IS-3: THE LAST BREAKTHROUGH TANKDrafting of a new heavy tank, much superior to commercially produced is-2 on armor protection began in accordance with the decree of GKO No. 5583 on 8 April 1944 and had its prehistory. A group of researchers of the Military Academy of mechanization and motorization in the name of Stalin, led by engineer-Colonel A. Zavialov studied in the field of tank battles the battle of Kursk, the nature of the damage caused by the shells hitting tanks. It turned out that not all parts of the tower and was amazed the same: more suffering frontal part, while the number of hits in the tower was the greatest. The result of these studies and was the project of a new tank.

All project work was conducted in the conditions of tough competition between the two design teams — Experienced factory number 100, organized in March 1942, and headed by J. Y. Kotin and A. C. Ermolaev, seeking to confirm its leadership in the development of heavy tanks, and the design Bureau of the Chelyabinsk Kirov plant, headed by N. L.Brass and M. F. Bali, hoping to show their maturity and independence.
The main feature of the project proposed by the Chelyabinsk factory were the original flattened tower with 122 mm gun D-25, developed by designer G. V. twisted. Large angles of inclination of the armored walls of the tower contributed to the ricochet armor-piercing shells, and a good internal layout provided the minimum sizes allowed without unnecessary weight machines to increase the thickness of the frontal armor up to 250 mm vs 100 mm on a heavy tank is-2.
J. Kotin has prepared its own version, based on the development of a pilot plant for the objects 244, 245 and 248, which immediately caught the eye was the unusual shape of the bow of the hull. The fact that almost all the tanks of that period the upper frontal part of the welded and cast hulls was a surface perpendicular to the longitudinal plane or at a slight angle to the vertical. This form was required, while in front of the tank were two men. With the exception of the crew of radioman, when there were single driver, besides planted in the center, the opportunity to cut corners on the face plate. So, the JS-2 in die-cast front part there was “cheek”. It became possible not only to reduce the weight of the body, but also greatly enhance the durability of the armor parts in case of fire tank in the front. The designers of the pilot plant G. N. Moskvin and V. I. Teotico offered to make the entire upper frontal part of the body of two connected and strongly inclined to the vertical plane of the armor plates that rotated in terms of at a large angle. On top of these leaves were covered with a triangular roof, inclined to the horizon at an angle of 7°. In the roof directly overhead of the driver there was a hatch through which he could get into the tank and leave it. Such a saddle nose received from the designers called “aquiline nose” (though more the name stuck “pike nose”).
The transition to a fully welded hull with the exception of large castings was due, on the one hand, the achievements of welders headed by academician E. O. Paton, on the other — the capability of the foundry, which was fully loaded by the production of cast towers for tanks is-2.
Heavy tank is-3
Heavy tank is-3
Heavy tank is-3:
1 — 122-mm gun; 2 — eye tower; 3 — surveillance device gunner; 4 — a DShK machine gun; 5 — turret; 6 — external fuel tank; 7 — driving wheel; 8 — support roller; 9 — cleaner drive wheel; 10—supporting the rink; 11 — emphasis equaliser; 12 — Trak tracks; 13 — surveillance device loader; 14 — a cover of the hatch door; 15 — surveillance device commander; 16 — earrings for samovets-nodding; 17 — antenna input; the 18 — gun mask; 19 — mount the gun in its stowed position; 20—spare tracks. On the top view DShK conventionally not shown. All detailing done in scale M1:25
October 28, 1944, the first model of a new tank ChKZ came out of the factory and underwent sea trials on Brodokalmakskogo tract. During the run revealed oil leak from the gearbox, and the car returned to the shop. In November alone, this tank was made at the factory of 1,000-km tests, which again failed. Designers and technologists ChKZ became clear that the planned changes could significantly hamper the serial production and further operation of the tank. Therefore, we decided to abandon the engine-11 with a power of 620 HP, greatly overstressed the drivetrain and not to change the existing design of the chassis, powerplant and drivetrain of the tank is-2, limited only by improving the armor protection.
25 November 1944 ChKZ produced a second prototype that military acceptance was named “Sample a” And the plant — “Kirovets-1”. Soon, in accordance with the order of the commander of BT and MV KA he received the official name “heavy tank is-3 (sample No. 1)”.
