The market for wheeled 8x8 is not saturated (yet)

There are multiple ongoing procurement programs in Asia and Europe regarding the adoption of modern 8x8 wheeled vehicles for use as ambulance vehicles, armored personnel carriers, infantry fighting vehicles, mortar carriers and other roles. While Australia and supposedly also Japan are looking for a new 8x8 vehicle, Germany is upgrading the Boxer MRAV and adopting further variants. The British Army is requiring the largest number of new 8x8 vehicles, but various Eastern European countries including Bulgaria, Romania, Slovakia and Slovenia are also interested in new wheeled combat vehicles. This means that vehicles such as the Advanced Modular Vehicle (AMV) from Patria, Artec's Boxer MRAV (multi-role armored vehicle), the Pandur II and Piranha V from General Dynamics European Land Systems, and "underdogs" on the international market such as the Terrex 3 and the French VBCI might be adopted in larger numbers by the militaries of multiple countries in the near future. The US-based company Textron and a Turkish company are also bidding in some tenders.

The Boxer CRV and AMV-35 are being evaluated during the LAND 400 program

A key factor for the developments on the global 8x8 vehicle market might be the decision of the Australian military in the LAND 400 program, which is expected to be made in early 2018. The phase 2 of LAND 400 included four of the most advanced current 8x8 vehicles - variants of the Boxer, the Patria AMV, the LAV 6.0 and the Sentinel (Terrex 3) - i.e. vehicles that are relevant for any military considering to buy a new eight-wheeled armored personnel carrier (APC), infantry fighting vehicle (IFV), or Combat Reconnaissance Vehicle (CRV). Various other vehicles such as the VBCI 2 were initially also offered to the Australian military, but the bids were withdrawn when it became clear that a solution based on military of the shelf (MOTS) components was favored.

Currently only the Boxer CRV and AMV-35 remain in the competition. Based on the prototypes being tested in Australia, it appears that both consortia are betting on very different strategies. While Rheinmetall showcases the Boxer CRV as a very customizable high-end offering including all of the latest gadgets (including active protection system, remotely operated weapon station, anti-tank guided missile launcher, accoustic sniper detection system, laser warners, situational awareness system, etc.), the BAE-Patria joint-venture focuses with the AMV-35 on a more affordable offering, presumably trying to impress with a higher cost effectiveness compared to the Boxer.

The VBCI was already tested in the UK during the FRES project

The British military is considering to buy the Boxer MRAV for the Mechanized Infantry Vehicle (MIV) program, as mentioned by various news sources over the last year. The number of vehicles to be purchased within the £3 billion project is varying by source from just 300 up to 900. While there are several options offered by the arms industry to the UK, the British Army has not yet decided wether it wants an open tender or prefers a direct government-to-government (G2G) deal with Germany for buying Boxers. The advantage of open competition is that the best solution can be found, be it the overall cheapest solution, the most capable vehicle or the jack of all trades. On the other hand the budget of the British Army has shrunken dramatically - and is expected to shrink further thanks to the Brexit - so that English newspapers suggest that an open evaluation of multiple contenders might be too expensive (and with Brexit potentially resulting in additional tolls to be paid also too time consuming). A decision wether to buy the Boxer MRAV or have an open competition is expected at the end of 2017.

By painting a Boxer in the Union Jack pattern, Rheinmetall reminds the UK of the British participation in its development

If the Boxer CRV is chosen by the Australian Army over the AMV-35, this could have positive effects on its chances in the United Kingdom according to German speculations. First of all, there would be greater interoperability between the ground forces of two commonwealth nations, something that is assumed to be desirable. Furthermore the British Army could argue that the Australian tests already have proven the superiority of said vehicle, circumventing open competition in order to rush a vehicle in service. While this in general would also work with the Patria AMV, there are no news reports on the UK Ministry of Defence (MOD) thinking about purchasing the AMV instead of having an open tender.

The Boxer RCH 155 mounts an AGM instead of a mission module

Supposedly the UK is also looking for a self-propelled artillery gun (SPG) variant of the vehicle purchased under the MIV program. The Boxer MRAV is the only modern 8x8 wheeled solution that has been showcased with a 155 mm gun, i.e. the artillery gun module (AGM) from Krauss-Maffei Wegmann (KMW) mounted instead of a mission module. The long L/52 gun barrel of the AGM and the high level of protection provided by the Boxer's drive module makes this solution in some aspects better than the current tracked AS-90 self-propelled gun.

At the DSEI 2017, various manufacturer's presented their potential offers for the MIV program including the Piranha 5 from General Dynamics, the Patria AMV XP, the VBCI from Nexter, and  two different Boxer variants from Artec. Rheinmetall painted one Boxer with the Union Jack, while KMW focused on showcasing the modularity of the vehicle with an IFV variant. Aside of the benefits that the modular design enables, the German companies also mention that the UK would have full intellectual property of the Boxer due to its history (being designed in a multi-national project that used to include the UK), allowing them to create and sell their own vehicle variants without any interference from the Germany.

The Japanese military has presented a prototype of their indigenous 8x8 APC

Supposedly Japan is also interested in adopting a more modern 8x8 vehicle compared to its old and lightly protected Type 96 armored personnel carrier. Mitsubishi has already created and showcased a prototype vehicle based on components from the Type 16 Maneuver Combat Vehicle (MCV). However Japan is known to have a somewhat deep military cooperation with Australia, which is why the country of islands is observing the decisions LAND 400 program - apparently some sources suggest that the Japanese Ground Self-Defence Force (JGSDF) might be interested in having a certain degree of interoperability with the Australian Army.

According to the German website hartpunkt.de, defence industry insider sources claim that the Japanese military requested informations on the performance of the Boxer MRAV, specifically regarding its armor protection and modularity. It is worth mentioning that in July 2017 Germany and Japan signed an agreement for cooperation in the arms industry/technology sector. Back then it was reported that Japan was primarily interested in German protection technology, i.e. technologies regarding special armor and potentially also active protection systems. The Japanese news service Asahi Shimbun specifically mentioned that this technology was meant for a "troop transport carrier" (i.e. an APC or IFV). Negotiations regarding the agreement started already in 2015; both countries agreed to not disclose the exact content of the contract. In September 2017 a German-Japanese military technology forum was held in Tokio, which included more than thirty German defence companies.

The Boxer A1 saw combat in Afghanistan

The Bundeswehr recently decided to upgrade all current Boxers to the new A2 configuration, which features changes to both the drive module and the mission module, such as installing a new satellite communication system, fitting an improved driver vision systems, adopting a new storage arrangement, making changes to the cooling and exhaust system of the vehicle, improved protection and adding a secondary control panel for the FLW 200 remote weapon station. A contract for the upgrade of 124 armored personnel carriers, 72 ambulance vehicles, 38 command post vehicles and 12 driver training vehicles was announced in July 2017. All new Boxers that have been and will be ordered by the German Army will also be delivered as Boxer A2 or in a follow-up configuration.

According to the German website hartpunkt.de, the German Army plans to use the Boxer as base for a heavy vehicle for the joint fire support team (JFST) units. This Boxer JFST variant would be equipped with a high quality sensor package, probably the mast-mounted BAA II surveillance and reconnaissance platform from Hensoldt Optronics, that is already being used on the light JFST vehicle on the Fennek 4x4. Rheinmetall as member of Artec also offers a number of sensor platforms for ground vehicles, such as Vingtaqs II system that is operational with the Norwegian and Malaysian militaries. Alternatively the greater payload and internal volume of the Boxer could be used for a larger sensor package, which could in theory also include a larger ground surveillance radar unit. A Fennek can carry only the equipment for either ground-to-ground coordination or ground-to-air coordination, each Fennek JFST vehicle is hence specialized on either role. The Boxer has enough room to hypothetically carry the equipment for both tasks, although it hasn't been decided if a single Boxer should be used for both roles. The Boxer was chosen over a competiting design based on the PMMC G5. Unlike current JSFT solutions from the UK and the United States, the Boxer is not expected to be fitted with a direct fire gun or anti-tank missiles. There is a requirement for about 20 to 30 Boxer heavy JFST vehicles.

JFST vehicle based on the Fennek 4x4

Currently there are also plans for a fire support variant of the Boxer for the Jäger units, according to Inspector of the Army Jörg Vollmer, who is in charge of the German Army. The plans see the fifth (heavy) company of each battalion receiving Boxers with direct fire guns.

The exact type of armament has not been specified, but given earlier reports it seems likely that the interest is focused around the 30 x 173 mm calibre, i.e. the same MK 30-2/ABM main gun as used on the German Puma infantry fighting vehicle (IFV). The vehicle might as well be fitted with a launcher for the Spike-LR anti-tank guided missile (ATGM).

