Mittwoch, 19. April 2017

US armor modernization plans

The armed forces of the United States of America are running a number of projects to modernize the land vehicle and amphibious vehicles during the next few years. The Armored Multi-Purpose Vehicle (AMPV), based on a modified Bradley chassis, will replace the obsolete M113 (not called Gavin) in the Army's inventory. The AMPV features enhanced protection against mines and improvised explosive devices (IEDs), a total of 2,907 AMPVs will replace the M113-based vehicles as general-purpose vehicles, mission command vehicles, mortar carriers, medical evacuation and medical treatment vehicles in the US Army's Armored Brigade Combat Teams (ABCTs). On the long run a further 1,922 AMPVs might be procured, if the M113 should be replaced at brigade level (and lower) on a one-to-one basis by the AMPV.

AMPV in the medical evacuation variant
In general both Army and USMC are interested in upgrading or replacing the existing medium weight personnel carriers (both APCs and IFVs) in the near future. The Army is working on improving the  M2 Bradley and the Stryker, developing ECPs (engineering change proposals) and prototypes for future enhancements. The Marines meanwhile are working on a survivability upgrade of the tracked Amphibious Assault Vehicle (AAV), which is being developed by SAIC. It includes a new ceramic armor package (which supposedly offers the same protection level as the currently used Israeli-developed spaced applique armor, but improved buoyancy), an underbelly plate against mines, blast-absorbing seats for the passengers and crew aswell as improved mobility thanks to a new transmission and upgrades to the engine. The other big ground forces project of the USMC is the Amphibious Combat Vehicle (ACV), a 8x8 wheeled vehicle with amphibious capabilities. Two contenders have been shortlisted, one of them being a proposal from SAIC and ST Kinetics, while the other offer is a version of Iveco's proven SuperAV incorporating technology from BAE Systems. However the US Government Accountability Office (GAO) has proposed to move the decision on the ACV into the fiscal year 2019.

Stryker Dragoon design overview
The US Army has recently accepted a prototype version of the Stryker 8x8 wheeled vehicle fitted with a Kongsberg Protector MCT-30 turret, which is armed with a fully stabilized 30 mm XM 813 chain gun, based on the Mk 44 Bushmaster II from Aliant Techsystems (ATK), as urgent operational requirement for the Germany-based 2nd Cavalry Regiment (aka the 2nd Dragoons). This variant of the Stryker is known as the Stryker ICV Dragoon or simply Dragoon, the official designation is XM1296. The vehicle is expected to enter actual troop service in May 2018.

The Stryker Dragoon is fitted with an unmanned MCT-30 turret from Kongsberg
Aside of the 30 mm cannon, the unmanned MCT-30 turret can be fitted with an optional coaxial machine gun, that is externally mounted above the gun shield, but apparently the US Army hasn't opted for it. Another option not taken on the Dragoon is the inclusion of a separate sight for the commander, which would have enabled the vehicle to be used in hunter-killer operations. The gunner is provided with an optronic unit including a thermal imager, a daysight camera and a laser-rangefinder.
The MCT-30 turret stores only 150 rounds of 30 x 173 mm ammunition (two types, of each 75 rounds), however unlike other unmanned turrets it can be reloaded from the interior, if the space below the resupply hatch is not occupied. It offers only limited ballistic protection, reaching only STANAG 4569 level 1 in the base configuration. With applique armor the protection can be boosted up to level 4 (resisting 14.5 mm AP ammunition fired from 200 metres distance); the Dragoon's turret is fitted with bolt-on armor, however the exact protection level has yet to be revealed. 

The new Stryker variant is not without it's issues. With only 81 old Stryker ICVs being converted to the Dragoon variant, is it a rather rare and hence will be relatively expensive. Spare parts might be limited and only be supplied to the repair depot(s) in Germany, making operations outside of Europe rather unlikely. The 30 x 173 mm calibre is also not very common in the Army, but used by the Airforce and Navy (with ammunition types not necessarily suited for the Dragoon). 
It is also limited in capabilities due to the fact that the Dragoon is based on rebuild Stryker with flat-bottomed hull - not on the improved vehicle with double-v hull, that was adopted after the Stryker's vulnerability to mines and IEDs became apparent. This means the vehicle is not suited for assymetrical and hybrid warfare, but also suffers from being non-optimal in conventional warfare (seeing how Soviet/Yugoslavian anti-tank and anti-infantry mines lead to the adoption of many mine protection kits during KFOR and how popular mines have become in Ukraine).
The Stryker Dragoon should be considered an interim solution, designed following an urgent operational requirement. If the Army decided to increase the amount of Dragoons, it should take a number of steps to enhance the basic design. Lithuania for example has ordered 88 Vilkas infantry fighting vehicles (IFVs), which are Dutch-German Boxer wheeled 8x8 vehicles fitted with the Israeli-made Samson Mk II remote weapon station (RWS). This offers the same level of protection as the Kongsberg Protector MCT-30, is however including a dual-launcher for Spike-LR ATGMs and an independent optic for the commander. Furthermore the Boxer includes a multi-layered composite floor to protect against large anti-vehicle mines, while the frontal area of the hull is resistant to the Soviet-made 30 mm APDS ammunition at combat ranges. Such ammo is currently still used by the Russian Army.

The M551 Sheridan was the last light tank operated by the US military
A key project for the US Army is to adopt a Mobile Protected Firepower (MPF) vehicle to provide infantry units with enhanced firepower against opposing infantry, fortifications and lightly armored vehicles. According to the Army's requirements, the main gun has to be stabilized for on-the-move firing, while the optics and fire control system should support operations at all weather conditions including night operations. The new vehicle is required to be air-transportable via a C-17, although transportability with a C-130 is desired. The MPF vehicle should be capable of being low-velocity air-dropped from said aircrafts with initial combat capability (main gun and coaxial armament ready without any need for the installation or adaption of the equipment). The MPF vehicle has to be able to operate 24 hours in IBCTs (infantry brigade combat teams) without refueling. Protection has to be provided against small arms fire and artillery fragments with the option to install additional armor kits, including an underbelly plate against mines and IEDs.

