M-30 howitzer plus thirty-four chassis
For the first year and a half of the Great Patriotic War, the Red Army fought with virtually no self-propelled artillery. The few pre-war samples were quickly destroyed, and the hastily built in 1941 ZIS-30 were created without taking into account and analyzing the real needs of the units fighting at the front. Meanwhile, the Wehrmacht had a significant number of various self-propelled artillery installations, the production of which was constantly increasing.
On April 15, 1942, the plenum of the GAU Artillery Committee with the participation of representatives from industry and troops, as well as the People's Commissariat of Armaments, recognized the development of both self-propelled artillery units for infantry support with a 76-mm ZIS-3 cannon and a 122-mm M-30 howitzer and self-propelled fighters pillboxes with 152-mm howitzer cannon ML-20. To combat air targets, it was proposed to design a 37-mm anti-aircraft automatic self-propelled gun.
Howitzer M-30
CRAZY TANK U-34
The decision of the plenum was approved by the State Defense Committee. Basically, it boiled down to the creation of such a system of artillery weapons, which would provide support and accompaniment of the advancing infantry and tank subunits with the fire of guns, capable in any battle conditions and at all its stages to follow in the battle formations of troops and continuously conduct effective fire.
In the summer of 1942, in the design department of the Uralmashplant, engineers N. V. Kurin and G. F. Ksyunin prepared an initiative project for a medium self-propelled gun mount U-34 using the T-34 tank and its weapons as a base. The U-34 retained the chassis, main body elements and weapons from the thirty-four, but differed in the absence of a rotating turret and a course machine gun, as well as a slightly increased armor thickness (in some places up to 60 mm).
Instead of a turret, a stationary armored wheelhouse was installed on the SPG hull, in the embrasure of which the gun could have horizontal guidance in the 20 ° sector, and vertical - like a tank. The mass of the new car was about 2 tons less than that of the thirty-four, in addition, the self-propelled gun was 700 mm lower. Its design has been greatly simplified due to the absence of labor-intensive components in the manufacture: towers, shoulder straps, etc.
The U-34 project was approved by the leadership of the People's Commissariat of Heavy Industry (NKTP). As the main variant of a combat vehicle - a tank destroyer and fire support, the self-propelled gun was intended to be launched into mass production. The first two prototypes were supposed to be manufactured and sent for testing by October 1, 1942. However, by the end of August, work on the U-34 was stopped - Uralmash began hastily to prepare the release of the T-34 tanks.
CREATE A CAR IN THE SHORTEST TIME
But the process of developing domestic ACS did not stop there. Already on October 19, 1942, the State Defense Committee adopted a decree on the manufacture of self-propelled artillery - light with 37-mm and 76-mm guns and medium - with 122-mm. The creation of prototypes of medium ACS was entrusted to two enterprises: Uralmash and Plant No. 592 of the People's Commissariat of Armaments. Shortly before that, in June - August 1942, specialists from the artillery plant No. 9 in Sverdlovsk (now Yekaterinburg) made a draft design of a self-propelled installation of a 122 mm M-30 howitzer on the chassis of a T-34 tank.
The experience gained at the same time made it possible to draw up very detailed tactical and technical requirements for a medium artillery self-propelled gun with a 122-mm gun. They were attached to the GKO decree and obliged during the design to leave most of the M-30 units unchanged: the entire receiver group of recoil devices, the upper machine, guidance mechanisms and sighting devices. To fulfill these conditions, the howitzer had to be mounted on a pedestal attached to the bottom of the vehicle, and the recoil length of the gun should be kept unchanged, equal to 1100 mm (with the recoil device cylinders protruding in front of the frontal hull sheet for a considerable length). The tactical and technical requirements also obliged to completely preserve all the engine-transmission units of the thirty-four, and the mass of the ACS should not exceed the mass of the tank.