A so called "PuBo" - Boxer with RCT 30 (Puma turret)

Currently the German military is said to consider different turret options and still has to decide wether a manned or an unmanned system is favored. It is understood that the choice - if the informations regarding a 30 mm calibre are correct - is limited to KMW's Remote Controlled Turret 30 (RCT 30; essentially a Puma turret) and the Lance Modular Turret System from Rheinmetall. Both these turrets have their own unique advantages and drawbacks. The RCT 30 is already in service with the German military and hence provides advantages in regards to training, logistics and spare parts. Furthermore it appears to be more heavily armored than the Lance turret, as it is can be fitted with additional roof armor against shaped charge bomblets; while Rheinmetall manufactures similar armor, there hasn't been a prototype of the Lance turret featuring such improved roof armor. The unmanned nature of the turret makes it smaller and lighter. However unmanned turrets have worse situational awarness than their manned counterparts.

A Boxer with Lance turret being demonstrated at a Rheinmetall facility in Germany

The Lance turret on the other hand is available in either unmanned or manned configuration, but it seems likely that only the latter is being considered, as this was already installed on several Boxer prototypes including the Boxer CRV. It is larger than a Puma turret and also heavier, when fitted with a similar armor package; however in theory it can also adopt larger calibre guns such as the 35 x 228 mm Wotan 35 chain gun. The Lance turret suffers from being fitted with several Rheinmetall-made components, which have not been adopted yet by the German military, albeit the modular construction might allow to change them. For example the turret is fitted with either one or two stabilized electro-optical sensor systems (SEOSS); one for the gunner (and one for the commander respectively), but the German Army relies on optics from Hensoldt Optronics for the Puma and several other combat vehicles.

The Belgian Army operates several Piranha DF90 fire support vehicles with 90 mm gun

In theory the German military could choose a lighter or heavier weapon station from various manufacturers. Just looking at the offerings from the two companies involved with producing the Boxer MRAV shows a wide variety of possible alternative armament options. Krauss-Maffei Wegmann showcased the FLW 200+ on the Boxer a few years ago, which is an enhanced variant of the currently used FLW 200 remote weapon station (RWS),  that can accept the 20 mm Rh 202 autocannon with 100 rounds of ammunition. The 500 kilograms heavy FLW 500 RWS can accept 30 mm autocannons such as the M230LF chain gun from ATK, a coaxial 7.62 mm machine gun and an optional missile launcher. Rheinmetall has developed the Oerlikon Fieldranger 20 RWS, which is armed with a 20 mm Oerlikon KAE autocannon; however this is not chambered in the 20 x 139 mm calibre as the Rh 202, for which the German Army should still have lots of ammunition - instead it uses the slightly less powerful 20 x 128 mm calibre.

Given that the new Boxer variant is meant as a fire support vehicle, one could wonder why the armament choice is supposedly focused on the 30 mm calibre, when other vehicles of the same type are often fitted with larger guns. E.g. the Belgian Army has adopted a number of Piranha IIICs with a 90 mm Cockerill gun for direct fire support, while a Rosomak prototype was fitted with the Cockerill 3105 turret. The Boxer with a much higher maximum gross vehicle weight - the latest available variant can support up to 38.5 metric tons and can be fitted with a 800 horsepower engine - should have no issues accepting a low-profile turret with a 120 mm smoothbore gun (such as the 120 mm L/47 LLR from Rheinmetall).

Aside of the exact turret choice, a number of other questions remain. A key question revolves around the role of the Jäger (light mechanized/motorized infantry) compared to the Panzergenadiere (mechanized infantry). Traditionally only the Panzergrenadiere are making use of infantry fighting vehicles, while the Jäger are limited to "battle taxi" style vehicles, which also affects the doctrines of these units. However putting a gun on an armored personnel carrier (APC) doesn't mean that it has to be employed like an IFV. Another decision yet to be made is focused on wether the Boxer fire support variant will carry a dismount squad or not. If a dismount squad is carried, it needs to be smaller in order to compensate for the ammunition storage, the gun operator(s) and the turret basket (in case a manned turret is chosen). Regardless of the decision, a contractt is not expected to be made before 2019. Then the Boxer fire support vehicles could enter service in 2021. A total of about 100 vehicles is required based on the current amount of German Boxer APCs.

The Vilkas is a Boxer IFV variant with the Samson Mk 2 RWS

The Bulgarian military is planning to purchase about 600 new 8x8 vehicles in several different variants for three new battlegroups. Among the demanded variants are also a mortar carrier and an infantry fighting vehicle. Supposedly the bidding process for this military procurement started already in May, with six vehicles being offered to win contract worth more than €500 million Euro. Artec is offering the Boxer, despite the fact that currently no operator has ordered a mortar carrier variant and not a single prototype of this is known to exist - the modular design however would enable a fast creation of such. It is also not known which turret will be offered for the IFV variant.

While the Boxer MRAV is extremely expensive compared to other solutions - in Lithuania the initial offer was claimed to be more than twice as costly as the Stryker ICV proposed by General Dynamics - the vehicle's superior performance (specifically the higher level of protection) resulted in the Lithuanian Army opting for it. The military prefered the Boxer MRAV, the politicans wanted a cheaper solution. In the end the Vilkas variant of the Boxer, mounting the cheaper and slightly less capable Samson Mk 2 RWS instead of the Puma's RCT 30 turret, was chosen.

General Dynamics European Land Systems (GDELS) offers the Piranha V vehicle family. An IFV variant of the Piranha V fitted with Rafael's Samson Mk 2 RWS was demonstrated on the 27. April at the Military Poligon Tylbleto in Bulgaria. The demonstration lasted three days and included live firing tests with the 30 x 173 mm Mk 44 Bushmaster II gun. The Samson Mk 2 RWS features two separate set of sights, a 30 mm autocannon, a coaxial 7.62 mm machine gun and a pop-up launcher for two Spike-LR missiles. It was also fitted to various IFV prototypes provided to the Czech Republic.

 

Patria AMV with 120 mm NEMO mortar system

While KMW as part of Artec is suggesting the Boxer to Bulgaria, the French company Nexter - a joint-partner of KMW - is offering an unknown configuration of the VBCI or VBCI 2. While not produced yet, Nexter already showcased scale models of a mortar carrier variant of the VBCI back in 2013. These models featured a large roof hatch with a two-piece door atop of the rear compartment. Inside the rear compartment an unspecified semi-automatic 120 mm mortar - similar to RUAG's Cobra mortar and the MO 120 mm R2RM from TDA Armaments - is mounted. As IFV the VBCI 2 can be fitted with a 25 mm autocannon in a one-man turret or with a two-man turret mounting a 40 mm CTAS gun. In theory unmanned turrets and other calibres are also available, but they have not been fitted to known prototypes of the VBCI 2.

Patria is offering versions of the Armored Modular Vehicle (AMV), although more details have yet to emerge. The wide userbase of the AMV has resulted in various different variants, so often multiple AMV versions are available for the same role. I.e. there are infantry fighting vehicles based on the AMV mounting the Hitfist turret from Leonardo (after acquiring Oto-Melara), the LCT30 turret from Denel Land Systems, and the BMP-3 turret, while prototypes were equipped with the unmanned MCT-30 turret from Kongsberg, the E35 turret from BAE Systems and the new 40 mm CTAS-armed turret of the Warrior WLIP upgrade. Likewise there are multiple 120 mm mortar variants with the Polish Rak mortar, the NEMO turret and the AMOS turret, while South-Africa has ordered a 60 mm breech-loaded mortar turret for some of its AMVs. 

Supposedly two further competitors are interested in getting a deal for equipping the new Bulgarian battlegroups: Textron and an unnamed Turkish company. There is some confusion regarding Textron here: Textron is not known for offering 8x8 vehicles, although it is not directly specified that a 8x8 vehicle is required. The US company was contracted to deliver about 17 M1117 Guardian armored security vehicles (ASVs) to the East European country in 2014; a further batch of ten vehicles was ordered in mid-2017. According to the Bulgarian news website dnevnik.bg, Textron and Rheinmetall have partnered to offer an unknown 6x6 vehicle for local production in Bulgaria.

As for the Turkish contender, this most likely is either FNSS offering a variant of the Pars or Otokar offering a variant of the Arma. Given the recent political tensions between various European countries and Turkey, it seems unlikely that a Turkish contractor would be chosen - the Czech Republic rejected all Turkish tracked IFVs due to the instable political relations.

The Scipio IFV

Two years ago in 2015, the Slovakian Army ordered about 30 Rosomaks (a Polish variant of the Patria AMV) fitted with the locally made Turra 30 turret from EVPÚ. Apparently the contract was scrapped according to different reports, which is why Slovakia has shown interest in buying a total of about 100 - some sources mention a lower number of only 81 - new 8x8 vehicles. Furthermore a total of 404 modern 4x4 vehicles are required by the army. The official requirements for the procurement project are not known, but they include a larger number of contenders. Deliveries of the first vehicles are expected to start in 2018 and last until 2029; it is however possible that the earlier date is only valid for the 4x4 armored cars.

