The war in Ukraine reignited debates about the role Armoured Fighting Vehicles (AFVs) have today and tomorrow.
The advantages and vulnerabilities of armoured vehicles were demonstrated in this conflict, and armies are expected to embrace the lessons learned from the conflict and implement Technologies, Techniques, and Procedures (TTP) demonstrated as superior. The Eurosatory and AUSA exhibitions of 2022 offered combat vehicle designers an opportunity to showcase trends for the future. Among the elements that best demonstrate these new trends are the turrets featured in this article.
Why Turrets?
The first tanks introduced during World War I employed a tracked system to traverse heavy weapons across the rough terrain, crossing the no man’s land that separated the combatting armies. Like naval gunships or moving fortresses, the first tanks mounted several machine guns and one or two guns pointing forward or sideways covering the vehicle’s surroundings. They were served by a large crew of 8-17 men cramped inside the armoured box to operate those weapons.
For almost two years, these steel beasts evolved into more effective combat vehicles that made their mark on the war. After the war, as tanks evolved into more practical and efficient machines, the gun was elevated from either the hull or sponsons on the sides, to a turret above the hull roof. This position gave the crew better vision through periscopes which provided situational awareness for the crew under the armour protection. The turret’s mantlet protected the gun mount, elevation, and traverse mechanisms, enabling the crew to engage targets through 360°. To serve the weapon, turrets were typically designed to accommodate at least three people, a commander, a gunner, and a loader. The driver and a fifth crew member were seated in the hull.
As combat vehicles evolved through the two world wars and countless conflicts fought over the 20th century, the design of tanks did not change much. Modern tanks carry larger weapons, some use modern composite armour using ceramics or other materials to provide greater protection than rolled homogeneous armour (RHA) steel. Still, the principles are broadly the same – a moving tracked armoured box powered by an internal combustion engine, mounting a large gun in a turret.
Over the past century, combat vehicles balanced mobility, protection, and firepower, considered the classic armour ‘triangle.’ Each design strikes a different balance of the three – a vehicle with superior mobility will often be lightweight and, thus, less protected. A highly protected platform will be very heavy and degrade mobility in cross country, over bridges, or airlift. A big gun that maximizes firepower would require a heavy and less manoeuvrable platform. Therefore, each design seeks a balance that best meets the user’s requirements. Modern designs have added new attributes such as ‘connectivity,’ ‘autonomy,’ or ‘supportability,’ transforming the legacy triangle into a pentagon or hexagon.
Modern turrets are driving this transformation by introducing sensor-based situational awareness and automation of fire control, paving the way for full autonomy with optionally manned and unmanned combat vehicles.
Manned or Unmanned?
Tank turrets reflect army traditions. The turret of main battle tanks (MBTs) always mounts a heavy gun. This manned enclosure requires a high level of protection and a separate ammunition compartment to ensure safety for the crew. An unmanned turret could employ a lower level of protection but requires a complex and heavy automatic loading mechanism for the ammunition. They sometimes also lack the redundancy mechanisms present in manned designs, which enable the vehicle to keep operating in in the event of some component failures. However, the debate on manned or automatic loading appears to have been settled, as the ammunition used with the big guns of tomorrow will be too heavy for manual operation and require an automated loading system in both configurations.
Some designers are already shifting towards unmanned turrets even with existing 120 mm/125 mm guns. The Russian T-14 Armata and General Dynamics Land Systems (GDLS’) AbramsX technology demonstrator are examples of this trend. By contrast, the Franco-German Enhanced Main Battle Tank (EMBT) developed by KNDS and Rheinmetall’s KF51 Panther MBT follow a more traditional layout, having two crew members in the turret plus two in the hull.
