Off-Topic How do airplanes stay in the air?

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Airplanes stay in the air because of four main forces that work together: lift, weight (gravity), thrust, and drag.

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The most important force that keeps a plane flying is lift, which is created by the shape of the wings and the movement of air around them.

1. The Four Forces of Flight ​

Lift (Keeps the plane in the air)​

• Lift is created by the wings using a principle called Bernoulli’s Principle.
• The wings have a curved upper surface and a flatter lower surface (airfoil shape).
• Air moves faster over the top of the wing and slower underneath, creating higher pressure below and lower pressure above.
• This difference in pressure pushes the plane upward, keeping it in the air.

Weight (Pulls the plane down)​

• Gravity pulls the airplane toward the Earth.
• To stay in the air, lift must be greater than or equal to the plane’s weight.

Thrust (Moves the plane forward)​

• Engines or propellers generate thrust to push the plane forward.
• Faster-moving air over the wings creates more lift.

Drag (Slows the plane down)​

• Air resistance (drag) pushes against the airplane as it moves forward.
• Planes are designed to be aerodynamic to reduce drag.

2. How Wings Generate Lift (Bernoulli’s Principle & Newton’s Laws)​

• Bernoulli’s Principle: Faster air on top = lower pressure, slower air below = higher pressure → Creates lift!
• Newton’s Third Law: The wings push air downward, and the air pushes back up on the wings → More lift!

3. How Planes Stay in the Air & Change Direction​

• Pilots control the wings and tail using movable surfaces:
  Ailerons (on wings) – Control tilting (rolling) left or right.
  Elevators (on tail) – Control climbing or descending.
  Rudder (on tail) – Controls turning left or right.

4. Why Don’t Planes Fall?​

As long as lift is greater than weight and thrust is greater than drag, the plane will stay in the air. If lift or thrust decrease (like when an engine fails), the plane descends but can still glide safely.