India's Arjun | Defensionem

Background:

The Arjun is India’s first attempt to create a main battle tank. First conceived back in the early 1970’s by the Indian Defense Research and Development Organization, on behalf of the Indian Army, it was expected to be ready for production within a decade. It was intended to encompass lethality, survivability and mobility that would enhance the Indian Armored Corps for operations against likely future threats, post the conclusion of the 1971 war. The Indian Army soon after the initial design and development, identified two significant shortfalls in the defense industrial base; the lack to produce a reliable engine and main gun tube. This led to the initial importing of the two critical components. This and other issues, led to several delays to the program, with the end result being the first tanks rolled off the production floor, in 2004, nearly twenty years after the expected initial date thought. Over the last 16 years, the Arjun has continued to receive updates and modernization in its design. The latest version underdevelopment is known as the Arjun Mk 2.

Program Vision and Overview

The Arjun will serve the Indian Army’s in a complementary role, tasked to maneuver through the enemy’s main defense zone as part of an Integrated Battle Group for the purpose of fulfilling the Indian Army’s Cold Start Doctrine (CSD) and deliver decisive lethal effects during the planned armored thrusts envisioned for the CSD. The Arjun complements and enhances the capabilities of the Indian Army by having a secondary production line that mitigates any disruption to their primary tank, their T-90s. The Arjun affords the Indian Army additional growth to take advantage of future technologies, as seen with the Mk 2 program. The Arjun will also serve as a baseline for future tank designs starting next decade and service as a quasi-test bed for the Indian defense industry, where valuable lessons learned will be applied to follow on designs, such as with the Arjun Mk 2 . This factor alone deserves credit as developing from scratch an indigenous tank manufacturing capability was achieved through the Arjun program and has directly aided in India’s national security, a feat that should not be ignored.

Decisive Design

The Arjun is designed to be deployed and transportable by air, rail, sea, waterway and road modes of transportation. It is designed to be survivable against current and emerging threats that the Indian Army is expected to face. The Arjun , will serve in a niche role, focused on specific sectors and areas of operation. This is a result of the design having significant attention paid to its survivability against lethal enemy direct fire, as well as the design intentions of combining the three biggest factors in tank design; mobility, lethality and survivability . The Arjun is able to fire accurately and while on the move through its fully integrated fire control system, which was achieved through collaboration between Indian firms BEL and IRDE, as well as with Israeli assistance with the program. Lastly, the Arjun’s ability to conduct DRI functions, illustrate the capabilities of the Arjun FCS system and the French designed thermal viewer that is used.

Indian Arjun Mk 1-A on display.

Lethal formations

The vehicle possess the necessary automotive functions to help prepare crews by conducting collective training, mission preparation and mission execution to facilitate tactical employment. The Arjun possesses adequate situational awareness, target acquisition data and critical information to orient on threats but lacks advanced thermal imagery and has restricted long range identification capabilities, which is rated at 2 km . The Arjun series will able to receive and pass information horizontally and vertically, within an integrated battlefield network, which is designed with Israeli collaboration and is estimated to be within scope and similarity to baseline FBCB2 like systems. Defensionem anticipates that the Arjun will provide lethal direct fires against expected armored threats and future threats. The Arjun is assessed as being able to achieve parity with other regional ground forces that employ DU sabot rounds, notably due to regional threats employing either the same material solution capability or copied variants, as with the case of China and their DTW-125mm DU round. The Indian 120mm cannon will likely employ an enhanced DU penetrator modeled after the IMI 120mm round sometime within the next decade and will likely have similar ballistic penetration capabilities. This munition will give the Arjun the ability to engage expected threats out to ranges of 2,000 meters. A lethality shortcoming identified is the lack of a tube launched anti-tank guided missile. The Israeli Lahat , the initial contender was discarded as an option over its inability to engage at ranges under 1,200m. India is currently working to rectify this requirement with an indigenous designed missile. There is little to no information as to why the requirement of a tube launched missile needed to be employed at short ranges, considering the kinetic advantages afforded by APFSDS at close ranges. Therefore, Defensionem assesses that Indian DU APFSDS rounds are inferior to chemical energy rounds in terms of penetration at close ranges. Accordingly, it is factored that the Israeli Lahat missile, offered in excess of 700mm RHA penetration at any distance and exceeded the KE performance of Indian DU rounds at ranges at or around 1,200m.

Cut away view of the Arjun Mk 1. Notice the CL V storage along side the drivers compartment and the lack of blow out panels associated with it.

Vehicle Vulnerability Analysis

Defensionem assess via use of a fault tree analysis that cover the main subsystems that, if damaged or destroyed, would cause a communication, mobility, lethality, or catastrophic kill. These types of kills are defined below.