The LAV-25A2 features add-on armor and a two-men tuurret fitted with a 25 mm Bushmaster chain gun
The US Army is currently experimenting with the USMC's LAV-25A2, an 8x8 vehicle based on the Swiss Piranha-design, in order to figure out the role of the future MPF vehicle, aswell as to develop tactics, techniques and procedures for the new vehicle. Soliders of the 82nd Airborne Division (at least some of the men belonging to the 73rd Cavalry Regiment) were trained on the LAV-25 in the past months before putting the new learned knowledge into use during training and excerises. Based on how well the LAV performs, the Army will create a number of new tactics and probably also a few more specific requirements. The LAV-25 itself is obviously not well suited for the current Mobile Protected Firepower requirements; it is being unnecessarily bulky and is using outdated armament, so it most likely won't even be considered by the US Army.
Despite some members of the US Army wishing for a lightweight MPF vehicle, which could be air-dropped and would be armed with a 50 mm autocannon, the Army has apparently decided to focus on a larger concept armed with either a 105 or 120 mm gun - that's at least what the industry has been proposing to the Army, following first talks between industry representatives and Army officials. The US Army hopes to field a solution for the MPF by the mid-2020s.

The Griffin technology demonstrator for the MPF program
General Dynamics is offering the Griffin tank, a light/medium weight vehicle testbed based on the proven ASCOD design, to start a conversation with the US Army on the topic of mobile protected firepower. To be more exact, it is said to be a variant of the improved ASCOD 2 design, which is also used for the British Scout-SV vehicles such as the Ajax. The turret of the Griffins is based on the Abrams' turret design, but is made of more weight efficient aluminum and lacks any sort of composite armor. It is fitted with the lightweight 120 mm XM360 gun originally developed for the Future Combat Systems, but can accept other types of 105 mm rifled or 120 mm smoothbore guns aswell. The gunner is provided with an optical daysight and a thermal imager, but there is no independent sight for the commander.
The weight of the vehicle is about 29 metric tons, the protection level has not been mentioned by General Dynamics representatives at AUSA 2016. However based on the lack of applique armor (as used on the Scout-SV Ajax and ASCOD Ulan), it seems unlikely that the vehicle manages to reach all-round protection against 14.5 mm AP ammunition.

M8 Armored Gun System with rubber band tracks
BAE Systems on the other hand is offering an updated version of the M8 Armored Gun System (AGS), the last light tank developed in the United States, but never adopted by the Army. The AGS has the advantage of being the only purpose-built light tank on offer in the Western world, being not based on a unnecessarily large infantry fighting vehicle (IFV) chassis.
There are variants of the M8 AGS fitted with either a rifled 105 mm XM35 gun or a 120  mm smoothbore gun. Up to two machine guns are provided for the crew: a coaxial 7.62 mm MG and a heavy, roof-mounted 12.7 mm M2 Browning machine gun, The vehicle uses a modular armor concept to adapt weight, ranging from approximately 19 to 25 metric tons, and protection level to the available transport methods and the threat scenario. This concept includes composite armor, perforated armor and explosive reactive armor (ERA). In the basic configuration, the vehicle is only protected against small arms and artillery splinters only. Up-armored to the second armor configuration, the vehicle becomes resistant to heavy machine gun (HMG) fire. Fitted with the third and heaviest armor kit, the vehicle becomes frontally resistant to Soviet-made 30 x 165 mm armor piercing (AP/APDS) rounds and light rocket-propelled grenades (RPGs) without tandem charge warheads.

The vehicle is fitted with a modern fire control system including a daysight, a thermal imager and a laser rangefinder for the gunner. The gun is fully stabilized two axis. There is no proper independent commander's optic, thus the AGS lacks hunter/killer-capabilities just like the Griffin. The updated version of the M8 AGS is also fitted with a camera system for enhanced surveillance of the vehicles surroundings and weight-efficient rubber band tracks.

The NGAFV with Cockerill 3105 turret has been offered for the MPF requirement
Not only BAE Systems and General Dynamics are interested in the MPF contract - the Singaporean company ST Kinetics has also shown interest in providing a vehicle for the US Army's MPF requirements. The vehicle offer is based on a new and still unnamed, tracked APC/IFV chassis developed for to replaced the obsolete M113 Ultra APCs in the Singaporean Army. Currently it is being refered to as NGAFV (next gen armored fighting vehicle). The NGAFV is a tracked vehicle, which is fully digitized. It features a camera system for 360° surveillance and drive-by-wire technology. For the Mobile Protected Firepower program, the NGAFV has been fitted with a Cockerill 3105 turret from the Belgian company CMI Defence. This turret is armed with a 105 mm rifled gun with muzzle break, that can also accept ammunition with a higher pressure. It also can be used to fire the Falarick gun-launched ATGM, a co-development of the Belgians with a Ukranian partner. The turret is crewed by only two men, an autoloader in the rear bustle is responsible for taking over the loader's job. The turret features independent optics for gunner and commander, modern thermal imagers for night operations, and a coaxial machine gun.
The protection of the Cockerill 3105 turret can be adjusted from STANAG 4569 level 1 to level 5, depending on the customer's wish. Two banks of four smoke grenade launchers each provide the ability to disguise the vehicle and evade unwanted attention.

The NGAFV in the infantry fighting vehicle configuration
Unfortunately there aren't many details on the NGAFV available. It has a weight of 29 metric tons when fitted with the locally made Adder RWS with 30 mm gun, so the offer for the MPF vehicle is expected to weigh more than 30 metric tons. It is protected by composite armor of unknown origin to reach a currently unknown level of protection, but estimates from the Defence Technology Review magazine put it at STANAG 4569 level 4 ballsitic and level 4a/4b blast protection. Details on the powerpack are also lacking, aside of the vehicle having an engine output of 711 bhp and utilizing ST Kinetic's own HMX3000 fully automatic transmission. According to the Singaporean Ministry of Defnece, the NGAFV was considered to be the most cost-effective option for replacing the M113 Ultra.

The ACV contender based on the Terrex 2 design
The Singaporean company has a history of trying to sell it's products to other countries: The Bionix tracked vehicle was offered to the US Army as alternative to the wheeled 8x8 Stryker. ST Kinetics teamed up with Otokar to pitch a licence production of an improved Terrex 1 (known as Yavuz) to the Turkish Army. The Terrex 3 was used as base for the failed Sentinel II offer for the Australian LAND 400 program, while the Terrex 2 is currently being evaluated by the US Marine Corps as part of the Amphibious Combat Vehicle (ACV) program.
It seems rather unlikely that ST Kinetics' offer for the MPF vehicle will be successful, there is apparently a lack of competitiveness in vehicle performance or a lack of connections to decision-makers as proven by the failed tenders in Australia, Turkey and the United States.

