When something flies, it overcomes the force of gravity and
moves through the air. Birds and aeroplanes fly using curved aerofoil wings
that produce an upward force called lift. When birds flap their wings, they
generate lift and move their bodies forwards at the same time. Aeroplanes
generate lift with their aerofoil wings, but need engines to move them
forwards.
An aerofoil wing generates lift because of its curved shape. As the
wing moves forwards, air has to travel faster over the curved top of the wing
to keep up with the air moving underneath it. This lowers the air pressure
above the wing and creates an upward force that overcomes the
aeroplane’s weight. An aerofoil also creates drag that pulls the
aeroplane backwards.
Pilots control and steer an aeroplane using the ailerons, rudder,
and elevators. These are swivelling flaps built into the wings and the tail of
the aeroplane.
The pilot can bank (roll) the aeroplane by using the ailerons. For
example, he turns to the right by tilting the right aileron up and the left
aileron down. This increases lift on the left wing, reduces lift on the right
wing, and makes the plane bank and turn to the right.
The rudder is a vertical flap on the rear edge of the tailfin. The
pilot can swivel it from side to side to help turn the aeroplane to the left or
to the right without banking.
The elevators are horizontal flaps at the back of the tailfin. The
pilot can tilt them up or down to raise or lower the nose of the aeroplane, to
climb or dive.