To implement the GKO decision, by order of the People's Commissar of Tank Industry No. 721 of October 22, 1942, a Special Design Group (OCG) was formed at Uralmashzavod consisting of N. V. Kurin, G. F. Ksyunin, A. D. Nekhlyudov, K. N. Ilyin, I. I. Emmanuilov, I. S. Sazonov and others. The work was supervised by L. I. Gorlitsky and the deputy people's commissar of the tank industry Zh. Ya. Kotin. The installation was assigned the factory index U-35, but later, at the direction of the GBTU of the Red Army, it was changed to SU-122. A very short time was allotted for the creation of the machine: state tests of the prototype were supposed to begin on November 25.
After the design department of Uralmash completed the working design of the self-propelled gun, the interdepartmental commission of representatives of the GAU and NKTP studied it in detail. At the same time, the installation option, previously proposed by plant No. 9, was also considered, since both enterprises claimed to manufacture ACS according to their own projects. The commission gave preference to the development of the Uralmash workers, since it had the best technical characteristics.
To reduce the production time of the prototype, the preparation of the drawings took place in close contact between the designers and technologists. Drawings for all large and labor-intensive parts were transferred to the shops before the entire design study was completed. The timing and quality of manufacturing of the most critical parts was under special supervision.
In the time allotted for the task, it was not possible to make all the necessary fixtures and fittings. Therefore, the prototype was assembled with a lot of fitting work. The complete set of technological equipment was designed in parallel and intended for subsequent serial production. The assembly of the prototype was completed on November 30, 1942. On the same day, factory tests were carried out: a run of 50 km and firing 20 shots at the factory range in Krasny.
After that, only those changes were made to the design of the artillery self-propelled gun that were required for the successful conduct of state tests: they mounted the seats, ammunition stowage, viewing devices, an exhaust tower fan and other equipment, provided the guidance angles required by TTT. The rest of the wishes for improving the design of the ACS were taken into account when working out the drawings of the experimental series. State tests of two samples of self-propelled units manufactured by Uralmash and Plant No. 592 were carried out from 5 to 9 December 1942 at the Gorokhovets test site.
On December 28, 1942, one of the vehicles of the December setting program was tested at the factory range, which consisted of a run of 50 km and firing 40 shots. No breakdowns or shortcomings were noted. As a result, the entire installation batch of self-propelled guns - 25 vehicles - was recognized as suitable for admission to the Red Army and sent to the Self-Propelled Artillery Training Center. A group of plant workers - designers, drivers, locksmiths - also went there. This group included the deputy chief designer L. I. Gorlitsky, the driver Boldyrev, the senior foreman of the assembly shop Ryzhkin and other specialists.
FURTHER IMPROVEMENT
In the course of serial production, numerous changes were made to the design of the ACS. Therefore, self-propelled guns of different production series were different from each other. So, for example, the first eight SU-122s, which entered the Training Center, did not have not only the exhaust fans of the fighting compartment, but also the places for their attachment. Fighting vehicles of early releases, which did not receive special tank radio stations, were adapted by the forces of the center for the installation of aircraft-type radio stations transferred from the People's Commissariat of the aviation industry.
In general, the Self-Propelled Artillery Training Center described the new self-propelled guns as excessively heavy (weight - 31.5 tons), not very reliable (frequent chassis breakdowns) and difficult to learn. However, over time, the attitude towards the SU-122 changed for the better.
The vehicles of the second series (February-March 1943) received a simplified gun mask and a number of changes in the interior. In addition, cylindrical fuel and oil tanks were introduced, but until the summer of 1943 they were not unified with T-34 tanks. In general, the total number of parts borrowed from the T-34 tank reached 75%. In the spring and summer of 1943, in order to increase the space for ammunition, a second loader was removed from the crews of some vehicles. The crew decreased from 6 to 5 people, which negatively affected the rate of fire. Part of the SU-122 received an additional crew compartment fan, which was installed on the aft deckhouse.
The production of self-propelled guns continued at Uralmash from December 1942 to August 1943. During this period, the plant produced 637 self-propelled guns. For work on the creation of the installation, Deputy Chief Designer L. I. Gorlitsky and leading engineer of the enterprise N. V. Kurin were awarded the Order of the Red Star and the Stalin Prize of the 2nd degree.