A vital capability enabled by the modern turret is the Hunter-Killer functionality, achieved by connecting the gunner sights to a separate, panoramic sight operated by the commander. This configuration enables the commander to search for targets and cue targets for the gunner to engage. When several weapon systems are mounted on board, the crew can opt to employ Killer-Killer procedures, theoretically enabling any crew member to operate a remotely controlled weapon station or missile system using their workstation. This capability is enabled using the ‘glass cockpit’ design. Having several displays stacked on each workstation may pose difficulties for integration in existing vehicles. However, it is being used in newer vehicle designs, such as the Optionally Manned Fighting Vehicle (OMFV), KF51, T-14 Armata, AbramsX, and the latest versions of Israel’s Merkava that embrace some of the technologies developed during the Carmel technology demonstration program.
The concepts demonstrated through the Carmel programme have shown how automation can take over or ‘virtualise’ many tasks required of the crew members. The concept could employ a ‘virtual driver’ that follows the commander’s orders by automatically driving the vehicle by regular voice commands. A virtual system operator can handle drones, and a virtual gunner could aim the gun for firing upon the commander’s order. A virtual commander can supervise all autonomous operations, advising the local or remote crew and following their directions, thus enabling a two-man crew to perform as four. These virtual entities enable a small crew to perform multiple complex tasks with efficiently, on either manned platforms or remotely controlled unmanned ground vehicles (UGVs).
Many armies still follow the manned turret design in their latest combat vehicles. These include the UK with the Ajax and the France Army with the T40 on Jaguar, Australia opted for manned turrets on their Boxer reconnaissance vehicle, and their new Land 400-Phase 3 tracked Infantry Fighting Vehicles (IFV) programme. Italy uses manned turrets on its newest VBM Freccia IFVs, and the Dutch are modernizing their CV9030NL with a more advanced manned turret. These manned configurations balance the past, present, and future. The crew is seated in a position providing maximum visibility and control of their surroundings. At the same time, turret automation enables more display space, enabling the crew members to perform their tasks by interacting with sensors, battle management systems (BMSs), and weapons over large, interactive digital displays. They may also opt to use more immersive displays, such as Elbit Systems’ ‘IronVision’ or Rheinmetall’s Situational Awareness System (SAS), providing the crew the ability to ‘see through armour’ without the need to open the hatches. Such immersive systems are suited for crewmembers seated in turrets, as they often require more intuitive sensing to ‘feel’ a remotely operated weapon’s line of sight.
Unmanned turrets employ automation to separate the person from the weapons. It uses a turret which can often be mounted on top of the hull without requiring hull-penetration, negating the need for a turret ring or a rotating turret basket. For vehicle designers and users, the main benefit of such a configuration is an increase to the available internal volume in the fighting compartment. This can provide benefits such as accommodating a fully-equipped squad inside the vehicle, as well as safer or more comfortable crew seating, improving a force’s capabilities and quality of life.
However, removing the crew members from the turret poses a ‘cultural change’ for armies. Germany and Brazil were among the early adopters of the concept. Germany was among the first to integrate such a highly sophisticated and complex remote turret on the Puma IFV developed by the Projekt System Management GmbH (PSM) consortium of Krauss Maffei Wegman (KMW) and Rheinmetall Land Systems. However, this vehicle has proven problematic and has been suffering teething problems since its introduction in 2018. Brazil opted to install Elbit Systems’ UT30 turret on the IFV configuration of its VBTP-MR Guarani 6×6, an integration which has so far proved to be smooth.
Germany and Brazil were followed by Singapore, Lithuania, Israel, Spain, Poland, Romania, and the US Army, among the armies embracing the changes by introducing new unmanned designs. Singapore was the first to employ Rafael’s Samson turret on the Hunter AFV, and Lithuania also selected a version of this unmanned turret for its Boxer APCs. The Israeli army opted to develop its design for the Namer tracked and Eitan wheeled APCs. Spain also selected the Guardian-30, an unmanned turret developed by the Spanish company Escribano for the IFV configuration of its new VCR Dragón 8×8, while Poland is fielding the ZSSW-30 unmanned turret developed by HSW as a successor to the OTO Melara Hitfist-30P turret currently used on the Rosomak. The ZSSW-30 will also equip the Poland’s new locally-developed Borsuk tracked IFV. The Polish MoD also considers this turret a lower-cost alternative to the manned turret used on the Redback IFV being considered by Australia for the Land 400 phase 3 project.
