The location of the tail on the airplane. Horizontal tail type Aircraft tail type

The tail is the airfoils located at the rear of the aircraft. They look like rather small “wings”, which are traditionally installed in horizontal and vertical planes and are called “stabilizers”.

It is precisely according to this parameter that the tail unit is divided, first of all, into horizontal and vertical, respectively, with the planes in which it is installed. A good design is one vertical and two horizontal stabilizers, which are directly connected to the rear fuselage. This is precisely the scheme that is most widely used on civil aircraft.

But there are other schemes - for example, the T-shaped one, which is used on the Tu-154.

In a similar design, the horizontal tail is attached to the top of the vertical tail, and when viewed from the front or rear of the aircraft, it resembles the letter “T”, hence its name. In addition, there is a scheme with two vertical stabilizers, which are placed at the ends of the horizontal tail; an example of an aircraft with this type of tail is the An-225. In addition, most modern fighters have two vertical stabilizers, but they are installed on the fuselage because they have a fuselage shape that is more “flattened” horizontally when compared with civil and cargo aircraft.

Well, in general, there are dozens of different tail configurations, and each one has its own disadvantages and advantages, which will be discussed a little lower. In addition, it is not always installed in the tail of the aircraft, but this only applies to horizontal stabilizers.

The tail of the Tu-154 aircraft

The tail of the An-225 aircraft

The principle of operation of the tail unit. Main functions.

And now about the functions of the tail, what is it for? Because it is also called stabilizers, it is possible to make the assumption that they stabilize something. That's right, that's true.

The tail is needed to balance and stabilize the aircraft in the air, and in addition to control the aircraft along two axes - yaw (left-right) and pitch (up-down).

Vertical tail unit.

The functions of the vertical tail are to stabilize the aircraft. In addition to the two axes listed above, there is also a third - roll (rotation around the longitudinal axis of the aircraft), and so, in the absence of a vertical stabilizer, the roll leads to the aircraft swaying on a fairly vertical axis, moreover, the swaying is very important and completely uncontrollable. The second function is yaw axis control.

A deflectable profile is attached to the trailing edge of the vertical stabilizer, which is controlled from the cockpit. These are the two main functions of the vertical tail, the number, shape and position of the vertical stabilizers are completely irrelevant - they perform these two functions invariably.

Types of vertical tail units.

Horizontal tail unit.

Now about the horizontal tail unit. It also has two main functions, the first one can be described as balancing. In order to find out what's what, you can perform a simple experiment.

You need to pick up some long object, for example a ruler, and place it on one outstretched finger so that it does not fall or tilt either back or forward, i.e. find its center of gravity. So, now the ruler (fuselage) has a wing (finger), balancing it like this is not difficult. Well, now you need to imagine that tons of fuel are being pumped into the train, many passengers are boarding, and a huge amount of cargo is being loaded.

Of course, loading all this perfectly relative to the center of gravity is easily impossible, but there is a way out. You need to use the finger of your second hand and place it on top of the conventionally rear part of the ruler, after which you move the “front” finger to the back one. The end result was a fairly stable structure.

It is also possible to do it differently: place the “back” finger under the ruler and move the “front” finger forward, towards the bow. Both of these examples show the principle of operation of a horizontal tail.

It is the first type that is more common, while horizontal stabilizers create a force opposite to the lift of the wings. Well, their second function is control along the pitch axis. Everything here is complete except for the same as with the vertical tail. There is a deflectable trailing edge of the profile, which is controlled from the cockpit and increases or decreases the force generated by the horizontal stabilizer due to its own airfoil.

Here it is necessary to make a reservation about the deflectable trailing edge, since some aircraft, especially combat aircraft, have entirely deflectable planes, and not just parts of them, this also applies to the vertical tail, but the functions and principle of operation do not change from this.

Types of horizontal tail units.

And now about why designers move away from a good design. At the moment, aircraft have a huge purpose and their number, along with the devils, is very different. And, in fact, here you need to analyze a specific class of aircraft, as well as a specific aircraft individually, but to find out the key principles, a few examples will suffice.

The first - the already mentioned An-225, has a double vertical tail for the reason that it can carry such a voluminous thing as the Buran shuttle, which in flight would obscure the only vertical stabilizer located in the center in the aerodynamic design, and its effectiveness was would be very low. The T-shaped tail of the Tu-154 also has its own advantages.