In the finalized design of the SU-122 serial ACS, the entire engine-transmission group and the chassis of the T-34 tank remained unchanged, the fully armored control compartment and the fighting compartment were located in the front of the vehicle, the mass of the installation (29.6 tons) was less than the mass of the tank. T-34, speed, cross-country ability and maneuverability remained the same.
The armament of the self-propelled guns used the swinging and rotating parts of the 122-mm field howitzer of the 1938 model - the M-30. Barrel length - 22, 7 caliber. The upper pin of the howitzer was installed in the socket of a special pedestal mounted in the front of the hull bottom. A swinging part with a standard barrel, cradle, recoil devices, sight and guidance mechanisms was attached to the pins of the machine. The need to arm the swinging part required strengthening the spring balancing mechanism, which was done without changing its dimensions.
Ammunition - 40 rounds of separate-case loading, mainly high-explosive fragmentation. In some cases, cumulative shells weighing 13.4 kg, capable of penetrating armor of 100-120 mm, were used to combat enemy tanks at ranges of up to 1000 m. The mass of the high-explosive fragmentation projectile is 21, 7 kg. For self-defense of the crew, the installation was supplied with two PPSh submachine guns (20 discs - 1420 rounds) and 20 F-1 hand grenades.
For direct fire and from closed firing positions, one panoramic sight with a semi-independent line of sight was used. The head of the panorama went under the armored visor of the hull with side holes for viewing the terrain, which, if necessary, could be closed with hinged covers. The commander of the vehicle had a PTK-5 periscope tank observation device, which made it possible to carry out all-round observation of the terrain, and a 9RM radio station. The commander of the vehicle, in addition to his direct duties, performed the work of the right gunner in the elevation angle.
The relatively large number of the crew (5 people) is explained by the fact that the 122-mm howitzer had a piston bolt, separate loading and a guidance mechanism spaced out on both sides of the gun (on the left was the flywheel of the rotary screw mechanism, and on the right was the flywheel of the sector lifting mechanism). The horizontal guidance angle of the gun was 20 ° (10 ° per side), vertical - from + 25 ° to -3 °.
PARTS OF RVGK
When creating the first separate self-propelled artillery units of the Red Army, a regiment was adopted as the main organizational unit, which received the name "Self-propelled artillery regiment of the Reserve of the Supreme High Command (RVGK)". The first self-propelled artillery regiments (1433 and 1434) were formed in December 1942. They had a mixed composition, and each consisted of six batteries. The regiment's four batteries were armed with four SU-76 light self-propelled guns and two batteries - four SU-122 units.
Each battery had two platoons of two installations. Self-propelled guns were not provided for battery commanders. In total, the regiment was armed with 17 SU-76 self-propelled guns (including one for the regiment commander) and eight SU-122. For this state, it was supposed to form 30 regiments. The first self-propelled artillery regiments were intended to be transferred to tank and mechanized corps, but in connection with the commencement of the operation to break the blockade of Leningrad, they were sent to the Volkhov front at the end of January 1943.
The new regiments took their first battle on February 14 in a private operation of the 54th Army in the Smerdyn area. As a result, in 4-6 days of fighting, 47 bunkers were destroyed, 5 mortar batteries were suppressed, 14 anti-tank guns were destroyed, 4 ammunition depots were burned. On the Volkhov front, factory test drivers took part in some operations. In particular, Boldyrev was awarded the medal "For Military Merit" for the successful completion of a separate task of the test driver of the Uralmash plant.
Self-propelled artillery regiments of the RVGK of mixed composition were primarily intended to reinforce tank units as their mobile military artillery, as well as to support infantry and tanks of combined-arms formations as escort artillery. At the same time, it was assumed and considered possible to involve the self-propelled guns in firing from closed firing positions.
However, in the course of the battles, in which the mixed self-propelled artillery regiments took part, a number of organizational shortcomings came to light. The presence of various types of self-propelled guns in the regiment made it difficult to control them, complicating the supply of ammunition, fuel (the SU-76 engines ran on gasoline, and the SU-122 - on diesel fuel), lubricants, spare parts, as well as their additional staffing. This organization of self-propelled artillery regiments had a negative effect on the repairs. To eliminate all these shortcomings, it was necessary to move on to recruiting regiments with the same type of material.
