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Principles of Flight (aka Aerodynamics) - ORGANIZED BY THEME

1. AERODYNAMIC FUNDAMENTALS & FORCES

1.1. Lift, Drag & Pressure Concepts

1.1.1 What is shown by a profile polar?

ratio between total lift and drag depending on angle of attack
ratio between minimum rate of descent and best glide
lift coefficient cA at different angles of attack
ratio of cA and cD at different angles of attack

1.1.2 When changing the airflow speed (TAS, true airspeed) by a factor of 2, the parasite drag will…

increase by a factor of 2.
increase by a factor of 4.
increase by a factor of approximately 1.4.
will increase to a constant, maximum value.

1.1.3 Pressure drag, interference drag and friction drag belong to the group of the…

main resistance.
parasite drag.
induced drag.
total drag.

1.1.4 What kind of drag is NOT part of the parasite drag?

Induced drag
Interference drag
Form drag
Skin-friction drag

1.1.5 If surrounded by airflow (v>0), any arbitrarily shaped body produces…

drag and lift.
constant drag at any speed.
drag.
lift without drag.

1.1.6 What pressure pattern can be observed at a lift-generating wing profile at positive angle of attack?

High pressure is created above, lower pressure below the profile
Pressure below remains unchanged, lower pressure is created above the profile
Pressure above remains unchanged, higher pressure is created below the profile
Low pressure is created above, higher pressure below the profile

1.1.7 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 decreases with increasing airspeed
Induced drag increases with increasing airspeed

1.1.8 How do induced drag and parasite drag change with increasing airspeed during a horizontal and stable cruise flight?

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

1.1.9 When increasing the airflow speed by a factor of 2 while keeping all other parameters constant, how does the parasite drag change approximately?

It increases by a factor of 2
It decreases by a factor of 4
It decreases by a factor of 2
It increases by a factor of 4

1.1.10 Which kinds of drag contribute to total drag?

Form drag, skin-friction drag, interference drag
Induced drag, form drag, skin-friction drag
Interference drag and parasite drag
Induced drag and parasite drag

1.1.11 The pressure compensation between wing 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.

1.1.12 Bernoulli’s equation for frictionless, incompressible gases states that…

total pressure = dynamic pressure - static pressure.
total pressure = dynamic pressure + static pressure.
dynamic pressure = total pressure + static pressure.
static pressure = total pressure + dynamic pressure.

1.1.13 When air flows through a pipe with changing cross sections, the static pressure changes. The total pressure…

increases proportionally.
reduces proportionally.
does not change
changes proportionally.

1.1.14 Which answer describes the term “aerodynamic force”?

Component of the lifting force in airflow direction
Sum of the vectors of lift and weight force
Sum of the vectors of lift and drag force
Difference of the vectors of lift and weight force

1.1.15 Which of the following options describes the pressure pattern at a lift-generating wing profile passed by airflow?

Pressure below remains unchanged, lower pressure is created above the profile
High pressure is created above, lower pressure below the profile
Low pressure is created above, higher pressure below the profile
Pressure above remains unchanged, higher pressure is created below the profile

1.1.16 How do lift and drag change with decreasing air density (all other parameters remaining constant)?

They do not change
Lift will increase, drag will decrease
Lift and drag will decrease
Lift will decrease, drag will increase

1.1.17 Lift depends on…

lift coefficient, speed, air temperature, projected airfoil area.
lift coefficient, square of the speed, air density, projected airfoil area
flight weight force, speed, air density, projected airfoil area.
flight weight force, engine power, air density, projected airfoil area.

1.1.18 The drag coefficient…

cannot be lower than a non-negative, minimal value
may range from zero to an infinite positive value.
increases with increasing airspeed.
is proportional to the lift coefficient.

1.1.19 Which of the following answers characterises a thick profile compared to a thin profile at the same speed? The thick profile generates…

more drag and less lift.
more drag and more lift
more drag and equal lift.
equal drag and more lift.

1.1.20 How does the drag of the aircraft change when the speed is doubled? It…

doubles.
remains the same.
quadruples
Triples

1.2. Angle of Attack & Profile Characteristics

1.2.1 The critical angle of attack…

increases with a front centre of gravity.
is changed by different aircraft weights.
is not changed by different aircraft weights.
decreases with a rear centre of gravity.

1.2.2 What pattern can be found at the stagnation point?

Streamlines are divided into airflow above and below the profile
The boundary layer starts separating on the upper surface of the profile
All aerodynamic forces can be considered as attacking at this single point
The laminar boundary layer changes into a turbulent boundary layer

1.2.3 Which statement about lift and angle of attack is correct?

Increasing the angle of attack results in less lift being generated by the aerofoil
Decreasing the angle of attack results in more drag being generated by the aerofoil
Too large angles of attack can lead to an exponential increase in lift
Increasing the angle of attack too far may result in a loss of lift and an airflow separation

1.2.4 When increasing the angle of attack at cruise speed, the center of pressure will…

be positioned at 25% mean aerodynamic chord.
move backward.
move forward.
show no change in position.

1.2.5 The position of the centre of pressure at a positively shaped profile…

moves to the leading 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.
is located at approximately 25% of the chord, measured from the leading edge.

