Military Review

"Tank stand with three-plane stabilization of the tower"

According to the old joke, the ballistic trajectory of the projectile allows the cannon to shoot around the corner, for which it must be laid on its side. However, in life such a shot will look different. The projectile will still fly forward and is unlikely to be able to hit the intended target. Even a small inclination of the gun in the direction will significantly change the trajectory of the projectile, and in the case of direct fire, it will require additional complex calculations and amendments in two planes at once. For this reason, the tankers for a long time tried to shoot, being on a flat surface and not allowing the roll of the combat vehicle. Solving the problem of aiming in difficult conditions was suggested in many different ways. However, until a certain time, all these methods remained only suggestions. Approximately at the end of the sixties, German tank builders began the implementation of a new original idea, designed to solve the existing problem with guarantee.

One of the German companies involved in the creation of armored vehicles (unfortunately, there are no direct references to specific authors of the project) put forward a new proposal for equipment and architecture tank. According to the authors of the proposal, the latest two-plane weapons stabilizers did not fully cope with their responsibilities. This equipment corrected the swing of the gun in the horizontal and vertical plane, but did not allow to control its rotation around its own axis. Such stabilization was required for reliable shooting at any longitudinal or transverse tilt of the tank. To form the appearance of such a three-plane stabilizer was not too difficult. But the integration of this system into the classic layout of the tank entailed substantial improvements in the design of both the turret and the chassis.

The project of the new tank was called Erprobungsträger mit 3-achs-stabilisiertem Turm (“Test stand with three-axis stabilization of the tower”). As the basis for a new armored vehicle, they took the chassis of the main tank Leopard 1. During the design work, the German engineers significantly changed a number of the most important chassis assemblies. So, a new 1000 engine of horsepower was installed on it (the Leopard’s own engine gave 830 total), changed the design of the engine compartment, increased the width of the car and modified the front of the hull. However, the middle part of the armored corps, in which the combat compartment was located on the original Leopard 1, underwent the greatest changes. From the former habitable volume, they removed all components and assemblies that could prevent the installation of a new tower of the original design. In addition, there were placed some mechanisms that ensure the mobility of the tower. It was probably a hydraulic system, but there is no exact data on this.

The most interesting part of a promising three-axis stabilization tank is its tower. Its upper part, located above the roof of the armored body, had the characteristic shape of a spherical layer. Below the roof of the hull the outlines of the tower were also round. This was done so that the tower could not only rotate around a vertical axis, but also bend around two horizontal: transverse and longitudinal. With the help of such a system, horizontal guidance was planned to be carried out by turning the entire tower, and the vertical one - by its inclination. The third axis of rotation was required to compensate for the rolls of the tank itself. Thus, regardless of the position of the tank in space (of course, at reasonable angles of the longitudinal and lateral inclination of the machine), the gun was always kept in the same position required for the shot.

"Tank stand with three-plane stabilization of the tower"

The stabilizer itself was made on the basis of the available models and had a gyroscope and a set of sensors with equipment for generating commands for the tower drives. The new stabilizer differed from the old two-plane stabilizers by the presence of additional sensors and another system of rotation and tilt of the tower.

Turned and tilted in all directions, the tower simplified the installation system of the gun. Presumably 105-mm rifled gun L7 mounted on recoil devices and stiffer suspension. The dimensions of the turret and the breech part of the gun, as well as the volume required to accommodate the crew, did not allow a large number of shells to be placed in the turret. A feeding niche with styling also could not solve the problem, since it significantly reduced the tool pointing angles. For this reason, as they say, with a reserve for the future, next to the main tool, they provided for a twin 30-mm automatic cannon. Due to the lack of space inside the turret, the cannon and the ammunition box were placed on a special bracket on the front sheet of the turret.

It is known about the construction of at least one prototype of the tank Erprobungsträger mit 3-achs-stabilisiertem Turm and its further testing. According to reports, driving performance remained at the level of the base Leopard 1. Regarding the fire capabilities of the machine with a three-plane stabilization, there is no accurate information. Most likely, the new weapon stabilization system could prove its advantages over the existing ones. However, even without official information, it can be assumed that stabilization in the third plane in most situations turned out to be superfluous, since not always the experienced tank had to fire from such difficult positions.

The result of the Erprobungsträger mit 3-achs-stabilisiertem Turm project was the collection of a large amount of information about the applied technical solution and the closure of all works. The advantages of the original stabilization system could not outweigh its inherent disadvantages. A whirlwind tower with a rigidly mounted gun was too difficult to manufacture and of little use for real use. The limited volume of the fighting compartment simply did not allow to place sufficient ammunition or another larger-caliber gun. An alternative to the swinging turret could be a special system for suspending the instrument, swinging in a vertical plane and turning the gun around its axis. However, this method of three-plane stabilization was not used on any experimental armored vehicle.