The training of personnel for self-propelled artillery units throughout the war was carried out by the Self-Propelled Artillery Training Center, located in the village of Klyazma, Moscow Region. The center was founded on November 25, 1942. Its tasks are the formation, training and sending to the front of self-propelled artillery regiments and marching batteries. To train driver mechanics for the SU-122, the 32nd tank training battalion was transferred from the armored forces, on the basis of which the 19th self-propelled artillery training regiment was created in Sverdlovsk.
The batteries formed in the training regiment were sent to the Training Center, where they were reduced to regiments, replenished with personnel from the reserve regiment, and equipped with military-technical equipment and vehicles. After the coordination of the units, the regiments were sent to the active army. The timing of the preparation of self-propelled artillery units depended on the situation at the front, the plans of the Supreme Command Headquarters and the availability of materiel. On average, the formation of a self-propelled artillery regiment took from 15 to 35 days, but if the situation required it, then in the presence of materiel and trained personnel, separate regiments were formed within 1-2 days. Their coordination was carried out already at the front.
COMBAT PRACTICE
In 1943, in the course of training and combat operations, the tactics of using self-propelled artillery were developed, which remained until the end of the war. It consisted in the fact that with the beginning of the movement of tanks in the attack, the self-propelled guns from occupied positions with direct fire destroyed the revived and re-emerging anti-tank guns and other, more important firing points of the enemy. The movement of the self-propelled guns to the next line began when the tanks and infantry reached the first enemy trench, while part of the self-propelled artillery batteries moved forward, while the other continued to fire at the observed targets from the old positions. Then these batteries went forward under cover of fire from the self-propelled guns that had already deployed on the new line.
During the offensive, self-propelled artillery installations moved in the battle formations of infantry and tanks, not breaking away from the supported units by more than 200-300 m, which made it possible to constantly carry out fire interaction with them. Thus, jumps from one line to another were made often, so the self-propelled guns were at each firing line for only 3-5 minutes, less often - 7-10. During this period of time, they managed to suppress one, rarely two targets. At the same time, this method of moving the battle formation of self-propelled artillery contributed to the continuity of the accompaniment of infantry and tanks.
Self-propelled artillery installations usually fired at intervals between tanks or infantry units, destroying the most active enemy fire weapons. During the offensive, they fired either from short stops - with one aimed shot from a gun at a specific target, or lingering at any cover - with three or four aimed shots. In some cases, the self-propelled guns took up a firing position in advance and fired from behind cover for a long time. At the same time, the shooting could be carried out more calmly, until the complete destruction of several targets, after which a leap forward was made to the next line or until the advanced rifle and tank subunits were included in the battle formation. Thus, in the combat employment of self-propelled artillery, three main methods of performing fire missions began to differ: "from short stops", "from stops" and "from a place".
Shooting from the self-propelled guns was carried out within the range of actual fire and depended on the situation, terrain and the nature of the target. So, for example, self-propelled guns of the 1443rd self-propelled artillery regiment on the Volkhov front in February 1943, conducting hostilities on wooded and swampy terrain, which limited the possibilities of firing, opened fire on all targets at ranges not exceeding 400-700 m, and at bunkers - 200-300 m. To destroy bunkers in these conditions, on average, 6-7 122-mm shells were required. In most cases, the shooting was conducted at targets that the crews themselves were looking for. Infantry landings (when they were available) rendered significant assistance in this. Only 25% of all detected targets were destroyed at the direction of the battery commanders. If the situation forced the use of concentrated fire or fire from closed positions, then fire control was centralized in the hands of the battery commander or even the regiment commander.
As for the SU-122, the formation of self-propelled artillery regiments with the same type of installations began in April 1943. In such a regiment there were 16 SU-122 self-propelled guns, which until the beginning of 1944 continued to be used to escort infantry and tanks. However, this use of it was not effective enough due to the low initial velocity of the projectile - 515 m / s and, consequently, the low flatness of its trajectory. The new SU-85 self-propelled gun, which had been delivered to the troops in much larger numbers since August 1943, quickly replaced its predecessor on the battlefield.