The Corsac 8x8 is an IFV based on the Pandur II

General Dynamics European Land Systems is understood to offer a variant of the Pandur II. The Pandur II is an evolution of the Austrian-designed Pandur I, that is currently only manufactured in other countries. The militaries of the Czech Republic, Indonesia and Portugal operate various versions of the Pandur II. Due to its relatively low weight - the currently procuded models have a combat weight of only 24 metric tons - the overall level of armor protection is rather limited. While fitting applique armor allowed to meet the STANAG 4569 level 4 requirement for ballistic protection, i.e. all-round protectiton against 14.5 mm AP ammo fired from close range, the protection against mines was rather limited. Only in October 2017, the Czech military annonced that the latest 20 Pandur IIs in the mobile command post variant have managed the qualification for STANAG 4569 level 4b mine protection, after being fitted with the new BOG-AMS-V seats.

Last year GDELS presented a variant of the Pandur II co-developed with the Slovakian MSM Group, which is known as Corsac and features the same Turra 30 turret as the Scipio, mounting a 30 x 165 mm 2A42 autocannon, a coaxial MG and two 9M113 Konkurs (AT-5 Spandrel) ATGMs. However this armament can be replaced by Western alternatives such as the 30 x 173 mm Mk 44 Bushmaster II gun from Aliant Techsystems and Rafael's Spike-LR ATGM.

The Corsac IFV is powered by a 450 hp Cummins ISLe HPCR diesel engine and has a combat weight of only 19.8 metric tons, which is apparently related to the armor package fitted to the prototype. Top speed is quoted as 115 kilometres per hour on roads, but the vehicle is amphibious and can swim at a speed of up to 10 kilometres per hours. The basic ballistic protection reaches only STANAG 4569 level 2, but applique armor kits for level 3 and level 4 are available - the vehicle was never presented without bolted-on add-on armor. The Corsac has room for six dismounts and a crew of two or three. It seems likely that GDELS could offer the same enhancments as found on the Czech Pandur IIs to reach a STANAG 4569 level 4 mine protection.

One of the other two known offers supposedly made to Slovakia includes the Patria AMV, possibly in the same configuration as originally ordered with the Scipio. If these vehicles will also be made in Poland (like the Rosomak and Scipio) or be made in Sweden is currently not known. Artec is offering the Boxer MRAV to the Slovakian Army - again it is unknown which exact variant is offered.

Meanwhile Slovenia is said to intend purchasing about 50 wheeled IFVs for its military. Previously the military of Slovenia ordered a total of 135 AMV vehicles in different variants. The AMV is locally known as Svarun. The order however was halted in 2012, after issues with the funding aswell as other political issues arose, which resulted in only thirty already delivered AMVs becoming operational with the Slovenian Army. Given this fact and that the southern neighbour Croatia is already operating the AMV in larger numbers, it seems likely that the Patria AMV has an advantage over potential competitors. Potentially Artec, General Dynamics, Nexter and ST Kinetics might be interested in competing for the contract.

The Piranha 5 has already been purchased by Denmark and Spain

The Romanian Army will adopt General Dynamics' Piranha 5. In October 2017 the company announced that an initial batch of 227 vehicles will be manufactured by the Bucharest Mechanical Factory, which is owned by the Romanian state's Romarm Group. For handling the production of the Piranhas, GDELS will create a joint-venture in Romania. The military of the Eastern European country already ordered 43 older Piranha IIICs in five small batches starting in 2008.

It is not known what effect this decision will have on the development of the Agilis, a 8x8 wheeled vehicle to be locally manufactured in Romania. It is/was developed by a joint venture of the Romanian Ministry of Economy and the German company Rheinmetall. A total of 7 variants was to be made, while 80% of the work was planned to be done locally - only the engine and other drivetrain components would be imported. Hundred percent of the intellectual property of the Agilis would belong to the state of Romania, allowing easy export and local upgrades. The plans saw a total of 628 Agilis vehicles - 161 amphibious APCs, 192 heavier armored non-amphibious APCs, 24 medevac/ambulance vehicles, 90 CBRN reconnaisance vehicles, 40 mobile command posts, 75 mortar carriers and 46 recovery vehicles - to be made between 2020 and 2035, with further 4x4 and 6x6 options possible. 

The BTR-4MV1 feautres bolt-on armor modules

The state-owned Ukrainian company UkrOboronProm has presented a new version of the BTR-4 8x8 wheeled vehicle known as BTR-4MV1, which has been developed to NATO standards. This vehicle is designed and manufactured by the Kharkiv Morozov Machine Building Design Bureau and features improved armor protection over its predecessor. The BTR-4MV1 uses modular bolt-on armor that allows the vehicle to reach the STANAG 4569 level 4 and 5 (if desired) - this means the armor can provide allround protection against 14.5 mm AP ammunition and protection against 25 mm rounds along the frontal arc. The new system also allows fitting explosive reactive armor (ERA) to the vehicle in order to resist shaped charge weapons such as the HEAT warheads of rocket propelled grenades (RPGs). The modular nature of the armor elements allows replacing damaged ones, thus reducing the time and costs required to repair a damaged vehicle.

The BTR-4MV1 is armed with a 30 mm autocannon

The weight of the BTR-4MV1 is claimed to have only increased by 2 to 3 metric tons, thus the vehicle would 23-24 metric tons with some more growth potential left. In terms of mobility nothing has changed, the vehicle uses the same suspension, the same German Deutz diesel engine and an Allison transimisison just like the original BTR-4. Due to the usage of low density/high volume armor in some sections of the vehicle, the BTR-4MV1 retains the amphibious capabilties of the original design, reaching a top speed of about 10 km/h in water and 110 km/h on land.

A key difference compared to the BTR-4 can be seen at the vehicle's front. The large windscreens have been eliminated in favor of better armor protection. Commander and driver can now only see the exterior through a number of vision blocks. A number of cameras mounted along the vehicle's surface however provide the crew with a 360° situational awareness. The BTR-4MV1 retains the same weapon station as used on some of the earlier models, including a 30 x 165 mm autocannon, a dual launcher for missiles and a machine gun. There is only one set of optic on the weapon station, therefore the vehicle cannot be used for hunter-killer operations.

Challenger 2 LEP bidders downselected; tank to get new turret and new gun?

Two bidders for the life extension programme (LEP) of the British Challenger 2 main battle tank (MBT) have been shortlisted by the UK ministry of defence (MoD). The shortlisted companies will be contracted in the next few weeks for the production of two prototypes worth €25.8 million each. After a 24 month long assessment phase, the final production contract will be made with one of the downselected contenders. In case of unforseen issues, a further €7.8 million can be allocated by the British MoD. Originally the contracts were expected to be signed in October, but the project was apparently delayed, so that currently contracts are expected to be signed in December of 2016. The Challenger 2 LEP is part of the Armour (MBT) 2025 project, which is meant to ensure the Challenger 2 remaining competitive in the timeframe from 2025 to 2035.

After General Dynamics decided to join the Team Challenger 2 lead by BAE Systems, the original predictions from our overview -  suggesting that both BAE Systems and General Dynamics would be awarded separate contracts due to their ties and involvment with the British MoD and industry - were rendered obsolete. While the British MoD shortlisted Team Challenger 2, it also shortlisted the German defence company Rheinmetall. Rheinmetall has teamed up with Supacat, Thales UK and BMT; it is also cooperating with Supacat as part of the LAND 400 phase 2 proposal of the Boxer CRV for the Australian Army.

The British MoD choice effectively eliminated all other biding companies, which were the Belgian CMI Defence (in a team with Ricardo), the German company KMW (teamed up with Pearson Engineering), the Swiss company RUAG and Lockheed-Martin UK, which teamed with the Israeli company Elbit Systems for a last minute offer.

An important new detail about Rheinmetall's offer has been made public by the defence and industry news agency Jane's IHS. The upgrade concept offered by Rheinmetall includes the replacement of the old commander's sight with the Seoss stabilized electro-optical sighting system, which features a third-generation thermal imager, an eyesafe laser rangefinder and a daysight CCD camera. The Seoss is also used on the Boxer CRV and on the MBT Advanced Technology Demonstrator. The SAS 360° situational awareness system is installed on the turret roof, enabling the crew to better observe the tank's surroundings. In case of the renderings from Rheinmetall's Challenger 2 LEP proposal it includes an additional module to work as a laser warning system (LWS).

