The SU-152 and Related Vehicles - читать бесплатно онлайн полную версию книги автора Yuri Igorevich Pasholok (CHAPTER 4. A Personal Order from Stalin) #6

CHAPTER 4. A Personal Order from Stalin

On November 28, 1941, a report from P. F. Solomonov on his trip to Chelyabinsk reached the desk of Military Engineer 2nd Class Anisimov, chief of the Field Artillery Armament Directorate’s 2nd Department. The purpose of his trip was to look into the availability of the KV-1 tank’s armament. The report addressed development in addition to gun supplies. In November 1941, A. N. Bulyshev was managing development of the U-11 and U-12 systems, which involved mounting the M-30 122 mm howitzer and the 52-K 85 mm antiaircraft gun in the KV-1’s turret. The report’s third paragraph is of much greater interest to us.

By order of Joseph Vissarionovich Stalin, the Kirov Factory is developing a triple mount for the KV: One F-34 gun and two 45 mm guns (barrels without recoil mechanisms), with the recoil mechanisms for the triplex taken from the ZIS-5. No 360° field of fire; angle of traverse +/-15° or +/-7.5°, as allowed by the installation; basic load 300 rounds (100 for each weapon); in addition, the triplex to have 3–4 machine guns.

In December, the factory must equip 1/5 of all KV tanks with these triplex systems.

The factory urgently needs the drawings and engineering analysis of the 45 mm tank guns, drawings and engineering analysis of the F-34 (they can make do with on-hand blueprints of the F-34, but the engineering analysis is necessary), and drawings for the ZIS-5 cradle (ruggedized).

The factory also urgently needs four 45 mm tank gun barrels together with their breech mechanisms and, in preparation for testing the triplex, a location, ammunition, and a test program. It is crucially necessary to solve the problem of sights for the triplex.^{1}

A note dated November 29, 1941, attached to the report reiterated the identity of the person who initiated development of the vehicle:

By personal order of People’s Commissar of Defense Comrade Stalin, the Kirov Factory (ChTZ in Chelyabinsk) is developing a triple mount for the KV tank (two 45 mm tank guns and one F-34 76 mm gun).

Urgently deliver four 45 mm tank guns to the Kirov Factory for development of these mounts.

To support the planned total production of KV tanks equipped with triple mounts, by December 1941 the Kirov Factory needs to take delivery of 180 45 mm tank gun barrels with breech mechanisms minus the cradle, recoil mechanisms, semiautomatic mechanisms and optics; and it needs 260 such items by January 1942.^{2}

This unconventional vehicle, which was assigned the factory code 227 and the designation KV-7, was dictated by a desire to increase the KV-1’s firepower. The ZIS-5 76 mm gun fitted to the Chelyabinsk KV-1 was sufficient to defeat enemy tanks, but requests came from the fronts to increase firepower for combating non-armored targets, including light field fortifications. Conceptually, the triple mount would enable the guns to be fired both separately and simultaneously.

^{KV-7 assault tank, December 1941(TsAMO).}

^{Side view of a KV-7 (TsAMO).}

^{Front view of a KV-7; the tank’s massive mantlet and the skirt underneath it are clearly visible (TsAMO).}

^{Rear view of the KV-7 (TsAMO).}

A group of SKB-2 designers led by G. N. Moskvin that had been evacuated to Chelyabinsk was assigned to solve this non-trivial problem. Because the triple mount did not fit into the standard KV-1 turret, a decision was made to install a superstructure in its place (in correspondence, this superstructure was called a “non-rotating turret”). To provide normal working conditions in the fighting compartment for the crew, the superstructure was given the shape of a prism, and its bottom extended over the tracks. In constructing the superstructure, maximum use was made of parts from the KV-1 turret, including the rear machine gun’s ball mount, turret hatch covers, and vision blocks. Recovery tank No. 5161, which had been produced in September 1941, was used to build a KV-7. According to the records, the vehicle was initially equipped with an M-17T engine, and it had seen action on the Leningrad front.

