalled wing)
Why does special attention need to be paid when using ailerons in a nearly-stalled aeroplane?
1- Deflecting the aileron down increases the aerofoil camber, which can cause a portion of the wing to stall, reversing the effect of aileron deflection
2- Due to the attitude of the aeroplane, the access to the cockpit controls is more difficult for the pilot
3- Deflecting the aileron down increases the aerofoil camber, which very strongly increases the effectiveness of the ailerons at high angles of attack
4- With an increase in Angle of Attack, the Centre of Pressure moves towards the trailing edge, which means that the Centre of Pressure can move to the hinge of the aileron, locking it in place
Deflecting the aileron down increases the aerofoil camber, which can cause a portion of the wing to stall, reversing the effect of aileron deflection
What is the effect of increasing the Angle of Attack (AoA) on the location of the separation point?
1- As the AoA increases, the separation point moves forward
2- As the AoA increases, the separation point moves backwards
3- The location of the separation point does not depend on the AoA
4- With an increase in AoA, the separation point disappears
As the AoA increases, the separation point moves forward
SEPARATION POINT:
= Airflow stops following the curvature of the wing and starts moving freely
-At low AoA –> Separation point is located near the trailing edge
-As AoA increases –> Separation point moves forward
How does wing contamination affect the stalling speed?
1- Due to the reduced C_L, the stalling speed increases
2- Due to the reduced C_L, the stalling speed decreases
3- Due to the increased C_L, the stalling speed decreases
4- Due to the increased C_L, the stalling speed increases
Due to the reduced C_L, the stalling speed increases
WING CONTAMINATION:
-More surface roughness –> more skin drag (increased drag by 40%)
-Earlier flow separation
-Reduced CL max (decreased lift by 30%)
-Reduced critical AoA
-Increased stall speed
What is the separation point?
1- It is the transition from the laminar boundary layer to the turbulent boundary layer
2- It is the point where the airflow stops following the curvature of the wing and starts moving freely
3- It is the point on the aerofoil where the speed of airflow is 0
4- It is the point at which the fluid flow reverses direction
It is the point where the airflow stops following the curvature of the wing and starts moving freely
SEPARATION POINT:
= Airflow stops following the curvature of the wing and starts moving freely
-At low AoA –> Separation point is located near the trailing edge
-As AoA increases –> Separation point moves forward
Which of the following statements about the turbulent boundary layer is NOT true?
1- The turbulent flow carries more energy than the laminar flow, which makes it less susceptible to separation
2- The turbulent flow carries less energy than the laminar flow, which makes it more susceptible to separation
3- In a turbulent boundary layer, the fluid speed decreases rapidly near the wall
4- The turbulent boundary layer produces less drag
The turbulent boundary layer produces less drag
BOUNDARY LAYER:
= Layer where airflow velocity changes from zero at the aerofoil’s surface to the value o undisturbed airflow
-Boundary layer thickness = From surface to 99% velocity of undisturbed airflow (increases w/ distance from leading edge)
-Transition point = Laminar boundary layer turns into turbulent boundary layer
-LAMINAR boundary layer –> Thinner; less energy; less friction drag; more susceptible to flow separation
-TURBULENT boundary layer –> Thicker; more energy; more friction drag; less susceptible to flow separation
How and why does the stalling speed change in flight with a load factor n>1 compared to a straight and level flight?
1- Flying with a bank angle introduces a perpendicular component to the airflow over the wings, decreasing the generated lift and necessitating an increase in speed
2- With a higher load factor more lift is needed, so for a given maximum CL the speed must be increased to keep the aeroplane aloft
3- The centrifugal force helps the lift in overcoming the weight of the aircraft, and the stalling speed decreases
4- The stalling speed remains constant, as it only depends on the Angle of Attack of the wing
With a higher load factor more lift is needed, so for a given maximum CL the speed must be increased to keep the aeroplane aloft
STALL SPEED:
Vsr = Reference stall speed
Vs0 = Stall speed in landing configuration
Vs1 = Stall speed in specific configuration
Vs1g = Minimum speed at which lift = weight
Vs = √ load factor * ( (aircraft weight*2) / (density * surface of wings * CL max))
Load factor (n) = Lift / Weight = 1 / cos (bank angle)
n = 1 –> Steady straight level flight
n < 1 –> steady climb or descent
n > 1 –> HIGHER STALL SPEED –> gust, pulling out of a dive, turn
Factors that increase stall speed:
-More weight
-Swept wing / less wing surface area / higher wing loading
-Forward center of gravity
-High altitude (less desity)
-More bank angle
-Turbulence
-Icing
-Pulling out of a dive
-Less thrust
At what Angle of Attack (AoA) is the maximum CL achieved?
1- At the critical AoA
2- At the minimum drag coefficient AoA
3- At the best Lift/Drag (L/D) AoA
4- At the best glide endurance AoA
At the critical AoA
Optimum AoA (4º) = Max L/D
Critical AoA (16º) = Max Lift (CL)
How does icing affect the CL and stall speed?
1- Icing decreases C_L, which decreases the stall speed
2- Icing decreases C_L, which increases the stall speed
3- Icing increases C_L, which decreases the stall speed
4- Icing increases C_L, which increases the stall speed
Icing decreases C_L, which increases the stall speed
Ice build-up locations:
-Leading edges and vertical and horizontal stabilizers
-Engine inlets
-Propellers
-Measurement equipment
-Windows
Ice build-up effects:
-Increase surface roughness –> Increase skin drag (total drag increases by 40%)
-CLMAX and the critical angle of attack decrease (lift decreased by 30%)
-Earlier flow separation (w/ higher stall speed)
How does the flapper switch work?
1- As the Angle of Attack (AoA) increases, it deflects a flap on the fuselage which feeds a signal to the computer in the cockpit
2- It informs the pilot about the imminent stall by vibrating (or flapping) the control column
3- As the AoA increases, the stagnation point moves, and once it reaches the location of the flapper switch, the switch and the stall warning are activated
4- It informs the pilot about overspeeding the aircraft by vibrating (or flapping) the control column
As the AoA increases, the stagnation point moves, and once it reaches the location of the flapper switch, the switch and the stall warning are activated
STALL WARNING:
-Pre-stall buffet –> Most apparent phenomenon preceeding a stall –> = Quick oscillations caused by turbulent flow impinging on the horizontal stabilizer
-Flapper switch –> As the AoA increases, the stagnation point moves, and once it reaches the location of the flapper switch, the switch and the stall warning are activated
-Stall horn –> Most common in general aviation –> Hole in the wing. When AoA increases, it creates low pressure around the hole –> suction general airflow through the horn, making a sound
Stick shaker –> Activates at lower angle than stick pusher. It’s triggered by airspeed higher than Vs. Input from AoA and rate of AoA change.
How does flying through heavy rain influence the aeroplane’s performance?
1- When flying through heavy rain, the aeroplane’s weight slightly increases, the drag increases and the lift increases
2- When flying through heavy rain, the aeroplane’s weight slightly increases, the drag decreases and the lift increases
3- When flying through heavy rain, the aeroplane’s weight slightly increases, the drag increases and the lift decreases
4- When flying through heavy rain, the aeroplane’s weight slightly decreases, the drag decreases and the lift increases
When flying through heavy rain, the aeroplane’s weight slightly increases, the drag increases and the lift decreases
With rain:
-Aircraft weight increases by 2%
-Drag increases by 30%
-Lift decreases
Why are stabiliser aerofoils more susceptible to icing than the aerofoils found on the wings?
1- Because stabilisers aerofoils are thinner
2- Because stabilisers’ aerofoils are thicker
3- Because stabilisers’ aerofoils are symmetrical
4- Because stabilisers’ aerofoils are set at a lower angle of incidence and experience downwash from the wings
Because stabilisers aerofoils are thinner
What is the Holdover Time (HOT)?
1- It is a time duration for which the aeroplane is supposed to hold over a given waypoint in low-visibility conditions
2- It is the time for which the onboard supplies of anti-ice chemical products will last in icing conditions
3- It is a time for which the engines can be run at the max power, preventing the snow and ice from accumulating on the aeroplane
4- It is a time during which the anti-ice fluid prevents the snow and ice from accumulating on the aeroplane in given atmospheric conditions
It is a time during which the anti-ice fluid prevents the snow and ice from accumulating on the aeroplane in given atmospheric conditions
What is a super stall (also known as a deep stall)?
1- It is a stall that is unrecoverable, due to the excessive pitch-up moment and reduced elevator authority
2- It is a stall which is reached very fast, due to the excessive pitch-up rate of the aeroplane
3- It is a stall that is reached very slow, due to the low pitch-up rate of the aeroplane, which means it possibly can be undetected by the pilot
4- It is a stall that is reached at a low Angle of Attack (AoA) due to the aerodynamic properties of the aeroplane
It is a stall that is unrecoverable, due to the excessive pitch-up moment and reduced elevator authority
Why are stall speed margins used during aeroplane operations?
1- To improve the fuel efficiency during take-off and landing operations
2- To ensure the safety of operation in case of pilot error or an unaccounted difference in parameters affecting the stall speed
3- To protect the airframe from excessive loads generated by heavy maneuvres
4- To ensure compliance with ATC law requirements
To ensure the safety of operation in case of pilot error or an unaccounted difference in parameters affecting the stall speed
What is the purpose of stall warning systems?
