Thursday, October 30, 2014

Some Info on the IS-2U Designs

In 1944 an informal competition began to develop between the ChKZ and Factory №100 to improve the armor protection of the IS-2. Two solutions were presented to solve this problem,  P.P. Isakov suggested that the front hull be comprised of a downward pointing wedge. The sides would not be vertical like other tanks instead the sides would slope upwards. The bottom of the hull would be flat and instead would be sloped upwards as well. This design would've require removing the torsion bars and placing ribs along side the hull for bogies that would be used for the spring suspension. This solution also did not leave adequate room for ammunition and fuel.

G.N. Moskvin suggested that part of the hull remain vertical and that floor remain flat. This solution did not require abandoning torsion bar suspension. The fuel would stored in between sheets of armor at the bottom of the tank. However this complexes welding and is not consistent with the all wedge hull that was originally envisioned. However G.N. Moskvin was replaced by S.V. Mickevich and worked further on his solution.

The IS-2U in its final form

Sunday, October 26, 2014

The Object 142

In the 2nd half of 1957 at the suggestion of Chief the Armored troops of the Soviet Army Colonel General P.P. Poluboyarova suggested that a new tank be developed on the basis of the Object 140 but uses the chassis of the T-54B to ensure maximum part compatibly. The tank was designed at factory №183 under the leadership of Leonid Karcev. One prototype was built and underwent testing in the fall of 1958.

The Object 142 was armed with the 100mm D-54TS. The tank contained 50 rounds of ammunition for the main gun. The D-54TS was two plane stabilized with the “Blizzard” stabilizer. The gun was aimed with a TSH2A telescopic sight while night sighting was used with the TPN-1. Gun traverse of the main gun was -5 to 16 degrees. Unlike the Object 140 the Object 142 lacked a mechanism for spent shell ejection. Due to removing the AA gun that was on the Object 140 spaced was freed up for more ammunition (3,500 rounds) for the 7.62mm SGMT machine gun. The armor layout was mostly the same as the Object 140.

The Object 142 was powered by the 580hp B-55. Top speed was 50km/h. The transmission was essentially that of the T-54B. Most of the parts from the Object 142 power system were taken from the Object 140 except for the heater and fuel tanks. The Object 142 carried 715 liters of fuel plus 285 on external tanks. This gave the Object 142 a range of 500km.
Armor layout of the Object 142
 The Object 142 was canceled with the start the start of production of the T-55 at Factory №183 and research being undertaken to improve the fighting capability of the T-55.While the Object 142 was short lived it did form the basis for the T-62A and thus the T-62. The Object 142 would mark the start of Nizhny Tagil's move to improve tank capability of it's future tanks with older ones. It should be noted that the Object 142 is commonly misidentified as the T-62A, you can tell the difference by seeing if it has a Object 142 turret and hull.

Sunday, October 5, 2014

Soviet Tank Production 1945-1965

The Soviets built a lot of tanks from 1945 to 1965, this chart from Отечественные бронированные машины 1945-1965 shows us how much they built and what they did build.

The T-62A

What was to become the T-62A was born in January 1959. It was developed by Nizhny Tagil with L.N. Karcev as the head designer. By October two prototypes were built and from November 4th 1959 to April 14th 1960 underwent factory testing. During that time it underwent running test that totaled 4,000km and underwent testing firing at the Ural Artillery Range. After firing against the tank's hull and turret at the NIIBT testing ground in January 1960 the plans for the tank were finalized. In December of 1960 the T-62A passed state testing. However it was not until August 9th 1961 that the U-8TS was not approved as the tank's main armament. On January 9th by Decree of Ministry of Defense of the USSR №7 the Object 165(the T-62A's GABTU designation) was accepted into service under the name T-62A. However it was not until October 1962 by decree of the Central Committee of the CPSU and the Council of Ministers of the USSR №1096-460 that T-62A was put into production. However by next year by decree of the Council of Ministers of the USSR №2235-pc further production and work on the T-62A was stopped due to lack of improvement in the APDS ammunition and stabilizer. Plant №183 was only able to produce 5 units during this time.

The T-62A was rather conventional tank, which is no surprised as it was based off the T-55 and Object 142 tank. However the gun itself was the main attraction, the T-62A was armed with the U-8TS which fired a APDS round at 1535m/s which enabled it to penetrate 310mm at 1000 meters. Unlike other Soviet tanks it had good gun depression with -7 to 16 degrees of gun traverse. There were 43 rounds of ammunition for main gun, along with 3,000 rounds for the two 7.62mm machine guns. The ammunition composition was 40% APDS, 40% HE and the remaining 20% HEAT. It had average fire control with the gun being aimed through a TSH2A telescopic sight. It was stabilized the "Comet" stabilizer which was based off the "Downpour" stabilizer on the T-10M. A novel feature of the T-62A was the mechanism to remove spent shells from a hatch at the back of the turret. This was implemented to reduce fumes in the fighting compartment. 