1.2.6 The laminar boundary layer on the aerofoil is located between…

the transition point and the center of pressure.
the stagnation point and the transition point.
the transition point and the separation point.
the stagnation point and the center of pressure.

1.2.7 Which point on the aerofoil is represented by number 1? (See figure PFA-009)

Transition point
Center of pressure
Separation point
Stagnation point

1.2.8 Number 2 in the drawing corresponds to the… (See figure PFA-010)

chord.
profile thickness.
angle of attack.
chord line.

1.2.9 Considering a normal profile during cruise, a laminar boundary layer can be expected…

in the rear section of the profile behind the separation point.
in the rear section of the profile ahead of the separation point.
in the forward section of the profile.
in the frictionless section of the profile.

1.2.10 The angle (alpha) shown in the figure is referred to as… (See figure PFA-003)

angle of incidence.
lift angle.
angle of inclination.
angle of attack.

1.2.11 Which point on the aerofoil is represented by number 3? (See figure PFA-009)

Separation point
Transition point
Center of pressure
Stagnation point

1.2.12 Which statement about the airflow around an aerofoil is correct if the angle of attack decreases?

The stagnation point remains constant
The stagnation point moves down
The center of pressure moves aft
The center of pressure moves forward

1.2.13 Number 3 in the drawing corresponds to the… (See figure PFA-010)

camber line.
chord.
chord line.
thickness.

1.2.14 In which way does the position of the center of pressure move at a positively shaped profile with increasing angle of attack?

It moves to the wing tips
It moves forward until reaching the critical angle of attack
It moves forward first, then backward
It moves backward until reaching the critical angle of attack

1.2.15 The “angle of attack” is the angle between…

the aircraft’s longitudinal axis and the relative airflow.
the aircraft’s longitudinal axis and the chord line.
the chord line and the relative airflow
the chord line of the elevator and the chord line of the wing.

1.2.16 “Profile depth” is the distance between the…

leading edge and trailing edge of a profile
wing root and the wing tip.
profile’s lower and upper edge at the thickest point.
profile’s lower and upper edge at the thinnest point.

1.2.17 The position of the center of pressure at a positively shaped profile…

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 leading edge while the angle of attack becomes smaller
is located at approximately 25% of the chord, measured from the leading edge.

1.2.18 Which statement concerning the angle of attack is correct?

Increasing the angle of attack results in decreasing lift
The angle of attack cannot be negative
The angle of attack is constant throughout the flight
A too large angle of attack may result in a loss of lift

1.3. Stagnation Point & Boundary Layer

1.3.1 Pressure compensation on a wing occurs at the…

fuselage connections.
leading edge.
wing roots.
wing tips.

1.3.2 Pressure equalisation between lower and upper side of the wing can be reduced by…

retracting flaps.
higher airplane mass.
reducing speed.
winglets.

1.3.3 The ‘boundary layer’ of a body in an airflow can be described as:

a thin layer with flow speeds ranging from twice the free airflow speed body’s surface to free airflow speed at some distance
an area of compressed air near the leading edge of a wing.
a thin layer with flow speeds ranging from zero at the body’s surface to free airflow speed at some distance
a layer behind the separation point with undefined air flow speeds.

1.3.4 See figure (AGK-011). The angle indicated by arrow number 1 shows the propeller’s…

geometric wing twist.
aerodynamic wing twist.
angle of incidence.
angle of attack.

1.3.5 In motorplanes the stall warning is usually activated by a change of…

the transition point.
the stagnation point.
the center of pressure.
the center of gravity.

1.3.6 How does a laminar boundary layer differ from a turbulent boundary layer?

The laminar boundary layer is thinner and provides more skin-friction drag
The turbulent boundary layer is thicker and provides less skin-friction drag
The turbulent boundary layer can follow the airfoil camber at higher angles of attack
The laminar boundary layer produces lift, the turbulent boundary layer produces drag

1.3.7 What types of boundary layers can be found on an aerofoil?

Turbulent boundary layer along the complete upper surface with separated airflow
Turbulent layer at the leading wing areas, laminar boundary layer at the trailing areas
Laminar layer at the leading wing areas, turbulent boundary layer at the trailing areas
Laminar boundary layer along the complete upper surface with non-separated airflow

1.3.8 What occurs at the “transition point”?

The change from turbulent to laminar airflow
The change from laminar to turbulent airflow
The lateral tilting of the aircraft with stall
Reaching the maximum lift coefficient

1.3.9 Where does “separation” on the aerofoil set in and in which direction does it move with increasing angle of attack?

On the leading edge of the profile, movement in airflow direction
On the entire upper side of the profile at the same time
At the profile’s upper side at the trailing edge, movement opposite to the airflow direction
On the profile’s lower side behind the transition point, movement in airflow direction

1.3.10 The laminar layer on the aerofoil is located between…

the transition point and the separation point.
the stagnation point and the transition point
the stagnation point and the center of pressure.
the transition point and the center of pressure.

1.3.11 Which answer explains the term “boundary layer”?

The turbulences which arise with the combination of different assemblies of the aircraft
The layer in which the airflow speed increases from zero up to full speed of the airflow
The circulating part of the airfoil-fuselage flows
The air molecules which are subject to turbulence after the transition point

1.3.12 The laminar boundary layer is situated between…

transition point and trim edge.
transition point and separation point.
stagnation point and pressure point.
stagnation point and transition point

1.4. Center of Pressure & Forces

1.4.1 The center of pressure is the theoretical point of origin of…

all aerodynamic forces of the profile.
gravity and aerodynamic forces.
gravity forces of the profile.
only the resulting total drag.

