The KV-85 Heavy Tank was not an epochal machine in the history of Russian tank design and construction. Although it was not produced in the thousands, this tank still made a contribution to the victory over fascism.
The first attempts to arm a tank with a powerful 85-90 mm gun were undertaken before the war, in 1939. Development of these weapons was going on at the same time. Tests were conducted with production models of the T-28 and KV, but for a number of reasons were not conducted on the armament. Efforts of this nature were temporarily halted with the beginning of the Great Patriotic War.
As early as December 1941, Uralmash Factory recommended the U-12 85 mm gun, developed by designers Sidorenko and Usenko, for arming of the KV tank. But the high cost of the gun was excessive for that time and it was recognized as not cost effective to accept it for the armament.
In the spring of 1942 three design groups submitted proposals to the NKV with 85mm tank gun projects: TsAKB (chief-engineer V. Grabin), Kalinin OKB #8, and Factory #92 KB (KB means design bureau) of chief-engineer V. Savin.
All the design bureaus recommended utilization of the mounting and recoil systems of the ZIS-5 or F-34 76 mm tank gun, but mounting in them of the 85mm barrel with the ballistics of the type-1939 antiaircraft gun. For compensation of the recoil the TsAKB recommended increase of the recoil mass, OKB #8 - the employment of the muzzle brake of the anti-aircraft cannon, and Savin's design bureau - a redesigned muzzle brake.
All three variants were rejected because at that time, in the opinion of the technical directorate of the NKV and the leadership of the NKTP, transition to an 85 mm gun was not justified because the per-round-fired cost of an 85 mm gun was significantly greater than that of a 76 mm gun.
However, in 1943, after the appearance on the battlefield of the new German Tiger and Panther tanks, and also the inadequate high explosive effects of the 76 mm gun against new field fortifications, interest in the 85 mm gun re-emerged with new strength.
Projects that had been suggested in 1941-1942 were reexamined, but the most promising of them - the Kalinin Factory #8 design -was rejected because it required use of a muzzle brake, which at that time was considered highly undesirable in a tank gun.
In the winter of 1943, the TsAKB completed the design of a new tank and self-propelled gun cannon, the S-18, which was approved by the NKV technical directorate. Factory #9 was ordered to prepare two trial models in March 1943 (at that time the TsAKB did not have its own production facility). But the preparation of these guns was protracted. When they were finally subjected to testing it was revealed that the guns had been prepared with deviations from the blueprints. Factory #9 KB, under the leadership of F. Petrov, argued that the modifications were appropriate. V. Grabin argued for his original design. Nothing came of the disagreement. The test guns performed normally and rather than correct deficiencies that were uncovered during the tests, the designers and builders undertook liberally to pour dirt on each other. As a result, for testing of the first trial tank - "Object 237" - a non-working model of the S-18 gun was installed in its turret. After the deficiencies of the S-18 were exposed, it was not mounted on the tank but rather given over for prototypes of the SU-85 (SU-85-I and SU-85-IV).
Parallel with the development of the S-18, the TsAKB designed yet another variant of an 85 mm tank gun for the KV-1S and JS tanks, which was designated as the S-31. For this reason this gun was being developed right away in two variants -with the ballistics of the 85 mm anti-aircraft gun (muzzle velocity of 790-800 m/sec) and with improved ballistics (muzzle velocity of 880-900 m/sec). Factory #92 conducted the preparation and testing of the gun, which showed that in comparison with the S-18 the new cannons were much more technological (simpler and cheaper in production). However, the gun with the improved ballistics demanded development of a new propellant in the existing casing. This complex task was not resolved in the time allotted (by 1 October 1943) and all remaining efforts on the 85 mm tank gun were limited to the ballistics of the 85 mm Anti-Aircraft Gun Model 1939.