The only component of the original three-plane stabilizer that has been used in the future is the sensor system with the ability to measure the roll of the tank. As for the actual stabilization of the cannon in the third plane, on the new German tank Leopard 2, as well as on other similar machines of recent times, the tasks of roll compensation are assigned to a special algorithm for the operation of the fire control system. The body tilt sensors collect information about the position of the combat vehicle and transmit it to the computer. He forms the necessary amendments and gives the appropriate commands to the executive mechanisms of the weapons stabilizer, which turn the weapon in two planes. Thus, the original idea with a full-fledged three-plane stabilizer could not find a place in the equipment of modern tanks, but it helped solve the old problem with shooting accuracy.

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  1. Mikhado
    Mikhado 6 June 2013 08: 44
    Thanks for the interesting article, a really important issue for an accurate shot. Well, that really did not need to fence the 3rd axis of stabilization.
  2. stas52
    stas52 6 June 2013 09: 38
    ballistic curve, this is a change in the trajectory of the projectile, through gravity. Therefore, the position of the gun, on its side or upside down, does not affect accuracy, this is the effect of the position of the sight, i.e. if you stabilize the sight itself relative to the position of the barrel, the shot will be as accurate.
    1. ramsi
      ramsi 6 June 2013 10: 36
      rifling should have some effect, but now the guns are mostly smoothbore.
      1. cth; fyn
        cth; fyn 6 June 2013 17: 04
        Along the way, a couple of people have difficulties with a sense of humor ...
        1. Containers
          Containers 6 June 2013 23: 04
          Alas, I did not notice the "humor" tag. Oh, yes - he's not here.
      2. ramsi
        ramsi 7 June 2013 08: 30
        when rifled, the projectile flies strictly in a certain place to the orientation of the barrel (remember the AKM compensator, sighting with an attached bayonet of a mosin rifle ...)
        Another thing is to fence a garden with a swinging tower ... It would be better if we thought about turning the trunk, or at least the part that moves during the rollback
  3. Aleks tv
    Aleks tv 6 June 2013 16: 19
    It was interesting to read, thanks for the article Cyril.
    A three-plane stabilizer in a swinging tower is great, but only as a theory in the form that the Germans did, a stand - it is a stand.
    Fighting and servicing such vehicles in the field is unacceptable.

    You always feel the lack of a third plane (axial) in the stabilizer when shooting in motion, it is a boom to dream that they will come up with something. Or an improvement in the system, more accurately taking into account the inclination of the case.

    So the Germans planned to accommodate the crew. Special equipment is clearly visible:
  4. Jurkovs
    Jurkovs 6 June 2013 18: 32
    I thought that already on the T-64 the idea of ​​making amendments to the shooting by the computer system was realized. It is much easier than iron to fence.
  5. MiG-31
    MiG-31 6 June 2013 20: 11
    For some reason, I immediately remembered an American submachine gun that could shoot around the corner. About a month ago I saw an article on this subject.
  6. uzer 13
    uzer 13 6 June 2013 20: 50
    Stabilization along three rotation axes is a tempting, but technically difficult to implement, and quite financially expensive option. When driving on very rough terrain and in the absence of the ability to give the gunner a path, this stabilization mode is useful, but this is not always required when operating a combat vehicle. The design of the tank is also very complicated. It’s hardly worth the effort. If even the Germans did not continue to work in this direction, then this can be considered the opinion of experts on the inappropriateness of using such a device. A more suitable option would be to install gyroscopic sensors on the tank’s body, but on the gun - G-sensor capable of determining the acceleration vector. After processing by the computing device, you can obtain data for making corrections to the gun stabilizer.
  7. Containers
    Containers 6 June 2013 23: 01
    "Even a slight tilt of the gun to the side will significantly change the trajectory of the projectile, and in the case of direct fire, it will require additional complex calculations and corrections in two planes at once."

