Download Aerodynamics - Cathay Pacific "I Can Fly"

AERODYNAMICS
Aerodynamics is the science of air flow and the motion of aircraft through the air.
In a level flight, the ‘weight’ and ‘lift’ of the aircraft respectively pulls and holds it in
the air.
Hence, the aircraft maintains the same height when the two forces – weight
and lift balance each other. If,
•
– the plane will speed up
•
– the plane will slow down
•
– the plane will climb
•
– the plane will descend
The top surface of a wing is more curved than the bottom. If two air particles split up
at the tip of the wing and come back at the trailing edge at the same time, the
particle on top must be travelling faster, given the top has a larger surface than the
bottom.
The fundamental of fluid dynamics states that as the speed of a fluid flow
increases, its pressure decreases. While the faster moving air develops a lower
pressure on the top surface, the slower moving air maintains a higher pressure on the
bottom surface. This pressure difference essentially ‘sucks’ the wing upward.
AERODYNAMICS
If the ‘standard shape’ of the wing is deformed, for example, if there is ice on the
surface of the wings, the ‘lift-producing capability’ will be greatly reduced or may
totally disappear. The aircraft may not be able to take-off at all.
Wing is a very important aspect of the aviation field. All Cathay Pacific pilots wear a
pin that bears the shape of a pair of wings.
Apart from holding the aircraft in the air, airflow can also be used to control the
direction of the aircraft when the airflow hits the control surfaces.
There are three types of control surfaces that can steer an aircraft’s movement,
namely, the Elevator, the Rudder and the Aileron.
AERODYNAMICS
The Elevator is controlled by the forward/backward movement of the control column.
Pulling the controls will cause the elevator to deflect upwards, causing the aircraft to
pitch upwards about the lateral axis.
The Ailerons are controlled by the sideways movement of the control column.
Turning the controls to the right will cause the right aileron to deflect upwards and
the left one to deflect downwards. This causes the plane to roll right about the
longitudinal axis.
AERODYNAMICS
The Rudder is controlled by the movement of the rudder pedals. Pushing the left
pedal will cause the Rudder to deflect to the left. The plane will yaw left about the
normal axis.