WorksheetsPOF 1
Total questions: 50
Worksheet time: 25mins
Density:
reduces as altitude increases
is unaffected by temperature change
increases with altitude increase
reduces with temperature reduction
The presence of water vapor:
in air will increase its density
in the atmosphere will increase the power output of a piston engine
in the atmosphere will increase the amount of lift generated by an aircraft for a given true airspeed
in air will reduce its density
Atmospheric pressure:
acts only vertically downwards
is measured in Pascals per square inch
acts in all directions
increases with altitude
The air pressure that acts on anything immersed in it:
is also known as Dynamic Pressure
is also known as Static Pressure
is greater at altitude than at sea level
is also known as Total Pressure
What properties of the Earth's atmosphere most influence the performance of aircraft?
its carbon dioxide content, temperature, pressure and humidity
Its oxygen content, pressure, and water vapor content
Its water vapor content, temperature, pressure and density
Its nitrogen content, oxygen content, temperature and pressure
A piston engine aircraft flies in that layer of the atmosphere called:
The Stratosphere
The Troposphere
The Mesosphere
The Tropopause
The respective percentages of the four most abundant gases that make up the atmosphere are?
Nitrogen 78% Oxygen 21% Argon 0.95% Carbon Dioxide 0.05%
Oxygen 78% Nitrogen 21% Argon 0.95% Carbon Dioxide 0.05%
Nitrogen 78% Oxygen 21% Argon 0.95% Carbon Monoxide 0.05%
Oxygen 78% Nitrogen 21% Argon 0.95% Carbon Monoxide 0.05%
When considering the changes in density of the air with altitude, which of the following four options is correct?
The temperature increase with increasing altitude causes density to increase
The reduction in pressure with increasing altitude causes density to reduce
The temperature reduction with increasing altitude causes density to increase
The increase in pressure with increasing altitude causes density to reduce
Assuming that the pressure at sea level is ISA, but the temperature is 10°C higher than ISA, the density will be:
as per ISA
greater than ISA
less than ISA
unaffected
Which of the following options contains the main constituent gases of the Earth's atmosphere?
Hydrogen, Carbon Dioxide and Helium
Nitrogen, Oxygen and Water Vapor
Nitrogen, Argon and Carbon Dioxide
Helium, Nitrogen and Carbon Monoxide
Complete the following sentence to give the most correct statement. At constant air temperature and volume, if the pressure of the air increases:
its density will decrease
its density will be unaffected because the volume remains constant
its density will be unaffected because the temperature remains constant
its density will increase
What is the definition of Relative Humidity?
The amount of water vapor present in a mass of air, at any temperature, expressed as a percentage of the maximum amount of water vapor that the air could support at the ISA sea-level temperature
The amount of water vapor present in a mass of air relative to the density of air
The amount of water vapor present The amount of water vapor present in a mass of air expressed as a percentage of the maximum amount of water vapor that the air can support at the same temperature
The amount of water vapor present in a given volume of air expressed as a percentage of the total mass of the air
What will be the effect on air density of a reduction in air pressure while humidity and temperature remain constant?
The air density will decrease
The air density will increase
The air density will remain unchanged
The density of the air is independent of pressure at constant volume
What is the equivalent temperature in Celsius of 77° Fahrenheit?
45° Celsius
25° Celsius
60° Celsius
172° Celsius
. If, on a given day, the actual outside air temperature at 3 000 feet is 12°C, what is the approximate difference between the actual and ISA temperature?