1.4.2 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.

2. WING DESIGN & AERODYNAMIC DEVICES

2.1. Wing Shape & Configuration

2.1.1 What is the purpose of winglets?

Reduction of induced drag.
Increase gliding performance at high speed.
Increase of lift and turning manoeuvering capabilities.
To increase efficiency of aspect ratio.

2.1.2 What structural item provides lateral stability to an airplane?

Elevator
Differential aileron deflection
Vertical tail
Wing dihedral

2.1.3 Which parts of an aircraft mainly affect the generation of induced drag?

the outer part of the ailerons.
the front part of the fuselage.
the wing tips.
the lower part of the gear.

2.1.4 Which constructive feature is shown in the figure? (See figure PFA-006)

Differential aileron deflection
Directional stability by lift generation
Longitudinal stability by wing dihedral
Lateral stability by wing dihedral

2.1.5 Which option states a benefit of wing washout?

Structurally the wing is made more rigid against rotation
Greater hardness because the wing can withstand more torsion forces
With the washout the form drag reduces at high speeds
At high angles of attack the effectiveness of the aileron is retained as long as possible

2.1.6 What describes “wing loading”?

Drag per weight
Wing area per weight
Drag per wing area
Weight per wing area

2.1.7 The ratio of span and mean chord length is referred to as…

aspect ratio.
trapezium shape.
tapering.
wing sweep.

2.1.8 Which design feature can compensate for adverse yaw?

Differential aileron deflection
Wing dihedral
Aileron trim
Full deflection of the aileron

2.1.9 Which of the listed wing shapes has the lowest induced drag?

Double trapezoidal shape
Trapezoidal shape
Rectangular shape
Elliptical shape

2.1.10 Which wing shape has the highest induced drag?

Rectangular wing
Trapeze-shaped wing
Ellipsoidal wing
Triangular-shaped wing

2.1.11 When the rigging angle of incidence of a wing is smaller on the outer side than on the inner (on the root), that is called…

geometric twist
V-shape.
aerodynamic twist.
aerodynamic torsion.

2.1.12 Which option states a benefit of aerodynamic washout?

At high angles of attack the effectiveness of the aileron is retained as long as possible
Structurally the wing is made more rigid against rotation
Greater hardness because the wing can withstand more torsion forces
With the washout the form drag reduces at high speeds

2.1.13 Pressure compensation on an aerofoil occurs at the…

leading edge.
wing tips.
trailing edge
wing roots.

2.1.14 Which of the following options is likely to produce large induced drag?

Large aspect ratio
Tapered wings
Small aspect ratio
Low lift coefficients

2.1.15 Which answer defines the term “wing load”?

Maximum mass an aircraft can carry
Maximum take-off mass
Mass of the aircraft per wing surface area
Mass of the air which the aircraft displaces

2.2. Flaps & Leading Edge Devices

2.2.1 What is the principle of a Fowler flap?

The rear part of the wing is folded down
A profile-like flap is extended from the trailing edge of the wing
At high angles of attack a part of the leading edge lifts
A flap from the rear bottom side of the wing is folded down

2.2.2 With regard to flaps, which of the following options provides a lift-increasing effect?

Increasing the aerofoil camber
Decreasing the angle of attack
Decreasing the form drag
Lowering the induced drag

2.2.3 Compared to trailing edge flaps, leading edge devices like slots…

increase the camber and allow a lower angle of attack.
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.

2.2.4 A take-off with flaps in take-off position causes…

an increased acceleration.
an increased rate of climb.
a shortening of the take-off run.
a decrease in drag.

2.2.5 How do lift and drag change when setting flaps to a lower position?

Lift increases, drag increases
Lift increases, drag decreases
Lift decreases, drag increases
Lift decreases, drag decreases

2.2.6 What kind of landing aids may not be retracted suddenly near the ground?

Spoilers
Airbrakes
Flaps
Schempp-Hirth flaps

2.2.7 Which effect (among others) causes lift to increase when extending the landing flaps?

Reduction of the form drag
Enlargement of the profile camber
Reduction of the angle of attack
Reduction of the induced drag

2.2.8 How does extending the flaps to landing position affect the final approach (engine idle)?

Minimum speed is smaller, the glide path remains the same
Minimum speed is greater, the glide path remains the same
Minimum speed remains the same, the glide path is steeper
Minimum speed is smaller, the glide path is steeper

2.2.9 When taking off with the flaps extended (take-off position)…

the climb rate increases.
the rotation speed increases.
the take-off ground roll is shortened
the acceleration increases.

2.3. Aileron & Control Surface Design

2.3.1 What is the advantage of differential aileron movement?

The drag of the downwards deflected aileron is lowered and the adverse yaw is smaller
The adverse yaw is higher
The total lift remains constant during aileron deflection
The ratio of the drag coefficient to lift coefficient is increased

2.3.2 The right aileron deflects upwards, the left downwards. How does the aircraft react?

Rolling to the left, no yawing
Rolling to the left, yawing to the right
Rolling to the right, yawing to the left
Rolling to the right, yawing to the right

2.3.3 Differential aileron deflection is used to…

reduce wake turbulence.
avoid a stall at low angles of attack.
keep the adverse yaw low
increase the rate of descent.

