Lifting power of the wing and its application in aviation
Mastering the airspace of mankindbeginning with the help of balloons, that is, aircraft with an average density lower than that of air. However, the discoveries in the field of aerodynamics created the conditions for the implementation of fundamentally different means for moving in the atmosphere, and led to the emergence of aviation.
For each airplane flying in the sky, actfour forces: gravity, friction, engine thrust and another, holding it in the air. However, such an aircraft, like a glider, does without a motor, and uses to move the energy of atmospheric fluxes. So what keeps the heavy aircraft from falling under the influence of gravity and compensates it? A vector directed upwards is the lifting force that occurs when the wing surfaces are washed by air. It is not difficult to explain its nature. If you carefully consider the wing of the aircraft, it turns out that it is convex. During the movement of the air molecules from below pass a smaller distance than the top. This leads to the fact that the pressure under the plane becomes greater than above it. Above the wing, the air "stretches", becoming more discharged than under a flat bottom surface. It is this pressure difference that is the lifting force that pushes the aircraft up, overcoming the force of gravity.
The first aircraft manufacturers faced the needsolving a number of technical problems that require new solutions at the time. It was clear that the lift of the wing depends on the geometry of its velocity profile. At the same time, the airplane moves unevenly in the air. In addition, for detachment from the ground and take-off required more energy than for flying at a constant altitude. The upper layers of the atmosphere are more discharged, which also affects the structural properties of the structure. Decrease and landing required special piloting regimes. The solution to the problem found was the possibility of changing the characteristics of the wing profile by means of its mechanization. The structure included movable elements, called flaps.
When they are deflected upward, the lifting force is reduced,and when they are lowered, it increases. Modern aircraft have a high degree of mechanization of the wing - in their design many units and assemblies are used, which allow to effectively control aviation equipment at different speeds and under different conditions. The front part is equipped with slats, at the bottom, as a rule, there are brake flaps, but the principle remained the same as that used in the first airplanes: the lift of the aircraft wing depends on the difference in the speed of the flow of air near the upper and lower surfaces.
Flaps of the mechanized wing during takeoffmaximum omitted, which allows you to reduce the length of the takeoff run. When planting their position is the same, then it can be carried out with a minimum speed. When performing horizontal maneuvers, the pilot, with the control knob or the hand wheel, changes the position of the flap so that the lifting force corresponds to his intentions to lift the aircraft higher or lower. When flying at a given altitude with a constant speed, the elements of the mechanization of the wing are in neutral, that is, the middle position.