1- They allow the pilot to monitor the Angle of Attack (AoA)
2- They inform the pilot about the loss of power in the engine
3- They prevent the aeroplane susceptible to the deep stall from entering it by physically moving the control column
4- They inform the pilot about the imminent stall
They inform the pilot about the imminent stall
How can the deployment of flaps cause the stall of the horizontal stabiliser?
1- Deployment of the flaps increases downwash from the wings, increasing the Angle of Attack (AoA) of the stabiliser, which can lead to a stall
2- Deployment of the flaps increases downwash from the wings, decreasing the Angle of Attack (AoA) of the stabiliser, which can lead to a stall
3- Deployment of the flaps increases the camber of the stabiliser, which can lead to a stall
4- Deployment of the flaps decreases the camber of the stabiliser, which can lead to a stall
Deployment of the flaps increases downwash from the wings, increasing the Angle of Attack (AoA) of the stabiliser, which can lead to a stall
Which of these statements about the spin is NOT true?
1- In a spin, the Angle of Attack (AoA) is the same on both wings
2- In a spin, the aeroplane descends in a rotational movement
3- The spin must be preceded by the stall
4- In a spin, both wings are stalled
In a spin, the Angle of Attack (AoA) is the same on both wings
SPIN:
-Always preceeded by stall
-Both wings are stalled, but one more than the other (different AoA)
-In a spin, the aeroplane descends in a rotational movement
-Turn indicator shows direction of rotation
-Slip/skid ball is unreliable
Factors causing spin:
-Uncoordinated maneuvers
-Center of gravity lateral displacement
-Abrupt control inputs at high AoA
Spin phases:
1- Incipient
2- Developed
3- Recovery –> decrease power to idle –> Neutral ailerons –> Full opposite rudder –> Pitch down (yoke forward)
Which of the following statement about static stability is correct? Select the most complete answer.
1- Static stability is classified as positive and negative static stability only
2- All answers are correct
3- Static stability considers the resulting motion of aircraft
4- Static stability is the initial response of an aircraft
Static stability is the initial response of an aircraft
STATIC STABILITY:
= Initial response after disturbance
-Positive –> Returns to original attitude
-Neutral –> Retains disturbed attitude
-Negative –> Worsens disturbed attitude
DYNAMIC STABILITY:
= Resulting motion over time
-Positive –> oscillations dampen out over time
-Neutral –> Amplitude of oscillations remains constant
-Negative –> Amplitude of oscillations increases over time
What is the purpose of the horizontal stabiliser with respect to aircraft stability?
1- The horizontal stabiliser provides stabilising pitching moment
2- The horizontal stabiliser provides destabilising pitching moment
3- The horizontal stabiliser has no effect on stability
4- The horizontal stabiliser increases the aircraft CG movement
The horizontal stabiliser provides stabilising pitching moment
Which opposes the wing’s destabilizing pitch down moment
What is the distance between the Neutral point and the aircraft CG in straight, level flight called?
1- CG aft limit
2- Manoeuvre margin
3- Static margin
4- CG forward limit
Static margin
STATIC MARGIN:
= Distance between CG and neutral point ( % MAC) –> Higher static margin = aircraft more stable and less maneuvrable
NEUTRAL POINT:
= Point where destabilizing wing moment and stabilizing stabilizer moment are equal!
From front to aft: (“CiNEMA”) –> CG –> NEutral point –> MAneuvre point
CG aft = Increase maneuvrability; Decrease stability (wing destabiliting moment > stabilizer stabilizing moment)
CG forward = Decrease maneuvrability; Increase stability ( stabilizer stabilizing moment > wing destabiliting moment)
Which of the following statements about the trimmed flight are correct? 1. The weight is balanced by the lift
2. The drag is balanced by the thrust 3. Aerodynamic moments about the aircraft CG is zero.
1- Only 1 and 2 are correct
2- 1, 2 and 3 are correct
3- Only 2 and 3 are correct
4- Only 1 and 3 are correct
1, 2 and 3 are correct
Which stabilities of the aircraft are coupled?
1- Directional and longitudinal stability
2- Directional and lateral stability
3- Lateral and longitudinal stability
4- Longitudinal, directional and lateral stability
Directional and lateral stability
Directional (yaw) –> Spiral dive
Lateral (roll) –> Dutch roll
Which type of static stability will make the aircraft retain the disturbed attitude?
1- Negative static stability
2- Positive static stability
3- Neutral static stability
4- Dynamic stability
Neutral static stability
STATIC STABILITY:
= Initial response after disturbance
-Positive –> Returns to original attitude
-Neutral –> Retains disturbed attitude
-Negative –> Worsens disturbed attitude
DYNAMIC STABILITY:
= Resulting motion over time
-Positive –> oscillations dampen out over time
-Neutral –> Amplitude of oscillations remains constant
-Negative –> Amplitude of oscillations increases over time
Which stability considers the resulting motion of an aircraft over time? Select the most complete answer
1- Static stability
2- Dynamic stability
3- All answers are correct
4- No other answer is correct
Dynamic stability
STATIC STABILITY:
= Initial response after disturbance
-Positive –> Returns to original attitude
-Neutral –> Retains disturbed attitude
-Negative –> Worsens disturbed attitude
DYNAMIC STABILITY:
= Resulting motion over time
-Positive –> oscillations dampen out over time
-Neutral –> Amplitude of oscillations remains constant
-Negative –> Amplitude of oscillations increases over time
Which of the following statement regarding the behaviour of an aircraft in a spiral dive is/are correct? Select the most complete answer.
1- All answers are correct
2- The bank angle of the aircraft increases
3- The altitude of the aircraft decreases
4- The nose low-pitch attitude increases
All answers are correct
SPIRAL DIVE: (“Spain Yawkes :/ “)
-Aperiodic motion
-Strong directional (yaw) stability
-Weak lateral (roll) stability
-Stable dive = wings level
-Neutral dive = Maintains bankg angle
-Unstable (spiral divergence) = Bank angle increases
DUTCH ROLL: (“Dutch rocks n’ roll :D”)
-Periodic motion
-Strong lateral (roll) stability
-Weak directional (yaw) stability
-More likely at thigh altitude /mach
Which of the following statement is true about long period oscillation?
1- The pilot cannot easily control this motion
2- Long period oscillation is a progressive exchange of kinetic and potential energy
3- Specific aerodynamic provisions are required to counteract long period oscillation
4- Long period oscillation is one of the basic modes of static stability
Long period oscillation is a progressive exchange of kinetic and potential energy
PHUGOID (LONG-PERIOD OSCILLATION):
-1-2 min
-Weak damping
-High airspeed variation
-High altitude variation
-Slow AoA changes
SHORT-PERIOD OSCILLATION:
-1-2s
-Strong damping
-Constant airspeed
-Constant altitude
-Rapid AoA changes
What happens if the manoeuvrability of an aircraft increases?
1- Stability decreases
2- Stability also increases
3- Stability neither increase nor decrease
4- Pilot input to control column increases
Stability decreases
Stability opposed maneuvrability!
STATIC MARGIN:
= Distance between CG and neutral point ( % MAC) –> Higher static margin = aircraft more stable and less maneuvrable
NEUTRAL POINT:
= Point where destabilizing wing moment and stabilizing stabilizer moment are equal!
From front to aft: (“CiNEMA”) –> CG –> NEutral point –> MAneuvre point
CG aft = Increase maneuvrability; Decrease stability (wing destabiliting moment > stabilizer stabilizing moment)
CG forward = Decrease maneuvrability; Increase stability ( stabilizer stabilizing moment > wing destabiliting moment)
How does the required download on the horizontal stabiliser change with the CG moving forward?
1- It increases
2- It decreases
3- It doesn’t change
4- It decreases or increases, depending on the airspeed
It increases
Forward CG limit is determined by amount of pitch control available –> If CG exceeds forward limit, the tailplane may fail to produce enough downforce (nose-up pitching moment) to counter-act the wing’s nose down moment!
If the control wheel is turned to the right_____, .
1- the right aileron is deflected up and the left aileron is deflected up
2- the right aileron is deflected down and the left aileron is deflected down
3- the right aileron is deflected up and the left aileron is deflected down
4- the right aileron is deflected down and the left aileron is deflected up
the right aileron is deflected up and the left aileron is deflected down
AILERONS:
-provide lateral control by producing different amount of lift on both wings
-Aircraft turns towards the side of the upward deflected aileron due to less lift on that wing
-Upgoing aileron also produces less drag –> adverse yaw = yaw in opposite direction of turn
-Aileron defflection does NOT give a specific roll displacement but rather a given roll rate! –> higher wingspan = lower roll rate
How can the adverse yaw be reduced? Select the most complete answer.
1- By using roll spoilers
2- By Frise ailerons
3- All answers are correct
4- By the differential ailerons
All answers are correct
During roll, the upgoing aileron also produces less drag –> adverse yaw = yaw in opposite direction of turn
The horizontal stabiliser positioned at neutral at cruising speed and with normal CG position ____ .
1- will not produce any load
2- will produce an upload
3- will produce a download
4- will produce download or upload depending on the speed
will produce a download
Horizontal stabilizer produced a download force leading to a nose pitch up moment to counter-act the wings’ nose pitch down moment!
