1. Read the text.

Why an Aeroplane Flies

Do you ever look up and see a great jet airliner passing overhead and wonder just how such a big, heavy aeroplane manages to get into the air in the first place?

You must remember that air has an atmospheric pressure that varies according to how high you go. At sea level the air is much denser than it is higher up. The lift that an aeroplane requires to get it off the ground in the first place is provided in part by the special aerofoil shape of the wings and in part by the aeroplane’s forward thrust. So the aeroplane is actually lifted off the ground by the weight of the air pressing up underneath it.

There are, in fact, five factors that affect the way an aeroplane climbs. They are, the shape of the wings, their area, the density of the air, the speed of the forward thrust, and the angle of attack. That is the angle at which the aeroplane rises into the air.

If the pilot took the plane up at too steep an angle, it might stall, and if it stalled while it was taking off, it would almost certainly crash. A plane might also stall in level flight – if the pilot flew too slowly, for instance. So when the plane is flying in a straight line, at a constant height, the lift must always equal the weight.

Imagine an aeroplane was flying straight ahead at a particular height. If the pilot increased his speed, he would have to adjust the angle of attack by putting down the nose a fraction, to compensate. Conversely, if he reduced his speed, he would have to compensate by raising the nose slightly.

Taking off

The pilot taxies the aircraft out onto the runway and the plane moves forward at increasing speed until the flying speed is reached. When the plane is moving fast enough, the pilot eases back the stick, the nose lifts into the air and the plane leaves the ground.

When the required height is reached, the pilot pushes forward the stick, lowering the nose and adjusts the speed so as to ensure level flight.

An aeroplane is designed to be as streamlined as possible, in order to cut the drag (backward pull) to a minimum.

Wing section

The rudder on the tail and the flaps on the wings and the tail provide the means to control the aeroplane while in flight. The rudder is used to turn the aeroplane, and the flaps to slow the plane when it is coming in to land.

The propeller of a piston-engined aircraft provides the forward thrust. The propeller blades are curved like an aerofoil.

2. Reading Comprehension

Decide whether the following statements are true (T) or false (F):

1. The air is less dense at 100,000 feet than it is at sea level. ( )

2. The shape of the wings affects the way an aeroplane climbs. ( )

3. An aeroplane must always reach a certain speed on the runway before it can take off. ( )

4. If the wing flaps were damaged the pilot would have no trouble in landing the plane. ( ).

5. The angle of attack is the angle at which the plane comes in to land. ( )

6. The pilot of a light aeroplane pushes forward the stick when coming in to land. ( )

7. If an aeroplane flies too slowly it might stall. ( )

8. The more streamlined the shape of an aeroplane the more drag there will be. ( )