SPL - Principles of Flight

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About these flashcards

This flashcard set delves into the principles of flight at a university level, focusing on key concepts like drag, lift, and the dynamics of wing design. It explores how factors such as speed, angle of attack, and stability influence flight performance, with a particular emphasis on understanding the forces acting on an aircraft. Pilots, engineers, and aviation enthusiasts will find this set invaluable for grasping the fundamental physics behind flight mechanics and improving their practical flying skills.

Flashcards

Students

Language

English

Category

Technology

Level

University

Created / Updated

01.02.2025 / 04.05.2025

Similar cards

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

Lower density

Higher load factor

Decreasing weight

Lower altitude

Lower density

Higher load factor

Decreasing weight

Lower altitude

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

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

Turbulent layer at the leading wing areas, laminar boundary layer at the trailing areas

Turbulent boundary layer along the complete upper surface with separated airflow

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

Turbulent layer at the leading wing areas, laminar boundary layer at the trailing areas

Turbulent boundary layer along the complete upper surface with separated airflow

What structural item provides lateral stability to an airplane?

Differential aileron deflection

Elevator

Vertical tail

Wing dihedral

Differential aileron deflection

Elevator

Vertical tail

Wing dihedral

Which constructive feature is shown in the figure? See figure (PFA-006) L: Lift

Lateral stability by wing dihedral

Differential aileron deflection

Longitudinal stability by wing dihedral

Directional stability by lift generation

Lateral stability by wing dihedral

Differential aileron deflection

Longitudinal stability by wing dihedral

Directional stability by lift generation

"Longitudinal stability" is referred to as stability around which axis?

Vertical axis

Lateral axis

Longitudinal axis

Propeller axis

Vertical axis

Lateral axis

Longitudinal axis

Propeller axis

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

Gravity axis

Vertical axis

Longitudinal axis

Lateral axis

Gravity axis

Vertical axis

Longitudinal axis

Lateral axis

Rotation around the vertical axis is called...

yawing.

rolling.

slipping.

pitching.

yawing.

rolling.

slipping.

pitching.

The critical angle of attack...

decreases with a rear centre of gravity.

increases with a front centre of gravity.

is not changed by different aircraft weights.

is changed by different aircraft weights.

decreases with a rear centre of gravity.

increases with a front centre of gravity.

is not changed by different aircraft weights.

is changed by different aircraft weights.

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

To stabilise the aeroplane around the longitudinal axis

To initiate a curve around the vertical axis

To stabilise the aeroplane around the lateral axis

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

To stabilise the aeroplane around the vertical axis

Rudder deflections result in a turn of the aeroplane around the...

longitudinal axis.

rudder axis.

vertical axis.

lateral axis.

longitudinal axis.

rudder axis.

vertical axis.

lateral axis.

What is the advantage of differential aileron movement?

The drag of the downwards deflected aileron is lowered and the adverse yaw is smaller

The total lift remains constant during aileron deflection

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 ratio of the drag coefficient to lift coefficient is increased

The adverse yaw is higher

The aerodynamic rudder balance...

improves the rudder effectiveness.

reduces the control surfaces.

reduces the control stick forces.

delays the stall.

improves the rudder effectiveness.

reduces the control surfaces.

reduces the control stick forces.

delays the stall.

What describes "wing loading"?

Drag per weight

Drag per wing area

Wing area per weight

Weight per wing area

Drag per weight

Drag per wing area

Wing area per weight

Weight per wing area

Point number 1 in the figure indicates which flight state? See figure (PFA-008)

Best gliding angle

Inverted flight

Slow flight

Stall

Best gliding angle

Inverted flight

Slow flight

Stall

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

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

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

n is larger 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 lower than in straight and level flight.

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

n is larger 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.

During approach to the next updraft, the vertical speed indicator reads 3 m/s descent. Within the updraft you expect a mean rate of climb of 2 m/s. According to McCready, how should you adjust the speed during approach of the updraft?

The McCready ring should be set to 3 m/s, the recommended speed can be read at the McCready scale next to the expected rate of climb (2 m/s).

Outside of thermal cells, the McCready ring should be set to 0 m/s, the recommended speed can be read at the McCready scale next to the current rate of descent (3 m/s).

The McCready ring should be set to 2 m/s, the recommended speed can be read at the McCready scale next to the sum of current rate of descent at expected rate of climb (5 m/s).

The McCready ring should be set to 2 m/s, the recommended speed can be read at the McCready scale next to the current rate of descent (3 m/s).

The McCready ring should be set to 3 m/s, the recommended speed can be read at the McCready scale next to the expected rate of climb (2 m/s).

Outside of thermal cells, the McCready ring should be set to 0 m/s, the recommended speed can be read at the McCready scale next to the current rate of descent (3 m/s).

The McCready ring should be set to 2 m/s, the recommended speed can be read at the McCready scale next to the sum of current rate of descent at expected rate of climb (5 m/s).

The McCready ring should be set to 2 m/s, the recommended speed can be read at the McCready scale next to the current rate of descent (3 m/s).

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

Engine and propeller mounted fix on the fuselage.

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.

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

The glide ratio of a sailplane can be improved by which measures?