Development of the artillery portion of the triple gun system was assigned to UZTM special design bureau OKB-3. Work on the system, which was developed by engineers N. N. Yefimov and K. N. Ilyin, began in November 1941 and was finished by December 10. The chief designer of the system, which was assigned the factory designation U-13, was F. F. Petrov. L. I. Gorlitsky, who arrived from Leningrad in October 1941, played an important role in developing the U-13. At the time, he was chief of the Kirov Factory’s artillery design bureau. Gorlitsky became deputy chief designer at his new location. The U-13 system was shielded by a common mantlet, which was protected against penetration from beneath by an armor plate.

^{L. I. Gorlitsky, developer of numerous SP guns, the bestknown of which were the SU-122, SU-85, and SU-100. He became UZTM’s chief designer in October 1942 (IZh).}

A test program for the “triple artillery system mounted on a KV tank” was signed on December 17, 1941. Testing was scheduled to last 10 days, but in reality the KV-7 was not tested until December 27, and then it was done at the factory. Capt. P. Solomonov sent a report to the GAU and GABTU based on the test results:

A number of flaws need to be corrected and proving-ground tests urgently performed on the triple mount for the KV-7, which underwent factory testing on December 27, 1941.

Without proving-ground tests, the artillery system cannot be equipped with the necessary sights and vision devices. The TMFD-8 supplied is simply a placeholder for the sight, but modifications are needed for servicing the tank, particularly new scales for aiming. Attachment of a sight at a single point is undesirable.

The Kirov Factory performed proof firing for durability using regular service ammunition. No supercharged rounds were available. No punching, marking, or measurement of the installed parts had been done. The strength of the installed parts must be checked by firing.

The design of the screw-type traversing mechanism with two pivot joints is poor, which causes scattering of shots; in other words, unsatisfactory accuracy. In addition, the traversing mechanism will require constant special monitoring and maintenance. The slightest maladjustment and weakening or wear of the joints will degrade accuracy.

It is necessary and desirable to modify the traversing mechanism. The ideal solution would be to replace it with a sector-type traversing mechanism. The traversing and elevation mechanisms should be equipped with stops. The spent case catcher needs to be modified. Its left and right branches need to be extended forward at least one half the length of the breech, otherwise there is nothing protecting the crew from the recoil. The overall width of the spent case catcher can be reduced, but its sides (right and left) should be somewhat higher.

The position of the headrest needs to be changed; it is not in the right position for the gunner to rest his head on.

The position of the foot switch most be changed; the footrest prevents stowage of several canisters with 76 mm shells in their racks.

The gunner’s seat needs to be improved; the back should be curved.

When the gun is fired at a depressed angle, the recoil will break the roof lamp. The light spots should be located so as to illuminate the recoil indicator scales.

The gunner and the driver need to be linked by a speaking tube, because rough laying is done by the tank.^{3}

The KV-7 underwent the next phase of firing trials on January 5, 1942, at Factory No. 8’s range, where the KV-7 and the KV-8 and had been sent earlier that month. All three guns successfully fired simultaneously only on the third volley, and the accuracy at a range of 400 meters was quite low. A rate of 20–24 rounds per minute was achieved during the firing rate test. When fired separately, the rate of fire was approximately on a par with conventional tanks, but the feasibility of salvo fire was questionable. The F-34 76 mm gun was able to fire three shots in 34 seconds, and the 45 mm tank guns got off five rounds each.