Rheinmetall's Challenger 2 LEP proposal

Not entierely sure is the status of the gunner's sight and the Pilkington Optronics TOGS-2 thermal imager. The renderings from Rheinmetall still include the armored box of the TOGS-2, which is located ontop of the gun mantlet. If the gunner's sight is replaced, why would the old box ontop of the gun mantlet be kept? On the other hand Rheinmetall's renderings show no opening at the front of the mantlet-mounted box, which makes it impossible to house any sort of optics inside of it. Also the original news article on Rheinmetall's proposal from Jane's IHS spoke of "optronics" (plural), which might imply that the TOGS-2 and gunner's sight will also be replaced. The Challenger 2 LEP proposal also includes the installation of a new fire control system with a modern electronic architecture. It seems very likely that new fully electric gun and turret drives are also part of the upgrade.

The base armor of the the Challenger 2 is not known to have received any upgrades since the tank originally entered service with the British Army in 1998. The canceled Challenger 2 Lethality Improvement Programme (CLIP) included planned upgrades to firepower, observation devices and survivability. It also included the installation and testing of the Rheinmetall L/55 smoothbore gun under the 120 mm Smoothbore Option Technical Demonstrator Programme (SO TDP). This lead to the creation of the Challenger 2 Hybrid Ordnance (CHORD), a gun combining parts of the L30A1 gun and Rheinmetall's L/55, which was meant to reduce logisitics and costs. Aside of the SO TDP, the gun and turret drives should be replaced, the optronics would have been upgraded and the survivability would be enhanced by either installing an active protection system (APS) or by upgrading the tank's armor. The CLIP however was canceled and became part of the Challenger 2 Capability Sustainment Programme (C2 CSP), which itself ended up being canceled due to a lack of funds.

The British Army even considered buying a completely new tank in response to the questionable lethality of the rifled 120 mm L30A1 tank gun against newer Russian tanks such as the T-14 Armata. The L/55 firing the German DM53 round with tungsten penetrator proved to be superior in penetrating different armor targets compared to the L27 CHARM-3 APFSDS of the Challenger 2's L30A1 gun, despite the latter featuring a depleted uranium penetrator. This is a strong advantage speaking together with the larger array of available ammunition - including the latest 120 mm DM11 programmable HE-ABM (high-explosive, air-burst mode) round - for choosing to adopt the L/55 gun without modifications or as CHORD variant.

CHORD smoothbore gun in Germany, 2005, used for static firing tests

Aside of the option to replace the L30A1 rifled gun with it's current 120 mm L/55 smoothbore gun, the German company also offers to remodel or replace the Challenger 2 turret structure. If chosen by the British MoD, this option will also include a new modular armor system, which allows easier replacement of damaged armor modules and faster upgrading of the tank's armor composition and thickness. This step might be required to mount the L/55 smoothbore gun, as the old CLIP prototype was only able to hold six rounds of the larger 120 x 570 mm unitary ammunition used by the German smoothbore gun. The British Army considered remodelling the turret interior as part of the CLIP to be too expensive.
 

Challenger 2 turret structure being manufactured at the Vickers tank plant

What type of armor would be used on the Challenger 2, if the British MoD was willing to pay for the new turret structure from Rheinmetall, is not known. A subsidiary of the German company known as Rheinmetall Chempro is however manufacturing the AMAP composite armor designed by IBD Deisenroth. The AMAP brand includes a wide variety of armor designs, some of which have been used to upgrade the Leopard 2 tanks of Indonesia, Poland and Singapore. It is also used to protect light and medium weight vehicles, such as the Iveco LMV, the Puma IFV and Boxer.

The AMAP armor is offered either as modernization for existing platfroms or as protection for new vehicle designs. It consists of a wider variety of sub-variants, making use of nano-metric steel, nano-ceramics, composite fibre materials and is used as laminated, spaced and non-energetic/explosive reactive armor (NERA or NxRA), depending on application. It seems most likely that Rheinmetall will offer an upgrade of the Challenger 2 featuring AMAP armor.

The weight of the Challenger 2 TES(H) is about 74.95 metric tons

The Challenger 2 was fitted with a comprehensive applique armor kit as urgent operational requirement (UOR) for meeting the protection levels required for the assymetrical combat in Iraq. Being adopted as part of an UOR, the new armor kit was rushed in service. It was an already existing off-the-shelf product, which was available on the market (probably even already tested by the British MoD). The Challenger 2 did not receive a new proper, purpose-made armor kit, which might have been better adopted to the Challenger 2's design, while possibly being lighter and more efficient. As a result of the theater entry standard (TES) armor kits adopted as UOR, the weight of the Challenger 2 up-armored to the latest configuration, known as TES (Herrick) or TES(H), has grown to nearly 75 metric tons - this makes the Challenger 2 probably the heaviest tank currently in service! The Challenger 2 however still features only a 1,200 hp Perkins Condor CV12 engine. 

By using AMAP armor, it might be possible to reduce the weight of the Challenger 2 MBT to less than 70 or even less than 68 tons, while retaining a similar protection level. Nano-ceramics as featured in AMAP provide a weight reduction of more than 40% compared to conventional ceramic armor. The weight savings from nano-metric steel are not as drastic, but reducing the steel mass by 17% (when using nano-metric steel in combination with composite fibre spall liners) can also be impactful. The weight of a Leopard 2 Evolution tank - i.e. a Leopard 2A4 fitted with new AMAP modules - is about 60 metric tons, or about five metric tons more than the Leopard 2A4. The Leopard 2 Evolution upgrade includes a mine-protection kit, additional side armor modules and roof armor, while also featuring the option of using the ADS system to defeat incoming tank and anti-tank ammunition.

Side armor module of the Leopard 2 Evolution defeating a PG-7VLT with tandem warhead

In case of the Leopard 2 Evolution, the side armor of the tank was capable of resisting the PG-7VLT ammunition with tandem warhead, which can penetrate more than 500 mm of steel armor after defeating explosive reactive armor (ERA). In static tests, a similar thick array of AMAP was also capable of protecting against the PG-7VR round (fitted with the same warhead as used by the RPG-29 ammunition), which is capable of penetrating up to 750 mm steel armor (600 mm after ERA). It is not known if the Challenger 2's side-armor - consisting of ERA manufactured by the Israeli company Rafael mounted ontop of a thinner layer of passive armor - is capable of protecting against ammunition with tandem shaped charge warhead arrangements. However even if it is capable of doing so, the advantage of a passive/non-explosive system is a much greater multi-hit capability, leaving less exposed area after protecting against a RPG or an ATGM.

The integration of the German MUSS softkill active protection system (APS) into British combat vehicles is being tested by QinetiQ on behalf of the British MoD.

Given that the Rheinmetall L/55 gun was already adopted in 2001 and the MUSS APS was already successfully tested on the Leopard 2A5 in 2006 - the rather late adoption of the MUSS APS in the actual army service was the result of the delays in the Puma's development, most of which resulted in changed requirements - one has again to wonder about the sense in the Challenger 2 modernization. In the end the tank is meant to remain in service until at least 2035, while the original Challenger 2 configuration was meant to stay active until 2025. The series production of the Challenger 2 LEP is expected to not start before 2020, at this time the L/55 gun will be 19 years old... and it isn't even secured, that Rheinmetall's optional offer will be purchased by the UK MoD. The Team Challenger 2 has more ties to the British industry and government, a factor which never should be overlooked.

France has already decided to upgrade the Leclerc tank. Germany is about to adopt an upgraded version of the Leopard 2A7, which as announced by Rheinmetall will be the first tank to feature the upgraded L/55A1 tank gun, which will increase the performance (range/armor penetration) by 20%. This gun is not known to be offered as part of the Challenger 2 LEP proposal, but it would be a clear and rather simple upgrade path for the future. Both  Germany and France are currently co-developing a next generation tank armed with a 130 mm smoothbore gun called the Main Ground Combat System (MGCS). According to the German defence magazine ESUT, the British MoD has not yet shown any interest in this project.

Challenger 2 upgrade proposals have been submitted

As reported by Jane's IHS, MilTechMag and DefenseNews.com, the offers for the Challenger 2 Life Extension Programme (LEP) have been submitted by the industry to the British Army. The Challenger 2 LEP aims at upgrading the Challenger 2 main battle tank (MBT) to a more modern standard, so that it is competitive in the year 2025 and beyond (currently the CR2 is expected to remain in service until at least 2035). The official name for this project is "Armour (MBT) 2025". Meanwhile Germany and France are developing a next generation tank with a 130 mm tank gun and keep upgrading their existing Leopard 2 and Leclerc MBTs.

Originally a total of seven major American and European defence companies have answered the British request for upgrade proposals for the CR2. However the US-based General Dynamics (the manufacturer of the current M1 Abrams MBT) has decided to join the Team Challenger 2 lead by BAE Systems. BAE Systems acquired Vickers Defence Systems, the manufacturer of the Challenger 2 tank. The British MoD is planning to shortlist two bidders in 2016. On request of one unnamed bidder, the deadline for submitting the proposal has been moved by one month and the program was thus delayed. With the delay, the tender response date was moved the 11th August, after this the two most promising bids will be selected in the next weeks. Two contracts of £19 million (€22 million) are expected to be signed with the favoured bidders by end of October. In total the contract for upgrading of up to 227 CR2 tanks is expected to have a worth of up to £624 million (currently €722 million).