3. DRAG TYPES & ANALYSIS

3.1. Induced Drag

3.1.1 What is the purpose of winglets?

Reduction of induced drag.
Increase gliding performance at high speed.
Increase of lift and turning manoeuvering capabilities.
To increase efficiency of aspect ratio.

3.1.2 Which parts of an aircraft mainly affect the generation of induced drag?

the outer part of the ailerons.
the front part of the fuselage.
the wing tips.
the lower part of the gear.

3.1.3 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 decreases with increasing airspeed
Induced drag increases with increasing airspeed

3.1.4 How do induced drag and parasite drag change with increasing airspeed during a horizontal and stable cruise flight?

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

3.1.5 Which kinds of drag contribute to total drag?

Form drag, skin-friction drag, interference drag
Induced drag, form drag, skin-friction drag
Interference drag and parasite drag
Induced drag and parasite drag

3.1.6 The pressure compensation between wing 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.

3.1.7 Which effect does a decreasing airspeed have on the induced drag during a horizontal and stable cruise flight?

The induced drag will remain constant
The induced drag will collapse
The induced drag will increase
The induced drag will slightly decrease

3.1.8 Which of the following options is likely to produce large induced drag?

Large aspect ratio
Tapered wings
Small aspect ratio
Low lift coefficients

3.1.9 Induced drag is generated…

at the outer part of the ailerons.
at the trailing edge of the wing
at the front part of the aisle.
at the lower part of the gear.

3.2. Parasite Drag & Skin Friction

3.2.1 Pressure drag, interference drag and friction drag belong to the group of the…

main resistance.
parasite drag.
induced drag.
total drag.

3.2.2 Friction drag will be increased for example by:

Interfering airflow from fuselage and wings
Dead insects and dirt at the leading edge
A smoother surface
Increased airflow between lower and upper wing

3.2.3 Where is interference drag generated?

At the ailerons
At the gear
Near the wing tips
At the wing root

3.2.4 Which body of the same cross-sectional area has the smallest drag with the same inflowing air speed?

Plain disc
Streamlined body
Hollow hemisphere
Sphere

4. STALL & SPIN AERODYNAMICS

4.1. Stall Conditions

4.1.1 Flying slow close to stall conditions, the left wing is lower than the right wing. How can the stall be prevented?

Aileron to the right, push slighty on the elevator, gain some speed, all rudders neutral
Rudder left, push slighty on the elevator, gain some speed, all rudders neutral
Aileron and rudder to the right, gain some speed, push slightly on the elevator, all rudders neutral
Push on the elevator, keep wings level with coordinated inputs on rudder and aileron

4.1.2 Which statement about lift and angle of attack is correct?

Increasing the angle of attack results in less lift being generated by the aerofoil
Decreasing the angle of attack results in more drag being generated by the aerofoil
Too large angles of attack can lead to an exponential increase in lift
Increasing the angle of attack too far may result in a loss of lift and an airflow separation

4.1.3 How should the pilot react to an engaged stall warning?

Pull the elevator, decrease power
Pull the elevator, increase power
Raise the nose to decrease airspeed
Push the elevator, increase power

4.1.4 During a stall, the lift…

increases and drag decreases.
increases and drag increases.
decreases and drag decreases.
decreases and drag increases.

4.1.5 How do lift and drag change when approaching a stall condition?

Lift increases and drag decreases
Lift decreases and drag increases
Lift and drag increase
Lift and drag decrease

4.1.6 What leads to a decreased stall speed Vs (IAS)?

Higher load factor
Decreasing weight
Lower altitude
Lower density

4.1.7 What has to be expected with ice accretion on wings?

Reduced friction drag
An increased stall speed
Improved slow flight capabilities
A decreased stall speed

4.1.8 What is indicated by “buffeting” noticable at elevator stick?

C.G. position too far ahead
too fast, turbulence bubbles hitting on aileron
too slow, wing airflow stalled
Glider plane very dirty

4.1.9 Which statement concerning the angle of attack is correct?

Increasing the angle of attack results in decreasing lift
The angle of attack cannot be negative
The angle of attack is constant throughout the flight
A too large angle of attack may result in a loss of lift

4.1.10 A strong decrease of lift can suddenly occur…

when getting close to the stall speed
when the flaps are extended.
when the engine power is reduced.
when the propeller is set to low RPM / large pitch.

4.1.11 The stall warning will be activated just before reaching which speed?

4.1.12 With increasing wing load, the minimum flight speed…

decreases.
increases
remains constant.
is dependent only on the flap position.

4.1.13 After increasing the angle of attack during flight with best gliding speed, initially…

lift and drag increase
lift and drag decrease.
lift decreases and drag increases.
lift increases and drag decreases.

