The Bernoulli Principle
The common explanation
given to those curious about how an airplane wing produces lift uses the
Bernoulli Principle. This is the
concept that because of the airfoil shape of a wing, the air traveling over
the top of the wing must travel faster than the air going under the wing
because it has to travel a farther distance. The resulting difference in pressure between the two
(higher pressure under the wing) creates lift, keeping the plane in the
air.
The Bernoulli Principle applied to an airfoil (http://ldaps.ivv.nasa.gov/Physics/Images/Engineering_Manual9.gif) This explanation is unsatisfactory in a number of ways. It does not consider or explain the important role that the angle of attack plays in flight, nor does not explain how planes can fly upside down (where according to the Bernoulli Principle, the pressure would actually be higher on the top of the wing, pushing the plane down to the ground!). For some interesting arguments and calculations refuting the Bernoulli Principle as a sound explanation for lift in an airplane, check out Gail Craig’s book “Stop Abusing Bernoulli! How Airplanes Really Fly” available from Regenerative Press (see bibliography). |
