Bernoulli's Principle of Lift
Air Planes are able to fly because of lift which is what holds an airplane up. Lift is created by differences in air pressure explained by Bernoulli's principle. It states that air moving fast has a lower air pressure than air moving slower underneath.
The way the airplane's wings are shaped forces the air going over the top of the wings to speed up in order to reach the end edge of the wing at the same time as the air traveling under the wing. The bottom air has to travel a shorter difference to the end of the wing so that the air does not have to travel fast.
These varying speeds create a difference in pressures. This air pressure difference exerts a upward force on the wings that keeps the airplane in the air.
The Causes of Stalls and Spins
Stalls are caused when several conditions are true. One is that the airplane has to have a high angle of attack. Angle of attack is the angle at which a plane is climbing or falling where flying level is an angle of 0 degrees. So a high angle of attack would mean that the plane's nose is pointing up to the sky. The angle at which the aircraft stalls depends on how fast the plane is going. The faster the speed the higher the angle necessary to cause a stall.
The stall occurs when the angle of attack becomes so great that the wings can no longer produce lift. The wings no longer produce lift because the air flowing over the top of the wing begins to whip around and cause vortexes. This means the air is no longer moving fast enough to cause the necessary difference in pressure to produce lift.
Spins are a form of a stall. The difference is that in this case one wing stalls while the other does not. This causes the plane to begin to spin rapidly down.
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