technology

Explain it: How Do Airplanes Fly?

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Explain it

... like I'm 5 years old

Airplanes fly by utilizing the principles of aerodynamics, a branch of physics that deals with the motion of air and the way it interacts with solid bodies, like an aircraft. At the simplest level, think of an airplane as a large paper plane. When you throw a paper plane, it moves forward due to the force of your throw and it glides through the air due to its shape.

The real airplanes we see in the sky operate on similar principles. They move forward due to the force of their engines and they glide due to their wing shape. The wings are designed in a special shape - flat on the bottom and curved on the top. When the plane moves forward, air travels faster over the curved top than the flat bottom. This creates lower pressure above the wings than below, causing lift.

Imagine you're in a swimming pool with a flat board. If you push the board under the water and let go, it'll pop back up to the surface. That's similar to how an airplane's wings work in the air. The wings push down on the air, and the air pushes up on the wings, keeping the plane aloft.

Explain it

... like I'm in College

Airplanes rely on four fundamental forces to fly: lift, gravity, thrust, and drag. Lift counteracts the downward force of gravity, while thrust counteracts drag, the resistance faced by the plane as it moves through the air.

The engines, whether jet engines or propellers, generate thrust. The specific design of the wings, known as airfoil, plays a critical role in generating lift. The top surface of the wing is curved, while the bottom surface is flatter. As the plane moves, air travels faster over the top surface than the bottom, reducing the air pressure above the wing. The higher pressure beneath the wing lifts the plane.

EXPLAIN IT with

To understand how planes fly using Lego, let's build a simple model. The base represents the fuselage (the main body of the plane), the flat pieces on either side are the wings, and the small, round pieces at the back are the engines.

The engines propel the plane forward, overcoming drag. The wings, with their special shape, push air down. Thanks to Newton's third law of motion, the air pushes back up on the wings, creating lift.

Now, let's tilt the plane's nose slightly upward. This is the 'angle of attack'. A greater angle of attack makes the wings push more air downwards, which means more lift. But if we tilt the nose up too much, the plane would stall.

Just as with building a Lego model, flying a plane is all about finding the right balance, keeping the forces of lift and gravity, and thrust and drag, in check.

Explain it

... like I'm an expert

On a more complex level, the principles of fluid dynamics come into play when discussing how airplanes fly. The lift an airplane experiences is a result of Bernoulli’s principle, which explains how air pressure decreases as the speed of the airflow increases, and vice versa.

The shape of the wing, or airfoil, is designed to take advantage of this principle, with the curvature of the upper surface causing air to travel faster and create less pressure. This, combined with the slower moving, higher pressure air beneath the wing, creates lift.

The angle of attack, or the angle between the wing's chord line and the oncoming airflow, also significantly affects lift. As the angle increases, lift increases – up to a point. Beyond this point, known as the critical angle of attack, the airflow becomes disrupted and lift decreases, leading to a stall.

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