Which statement about the effect of using a trim tab on the hinge moment is true?
1- The trim tab decreases the hinge moment
2- The trim tab does not affect the hinge moment
3- The trim tab increases the hinge moment
4- The trim tab balances the hinge moment
The trim tab balances the hinge moment
Trim tab = balances hinge moment
Balance tab = decreases hinge moment
Adjustable trim tab = On rudder and elevator –> fitted to trailling edge of control surface, that moves in opposite direction
Fixed trim tab = On ailerons –> adjusted only on the ground
**The rotation about the lateral axis is known as _____ **.
1- yawing
2- pitching
3- banking
4- rolling
pitching
All the axes of the aeroplane must pass through ____.
1- the Centre of Gravity
2- the Centre of Pressure
3- the Aerodynamic Centre
4- the geometric centre of the fuselage
the Centre of Gravity
How does the wingspan influence the roll rate for a given aileron deflection?
1- The greater the wingspan the lower the roll rate
2- The greater the wingspan the greater the roll rate
3- It does not influence the roll rate
4- Greater wingspan increases the roll rate, but only if the aeroplane is laterally unstable
The greater the wingspan the lower the roll rate
AILERONS:
-provide lateral control by producing different amount of lift on both wings
-Aircraft turns towards the side of the upward deflected aileron due to less lift on that wing
-Upgoing aileron also produces less drag –> adverse yaw = yaw in opposite direction of turn
-Aileron defflection does NOT give a specific roll displacement but rather a given ROLL RATE! –> higher wingspan = lower roll rate
Which is the correct definition of the longitudinal axis?
1- The axis directed forward, along the fuselage reference line, passing through CP
2- The axis directed forward, along the fuselage reference line, passing through CG
3- The axis parallel to the line connecting wingtips, passing through CG
4- The axis parallel to the line connecting wingtips, passing through CP
The axis directed forward, along the fuselage reference line, passing through CG
The angle of the rudder deflection ____.
1- corresponds to a specific yaw displacement
2- corresponds to a specific yaw rate change
3- does not correspond to any specific yaw displacement or rate
4- is not limited
corresponds to a specific yaw displacement
Angle of rudder or elevator defflection corresponds to a specfic pitch and yaw displacement
While….
Angle of aileron deflection corresponds to a given roll rate!
What is true about the never exceed speed VNE? Select the most complete answer.
1- VNE is set below the VD to enable the upset recovery
2- VNE is relevant for small aircraft
3- All answers are correct
4- VNE exceedance may result in structural damage or failure
All answers are correct
VS1 = Stall speed –> Minimum speed at which aircraft is controllable
Va = Maneuvering speed –> Va = VS1 x (√n); Va < Vc Max speed for control surface full deflection. Depends on mass and pressure altitude.
Vb = Design speed for max gust intensity –> 66ft/s gust. Flying through turbulence at Vb provides max protectiong from damage
Vc = Design cruising speed –> Used to assess strenght requirements in cruise. 50ft/s gust
Vd = Design Dive speed –> Highest speed the aircraft is designed to achieve. 25 ft/s gust
Vra = Speed Rough Air –> recommended turbulence penetration speed
Vne = Never Exceed speed –> <0.9*Vd to enable upset recovery; relevant to small aircraft; marked as red line in ASI;
Vfe = Flaps Extended speed–> Max speed w/ flaps extended; end of white arc on ASI
How is the ultimate load defined?
1- The ultimate load is the maximum load that doesn’t result in critical failure of the structure
2- The ultimate load is the maximum load that is expected during the operations
3- The ultimate load is the load that leads to the failure of the structure
4- The ultimate load is the load for the maximum landing weight
The ultimate load is the load that leads to the failure of the structure
Ultimate load = Load that leads to failure of the structure
Limit load = Max load expected during operations
Factor of safety = ultimate load / limit load; 1,5x load factor!
How is the equivalent airspeed (EAS) defined?
1- EAS is the airspeed of the aircraft relative to the airmass in which it is flying at ISA conditions
2- EAS is the airspeed of the aircraft relative to the airmass in which it is flying
3- None of the answers is correct
4- EAS is an airspeed at sea level ISA conditions which generates the same total pressure at TAS at an altitude at which the aircraft is flying
None of the answers is correct
Equivalent Air Speed
= Airspeed that generates same dynamic pressure as TAS at an altitude which the aircraft is flying
-Used to: Predict aerodynamic load and Predict stalling
= EAS = TAS * √(actual density / std sea lvl density)
How does the wing loading affect the increase in load factor due to the gust?
1- High wing loading results in a lower increase of load factor due to the gust
2- High wing loading results in a greater increase of load factor due to the gust
3- Low wing loading results in a lower increase of load factor due to the gust
4- The wing loading does not affect the increase in load factor due to the gust
High wing loading results in a lower increase of load factor due to the gust
Gust load factor decreases when:
-AoA increases
-altitude increases
-Mass increases
-Wing load factor increases
-Speed decreases
-Lower wing area
-Lower aspect ratio
How to prevent the flutter of the ailerons? Select the most complete answer.
1- By making the ailerons irreversible
2- All answers are correct
3- By attaching a mass before the hinge line
4- By moving the CG to, or ahead of the hinge line
All answers are correct
FLUTTER:
= Quick uncontrolled oscillations of the surface
= Most dangerous effect of aeroelasticity
- Dependent on IAS
-Caused by:
-Bending + torsion of wing
-Aeroelastic coupling
-Cyclic deformations
-Prevented by:
-Wing CG ahead of torsional axis
-Increase wing stiffness (by placing leading edge spar)
-Wing mounted engines ahead of wing CG
-Mass balance of control surface (to move CG ahead of hinge line)
-Fully powered controls (irreversible, w/o manual override)
What will be the design manoeuvring speed if the VS = 50 kt and n = 6?
1- 122 kt
2- 137 m/s
3- 122 km/h
4- None of the answers is correct
122 kt
VS1 = Stall speed –> Minimum speed at which aircraft is controllable
Va = Maneuvering speed –> Va = VS1 x (√n); Va < Vc Max speed for control surface full deflection. Depends on mass and pressure altitude.
Vb = Design speed for max gust intensity –> 66ft/s vertical gust. Flying through turbulence at Vb provides max protectiong from damage
Vc = Design cruising speed –> Used to assess strenght requirements in cruise. 50ft/s vertical gust
Vd = Design Dive speed –> Highest speed the aircraft is designed to achieve. 25 ft/s vertical gust
Vra = Speed Rough Air –> recommended turbulence penetration speed
Vne = Never Exceed speed –> <0.9*Vd to enable upset recovery; relevant to small aircraft; marked as red line in ASI;
Vfe = Flaps Extended speed–> Max speed w/ flaps extended; end of white arc on ASI
What type of gusts are considered during aircraft design?
1- Horizontal gusts of different speeds
2- Vertical gusts of different speeds
3- Gusts of the same speed at different angles
4- None of the answers is correct
Vertical gusts of different speeds
VS1 = Stall speed –> Minimum speed at which aircraft is controllable
Va = Maneuvering speed –> Va = VS1 x (√n); Va < Vc Max speed for control surface full deflection. Depends on mass and pressure altitude.
Vb = Design speed for max gust intensity –> 66ft/s vertical gust. Flying through turbulence at Vb provides max protectiong from damage
Vc = Design cruising speed –> Used to assess strenght requirements in cruise. 50ft/s vertical gust
Vd = Design Dive speed –> Highest speed the aircraft is designed to achieve. 25 ft/s vertical gust
Vra = Speed Rough Air –> recommended turbulence penetration speed
Vne = Never Exceed speed –> <0.9*Vd to enable upset recovery; relevant to small aircraft; marked as red line in ASI;
Vfe = Flaps Extended speed–> Max speed w/ flaps extended; end of white arc on ASI
What is true about the never exceed speed VNE? Select the most complete answer.
1- VNE is relevant for small aircraft
2- VNE is marked as a red line on the airspeed indicator
3- VNE is set below the VD to enable the upset recovery
4- All answers are correct
All answers are correct
VS1 = Stall speed –> Minimum speed at which aircraft is controllable
Va = Maneuvering speed –> Va = VS1 x (√n); Va < Vc Max speed for control surface full deflection. Depends on mass and pressure altitude.
Vb = Design speed for max gust intensity –> 66ft/s vertical gust. Flying through turbulence at Vb provides max protectiong from damage
Vc = Design cruising speed –> Used to assess strenght requirements in cruise. 50ft/s vertical gust
Vd = Design Dive speed –> Highest speed the aircraft is designed to achieve. 25 ft/s vertical gust
Vra = Speed Rough Air –> recommended turbulence penetration speed
Vne = Never Exceed speed –> <0.9*Vd to enable upset recovery; relevant to small aircraft; marked as red line in ASI;
Vfe = Flaps Extended speed–> Max speed w/ flaps extended; end of white arc on ASI
How should be the aircraft designed?
1- To make the natural frequencies occur at speeds beyond VD
2- To make the natural frequencies occur at speeds below VD
3- To make the natural frequencies occur at speeds below VC
4- To make the natural frequencies occur at speeds below VB
To make the natural frequencies occur at speeds beyond VD
What will be the design manoeuvring speed if the VS = 170 kt and n = 2.5?
