Subsonic Aerodynamics | PPL(A) Principles of Flight - EASA & UK CAA
Aerodynamic degradation
Section titled "Aerodynamic degradation"Icing can cause controllability problems due to which of the following reasons?
Which of the options is the most difficult to spot (identify) during a pre-flight check?
Rime ice usually builds up close to the __(1)__, while clear ice __(2)__.
What is the correct option concerning ice accretion?
What does icing cause during flight?
Ice formation may lead to:
Icing causes performance degradation due to which of the following factors?
Which of the following phenomena distorts the profile shape of an airfoil during the flight most?
Basics, laws and definitions
Section titled "Basics, laws and definitions"Based on Bernoulli's Theorem, if the flow velocity is increased then:
Which of the following is correct according to Newton's 2nd Law?
Based on Bernoulli's principal, select the correct option:
Which option is correct according to the Law of Continuity for incompressible flow?
What is the principal difference between IAS and TAS?
How is density usually denoted?
Based on Bernoulli's principal, which of the following is correct if the flow velocity is reduced?
What is 100 kg of fuel in pounds (lb)?
If climbing with a constant IAS, what will happen to the TAS?
How is the airspeed measured on aeroplanes?
The aeroplane's speed indicator shows 180 km/h IAS. What is that in knots (KIAS) rounded to the nearest whole number?
What is 120 lb (pounds) in kg (kilograms)?
According to the Law of Continuity for an incompressible flow, which option is correct?
Which of the following is correct according to Newton's 3rd Law?
What does Bernoulli's equation state?
You require a minimum of 200 kg of fuel for a cross-country flight. The fuel slip states that 442 pounds of fuel has been uplifted. The performance mass and balance limit the maximum fuel to 220 kg. May you take off?
The reported headwind is 20 kt. What is this in m/s roughly?
What does Newton's First Law state?
Approximately what is 37,000 ft in km?
If the pilot descends with a constant IAS, what happens to the TAS?
For a standard tapered wing:
What is the most significant influencing factor on lift and drag in 2D flow?
100 N of Force exerted on an object with 11.013 lb (pounds) of mass, what is the acceleration?
Evaluate the following statements about 2D and 3D flows: 1. A 2D flow is a flow in which the components of the flow remain in a plane, such as a flow around a wing profile having a finite span. 2. A 3D flow is a flow in which the components of the flow extrude in all three axes of space, such as a flow around a wing having an infinite span.
What is the SI unit for "density"?
The angle of attack is defined as:
How is the "chordline" best defined?
Refer to figure ppl-080-001. Which of the following wing planforms represents a tapered wing?
Taper ratio is most commonly expressed as:
When calculating the velocity from the dynamic pressure, which density is assumed by the basic airspeed indicators?
Evaluate the following statements about 2D and 3D flow? 1. A 2D flow is a flow in which the components of the flow remain in a plane, such as a flow around a wing profile having a finite span. 2. A 3D flow is a flow in which the components of the flow extrude in all three axes of space, such as a flow around a wing having a finite span.
How is a "streamline" defined?
How can the resultant force be calculated empirically?
What does the Law of Continuity state?
The aerodynamic forces are usually calculated by the following general formula: Cl: dimensionless coefficient, ρ: density, V: velocity, S: surface area, MAC: Mean Aerodynamic Chord
What is the "relative thickness" of an airfoil?
How is the "relative camber" defined?
Which of the following options defines aerodynamic drag most accurately?
Which of these phenomena is dynamic pressure a function of?
What is the "mean camber line" of a cambered wing profile section?
A runway 2,200 m long, What is its equivalent lenth in ft (feet) rounded down to the nearest whole number?
What is 1,500 feet (ft) in meters (m) approximately?
Evaluate the following statements about 2D and 3D airflow: 1. A 2D flow is a flow in which the components of the flow remain in a plane, such as a flow around a wing profile having an infinite span. 2. A 3D flow is a flow in which the components of the flow extrude in all three axes of space, such as a flow around a wing having an infinite span.