Because it is also located behind the rear point of the fuselage, due to the sweep of the vertical stabilizer, the shoulder of force in that place is the most enormous (here it is possible to again resort to a ruler and two fingers of different hands; the closer the rear finger is to the front, the greater the strengthening on it necessary), because it can be made smaller and not as remarkable as with a good scheme. But now all the loads directed along the pitch axis are transferred not to the fuselage, but to the vertical stabilizer, which is why it needs to be strengthened and made heavier accordingly.

In addition, you also have to additionally drag the pipelines of the hydraulic control system, which adds even more weight. And in general, this design is more complex and, accordingly, less reliable. As for fighters, why they use fully deflectable twin and plane vertical stabilizers, the main reason is to increase efficiency.

Since it is clear that the fighter does not have the ability to have excess maneuverability.

Landing with a destroyed tail

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AIRPLANE ELENATURE

Feathers (tail of an aircraft, rockets) are aerodynamic surfaces that provide stability, controllability and balancing of the aircraft in flight. It consists of horizontal and vertical tails.

Basic requirements for plumage:

Ensuring high efficiency with minimal drag and minimal weight of the structure;

There may be less shading of the empennage by other parts of the aircraft - the wing, fuselage, engine nacelles, as well as one part of the empennage by another;

Absence of vibrations and oscillations such as flutter and buffeting;

Later than on the wing, the development of the wave crisis.

Horizontal tail (HO)

Provides longitudinal stability, controllability and balancing. The horizontal tail consists of a fixed surface - a stabilizer and an elevator hinged to it. For tail-mounted aircraft, the horizontal empennage is installed at the rear of the aircraft - on the fuselage or on the top of the fin (T-shape).

In the canard design, the empennage is located in the nose of the aircraft in front of the wing. A combined scheme is possible, when an aircraft with a tail unit is equipped with an additional front empennage - a scheme with a front horizontal tail unit (front horizontal tail), which allows you to take advantage of both of these schemes. The “tailless” and “flying wing” designs do not have horizontal tail surfaces.

A fixed stabilizer usually has a fixed installation angle relative to the longitudinal axis of the aircraft. Sometimes provision is made for adjusting this angle on the ground. Such a stabilizer is called adjustable.

On heavy aircraft, to increase the efficiency of longitudinal control, the angle of installation of the stabilizer with the help of an additional drive can be changed in flight, usually during takeoff and landing, as well as to balance the aircraft at a given flight mode. Such a stabilizer is called movable.

At supersonic flight speeds, the effectiveness of the elevator drops sharply. Therefore, in supersonic aircraft, instead of the classic GO scheme with an elevator, a controlled stabilizer (CPGO) is used, the installation angle of which is adjusted by the pilot using the longitudinal control command lever or the aircraft’s on-board computer. In this case there is no elevator.

Vertical tail (VO)

Provides the aircraft with directional stability, controllability and balancing relative to the vertical axis. It consists of a fixed surface - the keel and a rudder hinged to it.

All-moving VO is used very rarely. The efficiency of the air defense can be increased by installing a forkeel - a forward influx in the root part of the fin and an additional ventral ridge. Another way is to use several (usually no more than two identical) keels.

Plumage forms

T-shaped tail of an aircraft (Tu-154)

The shapes of the tail surfaces are determined by the same parameters as the shapes of the wing: aspect ratio, taper, sweep angle, airfoil and its relative thickness. As in the case of the wing, trapezoidal, oval, swept and triangular tails are distinguished.

The plumage pattern is determined by the number of its surfaces and their relative position. The most common schemes are:

A scheme with a central location of the vertical tail in the plane of symmetry of the aircraft - the horizontal tail in this case can be located both on the fuselage and on the fin at any distance from the aircraft axis (a scheme with the GO located at the end of the fin is usually called a T-shaped tail).

Example: Tu-154

A design with a spaced vertical tail - (often called H-shaped) its two surfaces can be attached to the sides of the fuselage or at the ends of the horizontal tail. In a two-beam fuselage design, the VO surfaces are installed at the ends of the fuselage beams. On canard, tailless, and flying wing aircraft, the spaced air defense is installed at the ends of the wing or in its middle part.