M1A2 SEP v3 main battle tank
Meanwhile the M1 Abrams will be upgraded to the M1A2 Abrams SEP v3 configuration, development and testing of this is currently under way. First contracts for the development were awarded in 2015. In 2016 testing and development was continued, the new M1A2 Abrams variant is expected to become fully operational after the final full-up system-level live fire testing currently scheduled for 2019. The M1A2 SEP v3 features improved electric systems and power generation to deal with the increased power demands on main battle tanks (MBTs) following the integration and adoption of more electronics or other power-consuming components. Improvements to the networked warfare abilities are also an aspect of the new upgrade.

M1A2 SEP v3 with steel simulators to represent weight changes in armor and internal components
A big part of the third iteration of the system enhancement package (SEP) will be focused on improving the tank's survivability. To deal with the increased armor penetration characteristics oof modern ammunition and missiles, the Abrams' armor will be replaced with a newly developed NEA package. NEA stands either for Next Evolutionary Armor or New Evolution Armor, both names have been used in official documents. For the development of the NEA, three Abrams tanks were provided as Government Furnished Material (GFM) to a contractor. The contractor had to remove the old armor package from the tanks, install the NEA package and investigate the impact of the weight increase on mobility.
Furthermore a new underbody anti-IED kit will be installed on the tank. Together with other changes this kit will reduce the vulnerability of the Abrams to mines and improvised explosive devices. One of the measures is redesigning the crew seatings and fitting additional floors stiffeners to the floor structure. The material and dimensions of the structural supports will be altered to better resists large mine blasts. The crew will also be provided with lower limb protection.
The optics of the CROWS-LP are aligned horizontally
The M1A2 SEP v3 features a new digital interface - the so called Ammunition Data Link (ADL) - for the main gun, which will enable the usage of programmable multi-mode 120 mm ammunition. The older CROWS remote weapon station (RWS) is being replaced with the M153A1E1 CROWS-LP (low profile) variant, which doesn't block as much of the field of view and is about ten inches smaller, thanks to the ammo box, the laser rangefinder and the sights being located at the side of the gun rather than below the gun. Third generation thermal imagers have been investigated for installation in the main battle tank, but apparently will not be part of the third SEP variant. The M1A2 SEP v3 also has a more powerful auxiliary power unit (APU), which is located under armor.

The M1A2 Abrams SEP v3 will be followed by a fourth version of the System Enhancement Package, the M1A2 SEP v4, somewhere in the 2020s. Exact details of the M1A2 SEP v4 upgrade are not known (as development details have yet to become public), however the tank is said to then feature improved networking capabilities, next-generation optics - including a new laser rangefinder and color cameras, weather sensors, a laser-warning system and third generation thermal imagers. The internal electronics will be reworked, streamlining the concept and reducing the number of parts. The M1A2 SEP v4 will supposedly utilize the Advanced Multi-Purpose (AMP) round, which utilizes the ADL found on the SEP v3 and v4 versions.
Supposedly the M1A2 Abrams SEP v4 will be lighter despite being better protected. That future Abrams versions would become lighter without sacrificing protection is something that has been proclaimed even before the M1A2 Abrams entered service in the 1990s. While modern armor technology might allow some weight reductions, it's questionable if this would make any difference compared to the state-of-the-art NEA to be integrated in the SEP v3 main battle tanks.

Artist's illustration of an Abrams with Trophy
One project of the US Army and the US Marine Corps that has been mentioned in the past, is the planned adoption of an active protection system (APS). Apparently there is a big misunderstanding in this regard: The military is currently testing the Iron Curtain, Iron Fist and Trophy systems (testing of the Rheinmetall Active Defence System might start once the budget is cleared for purchasing a number of test systems), but merely for the sake of testing and evaluating currently available solutions. Neither the Army nor the USMC have a current intend to purchase an APS in the next years, at least according to budget allocations and the Congressional Research Service (CRS): "Both Army and Marine officials emphasized to CRS that their respective APS efforts are not in any sense either acquisition programs or Programs of Record by DOD definition. Although there is not a Joint Program Office (JPO) for APS, both services are working in concert on their respective APS programs, which they currently characterize as “vehicle capability assessments” and “technology demonstrations,” respectively, as opposed to formal acquisition programs."
A decision wether the US Army will acquire any APS will not happen before FY2018. Meanwhile "[T]he Marines describe their APS efforts as a “technology demonstration” [...]."

The longer gun barrel of the 155 mm ERCA gun
While it is not sure yet if the designation M109A8 will be adopted after the next upgrade, the US military has handed out a request for information (RFI) for the development of a future upgrade of the M109A7 self-propelled gun (SPG). The M109A7 Paladin Integrated Management (PIM) is an evolution of the 1960s M109 SPG, featuring numerous upgrades to drivetrain, powerpack, electronics and gun. Compared to the original vehicle, it includes improved ballistic protection, better electronics, newer sensors, electric drives instead of hydraulic ones, and numerous other changes. The M109A7 uses a new chassis derived from the M2 Bradley infantry fighting vehicle, featuring the same powerpack and tracks for reducing costs and improving logistics.
However it still has a relatively short gun barrel, which results in a shorter range than other current artillery systems. The M109A7 also has a lower rate of fire (ROF) compared to modern self-propelled gun designs such as the K9 Thunder and the Panzerhaubitze 2000. 

In a first step, the contractor answering to the RFI should modify the M109A7 design to integrate the XM907 Extended Range Cannon Artillery (ERCA), the XM208 gun mount and new drive systems into the vehicle. The ERCA was developed by the US military and uses a longer 155 mm L/52 gun barrel, which increases the effective combat range to the same level as other modern artillery systems. In a second step the contractor is required to modify the M109 design in order to fit the government furnished autoloader into the vehicle.
While these changes would enhance the M109A7 dramatically, such a hypothetical upgrade still would leave several aspects of the vehicle to be upgraded. E.g. the US Army demanded a higher level of protection and mobility in past SPG projects such as the XM2001 Crusader and the XM1203 NLOS-C.