How can you calculate lift, if: 1. cL = 1 2. S = 20 m2 3. v = 10 m/s 4. Density is standard sea-level density
How can Lift be empirically calculated?
How can the resultant force be calculated empirically: (cR: dimensionless coefficient, ρ: density, v: velocity, S: surface area, MAC: Mean Aerodynamic)
What is the aspect ratio of a wing having surface area of 20 m2 and a wingspan of 10 m?
Evaluate the following statements about 2D and 3D flows? 1. A 2D flow is a flow in which the components of the flow remain in a plane, such as a flow around a wing profile having an infinite span. 2. A 3D flow is a flow in which the components of the flow extrude in all three axes of space, such as a flow around a wing having a finite span.
The angle of attack (AoA) is the angle between the:
In aerodynamics, what is the resultant force?
What are aerodynamic forces a function of?
Where can total pressure be measured?
What is the aerodynamic lift?
For incompressible flow in a "venturi", which of the following is true?
What is the maximum camber of an airfoil?
What is 2200 NM in kilometers (km)?
Refer to figure ppl-080-001. Which of the following wing planforms represents a swept-back wing?
Define "Aspect ratio" (AR):
How can drag be empirically computed?
Consider the 'Aspect Ratio' (AR), what is its unit?
Refer to figure ppl-080-001. Which of the following wing planforms represents a rectangular wing?
For a rectangular wing, aspect ratio (AR) can be expressed as:
What does the term "incompressible" mean?
What is the ISA value for air density at sea level?
cLmax augmentation
Section titled "cLmax augmentation"How can trailing edge devices reduce the stall speed?
Lowering a trailing edge device __(1)__ the maximum lift coefficient, and hence __(2)__ the stall speed.
To fly the same airspeed with flaps deflected, compared to a clean configuration in straight & level, steady flight:
Fowler-type flaps increases the surface area and the maximum lift coefficient of the wing. How does it affect the stall speed (assuming all other factors constant)?
Fowler-type flaps increase the surface area and the maximum lift coefficient of the wing. If you lower them and start a manoeuver at the same time, increasing the load factor. How does it affect your stall speed (all other factors constant)?
What is the most effective type of trailing edge device listed below?
Flap jam may cause __(1)__, resulting in __(2)__ moments which may be difficult to balance out.
Deploying/deflecting the trailing edge devices effectively: __(1)__ stall speed, and __(2)__ landing distance.
A plain flap increases the maximum lift coefficient of the wing. How does it affect your stall speed (all other factors constant)?
What do slats as opposed to trailing edge devices create?
In general, the more a trailing edge flap is deflected, the more it __(1)__ the maximum lift coefficient, therefore the more it __(2)__ the stall speed.
When is the appropriate flap deflection beneficial/advantaeous?
Generally, the more a trailing edge flap is deflected, the more it __(1)__ the maximum lift coefficient and the more it __(2)__ the drag coefficient.
Coefficients
Section titled "Coefficients"The cL-alpha graph is considered to be: __(1)__ until, __(2)__.
Refer to figure ppl-080-002. Which of the following represents a cL-alpha curve for a symmetric airfoil profile?
How does the center of pressure of a symmetric airfoil move with an increase in angle of attack?
How does lift depend on the lift coefficient?
How does the center of pressure of a cambered airfoil move with decreasing AoA (angle of attack)?
A symmetrical airfoil profile produces: __(1)__ lift at __(2)__ degrees of angle of attack.
Which of the following options best describes the pressure distribution about a symmetrical airfoil at +4 degrees AoA (angle of attack)?
What is the definition of the center of pressure?
What is "induced drag" caused by?
Which of the following options lists the variables needed to calculate drag?
How does the CP (center of pressure) of a symmetric airfoil move with a decreasing AoA (angle of attack)?
Which of the following options best describes pressure distribution around a positively cambered airfoil, at an angle of attack (AoA) corresponding to the "zero lift angle of attack"?