Example: Pe-2, Lockheed P-38 Lightning

V-shaped tail, consisting of two inclined surfaces that perform the functions of both horizontal and vertical tail. Due to the complexity of control and, as a consequence, low efficiency, such plumage is not widely used. (True, the use of computer flight systems has changed the situation for the better. The current control of the V-shaped tail in the latest aircraft equipped with it is taken over by the on-board computer - the pilot only needs to set the flight direction (left-right, up-down) with a standard control stick, and the computer will do everything that is needed for this).

Example: F-117

Oblique plumage (butterfly type, or Rudlitsky plumage)

Example: Me.262 HG III

Stabilizers and keels

They have a complete analogy with the wing, both in the composition and design of the main elements - spars, longitudinal walls, stringers, ribs, and in the type of power circuits. For stabilizers, spar, caisson and monoblock schemes are quite successfully used, and for fins the latter scheme is used less frequently, due to certain design difficulties in transferring bending moment from the keel to the fuselage. The contour junction of the keel power panels with the fuselage in this case requires the installation of a large number of power frames or the installation on the fuselage in the plane of the keel power panels of powerful vertical beams, supported by a smaller number of fuselage power frames.

For stabilizers, the transfer of bending moments to the fuselage can be avoided if the spars or load-bearing panels of its left and right surfaces are connected to each other along the shortest path in its central part. For a swept stabilizer, this requires breaking the axis of the longitudinal elements along the side of the fuselage and installing two reinforced side ribs. If the longitudinal elements of such a stabilizer without breaking the axes reach the plane of symmetry of the aircraft, then in addition to the onboard power ribs that transmit torque, another power rib will be required in the plane of symmetry of the aircraft.

Rudders and ailerons

Due to the complete identity of the design and power operation of the rudders and ailerons, in the future, for brevity, we will talk only about the rudders, although everything said will be fully applicable to the ailerons. The main power element of the steering wheel (and aileron, of course), which bends and absorbs almost all the shear force, is the spar, which rests on the hinged supports of the suspension units.

The main load on the rudders is aerodynamic, which occurs when balancing, maneuvering an aircraft or when flying in rough air. Taking this load, the steering spar acts as a continuous multi-support beam. The peculiarity of its operation is that the rudder supports are fixed on elastic structures, the deformation of which under load significantly affects the force work of the rudder spar.

The perception of steering torque is ensured by a closed contour of the skin, which is closed by the spar wall in the cutout areas for the mounting brackets. The maximum torque acts in the section of the control horn to which the control rod fits. The location of the hog (control rod) along the span of the steering wheel can significantly influence the deformation of the steering wheel during torsion.

Aerodynamic compensation of rudders

In flight, when the control surfaces are deflected, hinge moments arise, which are balanced by the efforts of the pilot on the command control levers. These forces depend on the size and angle of deflection of the steering wheel, as well as on the speed pressure. On modern aircraft, the control forces are too large, so it is necessary to provide special means in the design of the rudders to reduce the hinge moments and the control forces that balance them. For this purpose, aerodynamic compensation of the steering wheels is used, the essence of which is that part of the aerodynamic forces of the steering wheel create a moment relative to the axis of rotation, opposite to the main hinge moment.

The most common types of aerodynamic compensation are:

Horny - at the end of the steering wheel, part of its area in the form of a “horn” is located in front of the hinge axis, which ensures the creation of a moment of the opposite sign in relation to the main hinge;

Axial - part of the steering wheel area along its entire span is located in front of the hinge axis (the hinge axis moves backward), which reduces the hinge moment;

Internal - usually used on ailerons and consists of plates attached to the nose of the aileron at the front, which are connected by a flexible partition to the walls of the chamber inside the wing. When the aileron deflects, a pressure difference is created in the chamber above and below the plates, which reduces the hinge moment.

Servo compensation - a small surface is hinged in the tail part of the rudder, which is connected by a rod to a fixed point on the wing or tail. This rod ensures automatic deflection of the servo compensator in the direction opposite to the steering deflection. Aerodynamic forces on the servo compensator reduce the steering joint moment.