BAE proposal for the failed GCV program
According to current plans from the US TARDEC (Tank Automotive Research Development and Engineering Center), a replacement for the the M2 Bradley (and possibly the M1 Abrams) will be developed in form of the Next Generation Combat Vehicle (NGCV). The vehicle is meant to transport a "half squad" of six men and has a crew of two - the latter figure being a reduction in crew members compared to the current Bradley. Because the US Army's doctrine focuses on very large infantry squads, two NGCV IFVs will transport a single infantry squad - this seems to be a lesson learned from the US Army atempt to develop the Ground Combat Vehicle (GCV), which due to carrying a nine men squad ended up being too heavy, too large and too expensive. Subsequently the GCV was canceled.
How exactly the NGCV will look and what it's capabilities will be is yet to be determined. It will replace the Bradley, but it also could turn into a wider program, being used as basis for a number of different variants, just like the T-14/T-15 Armata vehicles or like originally planned for the canceled Future Combat Systems (FCS) program. Then the NGCV could also serve as replacement for the M1 Abrams and possibly for the Stryker and MPF vehicle.
However the US Army doesn't want to repeat the mistakes from the FCS development: Instead of trying to develop a whole family of very advanced vehicles at the same time, the NGCV will be developed in iterative steps using rapid prototyping. This means that after an initial prototype with a certain set of capabilities has been designed, the system will be evaluated and then a more advanced prototype will be built with enhanced capabilities, based on the experiences with the previous version. This also allows to react to changes in the threat scenario and operational experience, something that wasn't possible with the development path chosen for the Future Combat Systems.

The Army hopes to field the NGCV by 2035. The industry has been asked to form development teams that create proposals for the NGCV or technology that should go into the project. The best design will be chosen by TARDEC and it's makers will be awarded a contract - according to current plans by September 2017. TARDEC and the contractor will develop and test a first prototype desgin over the following seven years. At least two IFV variant NGCV prototypes will be made. In the following three to four years, an enhanced second iteration of the NGCV prototype design will be created, potentially followed by even more. The fiscal year 2021 or 2022 will decide what happens with the Next Generation Combat Vehicle program - if funded, the vehicles could be ready by 2035, assuming everything goes according to schedule. Seeing how France and Germany supposedly will finish (or already have finished) the conception phase of the Main Ground Combat System tank project with 130 mm gun, but still expect to field the vehicle only by 2035, the Army's schedule seems to be quite ambitious... maybe a bit too ambitious?

Sonntag, 12. März 2017

Production version of the Karrar MBT unveiled (updated)

The new main battle tank (MBT) of the Iranian armed forces has finally been revealed to the public in March 2017. The original tank revealed as the so-called "Karrar" was an upgraded version of the T-72S Shilden, the last Soviet export version of the T-72 main battle tank. 

T-72 being upgraded to Karrar

The Karrar is inspired by the latest Russian T-90MS tank, an enhanced version of the T-90. Unfortunately finding detailed information in English about Iranian tanks is rather problematic, so that the exact relationship between the T-90MS and the Karrar remains uncertain. According to Iranian news websites, the army tested the T-90S or T-90MS in or before 2015, but penultimately rejected buying the tank in favour for a local alternative. This lead to the development of the Karrar, but it is not entirely clear if it is meant to be a copy of the T-90MS or the similarities between the two tanks are result of the a cooperation with the Russian industry. Both versions have been mentioned in different forums and blogs.

The Karrar features a new welded turret

The Karrar tank is still an upgraded T-72S, but it is fitted with a completely new, welded turret as newly released video footages shows. It is also fitted with digital control panels and a battlefield management system. The base armor package of the Karrar's turret was improved, offering a higher level of protection compared to the older composite armor in the cast T-72S turret.

The Karrar provides digital control panels for the crew

Compared to the T-72S Shilden, the current MBT of the Iranian Army, the Karrar offers improvments to armor protection, firepower and electronics. There is no indication that the engine was altered, so the mobility appears to be equal to that of the original T-72S, maybe a bit worse as result of the weight increase. 

Not the extruding steel casing at the gun mount

The tank features a new polygonal metal sleeve at the base of the gun barrel. The purpose of this design has not been revealed yet, but it might be an attempt to reduce oscillations when firing on the move. On some combat vehicles, such as the German Puma infantry fighting vehicle (IFV) and the Ukranian BTR-4, the gun barrel is enclosed in a metal casing in order to provide better stabilization when firing multiple rounds on the move.

Karrar MBT prototype: new armor is colored black, while the vehicle is painted grey

The armor protection has been improved by fitting a more modern ERA package to the tank. Previoulsy the T-72S was fitted with the Soviet-made Kontakt-1 armor. The new explosive reactive armor (ERA) covers the frontal aspects of turret and hull, while also protection the hull sides along the crew compartment. At the engine compartment and turret rear section, slat armor is utilized for protection against rocket-propelled grenades (RPGs). The turret sides are fitted with spaced composite armor modules.

Note the odd shaped ERA the glacis, LED headlights, driver's optics and the new gunner's sight

While the explosive reactive armor at the turret front and hull sides appears to be very similar to the Relikt ERA solution used on the T-90MS, the ERA package mounted at the glacis uses oddly-shaped ERA tiles, that are very thick, but have a rather small overall size. It is about twice as thick as the normal Kontakt-1 ERA used on the T-72S Shilden. This type of armor is somewhat reminiscent to the ERA used on Iranian M60 tank.

Most likely the reactive armor of the Karrar provides protection against RPGs, anti-tank guided missiles (ATGMs) with single-stage shaped charge warhead, as well as some degree of reduction in the penetration capabilities of APFSDS ammunition. It might also provide some limited protection against tandem shaped charge warheads, but that is not confirmed.

The T-90MS features ERA also at the turret sides

It must be noted that the latest version of the T-90MS also features explosive reactive armor covering the spaced side armor modules of the turret. On the Karrar such armor is not found, suggesting that it might be reverse-engineered by the Iranian military industry based on older photographs of the tank instead of being a proper cooperation between Iran and Russia. Alternatively Russia might have only offered the older version of the tank, which lacked the enhanced side protection. Two banks of six smoke grenade launchers allow the tank to hide while retreating.

RWS and coommander's sight of the Karrar MBT

The Karrar is fitted with a remote weapon station (RWS), which is coupled to an independent optic for the commander. It includes a thermal imager, a day sight optic (probably a CCD camera with zoom functionality) and a laser rangefinder. The weapon station is armed with a 7.62 mm machine gun and also includes a secondary camera located left to the armament.
This RWS desgin is also used on the T-90MS and on some products of the German company Rheinmetall, where it is known as main sensor slaved armament (MSSA), consisting of a heavy machine gun and a SEOSS sight.

