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 building coastal defense. According to her, for effective countering the ships and the landing craft of the enemy required sufficiently powerful weapons on self-propelled platforms. In the event of a threat of attack, they could promptly advance to coastal positions, meet the enemy with powerful fire and not allow him to even get close to the coastline.
Already at the end of 1932, the Red Army formed the requirements for a promising SPG for coastal defense. A few months later, experts reviewed proposals from a number of leading defense enterprises. The most successful was the proposal of the Experimental Design Machine-Building Department (OKMO) of the plant No. XXUMX them. Voroshilov. The project, developed under the leadership of Alexei Alexandrovich Tolochkov and Pyotr Nikolayevich Syachintov, needed some improvements, but still was of interest to the army.
Scheme of coastal SAU A.A. Tolochkova in the traveling position
As far as we know, a promising project has not received its own name. In all documents and sources the self-propelled gun is referred to as coastal self-propelled guns of the AA design Tolochkova or otherwise. A 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 plant No. 174 was removed from the latter and became the Experimental Plant of Spetsmashrest. 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 in early 1933, generally satisfied the customer, but he submitted an additional requirement. Self-propelled guns should be based on the chassis of one of the serial medium or heavy tanks or have the maximum degree of unification with serial equipment. The most convenient source of units was considered the latest T-28 tank. They decided to borrow a power plant, elements of the chassis, etc.
It took a lot of time to rework an existing project using T-28 units. The Experimental Plant of Spetsmashtresta could present the new version of Tolochkova's ACS only in March of the next 1934 of the year. In the improved project, the main ideas proposed earlier were preserved. At the same time, it was reworked taking into account the wishes of the customer and the availability of the units. In an updated form, the self-propelled gun corresponded to the technical requirements of the army and could count on mass production, acceptance for 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 the 152-mm long-range gun. SAU was proposed to equip tracked chassis of high maneuverability, based on the units of the serial tank. In this case, the selected gun differed in excessive recoil power, and therefore in the design of the self-propelled gun had to provide special means for deployment to the position. It was suggested 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 8 mm thick sheets. The corps had to have a special shape, due to the need to deploy 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 in which the gun carriage with a weapon was placed.
According to the preserved diagrams, the frontal part of the body was to receive a semicircular lower part, above which the 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 a fighting compartment. The hull feed could have a simple shape. An interesting feature of the new ACS was a large window in the bottom, which is required for the withdrawal of the artillery support devices.
The engine of the T-28 tank was considered not powerful enough, and therefore the Tolochkova SAU should have received the engine of the BN-1 Kharkov design. Motor power 800 HP placed in front of the hull, directly behind the transmission. In the front compartment were supposed to be the main friction dry friction, five-speed gearbox, dry multi-disc side clutches and two-row side gears with band brakes. The transmission was fully borrowed from the serial tank, but was modified to be installed in front of the hull.
The ACS should have received an original undercarriage based on the details of the T-28. On each board it was proposed to install 12 in pairs of interlocked small-diameter road wheels. Each pair of rollers had its own shock absorber based on a vertical spring. In front of the car were driving wheels, in the stern - guides. Also provided for the use of six supporting rollers on each side.
The shock absorber bodies, wheels and rollers should be fixed on a strong longitudinal beam. In its front part, the installation of an additional skating rink was envisaged, 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 car on the support plate of the gun mount. In a 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 the combat position.
Self-propelled gun in the fighting position: the base plate is lowered to the ground, the chassis is raised, the gun is at zero elevation angle
Most of the corps, according to the project of Tolochkov and Syachintov, was occupied by an artillery installation. Under the bottom of the hull placed a base plate with a roller shoulder strap, on which was supported the rotating part of the mast. The latter was connected to the body and could rotate with it in the horizontal plane. On a massive carriage were placed gun with recoil devices, sighting devices and means of dismantling.