The angles of deflection and the efficiency of such a compensator are proportional to the angles of deflection of the steering wheel, which does not always pay off, because control forces depend not only on the steering angles, but also on the speed pressure. More advanced is the spring servo compensator, in which, due to the inclusion of springs with pre-tensioning in the control kinematics, the deflection angles are proportional to the steering control forces, which best suits the purpose of the servo compensator - to reduce these forces.

Means of aerodynamic balancing of an aircraft

Any steady state of aircraft flight, as a rule, is carried out with the rudders deflected, which ensures balancing - balancing - of the aircraft relative to its center of mass. The resulting forces on the controls in the cockpit are usually called balancing. In order not to tire the pilot in vain and save him from these unnecessary efforts, a trimmer is installed on each control surface, allowing the balancing forces to be completely removed.

The trimmer is structurally completely identical to the servo compensator and is also hingedly suspended in the rear part of the steering wheel, but, unlike the servo compensator, it has additional manual or electromechanical control. The pilot, deflecting the trimmer in the direction opposite to the rudder deflection, achieves balancing of the rudder at a given deflection angle with zero effort on the command lever. In some cases, a combined trimmer-servo compensator surface is used, which, when the drive is turned on, works as a trimmer, and when turned off, it performs the functions of a servo compensator.

It should be added that the trimmer can only be used in control systems in which the forces on the command levers are directly related to the hinge moment of the steering wheel - mechanical boosterless control systems or systems with reversible boosters. In systems with irreversible boosters - hydraulic boosters - the natural forces on the control edges are very small, and to simulate “mechanical control” for the pilot, they are additionally created by spring loading mechanisms and do not depend on the hinge moment of the steering wheel. In this case, trimmers are not installed on the steering wheels, and the balancing forces are removed by special devices - trimming effect mechanisms installed in the control wiring.

Another means of balancing an aircraft in steady flight mode can be an adjustable stabilizer. Typically, such a stabilizer is hinged on the rear suspension units, and the front units are connected to a power drive, which, by moving the nose of the stabilizer up or down, changes its installation angles in flight. By selecting the desired installation angle, the pilot can balance the aircraft with zero hinge moment on the elevator. The same stabilizer also provides the required efficiency of longitudinal control of the aircraft during takeoff and landing.

Means for eliminating flutter of rudders and ailerons

The reason for the occurrence of flexural-aileron and flexural-steering flutter is their mass imbalance relative to the hinge axis. Typically, the center of mass of steering surfaces is located behind the axis of rotation. As a result, during flexural vibrations of the bearing surfaces, the inertial forces applied at the center of mass of the rudders, due to deformations and backlashes in the control wiring, deflect the rudders by a certain angle, which leads to the appearance of additional aerodynamic forces that increase the flexural deformations of the bearing surfaces. As the speed increases, the rocking forces increase and at a speed called the critical flutter speed, the structure collapses.

A radical means of eliminating this type of flutter is to install balancing weights in the nose of the rudders and ailerons in order to move their center of mass forward.

100% weight balancing of the steering wheels, in which the center of mass is located on the axis of rotation of the steering wheel, ensures complete elimination of the cause of the occurrence and development of flutter.

Selection and calculation

Deep stalls in aircraft with T-tails.

The tail organs in flight are subject to distributed aerodynamic forces, the magnitude and distribution law of which are specified by strength standards or determined by blowing. Due to their smallness, the mass inertial forces of the tail are usually neglected. Considering the work of the tail elements when perceiving external loads, by analogy with the wing, one should distinguish between the general force work of the tail units as beams, in the sections of which shear forces, bending and torques act, and the local work from the air load falling on each section of the skin with its reinforcements elements.

Various tail units differ from each other in purpose and methods of fastening, which introduces its own characteristics into power work and affects the choice of their structural power schemes. The required efficiency of the tail is ensured by the correct choice of the shape and location of its surfaces, as well as the numerical values of the parameters of these surfaces. To avoid shading, the tail organs should not fall into the wake of the wing, nacelles and other aircraft components. The use of computer flight systems has no less influence on the efficiency of the tail. For example, before the advent of fairly advanced aircraft on-board computers, the V-shaped tail was almost never used, due to its complexity in control.

The later onset of the wave crisis on the tail is achieved by increased sweep angles and smaller relative thicknesses compared to the wing. Flutter and buffeting can be avoided by known measures to eliminate these aeroelastic phenomena.