1- 126 m/s
2- 567 km/h
3- 453 km/h
4- 269 kt
269 kt
n = load factor = Lift / Weight
VS1 = Stall speed –> Minimum speed at which aircraft is controllable
Va = Maneuvering speed –> Va = VS1 x (√n); Va < Vc Max speed for control surface full deflection. Depends on mass and pressure altitude.
Vb = Design speed for max gust intensity –> 66ft/s vertical gust. Flying through turbulence at Vb provides max protectiong from damage
Vc = Design cruising speed –> Used to assess strenght requirements in cruise. 50ft/s vertical gust
Vd = Design Dive speed –> Highest speed the aircraft is designed to achieve. 25 ft/s vertical gust
Vra = Speed Rough Air –> recommended turbulence penetration speed
Vne = Never Exceed speed –> <0.9*Vd to enable upset recovery; relevant to small aircraft; marked as red line in ASI;
Vfe = Flaps Extended speed–> Max speed w/ flaps extended; end of white arc on ASI
What are the benefits of using constant speed propellers? Select the most complete answer.
1- All answers are correct
2- High efficiency can be obtained over a wider range of TAS
3- Improved performance for the take-off
4- Improved performance for the climb
All answers are correct
PROPELLERS:
1) Fixed pitch prop:
-No moving parts
-AoA is set during manufacturing
-RPM depends on engine speed
2) Variable pitch prop:
2.1. Adjustable pitch prop –> on the ground
2.2. Two pitch prop –> 2 settings (fine or coarse pitch)
2.3. Constant speed prop:
-Modern aircraft
-Controlled automatically to keep selected RPM by changing blade angle
-Increase airspeed = same RPM = decrease AoA (fine pitch) = Decrease thrust = Decrease torque
-Decrease airspeed = same RPM = increase AoA (coarse pitch) = increase thrust = increase torque
What will the torque reaction do in the aircraft equipped with a clockwise rotating propeller?
1- None of the answers is correct
2- The torque reaction will make the aircraft roll to the right
3- The torque reaction will make the aircraft roll to the left
4- The torque reaction will make the aircraft yaw to the right
The torque reaction will make the aircraft roll to the left
TORQUE REACTION:
-Propeller rotates clock.wise, so torque reaction will be anti-clockwise
-Greatest torque reaction = T/O + high power setting + Low airspeed
–> during flight aircraft ROLLS TO THE LEFT
–> on the ground aircraft YAWS TO THE LEFT
How is the angle of attack defined?
1- The angle between the blade chord and the relative airflow
2- The angle between the blade chord and the plane of rotation
3- The angle between the actual path of the propeller and the plane of rotation
4- None of the answers is correct
The angle between the blade chord and the relative airflow
AoA:
= Angle between blade chord line and relative airflow
-Depends on RPM + true airspeed
BLADE ANGLE (pitch):
= Angle between blade chord line and plane of rotation
-Decreases from root to tip - blade twist - (this change in blade angle along the blade keeps an uniform AoA)
-Determines the geometric pitch (=distance the prop would move forward in 1 RPM at zero AoA)
When a force directed upwards is applied to the horizontal stabilizer in an aircraft with an anti-clockwise rotating propeller which precession moment occurs?
1- The left yawing moment
2- None of the answers is correct
3- The pitching down moment
4- The pitching up moment
None of the answers is correct
Correct would be: yaw to the right
GYROSCOPIC PRECESSION:
= Force is felt at 90º from applied force
- Induced by PITCH and YAW
- On a clockwise prop:
-Pitch up = yaw to right
-Pitch down = yaw to left
-Yaw to right = pitch up
-Yaw to left = pitch down
Note: Same as car blinkers “up is right, down is left”
P-FACTOR (asymmetric prop blade effect);
= induced by inclination of prop axis to relative airflow
-Highest when full power + low airspeed
-Blade that is going down –> higher AoA –> more thrust
-Blade that is going up –> lower AoA –> less thrust
-Generates LEFT YAW in a nose-up position!
SPIRAL SLIPSTREAM:
= Rotating prop produces airflow that moves backwards around the aircraft ultimately acting on the vertical stabilizer, producing LEFT YAW.
-Depends on throttle and RPM
-reduced by:
-Tab on the rudder
-Engline thrust line slighty deviated to the right
What is the blade twist?
1- The chord line is curved
2- None of the answers is correct
3- The change of the aerofoil along the propeller span
4- The change of the blade angle along the propeller span
The change of the blade angle along the propeller span
AoA:
= Angle between blade chord line and relative airflow
-Depends on RPM + true airspeed
BLADE ANGLE (pitch):
= Angle between blade chord line and plane of rotation
-Decreases from root to tip - blade twist - (this change in blade angle along the blade keeps an uniform AoA)
-Determines the geometric pitch (=distance the prop would move forward in 1 RPM at zero AoA)
When does the gyroscopic effect occur? Select the most complete answer.
1- All answers are correct
2- While yawing to the left
3- While pitching up
4- While pitching down
All answers are correct
Yaw and Pitch
GYROSCOPIC PRECESSION:
= Force is felt at 90º from applied force
- Induced by PITCH and YAW
- On a clockwise prop:
-Pitch up = yaw to right
-Pitch down = yaw to left
-Yaw to right = pitch up
-Yaw to left = pitch down
Note: Same as car blinkers “up is right, down is left”
P-FACTOR (asymmetric prop blade effect);
= induced by inclination of prop axis to relative airflow
-Highest when full power + low airspeed
-Blade that is going down –> higher AoA –> more thrust
-Blade that is going up –> lower AoA –> less thrust
-Generates LEFT YAW in a nose-up position!
SPIRAL SLIPSTREAM:
= Rotating prop produces airflow that moves backwards around the aircraft ultimately acting on the vertical stabilizer, producing LEFT YAW.
-Depends on throttle and RPM
-reduced by:
-Tab on the rudder
-Engline thrust line slighty deviated to the right
-Slight offset of the fin
How to reduce the spiral slipstream effect? Select the most complete answer.
1- By engine thrust line slightly inclined to the right in clockwise-rotating propeller
2- By a small tab on the rudder
3- All answers are correct
4- By slight offset of the fin
All answers are correct
GYROSCOPIC PRECESSION:
= Force is felt at 90º from applied force
- Induced by PITCH and YAW
- On a clockwise prop:
-Pitch up = yaw to right
-Pitch down = yaw to left
-Yaw to right = pitch up
-Yaw to left = pitch down
Note: Same as car blinkers “up is right, down is left”
P-FACTOR (asymmetric prop blade effect);
= induced by inclination of prop axis to relative airflow
-Highest when full power + low airspeed
-Blade that is going down –> higher AoA –> more thrust
-Blade that is going up –> lower AoA –> less thrust
-Generates LEFT YAW in a nose-up position!
SPIRAL SLIPSTREAM:
= Rotating prop produces airflow that moves backwards around the aircraft ultimately acting on the vertical stabilizer, producing LEFT YAW.
-Depends on throttle and RPM
-reduced by:
-Tab on the rudder
-Engline thrust line slighty deviated to the right
-Slight offset of the fin
What moment is generated due to the p-factor in a clockwise-rotating propeller in a nose-up position?
1- Right yawing moment
2- Left yawing moment
3- Pitching down moment
4- Pitching up moment
Left yawing moment
GYROSCOPIC PRECESSION:
= Force is felt at 90º from applied force
- Induced by PITCH and YAW
- On a clockwise prop:
-Pitch up = yaw to right
-Pitch down = yaw to left
-Yaw to right = pitch up
-Yaw to left = pitch down
Note: Same as car blinkers “up is right, down is left”
P-FACTOR (asymmetric prop blade effect);
= induced by inclination of prop axis to relative airflow
-Highest when full power + low airspeed
-Blade that is going down –> higher AoA –> more thrust
-Blade that is going up –> lower AoA –> less thrust
-Generates LEFT YAW in a nose-up position!
SPIRAL SLIPSTREAM:
= Rotating prop produces airflow that moves backwards around the aircraft ultimately acting on the vertical stabilizer, producing LEFT YAW.
-Depends on throttle and RPM
-reduced by:
-Tab on the rudder
-Engline thrust line slighty deviated to the right
-Slight offset of the fin
What happens when the propeller is in the windmilling position?
1- The propeller in the windmilling position generates thrust and the torque makes the propeller turn
2- The propeller in the windmilling position generates drag instead of thrust and the torque makes the propeller turn
3- The propeller in the windmilling position generates thrust and the torque is the reaction to the propeller being rotated
4- None of the answers is correct
The propeller in the windmilling position generates drag instead of thrust and the torque makes the propeller turn
FEATHERED PROP:
-Blade angle = 90º
-Zero lift AoA
-NO torque! –> prop does not rotate
-LESS DRAG
NON-ROTATING PROP:
-Less drag
WINDMILLING PROP:
-MORE DRAG!
-Decreased (fine pitch)
-Still produces torque which rotates the propeller
What is the skidding turn?
1- A turn in which the ball moves to the same side as the aircraft’s nose
2- A turn in which the aircraft climbs
3- A turn in which the ball remains within the lines
4- A turn in which the ball moves to the opposite side than the aircraft’s nose
A turn in which the ball moves to the opposite side than the aircraft’s nose
Slip = too little ruder –> Ball on the SAME side
Skid = too much rudder –> Ball on the OPPOSITE side
What is the turn radius for an aircraft flying at 50 m/s and a bank angle equal to 45⁰?