Cleaning, correct speed, retractable gear, taped gaps between wing and fuselage

higher airplane mass, thin airfoil, taped gaps between wing and fuselage

lower airplane mass, correct speed, retractable gear

forward C.G. position, correct speed, taped gaps between wing and fuselage

Cleaning, correct speed, retractable gear, taped gaps between wing and fuselage

higher airplane mass, thin airfoil, taped gaps between wing and fuselage

lower airplane mass, correct speed, retractable gear

forward C.G. position, correct speed, taped gaps between wing and fuselage

What effect is referred to as "adverse yaw"?

Aileron operation results in a yaw to the desired side due to less 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

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 desired side due to less 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

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

What is meant by "ground effect"?

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

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

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

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

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

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

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

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

The static pressure of gases work...

only in flow direction.

in all directions.

only in the direction of the total pressure.

only vertical to the flow direction.

Keyboard commands:

= turn,

= for-/backward,

= scroll

only in flow direction.

in all directions.

only in the direction of the total pressure.

only vertical to the flow direction.

Bernoulli's equation for frictionless, incompressible gases states that...

total pressure = dynamic pressure + static pressure.

dynamic pressure = total pressure + static pressure.

static pressure = total pressure + dynamic pressure.

total pressure = dynamic pressure - static pressure.

Keyboard commands:

= turn,

= for-/backward,

= scroll

total pressure = dynamic pressure + static pressure.

dynamic pressure = total pressure + static pressure.

static pressure = total pressure + dynamic pressure.

total pressure = dynamic pressure - static pressure.

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

lift without drag.

drag.

drag and lift.

constant drag at any speed.

Keyboard commands:

= turn,

= for-/backward,

= scroll

lift without drag.

drag.

drag and lift.

constant drag at any speed.

Number 2 in the drawing corresponds to the...

profile thickness.

chord.

angle of attack.

chord line.

Keyboard commands:

= turn,

= for-/backward,

= scroll

profile thickness.

chord.

angle of attack.

chord line.

The angle (alpha) shown in the figure is referred to as...

lift angle.

angle of incidence.

angle of attack.

angle of inclination.

Keyboard commands:

= turn,

= for-/backward,

= scroll

lift angle.

angle of incidence.

angle of attack.

angle of inclination.

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

aspect ratio.

trapezium shape.

wing sweep.

tapering.

Keyboard commands:

= turn,

= for-/backward,

= scroll

aspect ratio.

trapezium shape.

wing sweep.

tapering.

Which point on the aerofoil is represented by number 1?

Transition point

Stagnation point

Center of pressure

Separation point

Keyboard commands:

= turn,

= for-/backward,

= scroll

Transition point

Stagnation point

Center of pressure

Separation point

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

Low pressure is created above, higher pressure below the profile

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

Keyboard commands:

= turn,

= for-/backward,

= scroll

High pressure is created above, lower pressure below the profile

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

Low pressure is created above, higher pressure below the profile

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

The center of pressure is the theoretical point of origin of...

only the resulting total drag.

gravity forces of the profile.

all aerodynamic forces of the profile.

gravity and aerodynamic forces.

Keyboard commands:

= turn,

= for-/backward,

= scroll

only the resulting total drag.

gravity forces of the profile.

all aerodynamic forces of the profile.

gravity and aerodynamic forces.

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

Lift increases and drag decreases

Lift decreases and drag increases

Lift and drag decrease

Lift and drag increase

Keyboard commands:

= turn,

= for-/backward,

= scroll

Lift increases and drag decreases

Lift decreases and drag increases

Lift and drag decrease

Lift and drag increase

Pressure compensation on a wing occurs at the...

fuselage connections.

wing tips.

leading edge.

wing roots.

fuselage connections.

wing tips.

leading edge.

wing roots.

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

the lower part of the gear.

the front part of the fuselage.

the outer part of the ailerons.

the wing tips.

the lower part of the gear.

the front part of the fuselage.

the outer part of the ailerons.

the wing tips.

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

The induced drag will slightly decrease

The induced drag will increase

The induced drag will remain constant

The induced drag will collapse

The induced drag will slightly decrease

The induced drag will increase

The induced drag will remain constant

The induced drag will collapse

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 4

It increases by a factor of 2

It increases by a factor of 4

It decreases by a factor of 2

It decreases by a factor of 4

It increases by a factor of 2

It increases by a factor of 4

It decreases by a factor of 2

Which statement about induced drag during the horizontal cruise flight is correct?

Induced drag increases with increasing airspeed

Induced drag has a minimum at a certain speed and increases at higher as well as lower speeds

Induced drag decreases with increasing airspeed

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 has a minimum at a certain speed and increases at higher as well as lower speeds

Induced drag decreases with increasing airspeed

Induced drag has a maximum at a certain speed and decreases at higher as well as lower speeds

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

Form drag, skin-friction drag, interference drag

Induced drag, form drag, skin-friction drag

Interference drag and parasite drag

Induced drag and parasite drag

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

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.

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.

Engine and propeller mounted fix at the aircraft's nose

Pressure drag, interference drag and friction drag belong to the group of the...

main resistance.

total drag.

induced drag.

parasite drag.

main resistance.

total drag.

induced drag.

parasite 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