Turret-Mounted Protection Systems
Passive armour protection represents only one of many layers of the ‘survivability onion’ model of an armoured vehicle. The turret substantially adds to the overall vehicle’s weight. Therefore, removing the crew allows for reducing the turret’s size, which in turn requires less or lighter passive protection, contributing to overall weight reduction. Among the survivability aspects related to the turret are its shape and composition. Using cast armour with additional armour plates welded to the outside or making the entire turret out of steel plates are two different approaches. The welded, trapezoidal shape is typical in modern Western designs, while the rounded cast turret was typical of western designs until the 1970s, and most Soviet T-series tanks until the T-90 and T-14.
While the cast turret is cheaper to produce and results in a lower weight overall, adapting add-on armour to the rounded shape requires complex structural elements of add-on armour that can often leave vulnerable areas around it. The welded turret has a heavier baseline weight, but typically uses hardened steel plates, which add around 10% hardness and offers easier integration of additional passive and reactive protective layers. Introducing active protection systems (APSs) adds significant protection to both types, mainly against shaped charges, thus enabling designers to optimise the passive armour against kinetic threats.
Traditionally, the tank has the heaviest armour up front to protect from threats coming head-on. However, due to the character of modern warfare, tanks have become more likely to be engaged from all directions, including from above or below. Since using heavy armour to protect all directions is not feasible, APSs are increasingly seen as a necessary part of the vehicle’s protection package. These using active effectors to intercept, destroy or divert the threat before impact. Current APSs, such as Rafael Advanced Defense Systems’ Trophy, protects against shaped charge warheads. Elbit Systems’ Iron Fist and Rheinmetall’s Strikeshield also add some protection against kinetic energy (KE) projectiles. However, neither can intercept threats coming from above or below the tank. Recent wars have demonstrated that these are the most vulnerable attack vectors threatening tanks and AFVs.
Presently, protection against top attack remains in the realm of ‘Soft kill’ APSs, which use aerosol or smoke screens to deny the threat’s sensors from acquiring the target, rather than defeating the threat on a direct engagement. Such countermeasures are typically emplaced on the sides or the top of the turret, enabling protection against multiple attacks. Rheinmetall’s Representative top-attack countermeasures are the ROSY obscurant smoke salvos or the Russian 3VD35 aerosol developed by the Central Scientific Research Institute of Precision Engineering (TsNIITochMash) for use by the Russian Armata T-14 MBT and T-15 heavy IFV (HIFV).
The radar and optical sensors used by APSs also play an essential role in establishing situational awareness for the crew and the combat formation. These sensors, constantly staring around the vehicle, searching for threats, offer an unprecedented level of situational awareness that enhance more typical early warning systems on board, such as laser warning receivers (LWRs) and acoustic shot detection systems devices.
The Evolution of Firepower
The tank gun enables armoured formations to engage all types of targets encountered in their direct line of sight – tanks and armoured vehicles, anti-tank guided missile (ATGM) teams, attack helicopters, structures, and fortifications. In the 1960s, the 105 mm rifled gun became the standard gun for Western tanks, but most of these were replaced by the 120 mm smoothbore gun around the end of the last century. This gun provided much higher performance, primarily with kinetic energy (KE) projectiles. Despite this shift, the 105 mm rifled gun is still used and has recently been selected for new production series, including General Dynamics Land Systems’ (GDLS) Griffin II, which was chosen for the US Army’s Mobile Protected Firepower (MPF) and GDLS/Elbit Systems’ ASCOD 2 Sabrah light tanks recently delivered to the Philippines. In both cases the 105 mm rifled gun offers weight saving compared to a larger gun, and adequate firepower for the role.
