Editing T-72 (section)

==Development==
===Development from the T-64===
The T-72 was a product of a rivalry between design teams. [[Kharkiv Morozov Machine Building Design Bureau|Morozov KB]] was led by [[Alexander Alexandrovich Morozov|Alexander Morozov]] in [[Kharkiv]]. [[Uralvagonzavod|Uralvagon KB]] was led by [[Leonid Kartsev]] in [[Nizhny Tagil]].{{sfn|Zaloga|1993|p=1-18}}

To improve on the [[T-62]], two designs based on the tank were tested in 1964: Nizhny Tagil's Object 167 (T-62B) and Kharkiv's Object 434.{{sfn|Zaloga|1993|p=1-18}}

Ob. 434 was a technically ambitious prototype. Under the direction of Morozov in Kharkiv, a new design emerged with the hull reduced to the minimum size possible. To do this, the crew was reduced to three soldiers, removing the loader by introducing an automated loading system.{{sfn|Ustyantsev|Kolmakov|2004|p=38}}

Ob. 167 was designed based on an [[Object 140]] rebuilt by Kartsev and Valeri Venediktov. Ob. 167 was more advanced than Kartsev's Ob. 165 and Ob. 166, and was also Kartsev's favored model. In October 1961, when asked to ready Ob. 166 for production, Kartsev disagreed and instead offered to prepare the Ob. 167. This suggestion was rejected, and the Ob. 166 and Ob. 165 were readied as the T-62 and T-62A respectively. Unlike the Kharkiv tank, it eschewed the state-of-the-art prototypes and used the turret from the T-62, and a manual loader. In 1964, the tank underwent comparative testing with the Ob. 434, in which the former proved its superiority to both the T-62 and [[T-55]]. Ob. 167 was favored by Uralvagonzavod director I.V. Okunev and Soviet Premier [[Nikita Khrushchev]], who believed the tank was more affordable. [[Deputy Chairman of the Council of Ministers of the Soviet Union]] [[Dmitry Ustinov]], believed the parallel development of Ob. 167 jeopardized the future of the Kharkiv tank. In December 1962, the [[Council of Ministers of the Soviet Union]] ordered Ob. 432 (later serialized as the [[T-64]]) into production, dooming Kartsev's tank.<ref name="Kinnear">{{cite book |last1=Kinnear |first1=James |last2=Sewell |first2=Stephen L. |year=2001 |title=Soviet T-62 Main Battle Tank |publisher=Osprey Publishing |isbn=1-47284-822-5}}</ref>

Kartsev continued to work on the Ob. 167. Ob. 167M incorporated an [[autoloader]]. This model too was rejected in May 1964.<ref name="Kinnear"/>

Problems with the early production run were evident from the start, but a strong lobby formed around Morozov who advocated for Ob. 434 in Moscow, preventing rival developments and ideas from being discussed.{{sfn|Ustyantsev|Kolmakov|2004|p=53}} Ob. 434 was accepted into Soviet Army service in May 1968 as the T-64A.{{sfn|Zaloga|2015|p=22}}

The T-64's smaller design presented a problem when selecting a suitable engine.{{sfn|Ustyantsev|Kolmakov|2004|p=30}} The chosen 700&nbsp;hp 5TDF engine was unreliable,{{sfn|Zaloga|2009a|p=16}} difficult to repair, and had a guaranteed lifespan similar to [[World War II]] designs.{{sfn|Ustyantsev|Kolmakov|2004|p=35}}

===Object 172===
In 1967, the Uralvagonzavod formed "Section 520", which was to prepare the serial production of the T-64 for 1970.{{sfn|Ustyantsev|Kolmakov|2004|p=32, 36}} Because of the time-consuming construction of the 5TDF engines, which took about twice as long as the contemporary V-45, the [[Malyshev Factory]] in Kharkiv could not provide a sufficient number of 5TDF engines for all Soviet tank factories.{{sfn|Ustyantsev|Kolmakov|2004|p=39, 40}} The [[Military-Industrial Commission of the USSR|Military-Industrial Commission]] (VPK) authorized work on two alternative engines for a wartime T-64, a so-called "mobilization model" that could be produced more quickly and at half the cost.{{sfn|Zaloga|1993|p=1-18}} Obj. 219 (which became the [[T-80]], with a GTD-1000T gas-turbine) was designed in Leningrad. Ob. 439 with a diesel V-45 engine was designed by Uralvagon KB at Uralvagonzavod in Nizhny Tagil.{{sfn|Zaloga|2015|p=32-33, 38, 40}}

[[File:Object 172 (T-72 prototype on the basis of T-64).jpg|thumb|left|Object 172 at the [[Kubinka Tank Museum]]]]

[[Main Agency of Automobiles and Tanks of the Ministry of Defense of the Russian Federation|GABTU]] sent a T-64A prototype with a team to Uralvagonzavod. Kartsev was to lead this team.{{sfn|Sewell|1998|p=28}}