Prototype fitted with the older generation RWS

Older photographs show the Karrar being fitted with a different RWS, which usually is armed with a Soviet-designed PKT machine gun, but it seems to lack the same advanced optronics of the newer design. This remote weapon station is also a lot more bulky, because the ammunition container is located at the side of the gun.

The Karrar MBT features an upgraded fire control system

The fire control system (FCS) of the Karrar has been significantly enhanced. Aside of the new indepent sight for the tank's commander, the main optics for the gunner have been replaced. The gunner's sight now features not only a day sight, but also a thermal imager for enhanced target detection and acquistion at night and in situations with reduced visbility. The origin of the new FCS is unknown, but the local industry has utilized the EFCS-3 from the Solvenian company Fotona in the past to upgrade the dated M60A1 and T-54 tanks. The Defense Industries Organization (DIOMIL) of Iran also offered the KAT-72 FCS as upgrade for older generations of T-72 tanks. Both these systems however lack thermal imagers and independent sights for the tank commander, suggesting that the Karrar utilizes a newly developed system - probably incorporating imported technology. Iran has been supporting the Syrian government, which operates T-72 tanks fitted with the advanced Italian TURMS system. Iran also has good relations with North Korea, from which Syria imported components of thermal imagers for upgrading older T-55 tanks.
A small searchlight, which probably can be rotated, is located next the gunner's hatch. The driver is provided with a new camera system next to his vision block, which contains two optics - probably a daysight CCD camera and a night vision optic. The tank also features new LED headlights. 

Suprisingly the Karrar appears to be one of the most advanced modernizations of the T-72 tank, albeit the performance and specifications of most components are currently unknown. If the engine was replaced - but there currently is no sources suggesting that this happned - the tank could be even better. It might be able it compare favourable to tanks such as the Russian T-72B3 and the Polish PT-91 Twardy in many aspects (such armor protection and firepower) - but in the end the crew performances matters just as much as the equipment.

Freitag, 10. März 2017

Leopard 2 projects

In April 2015 the German Army announced it's plans to increase the operational Leopard 2 fleet by 103 tanks. Since then not a lot has happened, as revealed in official documents and in newspaper articles from the Februrary of 2017. At least some of the tanks are currently owned by the German defence industry, so the government has to buy them back - but no contract has been signed within nearly two years of planning. The Leopard 2A4 main battle tank (MBT) is an improved version from the mid/late 1980s of the original Leopard 2 tank. By modern standards it has outdated armor, a short gun with inferior armor penetration and range, while lacking of modern electronics, optronics and relying on the more dangerous hydraulic systems instead of using electric drives. 

Leopard 2 tanks in long-term storage

Original reports from last year expected 84 of the new tanks to be upgraded to the Leopard 2A7 or the improved Leopard 2A7V configuration. The costs for buying and upgrading the tanks are expected to be about 760 million Euros, the contract might be signed before summer of 2017; if not the whole program might be delayed by another year due to the German elections in September 2017. The reason for the current delays is a disagreement between the two companies Krauss-Maffei Wegmann (KMW) and Rheinmetall. Current workshare plans see about a third of the work (and the money) going to Rheinmetall, but the company demands more. Rheinmetall acquired the military division of Maschiennebau Kiel (MaK) in 1990, which was responsible for manufacturing 45% of all German Leopard 2 tanks. Rheinmetall is also a major subcontractor for the main armament, delivering the L/55 smoothbore gun for the tank.
KMW on the other hand doesn't want to share any more work and money with the much larger competitor, which has decided to invade KMW's core business by offering Leopard 2 upgrade since 2010. The company has a much more specialized portfolio than Rheinmetall, pretty much offering combat vehicles and remote weapon stations (RWS) only.


Meanwhile the upgrade of fifty Leopard 2A6M to the so-called Leopard 2A6M+ configuration is under way. This is an inofficial name only, which is supposedly used to differentiate between upgraded and stock Leopard 2A6M tanks. After the upgrade the 2A6M+ designation will be dropped and all vehicles will be refered to as Leopard 2A6M. The commander's sight will be replaced by the new PERI R17A3 incorporating a third generation ATTICA thermal imager, which was first adopted on the Leopard 2A7 in 2014.

The Leopard 2A6M+ can be identified by the bulge for the ultracaps and the spaced armor above the SOTAS-IP system

The SOTAS-IP multi-media communication system from the French company Thales is installed in the Leopard 2A6M+. Aside of the Leopard 2A7 tank, it is also used on the Boxer armored personnel carrier (APC) and the Puma infantry fighting vehicle (IFV); it is also part of the IDZ soldier system. To deal with the increased power demands, the tank is fitted ultra capactiors, which can deliver energy faster and increase the stability of the electrical power supply. The Deugra fire supression system has been reactivated using the extinguishing agent DeuGen-N FE36 (for a certain period of time the fire supression system was not utilized due to the previous extinguishing agent violating environment laws). The upgrade also features new digital control panels for the crew.

At the IDEX 2017 military exhibition two variants of the Leopard 2 were present: Rheinmetall demonstrated a prototype or testbed of the, currently in development, Leopard 2PL tank, while KMW presented the Leopard 2A7Q, which has been refered to as Leopard 2A7+ or Leopard 2A7 QAT by numerous other sources. Rheinmetall is also delivering the Leopard 2RI to Indenonesia, which features greatly enhanced armor protection, air conditioning and other features.

Leopard 2PL with MSSA

The Leopard 2PL is an upgraded Leopard 2A4 tank meant for the Polish Army. It is based on the modular MBT Revolution upgrade, which has been renamed to Advanced Technology Demonstator (ADT). The tank features improved armor protection by adding thick AMAP composite armor modules to the turret, supposedly increasing protection level beyond the Leopard 2A5 level. New optics with a Polish-made third generation thermal imager and Jenoptik's electric turret drives are also part of the upgrade. Changes to the fire control system (FCS) allow the usage of the programmable 120 mm DM11 high explosive (HE) ammunition and the DM63A1 APFSDS round with temperature independent propellant and high penetration capabilties.
A new addition of the vehicle presented at IDEX 2017 is the MSSA (main sensor slaved armament) remote weapon station, which does not have it's own optics and is coupled to the commander's independent sight. It is not part of the upgrade of the Polish Leopard 2A4 tanks. The installation of the MSSA also means that the digital SEOSS sight is utilized instead of the PERI R17A3.
Rheinmetall is in the process of bidding for an upgrade contract of the Turkish Leopard 2A4 tanks, which suffered heavy losses in Syria - or at least ISIS wants us to believe that. The company is also part of a joint venture that is trying to get the contract for producing the new Turkish Altay MBT.