Empennage design

The tail of an aircraft is similar to a wing in its external shape, nature of loading and operation. Therefore, it consists of the same structural elements as the wing.

The power circuit of the stabilizer and keel consists of a longitudinal set (spars, walls and stringers), a transverse set (ribs) and skin. Like the wings, the stabilizer and fin can be spar or monoblock (caisson). At low and medium flight speeds with small elongations of the stabilizer and fin, the spar design turns out to be more advantageous.

The design of the keel compared to the stabilizer does not have any special differences. On small supersonic aircraft with a large sweep of the fin, a spar design with an internal strut is used.

On large aircraft, stabilizers and fins are usually monoblock with two or three spars.

Tail

Tail - airfoils located at the rear of the aircraft. They look like relatively small “wings”, which are traditionally installed in the horizontal and vertical planes and are called “stabilizers.” XO is designed to give stability and controllability to the aircraft. X. O. consists of a stabilizer, elevators, keel and rudder.

It is according to this parameter that the tail unit is divided, first of all, into horizontal and vertical, respectively, with the planes in which it is installed. The classic design is one vertical and two horizontal stabilizers, which are directly connected to the rear fuselage. This is the scheme most widely used on civil airliners. However, there are other schemes - for example, T-shaped, which is used on the Tu-154.

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

Well, in general, there are dozens of different tail configurations and each has its own advantages and disadvantages, which will be discussed below. It is not always installed in the tail of the aircraft, but this only applies to horizontal stabilizers

The tail of the Tu-15 aircraft

The principle of operation of the tail unit. Main functions

And now about the functions of the tail, why is it necessary? Since it is also called stabilizers, we can assume that they stabilize something. That's right, that's true. The tail is necessary to stabilize and balance the aircraft in the air, and also to control the aircraft along two axes - yaw (left-right) and pitch (up-down).

Vertical tail

tail tail keel

The functions of the vertical tail are to stabilize the aircraft. In addition to the two axes listed above, there is also a third - roll (rotation around the longitudinal axis of the aircraft), and so, in the absence of a vertical stabilizer, the roll causes the aircraft to sway relative to the vertical axis, moreover, the sway is very serious and completely uncontrollable. The second function is yaw axis control.

A deflectable profile is attached to the trailing edge of the vertical stabilizer, which is controlled from the cockpit. These are the two main functions of the vertical tail, the number, position and shape of the vertical stabilizers are absolutely unimportant - they always perform these two functions

Types of vertical tail units

Horizontal tail

Now about the horizontal tail unit. It also has two main functions, the first can be described as balancing. In order to understand what's what, you can conduct a simple experiment. It is necessary to take a long object, for example a ruler, and place it on one outstretched finger so that it does not fall or bend either back or forward, i.e. find its center of gravity. So, now the ruler (fuselage) has a wing (finger), it doesn’t seem difficult to balance it. Well, now you need to imagine that tons of fuel are being pumped into the train, hundreds of passengers are boarding, and a huge amount of cargo is being loaded.

Naturally, it is simply impossible to load all this perfectly relative to the center of gravity, but there is a way out. It is necessary to resort to using the finger of the second hand and place it on top of the conditionally rear part of the ruler, and then move the “front” finger to the back. The result is a relatively stable structure. You can also do it differently: place the “back” finger under the ruler and move the “front” finger forward, towards the bow. Both of these examples show the principle of operation of a horizontal tail.

The first type is more common, when horizontal stabilizers create a force opposite to the lifting force of the wings. Well, their second function is control along the pitch axis. Here everything is absolutely the same as with the vertical tail. There is a deflectable trailing edge profile, which is controlled from the cockpit and increases or decreases the force that the horizontal stabilizer creates due to its aerodynamic profile. Here a reservation should be made regarding the deflectable trailing edge, because some aircraft, especially combat aircraft, have completely deflectable planes, and not just parts of them, this also applies to the vertical tail, but the principle of operation and functions do not change.