4.2. Spin & Recovery

4.2.1 Which statement regarding a spin is correct?

During recovery the ailerons should be crossed
Only very old aeroplanes have a risk of spinning
During the spin the speed constantly increases
During recovery the ailerons should be kept neutral

4.2.2 Following a single-wing stall and pitch-down moment, how can a spin be prevented?

Deflect all rudders opposite to lower wing
Pulling the elevator to bring the plane back to normal attitude
Rudder opposite lower wing, releasing elevator to build up speed
Pushing the elevator to build up speed to re-attach airflow on wings

4.2.3 A gliding plane is about to pitch down due to stall. What rudder input can prevent nose-dive and spin?

Slightly pull the elevator, ailerons opposite to lower wing
Keep airplane in level flight using rudder pedals
Release elevator, rudder opposite to lower wing
Ailerons neutral, rudder strongly kicked to lower wing

4.2.4 What is the difference between spin and spiral dive?

Spin: stall at inner wing, speed constant; Spiral dive: airflow at both wings, speed increasing rapidly
Spin: stall at inner wing, speed increasing rapidly; Spiral dive: airflow at both wings, speed constant
Spin: stall at outer wing, speed increasing rapidly; Spiral dive: airflow at both wings, speed constant
Spin: stall at outer wing, speed constant; Spiral dive: airflow at both wings, speed increasing rapidly

4.2.5 How is the spin influenced when power is added during a left spin with a clockwise spinning engine?

It is enforced
It is not influenced at all
It is strongly decreased
It decreases minimally

4.2.6 The spin tendency of an aircraft is greater…

with a forward center of gravity position.
when trim is “nose-heavy”.
with an aft center of gravity position
when trim is “tail-heavy”.

5. STABILITY & CONTROL

5.1. Longitudinal Stability (Lateral Axis)

5.1.1 Why is it not allowed to launch with the C.G. positioned beyond the aft limit?

Because increased nose-down moment may not be compensated
Because maximum permissible speed will be reduced significantly
Because structural limits may be exceeded
Because elevator inputs may not be sufficient for controlling flight attitude

5.1.2 Stabilization around the lateral axis during cruise is achieved by the…

wing flaps.
vertical rudder.
airlerons.
horizontal stabilizer.

5.1.3 “Longitudinal stability” is referred to as stability around which axis?

Propeller axis
Lateral axis
Vertical axis
Longitudinal axis

5.1.4 Stability around which axis is mainly influenced by the center of gravity’s longitudinal position?

Gravity axis
Longitudinal axis
Vertical axis
Lateral axis

5.1.5 Considering longitudinal stability, which C.G. position is most dangerous with a normal gliding plane?

Position far back within permissible C.G. limits
Position too far aside permissible C.G. limits.
Position beyond the rear C.G. limit
Position beyond the front C.G. limit

5.1.6 What is the function of the horizontal tail (among other things)?

To stabilise the aeroplane around the vertical axis
To stabilise the aeroplane around the longitudinal axis
To initiate a curve around the vertical axis
To stabilise the aeroplane around the lateral axis

5.1.7 During a straight and steady climb, which force acts additionally, and in the same direction as the drag force, resulting in more power required for climb than for horizontal flight?

The vertical component of the weight force.
A component of the thrust along the rearward flightpath.
A component of the weight force along the rearward flight path.
A component of the lift force along the forward flightpath.

5.1.8 The elevator deflection during take-off rotation…

is increased at high speeds.
is independent of the speed.
is increased for a front centre of gravity.
is increased for a rear centre of gravity.

5.1.9 Stability around the lateral axis (longitudinal stability) is achieved by…

the effects and construction of the elevator unit
the use of a V-tail.
a variable rigging angle of incidence of the wing.
a swept back wing.

5.1.10 Which constructive feature provides longitudinal stability to an airplane in normal configuration (empennage at tail)?

Differential aileron deflection
Downforce at the elevator
Positive wing dihedral
Trim plate at the tailfin

5.1.11 What is the purpose of the horizontal stabiliser?

Commencing turns around the vertical axis
Stabilising the aircraft around the longitudinal axis
Stabilising the aircraft around the vertical axis
Stabilising the aircraft around the lateral axis

5.1.12 The elevator deflection for a specific maneuver…

is increased with a front centre of gravity
is increased at high speeds.
is increased with a rear centre of gravity.
is independent of the speed.

5.2. Lateral Stability

5.2.1 What structural item provides lateral stability to an airplane?

Elevator
Differential aileron deflection
Vertical tail
Wing dihedral

5.2.2 Which constructive feature is shown in the figure? (See figure PFA-006)

Differential aileron deflection
Directional stability by lift generation
Longitudinal stability by wing dihedral
Lateral stability by wing dihedral

5.2.3 Stability around which axis is strongly influenced by the center of gravity’s position?

Longitudinal axis
Vertical axis
Gravity axis
Lateral axis

5.3. Directional Stability (Vertical Axis)

5.3.1 What structural item provides directional stability to an airplane?

Large elevator
Wing dihedral
Differential aileron deflection
Large vertical tail

5.3.2 Stability of the vertical axis can be achieved…

by the vertical stabilizer only.
only by the rudder.
by the pendulum effect of the fuselage and wing dihedral.
by the vertical tail and the fuselage shape

5.3.3 Rotation around the vertical axis is called…

yawing
slipping.
rolling.
pitching.

5.3.4 The movement around the vertical axis of the aircraft is called…

rolling.
pitching.
yawing
slipping.