Refer to figure ppl-080-002. Which of the following figures represents a cL-alpha curve for a positively cambered airfoil profile?
Which of the following options best describes the pressure distribution around a symmetrical airfoil at -4deg AoA (angle of attack)?
The parasite drag of an aeroplane is 1800 N. If we double the airspeed with all other factors being constant, how much will it be?
What is the dimension of the lift coefficient?
Which of the following options lists the variables needed to calculate lift?
A negatively-cambered airfoil produces: __(1)__ lift at __(2)__ degrees of angle of attack.
Increasing the AoA (angle of attack) of a cambered airfoil profile below the critical angle of attack: The center of pressure __(1)__, and the transition point __(2)__.
Refer to figure ppl-080-002. Which of the following figures represents the cL-alpha curve for a negatively cambered airfoil profile?
What does the induced drag coefficient equal?
The parasite drag of an aeroplane is 1800 N. How much will it be if we double the surface area, (assuming all other factors constant)?
At which point does strong separation of the airflow typically occur over the airfoil?
0 deg AoA (angle of attack) causes: __(1)__ lift for __(2)__ airfoil.
Which option best describes the effects of strong separation on an airfoil's performance
What is the correct version of the lift formula from the options below? (cL: lift coefficient, ρ: density, V: velocity, S: surface area)
Total drag of the wing is the sum of which of the following options?
How does the parasite drag change with speed?
An advantage of retractable landing gear (when retracted), reduces what?
Parasite drag is the sum of which of which of the following components?
The total drag of the wing is the sum of which of the following forces?
How is the induced drag affected by the speed of the aircraft?
What happens to the parasite drag if we double the airspeed?
What shape does the induced drag versus velocity curve have?
What shape does the parasite drag vs speed curve have?
If we double the airspeed, what happens to the induced drag?
Where is the minimum value of total drag achieved?
Ground effect
Section titled "Ground effect"When entering ground effect:
When leaving the 'ground effect', what happens to the induced angle of attack and induced drag?
What does airborne acceleration in ground effect assist with?
What does the 'ground effect' have on aircraft on performance:
When entering ground effect, what happens to the downwash of the wing?
When does the pilot take ground effect into practical consideration?
The stall
Section titled "The stall"What is the load factor in a steady, coordinated turn, using a bank angle of 60 deg?
Where does the stall occur along the wingspan of a twisted, strongly tapered-planform wing:
What does a forward center of gravity have on the stall speed?
Increasing altitude: __(1)__ stall speed in TAS, and __(2)__ stall speed in IAS.
You are flying in cloud/mist, at -5 deg C, with pitot-heat and carb heat on. You experience strong aerodynamic buffet and cannot maintain altitude at 65 kt, whereas your stall speed in straight and level flight is 58 kt. There is no aural or visual stall warning. What are your actions?
When the critical angle of attack is exceeded for a rectangular wing, what happens to the center of pressure?:
Flying close to your stall speed, you abruptly deflect the ailerons, as if you want to make a right turn (left aileron down, right aileron up), what is likely to happen?
Which of the following boundary layer types is more resistant to separation?
How does a stall warning device usually work on SEP/MEP (piston) aeroplanes?
With all other factors constant, how does the stall speed change, if the mass of the aeroplane is increased?
What happens to the boundary layer on the wing when exceeding the critical angle of attack?`
When flying close to the stall speed, what may an asymmetric upward gust lead to?
If an aeroplane is not fitted with any kind stall warning device, then:
Which statement is correct regarding a climbing turn?
You are in a high-bank angle turn, and suddenly the buffet onset and stall warning sounds. What are the appropriate actions?
How does stall speed change if mass of the aeroplane is reduced (assuming all other factors constant)?
The power idle stall speed is ...... as/than the power on stall speed.
Where does the stall initiate along the wingspan of an untwisted, swept-back wing?
You have accidentally entered into a spin. What are your recovery actions?