Kartsev was unsatisfied with the innovations of the T-64, and began instead a more comprehensive project to redesign the tank. Kartsev melded what he believed were the best aspects of the T-64A, Object 167, and an upgunned T-62.{{sfn|Sewell|1998|p=28}}

During development the tank was code-named "Ural" after the [[Ural Mountains|Ural mountain region]].{{sfn|Zaloga|1993|p=1-18}} Uralvagonzavod produced the first prototype with a T-62 turret, D-81 125-mm gun and V-45 engine in January 1968. Ob. 439 differed so greatly from the T-64 that it was redesignated as "Object&nbsp;172".{{sfn|Zaloga|2015|p=32-33, 38, 40}}

Kartsev's defiance angered GABTU, which initially reprimanded him for his insubordination. However, after the tank proved indeed to possess potential as a less costly alternative to the T-64, Kartsev was allowed to continue work on his design. Politically motivated opposition continued to beset the tank throughout its development. Vagonka tank plant manager I.F. Krutyakov sought to subordinate Uralvagonzavod under [[Josef Kotin]]. Kartsev skillfully beat back this play for power, embarrassing Krutyakov in the process. Kartsev retired in August 1969, and was succeeded by Venediktov.{{sfn|Sewell|1998|p=28}}

The team soon found out that the more powerful V-45 engine put a lot of stress on the T-64 hull, so that after some time cracks started to materialize. A more stable solution was sought.{{sfn|Ustyantsev|Kolmakov|2004|p=39, 40}}

Finally, an idea from 1960 was used, when a modification of the T-62 had been discussed: In 1961, two prototypes of "Object&nbsp;167" had been built by Uralvagonzavod to test a stronger hull and running gear combination for that tank. Under influence from Kharkiv, the idea had been turned down by Moscow.{{sfn|Ustyantsev|Kolmakov|2004|p=45, 46}} But this construction, with its big, rubbercoated roadwheels now formed the basis for the mobilisation model of the T-64.{{sfn|Suvorov|1993|p=4}}

Additional changes were made to the automatic loading system, which also was taken from an earlier project, originally intended for a T-62 upgrade. [[125 mm smoothbore ammunition|The 125 mm ammunition]], consisting of a separate projectile and a propellant charge, was now stored horizontally on two levels, not vertically on one level as in the T-64.{{sfn|Ustyantsev|Kolmakov|2004|p=51}} It was said to be more reliable than the T-64 autoloader.{{sfn|Suvorov|1993|p=4}} In 1964, two 125-mm guns of the D-81 type had been used to evaluate their installation in to the T-62, so the Ural plant was ready to adopt the 125&nbsp;mm calibre for the T-64A as well.{{sfn|Ustyantsev|Kolmakov|2004|p=52}}

Venediktov's team later replaced the T-64-style suspension with the Obj. 167's suspension. The tank was trialed in [[Kubinka]] in 1968, and Central Asia in 1969.{{sfn|Zaloga|1993|p=1-18}} After intensive comparative testing with the T-64A, Object&nbsp;172 was re-engineered in 1970 to deal with some minor problems.{{sfn|Ustyantsev|Kolmakov|2004|p=56}} Further trials took place in [[Transbaikal]] in 1971.{{sfn|Zaloga|1993|p=1-18}}

===T-72===
Being only a mobilisation model, serial production of Object&nbsp;172 was not possible in peacetime. However, by 1971, even Ustinov was growing tired of problems with the T-64.{{sfn|Zaloga|2015|p=32-33, 38, 40}} In an unclear political process{{sfn|Suvorov|1993|p=6}} decree number 326-113 was issued, which allowed the production of Object 172 in the Soviet Union from 1 January 1972, and freed Uralvagonzavod from the T-64A production.{{sfn|Ustyantsev|Kolmakov|2004|p=58}}

An initial production run began in 1972 at Nizhni Tagil. These were trialed in the Soviet Army. A final trial batch was built as "Object&nbsp;172M" and tested in 1973 and accepted into service as the "T-72" in 1974.{{sfn|Ustyantsev|Kolmakov|2004|p=60}}

Uralvagon KB continued to iterate on the T-72 in a series of block improvements.
Obj. 172M-1 introduced ceramic/steel [[laminate armour|laminate]] turret armour. The [[coincidence rangefinder]] was replaced with a [[laser rangefinder]]. Obj. 172M-1 was designated as the T-72A when it entered production in 1979. Turret armour was greatly improved with Obj. 184. A more powerful V-84 engine was introduced to offset the increased weight. Obj. 184 entered service in 1985 as the T-72B.{{sfn|Zaloga|1993|p=1-18}}

At least some technical documentation on the T-72 is known to have been passed to the [[CIA]] by the Polish Colonel [[Ryszard Kukliński]] between 1971 and 1982.{{Citation needed|date=December 2021}}