1- 275 m
2- 245 m
3- 235 m
4- 255 m
255 m
R = V^2 / (g*tanθ)
How is the flight path angle defined?
1- An angle between the flight path and the centreline of the aircraft
2- An angle between the flight path and the horizontal line
3- An angle between the flight path and the direction of the oncoming air
4- None of the answers is correct
An angle between the flight path and the horizontal line
Aircraft AoA = Angle between flight path and aircraft longitudinal axis
Flight path angle = angle between the flight path and the horizontal line
Pitch attitude = AoA + flight path angle = Angle between aircraft longitudinal axis and horizontal line
What is the turn radius for an aircraft flying at 100 m/s and a bank angle equal to 30⁰?
1- 1777 m
2- 1766 m
3- 1555 m
4- 1888 m
1766 m
R = V^2 / (g*tanθ)
What happens with the glide distance when flaps are extended?
1- It depends on the type of flaps
2- Glide distance is increased
3- Glide distance is reduced
4- Extended flaps have no influence on glide distance
Glide distance is reduced
What is the turn radius for an aircraft flying at 100 m/s and a bank angle equal to 60⁰?
1- 599 m
2- 573 m
3- 588 m
4- 557 m
588 m
R = V^2 / (g*tanθ)
What is a steady flight? Select the most complete answer.
1- The flight with no acceleration in any direction
2- All answers are correct
3- The flight with all forces acting on the aircraft balanced
4- The flight with all moments acting on the aircraft balanced
All answers are correct
What happens when the bank angle is increased?
1- A higher lift force is required so the angle of attack is decreased
2- A higher lift force is required so the angle of attack is increased
3- A lower lift force is required so the angle of attack is decreased
4- A lower lift force is required so the angle of attack is increased
A higher lift force is required so the angle of attack is increased
To maintain speed and altitude –> Increase thrust and AoA
How to calculate the turn radius for a given bank angle? V – velocity, g – gravitational acceleration, φ – bank angle
1- Turn radius = (g*tan φ)/V
2- Turn radius = V/(g*tan φ)
3- Turn radius = (g*tan φ)/V^2
4- Turn radius = V^2/(g*tan φ)
Turn radius = V^2/(g*tan φ)
What factors affect the radius of the steady, coordinated turn? Select the most complete answer.
1- Airspeed
2- All answers are correct
3- Angle of attack
4- Aircraft configuration
Airspeed
Radius of turn is determined solely by airspeed
What happens when the bank angle is increased?
1- Increased bank angle increases the drag
2- Increased bank angle decreases the drag
3- Increased bank angle has no influence on the drag
4- Increased bank angle increases total drag but decrease the induced drag
Increased bank angle increases the drag
* What happens when the propeller is in the windmilling position?*
1- None of the answers is correct
2- The propeller in the windmilling position generates thrust and the torque makes the propeller turn
3- The propeller in the windmilling position generates thrust and the torque is the reaction to the propeller being rotated
4- The propeller in the windmilling position generates drag instead of thrust and the torque is the reaction to the propeller being rotated
None of the answers is correct
Correct would be: “The propeller in the windmilling position generates drag instead of thrust and the torque makes the propeller turn”
When the left yaw is applied to the aircraft with a clockwise rotating propeller which precession moment occurs?
1- The pitching up moment
2- The pitching down moment
3- The left yawing moment
4- The right yawing moment
The pitching up moment
Gyroscopic precession = Applied force results in effective force in opposite surface and then the resultant force felt at 90º (according to the turn direction of the propeller)
How to minimize the drag of the failed engine?
1- By turning the propeller to the windmilling position
2- By turning the propeller to the feathering position
3- By turning the propeller to the ground fine pitch position
4- By turning the propeller to the reverse pitch position
By turning the propeller to the feathering position
FEATHERED PROP:
-Blade angle = 90º
-Zero lift AoA
-NO torque! –> prop does not rotate
-LESS DRAG
NON-ROTATING PROP:
-Less drag
WINDMILLING PROP:
-MORE DRAG!
-Decreased (fine pitch)
-Still produces torque which rotates the propeller
How to delay the wing flutter to a higher speed?
1- By mounting the engines on pylons under the wing behind the leading edge
2- By mounting the engines on pylons over the wing before the leading edge
3- None of the answers is correct
4- By mounting the engines on pylons over the wing behind the leading edge
None of the answers is correct
Correct would be: “By mounting the engines on pylons UNDER the wing BEFORE the leading edge”
* How to prevent the flutter of the ailerons? Select the most complete answer.*
1- By making the ailerons irreversible
2- All answers are correct
3- By attaching a mass before the hinge line
4- By moving the CG to, or ahead of the hinge line
All answers are correct
What is the airspeed caution range? Select the most complete answer.
1- The range between VNO and VNE
2- The range in which it is allowed to fly only in smooth air and with caution
3- The yellow arc on the airspeed indicator
4- All answers are correct
All answers are correct
How can the forces on the cockpit controls be reduced? Select the most complete answer.
1- By using balance tabs
2- By using anti-balance tabs
3- By using trim tabs
4- All answers are correct
By using balance tabs
Deflecting the aileron downwards ____ .
1- increases lift force generated on that wing
2- decreases lift force generated on that wing
3- does not change the lift force generated on that wing
4- is only possible in an emergency
increases lift force generated on that wing
AILERONS:
-provide lateral controlby producing different amounts of ligt on both wings
-Aircraft turns towards the side of the ailerons that is raised due to less lift on that wing!
-The upgoing aileron also produces less drag.
The bank angle is the angle ____ .
1- between the aircraft’s lateral axis and the horizon
2- between the aircraft’s lateral axis and the relative airflow
3- between the aircraft’s longitudinal axis and the horizon
4- between the aircraft’s normal axis and the horizon
between the aircraft’s lateral axis and the horizon
turn radius = V^2 / (g*tanθ)
or
tanθ = V^2 / (g*turn radius)
What is the requirement of an aircraft to be dynamically stable?
1- The aircraft should be statically stable
2- The aircraft should be highly manoeuvrable
3- The aircraft should have a small CG range
4- The aircraft should have an effective elevator
The aircraft should be statically stable
Which is the correct definition of the longitudinal axis?
1- The axis directed forward, along the fuselage reference line, passing through CP
2- The axis directed forward, along the fuselage reference line, passing through CG
3- The axis parallel to the line connecting wingtips, passing through CG
4- The axis parallel to the line connecting wingtips, passing through CP
The axis directed forward, along the fuselage reference line, passing through CG
An aircraft that exhibits undamped oscillations will possess ____ .
1- positive static stability and neutral dynamic stability
2- negative static stability and neutral dynamic stability
3- neutral static stability and positive dynamic stability
4- neutral static stability and negative dynamic stability
positive static stability and neutral dynamic stability
Non-oscillatory modes (aperiodic):
- SUBSIDENCE = positive static + positive dynamic
- PURE NEUTRAL STABILITY = neutral static + neutral dynamic
- DIVERGENCE = negative stative + negative dynamic
Oscillatory modes (periodic):
-DAMPED oscillations –> Aircraft periodically returns to initial state = positive static + positive dynamic
-UNDAMPED oscillations –> Aircraft continues to oscillate around its initial state = positive static + neutral dynamic
DIVERGENT oscillations –> aircarft periodically drifts away from its initial state = positive static + negative dynamic
What are the 3 phases of the spin?
1- Incipient spin, developed spin, spin recovery
2- Incoming spin, developing spin, spin recovery
3- Accelerating spin, developed spin, spin recognition
4- Accelerating spin, developing spin, spin recovery
Incipient spin, developed spin, spin recovery
SPIN:
-Always preceeded by stall
-Both wings are stalled, but one more than the other (different AoA)
-In a spin, the aeroplane descends in a rotational movement
-Turn indicator shows direction of rotation
-Slip/skid ball is unreliable
Factors causing spin:
-Uncoordinated maneuvers
-Center of gravity lateral displacement
-Abrupt control inputs at high AoA
Spin phases:
1- Incipient
2- Developed
3- Recovery –> decrease power to idle –> Neutral ailerons –> Full opposite rudder –> Pitch down (yoke forward)
How does a forward position of the Centre of Gravity (CG) influence the stalling speed?
1- With a forward CG, the horizontal stabiliser needs to generate more downforce, which reduces the overall lift and increases stalling speed
2- With a forward CG, the horizontal stabiliser needs to generate less downforce, which increases the overall lift and reduces stalling speed
3- With a forward CG, the wing can achieve a higher Angle of Attack, which reduces the stalling speed
4- With a forward CG, the wing can achieve a lower Angle of Attack, which increases the stalling speed
With a forward CG, the horizontal stabiliser needs to generate more downforce, which reduces the overall lift and increases stalling speed
Which are the typical ice build-up locations? Select the most complete answer.
1- Leading edges of the wings and stabilisers
2- Landing gear
3- Engines outlets
4- All answers are correct
Leading edges of the wings and stabilisers
Compared to trailing edge flaps, leading edge devices like Slots…
reduce the critical angle of attack at a given speed.
allow higher speeds at take-off and landing.
produce less drag while allowing a higher angle of attack.
increase the camber and allow a lower angle of attack.
produce less drag while allowing a higher angle of attack.