Strong (Notable) airflow separation is: __(1)__, and might lead to __(2)__.
Why is a spin is a very dangerous phenomenon?
What happens when the angle of attack (AoA) nears the critical angle of attack?
Where does the stall initiate along the wingspan of an untwisted, rectangular-planform wing?
What is correct regarding a descending steep turn?
How is the stall warning indicator tested to see if it is functional?
What happens to a rectangular wing planform, when the critical angle is exceeded:
where does the stall initiate along the wingspan of an untwisted, rectangular-planform wing with the ailerons deflected?
What lists the key indicators of aerodynamic separation during flight?
What is the term 'stall'?
Heavy rain can cause which of the following problems?
You always fly your aircraft with a half tank of fuel. On another day, with exactly the same conditions (density altitude etc.), except you need to fly full tanks to have enough fuel for a long cross-country flight. After take-off, you climb with the same airspeed as usual, but you experience a buffet. What can the cause be?
Which of the following options list the signs of the stall (impending stall)?
Along the wingspan of an untwisted and strongly tapered-planform wing, what stall characteristics does it have?
The stall speed for your aircraft is 55kt at sea level, you read 65kt from your airspeed indicator at 5000ft. Are you in a stall provided that all other factors remain unchanged?
Which option is correct regarding a climbing power-on stall?
The stall speed of an aeroplane is 60 kt in steady, straight and level flight, in the clean configuration. What will it be approximately in a 60 deg bank coordinated turn?
The friction drag created by a laminar boundary layer is:
Which of the following boundary layer types separates more easily?
You realise that your stall warning sounds are accompanied by an aerodynamic buffet and an inability to maintain altitude. What should your actions be?
Which of the following statements is correct regarding T-tailed aeroplanes?
Where on the aircraft is it advantageous to have a turbulent boundary layer?
What is an incipient spin is caused by?
Three-dimensional airflow round a wing and a fuselage
Section titled "Three-dimensional airflow round a wing and a fuselage"Wing tip vortices cause __(1)__ and, thus __(2)__ effective angle of attack.
Among other factors, what does the magnitude of the wing tip vortex depend on?
Complete the sentence: If ......, then induced drag increases.
What generates the "induced angle of attack"?
Define the induced angle of attack:
Which of the following options describe the characteristics of a wing tip vortex life?
Which of the following statements about wake turbulence is correct?
You approach the runway right behind a large airliner. How will the wing tip vortices of this airliner rotate, with reference to your current position?
What influence does the aeroplane's mass have on the wing tip vortices?
How is the three-dimensional relative airflow quantified?
The strength of the wake turbulence, among other factors, depends on which of the following factors?
What happens to the streamlines if the wing is considered finite (finite wingspan) in contrast to the 2D flow pattern?
In 3D flow, what is the correct statement regarding the (geometric) angle of attack?
The heavier the preceding aeroplane:
What does the induced angle of attack cause?
Complete the following sentence: The lower the aeroplane velocity, the ......
What do wing tip vortices cause?
Two-dimensional airflow around an aerofoil
Section titled "Two-dimensional airflow around an aerofoil"What will an increment in the angle of attack (AoA) result in?
What does a greater distance between the streamlines (compared to the free-stream distance) about a body?
Which of the following options best describes the: Pressure distribution about a symmetrical airfoil at 0deg of angle of attack (AoA)?
How does the center of pressure (CP) of a cambered airfoil move with increasing angle of attack (AoA)?
What pressure acts on the stagnation point?
What can one determine from analysing streamlines?
What is a practical application of the "stagnation point"?
What does a closer distance between streamlines about a body indicate?
What does a closer distance between streamlines about a body mean?
How can the pilot decrease the angle of attack (AoA)?
How would you define the "stagnation point"?
How can the pilot increase the angle of attack (AoA)?
How does increasing the angle of attack (AoA) influence lift?
A positively-cambered airfoil produces __(1)__ lift, at __(2)__ degrees angle of attack (AoA).