YrC9 Arkantyr 155mm Self-Propelled Howitzer, 1st Noble Guards Cavalry Regiment the Imperial Life Guard, on training exercises in Barony Myrstirei
YrC9 Field Deployment Model
Designation:
Numerical Designation: YrC9
Name: "Arkantyr"
Key Data:
Crew: 3 (Commander, Gunner, Driver)
Cost: 17.8 million NSD
Dimensions:
Length: 8.1m (Hull)/
Height: 3.0m (Turret Roof)
Width: 3.8m (4.2m w/ Modular Side Armour)
Weight: 74t
Performance:
Maximum Speed: 72kph road speed (governed).
Cross country speed: 52kph
Acceleration: 0 to 32kph in 4.8 seconds
Operational Range: 400km
Armament:
155mm SC22.9 56 calibre solid propellant howitzer (64 rounds, 48 ready)
Commander's weapon: 12.7mm MG/H8A3, interchangeable with other armaments.
Additional: 12x mounted multipurpose grenade launchers, modular systems allow for further options.
Protection:
Passive: Calumnis-3L (metal-composite matrix outer layer, NERA, composite tiles, IRHA plates/hull, fibreglass/rubber/Spectra spall liner)
Active: Orenthel Active Protection System
Crew Protection: NBC protection (main + auxiliary), pentafluoroethane crew compartment fire extinguishing, Halon 1301 + foam fuel tank extinguishing and self-sealing suite.
Electronics:
Ganymede FCS
SAIC Combat Networking
Power:
Propulsion: 2,200hp (steady state) opposing piston hyperbar.
Transmission: Automatic (8 forward, 3 reverse).
Suspension: Hydractive
Power/Weight: 29.73hp/tonne
Overview
The transfer from the Leclerc 140 to the HT9A7 was, without doubt, one of the most significant changes to come across the Crown Army since the Military Reforms of 1994. Taking a tank fleet numbering in the tens of thousands, the ultimate objective of the Armed Forces Staff was to fully replace existing frontline tanks within three years through intensive production and acquisition, citing the importance of adopting modern armoured vehicles into the Anemonian arsenal as soon as possible in the face of the proliferation of high quality tanks across the world that easily outclassed the Leclerc in Anemonian service.
The YrC9 Self Propelled Howitzer is a weapon developed through the momentum of the HT9A7 project. With the expansion of the original development brief into the full vehicle replacement project that Project Fiensietyr had become, the creation of a new frontline fire support weapon became a priority for the Anemonian Armed Forces, looking to replace the outdated M109A6 'Paladin' howitzers in the service of the Crown Army. The objective was ambitious; the rise in combat effectiveness desired by the Army was a large one, and necessitated the exploration of hitherto unused technologies. It was clear enough that the creation of a howitzer system similar to current use ones like the PzH 2000 was no longer acceptable; rather, the Army desired a competitive weapons system that would operate at the very forefront of extant artillery technology, providing the highly mechanised Army with the punch it required on the battlefield, in every environment the YrC9 might be called upon to operate in.
'Arkantyr', the resultant vehicle, surpassed all expectations. Drawing the vast majority of its automotive design from the HT9A7, the YrC9 combines incredible mobility with a design built around its highly effective 155mm howitzer, creating a uniquely effective howitzer built for endurance and effectiveness in combat. Accuracy, power and flexibility are all core concepts explored and implemented in this next generation fire support vehicle, drawing upon a multitude of innovative design concepts to provide the Crown Army with a weapon that would be able to meet the high expectations set by the introduction of the HT9A7, taking a step ahead of its potential opponents through a uniquely Anemonian marriage of technological prowess and battlefield practicality.
Developed over a three year period on the HT9A7's vehicular base, the initial production variant of the YrC9 was supplied to frontline forces in the Federal Empire of Asakura in early 2010. In service there, it acquitted itself remarkably well, making full use of its reaching distance and power to provide support in a variety of forms in a wide range of combat situations to troops across the nation. Tried and tested on the field of battle, the YrC9 currently serves as the main line howitzer for the Crown Army in support of a wide variety of combat operations across the globe.
Armament
The main armament of the YrC9 SPH is the 155mm SC22.9 56 calibre solid propellant howitzer. Designed to replace the previous generation of short barreled howitzers employed by the Crown Army in the M109A6 Paladin, the SC22.9 is a rifled gun-howitzer that utilises a combination of technological advancement and design effectiveness to extend reaching distance, accuracy and effectiveness against a variety of different potential foes, with the ability to engage a number of targets quickly and accurately.
Carrying 64 rounds, the ammunition capacity of the YrC9 is comparatively high as far as most self-propelled howitzers are concerned, due to the ability of the vehicle to make full use of its larger free space and forward mounted engine to dedicate a large portion of the vehicle's rear area to ammunition storage. However, unlike most armoured howitzers, the YrC9 differentiates between 'ready' and 'stored' ammunition; this is due to the unique ammunition storage layout, which emphasizes ease of reloading and access over sheer ammunition capacity. Two 6x4 racks at the back of the turret store a total of forty eight rounds of 155mm ammunition. These forty-eight rounds can quickly and easily be reloaded by opening the two turret rear doors, exposing the racks, allowing resupply vehicles with the appropriate equipment to easily access and reload the YrC9's ready ammunition supply. Furthermore, the stored ammunition is located in two racks at the centre of the hull's rear, simplifying access to the secondary supply via the rear hull door.
