COMMERCIAL PILOT LICENCE (CPL)
(AEROPLANE) AERODYNAMICS - CADA
AIRCRAFT MOTION
● Pitch about the lateral axis through elevators
○ Pitch down is nose down
○ Pitch up is nose up
● Roll about the longitudinal axis through ailerons
○ Roll left is left wing down
○ Roll right is right wing down
● Yaw about the normal/vertical axis through rudder
○ Yaw left is nose left
○ Yaw right is nose right
● All motion acts through the centre of gravity
AIRCRAFT COMPONENTS
● Spinner
● Propeller
● Engine owl
● Fuselage
● Landing gear or undercarriage
● Wing strut or lift strut
● Wing or mainplane
● Ailerons
● Flaps
● Horizontal stabiliser or tailplane
● Elevator
● Vertical stabiliser or fin and dorsal
● Rudder
,FORCE
● A push or pull attempting to change the state of motion of something
● Has magnitude, a point at which it is applied and a direction acting
● Represented with a vector
VECTOR
● Force represented as a line
RESULTANT
● A vector with the same overall effect as the combination of other
vectors
EQUILIBRIUM
● When speed or direction are not changing
PRESSURE
● Force acting over an area (i.e. force divided by area)
WING LOADING
● Aircraft weight divided by wing area
● A form of pressure
WORK
● Force multiplied by distance (i.e. small force over a large distance, or
large force over a small distance)
● Therefore, if drag is the force in question, it must be kept at a
minimum to produce the largest distance (i.e. range)
POWER
● The rate at which work is being done (i.e. work divided by time)
● Therefore, if you consider fuel flow as a measure of power, minimum
, ●
power means minimum fuel flow, and thus the longest time to
exhaustion (i.e. endurance)
● RPM is also a measure of power, therefore minimising RPM ensures
maximum endurance
● Power is proportional to speed to the power of 3
○ For example, to travel at twice the speed, 8 times the power is
required (2^3 = 8)
KINETIC ENERGY
● Energy, being the ability to do work, because of motion
● 1/2*m*v^2
STATIC PRESSURE
● Pressure applied to a surface from the motion of molecules in gas
● At sea level, in ISA conditions:
○ 14.7 psi
○ 29.92 inches of Mercury
○ 1013.25 hPA
● Measured by the static port on aircraft
DYNAMIC PRESSURE
● Additional pressure due to the kinetic energy of gas in movement
● Source of aerodynamic forces
● Measured by the airspeed indicator
TOTAL PRESSURE
● Static pressure plus dynamic pressure
● Measured by the pitot tube
PITOT TUBE
● Collects a sample of the oncoming airstream and guides it into a
dead-end capsule
, ● Measures total pressure
STATIC PORT
● Collects a sample of the airstream perpendicular to airflow and
guides it into the space surrounding the capsule
AIRSPEED INDICATOR
● Measures the pressure difference between the pitot tube and static
port to assume the dynamic pressure, which is proportional to
airspeed
● Output is known as indicated airspeed
● Subject to position and instrument error
POSITION ERROR
● Arises when the pitot tube is not directly parallel with airflow and/or
the static port reads incorrectly due to airspeed or attitude changes
in flight
INSTRUMENT ERROR
● Internal components of the airspeed indicator preventing the
instrument from providing an accurate reading
CALIBRATED AIRSPEED
● Indicated airspeed corrected for position and instrument error
● Also rectified airspeed
● Insignificant for most VFR GA aircraft
● Subject to density error
TRUE AIRSPEED
● Calibrated airspeed corrected for density error
DENSITY ERROR
(AEROPLANE) AERODYNAMICS - CADA
AIRCRAFT MOTION
● Pitch about the lateral axis through elevators
○ Pitch down is nose down
○ Pitch up is nose up
● Roll about the longitudinal axis through ailerons
○ Roll left is left wing down
○ Roll right is right wing down
● Yaw about the normal/vertical axis through rudder
○ Yaw left is nose left
○ Yaw right is nose right
● All motion acts through the centre of gravity
AIRCRAFT COMPONENTS
● Spinner
● Propeller
● Engine owl
● Fuselage
● Landing gear or undercarriage
● Wing strut or lift strut
● Wing or mainplane
● Ailerons
● Flaps
● Horizontal stabiliser or tailplane
● Elevator
● Vertical stabiliser or fin and dorsal
● Rudder
,FORCE
● A push or pull attempting to change the state of motion of something
● Has magnitude, a point at which it is applied and a direction acting
● Represented with a vector
VECTOR
● Force represented as a line
RESULTANT
● A vector with the same overall effect as the combination of other
vectors
EQUILIBRIUM
● When speed or direction are not changing
PRESSURE
● Force acting over an area (i.e. force divided by area)
WING LOADING
● Aircraft weight divided by wing area
● A form of pressure
WORK
● Force multiplied by distance (i.e. small force over a large distance, or
large force over a small distance)
● Therefore, if drag is the force in question, it must be kept at a
minimum to produce the largest distance (i.e. range)
POWER
● The rate at which work is being done (i.e. work divided by time)
● Therefore, if you consider fuel flow as a measure of power, minimum
, ●
power means minimum fuel flow, and thus the longest time to
exhaustion (i.e. endurance)
● RPM is also a measure of power, therefore minimising RPM ensures
maximum endurance
● Power is proportional to speed to the power of 3
○ For example, to travel at twice the speed, 8 times the power is
required (2^3 = 8)
KINETIC ENERGY
● Energy, being the ability to do work, because of motion
● 1/2*m*v^2
STATIC PRESSURE
● Pressure applied to a surface from the motion of molecules in gas
● At sea level, in ISA conditions:
○ 14.7 psi
○ 29.92 inches of Mercury
○ 1013.25 hPA
● Measured by the static port on aircraft
DYNAMIC PRESSURE
● Additional pressure due to the kinetic energy of gas in movement
● Source of aerodynamic forces
● Measured by the airspeed indicator
TOTAL PRESSURE
● Static pressure plus dynamic pressure
● Measured by the pitot tube
PITOT TUBE
● Collects a sample of the oncoming airstream and guides it into a
dead-end capsule
, ● Measures total pressure
STATIC PORT
● Collects a sample of the airstream perpendicular to airflow and
guides it into the space surrounding the capsule
AIRSPEED INDICATOR
● Measures the pressure difference between the pitot tube and static
port to assume the dynamic pressure, which is proportional to
airspeed
● Output is known as indicated airspeed
● Subject to position and instrument error
POSITION ERROR
● Arises when the pitot tube is not directly parallel with airflow and/or
the static port reads incorrectly due to airspeed or attitude changes
in flight
INSTRUMENT ERROR
● Internal components of the airspeed indicator preventing the
instrument from providing an accurate reading
CALIBRATED AIRSPEED
● Indicated airspeed corrected for position and instrument error
● Also rectified airspeed
● Insignificant for most VFR GA aircraft
● Subject to density error
TRUE AIRSPEED
● Calibrated airspeed corrected for density error
DENSITY ERROR