Communications Kill

The vehicle experiences a communications-kill if it is damaged to the extent that it cannot transmit or receive information by its electronic communication equipment, and the damage is not repairable by the crew on the battlefield within 10 minutes. Due to the Arjun employing an integrated communication system that is traditionally mounted, under ballistic protection, the probability of this occurring is low to moderate. Standard vulnerability to radio antennas prevail, as with all designs, but by large and by far, the internal mounting of the majority of the communication systems are dependent upon shock hardening factors, found within the turret layout. Defensionem assess that this layout is traditional to most modern designs and require little augmentation other than cable and or mounting repairs.

Mobility Kill

The vehicle experiences a mobility-kill if the damage causes the vehicle to be incapable of performing any of the mobility requirements of its assigned mission, and the damage is not repairable by the crew on the battlefield within 20 minutes. The Arjun is designed to be able to accommodate an active APS system, from Rafael systems. Considering the limitation of the Arjun of being close to but not yet fielded, the APS system would likely facilitate favorable mobility protection. Further, the Arjun has the ability to mount ERA blocks along the axis of its hull and frontal skirts, especially over its #1 and #2 skirts. This ability mitigates the probability of a mobility kill occurring. It is rated as moderate to low as a result of potential APS employment and ERA blocks along the chassis.

Lethality Kill

The vehicle experiences a lethality-kill if the damage causes the vehicle to be incapable of performing any of the lethality requirements of its assigned mission, and the damage is not repairable by the crew on the battlefield within 10 minutes. The Arjun will employ an indigenously developed 120mm cannon. Whether or not, it uses a rifled 120mm cannon or the Mk 2 version uses a 120mm smooth bore cannon based on Israeli design, the cannon, in whatever version, will afford adequate maintenance and repairs. Probability of a lethality kill for main armament systems occurring is deemed as low. Additional concerns are reduced due to the form of turret power it receives. While a lethality kill will occur if the tank batteries are damaged, the use of hydraulic operation ensures that mechanical functions can still occur even with battle damage, as does the ability to conduct silent watch functions without the vehicle running, thus this feature would allow for continued employment without a fully functional vehicle, albeit however long. The location of the RWS increases the chances of accidental damage from fragments or small arms fire, but the RWS itself has a ballistic mounting. Additionally, the RWS is mounted in front of the loader, affording the crew the protection of repairing and or reloading the machine gun from under partial cover. The probability of the secondary weapons being damaged is deemed low.

All Arjun series retain this shortcoming from incorporating GPS sights internally into a turret as opposed to externally on top of the turret. Further series also add sensors to the right of this, increasing the area on the frontal aspect of the turret that has less armor protection.

Catastrophic Kill (K-kill)

The vehicle suffers a catastrophic-kill if the damage is so extensive that the vehicle is not economically repairable. Items carried on-board the vehicles whose detonation or ignition could result in catastrophic damage would be items such as ammunition, fuel, oil, fluids, etc. Defensionem estimates the Arjun, depending on model, will likely have between 480 to 500mm of RHA armor over the frontal* aspects of the turret, more so if ERA is applied. The Arjun uses a layered approach for ballistic protection, consisting of active defense systems, ERA blocks and Kanchan armor, which is a composite armor package. Kanchan , is a mixed soft material mesh, hexagonal in design and is encapsulated in steel plates, which is based upon 2 st generation composite armor, notably Chobham, foundon Challenger 1 and M1 andsome M1A1 seriestanks. This design is intended to increase battlefield survivability and addresses future enemy lethality efforts post 2020. Visual analysis allows for concern that the Arjun Mk1-A employs spaced and composite armor, in an arrow head design that mimics the T-90 in principle. Critically, the Mk 1-A turret exposes significant turret area in comparison to the Mk 1 model. As noted in above picture, the exposed area surface between the base of the turret and the wedged like armor at the top of the turret, is deemed as a design flaw that could be exploited in engagement scenarios at or around 2,000m. This assessment is based off of probable engagement ranges found west of India’s borders against a prepared and dug in enemy, expecting a CSD attack. Additionally, the question of armor protection on the front right side of the turret, near the gunner’s dog house doors, cause concern, as the cut away of the sights indicate, there is a vacuum and space associated at that location. Simply put, there is less armor there, as it houses the gunner’s primary sights and right of that are additional sensors housed that are not armored. Currently, there are no hull blow out panels, thus reducing the survivability rate of the Arjun in the event of penetration. Probability of catastrophic kills occurring is rated as moderate to low against Pakistani forces and moderate to high against Chinese forces.

Arjun tank with engineering plow attached.

India’s Arjun

Mel Daniels

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