How is an airplane wing designed to lift the airplane.?

Answer 1

If straightened out, the top surface of the wing is longer than the bottom one. When air flows over the wing, it must travel faster over the top of the wing so there is less air pressure. higher air pressure on the bottom and lower air pressure on the top= LIFT. The higher the Airspeed the lower the air pressure is called Bernoulli's principle.

Answer 2

A wing creates lift by imparting a downward momentum to the air flowing above and below it. The rate of change of momentum is equal to Force (Newton's 2nd law), and therefore a reaction force pushes the wing up, producing lift (Newton's 3rd law).

The imparting of this downward momentum ("downwash") to the air results from an air pressure differential above/below the wing. If you know the pressure above the wing and the pressure below the wing, and the wing area, you can calculate the lift force on the wing since Force = Pressure x Area. If you don't know the pressures, you can get a rough estimate if you know what the average air velocities are above and below the wing. A wing creating lift will have higher speed air flowing over the top of it than flowing below it. By employing Bernoulli's Principle, you can calculate a pressure difference corresponding to the difference in velocity.

An airfoil shape is effective in generating lift since it helps to keep the air flowing smoothly around the wing, making the wing more effective in diverting the air downwards. However, even a perfectly flat wing can create lift (such as in a toy balsa wood glider). However a flat wing isn't practical for a full sized airplane since it's not quite as effective in producing lift, it produces a lot of drag and it stalls abruptly.

Note that there is no requirement that the air molecules separating at the leading edge and flowing below the wing meet up with the same molecules that flow over the top. This is called the "equal transit time theory" and is a popular science myth that unfortunately has found it's way into flight manuals and even some undergraduate texts. However, aerodynamicists have known ever since they started doing wind tunnel testing that the air flowing over a lifting wing reaches the trailing edge sooner than the air below it. This is true even for a perfectly flat wing. This can be explained in terms of the circulation theory, which is an advanced concept.

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Answer 3

The "air-foil" design creates a low pressure zone above the wing as the air flowing over the wing has to travel farther/faster than the air underneath the wing. The "angle of attack", the angle the wing is tilted up at the front help to create more lift, especially at lower speeds. Depending on the angle of the wing/wing surface area to wt. the "stall speed" ( minimum airspeed to sustain flight) can vary. Wings on race cars work the same way but are flipped upside down to produce downforce.