After the completion of the factory test tank was sent to Netpolice to pass state tests, kotoryu was conducted from 18 to 24 December. Then he was examined by the Deputy commander of armored and mechanized troops of the red Army, Marshal of armored troops P. A. Rotmistrov. He walked around the car from all sides, went upstairs, climbed inside the tank, sat on the seat of the driver and, after hearing a detailed report of chief engineer of the machine M. F. Bali, said:
This car needs the army!
At the same time, the pilot plant number 100 and CRI-48 was introduced in NKTP your project of modernization of armor protection of the is-2. In this regard, the Moscow branch of the TSNII-48 conducted a comparative analysis of the two projects and came to the conclusion that the best solution of the question of strengthening the armor of the tank is-2 is the creation of this design, which will maximize the use of the advantages of both options. In particular, the new armour protection of the tank could turn on the forward part of the type proposed by the plant number 100 and TSNII-48 (saddle-nose); the bottom of the case — the embodiment of the Chelyabinsk Kirov plant (trough); in the cross section of the tower could be used a principle proposed by ChKZ (a domed form), and in horizontal sections — towers of the plant number 100 and TSNII-48 (cross section approaching an ellipse).
Approximate calculations showed that when using these suggestions you can create (within weight of the tank indicated the Kirov factory and factory # 100) this design of armor, which would reduce the likelihood of penetration of the hull when firing 88-mm shells to 34% against 39,5% in case of factory No. 100 — CNII-48, and 44.1% in case of the Kirov factory.
For consideration by the people’s Commissar for tank industry V. A. Malyshev received two independent project, two versions of the same tank. The first was represented by the Director of the Chelyabinsk Kirov plant, I. M. Saltzman and chief designer N. L.Spirits, the second a Director and the chief designer of a pilot plant J. Kotin. Having considered the projects and taking into account the recommendation of the TSNII-48, V. A. Malyshev issued order No. 729 dated 16 December 1944, which defined the further course of works on creation of the tank. The car has already been officially assigned the index of “Kirovets-1” was approved the schedule of works and determine the volume of an experimental batch of 10 pieces. And 8 of them needed to collect by January 25, 1945.
Thus was born a new model of tank breakthrough — the fruit of joint efforts of two Kirov design team, split, are, in principle, impossible. Before the formation of the pilot plant the main part of the designers worked in the state and in the territory of the Chelyabinsk Kirov plant, and only later were partially redesigned pilot plant. However, this part mostly stayed and worked at the main plant, to carry on the design and production task at the Chelyabinsk Kirov plant.
In the work calendar of the Director of the Chelyabinsk Kirov plant, I. M. Zaltsman, where he marked the implementation of the work schedule, the new machine went under the name “Victory”. But no matter how he wanted to give “his” car with a loud name, the tank went into production under a familiar name — is-3. The only thing that made serial the plant, so that the object room the tank was rated at the Chelyabinsk Kirov plant — the object 703.
The bottom of the case
The bottom of the case:
1 — the emergency exit; 2 — tube holes for water drainage; 3 — cover under engine hatch; 4 — cover flap to drain the fuel from the left tanks; 5 — cover under the trip mechanism of the main clutch; 6 — tube holes to drain the oil from PMP; 7 — tube drain oil from gearbox; 8 — cover flap to drain the oil from the oil tank and fuel from the right tanks; 9—armored box of the boiler heater; 10—the plug of the exhaust gas discharge lamp heater
On 12 February 1945 at the Chelyabinsk Kirov plant has completed Assembly of the two sections of the tank is-3 (#2 and # 3), who were sent to NIIBT testing ground for attack. And the first is-3 20 Feb brought the military Department and sent to Moscow. His field tests were conducted from 23 March to 11 April in Kubinka. After the test, the tank was submitted to G. K. Zhukov and A. M. Vasilevsky. The marshals reported on the new machine to Stalin, who signed the decision of GKO No. 7950сс on the adoption of the tank for red Army use and production at the Chelyabinsk Kirov plant. On 21 may, the head of the Technical Department of gbtu of the red Army A. I. Blagonravov signed the order “On approval of technical documentation for tank is-3”. On may 24, were collected 29 tanks is-3, of which only 17 passed the manufacturer’s tests.
