Those people who flew airplanes and paid attention to the wing of an iron bird while it sits down or takes off, probably noticed that this part begins to change, new elements appear, and the wing itself becomes wider. This process is called wing mechanization.
general information
People always wanted to drive faster, fly faster, and so on. And, in general, with the plane, this quite happened. In the air, when the device is already flying, it develops tremendous speed. However, it should be clarified that a high speed indicator is acceptable only during direct flight. During takeoff or landing, the opposite is true. In order to successfully raise the structure into the sky or, conversely, put it in, high speed is not needed. There are several reasons for this, but the main one is that to disperse you will need a huge runway.
The second main reason is the tensile strength of the aircraft chassis, which will be passed if you take off in this way. That is, in the end it turns out that for high-speed flights one type of wing is needed, and for landing and take-off it is completely different. What to do in this situation? How to create two pairs of wings that are fundamentally different in design from the same aircraft? The answer is no way. It was such a contradiction that pushed people to a new invention, which was called wing mechanization.
Attack angle
In order to explain clearly what mechanization is, it is necessary to study another small aspect, which is called the angle of attack. This characteristic has the most direct relationship with the speed that the aircraft is capable of developing. It is important to understand here that in flight almost any wing is at an angle with respect to the flow incident on it. This indicator is called the angle of attack.
For example, to fly at low speed and at the same time maintain lift, so as not to fall, you have to increase this angle, that is, to pull the nose of the plane up, as is done on takeoff. However, it is important to clarify that there is a critical mark, after the intersection of which the flow cannot be held on the surface of the structure and breaks from it. This is called pilot separation of the boundary layer.
This layer is called the air flow, which is in direct contact with the wing of the aircraft and creates aerodynamic forces. With all this in mind, a requirement is being formed - the presence of large lifting power at low speed and maintaining the required angle of attack in order to fly at high speed. It is these two qualities that the wing mechanization combines in itself.
Performance improvement
In order to improve take-off and landing performance, as well as ensure the safety of the crew and passengers, it is necessary to reduce the take-off and landing speed to the maximum. It is the presence of these two factors that has led designers of the wing profile to resort to the creation of a large number of different devices that are located directly on the wing of the aircraft. A set of these special controlled devices began to be called wing mechanization in the aircraft industry.
The purpose of mechanization
Using such wings, it was possible to achieve a strong increase in the value of the lifting force of the apparatus. A significant increase in this indicator led to the fact that the run of the aircraft during landing on the runway decreased significantly, as well as the speed at which it lands or takes off. The purpose of wing mechanization is also that it improved stability and increased the controllability of such a large aircraft machine as an airplane. This is especially noticeable when the aircraft gains a high angle of attack. In addition, it is worth saying that a significant decrease in landing and take-off speeds not only increased the safety of these operations, but also made it possible to reduce the cost of building runways, since it became possible to reduce them in length.
The essence of mechanization
So, speaking in general, the mechanization of the wing led to the fact that the take-off and landing parameters of the aircraft were significantly improved. This result was achieved due to a strong increase in the maximum lift coefficient.
The essence of this process is that special devices are added that enhance the curvature of the wing profile of the device. In some cases, it also turns out that not only the curvature increases, but also the immediate area of this element of the plane. Due to changes in these indicators, the streamlining picture is also completely changing. These factors are decisive in increasing the coefficient of lift.
It is important to note that the design of the wing mechanization is carried out in such a way that in flight all these parts are controllable. The nuance lies in the fact that at a small angle of attack, that is, when flying already in the air at high speed, they are not actually used. Their full potential is revealed precisely when landing or taking off. Currently, there are several types of mechanization.
Shield
The shield is one of the most common and simplest parts of the mechanized wing, which quite effectively copes with the task of increasing the coefficient of lift. In the wing mechanization scheme, this element is a deviating surface. When the position is retracted, this element is almost adjacent to the lower and rear parts of the wing of the aircraft. With the deviation of this part, the maximum lifting force of the apparatus increases, because the effective angle of attack, as well as the concavity or curvature of the profile, change.
In order to increase the efficiency of this element, it is structurally executed so that when it deviates, it moves back and at the same time to the trailing edge. It is this method that will give the greatest efficiency of suction of the boundary layer from the upper surface of the wing. In addition, the effective length of the increased pressure zone under the wing of the aircraft increases.
Design and purpose of mechanization of an airplane wing with slats
It is important to note immediately that a fixed slat is mounted only on those aircraft models that are not high-speed. This is because this type of design significantly increases drag, and this dramatically reduces the ability of the aircraft to develop high speed.
However, the essence of this element is that it has such a part as the deflected toe. It is used on those types of wings that are characterized by a thin profile, as well as a sharp leading edge. The main purpose of this sock is to prevent the flow from breaking at a large angle of attack. Since the angle can constantly change during the flight, the toe is also fully controllable and adjustable so that in any situation it is possible to choose a position that will keep the flow on the wing surface. At the same time, aerodynamic quality can also increase .
Flaps
The wing mechanization scheme with flaps is one of the oldest, as these elements were among the first to be used. The location of this element is always the same, they are located on the rear of the wing. The movement that they perform is also always the same; they always fall strictly down. They can also be pulled back a little. The presence of this simple element in practice has been very effective. It helps the aircraft not only during take-off or landing, but also when performing any other maneuvers during piloting.
The type of this element may vary slightly depending on the type of aircraft on which it is used. The mechanization of the wing of the TU-154, which is considered one of the most common types of aircraft, also has this simple device. Some aircraft are characterized by the fact that their flaps are divided into several independent parts, while some have one solid flap.
Ailerons and Interceptors
In addition to those elements that have already been described, there are also those that can be attributed to secondary. The wing mechanization system includes such minor parts as ailerons. The work of these parts is carried out differentially. Most often, a design is used such that on one wing the ailerons are directed up, and on the second they are directed down. In addition to them, there are also such elements as flaperons. In their characteristics, they are similar to flaps; these details can deviate not only in different directions, but also in the same one.
Additional elements are also interceptors. This part is flat and is located on the surface of the wing. The deviation, or rather the rise, of the interceptor is carried out directly into the stream. Because of this, there is an increase in the drag of the flow; therefore, the pressure on the upper surface increases. This leads to the fact that the lifting force of a given wing decreases. These wing elements are sometimes also called bodies for controlling the lift of an aircraft.
It is worth mentioning that this is a rather brief description of all the structural elements of the mechanization of an aircraft wing. In fact, it uses a lot more various small details, elements that allow pilots to fully control the process of landing, take-off, the flight itself, etc.