Stabilization around the lateral axis during cruise is achieved by the…
horizontal stabilizer.
airlerons.
wing flaps.
vertical rudder.
horizontal stabilizer
Normal (vertical) axis = rudder
Longitudinal axis = ailerons
Horizontal axis = horizontal stabilizer
Flying with speeds higher than the never-exceed-speed (vNE)
may result in…
too high total pressure resulting in an unusable airspeed indicator.
flutter and mechanically damaging the wings.
an increased lift-to-drag ratio and a better glide angle.
reduced drag with increased control forces.
flutter and mechanically damaging the wings.
What effects typically result from propeller icing?
Reduced power output, decreasing RPM.
Increased power output, decreasing RPM.
Increased power output, increasing RPM.
Reduced power output, increasing RPM.
Reduced power output, decreasing RPM.
**During a straight and steady climb, which force acts addionally, and in the same direction as the drag force, resulting in more power required for climb than for horizontal flight? **
A component of the weight force along the rearward flight path.
The vertical component of the weight force.
A component of the thrust along the rearward flightpath.
A component of the lift force along the forward flightpath.
A component of the weight force along the rearward flight path
The static pressure of gases work…
only vertical to the flow direction.
only in the direction of the total pressure.
in all directions.
only in flow direction.
in all directions
**Bernoulli’s equation for frictionless, incompressible gases states that… **
static pressure = total pressure + dynamic pressure.
total pressure = dynamic pressure - static pressure.
dynamic pressure = total pressure + static pressure.
total pressure = dynamic pressure + static pressure.
total pressure = dynamic pressure + static pressure
Dynamic pressure = Total pressure - Static pressure
If surrounded by airflow (v>0), any arbitrarily shaped body produces…
lift without drag.
drag and lift.
constant drag at any speed.
drag.
drag
All aerodynamic forces can be considered to act on a single point.
This point is called…
center of gravity.
center of pressure.
lift point.
transition point.
center of pressure
Center of gravity = all aircraft axes pass through it
Transition point = region of the boundary layer where flow ceases to be laminar and starts being turbulent
The center of pressure is the theoretical point of origin of…
only the resulting total drag.
all aerodynamic forces of the profile.
gravity forces of the profile.
gravity and aerodynamic forces.
all aerodynamic forces of the profile
What is the distance between the leading and trailing edge of the wing?
chord line.
chord.
angle of attack.
profile thickness.
chord
What is the line which lies halfway between the upper surface and lower surface of the airfoil and intersects the chord line at the leading and trailing edges?
chord.
thickness.
camber line.
chord line.
camber line
**The angle of attack is the angle between…
**
the undisturbed airflow and the longitudinal axis of an aeroplane.
the chord line and the longitudinal axis of an aeroplane.
the chord line and the oncoming airflow.
the wing and the fuselage of an aeroplane.
the chord line and the oncoming airflow
The ratio of span and mean chord length is referred to as…
trapezium shape.
tapering.
aspect ratio.
wing sweep.
aspect ratio
Low aspect ratio = short wing
High aspect ratio = long wing
What is the point where laminar boundary layer turns into turbulent boundary layer?
Separation point
Center of pressure
Stagnation point
Transition point
Transition point
BOUNDARY LAYER:
= Layer where airflow velocity changes from zero at the aerofoil’s surface to the value o undisturbed airflow
-Boundary layer thickness = From surface to 99% velocity of undisturbed airflow (increases w/ distance from leading edge)
-Transition point = Laminar boundary layer turns into turbulent boundary layer
-LAMINAR boundary layer –> Thinner; less energy; less friction drag; more susceptible to flow separation
-TURBULENT boundary layer –> Thicker; more energy; more friction drag; less susceptible to flow separation
Vs
SEPARATION POINT:
= Airflow stops following the curvature of the wing and starts moving freely
-At low AoA –> Separation point is located near the trailing edge
-As AoA increases –> Separation point moves forward
What is point where airflow stops following the curvature of the wing and starts moving freely?
Center of pressure
Separation point
Transition point
Stagnation point
Separation point
SEPARATION POINT:
= Airflow stops following the curvature of the wing and starts moving freely
-At low AoA –> Separation point is located near the trailing edge
-As AoA increases –> Separation point moves forward
Vs
BOUNDARY LAYER:
= Layer where airflow velocity changes from zero at the aerofoil’s surface to the value o undisturbed airflow
-Boundary layer thickness = From surface to 99% velocity of undisturbed airflow (increases w/ distance from leading edge)
-Transition point = Laminar boundary layer turns into turbulent boundary layer
-LAMINAR boundary layer –> Thinner; less energy; less friction drag; more susceptible to flow separation
-TURBULENT boundary layer –> Thicker; more energy; more friction drag; less susceptible to flow separation
Wing tip vortex development begins during which phase of flight? (1,00 P.)
As soon as the aircraft starts moving
While setting take-off power during take-off run
While setting flaps to lower position
When lift is being generated during rotation
When lift is being generated during rotation
What is the point where the velocity is reduced to zero?
Transition point
Stagnation point
Center of pressure
Separation point
Stagnation point
Stagnation point = It is the point where the velocity is reduced to zero
Center of pressure point = It is the point where the resultant aerodynamic force acts
Mean aerodynamic chord (MAC) = It is the point where the aeroplane’s lateral axis intersects with the centre of gravity
What pattern can be found at the stagnation point?
The boundary layer starts separating on the upper surface of the profile
The laminar boundary layer changes into a turbulent boundary layer
All aerodynamic forces can be considered as attacking at this single point
Streamlines are divided into airflow above and below the profile
Streamlines are divided into airflow above and below the profile
What pressure pattern can be observed at a lift-generating wing profile at positive
angle of attack?
Low pressure is created above, higher pressure below the profile
High pressure is created above, lower pressure below the profile
Pressure above remains unchanged, higher pressure is created below the profile
Pressure below remains unchanged, lower pressure is created above the profile
Low pressure is created above, higher pressure below the profile
The position of the the center of pressure at a positively shaped profile…
moves to the leading edge while the angle of attack becomes smaller.
is located at approximately 25% of the chord, measured from the leading edge.
moves to the trailing edge while the angle of attack becomes smaller.
does not move since it is independent of the angle of attack.
moves to the trailing edge while the angle of attack becomes smaller.
Vs –> Aerodynamic center = is located at approximately 25% of the chord, measured from the leading edge.
**In which way does the position of the center of pressure move at a positively shaped profile with increasing angle of attack? **
It moves backward until reaching the critical angle of attack
It moves forward first, then backward
It moves forward until reaching the critical angle of attack
It moves to the wing tips
It moves forward until reaching the critical angle of attack
Which statement about lift and angle of attack is correct?
Too large angles of attack can lead to an exponential increase in lift
Increasing the angle of attack results in less lift being generated by the aerofoil
Increasing the angle of attack too far may result in a loss of lift and an airflow separation
Decreasing the angle of attack results in more drag being generated by the aerofoil
Increasing the angle of attack too far may result in a loss of lift and an airflow separation
Which statement about the airflow around an aerofoil is correct if the angle of attack
increases?
The stagnation point moves down
The center of pressure moves down
The center of pressure moves up
The stagnation point moves up
The stagnation point moves down
**Which statement about the airflow around an aerofoil is correct if the angle of attack
decreases? **
The center of pressure moves aft
The stagnation point remains constant
The stagnation point moves down
The center of pressure moves forward
The center of pressure moves aft
Decrease AoA:
-Center of pressure moves aft (back)
-Stagnation point moves up
Increase AoA
-Center of pressure moves fore (forward)
-Stagnation point moves down
The angle between chord line and relative airflow is?
lift angle.
angle of incidence.
angle of inclination.
angle of attack.
angle of attack
In order to improve the stall characteristics of an aircraft, the wing is twisted outwards
(the angle of incidence varies spanwise).
This is known as…
aerodynamic washout.
arrow shape.
V-form.
geometric washout.
geometric washout
Which option states a benefit of wing washout?
Structurally the wing is made more rigid against rotation
With the washout the form drag reduces at high speeds
Greater hardness because the wing can withstand more torsion forces
At high angles of attack the effectiveness of the aileron is retained as long as possible
At high angles of attack the effectiveness of the aileron is retained as long as possible
Which statement concerning the angle of attack is correct?
The angle of attack cannot be negative
Increasing the angle of attack results in decreasing lift
The angle of attack is constant throughout the flight
A too large angle of attack may result in a loss of lift
A too large angle of attack may result in a loss of lift
When increasing the airflow speed by a factor of 2 while keeping all other parameters constant, how does the parasite drag change approximately?
It decreases by a factor of 2
It increases by a factor of 2
It decreases by a factor of 4
It increases by a factor of 4
It increases by a factor of 4
The drag coefficient…
increases with increasing airspeed.
is proportional to the lift coefficient.
cannot be lower than a non-negative, minimal value.
may range from zero to an infinite positive value.
cannot be lower than a non-negative, minimal value.
****Pressure compensation on an wing occurs at the…
wing roots.
wing tips.
trailing edge.
leading edge.
wing tips
Which of the following options is likely to produce large induced drag?