In a different contract the UK Ministry of Defence (MoD) has decided to let QinetiQ evaluate the German MUSS softkill active protection system (APS) for integration into the Challenger 2 tank and other British fighting vehicles. A decision to adopt a softkill APS on the Challenger 2 is scheduled for April 2018.

The German company Rheinmetall has made a few aspects of their initial upgrade proposal known in a press release. The company suggest not only replacing outdated components, but also enhance the tank's capabilities further. Upgrades to mobility and protection are further options. Rheinmetall has partnered with the British companies Supacat, Thales UK and BMT.

Seoss sight of the MBT Advanced Technology Demonstrator

The press release included a rendering of an upgraded Challenger 2 tank. The commander's main sight has been replaced by the Seoss stabilized electro-optical sighting system from Rheinmetall. This stabilized optronics include a dual-axis stabilized sensor head with a third generation SAPHIR thermal imager, a laser-rangefinder and a high resolution CCD camera. It is also fitted with an integrated fire control system. The Seoss sight enables a high accuracy even when the tank is moving against static and moving targets. The same sight system has been used on the MBT Revolution/Advanced Technology Demonstrator and on the Boxer CRV. It can be fitted with the Main Sensor Slaved Armament (MSSA) remote weapon station.

It is not clear if the gunner's primary sight has also been replaced with a version of the Seoss sight or the original Gunner's Primary Sight (GPS) from Pilkington Optronics (nowadays part of Thales UK) has been kept. The rendering still shows a distinctive box ontop of the gun mantlet, which used to house the Thermal Observation and Gunnery Sight 2 (TOGS-2) on the original Challenger 2. This might imply that the TOGS-2 thermal sight was kept or upgraded, instead of being replaced by a single sight unit with integrated thermal imager. The rendering however does not show a flap in the armored box; it is not known wether this is result of the 3D model being poor or the TOGS-2 was actually replaced. 

A SAS module below a ROSY smoke grenade discharger

One single unit of Rheinmetall's Situational Awareness System (SAS) can be seen ontop of the turret. Most likely there are two or more SAS units, enough to provide a full 360° sensor coverage. Each unit contains three high definition sights (either day sight CCD cameras or uncooled thermal imagers), each set at 45° angle apart of eachother. Two SAS modules are required to provide a full 360° coverage of the surroundings either at day or night, four for a 360° sensor coverage with cameras and thermal imagers at the same time. The system is designed for easy integration in existing system thanks to an open architecture. It also features an automated warning system, which can be triggered by moving objects when enabled. Optional features of the SAS include automated mission recording, tracking and tracing, a sniper warning system (not installed in the rendering), laser warners (apparently installed) and the integration of SAS into existing fire control and battlefield management systems.  

Rheinmetall also offers the replacement of the outdated rifled Royal Ordnance L30 gun with it's current L/55 smoothbore gun with enhanced armor penetration. This gun would also enable the tank to fire programmable ammunition. 

Elbit Systems' COAPS commander's sight

Lockheed Martin UK has partnered with the Israeli company Elbit Systems for the Challenger 2 LEP. According to DefenseNews, this partnership was established just 24 hours before the deadline for the industry proposals. This is probably the result of Lockheed Martin's partner for upgrading the Warrior MICV, Thales UK, partnering with Rheinmetall. Given that Lockheed Martin's own technological portfolio, as previously noted, is the smallest of all bidding companies, they were forced to find a new partner.

Most likely the proposal from LM and Elbit will include the replacement of the sights with new models made by Elbit Systems. Most likely the commander's sight will be replaced by the Commander Open Architecture Panoramic Sight (COAPS) sight used on the Sentinel II and the TAM upgrade. This dual-axis stabilized sight includes a day sight CCD camera, a laser rangefinder and a latest generation thermal imager. The Pilkington Optronics Gunner's Primary Sight might be replaced with a similar device from Elbit Systems, possibly incorporating a thermal imager and thus allowing the removal of the gun-mounted TOGS-2 sight. Possible upgrade options include the Knight FCS (Elbit's FCS developed for the Merkava tanks) aswell as the Thermal Imaging Fire Control System (TIFCS), which Elbit developed as an upgrade option for existing vehicles.

Laser warning system from Elbit

Given that the last two international land vehicle projects from Elbit Systems included the adoption of a laser warning system, the Challenger 2 LEP proposal from Lockheed Martin UK and Elbit might aswell include the adoption of this system.

Earlier already CMI Defence announced their cooperation with the British company Ricardo UK. While CMI has experience with the manufacturing and upgrading of turret systems, Ricardo is one of the leading British companies in automotive and systems engineering. It is understood that this results in a separation of tasks: CMI Defence is responsible for upgrading the turret, while the hull is being upgraded by Ricardo UK. The latter company has been working with the Defence Science and Technology Laboratory (DSTL) of the British Ministry of Defence on optimizing the drive- and powertrain of the Challenger 2 as part of obsolecence management studies. Ricardo has developed a tool set for accessing the effectiveness and costs of upgrades.

Not much details about CMI Defence's and Ricardo's proposal are known. It might include the adoption of the RUAG-designed Compact Tank Gun (CTG), for which CMI Defence has acquired a licence; however exact details on this licence are unkown and RUAG may be the only company offering said gun for the CR2 upgrade. CMI press releases for earlier products speak of a 120 mm smoothbore Cockerill high-pressure gun; if this is the name for the licence-made CTG or refering to another product has to be clarified.

Most likely the two companies will suggest replacing the sights and electronics, while also adding a new APU or upgrading the powerpack or drivetrain of the tank. CMI Defence has used optronics from different companies for their medium and large calibre turrets, but some of their latest products utilize sights from French manufacturer Safran. However Safran is cooperating with BAE Systems.

General Dynamics and BAE Systems have formed Team Challenger 2, while RUAG announced to cooperate with a group of UK-based industrial partners. The German company Krauss-Maffei Wegmann (KMW), the Leopard 2 manufacturer, has released no details of their upgrade proposal to the public yet, but it appears likely that KMW will rely on optronics supplied by Airbus Defence and Space (formerly Cassidian), which were also used on the current iterations of the Leopard 2 MBT and the Puma infantry fighting vehicle (IFV).

Pound Sterling loosing worth, image by Stratfor

Given the BREXIT, there still should be a big question mark wether the Challenger 2 Life Extension Programme will be futile. The negative impact on the UK economy is currently undeniable, despite the actual BREXIT still being a problem for the future. The British Army is already running other expensive modernization programs such as the procurement of the Scout SV (including the turreted AJAX variant), which is heavily relying on technology and components supplied by EU-based companies, and is also looking to acquire an 8x8 wheeled mechanized infantry vehicle (MIV). Pretty much all candidates rumored for the MIV are European products, which will be more likely affected by the BREXIT than other military procurements.

QinetiQ to test MUSS APS for British Army

The British Army has contracted QinetiQ to evaluate the options for active protection systems (APS) for use on British military vehicles. In the £7.6 million ($9.89 million) contract, QinetiQ is obligated to deliver a number of MUSS based systems for evaluation. These systems will be tested against different weapon systems and will also be tested as "applique integration" on the British Challenger 2 main battle tank (MBT) from BAE Systems.

The "multifunctional self-protection system", MUSS, is a protection system developed by the Franco-German company Airbus (formerly EADS) in cooperation with the companies KMW and Buck (a subsidiary of Rheinmetall) on behalf of the German Army. The development started in 1995, but the APS was first adopted on the Puma IFV in 2015. MUSS is a soft-kill active protection system, which uses a jammer and multi-sprectral countermeasures to prevent air-launched and ground-launched guided weapons of hitting the vehicle.

Leopard 2A5 testbed with the MUSS APS

The APS has been tested on the Boxer MRAV and on the Leopard 2A5, but was only adopted on the Puma. Presentations from EADS mention a number of further vehicles onto which MUSS was proposed, mounted or tested. These include LAV, Pandur and the Leclerc, although on the latter only the warning sensors were mounted, not the active countermeasures.

Combined missile and laser warners on the German Puma IFV

For detecting missiles, MUSS utilizes optical sensors and laser-warners. Originally the PMILDS missile warner, an improved version of the EADS-developed AN/AAR-60 missile warner used on many aircrafts including the F-16 "Fighting Faclon", the UH-60 "Black Hawk" and the Eurocopter Tiger, was used in combination with separate laser warners. EADS developed a system combining both missile and laser warner into a single package. Each of these sensors can cover about 95° in azimuth and elevation. The version tested on the Leopard 2A5 tank used only two sensor units, which were covering only the frontal arc. On the Puma IFV however MUSS is equipped with four sensor units, which together provide a 360° coverage in azimuth.

