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During the height of the Cold War in 1976, the Soviet Union introduced its third-generation of battle tanks into service. Known as the T-80 series, this successor to the T-64 (which had seen use in military operations since the early 1960s) spawned a number of variants.

Also developed alongside the multi-fuel turbine engine-powered T-80 was the T-80UD. Built by the Morozov Bureau in Ukraine, this variant retained the 1,000-horsepower output of its turbine-powered brethren while extending the T-80’s range and overall capability.

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The T-80 series joined the Russian military fleet as the successor to the aging T-64. The third-generation of Russia’s main battle tank was the first MBT to utilize a multi-fuel turbine engine as the main propulsion engine. As a result, the T-80 was one of the most nimble and maneuverable tanks in service when it entered production in 1976. However, the turbine engine proved to be incredibly inefficient, which eventually led to the diesel-powered T-80UD variant. Image: Defence-Blog

More than 5,400 examples of the T-80 would be built over the span of sixteen years. Although production ended back in 1992 for use in the Russian military, the T-80UD and other T-80 variants remain in service around the world in the armed forces of countries like South Korea, China and Pakistan.

In this month’s installment, we’ll take a closer look at the development of the T-80 and the T-80UD variant specifically, and see how the T-80 series’ successor, the T-84, serves as a direct descendent from the diesel-powered iteration of the T-80.

The T-80 Series

As the successor to the T-64, the T-80 shared a similar layout to the machine it would replace – a centrally positioned driver’s compartment at the front the vehicle and a two-man turret directly behind it. Weighing in at roughly 45 tons (depending on how it was equipped), the T-80 utilized a torsion bar-style suspension system rather than the problematic hydro-pneumatic setup used in the T-64. The T-80 also sported longer and wider tracks, which were laid on six forged steel-aluminum, rubber-clad road wheels.

Russian engineer Nikolay Popov served as the chief designer of the T-80 series of tanks. The main gun, a 125-mm smoothbore, was fed by the Korzina automatic loader. It held up to 28 rounds of ammunition in a carousel located under the turret floor. Additional ammunition was stored within the turret itself. The vulnerability of this particular design made the T-80 susceptible to side impacts by RPG fire, which could cause the entire ammunition load to explode. Images: Morozov

However, the real party piece of the early iterations of the T-80 was its 1,000-horsepower gas turbine engine, which gave the tank an impressive power-to-weight ratio of roughly 26 horsepower per ton and a top speed of 43 mph on-road, making it one of the most nimble battle tanks in service at the time.

However, the gas turbine motor had its disadvantages. The T-80’s engine was especially thirsty, which severely limited the tank’s operational range. Morozov Design Bureau, a state-owned company operating in Kharkiv, Ukraine that designed armored vehicles for the Russian military at the time, sought to address the T-80’s range limitations with a diesel-powered variant of the T-80.

Like the T-64 before it, the T-80 series main battle tanks utilized a three-man crew consisting of a driver front and center and two personnel on the turret, with the gunner on the left and the commander on the right. The engine is rear-mounted. Images: Military.co.uk, RussiaDefence

Dubbed the T-80UD, this alternate design would prove to be enough of an improvement over the gas turbine-powered T-80 that the series’ successor, the T-84, would be based on the T-80UD rather than the standard model.

The T-80UD Adds Capability

Though improvements were made to the standard T-80 with the development and production of the T-80U in 1985, its fuel-hungry powerplant and maintenance-heavy configuration remained an ongoing issue.

The solution would come just two years later with the introduction of the T-80UD into the Ukrainian fleet. Powered by a six cylinder 6TD-1 two-stroke turbo-piston diesel engine making 1,000 horsepower, though its on-road top speed was slightly reduced to 37 mph, its 350-mile effective range was a substantial improvement. The diesel powerplant also required significantly less maintenance than the turbine engine used in the T-80U.

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While the SG-1000 gas turbine engine provided impressive performance in the standard T-80, its fuel consumption and maintenance requirements proved problematic. In 1987, the Morozov Bureau in Ukraine sought to address this issue when they introduced the T-80UD. Sporting the improvements first seen in the T-80U two years prior, this new model would ditch the gas turbine engine in favor of a more convention turbodiesel unit. Also making 1000 horsepower, the new motor provided virtually identical performance to its turbine counterpart while simultaneously improving the tank’s range substantially. Image: Morozov

Transitioning to this turbodiesel powerplant also allowed the T-80UD to boast operational fuel temperatures of up to 55 degrees Celsius (131 degrees Fahrenheit) and ford through water up to 1.8 meters in depth. Though the T-80UD shared the majority of the improvements applied to the T-80U, its engine deck, smoke mortar array, and turret stowage boxes differed from its gas turbine-powered counterpart.

The T-84 And T-90 Take Shape

After the fall of the Soviet Union in 1991, the newly-independent Ukrainian government sought to improve upon the T-80 formula. There was a need for a worthy battle tank for both export to other nations, as well as for service in the Ukrainian military.

The T-80’s first and only active combat role came during the December 1994 separatist war in Chechnya, where the T-80’s design flaws were exploited by opposing forces to great effect. Though inadequate training is said to have been a major factor in its overall performance during the conflict, the tank itself was not without issue.

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The T-80 series battle tanks would see just one use in a combat role for the Russian military. In December of 1994, a large number of military personnel and vehicles entered the city of Grozny in Chechnya. However, Chechen rebels were well aware of a fatal flaw in the T-80’s design. Its autoloader propellant was partially vulnerable from the side of the tank, allowing rebels to destroy more than 200 T-80s with RPG fire by causing an internal ammunition explosion. Image: Morozov

Many Chechen rebels knew of the T-80’s weaknesses from Soviet-era military service, and chief among these was a design flaw related to the T-80’s Korzhina autoloader. The propellant for the system was stored in a vertical position, and as such, the tank’s road wheels only partially protected it, leaving the volatile material otherwise exposed to attack.

So, while the tanks were practically impervious to RPG fire from the front, strikes to the side and above the road wheels could, and often did, result in a catastrophic explosion. Thus, over the course of two days of fighting, the most advanced tanks in the Russian fleet were brought to their knees by rebel fighters.

Meanwhile, the Russian government sought to consolidate its fleet – they had three separate tank models in service, each with unique parts requirements, yet all three tanks offered similar capabilities. A Soviet-era project to provide a singular replacement to the T-64, T-72, and T-80 series came to fruition in 1993 when the T-90 came into service in the Russian military, which incorporated a number of features from the T-80 series while providing upgrades to the drivetrain, weaponry, armor, and tactical componentry.

After the fall of the Soviet Union in 1991, the Ukraine became a sovereign state. Russian and Ukrainian efforts to build tanks afterward became wholly independent of one another. Each would build a successor based off the T-80 series of tanks, resulting in Russia's T-90 series (left) and the Ukraine's T-84 (right). Images: Sputnik News, Morozov

Not to be outdone (or overlooked for potential sales to other countries), the Ukrainian government brought the T-84 into the fray in 1994. Based on the T-80UD, the T-84 addressed a number of the weak points found in the T-80 design while also providing a number of improvements its own.

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These included a new all-welded turret, improved reactive armor, and bolstered side skirts. The later provided additional protection against the types of infantry attacks that had proven so effective against the first Chechen conflict.

Although production of the T-80 for the Russian military ended decades ago, variants of the tank continue to be produced to this day at Russia’s Omsktransmash factory in Omsk, Russia for export. For its part, the T-84 has supplanted the T-80 series for use as the main battle tank in the Ukrainian military, and remains in production at the Malyshev Factory in Kharkiv, Ukraine today.