Large aspect ratio
Tapered wings
Small aspect ratio
Low lift coefficients
Small aspect ratio
Which parts of an aircraft mainly affect the generation of induced drag?
the front part of the fuselage.
the wing tips.
the lower part of the gear.
the outer part of the ailerons.
the wing tips
**Where is interference drag generated? **
At the wing root
At the ailerons
At the the gear
Near the wing tips
At the wing root
Inteference drag = generated by the mixing of airflow streams between airframe components, such as the wing and the fuselage
Which curve represents the induced drag?
1- Induced drag decreases with increasing airspeed
2- Induced drag increases with increasing airspeed
3- Induced drag increases sharply with increasing airspeed
4- Induced drag initially decreases an then increases with increasing airspeed
Induced drag decreases with increasing airspeed
Pressure drag, interference drag and friction drag belong to the group of the…
induced drag.
parasite drag.
main resistance.
total drag.
parasite drag
TOTAL DRAG:
- Componentes are Induced drag + Parasite drag
= Skin friction drag + Pressure drag
INDUCED DRAG:
= Created as a result of lift (begins at aircraft rotation)
-Decreases with increasing airspeed
PRESSURE DRAG
= Form drag + Induced drag
PARASITE DRAG:
= all drag that is nto associated with production of lift
= Skin friction drag + Form drag + Interference drag
- Increases with increasing airspeed
PROFILE DRAG
= Skin friction drag + Form drag
What kind of drag is NOT part of the parasite drag?
Interference drag
Skin-friction drag
Induced drag
Form drag
Induced drag
TOTAL DRAG:
- Componentes are Induced drag + Parasite drag
= Skin friction drag + Pressure drag
INDUCED DRAG:
= Created as a result of lift (begins at aircraft rotation)
-Decreases with increasing airspeed
PRESSURE DRAG
= Form drag + Induced drag
PARASITE DRAG:
= all drag that is nto associated with production of lift
= Skin friction drag + Form drag + Interference drag
- Increases with increasing airspeed
PROFILE DRAG
= Skin friction drag + Form drag
How do induced drag and parasite drag change with increasing airspeed during a horizontal and stable cruise flight?
Induced drag decreases and parasite drag increases
Parasite drag decreases and induced drag increases
Parasite drag decreases and induced drag decreases
Induced drag increases and parasite drag increases
Induced drag decreases and parasite drag increases
TOTAL DRAG:
- Componentes are Induced drag + Parasite drag
= Skin friction drag + Pressure drag
INDUCED DRAG:
= Created as a result of lift (begins at aircraft rotation)
-Decreases with increasing airspeed
PRESSURE DRAG
= Form drag + Induced drag
PARASITE DRAG:
= all drag that is nto associated with production of lift
= Skin friction drag + Form drag + Interference drag
- Increases with increasing airspeed
PROFILE DRAG
= Skin friction drag + Form drag
Which of the listed wing shapes has the lowest induced drag?
Elliptical shape
Double trapezoidal shape
Rectangular shape
Trapezoidal shape
Elliptical shape
Which effect does a decreasing airspeed have on the induced drag during a horizontal and stable cruise flight?
The induced drag will increase
The induced drag will collapse
The induced drag will remain constant
The induced drag will slightly decrease
The induced drag will increase
TOTAL DRAG:
- Componentes are Induced drag + Parasite drag
= Skin friction drag + Pressure drag
INDUCED DRAG:
= Created as a result of lift (begins at aircraft rotation)
-Decreases with increasing airspeed
PRESSURE DRAG
= Form drag + Induced drag
PARASITE DRAG:
= all drag that is nto associated with production of lift
= Skin friction drag + Form drag + Interference drag
- Increases with increasing airspeed
PROFILE DRAG
= Skin friction drag + Form drag
Which statement about induced drag during the horizontal cruise flight is correct?
Induced drag has a minimum at a certain speed and increases at higher as well as lower speeds
Induced drag has a maximum at a certain speed and decreases at higher as well as lower speeds
Induced drag increases with increasing airspeed
Induced drag decreases with increasing airspeed
Induced drag decreases with increasing airspeed
TOTAL DRAG:
- Componentes are Induced drag + Parasite drag
= Skin friction drag + Pressure drag
INDUCED DRAG:
= Created as a result of lift (begins at aircraft rotation)
-Decreases with increasing airspeed
PRESSURE DRAG
= Form drag + Induced drag
PARASITE DRAG:
= all drag that is nto associated with production of lift
= Skin friction drag + Form drag + Interference drag
- Increases with increasing airspeed
PROFILE DRAG
= Skin friction drag + Form drag
In which mentioned situation is the total drag at its minimum?
Induced drag is twice as much as parasite drag
Parasite drag is twice as much as induced drag
Parasite drag is equal to induced drag
Induced drag is smaller than parasite drag
Parasite drag is equal to induced drag
TOTAL DRAG:
- Componentes are Induced drag + Parasite drag
= Skin friction drag + Pressure drag
INDUCED DRAG:
= Created as a result of lift (begins at aircraft rotation)
-Decreases with increasing airspeed
PRESSURE DRAG
= Form drag + Induced drag
PARASITE DRAG:
= all drag that is nto associated with production of lift
= Skin friction drag + Form drag + Interference drag
- Increases with increasing airspeed
PROFILE DRAG
= Skin friction drag + Form drag
Which kinds of drag contribute to total drag?
Form drag, skin-friction drag, interference drag
Interference drag and parasite drag
Induced drag, form drag, skin-friction drag
Induced drag and parasite drag
Induced drag and parasite drag
TOTAL DRAG:
- Componentes are Induced drag + Parasite drag
= Skin friction drag + Pressure drag
INDUCED DRAG:
= Created as a result of lift (begins at aircraft rotation)
-Decreases with increasing airspeed
PRESSURE DRAG
= Form drag + Induced drag
PARASITE DRAG:
= all drag that is nto associated with production of lift
= Skin friction drag + Form drag + Interference drag
- Increases with increasing airspeed
PROFILE DRAG
= Skin friction drag + Form drag
How do lift and drag change when approaching a stall condition?
Lift and drag decrease
Lift and drag increase
Lift decreases and drag increases
Lift increases and drag decreases
Lift decreases and drag increases
In case of a stall it is important to…
increase the bank angle and reduce the speed.
increase the angle of attack and increase the speed.
decrease the angle of attack and increase the speed.
increase the angle of attack and reduce the speed.
decrease the angle of attack and increase the speed.
During a stall, the lift…
decreases and drag increases.
increases and drag decreases.
increases and drag increases.
decreases and drag decreases.
decreases and drag increases
The critical angle of attack…
changes with increasing weight.
decreases with forward center of gravity position.
is independent of the weight.
increases with backward center of gravity position.
is independent of the weight
What leads to a decreased stall speed Vs (IAS)?
Lower altitude
Lower density
Higher load factor
Decreasing weight
Decreasing weight
**The stall warning will be activated just before reaching which speed? **
VNE
VS
VX
VR
VS
In motorplanes the stall warning is usually activated by a change of..
the center of gravity.
the transition point.
the center of pressure.
the stagnation point.
the stagnation point
How should the pilot react to an engaged stall warning?
Pull the elevator, increase power
Pull the elevator, decrease power
Push the elevator, increase power
Raise the nose to decrease airspeed
Push the elevator, increase power
Which statement regarding a spin is correct?
During recovery the ailerons should be kept neutral
Only very old aeroplanes have a risk of spinning
During recovery the ailerons should be crossed
During the spin the speed constantly increases
During recovery the ailerons should be kept neutral
**When extending the flaps for landing at constant angle of attack, in which way does the lift coefficient change far before reaching the maximum lift coefficient? **
It decreases
It is not possible to define
It increases
It remains constant
It increases
With regard to flaps, which of the following options provides a lift-increasing effect?
Decreasing the angle of attack
Increasing the aerofoil camber
Decreasing the form drag
Lowering the induced drag
Increasing the aerofoil camber
Which factor can be changed by deploying flaps for landing? (1,00 P.)
The position of the center of gravity
The effectiveness of the ailerons
The twist effect of the engine
The trim condition
The trim condition
What is the principle of a Fowler flap?
A profile-like flap is extended from the trailing edge of the wing
A flap from the rear bottom side of the wing is folded down
At high angles of attack a part of the leading edge lifts
The rear part of the wing is folded down
A profile-like flap is extended from the trailing edge of the wing
Fowler (highest CLmax and lowest drag)
> Slotted
> Split
> Plain (used in light aircraft)
A take-off with flaps in take-off position causes…
an increased rate of climb.
an increased acceleration.
a shortening of the take-off run.
a decrease in drag.
a shortening of the take-off run
Provided that no other procedure is described in the Aircraft Operating Handbook, after increasing the engine power in a go-around, the flaps may…
not be operated up to the minimum safe altitude.
be retracted to a middle position.
be fully retracted without any delay.
remain fully extended until reaching the traffic pattern.
be retracted to a middle position
How do lift and drag change when setting flaps to a lower position?
Lift increases, drag decreases
Lift increases, drag increases
Lift decreases, drag decreases
Lift decreases, drag increases
Lift increases, drag increases
The laminar boundary layer on the aerofoil is located between...
the transition point and the separation point.
the stagnation point and the transition point.
the transition point and the center of pressure.
the stagnation point and the center of pressure.
the stagnation point and the transition point.