Heavy tank is-3 (object 703) was very sophisticated for its time, the shape of the hull and turret with a large thick armor plates. Frontal hull plates were installed in the form of “pike nose” with dual tilt at a large angle to the vertical. The top of the Board was given a reverse slope to fit a wide turret. Sloped armor plates in the junction of the sides and bottom has reduced the total area of the surface of the body and due to the saved weight to strengthen the body armor. The aft hull for ease of access to the units of the power transmission made folding.
The driver was located ahead of the axis of the machine. Above his seat there was a hatch with sliding to the side cover, which mounted viewing device. Before opening the hatch it was necessary to remove. Behind the driver’s seat, in the bottom, placed a spare hatch.
Cast tower had a flattened spherical shape. In the roof of the tower was a large oval hatch, lockable two covers. In the right cover was raised viewing device charging — MK-4; the left housed the commander’s hatch of observation, round rotating lid, which was mounted viewing device commander’s TPK-1.
This device is intended for surveillance of the terrain, determining the range to target, target acquisition and artillery fire adjustment. Developed commander’s turret of the tank had. Another device MK-4, gunner, mounted in the top of the tower, to the left in the course.
The rotation mechanism of the tower — planetary, with manual and electric stepless drives. The actuator was equipped with the system commander control. The commander could, keeping the target in sight of your viewing device, click on application installed on the device, and rotate the turret in a given direction along the shortest path. When the coincidence of the line of sight with the axis of the bore tower stayed. The maximum speed of rotation of the tower stood at 12 deg./C.
122-mm tank gun D-25T mod. 1943 with a barrel length of 48 calibres and coaxial 7.62-mm DT machine-gun was installed in a molded mask. The gun is supplied with two-chamber muzzle brake and horizontal wedge gate with semi-automatic mechanical type. The initial velocity armor-piercing projectile was equal to 781 m/s Sighting range (with the use of a telescopic sight TSH-17) 5,000 m, and the side of the level to 15 000 m Rate of fire 2-3 RDS./min.
On the turret roof on the turret was the anti-aircraft 12.7-mm machine gun DShK.
Gun ammunition consisted of 28 rounds of separate loading ammunition, including: 18 — with high-explosive shells and 10 with armour piercing. It should be noted that to facilitate the orientation of the loader all the styling, designed to accommodate armor-piercing shells, was painted in black color and the rest in steel gray.
Ammunition for the machine guns DT consisted of 945 of the cartridges equipped in 15 stores, for DShK — 5 belts of 50 rounds, each of which was Packed in a separate box. One box was mounted on the gun, the rest were placed in the fighting compartment.
Four-stroke twelve-cylinder V-shaped diesel engine-11-is-3 liquid-cooled with a displacement of 38 880 cm3 and maximum power of 520 HP (382,5 kW) at 2200 rpm was installed on the brackets welded to the side sheets of the housing.
Cover of the driver's hatch
Cover of the driver’s hatch:
1 — hatch cover; 2 — Cup holder; 3 — spring; 4 — bracket; 5 — roller; 6 — the profile of the Cam; 7 — fixator; 8 — arm rotation lid; 9— axis of the hatch cover; 10 — guide bushing; 11 — ring retainer; 12 — arm; 13 — a rubber band; 14 — bolt; 15 — bracket; 16 — folding handle
In the fuel tank system consisted of four internal tanks with a total capacity of 450 litres, are placed two on each side of the engine. Four external cylindrical tank with a capacity of 90 liters each mounted on the inclined hull plates on the sides aft and connected to the inner. Tanks have a mechanical device to reset (latches with cable management). Reset arm mounted on the sides of the rear of the fighting compartment.
Power transmission — mechanical. The main clutch — multiplate dry (steel albomaculata). Transmission (KP) — vosmichastny, with dual. Planetary rotation mechanisms, a two —stage, located at the ends of the main shaft KP. Lock-up clutches PMP — multi-disc, dry (steel on steel). Brakes floating, belt (iron steel). Airborne transmission — reducing gearboxes with simple gear and planetary.
The driving wheels had removable rims with 14 teeth. Guide wheel was interchangeable with the road wheels. The mechanism for track tensioning screw, crank.
On each side there were six support dual and three track-return rollers. Suspension rollers — individual, torsion. Caterpillar — small-Sonata, cycloid gearing. The nominal number of tracks in each track — 86, the minimum 79. The connection of the Shoe — open hinge. Step Trak— 160 mm, width — 650 mm. the Truck was a casting or a shaped stamping.