5.4. Static Stability

5.4.1 Which statement describes a situation of static stability?

An aircraft distorted by external impact will maintain the deflected position
An aircraft distorted by external impact will return to the original position
An aircraft distorted by external impact will tend to an even more deflected position
An aircraft distorted by external impact can return to its original position by rudder input

5.5. Control Surface Balance & Adverse Yaw

5.5.1 What is the advantage of differential aileron movement?

The drag of the downwards deflected aileron is lowered and the adverse yaw is smaller
The adverse yaw is higher
The total lift remains constant during aileron deflection
The ratio of the drag coefficient to lift coefficient is increased

5.5.2 The aerodynamic rudder balance…

improves the rudder effectiveness.
reduces the control stick forces.
reduces the control surfaces.
delays the stall.

5.5.3 Which design feature can compensate for adverse yaw?

Differential aileron deflection
Wing dihedral
Aileron trim
Full deflection of the aileron

5.5.4 What effect is referred to as “adverse yaw”?

Rudder operation results in a rolling moment to the opposite side due to more lift generated by the faster moving wing.
Aileron operation results in a yaw to the opposite side due to more drag at the down-deflected aileron
Aileron operation results in a yaw to the opposite side due to more drag at the up-deflected aileron
Aileron operation results in a yaw to the desired side due to less drag at the down-deflected aileron

5.5.5 Which constructive feature has the purpose to reduce steering forces?

T-tail
Differential aileron deflection
Aerodynamic rudder balance
Vortex generators

5.5.6 Which constructive feature has the purpose to reduce stearing forces?

Differential aileron deflection
Aerodynamic rudder balance
T-tail
Vortex generators

5.5.7 What is the function of the static rudder balance?

To prevent control surface flutter
To limit the control stick forces
To increase the control stick forces
To trim the controls almost without any force

5.5.8 The adverse-yaw effect can occur…

during steep turns with more than 45° bank angle.
with rudder deflection.
on the elevator at every speed range.
with aileron deflection during slow-flight conditions

5.5.9 Which answer describes the term “adverse yaw momentum”?

A yawing momentum in the same direction as the rolling momentum
A yawing momentum opposite to the direction of the rolling momentum
A rotation momentum around the longitudinal axis opposite to the aileron deflection
A rolling momentum additional to the rudder deflection

6. CENTER OF GRAVITY & LOADING

6.1. C.G. Position Effects

6.1.1 Why is it not allowed to launch with the C.G. positioned beyond the aft limit?

Because increased nose-down moment may not be compensated
Because maximum permissible speed will be reduced significantly
Because structural limits may be exceeded
Because elevator inputs may not be sufficient for controlling flight attitude

6.1.2 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.
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.

6.1.3 Stability around which axis is mainly influenced by the center of gravity’s longitudinal position?

Gravity axis
Longitudinal axis
Vertical axis
Lateral axis

6.1.4 Considering longitudinal stability, which C.G. position is most dangerous with a normal gliding plane?

Position far back within permissible C.G. limits
Position too far aside permissible C.G. limits.
Position beyond the rear C.G. limit
Position beyond the front C.G. limit

6.1.5 Trim masses or lead plates must be secured firmly when installed into a gliding plane, so that…

the glider pilot will not be hurt during flight in thermal turbulences.
the maximum allowed mass will not be exceeded.
they will not block rudders or induce any C.G. shift.
a comfortable seat position will be assured for the glider pilot.

6.1.6 The elevator deflection during take-off rotation…

is increased at high speeds.
is independent of the speed.
is increased for a front centre of gravity.
is increased for a rear centre of gravity.

6.1.7 The elevator deflection for a specific maneuver…

is increased with a front centre of gravity
is increased at high speeds.
is increased with a rear centre of gravity.
is independent of the speed.

6.1.8 The spin tendency of an aircraft is greater…

with a forward center of gravity position.
when trim is “nose-heavy”.
with an aft center of gravity position
when trim is “tail-heavy”.

6.2. Weight & Wing Loading

6.2.1 What leads to a decreased stall speed Vs (IAS)?

Higher load factor
Decreasing weight
Lower altitude
Lower density

6.2.2 What describes “wing loading”?

Drag per weight
Wing area per weight
Drag per wing area
Weight per wing area

6.2.3 With increasing wing load, the minimum flight speed…

decreases.
increases
remains constant.
is dependent only on the flap position.

6.2.4 Which answer defines the term “wing load”?

Maximum mass an aircraft can carry
Maximum take-off mass
Mass of the aircraft per wing surface area
Mass of the air which the aircraft displaces

7. PROPELLER & ENGINE SYSTEMS

7.1. Propeller Design & Function

7.1.1 What engine design at a Touring Motor Glider (TMG) results in least drag?

Engine and propeller mounted fix at the aircraft’s nose
Engine and propeller mounted stowable on the fuselage
Engine and propeller mounted fix at the horizontal stabilizer
Engine and propeller mounted fix on the fuselage.

7.1.2 The change in pitch at a propeller blade from the root to the tip ensures…

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.
that the most thrust is produced at the blade tip.
that the most thrust is produced at the blade root.

7.1.3 See figure (AGK-011). The angle indicated by arrow number 1 shows the propeller’s…

geometric wing twist.
aerodynamic wing twist.
angle of incidence.
angle of attack.