For deflecting the guided missiles, MUSS uses two components: a jammer and launched countermeasures. The rotatable jammer is aligned with the path of the missile by the computer system. It creates a modulated and focused IR beam to defeat SACLOS-type missiles. In 2002 it was estimated that more than 70% of all ATGMs could be jammed via such an IR beam.

Following the detection of an ATGM, the system can automatically launch the active countermeasures. These are located in smoke grenade dischargers, which can be rotated into the direction of the missiles. Unlike conventional smoke grenades, the MUSS countermeasures create a cloud of multi-spectral smoke, that blocks IR, UV and laser beams. This is believed to be an effective way of disabling fire-and-forget missiles. On the Puma IFV, there are eight countermeasure ready to fire.

The compact version of MUSS

A stand-alone version of the MUSS APS, called "MUSS 360° Compact System" by EADS, has been developed as drop-in solution for existing vehicles. This sounds a lot like the British press release speaking of the "applique integration" of the MUSS active protection system into the Challenger 2 MBT.

Old presentations on the MUSS APS suggested the integration of radar panels and hard-kill countermeasure launchers into the system. At the time, this was the AWiSS protection system developed by Diehl Defence for the German Army. It is not known if this suggestion has ever been realized, the current version on the Puma IFV at least lacks any hard-kill components.

The contract with QinetiQ is part of the MEDUSA Technical Assessment Programme of the British Defence Science and Technology Laboratory.  This program can lead to a major boost in the protection of British vehicles and soldiers in combat, but one has to keep in mind that a research program doesn't have to lead to the adoption of such systems in the near future, specifically given the economic havoc caused by Cameron's Brexit referendum.

Chobham armor: facts and fiction 1

There are many different rumors and myths about the British Chobham armor. This is hopefully going to be a short series (at least two articles, maybe more) on Chobham armor and information takend from actual British reports on Chobham armor, which have been declassified over the past years. Chobham armor is unfortunately the target of many rumors and myths, some of which might have been made up intentionally during the Cold War to hide the armor's true nature from the Soviet spies.

In the document "Report No. P.C. 59 FEASIBLITY STUDY OF BURLINGTON FITTED TO CHIEFTAIN" from 14th May 1969 some details on Chobham armor are given. Already in 1969 the name "Chobham armor" was used to describe the new type of special armor developed in the British military facilites in Chobham, but the official codename for the armor was "Burlington".

As the name already suggests, the document is a report on possible Chieftain main battle tank (MBT) upgrade paths with Chobham armor. The addition of Chobham armor, which in different parts of the document is also referenced as "spaced armour", was to improve the protection of the Chieftain tank against hand-held anti-tank weapons, such as the common RPG-7. For a higher protection level or for greater armor coverage the weight penalty was considered to be unacceptable. 

Thus the armor was only to be applied on three parts of the tank: the hull sides, the hull front (UFP and "noseplate") and the turret. Each part was to be armored to withstand a hit from a Carl Gustav recoilless rifle (which should have a maximum perforation of about 300 to 400 milimetres into steel armor at this time).

Two different approaches were compared: protecting only the crew compartment with Chobham or protecting as much surface area with Chobham armor as possible. Both of these approaches were considered to be the hypothetical extremes (min. / max. addition of Chobham armor), with the real tank being expected to adopt a solution somewhere inbetween those extremes. The projected maximum protection level (armoring not only the crew compartment, but as much surface as possible) increased the weight of the Chieftain tank by 6.15 tons; the minimum protection level (only the crew compartment is armored with Chobham armor) weighed only 2.7 tons.

Already in 1969 the British FVRDE was working on a set of armor modules for the tank's side skirts, which was part of the maximum protection level armor set accounting to 3.8 tons of the weight. A set of skirt armor reduced to only cover the crew compartment would weigh only 2.0 tons. The number of armor modules and the exact mounting mechanism was dependent on the protection level.

Interestingly such armor was later adopted on the Challenger 1 MBT and Warrior infantry combat vehicle (IFV) for the Gulf War. The Challenger 2 MBT was fitted with similar additional protection against RPGs during Operation Iraqi Freedom.

The glacis (upper front plate) and noseplate of the Chieftain tanks was to be fitted with Chobham armor. This armor consisted of three sandwich plates in a spaced configuration with a combined weight of 0.75 tons. The addition of a burster plate increases the total weight of the additional armor to 1.05 tons. A problem of the sandwich plates is that the multi-hit capbility seems to be extremely low: As written in the document the sandwich plates (without the burster plate) "would be too disrupted by the first attacking round to be of use against a second". The burster plate would improve the armor performance by detonating the projectile before impacing the sandwich plates. However due to restrictions imposed by the fixed location of the driver's sights in the Chieftain hull, the burster plate and sandwich plates could not completely cover the hull, which is why a section of bar armor (steel bars comparable to the ones used on the Stridsvagn 103 MBT) should be fitted at the front of the hull. It seems that the British tank designer's still did not manage to design a proper hull front armor layout while retaining full visibility for the driver, which is why the Challenger 1 and Challenger 2 both have a "slot" for the driver's hatch and vision blocks in the hull armor.

When designing additional armor modules for the Chieftain's turret, the FVRDE encountered numerous problems. Due to the already large size of the turret, fitting additional armor modules to the Chieftain's turret in a fixed configuration was impossible, due to the relatively huge physical size blocking access to the engine louvres and oil filler louvres. Thus fitting the additional armor modules (or biscuits how they are called) to the turret front using hinges for mounting was considered. Here however the huge weight of each armor module - half a ton - was problematic, as this meant the crew "would almost certainly need some form of mechanical asssitance". All types of additional frontal armor to the turret would make it harder for the driver to enter and leave the tank.
Another big problem was the relatively complex shape and the layout of the turret. While the turret had a frontal surface (front elevation) of 22 square feet (2.04 m²), only 9 square feet (0.83 m²) could be covered by Chobham armor without interfering with the armament or sights. This frontal coverage with Chobham armor was deemed to be too low, so that only the sides of the turret should be fitted with it. Instead the FVRDE suggested fitting a form of bar armor (slat armor) attached to the gun barrel "at a suitable distance", however this was a purely hypothetical suggestion and no proper type of bar armor had been developed.
The turret side armor modules should be installed at maximum possible standoff without exceeding the hull width when fitted with skirts - therefore the smallest distance was estimated to still be 14 inches (355 milimetres). This was done to maximize the gain in armor protection from using Chobham; the empty space also could be used for storing some equipment. Depending on armor coverage and protection level, the weight of the turret armor was between 0.9 and 1.5 tons. In terms of construction, this armor was identical to the side skirt armor.

In 1970 the British MoD considered Burlington/Chobham armor as ready for use in a series production version of a tank. Following the rather disappointing results of investigating the feasibility to upgrade the existing Chieftain with Chobham armor, it was decided to develop a new tank based on already existing components, the so-called Chieftain Mark 5/2. Furthermore the Chieftain Mark 5/2 should take advantage of new advancements in the areas of fire control, night vision and engine power, the later was deemed to be very important due to the increased weight. The adoption of the Chieftain Mark 5/2 tank was given priority over all other British Army projects except the RAPIER missile system. Even the development of the MICV (mechanized infantry combat vehicle - fancy British word for infantry fighting vehicle) was pushed back by at least one year to allow the adoption of a Chobam-armored tank.

An interesting aspect of the a report on a briefing of the British MoD including the British minister of defence, was that the unwillingness of the American Army adopting Chobham armor being discussed. Either the failure of the MBT-70 project due to unproven technology or the focus of American military thinking on the SEA region was blamed for this. Instead of pressuring the United States to adopt Chobham armor, the British MoD rather wanted to focus on other members of NORTHAG, specifically Germany, adopting Chobham armor. This was related to the British Army of the Rhine (BAOR) being part of NORTHAG.
In order to prevent the further development of Chobham armor without British participation, the informations given to Germany were limited on a "need to know" basis, the same had been done earlier with the information released to the United States.

The development of the Chieftain Mark 5/2 was suggested, because developing an entirely new tank was not seen as possible within the near future. The FVRDE saw a given time frame for the adoption of Chobham armor, because some sort of non-British Chobham armor and countermeasures to it could be developed by any country in the future 10-20 years. Ironically, the British adopted Chobham armor with the Challenger 1, a long time after other tanks with similar special armor had entered service on both sides of the Iron Curtain.
The FVRDE suggested creating the Chieftain Mk 5/2 with an aluminium base (to keep weight at 55 tons while protection front and sides by Chobham armor), an uprated Leyland L.60 engine, modified transmission system with greater reverse speed, laser rangefinder and electronic lead calculator added to the fire control system and the introduction of the No. 21 cuploa with image intensifier sight. Problematic was rebalancing the turret and hul, so that the addition of Chobham armor did not create a front-heavy tank, aswell as achieving a satisfactory level of reliability when uprating the L.60 engine to 750 hp output. After the planned production of nine prototypes within the next 26 months, the Chieftain Mk 5/2 would have been trialed exentsively. Series production was expected to start in late 1975.

