Pressure on a Wing
What do we mean by differences in
pressure? What do we mean by lift?
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Smaller/Weaker/Lower
Pressure
Greater/Stronger/Higher Pressure |
Lets look at a wing. See how the wing of this plane is angled slightly upward? The wing has something called an “angle of attack.” As the plane moves forward, air pushes on the bottom of the wing resulting in an increase pressure. The
wing moves up as it pushes air down. Meanwhile, on top of the wing, the rushing air creates a low pressure.
The difference between the high and the low pressure generates lift. |
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Have you ever wondered why an airplane wing is curved? The curvature is called “camber.” Camber allows airplanes to generate lift at slower airspeeds. Camber also helps to accentuate the differences in pressure on a wing- In a sense, camber increases lift. |
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Faster Air = lower pressure
Slower air = higher pressure |
Here
is the secret of lift: For an airplane to fly there must be greater/stronger/higher
air pressure under a wing and smaller/weaker/lower air pressure on top. Bernoulli’s
Principle, states that pressure decreases when air moves faster. Air moves
faster over the top of a wing, which results in an area of lower pressure.
Meanwhile, the bottom of the wing experiences higher pressure. Camber increases the difference in air
pressure between the top and bottom surfaces. |
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Here’s a common mistake: Some people think lift is due solely to the camber of the wing. Not true. A cambered wing only increases the differences in pressure that create lift. The dominant factor in the creation of lift is the angle of attack of the wing. |
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Lift
is best explained by examining Newton’s laws. For instance, according to Newton’s 3rd
Law, wings push on the air and the air pushes back with an equal and
opposite force. The result of tons of air being pushed down is that the
plane is pushed up! The camber of a wing and its angle of attack deflect
air downward. The following link explains how this occurs in greater detail: How a wing generates lift |
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Have
you ever wondered how a plane with a cambered wing can fly upside down? It’ll
fly as long as it has a sufficient angle
of attack to create lift. The plane must have a higher air pressure under
it and lower air pressure above it. |
The
Wright brothers did a lot of tests to determine which wing shape would work the
best. They developed wings that would generate great differences in pressure
and create lift.