Meanwhile, the Factory #9 design bureau reworked the design of the U-12 Gun and in May 1943 recommended their own variant of the 85 mm tank gun. The new model received the designation D-5T and differed from the U-12 in that it had a semi-automatic camming-type mechanism borrowed from the ZIS-5 gun, along with several recoil and return components. The solid construction of the gun and the small length of its recoil permitted it to be mounted in the turret of any existing heavy tank without reworking of the turret. The S-31 had an advantage over the S-18 by having a small recoil length and reduced mass of breech components, but it had a greater number of small parts that required precise machining.
Four tanks (two JS and two KV-1S) armed with the 85 mm S-31 and D-5T guns were tested jointly. This test demonstrated the great operational superiority of the D-5T gun and it was accepted for armament.
For these tests the S-31 gun was mounted in the standard KV-1S turret with minimal reworking. The crew had been reduced to four men. This tank (Object 231, serial number 30751-51) is now preserved at the VIM BTVT at Kubinka.
Despite the success with the KV, work on a new future JS-85 tank was dragged out at the same time that the front was demanding new tanks with powerful armaments. It was necessary to withstand for several months before the introduction of the JS-85. A way out was found. The design bureau of J. Y. Kotin decided to come up with a modernisation of the KV-1S tank, mounting on it the turret of the JS-85 tank with the D-5T gun.
The following work was accomplished during the mounting of the new turret on the KV-1S: the under-turret box, in which the enlarged-diameter ring of the improved tank turret fit with difficulty, was widened. The basic load of 70 main gun rounds was stored in improved racks. With the placing of the gun and the ammunition racks, the designers had to delete the fifth crewmember -the gunner-radio operator, for whom there was no longer any space. The hull-mounted DT machine-gun, which previously was carried in a movable ball mounting, was now fixed. The power pack, transmission, and suspension components were taken straight from the KV-1S.
The first KV-85s were re-worked from excess KV-1S hulls, welding up the hole for the ball-mounted hull machine gun. The incorrect opinion has appeared in Western literature that there was a "second version" of the KV-85 with a flexible front machine gun. This confusion most likely arose as a result of study by Western experts of the only KV-85 tank that has been preserved to this day (monument in Avtovo, St.Peterburg), where a mistake was made in the restoration process. According to archival data, 148 KV-85 tanks were produced; they were sent to the front beginning in September 1943. Simultaneously, output of the KV-1S tank was continued until December 1943.
Factory #9 was given an order for production of the D-5T, but it turned out to be rather difficult for the factory. The factory was completely incapable of simultaneous production of guns for the JS-85 and KV-85 and for the T-34-85. Factories #8 and #13 were dedicated to mass production of the D-5T. These problems with production of the gun prevented the KV-85 from becoming a mass tank. By the spring of 1944 the JS-2 entered mass production with incomparably greater armament and armor, and the subsequent fate of the KV-85 (and also the JS-85) was sealed.
A great portion of the KV-85s in the guards tank breakthrough regiments ended up on the Southern Front (2nd formation), later the 4th Ukrainian Front, where they participated in the liberation of Ukraine and the Crimea. Because on the whole our tank was not superior to the German heavy tanks, battles were fought with varied success. The results depended primarily on the training of the crews of the opposing sides and on the tactics they selected for the engagement.
The 34th Guards Heavy Tank Breakthrough Regiment (TTPP) (total 20 KV-85 tanks), which together with the 40th Heavy Self-Propelled Artillery Regiment (TSAP) (total 9 SU-152s), fought in the area of the village Ekaterinovka on 20-25 November 1943 as element of the 28th Army of the 4th Ukrainian Front.
On 20 November both regiments in a two-echelon formation attacked enemy positions that in addition to artillery had Pz.Kpfw IV Ausf.H and Marder II self-propelled guns (up to 18) dug into their positions. In the course of the day the tankers and self-propelled artillerymen managed to capture the first lines of the German trenches, losing 6 KV-85 tanks (left in enemy-controlled zone) and 6 SU-152 Assault Guns in the process. On the second day of the battle up to 10 Pz.Kpfw IV Ausf. H undertook a counterattack on the positions of Soviet troops. The attack was beaten off by the efforts of the infantry and both tank regiments, costing the enemy five tanks without any losses on Soviet side. On 23 November all serviceable vehicles in the regiment again attacked the German positions, broke through their defenses, and advanced 5 kilometers in deep. An additional two KV-85 tanks were lost in this operation (one of them burned up). The 34th Guards TTPP was sent to the rear for repair on 23 November and only the 40th TSAP continued to fight until 28 November, losing one or two vehicles daily in combat.