7.2. Engine & Propeller Operation

7.2.1 After an engine failure, the windmilling propeller…

improves the properties of the glide.
has a greater pitch in feathered position.
generates neither thrust nor drag.
generates drag rather than thrust.

7.2.2 What effects typically result from propeller icing?

Reduced power output, increasing RPM.
Reduced power output, decreasing RPM.
Increased power output, decreasing RPM.
Increased power output, increasing RPM.

7.2.3 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 decreased
Propeller pitch is decreased, sink rate is decreased
Propeller pitch is increased, sink rate is increased
Propeller pitch is decreased, sink rate is increased

7.2.4 Which statement regarding the “constant-speed propeller” is correct?

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
The propeller keeps the airspeed constant

8. FLIGHT CHARACTERISTICS & PERFORMANCE

8.1. Gliding Performance & Descent

8.1.1 In which mentioned situation is the total drag at its minimum?

Induced drag is smaller than parasite drag
Parasite drag is twice as much as induced drag
Induced drag is twice as much as parasite drag
Parasite drag is equal to induced drag

8.1.2 What is the effect in general when using a thicker airfoil compared to a thinner airfoil on stationary glide with the same airplane mass?

Steady speed with less lift
Higher speed with less lift
Less speed with more lift
Lower speed with steady lift

8.1.3 A sailplane is operated with additional water ballast. How do best gliding angle and speed of best glide change, when compared to flying without water ballast?

best gliding angle descreases, best glide speed decreases.
best gliding angle remains unchanged, best glide speed decreases.
best gliding angle remains increases, best glide speed increases.
best gliding angle remains unchanged, best glide speed increases.

8.2. Turning & Maneuvering

8.2.1 The bank in a two-minute turn (rate one turn) depends on the…

load factor.
wind.
TAS.
weight.

8.2.2 What can be said about the load factor (n) and the stall speed (Vs) in a co-ordinated turn?

n is lower than 1, Vs is higher than in straight and level flight.
n is lower than 1, Vs is lower than in straight and level flight.
n is larger than 1, Vs is higher than in straight and level flight.
n is larger than 1, Vs is lower than in straight and level flight.

8.2.3 How is the balance of forces affected during a turn?

The horizontal component of the lift force during a turn is the centrifugal force
The net force results from superposition of gravity and centripetal forces
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

8.2.4 Through which factor listed below does the load factor increase during cruise flight?

Lower air density
An upward gust
A forward centre of gravity
Higher aeroplane weight

8.2.5 How can a pilot maintain the altitude during a co-ordinated steep turn?

The rudder is operated into the opposite direction
The rudder is operated in the rotating direction
The elevator is pulled accordingly
The trim is set to nose-heavy

8.2.6 Through which factor listed below does the load factor decrease during cruise flight?

A downward gust
An aft centre of gravity
Higher air density
Lower aeroplane weight

8.3. Ground Effect

8.3.1 What is meant by “ground effect”?

Decrease of lift and decrease of induced drag close to the ground
Increase of lift and increase of induced drag close to the ground
Decrease of lift and increase of induced drag close to the ground
Increase of lift and decrease of induced drag close to the ground

8.4. Climb Flight

8.4.1 In straight and level flight with constant performance of the engine, the angle of attack at the wing is…

smaller than in a descent.
smaller than in a climb.
greater than in a climb.
greater than at take-off.

8.4.2 During a straight and steady climb, which force acts additionally, and in the same direction as the drag force, resulting in more power required for climb than for horizontal flight?

The vertical component of the weight force.
A component of the thrust along the rearward flightpath.
A component of the weight force along the rearward flight path.
A component of the lift force along the forward flightpath.

8.5. Level Flight Forces

8.5.1 With regard to the forces acting, how can stationary gliding be described?

The sum the air forces acts along with the lift force
The sum of air forces acts along the direction of air flow
The sum of air forces compensates the gravity force
The lift force compensates the drag force

8.5.2 Which force does NOT act during straight and level flight?

Lift force
Centrifugal force
Gravitational force
Drag force

9. TRIM & CONTROL INPUTS

9.1. Trim Tab Operation

9.1.1 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 deflecting the elevator trim tab downwards
By elevator deflection upwards

9.1.2 The trim tab at the elevator is deflected upwards. In which position is the corresponding indicator?

Laterally trimmed
Nose-down position
Neutral position
Nose-up position

9.1.3 What is a bendable trim tab?

A balance mass at a control surface
A term for a rudder balance
A trim device adjustable in flight
A fixed tab attached to the rudder or the aileron

9.1.4 The trim tab at the elevator is defelected upwards. In which position is the corresponding indicator?

Neutral position
Laterally trimmed
Nose-up position
Nose-down position

9.2. Control Surface Movement

9.2.1 The elevator moves an aeroplane around the…

longitudinal axis.
vertical axis.
elevator axis.
lateral axis.

9.2.2 The right aileron deflects upwards, the left downwards. How does the aircraft react?

Rolling to the left, no yawing
Rolling to the left, yawing to the right
Rolling to the right, yawing to the left
Rolling to the right, yawing to the right

9.2.3 Deflecting the rudder to the left causes…

pitching of the aircraft to the right.
pitching of the aircraft to the left.
yawing of the aircraft to the right.
yawing of the aircraft to the left.

