In the early thirties, Soviet specialists began to work out the appearance of promising self-propelled artillery installations. Various options for such a technique have been proposed, considered and tested, and some of them, having confirmed their potential, have found application in practice. Others were considered unsuccessful and were discarded. One of the examples of an interesting, but unpromising development in the field of self-propelled artillery can be considered a coastal self-propelled gun project, developed at the suggestion of A. A. Tolochkova.
One of the urgent problems of that time was the organization of antiamphibious defense on the numerous sea coasts of the Soviet Union. In 1932, the Artillery Research Institute proposed a new concept for the construction of coastal defense. According to it, for effective counteraction to enemy ships and amphibious assault landing vehicles, sufficiently powerful guns on self-propelled platforms were required. In the event of a threat of attack, they could promptly advance to coastal positions, meet the enemy with powerful fire and prevent him from even approaching the coastline.
Already at the end of 1932, the Red Army formed the requirements for a promising self-propelled gun for coastal defense. A few months later, experts reviewed proposals from a number of leading enterprises in the defense industry. The most successful was the proposal of the experimental design engineering department (OKMO) of plant No. 174 named after. Voroshilov. The project, developed under the leadership of Alexei Alexandrovich Tolochkov and Pyotr Nikolaevich Syachintov, needed some improvements, but was still of interest to the army.
The scheme of the coastal ACS A. A. Tolochkova in the stowed position
As far as is known, the promising project never received its own name. In all documents and sources, the self-propelled gun is referred to as a coastal self-propelled gun designed by A. A. Tolochkova or in some other similar way. The development organization is usually not mentioned in such names. It is noteworthy that in the latter case, there could be some confusion. The fact is that in September 1933, the OKMO of plant No. 174 was removed from the latter and became the Experimental Plant of Spetsmashtrest. The development of self-propelled guns for coastal defense began even before such transformations, and ended a few months after them.
The first OKMO project, proposed at the beginning of 1933, generally satisfied the customer, but he presented an additional requirement. The ACS was supposed to be based on the chassis of one of the serial medium or heavy tanks, or have the maximum degree of unification with the serial equipment. The most convenient source of aggregates was considered the newest T-28 tank. They decided to borrow from him the power plant, chassis elements, etc.
It took a lot of time to rework the existing project using the T-28 units. The Spetsmashtrest experimental plant was able to present a new version of Tolochkov's self-propelled guns only in March of the following 1934. The improved project retained the basic ideas proposed earlier. At the same time, it was revised taking into account the wishes of the customer and the availability of the units. In the updated form, the self-propelled gun corresponded to the technical specifications of the army and could count on mass production, acceptance into service and further operation.
As conceived by the designers Tolochkov and Syachintov, the new self-propelled gun was supposed to be an armored vehicle, literally built around a 152-mm long-range cannon. The ACS was proposed to be equipped with a high cross-country tracked chassis based on the units of a serial tank. At the same time, the selected gun was distinguished by excessive recoil power, and therefore, in the design of the self-propelled gun, it was necessary to provide special means for deployment in position. It was proposed to shoot not from the tracks, but from a special base plate.
The project provided for the construction of an armored corps with differentiated protection. Frontal and side projections were to be covered with 20-mm sheets. The roof, bottom and stern could be made of sheets with a thickness of 8 mm. The corps had to have a special shape, due to the need to accommodate a large and heavy artillery installation. Its front part was smaller and had to include elements of the power plant and transmission. All other volumes were a large fighting compartment, which housed a gun carriage.
According to the surviving diagrams, the frontal part of the hull was supposed to receive a semicircular lower part, above which an inclined upper sheet was placed. At the level of the front engine compartment, the height of the vertical sides increased sharply, which ensured the formation of the fighting compartment. The hull feed could have a simple shape. An interesting feature of the new self-propelled guns was a large window in the bottom, which was necessary for the withdrawal of the support devices of the artillery mount.
The engine of the T-28 tank was considered insufficiently powerful, and therefore the Tolochkova self-propelled gun was supposed to receive a BD-1 engine of Kharkov design. 800 hp motor placed in front of the body, directly behind the transmission. The front compartment was supposed to contain the main dry friction clutch, a five-speed gearbox, multi-disc dry side clutches and two-row final drives with band brakes. The transmission was completely borrowed from the production tank, but it was modified for installation in the front of the hull.
The self-propelled gun was supposed to receive an original chassis based on the details of the T-28. On each side, it was proposed to install 12 paired interlocked road wheels of small diameter. Each pair of rollers had its own shock absorber based on a vertical spring. In the front of the car there were drive wheels, in the stern - guides. It also provided for the use of six supporting rollers on each side.
The shock absorber bodies, wheels and rollers had to be secured to a strong longitudinal beam of great length. In its front part, it was planned to install an additional roller, and the stern parts of the two beams were connected to each other, forming a "tail". With the help of hydraulic drives, the beams could move up and down, which made it possible to hang the machine on the base plate of the gun mount. In the combat position, the tracks had to rise to the level of the hull and not touch the ground. According to calculations, it took only 2-3 minutes to transfer to a combat position.