Along with the 19th Tank Corps, the 1452d Separate Self-Propelled Artillery Regiment (SAP), which was equipped with 11 KV-85s, 5 KV-1S's, 6 SU-152s, and also 3 SU-76s, participated in the liberation of the Crimea. It seems that because of a severe shortage of self-propelled guns, someone decided to equip the SAP with KV tanks, which had the most destructive armament of all the tanks presented in the Crimea at that time. The 19th Tank Corps had only the T-34s and light tanks, and the enemy had two brigades of assault guns: the 191st and 279th under the command of Major Mueller and Captain Hoppe (altogether the XVII German Army had 215 tanks and self-propelled guns, primarily the StuG III with 75 mm cannons). But for a number of reasons associated with the leadership of the operations, the regiment fought with the masterfully retreating German infantry, who broadly employed mines.
On 8 April 1944, in accordance with the order of the commander of the 3rd Guards Rifle Division, to which the regiment (11 KV-85, 5 KV-1S, 2 SU-152) was operationally subordinated, the tankers and infantry, who had concentrated 1.6 km south of Turetskiy wall, attacked the enemy positions from the west to capture the town Armyansk. Several minutes after the launching of the attack the regiment blundered into a minefield that was unknown for the Russians and therefore not marked on the map. Sappers designated for mine clearing were on the tanks and could not dismount because the Germans opened up on them with all types of weapons. Paradoxically, three hours after the launching of the attack, the 1452nd SAP still managed to break through the enemy defenses, losing 1 burned-out KV-85, 3 KV-85s blown up by mines, and 5 KV-1S's, 4 KV-85s, and 2 SU-152s damaged by enemy gunfire. No personnel were killed, but 2 officers and 4 soldiers were wounded. The 3 remaining operational KV-85s and 5 KV-1S's with an assault force from 3rd Guards Rifle Division reached the town Armyansk at 14:00 on 8 April. The regiment had accomplished its assigned mission. As a result of this battle, 11 pillboxes, 5 antitank guns, and up to 200 enemy soldiers and officers were destroyed. Thus, the basic losses in personnel and equipment were caused by insufficiently competent leadership, which was unable to organize coordination of various branches of troops during the breakthrough of the German defense.
The regiment repaired its equipment until 10 April 1944 and on 11 April a tank group (3 KV-85s 2 SU-152s, 2 SU-76s) of 1452nd SAP again attacked the German defenses in the area of Ishun. Tanks supported the infantry of the 3rd Guards Rifle Division. Because reconnaissance was not conducted, the tanks rolled into an 8-meter antitank ditch and special tank traps that were similar to ditches. The attack failed. A pair of KV-85s and SU-76s was recovered from the ditches with the aid of tractors. After this grievous experience of the use of heavy tanks, the command of 2nd Guards Army decided to make a radical change in the tactics of the employment of this unit. The more so because on 10-11 April the Germans began to organize the withdrawal of their forces toward Sevastopol. On order of the commander of 2nd Guards Army (#005/OP of 10 April 1944), the vehicles of 1452nd SAP and 512th Independent Flamethrower Tank Battalion (OOTB) were parceled out to army mobile detachments. These detachments consisted of infantry on Studebaker trucks and also tanks and self-propelled guns, and had the mission as rapidly as possible to break through to Sevastopol. KV-85 tanks also were assigned to these detachments.