9.2.4 Which control affects primarily the movement around the longitudinal axis?

Rudder
Aileron
Elevator
Trim

10. STRUCTURAL & SAFETY LIMITS

10.1. Flutter & Structural Issues

10.1.1 “Flutter” may occur in which speed range?

At too low airspeeds (< Vs0)
At too high airspeeds (> VNE)
Within the yellow arc on the airspeed indicator
At too low airspeeds (< Vs1)

10.1.2 As means to prevent flutter…

flaps should be retracted.
airspeed should should be increased at first indication of flutter.
the mass of the rudders should not be changed.
uneven areas on the area should be filled with paint or spattle.

10.1.3 The term ‘flutter’ refers to…

the separation of airflow at too high angles of attack.
vibration and oscillation of the ailerons at too low airspeeds.
a stabilizing effect when at speeds higher than VNE.
vibration and oscillation of the ailerons at too high airspeeds.

10.2. Airspeed Limits

10.2.1 The maximum permissible speed for an aircraft…

is compulsory for aerobatics.
cannot be achieved by a vertical nose down diving flight.
must never be exceeded
should only be exceeded in still air.

10.2.2 Which answer describes the “manoeuvring speed”?

Maximum speed with which abrupt, full control deflection
Maximum speed for steep turns
Minimum speed for steep turns
Initial speed for aerobatic figures

10.3. Icing Effects

10.3.1 What has to be expected with ice accretion on wings?

Reduced friction drag
An increased stall speed
Improved slow flight capabilities
A decreased stall speed

10.3.2 In icing conditions, at which point will the most ice arise on an aeroplane?

On the upper and lower side of the control surfaces
On the pitot tube and the static pressure ports
On the upper und lower side of the wing’s trailing edge
On all frontal areas of the airframe, the wings, and the tail

11. PROFILE & AIRFOIL CHARACTERISTICS

11.1. Profile Types & Features

11.1.1 Number 2 in the drawing corresponds to the… (See figure PFA-010)

chord.
profile thickness.
angle of attack.
chord line.

11.1.2 Number 3 in the drawing corresponds to the… (See figure PFA-010)

camber line.
chord.
chord line.
thickness.

11.1.3 “Profile depth” is the distance between the…

leading edge and trailing edge of a profile
wing root and the wing tip.
profile’s lower and upper edge at the thickest point.
profile’s lower and upper edge at the thinnest point.

11.1.4 The illustrated profile is a / an…

normal profile.
symmetrical profile
laminar profile.
S-profile.

11.1.5 A symmetrical profile…

does not produce lift.
has the least induced drag with a positive attack angle.
has a non-moving center of pressure
can only be flown upside-down.

11.2. Profile Twist & Washout

11.2.1 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…

arrow shape.
V-form.
aerodynamic washout.
geometric washout.

11.2.2 When the rigging angle of incidence of a wing is smaller on the outer side than on the inner (on the root), that is called…

geometric twist
V-shape.
aerodynamic twist.
aerodynamic torsion.

11.2.3 Which option states a benefit of aerodynamic washout?

At high angles of attack the effectiveness of the aileron is retained as long as possible
Structurally the wing is made more rigid against rotation
Greater hardness because the wing can withstand more torsion forces
With the washout the form drag reduces at high speeds

11.2.4 The “twist” of the aerofoil causes…

the airflow on the outer wing to stall sooner at high angles of attack and the induced drag to decrease.
the airflow on the inner wing to stall sooner at high angles of attack and the induced drag to decrease.
the airflow to stall later in the area of the aileron and the induced drag to increase
the airflow to stall sooner in the area of the aileron and the induced drag to decrease.

12. ADVANCED AERODYNAMIC CONCEPTS

12.1. Vortex Development

12.1.1 Wing tip vortex development begins during which phase of flight?

As soon as the aircraft starts moving
While setting take-off power during take-off run
When lift is being generated during rotation
While setting flaps to lower position

12.1.2 The start of vortex development is created during which phase of flight?

While setting take-off power during take-off run
While setting flaps to lower position
As soon as the aircraft starts moving
When lift is being generated during rotation

12.2. Aspect Ratio & Wing Geometry

12.2.1 The ratio of span and mean chord length is referred to as…

aspect ratio.
trapezium shape.
tapering.
wing sweep.

12.2.2 Which of the listed wing shapes has the lowest induced drag?

Double trapezoidal shape
Trapezoidal shape
Rectangular shape
Elliptical shape

12.2.3 Which wing shape has the highest induced drag?

Rectangular wing
Trapeze-shaped wing
Ellipsoidal wing
Triangular-shaped wing

12.2.4 Which of the following options is likely to produce large induced drag?

Large aspect ratio
Tapered wings
Small aspect ratio
Low lift coefficients

12.3. Static Pressure Behavior

12.3.1 The static pressure of gases works…

in all directions.
only vertical to the flow direction.
only in the direction of the total pressure.
only in flow direction.

12.3.2 The static pressure of gases work…

in all directions
only in flow direction.
only in the direction of the total pressure.
only vertical to the flow direction.

END OF LINE

Total Questions: 169 Organized into: 12 Main Themes with 31 Sub-Categories