Self-propelled gun in firing position: base plate lowered to the ground, undercarriage raised, gun at zero elevation
Most of the corps, according to the design of Tolochkov and Syachintov, was occupied by an artillery installation. A base plate with a roller shoulder was placed under the bottom of the hull, on which the rotating part of the gun carriage rested. The latter was connected to the body and could rotate with it in a horizontal plane. A massive gun carriage housed a gun with recoil devices, sighting devices and ramming devices.
As a gun for the coastal self-propelled gun was chosen long-range gun B-10 caliber 152, 4 mm, developed by the plant "Bolshevik". This gun had a 47-caliber barrel with a constant groove steepness. A manual piston valve was used. In the basic configuration, the B-10 cannon was mounted on a towed carriage with a caterpillar track. The latter provided horizontal guidance within 3 ° to the right and left and vertical guidance from -5 ° to + 55 °. In the firing position, the gun weighed 14, 15 tons. The calculation included 15 people.
The B-10 gun used 152-mm separate loading rounds with several types of shells. The muzzle velocity of the projectile, depending on its type, reached 940 m / s. The maximum firing range is about 30 km. The rate of fire was within 1-2 rounds per minute.
In the OKMO project of plant No. 174 / Experimental plant of Spetsmashtrest, the body of such a gun had to be mounted on a new carriage inside the hull. With the help of the base plate and the corresponding drives, circular guidance was provided horizontally. However, a full revolution around the axis should have taken about 20 minutes. The elevation angles have hardly changed compared to the towed gun carriage. The new installation received hydraulic drives. It was also possible to install electric drives. Probably, reserve manual mechanisms could be used.
It should be recalled that the B-10 cannon had a serious drawback in the form of a low rate of fire, due to the need to return the barrel to the ramming angle. In the new project, this problem was solved with the help of lifting mechanisms and an automatic rammer.
The designers managed to reduce the required number of gunners. The crew of the new self-propelled gun could consist of only 6-8 people - half that of a towed gun. Behind the engine compartment, inside the hull, there was a control post with a driver's seat. The rest of the crew in the stowed position were supposed to be in other places inside the car.
The new coastal defense ACS was supposed to be large and heavy. So, the total length, taking into account the side beams, could reach 12-13 m. The height in the stowed or combat position is at least 3-3.5 m. The combat weight, according to calculations, reached 50 tons. At the same time, a relatively powerful engine made it possible to obtain acceptable characteristics mobility. On the highway, Tolochkov's self-propelled gun could accelerate to 20-22 km / h.
A finished project of a self-propelled artillery mount with a B-10 gun for coastal defense was prepared at the end of 1934. This is where the well-known story of an interesting development ends. Any information about the project of A. A. Tolochkova and P. N. Syachintovs after 1934 are not found. Apparently, the customer got acquainted with the project and did not give permission to build a prototype. On the contrary, he could have ordered the closure of the project.
Experienced gun B-10 in the original towed configuration
No later than the mid-thirties, the Spetsmashtrest Experimental Plant stopped work on the topic of special self-propelled guns for anti-amphibious defense. The exact reasons for this are unknown, but you can try to make some assumptions. The known information, as well as the experience accumulated over the following decades, make it possible to imagine why the Tolochkov's self-propelled guns did not have real prospects, and could also become a big problem for the Red Army.
First of all, it is necessary to note the excessive complexity of the proposed project. For its time, the unusual self-propelled gun was too difficult to manufacture and operate. First of all, problems should have arisen with the carriage of an unusual design and the systems for moving the chassis. At the same time, it is not difficult to imagine what a breakdown or combat damage to the latter could lead to.
The failure of the B-10 gun could have been a serious blow to the ACS project. This product showed very high fire characteristics, but was distinguished by its large dimensions and weight, and in addition, it could not show a high rate of fire. This problem could be solved with the help of additional mechanized guidance controls or ramming. However, even after the modifications, the gun was not accepted into service, which could hit the prospects of a self-propelled vehicle for it.
Also, do not forget about the factor of competition. In the mid-thirties, Soviet designers proposed and implemented various options for the appearance of a self-propelled artillery installation, including with a large-caliber gun. Against the background of some other projects of its time, the ACS of the Spetsmashtrest Experimental Plant might not look the most successful.
One way or another, no later than the beginning of 1935, the developer of the project or a potential customer in the person of the Red Army decided to stop work. An interesting self-propelled gun for coastal defense remained on paper. The prototype was not built and probably was not even planned for construction.
The project of the ACS of coastal defense from A. A. Tolochkova and P. N. Syachintov was not implemented, but made a feasible contribution to the further development of domestic self-propelled artillery. He allowed to work out some design solutions and determine their prospects. In addition, the groundwork was created for the development of new chassis based on existing tanks. It is curious that the B-10 cannon, which also did not enter service, also influenced the development of artillery. Later, several new weapons were developed on its basis.
