Physics of Lift

1433 Words3 Pages

Lift is a commonly used term to describe "something" that results in objects moving upwards against the force caused by gravity. This "something" is actually a force in itself. Lift is one of the four main forces that act upon all objects that move through the air. These four forces are:

# Lift - an upward force on the object

# Weight - a downward force due to the acceleration of gravity

# Thrust - a forward force (propulsion)

# Drag - a force caused by resistance that acts in the opposite direction of thrust

Lift is a simple concept to grasp, yet the reason it exists is a complex one. To this day there is still great debate over what is the cause of lift. There are several popular explanations given which are commonly found in student textbooks, and even pilot training manuals, yet these popular explanations do not stand up to serious physics analysis. The most common of these arguments is based off of Bernoulli’s Principle.

As it has been named, "Bernoulli’s" argument states that the reason lift is created in wings is that the upper surface of the wing is curved, and therefore longer than the underside of the wing (In truth, Bernoulli had nothing to do with this explanation of lift, it is only attributed to his principle). The argument goes on to say that if the upper surface is longer than that of the bottom, the air flowing over the upper surface must travel faster as it has farther to travel. Using Bernoulli’s Principle this explanation says that because the air traveling over the top of the wing is moving faster than the air under the wing the air above the wing exerts less pressure on the wing than the air under the wing. If there is less pressure above the wing then the air under the wing will push upwards on the...

... middle of paper ...

...del for lift, even though it works in reality.

In conclusion it can be seen that lift is derived from the fact that for there to exist a lifting force created in the wings the wings must exert a force on the air around them. The wings are able to do this due to the viscosity of air and the Coanda effect. By manipulating the wing's curves and angle of attack a pilot may preform great stunts and feats not possible if lift were to be explained through other incorect models.

More information about lift, as well as a very detailed explanation of exactly how a wing interacts with the air around it can be read in the journal article: "A unified viscous theory of lift and drag of 2-d thin airfoils and 3-d thin wings" author Yates, John, published by National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program in 1991.

More about Physics of Lift

Open Document