What exactly does the Chobham armor look like?

On the original feasibility study of fitting the Chieftain with Chobham armor, there are two different design types of Chobham armor used:

1. The frontal hull was fitted with a burster plate and three sandwich plates in a spaced configuration. This armor would have been used on the turret front aswell, if a better coverage was possible and other issues could have been avoided.
2. The sides of the hull and turret were fitted with box-shaped armor modules, which preferable (in case of the hull at least) had a size of 12 x 15 inches and a thickness of 8 inches. Each box holds a number of spaced, sloped steel plates with a layer of plastic bolted to the top.

For the sake of less complicated phrasing and writing, the first type of Chobham armor will be simply referenced as "Chobham type 1" and the second type accordingly as "Chobham type 2". Please note that these are in no way official designations, but merely abbrevations for this exact blog article. Also note that pretty much all thickness figures are estimated, because the documents weren't photocopied, but rather photographed fromn a slight angle. I tried my best to correct the perspective accordingly using image editing software.

The Chobham type 1 for the hull armor consisted of a burster plate, bar armor (comparable to that of the Stridsvagn 103 tank) for protecting the upper edge of the UFP (glacis), three sandwich plates and the base armor of the Chieftain tank.
The burster plate serves to fuze the warheads of HEAT and HE ammunition before impacting the sandwich plates, because the detonation would damage or destroy the sandwich plates excessively, so that they would offer little to none protection against a second impacting round. The burster plate is made of (presumably rolled) steel with unkown hardness. It's reasonable to assume that this plate - if it was rolled steel and not cast steel - has a hardness of about 300-350 BHN. It appears that the upper section of the burster plate consists of two spaced plates of approximately 20 to 30 mm thickness. Between the two plates is an airgap of about 10-20 mm, which seems to be necessary for the mounting mechanism (marked in yellow).

The sandwich plates (marked in red) have a slightly smaller thickness than the two steel plates used for the burster plate - based on the using the known glacis thickness as reference it seems possible that they have only a thickness of 15 to 25 milimetres. Each sandwich plate consist of three or five different layers. Unfortunately the resolution isn't perfect and no further details are given, but it seems reasonable to assume that they are a type of non-explosive reactive armor (NERA), consisting of an elastic material and steel. This would explain the remarks about the multi-hit capability being limited unless fitted with a burster plate. Possible configurations could include:

• steel (~5-10 mm) - an elastic plastic or rubber (thinner thickness, maybe 3-5 mm) - steel (~5-10 mm) 
• plastic (~2-5 mm) - steel (5-10 mm) - elastic plastic (~2-5 mm) - steel (~5-10 mm) - plastic (~2-5 mm)
• or thin steel with thicker plastic layers, i.e. steel (~2-5 mm) - plastic (5-10 mm) - steel (~2-5 mm) - plastic (~5-10 mm) - steel (~2-5 mm)

The glacis plate of the Chieftain is known to have a thickness of approximately 85 mm; depending on measure point on a real Chieftain tank it was 82 to 86 mm thick. It is made of cast steel, which has a hardness of 260-270 BHN - comparable to Soviet cast armor, but worse than any type of armor grade rolled armor steel.

The armor modules used for the Chobham type 2 follow a different construction pattern. The values are again estimated/measured from the photograph, which unfortunately suffers from some perspective distortion. Given that the scaled measured values all happened to be very close to fractions of an inch (and the thickness was said to be 8 inches), I decided to utilize inches as measurement unit this time.

The special armor array is housed in a steel container, which has a thickness of ⅛ inch (0.125 inch = 3.175 mm). On the exterior surface an ¼ inch (0.25 inch =  6.35 mm) thick layer of plastic (marked red) is located, a layer of the same thickness is mounted in the inside at the backplate.
Inside the steel box an array of plastic - steel sandwiches is located. All these plates are sloped at 30° from the horizontal and consist of an ¼ inch thick plastic plate on an ⅛ inch thick steel plate. The plastic and steel are hold together by bolts (marked in yellow). Unless hitting the direct top or bototm section of the armor module, a projectile has to penetrate three of the plastic-onto-steel sandwich plates.
An interesting aspect of this armor are the brackets/spacers (marked in blue) between the sandwich plates. These brackets might be designed to hold the plates together in a flexible configuration. I.e. they are under some amount of tension, but when being hit by a force (such as a penetrating shaped charge jet), the bracket (and the sandwich plate) bend towards the next lower plate. This would explain the plastic layer ontop of the steel plate, which might have some amount of elastic/reflective properties. The plastic layer also could serve to prevent the steel plates getting jammed together at the penetrated/damaged sections (which would result in a much lower protection for future hits). Once the tension of the brackets - and the possible additional force applied by the plastic - get to strong, the upper plate moves back into it's original position. The movement of the sandwich plates  will not only mean additional material being moved into the path of the penetrator, but also have a disruptive effect on the fragile shaped charge jet. But this is only speculation, as the available documents do not describe the true nature of Chobham's working mechanism. 

For the Chieftain Mk. 5/2 the available drawings from declassified British documents include a bit less information on the armor layout - the armor is only shown as black plates without showing the actual layers forming the plates. However it is known that the turret armor for the Chieftain Mk. 5/2 would utilize seven Chobham plates additional to the base armor (which is aluminium). Interestingly for the top and the bottom section of the new turret armor layout, there is always one thicker plate and six "normal" plates. It is unkown if the thicker plate is meant to show the burster plate or is a different type of sandwich plate.
However the available documents give another interesting bit of information on Chobham armor: the equivalent weight of steel armor used on different sections of the tank. The frontal armor consisted of 50 mm aluminium at 60° and Chobham armor weight-equivalent to 134 mm steel at 60° from the vertical. This means the frontal armor weighed as much as 302 milimetres of steel armor.
The side armor consisted of 50 mm aluminium at 0° and Chobham armor weight-equivalent to 36 mm steel. Together this weighs as much as about 53 mm steel armor. The usage of aluminium and Chobham allowed the Chieftain Mk. 5/2 to nearly keep the Chieftain's original weight, while being considerable better protected.

How effective is Chobham armor?

In case of the Chieftain upgrade with Chobham armor, the design goal was full or limited protection against the shaped charge warhead of the Carl Gustav recoilless rifle. Additional protection against KE attacks was not required. The skirt and turret sides were expected to be "immune" against the Carl Gustav HEAT ammunition even when impacting at normal, whereas the protection against 120 mm APDS ammunition to angles of 60° fired from a distance of 1,300 metres. In case of the maximum armor configuration with additional hull armor, the glacis was "immune" even to missiles with shaped charges with a 6.0 inch cone diameter and a 45° cone angle. Protection against 120 mm APDS over the 60° frontal arc was also granted - but this is hardly a suprise given the relatively low penetration (150 mm steel at 60° from the vertical at 1,000 metres) and the relatively thick base armor.
Against a 5 inch shaped charge with 60° cone angle the skirt armor did not provide enough protection at normal - an overmatch of 4.5 inch in penetration capability was given. At an impact angle of 45° or greater however the armor provided full protection. A 6 inch and a 7 inch shaped charge warhead had no troubles penetrating the side armor, unless the angle was greater than 65° - then the 6 inch warhead with 45° cone angle failed to penetrate. In case of the turret side armor (same construction as skirt armor), it was possible to increase the amount of protection against the 6 inch warhead with 45° cone angle by spacing the armor modules from the main turret armor. This reduced the maximum impact angle with penetration from 65° to 55°.