^{The KV-7’s fighting compartment (TsAMO).}

The firing trials coincided with a display of the KV-7 and KV-8 prototypes for senior leadership and resulted in the following report:

The tanks were inspected on January 5, 1942, at Factory No. 8’s test range, Mytishchi Station; attending were the following personnel: Comrade Voroshilov, Deputy Chairman of the Council of People’s Commissars of the USSR; Comrade Malyshev, Deputy Chairman of the Council of People’s Commissars of the USSR and People’s Commissar of the Tank Industry; Comrade Voznesensky, Deputy Chairman of the Council of People’s Commissars of the USSR; Col. Gen. Voronov, Deputy People’s Commissar of Defense of the USSR; Lt. Gen. of Tank Forces Fedorenko, Deputy People’s Commissar of Defense of the USSR and Chief of the Red Army’s GABTU; Army Commissar 2nd Class Biryukov, Military Commissar of GABTU of the Red Army; Comrades Zaltsman, Nosenko, and Petrasyan, Deputy People’s Commissars of the Tank Industry; Col. Gen. Yakovlev, Chief of GAU of the Red Army; Maj. Gen. Melnikov, Chief of Main Directorate of Chemical Defense; Brigade Engineer Korobkov, Chief of the Armor Directorate of GABTU; and Comrade Kotin, Chief Designer, Department No. 1 of the Kirov Factory.

The KV-7 tank

The proposed prototype for the KV-7 assault tank has the same suspension and transmission as the mass-produced KV-1.

In place of a turret capable of rotating 360°, it has a fixed turret with three guns: two 45 mm guns and one 76 mm gun (F-34).

The triple gun system traverses through an angle of +/-7.5°, with a -5° depression angle and a +15° elevation angle.

The guns fire independently.

DT machine guns: 2

Basic load: 200 rounds for the 45 mm guns and 93 rounds for the 76 mm gun. Glacis thickness: 100 mm, turret thickness: 105 mm, and mantlet thickness: 100 mm

Crew: 6

After the inspection and the firing test, the following was noted:

1. Mobility was satisfactory.

2. The glacis and turret armor was unsatisfactory.

3. The practical rate of fire (5–6 salvos per minute) was satisfactory.

4. The layout and location of the triple system and ammunition was satisfactory.

5. The accuracy was unsatisfactory.

The following requirements must be met:

1. The thickness of the armor plates on the front of the turret must be 115–120 mm, and the thickness of the glacis armor must be 110 mm.

2. The gun’s traversing mechanism must be modified to improve accuracy. Improve the optical sight mount.

Modify the trigger mechanisms to enable simultaneous firing from the three systems.

3. One vehicle from the first batch of KV-7 tanks to be produced during the January-February timeframe must have its artillery system tested according to the program of the GAU’s Field Artillery Armament Directorate, in coordination with the Main Armored Forces Directorate, to verify that the noted flaws were corrected during manufacture of the preproduction batch.

Conduct the tests prior to February 15, 1942.

<…>

The Commission considers it desirable to develop and install on the KV-7 a dual gun system consisting of two F-34 76 mm guns and modify that tank to accept the more powerful 122 or 85 mm artillery system.

Development of these prototype artillery systems is hereby assigned to the Kirov Factory’s design bureau of the People’s Commissariat of the Tank Industry.^{4}

^{U-13 triple gun system developed by UZTM’s design bureau (TsAMO).}

The KV-7 was also inspected by military engineers Obukhov and Kivalin, who studied the usability of the U-13 system. Their inspection identified a number of issues. The sight headrest was found to be unusable, and the sight itself was difficult and inconvenient to calibrate. In addition, the scale on the TMFD-8 sight mounted on the U-13 was for the F-32 gun, which had different ballistics from those of the F-34. The mantlet opening for the sight was too large, increasing the danger from enemy fire. The inspection resulted in a suggestion to mount the 9T-7 sight in production models of the triplex and develop a new mount for the sight.

^{Factory drawing of the U-13’s spent-case catcher (SA).}

However, no preproduction batch of the KV-7’s was ever produced. The day after the display of the KV-7 for the commission, Stalin personally drafted State Defense Committee Decree No. 1110ss “On Production of Tanks KV-7 and KV-8,” which reads as follows:

1. Cancel the proposed three-gun model of the KV-7.

2. Mount two 76 mm guns coaxially in the KV-7 with a traverse angle of +/-7.5° and an elevation angle of +15° -5°.

3. Accept the KV-8 into the inventory and begin producing it. Manufacture 10 KV-8 systems in January and 50 in February after correcting the flaws noted in the report of January 5, 1942.