The tank was installed radio 10-RK-26 and tank intercom TPU-4бисФ.
As mentioned above, the first batch of heavy tanks is-3 left the factory shop at the end of may 1945. In the fighting of the great Patriotic war and war with Japan, they did not participate.
The first demonstration of these combat vehicles of world public opinion took place only on 7 September 1945 in Berlin during the parade of allied troops in honor of the end of world war II.
The parade was commander of the Soviet occupying forces, Marshal Zhukov, commander of the 3rd U.S. army General George Patton, British General Robertson and French — Koenig. Also present were a large number of the higher ranks, both Soviet and allied troops. The parade was opened by Hiking columns: before the General’s podium, marched the infantry of the 9th infantry corps of the 5th Soviet shock army, followed by soldiers of the 2nd French division of infantry, Alpini and the zouaves, flashed bearing 131st infantry brigade English. Closes foot structure one thousand paratroopers of the 82nd American airborne division. After a short break the audience was approaching mechanized column, which opened 32 light tanks M24 “General Chaffee” and 16 armored cars M8 from us 705 th tank battalion, behind them were tanks and armored vehicles of the French 1st armored division. The British put on parade 24 tanks “Comet” and 30 armored vehicles of the 7th armored division. Finally, at the conclusion of the parade Charlottenburgh highway 52 were tank is-3. Consolidated tank regiment was formed on the basis of the 71st guards heavy tank regiment of the 2nd guards tank army. The new Soviet heavy tanks made a shock impression on our Western allies.
For the first time at the parade in Moscow, the new tanks were shown on 7 November 1946.
The is-3 tank was in mass production until mid-1946 (in may 1945 some time — together with is-2).
Published a total of 2311 tanks.
Is-3 was armed with a heavy tank-self-propelled regiments of the Soviet Army. Baptism of fire of these machines in the Soviet Army took place in 1956 in Hungary. However, several tanks were lost.
However, in the very beginning of their operation in the military revealed a number of shortcomings resulting from a number of design miscalculations and mistakes made in its design. Therefore, in 1946, established a Commission for the analysis of defects is-3, which include failure of the engine, transmission, elements of hulls in the area of the engine compartment, etc.
В1948—1952 all tanks is-3 was subjected to modernization and alterations program ukn (elimination of design flaws). Were reinforced mounting brackets of the engine, modified the mount, manual, reinforced turret sheet, improved design of the main clutch, improved seals, final drives and track rollers. Instead of manual hydraulic oil fill pump an electric. Radio 10-RK replaced by 10-RT. The weight of the tank has increased to 48.8 T. Despite the significant amount of rework and the high cost (ukn program for one tank cost 260 000) tanks have not been brought to the required level of operating requirements.
In the late 1950-ies, the tank has undergone additional modernisation and became known as the is-ZM. The aim of the upgrade was removing it at the level of the combat vehicles of the period and the maximum standardization of units and assemblies with a more modern tanks. The design of the tank made the following changes and additions: increased body rigidity by the insertion of slats in the rear sheet and the braces to the bottom; in the bottom of the CP cut-out hole and closed the lid, welded overlapping, to increase the gap between the KP and the bottom; the DShK replaced by the modernized DSHKM, and machine gun DT — DTM; sealed by rotating the cap commander’s hatch; installed night vision device TVN-2 driver; is In-11-is-3 is equipped with the engine V-54K-is the maximum power of 520 HP air Cleaners of the type “multi-cyclone” is replaced by VTI-2 with two degrees of cleaning and seek-tional removal of dust from the first stage. In the lubrication system mounting the new oil tank with heat exchanger and defoaming agent. The cooling system integrated heater KNICKS-1 with electric; aft provided for mounting two 200-liter fuel drums; reinforced bearing assemblies track rollers and idlers, modified seals; in the electrical system introduced two-wire circuit or emergency lighting. Aft mounted receptacle external trigger. On some of the tanks were removed, the system commander control. Instrumentation direct action replaced electric; set of radio station R-113 and tank intercom R-120.
It should be emphasized that the modernization greatly increased the reliability of the tank. However, the age of it has already been meted out. After the modernization of the tanks were heading to parks, where it was placed on long-term storage.