Engagements with the StuG III were exceedingly few -the Germans were retreating under the cover of artillery and mine fields. A group under the command of Hero of the Soviet Union Guards Colonel Puzanov (1 T-34, 8 TO-34s, 4 KV-85s) liberated the towns Evpatoria, Saki, and Bakhchisaray. On 6 May 1944, once again formed into a unit, 1452nd SAP, now comprising only 1 KV-85 and 2 SU-152s, reached Sevastopol and fought in the area of Mekenziev Hills, supporting the 37th Guards Rifle Division. On 9 May the two serviceable vehicles of the regiment, a KV-85 and an SU-152, broke into Sevastopol with the 264th Guards Rifle Regiment.
The KV-85 rarely engaged enemy tanks and SP-guns during the liberation of the Crimea, and was employed primarily as a self-propelled gun for support of infantry.
The employment of the KV-85 against the German heavy tanks Pz. Kpfw VI Ausf. H occurred in the zone of combat actions of 38th Army, 4th Ukrainian Front, on 28 January 1944. During this battle Soviet tankers acted decisively and skillfully, not harboring any unfounded illusions regarding the training of the German tankers and the quality of their combat vehicles. An operations summary concerning the combat actions of armored and mechanised forces of 38th Army from 24 to 31 January 1944 to the 7th Independent Guards Heavy Tank Regiment (7th OGTTP) speaks to this. This regiment was covering the withdrawal of units of the 17th Rifle Corps, which had fallen into semi-encirclement as a result of a German counteroffensive.
"In accordance with a combat order of headquarters, 17th Corps, the remaining 5 tanks and SP-guns (3 KV-85s and 2 SU-152s) by 07:00 28.01.44 occupied all around defense at Telman sovkhoz (collective farm) and were prepared to fend off enemy tank attacks toward Rososh, Kommunar sovkhoz, and Bolshevik sovkhoz. Some 50 infantrymen and 2 antitank guns were set up in the defense around the tanks. An accumulation of enemy tanks had been spotted south of Rososh. At 11:30 the enemy launched an attack from the south on Telman sovkhoz in the direction of Rososh with up to 15 T-6 tanks and 13 medium and light tanks.
Occupying favorable positions, because of the cover provided by their fortifications and haystacks, and having permitted the enemy tanks to approach to battlesight range, our tanks and SP-guns opened fire and broke up the enemy combat formations, destroying 6 tanks (of these, 3 Tigers) and up to a platoon of infantry. The KV-85 of Senior Lieutenant Kuleshov was designated to liquidate the German infantry that penetrated our position. He fulfilled this assignment with fire and his tracks. By 13:00 of the same day the German troops had decided not to attack the Soviet position frontally, bypassed Telman sovkhoz, and surrounded the Soviet grouping.
The battle of our tanks in encirclement by superior enemy forces was characterized by the extreme skill and heroism of our tankers. A tank group (3 KV-85s and 2 SU-122s) under the command of company commander Guards Sr. Lieutenant Podust, defending Telman sovkhoz, simultaneously prevented the German forces from being shifted to other areas of battle. His tanks frequently changed firing positions and conducted well aimed fire at German tanks. The SU-122s, exposing themselves, fired at infantrymen riding in transporters and moving along the road to Ilintsa, which limited the freedom of maneuver of German tanks and infantry and, in the main, made possible the escape from encirclement of units of the 17th Rifle Corps. The tanks continued to fight in encirclement until 1930, although there were no longer any infantrymen in the sovkhoz. Maneuver and intensive fire, and as well the use of cover for conducting fire permitted them to suffer almost no losses (only 2 wounded), while inflicting significant personnel and equipment losses on the enemy. Through 28.01.44 the Germans lost (both damaged and destroyed) 5 Tiger tanks, 5 T-4 tanks, 2 T-3 tanks, 7 armored transporters, 6 antitank guns, 4 machine-gun positions, 28 wagons with horses, and up to 3 platoons of infantry.
At 20:00 the tank group broke out of encirclement and by 22:00, after a firefight, reached the position of Soviet troops, having lost 1 SU-122 (burned up)".
