## Tuesday, 11 October 2011

### Aerodynamics

FORCES OF FLIGHT

Gravity – The force that causes things to fall to the ground.

Lift - The pressure of air that keeps something like an aircraft in the air.
Thrust – This is the force that propels or drives an aeroplane forward.

Drag - Is created by friction between the air and surface.

Lift and Thrust are seen as positive forces in flight, whereas gravity and drag are seen as negative forces.

Gravity and lift are always fighting against each other and thrust and drag are always fighting each other in flight.

The effect that drag and thrust have on an object is an interesting thing though:

• If drag is greater that thrust the aeroplane’s speed decreases
• If drag is less that thrust then the aeroplane’s speed increases
• If the thrust and drag are equal then the aeroplane will fly at a constant speed.

How does a plane fly?

Pretend your arms are wings. If we place one wing down and one wing up we can use the roll to change the direction of the plane. We are helping to turn the plane by yawing toward one side. If we raise our nose, like a pilot can raise the nose of the plane, we are raising the pitch of the plane.  Using all of these together is how we control the flight of the plane.

A pilot of a plane has special controls that can be used to fly the plane. There are levers and buttons that the pilot can push to change the yaw, pitch and roll of the plane.

To roll the plane to the right or left, the ailerons are raised on one wing and lowered on the other. The wing with the lowered aileron rises while the wing with the raised aileron drops.
Pitch is to make a plane descend or climb. The pilot adjusts the elevators on the tail to make a plane descend or climb. Lowering the elevators caused the airplane's nose to drop, sending the plane into a down. Raising the elevators causes the airplane to climb.
Yaw is the turning of a plane. When the rudder is turned to one side, the airplane moves left or right. The airplane's nose is pointed in the same direction as the direction of the rudder. The rudder and the ailerons are used together to make a turn
A couple of experiments for aerodynamics