The armor protection was mostly the same as the T-55 on which the T-62A based; however the turret had increased armor protection compared to the T-55.  The hull of the T-62A itself is increased by 386mm. Parts of the bottom hull were reduced from 20mm to 16mm to save on weight. 

The T-62A had comparable mobility to the T-55 of which it was designed to replace; the 580hp V-55V gave the T-62A a top speed of 50km/h. The average speed on paved road was 26.6km/h to 34.2km/h and on dirt road it was 19.8km/h and 24.8km/h. The T-62A contained 680 liters of fuel(plus an optional external 280 liters) which gave it 500km of range.

The T-62A was an evolutionary step in the design of Soviet medium tanks; while it did not have many revolutionary features it did present a dangerous threat to its NATO competitors. However the Soviets quickly realized in the production of the T-62A that APDS was a dead end compared to APDSFS and so the T-62A was overshadowed by its more numerous brother the T-62. Despite its short life the T-62A did influence Soviet tank design in a big way. The T-62A formed the basis for what would be become the T-62 and it would also provide the impetus for A.A. Morozov to design the T-64.

Saturday, October 4, 2014

Penetration of Various Guns

The Soviets made a lot tank guns during the post war period. Some were very powerful, here are some penetration tables from ОТЕЧЕСТВЕННЫЕ БРОНИРОВАННЫЕ МАШИНЫ 1945-1965 гг. of a few of them:

These guns were mounted on the PT-85 and PT-90

The Object 141

The development of the Object 141 began on September 12th 1952 by decree of the Council of Ministers of the USSR №4169-163. The design of the tank was headed by A.V. Kolesnikova. In July 1953 Factory №183 produced a full sized wooden mockup. The 100mm D-54(which was designed by F.F. Petrov) was not received until March 1954. It was not until January 1955 that a prototype underwent test firing at the Rzhevka artillery range in Leningrad. Testing continued until November 1955 when it was halted to revise the stabilizer, after testing in the summer of 1956 further work on the stabilizer was stopped to due to the satisfaction with the stabilizer.

The point of the Object 141 was to mount the new 100mm D-54. Because of this the Object 141 only differed from the T-54 model 1954 in only the gun and minor changes in the turret to accommodate the gun. The gun was powerful, it fired a 16.1kg shell(total weight of the round is 33.8kg) which enabled the D-54 to penetrate 240mm at 1000(or 85mm at 60 degrees from vertical) meters. The D-54 was aimed by a TSH-22A telescopic sight and was stabilized by the "Rainbow" stabilizer. The increased power of the D-54 did not come without cost however, the weight of the gun was 2515kg vs the 1950kg of the D-10T. This increased the weight of the tank to 36.6 tons and lowered the tank's top speed to 48km/h. Due to the length of the one piece ammunition(1060mm) the Object 141 only contained 28 rounds of ammunition.

The 100mm D-54 from the Object 141

During testing on the NIIBT testing ground in late 1958 it was suggested by Factory №183 to increase the range of the tank to mount three 100 liter fuel tanks. After testing it was revealed that fuel tanks did not interfere with the firing angles of neither the main cannon nor the 12.7mm AA gun. However the increase in range that the fuel tanks offered was not deemed necessary.
The external fuel tanks mounted on the Object 141

In February 1959 the Object 141 was sent to Factory №183 and in March the D-54 was replaced with the smoothbore 115mm U-5B(also designed by F.F. Petrov) which was designed for use in the Object 166 tank destroyer. During tests held from April to June the accuracy of the U-5B was found to be unsatisfactory compared to a U-5B on a ML-20 carriage. The reasons were mainly due to the fact that gunner was not inside the tank due to safety reasons and the imperfections in the early APDSFS ammunition.

The Object 141 had a long life; however it was quickly obsoleted by the more modern Object 140, Object 139, and Object 165. The Object 141 did mount the new D-54 which later be mounted on the T-62A and would form the basis of the U-5TS on the T-62. Unlike other Soviet tanks the Object 141 was not cancelled outright, it faded away.

The Object 141 as represented in World of Tanks


Hello and welcome to my blog. I will be discussing post war Soviet tanks such as the IS-7 and other tank related developments made by the Soviets immediately after the war.