    Sorry, nonsense. Apparently, I don’t understand something in this thesis ...
    1. anomalocaris
      anomalocaris 8 June 2013 07: 14
      The author probably meant a change in the position of the optical axis of the sight and the axis of the barrel relative to the target. These things really significantly affect the accuracy of shooting, but here is how the rotation of the barrel around the axis affects the trajectory. even kill, I don’t understand.
      1. ramsi
        ramsi 8 June 2013 09: 51
        bending of the barrel occurs in a certain plane and if it turns the projectile, say, to the left, then when the barrel axis is rotated counterclockwise, the projectile will fly to the left and lower, and clockwise - to the left and higher
        1. anomalocaris
          anomalocaris 8 June 2013 09: 57
          Explain: what forces cause this bend? And in what "certain" plane?
          1. ramsi
            ramsi 8 June 2013 11: 48
            when the projectile moves through the rifles, there should be uneven pressure on the barrel wall, as a result of which the barrel bends (maximum in the middle part). In fact, it may even be some kind of irregular cone with a vertex at the beginning of the trunk and a base at the end of the trunk
            1. anomalocaris
              anomalocaris 8 June 2013 12: 20
              As a result of the movement of the projectile along the grooves, only torsional vibrations arise, which practically have no effect on the external ballistics. Oscillations of the trunk in some plane cause irregularities in the elastic deformations of its walls. In the absence of external forces (i.e., support reactions, gravity, reaction from the operation of the gas outlet unit), oscillations are equally probable in any plane passing through the axis of the bore. In reality, this "spherical trunk in a vacuum" does not exist, which determines the restrictions on the choice of possible directions of oscillations. But only. These oscillations have very little effect on the trajectory (the projectile, like any body, will fall to the center of the earth), they are one of the factors that determine the accuracy of fire of this particular sample.
              But the position of the plane passing through the optical axis of the sight and the axis of the barrel channel, relative to the horizon, has a very big influence on the accuracy of aiming in range.
              1. ramsi
                ramsi 8 June 2013 14: 22
                the bend of the trunk will be; and the longer the barrel, the more powerful the charge - the greater the bend. It is unlikely (at the same time) that oscillations cannot arise in all planes in any way - precisely along the pitch of the rifling. In the middle of the trunk, like any long stick, the weakest point is obtained. In a smoothbore, the picture should be similar to that described by you. Although just a crooked trunk, too, probably no one canceled
                1. anomalocaris
                  anomalocaris 8 June 2013 14: 34
                  Dear, it is equally probable and at the same time these are not synonyms.
                  The barrel to compare with a stick is extremely incorrect. This is a beam with a cantilever section and various support options. By the way, the most loaded point of the trunk is not necessarily its middle.
                  Yes, and please explain how exactly the grooving oscillations occur?
                  1. ramsi
                    ramsi 8 June 2013 16: 27
                    I know that there are no synonyms; in which plane the maximum bend occurs - it's hard to say - this plane rotates along with the movement of the projectile, but the effect is monotonous, to which you can adapt; And finally, the bending itself - I probably put it unsuccessfully: the torsional moment from the "weight and speed" of the projectile turns out to be so great that it overcomes the stiffness, weight and inertia of the barrel, forcing it to bend in time. In addition, by the middle of the barrel, the maximum pressure of the powder gases has already been reached. Unfortunately, I can't express myself more clearly, I studied poorly. Somewhere on the Internet there is a video in slow motion of a shot from the SVT, where the bend of the barrel is clearly visible
                    1. anomalocaris
                      anomalocaris 8 June 2013 16: 40
                      Torque occurs as a reaction to cutting a belt into rifling. it does not directly affect the lateral vibrations of the trunk. Its influence is indirect and related to the heterogeneity of the barrel material, which, in turn, causes the heterogeneity of the deformation.
                      Smokeless gunpowder develops maximum pressure at a distance of 1/4 to 1/2 of the length of the bore. Usually they pick up such a powder and charge that the maximum would be 1/3.
                      SVT has gas exhaust automation, a very long (about 78 calibers) and the most lightweight barrel. This example is not very good for comparison with a cannon barrel.
                      But that is not the point.
                      The essence is different - the rotation of the barrel does not have any effect on the trajectory of the projectile.
                      1. ramsi
                        ramsi 8 June 2013 17: 48
                        note, SVT is a rifle, not a cannon, besides, with an additional stiffness point (gas outlet) behind the middle of the barrel, the steepness of the rifling and so on - no comparison, and the effect is not frail, judging by the video. In addition, the "guys" took care of the problem - just like that, in your opinion, or because there is nothing to do? ..
                      2. anomalocaris
                        anomalocaris 8 June 2013 19: 02
                        Mdya ...
                        Gas vent at SVT, AKM, M-16, etc. NEVER is an increase in the rigidity of the barrel (there is no stiffening point), because it does not have a rigid connection with the receiver (and it cannot have for a number of reasons). On the contrary, the gas vent creates additional forces causing vibrations of the barrel.
                        Hm. And if it’s not a secret, what is the step of the rifling of the CBT and, for example, L7? And how does this affect barrel vibrations?
                        What problem arises when shooting in roll, I have repeatedly written above, and not only me. Bother to read.
                      3. ramsi
                        ramsi 8 June 2013 19: 21
                        Gas vent at SVT, AKM, M-16, etc. NEVER is an increase in the rigidity of the barrel (there is no stiffening point), because it does not have a rigid connection with the receiver (and it cannot have for a number of reasons). On the contrary, the gas vent creates additional forces causing vibrations of the barrel.
                        vibrations, but not bends ...
                        But by the way ... I have no more arguments, you can put another minus and celebrate the victory
                      4. anomalocaris
                        anomalocaris 8 June 2013 19: 30
                        Naturally. You cannot have arguments, for they are knowledge, but you are not burdened with it.
                        I’m not going to put a minus for you, because not why.
                        And victory ... But what victory, if a person for the entire duration of the dispute did not even bother to get into Wikipedia, not to mention reading a more or less serious study on this topic?
                      5. ramsi
                        ramsi 8 June 2013 20: 21
                        so there is no bending of the trunk ?!
                      6. anomalocaris
                        anomalocaris 9 June 2013 16: 35
                        Bending than?