The tail unit of the aircraft. A photo. Main functions.
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The tail unit of the aircraft. A photo. Main functions.

The tail unit of the aircraft. A photo. Main functions.

Empennage - airfoils disposed in the tail section of the aircraft. They appear as a relatively small "wings" which are traditionally set in the horizontal and vertical planes, and are known as "stabilizers".

The tail unit of the aircraft. A photo. Main functions.

It is for this parameter empennage and divided, first of all - on the horizontal and vertical, respectively, with the plane in which is set. The classical scheme - one vertical and two horizontal stabilizer that are directly connected to the aft fuselage. That such a scheme the most widely used in civilian airliners. However, there are other schemes - for example, T-shaped, which is used on the Tu-154.

In this scheme, the horizontal tail is attached to the top of the vertical, and when viewed from the front or the back of the aircraft, it resembles the letter “T”, from which it got the name. There is also a scheme with two vertical stabilizers, which are placed on the ends of the horizontal tail, an example of an aircraft with this type of tail is the An-225. Also, the two vertical stabilizers have most of the modern fighters, but they are installed on the fuselage, since they have the shape of the fuselage somewhat more flattened horizontally compared to civilian and cargo aircraft.

Well, in general, there are dozens of different configurations of the tail unit and each has its advantages and disadvantages, which will be discussed more below. Even it is not always set in the rear of the aircraft, but this applies only to the horizontal stabilizer.

The tail unit of the aircraft. A photo. Main functions.

The tail assembly of Tu-154

The tail unit of the aircraft. Photo. Main functions. The tail unit of the aircraft.

The tail of the aircraft An-225

The principle of the tail. Main functions.

Now, the functions of the tail, why is it necessary? Since it is also called stabilizers, it can be assumed that they have something to stabilize. It is true, it is. The tail assembly is necessary to stabilize and balance the aircraft in the air, and another for the control plane along two axes - yaw (left-right) and pitch (up and down).

The tail unit of the aircraft. A photo. Main functions.

The vertical empennage.

Functions of the vertical stabilizer - stabilization of the aircraft. In addition to the above two axes, there is still a third - roll (rotation around the longitudinal axis of the aircraft), and so, in the absence of the vertical stabilizer, the bank is rocking the plane about a vertical axis, though swinging a very serious and totally uncontrolled. The second function - control of the yaw axis.

The back edge of the vertical stabilizer attached tiltable profile, which is controlled from the cockpit. It has two main functions of the vertical tail, absolutely does not matter the number, position and shape of the vertical stabilizer - these two functions they perform always.

The tail unit of the aircraft. A photo. Main functions.

Types of vertical tail.

Horizontal empennage.

Now about the horizontal tail empennage. It also has two main functions, the first one can be described as a balancing one. In order to understand what's involved in this, you can conduct a simple experiment. It is necessary to take some long object, for example a ruler and put it on one elongated finger so that it does not fall and does not slope neither back nor forward, i.e. Find its center of gravity. So, now the ruler (fuselage) has a wing (finger), it is not difficult to balance it. Well, now you need to imagine that tons of fuel are pumped into the line, hundreds of passengers get in, a huge amount of cargo is loaded.

Naturally, all this is perfectly downloaded the center of gravity is simply impossible, but there is a way. It is necessary to have recourse to the finger of the second hand and place it on top of the rear of the conditional line, then move the "front" toe to the rear. The result was a relatively stable construction. You can still do differently: put "back" finger under the line and move the "front" forward toward the bow. Both of these examples demonstrate the principle of operation of the horizontal tail.

More common is the first type, when the horizontal stabilizers create a force opposite to the lifting force of the wings. Well, their second function is the control on the pitch axis. Here everything is absolutely the same as with vertical plumage. In the presence of a divergent trailing edge profile, which is controlled from the cockpit and increases or reduces the force that creates a horizontal stabilizer due to its aerodynamic profile. Here it is necessary to make a reservation concerning the deflected trailing edge, because some aircraft, especially combat aircraft, have completely deflected planes, and not only their parts, this also applies to vertical tail, but the principle of operation and function does not change from this.

The tail unit of the aircraft. A photo. Main functions.

Types of horizontal tail.

And now about why designers are moving away from the classical scheme. Now a huge number of aircraft and their purpose with very different characteristics. And, in fact, it is necessary to disassemble a specific class of planes and even a particular plane separately, but to understand the basic principles will be just a few examples.

The first, the An-225, already mentioned, has a double offset vertical tail, for the reason that it can carry such a voluminous thing as the Buran shuttle that would shadow aerodynamically the only vertical stabilizer located in the center, and its efficiency was would be extremely low. The T-shaped Tu-154 also has its advantages. Since it is even behind the rear point of the fuselage, due to the sweep of the vertical stabilizer, the shoulder of force is the largest there (here you can again resort to the ruler and two fingers of different hands, the closer the rear finger is to the front one, the more effort is needed on it), because its can be made smaller and not as powerful as with the classical scheme. However, now all the loads directed along the pitch axis are not transferred to the fuselage, but to the vertical stabilizer, due to which it needs to be seriously strengthened and, therefore, weighted.

In addition, more and more pull the pipelines of the hydraulic control system, which further adds weight. And in general, this design is more complex, and therefore less secure. As for the fighters, why they use fully deflected planes and paired vertical stabilizers, the main reason is the increase in efficiency. After all, it is clear that there can be no extra maneuverability from a fighter.

Good detailed description. The tail unit of the aircraft really has a big effect on his manevrinost and stability in space. It is believed that no one flying machine can not do without it. Except diskoletov which have a number of disadvantages and therefore not developed nevypuskayutsya.

However, the plane classic aerodynamic scheme often can do without TO. Even the horizontal arrangement of GO (not V-shaped). Another thing is that such a scheme is not accepted, as in helping in crosswinds and low-speed flight. It is, by the way.

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