Countless examples of the employment of the KV-85 tank demonstrated that the 85 mm gun was an effective weapon against German heavy tanks (Panther and Tiger) and should have been mounted on the T-34 Medium Tank, which in fact it was, later. Even before the operation for the liberation of the Crimea, commanders of mobile pursuit detachments complained of the fact that the KV-85 and SU-152 were not fast enough and fell behind their infantry-carrying trucks. It was understandable, given that the KV-85 was a heavy tank. However its low maneuverability and speed was compensated for by its powerful armor and armament. And if the survivability of the KV was considered at that time to be sufficient, then the gun required significantly more power so that it could defeat German equipment at maximum ranges.
In accordance with the results of the combat actions of the KV-85, the designers and military decision makers concluded that subsequent modernisation of the KV tank family was not appropriate. While the 85 mm gun was adequate to defeat German tanks, it lagged behind German tanks in its armor-penetrating capability when fired at long ranges. Soviet heavy tanks were weaker in armor than their German counterparts. Consequently, the concept of medium and heavy tanks (T-34 and KV) armed with a cannon of a single caliber was outdated. It was necessary to have a heavy tank with a powerful gun that was superior to the German 88 mm gun in all basic parameters.
These conclusions were considered during the creation of the JS-2 tank with its 122 mm gun and during the expansion of the production of the 85 mm cannon for the T-34-85.
As concerns the KV-85, in view of their small quantity in production and intensive employment, only isolated tanks of this modification remained in the forces by the middle of 1944.
At the present time two KV tanks with the 85 mm gun have been preserved. One of them is the KV-85 mounted as a memorial in the area of Avtovo in St.Peterburg. The other is a production KV-1S armed with the 85 mm Tank Cannon S-31 in standard turret located in the Museum of Armored Vehicles at Kubinka, near Moscow.
Experimental Vehicles based on KV-85
Attempting to increase still greater the firepower of the KV tanks, and also for development of new artillery systems on a "live" tank chassis, it was suggested to mount the 100 mm Gun S-34 in the turret of a KV-85. The new vehicle was designated the KV-100. After testing, the turret of an JS-2 tank with the 122 mm Gun D-25 was mounted on the KV-85 chassis. Although no principal problems resulted from this reworking, the design was rejected because the JS-2 had already been placed in mass production.
In 1943, carrying out a personal order of J.Stalin, the artillery design bureau attempted to give a second life to the KV-2 Heavy Assault Tank, as very necessary for the destruction of enemy defenses. The primary problem in this regard was the fact that it was necessary to mount the 152 mm howitzer in a standard turret of the KV-1S. The TsAKB and OKB #9 were engaged in secret competition for the development of this artillery system. Both collectives drew the conclusion regarding the principal necessity of using a high-efficiency muzzle brake in the construction of their gun. OKB #9 already had a recommendation for adopting the 152 mm Field Howitzer D-1 as standard. Therefore, during the creation of a tank variant, its recoil components were carried over to the carriage of the D-5T tank gun. Thus far no significant proof has been found that the D-1-5 (or D-15) howitzer was mounted even on a single KV, but an SP-gun on the T-34 chassis with armament from the "152 mm Tank Cannon D-1-5" had been considered for some time as a future variant to replace the SU-122.
The TsAKB took a slightly different path. Here they preserved the designs of the ZIS-5 and S-31 guns, but somewhat strengthened them. Production proceeded without problems and a KV with an S-41 152 mm howitzer was demonstrated to Marshal Voroshilov during his visit to the TsAKB in August 1943. Unfortunately, no additional details are known about this vehicle.
In view of their futility, all experiments with 152 mm howitzers in tank turrets were halted by order of the NKV in October 1943. The SU-152 already was slated for fielding and work was being conducted on the creation of the JS-122 (JS-2).
Sources: "M-Hobby", #1, 2000 I.V.Pavlov M.V.Pavlov "Sovetskie Tanki i SAU 1939-1945", Moscow 1996 M.Svirin "Artillerijskoye Vooruzhenie Sovetskikh Tankov 1940-1945", Armada Vertikal #4 "KV - Sovetskij Tyazhelij Tank", Tornado, Riga 2000.