Towards the new millennium, advancements in electronics, optronics, and automation shaped the modern main battle tank, equipped with high pressure 120/125 mm gun firing KE or high explosive anti-tank (HEAT) rounds that could penetrate almost all types of enemy tank armour. The main difference from earlier generations is the introduction of automatic loading and ammunition handling, enabling the reduction or total elimination of humans from the turret.
Most Western armies use manually-loaded 120 mm guns on their tanks, a notable exception being the CIO Centauro II fire support vehicle used by the Italian Army. The vehicle is armed with the 120/45 gun, which is provided with an autoloader installed in the Leonardo Hitfact MkII turret. Today, the Rh120 L55 series represent the West’s premier in-service 120 mm high-pressure guns, which first saw service with Germany’s Leopard 2A6 MBT. The improved L55A1 model has been selected to replace the Challenger 2’s legacy 120 mm rifled gun as part of the Challenger 3 (CR3) upgrade, which is due to start entering service around 2027. Having said this, 120 mm gun development continues, as shown recently with the AbramsX demonstrator armed with the new XM360 gun. This model features a higher impulse and chamber pressure, as well as a shorter recoil stroke, and lower felt recoil thanks the addition of a pepperpot muzzle brake.
By the mid-2020s, larger-calibre guns are due to have matured. They are presently being tested for use with the MBTs of the 2030s, with the 130 mm L52 gun developed by Rheinmetall, the ASCALON 140 mm gun designed in France for the future Franco-German Main Ground Combat System (MGCS), and the 2A83 152 mm gun developed in Russia for Object 195. Although Russia’s 152 mm gun was dropped in favour of the 2A82-1M 125 mm gun on T-14, the larger 2A83 may yet resurface in a future design.
All designs strive to field projectiles that will overmatch the most potent enemy armour from a longer distance. For guns in excess of 120 mm, specialised systems are required to handle the ammunition and load the gun to serve big guns, as the cartridges are too heavy for manual handling. Thus, the position of loader became redundant, thus the fourth crew member can either be eliminated or moved to the hull to operate other mission systems such as drones. Unmanned tank turrets are beginning to appear in MBTs such as the Russian T-14 and American AbramsX, which is still a technology demonstrator. The Franco-German EMBT demonstrator has a two-person turret with two crew in the hull, the fourth of which is the ‘systems operator’. Similarly, three crew members are the default manning requirement for the Rheinmetall’s KF-51, but a fourth can be optionally added in the hull. They are provided with digital displays for operating the weapons and mission systems. The KF51’s turret is equipped with a total of 20 ready rounds in two magazines, with fully automatic loading and unloading of ammunition. The system can operate in various degraded modes and use manual override in an emergency.
Electrical drives have long replaced hydraulically-actuated turret traverse and gun-laying systems in MBTs, and advancements in electric propulsion and power generation on board further increase such systems’ performance, speed, and response time. Nevertheless, self-propelled artillery systems considered less vulnerable to enemy fire still employ these hydraulic systems.
For the big guns, designers want to place the gun as low as possible, both to more easily enable the tank crew to employ hull-down firing positions in defilade, but also seek to reduce the overall vehicle silhouette, to minimise exposure in the firing position. Modern Western tank turrets tend to use external ammunition stowage placed in the bustle (the back of the turret). This is connected to the turret by a blast door and has blow-out panels designed to vent an explosion to the outside in case the ammunition stowage is compromised. Without this separation of ammunition from the crew compartment, penetration leading to ammunition cookoff can cause the explosion to vent into the fighting compartment, causing a catastrophic kill. This was relatively common problem with Russian tank designs until the introduction of T-14 Armata, which fully isolated the crew from the ammunition.
