T-55 Medium Tank - Development
With development of the T-54A tank completed in 1951, the Kremlin allowed Aleksandr Morozov to move the main medium tank design bureau back to Kharkov, where it had been based prior to the Great Patriotic War. However, a small design bureau, under Leonid Kartsev, remained in Nizhni Tagil at the "Vagonka" (Uralmashvagon Zavod) plant. Morozov's bureau was assigned to the development of a new generation tank to replace the T-54, while Kartsev's bureau was responsible for the less challenging task of updating the T-54 as necessary.
In 1953, Kartsev was shown the technical-tactical requirements (TTZ) for the new Obiekt 430 being developed by Morozov's bureau. Kartsev was convinced that an upgraded T-54B could satisfy the requirement; so began the competition between the two components of the wartime medium tank design bureau.
The original plan, called Obiekt 140 or T-54M, was a heavily reconfigured design with a new long-barreled D-54 100mm rifled gun. The improved V-54-6 engine was developed at the Barnaul engine plant after Trashutin's main diesel engine design bureau in Chelyabinsk refused to assist Kartsev in this venture. Many other improvements were envisioned for the type, including a new transmission, a modified supension and enhanced night vision equipment. Although a prototype was built in 1954, the changes were too extensive to win government approval. Kartsev turned his attention to less elaborate improvements.
In the 1950s, a state commission for certifying the technical documentation of tanks was held each fall, attended by representatives of GBTU (Main Military Technical Administration), the Mintransmash, the main tank plants and the main subcomponent manufacturers. The meeting was chaired by the production administration of the GBTU Main Armored Directorate. This commission usually approved any plans to upgrade tanks. During the October 1955 commission session, Kartsev proposed a simultaneous set of upgrades for the T-54B tank to the commission head, General Aleksandr M. Sych. Sych approved the proposal, but the plant head, I. V. Okunev, suggested that the upgraded version be designated as a new tank. The project was designated Obiekt 155 and became the T-55 when approved for service use.
One of the most significant improvements in the T-55 were the first stages of a nuclear protective system. With the death of Joseph Stalin in 1953, the Soviet Army began examining the implications of tactical nuclear weapons on the conventional battlefield. By the late 1950s, Soviet tactical doctrine was in a state of flux, the so-called "revolution in military affairs," with growing emphasis being placed on the need to prepare for fighting on the nuclear battlefield.
The Soviets began to study the technical effects of nuclear weapons on tanks from their earliest nuclear bomb trials. On 14 September 1954, they tested a nuclear bomb in the Totskoye region of the Urals during a special wargame to examine the psychological impact on troops of a nearby explosion. Soviet concern over the consequences of nuclear weapons on the battlefield was given greater urgency by the US Army's gradual adoption of tactical nuclear weapons as a counterweight to Soviet numerical superiority in central Europe. By the mid-1950s, Soviet doctrine was beginning to recognize that nuclear weapons would be present on the contemporary battlefield, and that modern weapon systems would have to be able to survive the after-effects of nuclear weapons.
The first manifestation of this doctrinal evolution in tank, design came with the new T-55 tank which was adopted in 1958. A major innovation in the new design was a PAZ nuclear contamination detection and filtration system and an improved system to seal the tank from contaminated outside air.
The PAZ system was based around an RPZ-1M gamma ray detector system. This system, once trigerred by a nuclear blast or nuclear contamination, turned off the engine to alert the crew, and turned on an overpressure system to keep out airborne radioactive contaminants. The mild overpressure of 0.0015 kilobar per centimeter cubed obviated the need for complicated sealing equipment. The PAZ system became a standard feature on all subsequent Soviet tanks, though the later systems were often more elaborate. The T-62A PAZ system included an explosive squib system to automatically close louvres and vent covers. Later PAZ systems also incorporated chemical protection features.
The T-55 closely resembled the T-54B externally. The most noticeable external changes were the deletion of the large vent dome cover in front of the loader's hatch on the turret, and the new, flush loader's hatch. The uprated V-55 engine had been impoved by Trashutin's diesel engine design bureau in Chelyabinsk, and the engine deck was modified. The fuel tanks were reconfigured so that ammunition could be stored in cavities in the forward tank; this saved internal volume and permitted more ammunition to be carried. The practice of fitting BDSh smoke canisters externally on the rear of the hull was omitted in favor of a TDA smoke system which created smoke by injecting fuel into the engine manifold. This freed up space on the rear plate to permit mounting of 55 gallon external fuel drums. An automatic fire extinguishing system for the engine compartment (UAPPO) was incorporated for the first time. An AK-150TS air compressor was substituted for compressed air bottles for engine starting. Other changes had been adopted including an improved transmission, a revolving turret floor, improved oil filtration, and a bilge pump to support the OPVT deep wading system.
Three prototypes were built in 1956 and on the successful completion of trials, the new tank was accepted as the T-55 in the middle of 1957 with production scheduled to begin on 1 January 1958.
The T-55 continued to evolve with modest improvements and was produced for many years in parallel to both the T-62 and the T-64. Indeed, the T-55 outlasted the T-62 on the production lines up to 1979 but was produced in diminishing numbers for Soviet export clients. Total Soviet production of the T-55 probably totaled about 27,500 tanks. Czechoslovak and Polish production is believed to have been about 10,000 tanks combined. This brought total T-54 and T-55 production to about 95,000 vehicles, making this series the most widely produced tank type of all times.
Besides the basic tank versions, the T-54 and T-55 formed the basis for air defense gun vehicles like the ZSU-57-2, armored recovery vehicles like the BTS-1, BTS-2, BTS-3 and BTS-4, and assault guns like the SU-122.
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