Types of horizontal tail units

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

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

In addition, you also have to additionally pull the pipelines of the hydraulic control system, which adds even more weight. And in general, this design is more complex, and therefore less safe. As for fighters, why they use fully deflectable planes and twin vertical stabilizers, the main reason is to increase efficiency. After all, it is clear that a fighter cannot have excess maneuverability

The T-shaped tail of the aircraft contains a keel, on the top of which is mounted a rotary stabilizer, equipped with a drive and hinged attachment units consisting of a pair of forks, each of which includes external and internal eyes on the stabilizer spar and a fin eye, in the holes of which there are bearings The connecting device has been installed. Each of the keel eyes consists of two parts and a cup with a ball bearing is installed in it. Each outer and inner eye of the stabilizer fork is connected to the keel eyes with a hollow bolt, inside of which there is a duplicate bolt, tightened with a nut, on top of which a nut with a stopper is installed to fix the position of the keel eyes relative to the fork. The ends of the mentioned hollow bolts are located between the forks with an end gap and are connected to each other by an intermediate sleeve enclosing them, on the outer side of which there is a stabilizer steering control rocker, secured with a locking ring with a bolt. The invention is aimed at increasing the survivability of the aircraft. 6 ill.

There are known aircraft with a T-shaped tail, in which the rotary stabilizer is mounted on rear hinge joints with a common axis of rotation, consisting of lugs, forks and bolts connecting them, and having a front hinge joint connected to the aircraft frame by the stabilizer control mechanism (see Manual for the operation of the TU-154M aircraft, section 055.50.00, page 3/4, Fig. 1, February 22/85).

However, the known device has a number of disadvantages.

There is no duplication of vital elements, i.e. those elements whose destruction leads to an aircraft crash. Such elements are the rear hinge joints for installing the rotary stabilizer on the fin of the aircraft. Flight safety is ensured due to very low design stresses in the elements of the hinge joints, which leads to additional weight of the structure, since it is necessary to increase the dimensions (thickness) of the lugs, the dimensions of the fairings covering these lugs, and hence an increase in aerodynamic drag.

The objective of the present invention is to increase the survivability of the aircraft by increasing the reliability of the T-tail design.

The solution to the technical problem is ensured by the fact that the design of the movable mount of the stabilizer on the keel has duplicate vital elements.

The tail of the aircraft has a rotary stabilizer 1, mounted on the fin 2 on two hinged attachment points with a connecting device, each of which consists of a fork (see Fig. 2) containing an external eye 3 and an internal eye 4, which are made on the stabilizer spar 5 1, and eyes 6 of the keel 2. In the eye 6 there is a glass 7, secured with a nut 8, in which a ball bearing 9 is located, secured with a nut 10. Eyes 3,4 of the fork are connected to eye 6 with a bolt 11, inside of which there is a duplicate bolt 12, tightened nut 13. The package of parts 9.14 is tightened through bolt 11 with nut 15, which has an external left-hand thread. A nut 16 is screwed onto the nut 15, which fixes the position of the eye 6 relative to the keel fork. Nut 16 is locked with washer 17. The ends of bolts 11 are connected by bushing 18 to a bronze liner. On the sleeve 18, on the outer side, there is a rocker 19 for controlling the stabilizer rudders, which is fixed on it with a ring 20 through a bolt 21, which simultaneously connects the sleeve 18 with bolt 11.

The work is carried out as follows.

In case of destruction of the bolt 11 in the connecting device, the load is taken by bolt 12. The eye 6 of the keel 2 consists of two parts of equal thickness and, in the event of destruction of one of the halves, the load is taken by the second half of the eye.

When one of the four eyes 3,4 of the stabilizer forks is destroyed, the aerodynamic load from it is transferred to the eyes 6 of the keel 2 through the bending of hollow bolts 11, connected to each other by a sleeve 18, which takes the bending moment and shearing force at the junction of the bolts. When the outer eye 3 of the stabilizer fork is destroyed, the hollow bolts 11 with the bushing 18 act as a cantilever beam supported on the adjacent hinge joint and the inner eye 4 of the fork. When the inner eye 4 is destroyed, the bolts with the sleeve 18 act as a two-support beam resting on the outer eye 3 of the stabilizer fork and the adjacent hinge joint.

The use of the invention will improve reliability and reduce accidents and catastrophes by increasing the flight safety of aircraft with a T-tail due to duplication of vital design elements for attaching the stabilizer to the fin.