1 0C
11 0C
7 0C
3 0C
Dynamic pressure equals:
total pressure plus static pressure
static pressure minus total pressure
total pressure divided by static pressure
total pressure minus static pressure
Relative airflow is __________ and __________ the movement of the aircraft.
perpendicular to opposite to
parallel to opposite to
perpendicular to in the same direction as
parallel to in the same direction as
In straight and level flight, the free stream airflow pressure compared to the pressure of the air flowing under the forward section of a wing is:
Equal
Higher
Lower
of equal pressure but travelling faster
The velocity of air flowing over the upper surface of the wing of typical training light-aircraft increases when compared to the velocity of the free airflow. Which of the options below best describes the pressure considerations of the air flowing over the wing:
its dynamic pressure will decrease and its static pressure increase
its dynamic pressure will remain constant and its static pressure will decrease
its dynamic pressure will increase and its static pressure decrease
its dynamic pressure will decrease and its static pressure remain constant
The air flow over the wing's upper surface in straight and level flight, when compared with the airflow that is unaffected by the wing, will have:
a higher velocity
a higher density
a reduced velocity
the same velocity
Which of the four answer options most correctly completes the sentence? Increasing speed also increases lift because
lift is directly proportional to velocity
lift is directly proportional to the square of the airspeed
the increased velocity of the relative wind overcomes the increased drag
increasing speed decreases drag
1-Air has mass 2- Air is not compressible 3- Air is able to flow or change its shape when subject to even small pressures 4- The viscosity of air is very high 5 -Moving air has kinetic energy The correct combination of true statements, from the above options, is:
1,2, 3 and 5
2, 3 and 4
1 and 4
1,3, and 5
A moving mass of air possesses kinetic energy. An object placed in the path of such a moving mass of air will be subject to:
static pressure and dynamic pressure
static pressure
dynamic pressure
dynamic pressure minus static pressure
The Principle of Continuity states that, in a Stream tube of decreasing cross- sectional area, the speed of a subsonic and incompressible airflow will:
remain the same
decrease
increase
always become sonic
The angle of attack of an aerofoil is defined as
the angle between the chord line of the aerofoil and the horizon
the angle between the chord line of the aerofoil and the relative airflow
the angle between the chord line of the aerofoil and the aircraft's longitudinal axis
the angle between the mean camber line of the aerofoil and the relative airflow
An aerofoil section is designed to produce lift resulting from a difference in the:
negative air pressure below and a vacuum above the surface
higher air pressure below the surface and lower air pressure above the surface
vacuum below the surface and greater air pressure above the surface
higher air pressure at the leading edge than at the trailing edge
Which of the sentences below makes the most correct statement about lift?
Lift acts perpendicularly to the wing chord line
Lift acts parallel to the wing chord line
Lift acts perpendicularly to the wing mean camber line
Lift acts perpendicularly to the relative airflow
On aerofoil section, the force of lift acts perpendicular to and the force of drag acts parallel to the:
relative airflow
longitudinal axis
chord line
aerofoil section upper surface
A positively cambered aerofoil starts to produce lift at an angle of attack of approximately:
4 to 6 degrees
0 degrees
minus 4 degrees
16 degrees
If the Angle of Attack and other factors remain constant, and the airspeed is doubled, lift will be:
Doubled
one quarter of what it was
the same
quadrupled
Which of the answer options most correctly completes the sentence? The amount of lift a wing produces is directly proportional to:
the dynamic pressure minus the static pressure
the square root of the velocity of the air flowing over it
the air density
the air temperature
The centre of pressure is:
the force opposing gravity
the point through which the aircraft weight acts
the point through which total lift acts
the central point of the engine oil system
The total lift force is considered to act through which location in an aircraft's wing?
The wing's upper surface
Always forward of the Centre of Gravity (C of G)
The wing's C of G
The Centre of Pressure
Static pressure acts:
parallel to airflow
parallel to dynamic pressure
in all directions
downwards
Which of the following statements is correct?
Lift acts perpendicular to the horizontal and drag parallel in a rearwards direction
Drag acts parallel to the chord and opposite to the direction of motion of the aircraft and lift acts perpendicular to the chord
Lift acts at right angles to the top surface of the wing and drag acts at right angles to lift
Drag acts parallel to the relative airflow, opposing the motion of the aircraft, and Lift acts perpendicularly to the relative airflow
In which of the conditions described below will the Coefficient of Lift of a wing be at its maximum?
