Conclusion
It
is almost unbelievable to think that something as light as air could create
enough force to lift an extremely heavy object such as a jumbo jet, but it is
true. In order to create this
lift, however, the wings must displace an enormous amount of air. For instance, a low estimate of the
amount of air that must be diverted down in order to lift something as small
as a Cessna 172 weighing about 2,300 pounds and flying at about 110 knots is
2.5 tons of air per second! That
would mean that all the air within 9 feet above the wing would have to be
diverted downwards (Anderson and Eberhardt, 1999). That is a lot of air! The popular Bernoulli Principle would not be able to
explain the diversion of air necessary to create such lift. Now that you know the real physics
behind lift of an airplane, the next time you board an airplane to sunny
Hawaii (or even Italy) for Christmas vacation, you can feel confident that
more is holding the plane up in the air over that big, cold body of water or
rugged mountain range below than just some high pressure air on the underside
surface of the wing!
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