How does an airplane fly?

One of the questions that every air transport user asks (and not just www.fofly.com trainees!) is this: How can a plane fly? How can a mass of several hundred tons keep itself aloft? The answer to this question is called "lift", but this physical law is little-known, and I'm going to try to explain it to you as simply as possible.

What is lift?

Lift is the key to understanding how an aircraft flies. It's a force exerted on the top of the wing. It depends on the speed, size and shape of the wing. In an airliner, you'll notice that the top of the wing (upper surface) is more "bulging" than the bottom (lower surface). This means that the air generated by speed travels a greater distance between the beginning of the wing (leading edge) and the end of the wing (trailing edge) on the upper wing (as it is more "bulged") than on the lower wing (straighter).

How does the air lift the plane?

Nevertheless, a physical law confirms that 2 air molecules, one passing through the top and the other through the bottom of the wing, will arrive at the same moment at the "trailing edge". This is indeed possible if the air molecule at the top is moving faster than the one at the bottom! Which is indeed the case! This means that the air passing over the top of the wing will be going faster than the air passing underneath. This speed over the wing also reduces pressure. So we find ourselves with more pressure under the wing than on it! This pressure difference creates an upward force: Lift. It's this force that keeps every plane flying!

Still in doubt?

Use this little experiment to visualize the physical law that explains how an airplane flies. Take a sheet of paper and hold it crosswise by its ends. The sheet will fall naturally under the force of its own weight. Now blow on the top of the sheet, and what happens? The sheet lifts! Like an airplane wing, you've got more speed on top of the sheet, so less pressure, and so you've just created lift!!!! It's this force that lifts your sheet. On another scale, it's the same law of physics that enables airplanes to fly.