At the aircraft's maximum rate of climb speed
At or just before the stall
In level flight at an angle of attack of between 4° and 6°
At the aircraft's maximum angle of climb speed
The formula for lift is:
L = W
L = 1 /2 pV (CL) 2 S
L = CL 1 /2pV2 S
L = CL 1 /2p 2V S
Which of the following statements best accounts for how a lift force can be generated by a wing of aerofoil cross section whose upper surface is positively cambered and whose undersurface is uncambered?
The air flowing over the upper surface has a longer distance to travel than the air flowing under the wing
An upwards-acting reaction force is generated by the wing as it turns the airflow around it in a downwards direction
There is an upwards acting reaction to the airflow which bounces off the under surface of the wing as the airflow strikes the undersurface at a positive angle of attack
Awing of the aerofoil section described will naturally produce positive lift at any angle of attack
Which of the following statements best accounts for how the airflow around a wing of standard aerofoil cross section contributes to the lift force produced by the wing?
Awing of standard aerofoil cross-section acts like an inverted venturi tube
Because the total energy in the air passing above the wing is greater than the total energy in the air flowing beneath the win
Lift is produced by the wing "skipping" over the airflow in the same way as a flat stone might skip over water
The downwards Turning of the airflow by the wing produces a rate of change of momentum in the airflow, the reaction to which is a force acting on the wing in an upwards direction
Total pressure sensed by a Pitot Tube comprises:
pitot pressure plus dynamic pressure
pitot pressure minus dynamic pressure
static pressure plus dynamic pressure
dynamic pressure minus static pressure
Two identical aircraft of the same weight fly at two different altitudes (in straight and level flight and the same angle of attack). Assuming that other factors remain constant, that the air is incompressible, and that ISA conditions prevail, how do the true air speeds of the two aircraft compare?
They are the same
The True Air Speed (TAS) of the higher aircraft will be the greater
The TAS of the lower aircraft will be the greater
Altitude has no effect on the True Air Speed required to support a given aircraft weight at constant angle of attack
In accordance with Bernoulli's Theorem, where PT = Total Pressure, PS = Static pressure and q = Dynamic pressure:
PT + PS = Q
PT = PS – Q
PT - PS = Q
PS + PT = Q
When (normally at high angles of attack) the Boundary Layer separates from the surface of an aerofoil (at the Separation Point), airflow characteristics aft of the Separation Point can best be described as:
unpredictable and haphazard, leading to an abrupt decrease in lift force
smooth and laminar, leading to an increase in lift
a turbulent Boundary Layer, leading to a slight reduction in lift
smooth and laminar, creating a favorable Pressure Gradient
The symbol for dynamic pressure is:
Q
P
R
D
As indicated Air Speed (IAS) is reduced, in order to maintain altitude, the pilot must:
increase the angle of attack to maintain the correct lift force
decrease the angle of attack to reduce the drag
deploy the speed brakes to increase drag
reduce the thrust
Dynamic Pressure may be expressed by the formula:
Q = 1 /2p V2
Q = p V2
Q = p V
Q = 2 p V
The smooth flow of air, where each molecule follows the path of the preceding molecule, is a definition of:
Wind
turbulent flow
free-stream flow
laminar flow
If the cross sectional area of an airflow is mechanically reduced:
the mass flow remains constant and the static pressure increases
the velocity of the airflow remains constant and the mass flow increases
the mass flow remains constant and the velocity of the airflow increases
the velocity of the airflow remains constant and the kinetic energy increases
Dynamic pressure is:
the pressure change caused by heating when a moving airflow is brought completely to rest
the pressure due to the mass of air pressing down on the air beneath
the amount by which the pressure rises at a point where a moving airflow is brought completely to rest
the total pressure at a point where a moving airflow is brought completely to rest
The dynamic pressure exerted by the air on an aircraft's frontal surface is equal to:
air density times speed squared
half the air density times the true airspeed squared
half the true airspeed times the air density squared
half the air density times the indicated airspeed squared
