2torial #0742:
Learn2 Understand How Airplanes Work

Wing it

How can a 100-ton hunk of metal move through the air as if it were weightless? It flies in the face of our everyday experience. After all, if we drop a glass weighing just a few ounces, it goes crashing to the ground in a split second.

This 2torial explains the nuts-and-bolts principles that make the miracle of flight possible. So read on--it may put you at ease the next time you're on the runway.

When you see a plane flying through the air, it looks like it's floating on nothing at all, but actually it's moving through a fluid. That's right, what looks like empty space is full of atoms and molecules--mostly nitrogen, oxygen, and carbon dioxide (and, these days, more and more carbon monoxide). In fact, a cubic foot (about .03 cubic meters) of air at sea level weighs a little more than an ounce (or about 35 grams).

If you throw a rock through the air, it moves more or less in a straight line, except perhaps as it curves toward the ground because of gravity. But if you dump a pail full of water on the ground, it moves in much more complicated ways. In fact, fluid dynamics (i.e. the study of the way fluids move) is its own branch of physics.

This 2torial draws on some of the most basic principles of fluid dynamics. They may not be familiar, but they're simple to grasp and essential to understanding the phenomenon of flight.