The long-range gun B-10 caliber 152,4 mm, developed by the Bolshevik plant, was chosen as a tool for coastal self-propelled guns. This gun had a barrel length 47 calibers with a constant slope of the rifling. Used piston valve with manual control. In the basic configuration, the B-10 cannon was mounted on a towed carriage with a tracked course. The latter provided horizontal guidance within 3 ° to the right and to the left and vertical from -5 ° to + 55 °. In combat, the gun weighed 14,15 t. The calculation included a 15 man.
The gun B-10 used 152-mm separate loading shots with projectiles of several types. The initial 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 shots per minute.
In the design of the OKMO plant No. XXUMX / Experimental Plant of Spetsmashtrest, the body of such an instrument was to be mounted on a new carriage inside the hull. With the help of the base plate and the corresponding drives provided a circular aiming horizontally. However, a full revolution around the axis should take about 174 minutes. The angles of the vertical pickup almost did not change in comparison with the towed carriage. New installation received hydraulic drives. It was also possible to install electric drives. Probably, reserve manual mechanisms could be applied.
It should be recalled that the gun B-10 had a serious drawback in the form of low rate of fire, due to the need to return the barrel to the angle of spreading. 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 ACS could consist of just 6-8 people - half the size of the towed gun. Behind the engine compartment inside the hull was a control post with a driver's seat. The rest of the crew in the stowed position had to be in other places inside the car.
The new ACS of the coastal defense was supposed to be large in size and mass. Thus, the total length, taking into account the side beams, could reach 12-13 m. Height in marching or combat position - no less than 3-3,5 m. Combat weight, according to calculations, reached 50 t. At the same time, a relatively powerful engine made it possible to obtain acceptable mobility characteristics. On the highway, the Tolochkova self-propelled gun could accelerate to 20-22 km / h.
The finished draft self-propelled artillery installation with a B-10 gun for coastal defense was prepared at the end of 1934. At this famous story curious development ends. Any information about the project A.A. Tolochkova and P.N. Syachintova after 1934 year not occur. 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.
Experimental gun B-10 in the original towed configuration
Not later than the mid-thirties, the Experimental Plant of Spetsmashtrest stopped work on the subject of a special self-propelled gun for anti-airborne defense. The exact reasons for this are unknown, but you can try to make some assumptions. Known information, as well as experience gained over the following decades, allows us to imagine why the Tolochkova’s self-propelled guns had no 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, an unusual self-propelled gun was too complicated to manufacture and operate. First of all, there should have been problems with the carriage of unusual design and systems for moving the chassis. In this case, it is not difficult to imagine what the damage or combat damage of the latter could lead to.
A serious blow to the project SAU could be the failure of the gun B-10. This product showed very high firing characteristics, but differed in large dimensions and weight, and besides, it could not show a high rate of fire. This problem could be solved with the help of additional mechanized controls for aiming or bilking. However, even after the modifications, the gun was not used for service, which could hit the prospects of a self-propelled machine for it.
Also do not forget about the factor of competition. In the mid-thirties, Soviet designers offered and implemented different versions of 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 Experimental Plant of Spetsmashrest could not look the most successful.
Anyway, no later than the beginning of 1935, the project developer or potential customer in the person of the Red Army decided to stop working. The most interesting self-propelled gun for coastal defense remained on paper. The prototype was not built and probably was not even planned for construction.
Project SAU coastal defense from A.A. Tolochkova and P.N. Syachintova was not implemented, however he made a feasible contribution to the further development of the Russian self-propelled artillery. He allowed to work out some design solutions and determine their prospects. In addition, a reserve was created for the development of new chassis based on existing tanks. It is curious that the gun B-10, also not entered service, also influenced the development of artillery. Later, based on it, several new guns were developed.
Solyankin A. G., Pavlov M. V., Pavlov I. V., Zheltov I. G. Domestic armored vehicles. XX century. - M .: Exprint, 2002. - T. 1. 1905 – 1941.
Shirokorad A.B. Encyclopedia of domestic artillery. - Mn .: Harvest. 2000.