Smaller turrets with autocannons are more versatile in design. Lighter vehicles are typically equipped with 30 mm automatic cannons, and for many this was an upgrade from the 20 mm and 25 mm cannons fielded with the IFVs of the 1980s. Such automatic cannons include the Rheinmetall Mauser MK 30-2 and Northrop Grumman with the MK44 Chain gun and its XM813 derivative. The MK-30-2/ABM has been used as the main armament of the new German Puma IFV and the Australian Boxer Combat Reconnaissance Vehicle (CRV).
With its distinctive muzzle-mounted ammunition programmer, the weapon is capable of using air-burst munitions, maximising lethality against soft targets such as infantry and drones. Rheinmetall also offers the Skyranger 30 turret, which supports very high elevation (85°) and a rapid traverse rate, intended for the mobile very short range air defence (VSHORAD) role.
The dual-feed XM813 automatic cannon uses the same ammunition as the MK-30-2 but also uses a different explosive airburst munition developed by Northrop Grumman. This munition uses a time-based fuse, which is programmed during firing to trigger the explosive fragmenting charge at a preset time that corresponds with the target range and the travel time of the round. These munitions are particularly effective against drones and personnel in the open.
From its inception, this weapon was offered with ‘up gunning’ option, enabling turrets to up gun the main armament from 30 mm to 40 mm ‘Super Forty’ or to 50 mm ‘Supershot’ with relatively minor changes. While the 40 mm ‘Super Forty’ offer was not a big success, the XM913 cannon, chambered for 50 mm ‘Supershot’ ammunition has been selected as the future IFV weapon for the US Army due to its high lethality and extended range. A turret incorporating this weapon was recently developed by Elbit Systems, demonstrating the integration of the XM913 and many of the company’s systems. Elbit Systems has teamed with BAE Systems to compete in the US Army’s OMFV program. The two companies have successfully cooperated in integrating the Iron Fist APS for the new generation turrets produced for the Dutch CV9035NLs and Czech CV90 MkIVs. This turret will soon begin firing trials and is proposed by one of the teams competing for the future OMFV. Another team, including Rheinmetall America, Raytheon Technologies, Textron Systems, and Allison Transmission, is proposing a derivative of the German KF41 Lynx with a turret mounting the same XM913.
Beyond their primary armament, most turrets will typically employ several additional weapons. These include remotely operated weapon stations mounting 5.56 mm, 7.62 mm, 12.7 mm, up to 30 mm or 40 mm weapons. Such weapon stations are being used on manned and unmanned turrets alike. The smaller calibre weapons are used primarily for closer ranges while the 30 mm using airburst munitions is considered a near-term solution against drones.
Another new capability associated with modern turrets is an added weapon compartment used for housing launchers for guided missiles and loitering munitions. Most of the new turrets use a retractable ‘pop-up’ container protected under armour until it is erected just before firing. Today, these containers are designed to accommodate a specific type of missiles, like Rafael’s Spike LR or MBDA’s Akeron-MP, or the Uvision Hero-120 loitering munition. Rheinmetall is also considering a solution which fits nine miniature drones, acting as a swarm of loitering munitions deployed from such a compartment.
Human-Machine Integration
A fully equipped unmanned turret provides AFV designers with an excellent opportunity to introduce new capabilities with minimal changes to the platform. Since most sensors and weapons are mounted outside on the turret and remotely controlled from workstations inside the hull, most integration work focuses on the turret. That’s why designers employ open systems standards, such as NGVA or MOSA, enabling systems to interface with the same data formats, making integration and upgrades more efficient with less developmental risk.
Integrating all those systems with the crew is not easy either, since new capabilities should also not increase the workload on the crew or impede their function. Situational awareness is a good example of this challenge – an unmanned turret requires providing the vehicle with a greater level of situational awareness, since the commander cannot look out of the turret to get a first-hand understanding of their surroundings.
Different sensors operating in other modes are essential to monitoring the battlespace around the combat vehicle. Using a combination of standardised operating consoles, digital displays, and wearable immersive augmented reality (AR) vision systems can provide a more intuitive and realistic operating environment that young soldiers have already developed in gaming and implemented in real life.
Tamir Eshel