5. Manufacture a production model of the KV-1 with the 122 mm gun by January 25.^{5}

The fact that Stalin himself drafted the State Defense Committee decree on the KV-7 confirms again that he was the project’s initiator. On January 27, 1942, S. A. Ginsburg, Deputy Chief of the 2nd Department of the People’s Commissariat of the Tank Industry, drafted the operational requirement for the new version of the KV-7:

The KV-7 tank is a turretless tank with enhanced armament (two coaxial 76 mm guns).

I. Combat weight: 50-55 tonnes

II. Armor:

a) Mantlet thickness: at least 75 mm

b) Armor protection of the hull: similar to that of the KV-1 tank’s hull

III. Armament:

1. Number of guns (coaxial): 2

- Angle of traverse of the twin guns: +/-7.5°

- Angles of elevation: +20° -5°

2. Number of DT machine guns

a) In the bow: 1

b) In the rear of the fighting compartment: 2

- Machine gun traverse angle: 30°

- Machine gun elevation angles: +15° -5°

IV. Basic load:

1. 76 mm gun rounds: 120–150

2. Number of machine-gun drums: at least 40

V. Crew: 6

VI. Tank hull

- The KV-7 hull is similar to that of the KV-1 except for the upper portion of the fighting compartment and parts linked directly to the system mount.

VII. Fighting compartment and armament installation

1. The fighting compartment must allow for convenient placement of the gun crew and have instruments for 360° observation.

2. The fuel tanks may be located on the bottom of the fighting compartment to increase the amount of ammunition that can be carried and its convenient placement.

3. The twin 76 mm guns must be capable of firing salvos and firing separately.

4. The rate of fire during salvo firing (number of salvos per minute) must be close to that of the KV-1; when both guns are fired separately (one at a time) the rate of fire must exceed that of the KV-1 by 70–80%.

VIII. The tank’s mobility, engine, suspension, and communications equipment must be similar to that of the KV-1.

Note: the factory may alter and supplement this operational requirement to improve the design in coordination with the People’s Defense Commissariat, the Armor Directorate of the Red Army, and the People’s Commissariat of the Tank Industry.^{6}

^{KV-7 assault tank with U-13 triple gun system, 1:35 scale drawing.}

^{KV-7 assault tank with U-14 twin gun system, Chelyabinsk, spring 1942 (IZh).}

As was the case with the gun system for the first version of the KV-7, work on the twin ZIS-5 76 mm guns was assigned to the Ural Heavy Machinery Plant. The project was overseen by L. I. Gorlitsky (on drawings, he is identified as the chief designer), and N. V. Kurin and G. F. Ksyunin worked on the system that was assigned the factory designation U-14. Judging by the dates listed on the drawings of individual parts, design work began not later than January 25, 1942; that is, before the operational requirement for the upgraded KV-7 was issued. Design work on the U-14 lasted until mid-February, and work to manufacture the upgraded KV-7 began in the second half of that month. The assault tank was not built from scratch: the existing KV-7 with the U-13 system was modified. The superstructure itself did not need to be altered; the changes affected only the mantlet and the ammunition storage rack.

The test program for the upgraded KV-7 was drafted by March 7, 1942. In addition to the firing trials during which 400 rounds were to be fired, it was proposed that the vehicle be driven a total of 50 kilometers. However, the tests had to be postponed because the Chelyabinsk Kirov Factory was occupied with other projects at the time. As a result, the firing trials were held much later, and no mobility test was performed. Kirov Factory chief designer, Maj. Gen. Zh. Ya. Kotin was given the following report about the tests conducted on May 16, 1942:

Assembly of the KV-7 tank was completed on May 11, 1942, and on the 14th it underwent preliminary testing at the Kopeysk Test Range. Seventeen highexplosive fragmentation shells were fired from both systems, 5 by individual fire and 12 in salvos. A 1.5 X 1.5 meter target at a range of 800 meters was used.