Leopard 2A7Q at the IDEX 2017

The Leopard 2A7Q is a version of the MBT made for the Qatari Army. It is based on the Leopard 2A7+ demonstrator from KMW, thus it includes a number of changes currently not found on the German Leopard 2A7, such as the additional hull armor kit, the passive bomblet and top-attack protection on the roof and the FLW 200 RWS. The Leopard 2A7Q is fitted with a modified APU, which is even running when the vehicle is standing still in order to power the air conditioning system. The Barracuda camouflage system of the Leopard 2A7Q is having longer skirts, which reduces dust clouds when driving through the desert. According to unconfirmed rumors an unknown nation has purchased (or ordered) a large number of Leopard 2 tanks from KMW. An indicator for the validity - or maybe the origin - of this rumor is a sheet of paper being attached to the Leopard 2A7Q at IDEX 2017, which contained the text "SOLD".

After the purchase and upgrade of the Leopard 2A4 tanks, the German Army will have 103 Leopard 2A7(V) tanks in service. 48 Leopard 2A6M(+) and 152 Leopard 2A6 will supplement them. Seventeen Leopard 2A5 will remain at the combat training centre, being the last vehicles fitted with the short-barreled L/44 gun. Thirty-two Leopard 2 tanks (including 20 of the re-purchased Leopard 2A4) tanks will be kept for conversion to combat engineering vehicles, bridge-layers and other variants. Two Leopard 2A5, two Leopard 2A6, two Leopard 2A6M and one Leopard 2A7(V) tank will remain at the German military procurement office, the BAAinBw as reference and for tests, trials aswell as upgrade proposals. On the long run all tanks should be converted to a single version in order to keep logistics at a reasonable level.

For the Leopard 2A7V many technologies and features have been considered, but the only known demonstrator from KMW is a rather conventional upgrade. All Leopard 2A7 tanks are meant to be upgraded to the 2A7V configuration until 2022. What exactly will be changed is unknown, but apparently the engine will remain the dated MB 873 Ka-501 from MTU. It's very reliable and fuel efficient, but bulky by modern standards. Instead of replacing the engine, the powerpack and drivetrain will be modified - in particular the transmission and the side drives - to improve the mobility of the tank. If this allows to reach the original requirement for the Leopard 2A7V - regaining the mobility of the 10 tons lighter original version of the Leopard 2 - is questionable at least. The drivetrain also will be strengthened to deal with the high weight, while the APU's power output has been raised to 20 kilowatts.

The Leopard 2A7+ prototype includes a hull armor kit

The Leopard 2A7V will feature enhanced armor protection, which might be limited to the installation of a hull armor kit. However the basic Leopard 2A7 is already fitted with connectors, which allow fitting additional armor packages to the sides of the hull and turret when required. The composite armor modules at the upper front plate (the glaics) are about 45 mm thick; including the slope this boosts armor thickness from aproximately 328 milimetres to 697 milimetres. The relatively thin glacis relies on it's extreme slope; against highly sloped armor most shaped charge warheads fail to fuze, while APFSDS penetrators have a tendency to break, which greatly reduces the penetration performance. At the hull nose and lower front plate, the increase in armor thickness is estimated to be about 200 to 300 milimetres. This is a considerable improvment compared to the original Leopard 2 hull.
While thickness and shape are similar to the MEXAS-H hull armor of the Strv 122, Leopard 2A5DK, Leopard 2A6HEL, and Leopardo 2E, the size and locations of the mounting bolts has been altered. This might imply a change in armor composition, a more modern version (using newer AMAP technology) would offer better resistance to penetration or lower weight for a given protection level.
The ATTICA thermal sight will replace the WBG-X

The Leopard 2A7V upgrade is said to include improved main optics for the gunner - the old first generation WBG-X thermal imager would be replaced by a third generation ATTICA device. The SPECTUS sight from Airbus (originally developed by Zeiss, but the military divison was sold to Airbus) provides the driver with IR night-vision aswell as a thermal image. A new camera system for better situational awareness was fitted to the KMW demonstator vehicle at Eurosatory 2016. The FLW-200 remote weapon station is also expected to be part of the Leopard 2A7V upgrade. It can be fitted with (heavy) machine guns and automatic grenade launchers. Denmark supposedly will upgrade at least some of it's tank to a similar configuration.

Last year the company Rheinmetall announced, that the new L/55A1 gun will be delivered to the first costumer in 2017. According to the company, the launch costumer will be the German Army, implying this gun will be part of the Leopard 2A7V upgrade. The L/55A1 smoothbore gun is an enhanced Rh 120 L/55, which can handle higher pressures: This will result in an increase in performance (penetration and range) by 20% according to earlier data from the manufacturer.

The new 130 mm smoothbore gun from Rheinmetall

On the long run the Leopard 2 and the French Leclerc MBT will be replaced by the Main Ground Combat System (MGCS), a next-generation tank for which Rheinmetall developed a 130 mm smoothbore gun with 50% improved penetration capabilties. The MGCS is a co-development between Germany and France, but other countries are expected to join the development. Rumors - or speculation from random forum users - suggests that the turret might be developed in France, while the hull would be made in Germany. These speculations seems to be rather questionable, although the French know-how in autoloader-design might be an important aspect for the MGCS. The conception phase for the Main Ground Combat System is expected to end in 2017, after that the development of first prototypes would start. In the timeframe from 2025 to 2030 the first vehicles should be ready.

Samstag, 21. Januar 2017

Leopard 2 in Syria - part 2

Yesterday a new video was released by ISIS terrorists showing a bunch of destroyed main battle tanks (MBTs) and armored personnel carriers (APCs) near the Syrian city of Al-Bab. This video however has proven something, that I understimated a certain weapon. Not anti-tank guided missiles (ATGMs), not improvised explosive devices (IEDs). A much older weapon: propaganda. The same weapon that turned the Tiger heavy tank - a rather mediocre design of it's time - to a supposed super tank, that still is being worshipped by some individuals today. However the propaganda worked, invoking a Tiger-phobia on the side of the allies.