The manhole cover of the tower
Manhole cover of the tower:
1 — torsion cushions; 2 — observation instrument the commander of the tank; 3 — commander’s hatch cover monitoring; 4 grips; 5 — copy the device commanding the control tower; 6 — left manhole cover of the tower; 7 — right manhole cover of the tower; 8 — lever; 9 — viewing device charging; 10— grip mount turrets anti-aircraft guns
In 1946, two tanks gave Poland to familiarize with the design and training of trainers. Apparently, the anticipated adoption of it on Board of the Polish army. In the 1950-ies both machines several times participated in military parades. Subsequently, until the early 1970s, one machine was in the military technical Academy in Warsaw, and then was used as a target on one of the polygons. The second is-3 was more fortunate — it was handed over to the Higher officer school of armored troops imeni S. Czarnecki, the Museum where it is stored until now. In 1950 a tank is-3 with a similar evaluation test target was transferred to Czechoslovakia.
Much more tanks is-3 sent to North Korea (after Korean war). In the 1960-ies in the two North Korean tank divisions had one regiment of heavy tanks.
The Egyptian army received the first tanks is-3 in the mid 1950-ies. 23 July 1956 they took part in the parade in honor of independence Day in Cairo. The majority of the 100 IP-3 and IP-GP, delivered to Egypt, and came to this country in 1962-1967, respectively.
5 June 1967 Israeli forces went on the offensive in the Sinai Peninsula — the war began, called the “six day”. A crucial role in the operations on the land front, played armored and mechanized formations, the basis of the Park which is on the Israeli side was М48А2 American tanks with 90-mm guns, the British centurion Mk5 and Mk7, upgraded in Israel by mounting the 105 mm gun and upgraded tanks M4 “Sherman” with a French 105 mm guns. On the Egyptian side they were opposed by tanks of the Soviet production of the T-34-85, T-54, T-55 and IP-3. The latter, in particular, were part of the 7th infantry division, who held the defense at the turn of the Khan Yunis — Rafah. 60 the is-3 was the 125th tank brigade, the positions of which were near El-Kuntilla.
Heavy tanks of the Soviet production (as, indeed, all others) could become a serious threat to Israelis. However, this has not happened, although several M48 were hit. In conditions of highly maneuverable combat is-3 was lost to more modern tanks of the Israelis. Impact low rate of fire, limited ammunition and hopelessly outdated fire control system (for comparison — in М48А2 stood riflescope-rangefinder and two-axis stabilizer guidance). Poorly adapted to work in a hot climate was the engine of the is-3. But most importantly — military training Egyptian tankmen was much lower than Israel. Affected by the low educational level of the main mass of personnel hindered the development of military equipment. Low was the morale and fighting spirit of soldiers did not show the necessary firmness and tenacity.
The latter circumstance is well illustrated by the unique from the point of view of a tank battle, but typical of the “six day war” episode. One IP-GP was hit in the Rafah area, a hand grenade, accidentally flew into the… open the turret hatch. Egyptian tanks went into battle with open hatches, to be able faster to leave the tank in the event of a defeat.
Soldiers of the 125th tank brigade, retreating, simply abandoned their tanks, including the IP-GP, which fell to the Israelites in absolutely good condition. In the end, the Egyptian army lost 73 tanks is-3 and is-ZM. By 1973, she had only one tank regiment of combat vehicles. Data about his involvement in the fighting there.
The IDF used captured IP-GP until the early 1970-ies. At the same time worn engine V-54K-is replaced by the In-54 from captured tanks T-54A. At the same time, the last borrowed and the roof of the engine compartment. To the Arab-Israeli war of 1973, the majority of IP-ZM was set as fixed emplacements dug into the ground along the Suez canal. In the course of fighting any significant role they played and again fell into the hands of the Egyptians.
This exhausted by a single full episode of the combat use of the fate of heavy tank is-3.
In their tactical and technical characteristics of the is-3 definitely surpassed its predecessor — tank is-2. Very flattering assessment “is the third” found and abroad. According to the West German expert Dr. Von senger und Etterlin, “rational design of the bow of the hull and turret is highly commendable. In addition, this tank has a very small height. For 1956 the is-3 tank reserves the best for heavy machine, the combination of fighting qualities”.
However, these structural defects negatively affected the combat capabilities of the tank. Despite the implementation of two programs of modernization, to eliminate them completely failed.

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