Heavier, more lethal Arjun tank poised for trials

The modified Arjun on which many proposed modifications are already done. Other improvements feature on another test tank. The graphic shows the proposed changes.

by Ajai Shukla

Avadi, Chennai

Business Standard carried a shorter version of this article on , 24th Nov 11

A heavier, more protected Arjun tank, called the Arjun Mark II, is poised for army trials. Scheduled for January and June 2012, successful trials would be the green signal for building 124 Arjun Mark IIs at the Heavy Vehicles Factory in Avadi, outside Chennai. These will supplement the 124 Arjuns Mark I already in frontline service.

Preparing the new Arjun for trials is the Combat Vehicles R&D Establishment (CVRDE), Avadi, which steered the Arjun through a difficult and delayed development process; to its emergence as India’s premier main battle tank (MBT). In March 2010, after the Arjun outperformed the vaunted Russian T-90S in performance trials in Rajasthan, an impressed Indian Army accepted 124 Arjuns into service. But the army has made a follow-on order conditional upon 93 improvements to the Arjun, including 19 major modifications. The CVRDE is finalising these modifications.

Business Standard visited Avadi for a detailed briefing on the Arjun Mark II, the first time the media has actually inspected the tank. This reporter was given unhindered access, including the opportunity to speak to the engineers working on the tank and the army crewmembers that drive and fire it.

The Arjun Mark II’s most remarkable feature is its extra weight, 3-4 tonnes more than the earlier 62-tonne Arjun. For years the army criticised the Arjun as too heavy for India’s road and rail infrastructure; now it wants modifications that will make the Arjun heavier. Fitting Explosive Reactive Armour (ERA) plates on the tank has boosted crew protection, but also increases the weight by one and a half tonnes. An equivalent increase comes from added mine ploughs, which churn up the ground ahead of the tank, uprooting explosive mines that would otherwise blow up the tank.

The Arjun Project leaders, V Balamurugan and GK Kumaravel, are unfazed by the weight gain. During gruelling trials this summer, the Arjun has demonstrated a crucial modification in the transmission system that makes the 65-66 tonne Arjun Mark II more agile than the lighter, 62-tonne Arjun Mark I.

“We ran the modified Arjun for 1,300 kilometres, gradually loading dead weight until it was 65.5 tonnes. We demonstrated that its performance, acceleration, torque, working temperature and fuel consumption were better than the Arjun Mark I,” claimed Balamurugan.

Also modified is the tank's hydro-pneumatic suspension which is now capable of handling a 70-tonne load. This also incorporates some newly-developed technologies to overcome occasional problems that the Arjun Mark I has grappled with during its development period: grease leakage and track shedding.

The trade-off, though, is in maximum speed. The Arjun Mark II does just 60 kmph, compared with the 70 kmph top speed of the Arjun Mark I. But the army has accepted this trade-off. “Tanks need agility and acceleration in battle, not sustained high speed. And the advantages of ERA and a mine plough are enormous,” says a tank officer.

CVRDE chief, Dr P Sivakumar, an award-winning transmission specialist, is jubilant. “Earlier the army was criticising my Arjun [for weighing too much]. But, after seeing its cross-country performance, even compared with a lighter 40-tonne tank like the T-90, they realise that the Arjun moves like a Ferrari. Even at 65-66 tonnes, it will beat any MBT in the desert,” he promises.

Sivakumar backs that with the endorsement of a team from Israel Military Industries (IMI), designers of the renowned Merkava tank. Talking to Indian Army generals after a “third-party evaluation” of the Arjun, Israeli experts declared that the Arjun, especially ruggedised for Indian conditions, would outrun any competition.

Another crucial improvement in the Mark II is the tank commander’s thermal imaging (TI) night sight, which replaces the day-only sight of the earlier Arjun. Now the Arjun can operate at night in “hunter-killer” mode --- the commander as hunter; and the gunner as killer. The commander scans the battlefield through his new TI sight; targets that he spots are electronically allocated to the gunner to destroy, while he returns to hunting for more targets.

The Mark II also equips the driver with a new night vision device based on “un-cooled thermal imaging”, allowing him to clearly see 300-500 metres, even on a pitch-dark night. The “image intensifier” device in the Mark I required some ambient light. A DRDO laboratory, Instrument R&D Establishment (IRDE), Dehradun, has built the new driver’s sight.

“We also now have an ammunition containerisation system. If the tank is hit, and the on-board ammunition explodes, it will blow outwards, saving the crew. A metallic box with ‘blow-off panels’ directs the explosion outwards,” explains Kumaravel.

The man who oversees the Arjun project, DRDO’s Chief Controller for Armament and Combat Engineering (CC-ACE), S Sundaresh, says: “Four major modifications --- the mobility performance at 65.5 tonnes; the commander’s night sight; the driver’s night vision device, and ammunition containerisation --- were validated this summer.”

Coming up for trials in January is an important new capability: missile firing through the Arjun Mark II’s main gun. Israeli LAHAT missiles were proof-fired from the Arjun in 2004, but the sighting and control systems are now being integrated into the gunner’s sight by its vendors, OIP Sensor Systems (Belgium) and SAGEM (France).

The army will evaluate these new capabilities during make-or-break trials next summer. Just one crucial system will come later, perhaps next October: a “laser warning counter measure system.” This senses the laser beam that incoming missiles ride, giving just 10-15 seconds of reaction time. Within milliseconds, the system automatically launches smoke grenades, creating a smokescreen around one’s own tank that leaves the missile operator without a target to aim at.

While the army keenly anticipates the Arjun Mark II’s capabilities, HVF and CVRDE are grappling with a related conundrum: the high cost of the tank, currently estimated at Rs 37 crore.

(Tomorrow: Part II: Bringing down the cost of the Arjun)