In case of the Chieftain Mk 5/2 with Chobham armor and an aluminium base, the frontal armor was designed to resist all KE threats at point blank except the Soviet 115 mm APFSDS - this could penetrated the front at 200 metres according to British estimates. It was also regarded as "immune" to 6 inch diameter HEAT warheads (60° cone angle), 5 inch HEAT warheads and the Carl Gustav ammo. The side armor could be penetrated by 85 to 115 mm KE ammunition at any particaluar range at impact angles larger than 45°. The side armor could stop 76 mm AP-T at 2,000 metres and 50° angle, 57 mm AP-T at 2,800 m and 50° angle and 45 mm AP-T at 1,000 m and 40° angle. At point blank it managed to resist impacts from 23 mm AP-T and HMG ammunition.
It also provided full protection  against Carl Gustav ammunition, 6 inch and 5 inch shaped charge warheads at angles greater than 65° and 60° respecitvely. This protection assessment is based on British calculations made with penetration figures for Soviet weapons provided by the US Army. However it has been assumed that the spaced armor configuration of Chobham armor might actually result in a greater level of protection than calculated.
Together with the empty space between the side armor and skirt armor (where the tracks are located), the Chobham armor version for the Chieftain Mk 5/2 seems to offer an considerable increase in armor protection per weight. Depending on the exact penetration, the armor array provides 5.35 to 7.14 times as much protection as a single plate of steel armor of the same weight (for an estimated penetration of 300 to 400 mm steel armor). However it has to be noted, that the empty space between the tracks considerably increases protection against smaller HEAT warheads - according to a document from Dr. Manfred Held, the ~10 mm thick steel/rubber skirt of a Leopard 2 tank can stop (together with the 40 mm base armor) a RPG-7 with 300 mm penetration when hit at an angle of 60°. This would mean that the empty space together with the disrupting effect of a spaced armor configuration on the shaped charge provides protection comparable to about 200-210 mm steel in this specific case. The spaced configuration of the Chobham armor modules of the Chieftain Mk 5/2's skirts could hence only offer about 3 to 5 times as much protection as (simple) spaced steel armor of the same weight. This exact layout/location however still seems to be a "best case" scenario for Chobham armor, as it uses a weight-efficient aluminium hull construction, lots of empty space and does not have any noteworthy amount of armor designed to protect against kinetic energy threats.

According to a letter written to Lieutnant-General A. Schnez, the head of German Army, from the 10th of March 1970, Chobham armor was offering additional protection compared to steel armor against shaped charge attacks only:

For some years our Fighting Vehicle Research and Development Establishment has been working on different types of armour designed to defeat Hollow Charge attack. The point has now been reached where the establishment has developed a form of armour that can be incorporated in tank and other armoured vehicle designes which will resist Hollow Charge attack, while giving the same degree of protection against Kinetic Energy attack as conventional armour.

Later versions of Chobham armor are understood to have improved protection performance against kinetic energy attacks such as APDS and APFSDS ammunition though. In the PROGRESS REPORT ON BURLINGTON  from February 1970 it is mentioned that the Burlington array No. 4 (unfortunately no details on this exact array are available yet) has been improved by 15 to 20% in protection against hollow charges and "probably against APDS, HESH etc.". This could be achieved without increasing the size, but increasing the weight by less than 10%. The original armor performance could be achieved by scaling the array down, i.e. reach the same protection level as originally, but with 10% less weight and about 20% less thickness.
Back then the British research of improved versions of Chobham armor was focused on further improving the performance against HEAT ammunition mainly. By adding aluminium as a structural component of "all future Arrays of Burlington" the spalling caused by overmatching penetrators could be reduced from 45° to 10°. In terms of protection against kinetic energy, all that is mentioned is "[a]ll modifications to Burlington must always retain or enhance its KE effectivness".

Is the name "Chobham" correct?

The easiest answer would be "yes and no". The official codename for the initial versions of Chobham, including the ones presented to West-Germany and the United States was Burlington armour. The name Chobham armour was however already used inofficially in documents from 1969, before the British ministry of defence first revealed the existence of Chobham armor to the press. The idea that the name "Chobham armor" was created by journalists not knowing a better word for the highly secretive armor that had been presented to them, can thus be dismissed as a myth.
Between 1970 and 1975 a new type of armor (or a modified version of Burlington) was developed under the Project Almagest. Unfortunately no details can be given here, because I do not have access to the UK National Archives from here and a trip to England just for one blog entry doesn't seem to be reasonable for a hobbyist blog like this.
Later the United Kingdom developed a new type of armor - probably just a modified version of Burlington - known as Buckhorse armor. This was developed together with West-Germany for the Future Main Battle Tank (FMBT; Kampfpanzer 3 in German), a joint-venture tank to replace the Leopard 1 and Chieftain MBT. To what extend the armor was ever developed is unfortunately unkown at this point of time due to lacking information.

The Challenger 2 uses Dorchester armour, an improved version of Burlington armor. This has also been (inofficially?) been labeled as "Chobham Mk. 2".

An interesting side note is the Pageant armour, which was a identical to Burlington armor and intended for export to Persia (to be used on the FV4030/3 "Shir Iran 2" tank). The name "Pageant armour" was chosen to hide the true nature of the armor - being the highly classified Burlington armor to be used on NATO tanks - from the British NATO allies West-Germany and the United States. The existence of Pageant armor should refute the myth that Chobham armor is "super classified" and only made in Britain and handled by British troops, a rather odd myth popular in some British Army fanboy groups.

So where is the ceramic armor?

There is no ceramic material used in any early version of Chobham. The drawings from the studies for fitting the Chieftain with Chobham armor and the development of the Chieftain Mk. 5/2 both showed spaced armor configurations of what seems to be non-explosive reactive armor (NERA). In the document ASSESSMENT OF FOREIGN ARMOUR DEVELOPMENTS from the 9th April 1970 it is written:

The basic principles of orthodox armour developemtns ion the WEST are well known and have been studied by all countries which produce armoured fighting vehicles. These developments have included the study of materials such as improved steels, other metals, plastics, ceramics, glass and other fibre re-inforcment to produce homogenous, composite and sandwich armours. None of these armours provide defence against HEAT attack on principles similar to BURLINTON.

Thus it's rather easy to see that the early versions of Chobham armour - the versions demonstrated to West-Germany in 1970 and to the United States to some (presuambly minor) extend in 1964 to 1968.
But what is with the more advanced versions of Chobham? Do they consist of ceramic tiles in a honeycomb structure with some special, magical binding mechanism?

The best answer to give to this question seems to be "no, not really". While some versions of Chobham armor might use ceramic materials to some extend (i.e. the spaced Chobham array in combination with a ceramic armor array), it can be seen that even "modern" Chobham armor from the late-1980s utilizes spaced sandwich plates.

Damaged Chobham armor on a Warrior IFV

Based on photographs from damaged Warrior infantry fighting vehicles (IFVs), which had been fitted with Chobham armor, one can clearly see that the Chobham armor is a form of spaced armor. Otherwise the RPGs would not be able to punch deep holes into the armor modules and in some cases (as pictured above) even get stuck inside the armor, when the warhead doesn't fuze properly.
Furthermore a photograph from a damaged M1A1HA main battle tank, which should utilize a version of Chobham armor with additional layers of depleted uranium, reveals that even the "heavy tank version" of Chobham seems to incorporate layers of spaced sandwich plates.

International versions of Chobham - armor of similar construction to Chobham

While Chobham armor was/is big advancement in armor technology, it has not been a unique type of armor solely used on British tanks or tanks made by countriess to which the British government allowed the export of sensitive military technologies.
Despite there being cooperation in terms of armor and tank technology between West-Germany and the United Kingdom, the actual Leopard 2 is claimed to be somewhat indigenous. The relationship between the Leopard 2's armor and Chobham armor might be investigated in a future article. However one explanation to this might be Dr. Manfred Held, the man who invented the modern explosive reactive armor (ERA) design in 1967/68 (patent awarded in 1969). By replacing the explosive layers in ERA with rubber or other elastic materials, NERA can be created. This armor concept was patented by Dr. Held in the early 1970s in Germany.
According to Soviet/Russian sources, the German Army tested a type of NERA consisting of 6 sandwich plates consiting of steel/rubber/steel sandwiches with different thickness against shaped charge warheads and found the results to be satisfactory. Such armor seems to be similar to the "Chobham type 1" refernce mentioned earlier in this article.

T-72B turret with special armor exposed

The Soviet Union developed a similar type of sandwich armor in the 1980s, which was first employed on the T-72B turret in 1985 and later also in the hull armor array in 1988/89. This armor consists of multiple sandwich plates consisting of a steel plate with a thickness of 21 mm, a 6 mm rubber layer and a thin 3 mm steel plate. The sandwich plates are spaced by 22 mm thanks to the use of steel spacers. When hit frontally, a penetrator has to travel through 4 to 5 of the sandwich plates in order to reach the crew compartment. Interestingly, this armor has been described at least once as "Soviet Chobham" from a Western author.
This armor was copied in a rather crude form by the Iraqi military engineers/tank designers for the local upgrade of the T-55, which has been designated "T-55 Enigma" by NATO sources. This armor was probably based on the T-72M1M (initial export version of the T-72B), of which a few ended in the hands of the Iraqi despite the international embargo.

Details of the Merkava turret armor

The modern versions of the Israeli Merkava tank - i.e. the Merkava 4 and upgraded older models - seem to utilize a type of sandwich armor comparable to the Chobham type 1 reference mentioned above. Details from undamaged and damaged tanks show that the turret armor employ an array consisting of several spaced sandwich plates. Older versions of the Merkava such as the Merkava 2 and Merkava 3 seem to employ a different type of armor.

So it seems that the underlying concept of the Chobham armor has been researched and implemented by various nations other than Britain - however this took quite a while, given that the British research on Chobham armor started in the mid-1960s.