The following preliminary conclusion can be drawn from the data:

1. The accuracy of the twin systems in firing from a halt is good. After zeroing, 11 rounds fell in an ellipse with a long axis of 40 meters and the short axis of 3 meters.

2. The rate of fire was 6–7 salvos per minute. Due to system imbalance and the self-braking elevation mechanism—a sector-type (elevation) mechanism mounted on the twin guns—the elevation angle increased spontaneously by 25 mils after each salvo.

3. The twin gun traversing mechanism requires both hands to operate, which is completely unacceptable.

4. The placement of shell cases in an inset in the turret causes great difficulty during operation and cannot be accepted. Open storage must be used.

5. The effort required to operate the twin gun trigger mechanism during salvo firing is too great and must be cut at least in half.

6. No retraction device is provided for the twin guns; the rear wall of the turret must be adapted for that purpose, simultaneously making it an entryway for the crew.^{7}

According to development plans at Experimental Tank Plant No. 100 of the People’s Commissariat of the Tank Industry (located in Chelyabinsk), which had been established in March 1942, the upgraded KV-7 was to undergo factory tests from June 1 through 10, followed by state testing. That did not take place: interest in an assault tank had waned, and Factory No. 100 was fully engaged in developing the KV-1S. That meant other development projects had to be postponed. The main reason the KV-7 project stopped was that design work to install the ML-20 152 mm gun howitzer in it was in full swing by June 1942.

^{Modified KV-7 assault tank (IZh).}

The assault tank story might have ended here, but work on it did not cease. The KV-7 came up again in October 1942. P. F. Solomonov (a major at the time) inspected the SP gun during a business trip to the Kirov Factory. At Solomonov’s insistence, the KV-7 was taken for a 15-kilometer test run. Firing trials could not be conducted because the traversing mechanism was malfunctioning. On November 10, Kotin received a letter from the chief of the GAU’s Artillery Committee, Col. Gen. V. I. Khokhlov, that read as follows:

The Kirov Factory of the People’s Commissariat of the Tank Industry of the USSR has built a KV-7 tank with a non-rotating prismatic turret and twin ZIS-5 76 mm tank guns installed. After undergoing factory tests, the tank remains at the experimental factory of the People’s Commissariat of the Tank Industry, and no decisions have been made concerning it.

It is the opinion of the Artillery Committee that this system should be sent for proving-ground tests and troop trials.

The troop trials should be performed under actual combat conditions, and the proving-ground tests should be done at the Tagil Test Range of the People’s Commissariat of Munitions of the USSR.

The following actions must be taken before the KV-7 is sent for testing:

1. Install a commander’s observation cupola.

2. Inspect and repair the transmission, powerplant, and running gear.

3. Check the artillery system and repair and adjust the laying devices (elevation and traverse).

4. Adjust the trigger mechanisms

5. Modify the spent case catcher for greater convenience in loading.

If you agree, please task Factory No. 100 of the People’s Commissariat of the Tank Industry to perform the necessary work and provide a crew for the tank.^{8}

The KV-7 was neither upgraded, nor did it undergo troop trials. S. A. Afonin, chief of the GABTU’s Armor Directorate, felt that it made no sense to upgrade the tank, which had undergone a number of tests by December 10, 1942, because it had failed to fire a synchronous salvo. Also, instead of pairing the ZIS-5 76 mm guns, a single gun of a much larger caliber should be mounted, which Factory No. 100 was currently engaged in doing. However, work on the KV-7 project did not end there.