Now, what exaclty has happened? A new video showing the exact same area that the first few videos were showing. The destroyed or damaged tanks are probably all identical to the tanks already shown in earlier videos, that have been covered by numerous news articles and blogs. Still some people start writing articles in a sort of kneejerk reaction, claiming that these are newly defeated tanks and that the Turkish Army is just poorly trained or the Leopard 2 is a poorly designed tank, incapable of competing on the same level as the tanks of other countries (even though this is not tank-vs-tank warfare...). This again leads to people to come and reply or spread the articles, which are pushing for their own agenda. "The T-90 is so much better, only one was penetrated!", "All people who think the Leopard 2 is a good are Nazi-tank fanboys" and "The Abrams/Challenger 2/T-84 is an inpenetratable super tank". People love to ignore the fact that the Turkish Leopard 2A4 is fitted with out-dated armor, possibly still the first generation of armor technology introduced with the original Leopard 2 in 1979. The fact that the Turkish Army was purged after the failed coup attempt - in which most tank units were equipped with Leopard 2A4 tanks - is intentionally ignored.

So what exactly has happened to the Leopard 2 in the past month in Syria? Well, apparently not much in that area. ISIS was only interested in spreading images from already destroyed tanks - this might mean that there are no newer encounters that were video-taped.

Leopard 2 tank wrecks in Syria
The first Leopard 2A4 tanks of the Turkish Army were destroyed or at least disabled in combat already in December. Above are screenshots from one of the very first combat encounters, below are captures from two different propaganda videos - all showing the same two destroyed tanks. Well that's propaganda, pretending (by using different camera positions and filming on different days) to have destroyed six tanks, while in reality only two were destroyed (or rather one was destroyed, while one was apparently rendered immobile and abandoned).

An ATGM penetrated the roof of this tank
The image above shows a tank was hit by an ATGM at the roof. There are at least three different scenes from different videos showing this tank. It actually might be four, but the image quality of one is so bad, that it couldn't be clarified without doubt. This shows again how the terrorists' propaganda tries to inflate kill numbers in an attempt to demoralize the enemy. They supposedly even filmed the tank at different times of the day, so that the mood of light changed.

Blowing up captured tanks
The terrorists are known to have captured up to three tanks, of which one had a track issue. So what to do with a tank that cannot be utilized by the own forces? Blow it up in a propaganda video, pretending that it was an enemy tank destroyed in combat.

Victims of a large explosion: airstrike or blown up after being abandoned
Supposedly at least one captured tank was destroyed by an airstrike from a Turkish F-16. A photo showing a Leopard 2A4 with turret popped of the hull was shared on Twitter in December 2016. While it is not exactly confirmed that this tank is one of the two destroyed tanks above, all vehicles in above photo show damaga typical for airstirkes or large explosive charges being placed inside the vehicle. This can be seen by locking at the front of the Otokar APV (engine compartment blown off) and the excessive damage caused to the frontal Leopard 2.
One can only speculate about the exact fate of this tanks. Were they abandoned and then destroyed by an airstrike? Were they captured by ISIS and then destroyed by Turkish forces? Did the terrorist blow them up for a propaganda video?

Overview with text by militaysta
That's why speculating about how awful or how good some military unit perform just based on photos of wrecks doesn't make sense. Who knows how many hits the tank took before ending there? Or maybe the tanks didn't even take any damage but broke down before combat. Who would know based on a wreck of a tank?
Snafu Solomon reblogged an interesting article from DieselPunkIsDad on survivability bias. While this term doesn't exactly apply to the topic, it clearly shows the same problem: people are judging the peformance of a combat vehicle, a military unit or even a whole nation based on a biased subset of encounters. The Battle of Crete was a horrible failure from the perspective of the Nazi-German Army, which abandoned the tactics of airborne invasion via paratroopers after it. From the perspective of the Allies, who were unaware of the German losses, the airborne invasion was suddenly a highly effective tool of warfare - that happens when only a subset of data is considered. How many videos out there are showing an Iraqi or a Saudi Abrams tank getting hit by an ATGM, while sitting in the open without (mechanized/motorized) infantry support? Everytime such a video appears, someone comments on how bad said vehicle/persons are doing and how they are essentially getting slaughtered. What is ignored in this context is that the terrorists will only show your successful attacks - that's how propaganda works. But how many times do their attacks fail by missing the target, failing to penetrate the armor or being discovered and killed?

Older informations on Turkish losses via Reddit

So what is the conclusion of this post? Well, probably that one should keep calm and take some time to think about what is shown by a source and what the motivation for showing this is. Based on the videos and earlier reports of Turkish losses, there seem to be no recently destroyed tanks at this specific area near Al-Bab. This could have several different reasons, but speculations without sources won't lead to much.
According to older Turkish sources, a total of ten Leopard 2A4 tanks, one M60T Sabra and four other vehicles were disabled or destroyed in the area around Al-Bab. One Leopard 2 had an issue with the tracks and the situation of one tank is unknown (supposedly this tank is among the ones captured by ISIS). Two tanks were damaged by IEDs, one of them heavily. A further tank was damaged by a mortar attack, while the other five Leopard 2A4 tanks were damaged by ATGMs - back then not a single tank was listed as destroyed by ATGMs. Earlier sources from about a week before the losses were leaked/published via Twitter claim that fifteen M60T Sabra tanks, three M60 tanks and three Leopard 2A4 were hit by ATGMs. One of the M60 tanks and three Sabras were total losses. Supposedly ten soldiers died in Turkish tanks at this time. The fact that no new tank wrecks appeared in the area from Al-Bab doesn't mean that Turkey hasn't lost more tanks since then - but it also doesn't directly confirm any losses at other places.

Turkish sources claim that between the 8th and 18th January 192 air raids and firing 2,196 rounds of artillery, tank and mortar ammunition resulted in the death of 1,362 enemies, a further 168 were wounded. As always these claims haver to be taken with a grain of salt, as there is no proof for any of these claims and kill figures of airstrikes and artillery are known to be exaggerated quite often. Still if true, one shouldn't pretend that the Turkish Army is so bad and the "Arabs are horrible at war" meme applies (not to mention that technically Turks aren't Arabs). Yes, the first Leopard 2 tanks were employed in a horrible way and thus destroyed. But maybe at least some common NATO training standards are met and result in some better performance after the initial shock.