**How does a laminar boundary layer differ from a turbulent boundary layer? **
The laminar boundary layer produces lift, the turbulent boundary layer produces drag
The turbulent boundary layer is thicker and provides less skin-friction drag
The laminar boundary layer is thinner and provides more skin-friction drag
The turbulent boundary layer can follow the airfoil camber at higher angles of attack
The turbulent boundary layer can follow the airfoil camber at higher angles of attack
SEPARATION POINT:
= Airflow stops following the curvature of the wing and starts moving freely
-At low AoA –> Separation point is located near the trailing edge
-As AoA increases –> Separation point moves forward
Vs
BOUNDARY LAYER:
= Layer where airflow velocity changes from zero at the aerofoil’s surface to the value o undisturbed airflow
-Boundary layer thickness = From surface to 99% velocity of undisturbed airflow (increases w/ distance from leading edge)
-Transition point = Laminar boundary layer turns into turbulent boundary layer
-LAMINAR boundary layer –> Thinner; less energy; less friction drag; more susceptible to flow separation
-TURBULENT boundary layer –> Thicker; more energy; more friction drag; less susceptible to flow separation
What structural item provides lateral stability to an airplane?
Differential aileron deflection
Wing dihedral
Vertical tail
Elevator
Wing dihedral
Which statement describes a situation of static stability?
An aircraft distorted by external impact will tend to an even more deflected position
An aircraft distorted by external impact will return to the original position
An aircraft distorted by external impact can return to its original position by rudder input
An aircraft distorted by external impact will maintain the deflected position
An aircraft distorted by external impact will return to the original position
“Longitudinal stability” is referred to as stability around which axis?
Propeller axis
Vertical axis
Longitudinal axis
Lateral axis
Lateral axis
Stability around which axis is mainly influenced by the center of gravity’s longitudinal position?
Vertical axis
Longitudinal axis
Gravity axis
Lateral axis
Lateral axis
What structural item provides directional stability to an airplane?
Differential aileron deflection
Large vertical tail
Wing dihedral
Large elevator
Large vertical tail
Rudder
Rotation around the vertical axis is called…
rolling.
pitching.
yawing.
slipping.
yawing
Rotation around the lateral axis is called…
rolling.
stalling.
yawing.
pitching.
pitching
The critical angle of attack…
increases with a front centre of gravity.
decreases with a rear centre of gravity.
is changed by different aircraft weights.
is not changed by different aircraft weights.
is NOT changed by different aircraft weights
In straight and level flight with constant performance of the engine, the angle of attack at the wing is…
greater than in a climb.
greater than at take-off.
smaller than in a descent.
smaller than in a climb.
smaller than in a climb
**What is the function of the horizontal tail (among other things)? **
To stabilise the aeroplane around the lateral axis
To initiate a curve around the vertical axis
To stabilise the aeroplane around the longitudinal axis
To stabilise the aeroplane around the vertical axis
To stabilise the aeroplane around the lateral axis
Pitch control
The elevator deflection during take-off rotation…
is increased for a front centre of gravity.
is increased for a rear centre of gravity.
is increased at high speeds.
is independent of the speed.
is increased for a front centre of gravity
The elevator moves an aeroplane around the…
lateral axis.
elevator axis.
longitudinal axis.
vertical axis.
lateral axis
What has to be considered with regard to the center of gravity position?
The center of gravity’s position can only be determined during flight.
Only correct loading can assure a correct and safe center of gravity position.
By moving the elevator trim tab, the center of gravity can be shifted into a correct position.
By moving the aileron trim tab, the center of gravity can be shifted into a correct position.
Only correct loading can assure a correct and safe center of gravity position.
Rudder deflections result in a turn of the aeroplane around the…
rudder axis.
lateral axis.
vertical axis.
longitudinal axis.
vertical axis
Deflecting the rudder to the left causes…
pitching of the aircraft to the right.
yawing of the aircraft to the right.
yawing of the aircraft to the left.
pitching of the aircraft to the left.
yawing of the aircraft to the left
What is the advantage of differential aileron movement?
The ratio of the drag coefficient to lift coefficient is increased
The adverse yaw is higher
The drag of the downwards deflected aileron is lowered and the adverse yaw is smaller
The total lift remains constant during aileron deflection
The drag of the downwards deflected aileron is lowered and the adverse yaw is smaller
**Which design feature can compensate for adverse yaw? **
Wing dihedral
Full deflection of the aileron
Aileron trim
Differential aileron defletion
Differential aileron defletion
Differential aileron deflection is used to…
keep the adverse yaw low.
avoid a stall at low angles of attack.
increase the rate of descent.
reduce wake turbulence.
keep the adverse yaw low
**The right aileron deflects upwards, the left downwards. How does the aircraft react?
**
Rolling to the left, no yawing
Rolling to the right, yawing to the right
Rolling to the right, yawing to the left
Rolling to the left, yawing to the right
Rolling to the right, yawing to the left
The aerodynamic rudder balance…
improves the rudder effectiveness.
reduces the control surfaces.
reduces the control stick forces.
delays the stall.
reduces the control stick forces
Which constructive feature has the purpose to reduce stearing forces?
T-tail
Vortex generators
Differential aileron deflection
Aerodynamic rudder balance
Aerodynamic rudder balance
What is the function of the static rudder balance?
To trim the controls almost without any force
To increase the control stick forces
To limit the control stick forces
To prevent control surface flutter
To prevent control surface flutter
During cruise flight with constant power setting, an aircraft shows a permanent tendency to raise the nose. How can this tendency be eliminated?
By deflecting the elevator trim tab upwards
By shifting the center of gravity backwards
By elevator deflection upwards
By deflecting the elevator trim tab downwards
By deflecting the elevator trim tab upwards
The trim tab at the elevator is defelected upwards.
In which position is the corresponding indicator?
Neutral position
Nose-up position
Nose-down position
Laterally trimmed
Nose-down position
What describes “wing loading”?
Drag per wing area
Drag per weight
Wing area per weight
Weight per wing area
Weight per wing area
Through which factor listed below does the load factor increase during cruise flight?
A forward centre of gravity
Higher aeroplane weight
An upward gust
Lower air density
An upward gust
Which statement regarding the “constant-speed propeller” is correct?
The propeller keeps the airspeed constant
The pitch of the propeller rises with higher speeds
The RPM decreases with lower speeds
The set RPM is kept constant by the motor power (MAP)
The pitch of the propeller rises with higher speeds
To keep the RPM constant with higher speed the prop must increase AoA and increase torque
**The change in pitch at a propeller blade from the root to the tip ensures… **
that the most thrust is produced at the blade tip.
that the most thrust is produced at the blade root.
a nearly constant load by a constant effective angle of attack over the entire length of the blade.
the largest possible angle of attack at the blade tip.
a nearly constant load by a constant effective angle of attack over the entire length of the blade.
After an engine failure, the windmilling propeller…
generates neither thrust nor drag.
has a greater pitch in feathered position.
generates drag rather than thrust.
improves the properties of the glide.
generates drag rather than thrust.
During a descent at idle power with constant speed, the propeller lever is moved backwards. How do the propeller pitch and sink rate change?
Propeller pitch is increased, sink rate is increased
Propeller pitch is increased, sink rate is decreased
Propeller pitch is decreased, sink rate is increased
Propeller pitch is decreased, sink rate is decreased
Propeller pitch is increased, sink rate is decreased
The bank in a two-minute turn (rate one turn) depends on the…
weight.
wind.
load factor.
TAS.
TAS
In a co-ordinated turn, how is the relation between the load factor (n)
and the stall speed (Vs)?
n is smaller than 1, Vs is greater than in straight and level flight.
n is greater than 1, Vs is greater than in straight and level flight.
n is smaller than 1, Vs is smaller than in straight and level flight.
n is greater than 1, Vs is smaller than in straight and level flight.
n is greater than 1, Vs is greater than in straight and level flight.
How is the balance of forces affected during a turn?
Lift force must be increased to compensate for the sum of centrifugal and gravitational force
The net force results from superposition of gravity and centripetal forces
The horizontal component of the lift force during a turn is the centrifugal force
A lower lift force compensates for a lower net force as compared to level flight
Lift force must be increased to compensate for the sum of centrifugal and gravitational force
The pressure compensation between wind upper and lower surface results in …
laminar airflow by wing tip vortices.
profile drag by wing tip vortices.
induced drag by wing tip vortices.
lift by wing tip vortices.
induced drag by wing tip vortices
What is meant by “ground effect”?
Increase of lift and increase of induced drag close to the ground
Decrease of lift and increase of induced drag close to the ground
Decrease of lift and decrease of induced drag close to the ground
Increase of lift and decrease of induced drag close to the ground
Increase of lift and decrease of induced drag close to the ground
What is the diffeence between spin and spiral dive?
Spin: stall at outer wing, speed constant;
Spiral dive: airflow at both wings, speed increasing rapidly
Spin: stall at inner wing, speed constant;
Spiral dive: airflow at both wings, speed increasing rapidly
Spin: stall at outer wing, speed increasing rapidly;
Spiral dive: airflow at both wings, speed constant
Spin: stall at inner wing, speed increasing rapidly;
Spiral dive: airflow at both wings, speed constant
Spin: stall at inner wing, speed constant;
Spiral dive: airflow at both wings, speed increasing rapidly