Decrees No. 12016ss and 12017ss issued on June 27, 1942, by the People’s Council of Commissars of the USSR tasked the Saratov Gear-Cutting Machinery Plant to manufacture prototypes of a planetary transmission. A team led by G. I. Zaichik at the Bauman Institute of Mechanical Engineering in Moscow developed this transmission. Manufacture of the transmission was delayed: instead of August, two prototypes were made in December 1942, and they arrived at Factory No. 100 on the 30th. A team of designers from the Bauman Institute arrived in Chelyabinsk on January 2 to supervise the installation. The KV-7 was selected as the tank for use in testing the planetary transmission. Installation of the new transmission was delayed because Factory No. 100 was occupied with other projects. Instead of January 16 as instructed by I. M. Zaltsman, People’s Commissar of the Tank Industry, the installation was completed only on February 17. It is possible that the delay at this stage was deliberate, because a different transmission had been undergoing testing on KV-1S No. 15002 since November 19, 1942—one designed by Eng. Col. A. I. Blagonravov.

The low build quality of the planetary transmission was apparent during the first few kilometers of the tests. All of the bronze rings were replaced with steel rings and the control ball bearings with forged needle bearings.

^{Front view of KV-7 with twin U-14 guns (IZh).}

^{KV-7 assault tank with twin U-14 guns, 1:35 scale drawing.}

^{U-14 twin gun trigger mechanism (SA).}

Furthermore, an oil leak needed to be corrected and the Ferodo brakes replaced with cast-iron brake shoes. After the defects were corrected, the transmission was again installed in the KV-7, after which it traveled a distance of 545 km on March 4 without a problem. In a memorandum to People’s Commissar Zaltsman on June 5, 1943, the chief of the GABTU’s Armor Directorate stated the following:

The tank with a planetary transmission is becoming more maneuverable and responsive. Changing gears is accomplished easily and quickly without losing speed.

The design defects identified during testing—oil leaks through seals, increased effort on the pedals and control levers, no automatic adjustment of brake bands—can be corrected when the transmission is refined for mass production.

In order to completely determine the performance of the planetary transmission, testing on the tank with this transmission is extended until the full guaranteed distance of 2000 km is achieved.^{9}

^{The KV-7 assault tank with twin U-14 guns was to go to the front in this configuration, 1:35 scale drawing.}

Meanwhile, the testing dragged on. A final reduction gear failed in April after a 160 km run (excluding the 545 km traveled during February-March). Testing of the planetary transmission continued after repairs were made. The tank was driven a total of 843 km between February and April 1943, and then strange things began happening. Factory No. 100 delayed completion of testing for various reasons, and the KV-7 did not move for the entire month of May. The situation was the same in June. Factory No. 100’s management cited a simple lack of manpower as the reason, although the true reason was unwillingness to work with a transmission developed elsewhere. According to reports by Eng. Maj. Dolitsky, deputy to the senior military representative of GABTU’s Tank Directorate, only two people would be needed to correct the defects and continue testing. It is difficult to believe that the factory did not have them. The situation continued unchanged in July and August 1943, even though the GABTU management sent a letter “up the chain” demanding that testing be continued. In September, tests on the planetary transmission designed by Zaychik simply vanished from Factory No. 100’s plans, and it reported on November 30 that assembly of a planetary transmission designed by Factory No. 100’s special design bureau was complete. Development was delayed, and in the spring of 1944 the transmission was installed in the first prototype of heavy tank Object 701. The conflict continued: the second prototype of the new tank had the transmission developed by Zaychik’s team.

Judging from the correspondence, the second phase of testing on the planetary transmission did not take place. The KV-7 traveled another 1089 km, after which the transmission was removed. This marked the end of this vehicle’s career. According to a decision by Factory No. 100’s management, in late December 1943 the KV-7, KV-9, and KV-12 were decommissioned and scrapped.

Despite the unfortunate fate and lack of soundness of the concept of an assault tank equipped with a salvo fire system, the KV-7 was a major milestone in the history of the Soviet tank industry. It was actually the first wartime Soviet heavy SP assault gun, and its design was the point of departure for the development of SP guns of that class. Development along those lines actually began simultaneously with work on the KV-7 that was equipped with the U-14. In addition, the scheme featuring installation of weapons in a frame was subsequently used in a number of wartime Soviet SP guns.