How Do Airplanes Fly?
In semi-scientific terms, airplanes fly using the basic force of transferring the forward momentum of rolling along the runway into lift that takes the plane into the air. However, there has to be another very important factor for this miraculous even to take place. This factor is widely known as the Bernoulli effect. This is accomplished by designing the wings of the plane so that the top surface of the wing is longer than the bottom of the wing, from lead edge to trailing edge.
When air flows under the wing and over the wing, the pressure on the top side is less than on the underside. The difference in pressure provides the lift – simply put, this forces the plane upward. An efficient use of momentum transfer and Bernoulli effect is made possible by proper design. The wings must be carefully measured and angled correctly for this to take place.
The effect is named for Daniel Bernoulli, who published his work in 1738. He was working with a concept called fluid dynamics. Air is considered fluid or capable of flowing. (This is different from the definition many people think of when they hear the word fluid. Both gases and liquids can be fluid.)
According to scientific literature, Bernoulli’s work was based on the idea of energy conservation. With a steady flow or situation of fluidity, the energy should be the same at all points. This changes when something interferes with the consistency of the flow. In the case of the airplane, the wing and its shape have a lot to do with how the flow of air makes it from the leading edge of the wing to the trailing edge.
Wing design has changed a lot over the decades since men first took to the air in their crudely built craft. The best designs for wings show that the top of the wing is curved while the bottom is straighter. This curve and the longer distance provide the upward pressure or lift, as described earlier. Airplanes can take off from the ground only if they achieve a certain speed (forward motion) first. The faster the plane moves, the faster the wing moves of course. The difference in pressure on top and bottom of the wing is greater, providing the lift necessary to get the huge object off the ground.
The propeller of a plane or the thrust of the jet engine provide the forward momentum needed both on the ground and in the air. Working against this and against the lift provided by the wings are air resistance and gravity. Pilots control this process during takeoff with forward speed and, in newer craft, shaping the wing.
They also control the process when flying, to change direction and altitude. Pilots can also control forward momentum, speed and wing shape when preparing to land. They must counteract the Bernoulli effect, or work with it in a way that is opposite that of the takeoff.
It seems that simple mechanics and an understanding of air pressure allows man to fly in a plane.
Category: Science