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 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 personneclass="underline" 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.
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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}
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.
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 hulclass="underline" 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.