Principles of Flight Flashcards
Compared to trailing edge flaps, leading edge devices like Slots… (1,00 P.)
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… (1,00 P.)
horizontal stabilizer.
airlerons.
wing flaps.
vertical rudder.
horizontal stabilizer.
Flying with speeds higher than the never-exceed-speed (vNE) may result in… (1,00 P.)
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? (1,00 P.)
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? (1,00 P.)
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… (1,00 P.)
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… (1,00 P.)
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.
If surrounded by airflow (v>0), any arbitrarily shaped body produces… (1,00 P.)
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… (1,00 P.)
center of gravity.
center of pressure.
lift point.
transition point.
center of pressure.
The center of pressure is the theoretical point of origin of… (1,00 P.)
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.
Number 2 in the drawing corresponds to the… See figure (PFA-010) (1,00 P.)
chord line.
chord.
angle of attack.profile
thickness.
https://cloud.wafa-sadri.de/s/Ns4pt7jRYLfTKQ6
chord
Number 3 in the drawing corresponds to the…
See figure (PFA-010) (1,00 P.)
chord.
thickness.
camber line.
chord line.
https://cloud.wafa-sadri.de/s/Ns4pt7jRYLfTKQ6
camber line.
The angle of attack is the angle between… (1,00 P.)
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… (1,00 P.)
trapezium shape.
tapering.
aspect ratio.
wing sweep.
aspect ratio.
Which point on the aerofoil is represented by number 3? See figure (PFA-009) (1,00 P.)
Separation point
Center of pressure
Stagnation point
Transition point
https://cloud.wafa-sadri.de/s/Ns4pt7jRYLfTKQ6
Transition point
Which point on the aerofoil is represented by number 3? See figure (PFA-009) (1,00 P.)
? Separation point
? Center of pressure
? Stagnation point
? Transition point
Which point on the aerofoil is represented by number 4?
See figure (PFA-009) (1,00 P.)
Center of pressure
Separation point
Transition point
Stagnation point
https://cloud.wafa-sadri.de/s/Ns4pt7jRYLfTKQ6
Separation point
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
Which point on the aerofoil is represented by number 1? See figure (PFA-009) (1,00 P.)
Transition point
Stagnation point
Center of pressure
Separation point
https://cloud.wafa-sadri.de/s/Ns4pt7jRYLfTKQ6
Stagnation point
What pattern can be found at the stagnation point? (1,00 P.)
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? (1,00 P.)
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… (1,00 P.)
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.
In which way does the position of the center of pressure move at a positively shaped profile with increasing angle of attack? (1,00 P.)
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? (1,00 P.)
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? (1,00 P.)
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? (1,00 P.)
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
The angle (alpha) shown in the figure is referred to as…
See figure (PFA-003)
DoF: direction of airflow (1,00 P.)
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… (1,00 P.)
aerodynamic washout.
arrow shape.
V-form.
geometric washout.
geometric washout.
Which option states a benefit of wing washout? (1,00 P.)
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? (1,00 P.)
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? (1,00 P.)
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… (1,00 P.)
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… (1,00 P.)
wing roots.
wing tips.
trailing edge.
leading edge.
wing tips.
Which of the following options is likely to produce large induced drag? (1,00 P.)
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? (1,00 P.)
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? (1,00 P.)
At the wing root
At the ailerons
At the the gear
Near the wing tips
At the wing root
Which curve represents the induced drag?
See Appendix (PFA-011) (1,00 P.)
1
4
2
3
1
Pressure drag, interference drag and friction drag belong to the group of the… (1,00 P.)
induced drag.
parasite drag.
main resistance.
total drag.
parasite drag.
What kind of drag is NOT part of the parasite drag? (1,00 P.)
Interference drag
Skin-friction drag
Induced drag
Form drag
Induced drag
How do induced drag and parasite drag change with increasing airspeed during a horizontal and stable cruise flight? (1,00 P.)
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
Which of the listed wing shapes has the lowest induced drag? (1,00 P.)
Elliptical shape
Double trapezoidal shape
Rectangular shape
Trapezoidal shape
Elliptical shape