Mittwoch, 18. Januar 2017

Early M1 Abrams composite armor

On the TankNet forums, a user with the nickname "whelm" has posted drawings from a formerly classified document on the earliest iteration of the US M1 Abrams main battle tank (MBT). He got this document from Vollketten, a user with accounts at the Sturgeon's House forum, the WoT forum and other places. It details the armor layout of the tank, showing were the Burlington composite armor is located and how it is specifically implemented on different areas.

The name of the document

Burlington special armor, also known as Chobham armor, is a type of composite armor developed in the United Kingdom by the FVRDE from the late 1960s onwards. It consists of a number of sandwich plates - also called biscuits - which are mounted in a spaced configuration. It is understood that these sandwich plates work as a type of non-explosive reactive armor (NERA), by using an elastic interlayer located between two metal plates (usually steel or alumininum). On impact the rubber will compress to the point of maximum compression, until expanding again and bouncing back. This will move more material into the path of penetration and also shatter thin and fragile projectiles, such as the shaped charge jets created by high-explosive anti-tank (HEAT) warheads commonly used on anti-tank guided missiles (ATGMs) and rocket-propelled grenades (RPGs). Essentially NERA works like explosive reactive armor, but with a lot less plate movment, as it only reuses the energy from the impacting projectile, instead of using an external energy source (such as the detonation of an explosive layer) to move the metal plates.

The location of the special armor on the M1 Abrams MBT

The special armor covers the frontal arc of the tank only, with an exception being the sides of the turret bustle. The lower front plate (LFP) of the hull is fitted with composite armor, the upper front plate, also known as glacis plate, however relies on conventional steel armor with high sloping. The gun shield and turret front, as well as complete turret side armor and the frontal two/four side skirt segments are protected by Burlington special armor aswell.

The frontal hull armor
The lower fornt plate of the M1 Abrams' hull consists of an array of NERA sandwich plates, which however only cover about half of the complete armor volume. The other half of the armor thickness is occupied by a mounting bracket for the NERA sandwich array and conventional steel armor. When hitting the hull straight on, the projectile has to pass through the exterior steel layer, four sandwich plates and then the thick inner steel plate.

The armor layout of the gun shield
The special armor of the gun shield of the Abrams follows a similar design as the hull armor, however there is no mounting bracket. The gun shield itself also does only include a rather thin backplate, however there is a thick steel plate located behind the gun shield, which might be connected to the trunnion plate. When hitting the tank straight without any oblique angle, the penetrating projectile again has to pass through four sandwich plates.

The side armor of the turret bustle
 The side armor at the turret bustle seems to be the most interesting aspect of the tank, as it not only features a sloped NERA sandwich array and a mounting bracket as seen on the lower front plate armor array, but it also features a multi-layered backplate consisting of two steel plates with another material located between them. The exact naturre of this material is unkwnon, but it could be an application of ceramic as armor material. Using ceramic armor as part of the backplate in order to absorb the leftover penetration power of a projectile, that was damaged by (N)ERA sandwiches, has been suggested and patented by the Franco-German institute in Saint-Louis; it is believed that the armor used on the Leopard 2 and Leclerc might follow the same concept.
However there is no exact proof that said material is ceramic; other possibilities include glass and silicia, which have been tested by the US Army's Ballistic Research Laboratory in the 1950s and 1960s as part of the siliceous cored armor for the T95 medium tank and the XM60 MBT. In theory the material also might be a type of glass-reinforced plastic or aluminium, as used on the early models of the Soviet T-64 and T-72 tanks.

Side skirt armor
The sides skirts of the M1 Abrams consists of a four or five layer sandwich, which is spaced from the homogenous steel base hull armor. The outermost plate is apparently a steel plate, followed by what is believed to be alternating layers of elastic material and metal. On the left hull side only the frontal two skirt elements are fitted with special armor, which is required for protecting the crew and fuel tanks along the 60° arc (±30° from the tank's center line). On the right hull side, the first four side skirt elements are made of special armor, which is required to also protect the hull ammunition storage that is located behind the turret ring at the right hull side.

Burlington armor array for the British Chieftain Mk. 5/2 MBT
Unfortunately there is no image showing the frontal turret armor, but given that we know the layouts of the frontal hull armor, the gun shield armor array and the turret side armor, there is not much reason to doubt that the frontal turret armor will look a lot differently. In general the Burlington composite armor used on the M1 Abrams is a further evolution of the British designs from the 1960s and 1970s. Thanks to nowadays declassified documents, it is a secured fact that the UK shared it's armor research with the United States and the Federal Rebuplic of Germany during the Cold War. Thus we can expect the early armor arrays used on Leopard 2 and Challenger 1 to look very similar.

Merkava armor

Other countries have developed their own versions of NERA sandwich arrays in the past. The Soviet Union adopted a very similar armor layout in 1985. Leaked Chinese armor arrays from research papers and CAD models show a very similar conception, using NERA sandwich arrays held by mounting brackets in front of thicker and multi-layered backplates. Photographs of damaged Merkava tanks reveal a similar armor concept/technology.

Chinese composite armor arrays
More modern versions of the M1 Abrams and other tanks are still following this general armor design concept, however sometimes more complex arrays with additional layers and elements are used. A common design principle according to Dipl.-Ing. Rolf Hilmes, who formerly worked at the German BWB, and according to a presentation from the British Defence Science Technology Laboratory (DSTL), is to incorporate a further heavy layer in front of the armor array, which servers to disrupt (shatter/break) the projectile, before the fragments enter the NERA array. There are different options to implement this armor, however a common way is to use heavy ERA (such as the Kontakt-5 ERA and Relikt ERA used on Soviet/Russian MBTs) or thick NERA plates (as featured on the Leopard 2A5 and subsequent versions).

Turret armor of a Soviet T-72B MBT
Photographs from US Abrams tanks damaged in the Gulf War and in the Invasion of Iraq, show that in general the armor layout of the Abrams has not been altered drastically. Most likely the materials have been improved and the thicker back plates have been replaced by mutli-layered arrays including ceramics and other materials.

M1 Abrams' side skirt penetrated during the Invasion of Iraq
A known addition to the side armor of the M1 Abrams' turret is at least a new spaced armor array, which is mounted on coil springs. The spaced armor is made up of three rather thin, multi-layered sandwhich plates. Most likely the coil springs are compressed, which would enable greater force being used against a penetrating projectile.

Destroyed M1A1 HA with exposed armor elements
A more detailed coverage of modern armor technology on this blog is planned for the future.