Claim

The tail of an aircraft, containing a fin, on the top of which is mounted a rotary stabilizer, equipped with hinged fastening units with a connecting device on bearings, consisting of a pair of forks, each of which includes external and internal eyes on the stabilizer spar and a fin eye, characterized in that that the connecting device is installed in both stabilizer forks and keel eyes, each of the keel eyes consists of two parts and a cup with a ball bearing is installed in it, and each outer and inner stabilizer fork eyes are connected to the keel eyes with a hollow bolt, inside of which a duplicate a bolt tightened with a nut, on top of which a nut with a stopper is installed to fix the position of the keel eyes relative to the fork, while the ends of the said hollow bolts are located between the forks with an end gap and are connected to each other by an intermediate sleeve covering them, on the outer side of which a stabilizer steering wheel control rocker is installed, secured with a locking ring and bolt.

The design of the tail unit depends significantly on the overall design of the aircraft. Due to the placement, the efficiency of the empennage is influenced by the wing and propeller. The installation of the empennage on the fuselage or tail booms also determines the structural layout of the fuselage (beams) in this place.

Examples of tailplanes, borrowed from practice, are shown in Figure 4. Other tailplane options are also possible, which are not discussed here (for example, a V-shaped tailplane).

Basic plumage schemes

The most common is a scheme with one fin and a stabilizer mounted on the fuselage or fin - (Fig. 4 a, b, c). It provides structural simplicity and rigidity, although in the case of the T-tail (Fig 4c) it is necessary to take measures to prevent its flutter.

The T-shaped tail design also has a number of advantages. The location of the horizontal tail in the upper part of the keel creates an endplate effect for the latter, which can help reduce the required area of the vertical tail. On the other hand, the high-mounted horizontal tail is located in the zone of a slight bevel of the flow from the wing at medium (flight) angles of attack, which makes it possible to reduce the required area of the horizontal tail. Thus, the area of the T-tail can be smaller than the area of the tail with a low horizontal tail.

The required vertical tail area is largely determined by the length and area of the lateral projection of the part of the fuselage located in front of the aircraft's center of gravity. The longer the forward part of the fuselage (and the larger the area of its lateral projection), the greater, other things being equal, is the area of the vertical tail necessary to eliminate the destabilizing moment of this part of the fuselage.

If the engines are located on the wing, then flight with one engine failed is a condition for sizing the fin and rudder of a multi-engine aircraft.

A significant height of the vertical tail (if its required area) can lead to the appearance of roll moments when the rudder is deflected as a result of a large shoulder between the center of pressure of the vertical tail and the longitudinal axis of the aircraft. If such a danger exists, the spaced twin-fin tail design, which reduces this effect, deserves attention (Fig. 4e). For a two-beam (Fig. 4d) or frame aircraft design, the choice of such an empennage is obvious. Since the placement of the fins at the ends of the horizontal tail creates the effect of end washers, the area of the horizontal tail can be reduced.

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Russian fighter "SU-30 SM" 1/72 (7314) , . The Su-30 SM is a two-seat multi-role heavy fighter developed by the Sukhoi Design Bureau. The fighter made its first flight in 2012. The Su-30 SM is designed both to gain dominance in...

The tail is the airfoils located at the rear of the aircraft. They look like relatively small “wings”, which are traditionally installed in horizontal and vertical planes and are called “stabilizers”.

The tail of the Tu-154 aircraft

The tail of the An-225 aircraft

The principle of operation of the tail unit. Main functions.

Vertical tail unit.

The functions of the vertical tail are to stabilize the aircraft. In addition to the two axes listed above, there is also a third - roll (rotation around the longitudinal axis of the aircraft), and so, in the absence of a vertical stabilizer, the roll causes the aircraft to sway relative to the vertical axis, moreover, the sway is very serious and completely uncontrollable. The second function is yaw axis control.

A deflectable profile is attached to the trailing edge of the vertical stabilizer, which is controlled from the cockpit. These are the two main functions of the vertical tail unit; the number, position and shape of the vertical stabilizers are absolutely unimportant - they always perform these two functions.

Types of vertical tail units.

Horizontal tail unit.

Types of horizontal tail units.

It might be useful to read:

The location of the tail on the airplane. Horizontal tail type Aircraft tail type

Horizontal tail unit.

Landing with a destroyed tail

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The principle of operation of the tail unit. Main functions.

Vertical tail unit.

Horizontal tail unit.