Though many current systems employed by a number of other nations utilise larger bore cannons to increase range, the presence of multiple launch rocket systems for extended range engagements within the Crown Army meant that the use of such cannons was, in consideration of the decrease in firing rate, ammunition capacity and mobility, unacceptable, given the overall decrease in the weapon's ability to provide effective support in exchange for longer firing ranges. Rather than attempting to become a jack of all trades, the YrC9's basic design opts to stay out of the operational remit of other pieces of equipment and maximise effectiveness in its own.
The SC22.8 is a 155mm gun howitzer of 56 calibres (8680mm). The barrel is constructed of autofrettaged steel, increasing its resistance to the high firing pressures of the 155mm round, and is rifled to increase the accuracy of the shells fired by the gun, which, unlike the APFSDS rounds employed by the HT9A7's 128mm gun, are not fin stabilised, necessitating the employment of spin stabilisation. It is attached to the breech block by an uninterrupted thread for quick removal (with electronic sealing for the midwall's cooling fluid comparment. Due to the rifling, the use of ceramic lining as on the 128mm SC10.8 is impossible, due to the difficulty of appropriately applying the composite overwrap; however, the inability of chrome lining to effectively prevent barrel erosion in the face of higher effectiveness propellants means that a replacement is nonetheless necessary. The SC22.8 employs a tantalum-titanium alloy lining (10% titanium content) in place of the usual chrome lining found on many guns; the use of an alloy in place of pure tantalum creates a lining that is both far more effective than simple chroming and devoid of the softness problems that are inherent in the latter. As such, though not exhibiting the erosion resistance of the SC10.8, the SC22.8 nonetheless manages to achieve as high a level of resistance possible given the rifling necessary for accurate fire. The weapon's thermal jacket is constructed of 35% glass reinforced polymers, with an automatic compressed air fume extraction system at the rear end of the gun barrel of prevent oxygen depletion and other potential effects on the crew. Additionally, in order to maximise the effective firing rate, accuracy and barrel life of the SC22.8, the weapon's design has been taken one step further through the active cooling of the barrel. This is achieved via a midwall heat transfer fluid chamber containing an isopropyl glycol heat transfer medium (used instead of ethylene glycol due to the toxicity of the latter), which transfers the heat generated by the barrel to heat exchangers located in the turret, and temperature sensors for thermal management. By quickly dispersing heat and keeping the barrel cooled, the SC22.8 is able to achieve rates of fire unrivalled by other systems in use by most armed forces today, allowing it to make full use of the advantages inherent in the 155mm round's potential firing rate.
A travelling lock is placed on the glacis plate to secure the gun while in movement, and folds back when not in use.
Recoil mitigation is achieved through two primary methods; directive and absorptive. The slot type muzzle brake attached to the forward end of the gun barrel redirects propellant gases to partially counteract the recoil forces generated by the weapon's firing. The hydro-pneumatic recoil mechanism utilised on artillery systems since the late 1800s is, of course, employed in the YrC9 to allow for the safe firing of the weapon, while four hydraulic retarders, two to either side, located around the weapon further inhibit recoil by absorbing rearward forces to minimise its effective on vehicle stability. These recoil control mechanisms restrict the effect recoil forces have on both vehicle stability and armament alignment upon firing, increasing accuracy, consistency of accuracy and, ultimately, the firing rate of the YrC9. Gun stabilisation is achieved via to independent electro-hydraulic systems with independent horizontal and vertical stabilisation (full dual-axis electro-hydraulic stabilisation), and gyrostabilisation to provide the SC22.8 with an exceptionally recoil resistance and stable firing base from which to project aimed fire.
The 155mm round used by the SC22.8 is large, and thus necessitates the use of two-piece ammunition. The need to load both ammunition and charges, together with the high firing rate and flexibility demanded from a howitzer system, poses a unique challenge when attempting to design a fully automated loading system. However, the speed and crewing advantages of an effectively design autoloading system mean that development in this area was ultimately necessary to establish a clear margin of superiority over the M109A6 in service with the Crown Army. The autoloading system employed by the YrC9 operates broadly along similar lines to that employed in the HT9A7, allowing for a great degree of loading flexibility. Rounds are stored in a pair of 6x4 racks at the back of the turret, providing the YrC9 with 48 ready rounds with a further 16 rounds stored in the hull, which can be put into the loading racks by crew if necessary. The weapon utilises a modular charge system that eliminates the need to store multiple types of charges in the hull; rather than the four employed in the M109A6, the modular charge system employed by the SC22.8 utilises two types of stackable charges that cover all those ranges covered by the four used in Anemonian service and more. Though the utilisation of a single modular charge would arguably have been preferable, experiments with such charges found that the utilisation of the charge in short range zones exhibited problems including the failure of the projectile to exit the gun tube, residue combusting upon opening the breech and, in higher zones, the reflection of pressure waves between the breech and the projectile base. As a result, two distinctive charges were produced to rectify this problem; the first, utilised in short range zones, employs a single base charge propellant with no additives, while the second, utilised in long range zones, employs a triple base charge propellant with additives to reducing coppering, muzzle flash and barrel wear. By stacking these two types of charges (combinations of the two types are not used), the YrC9 is able to extend and modify its reach within and beyond that of many existing howitzers, reaching ranges of about 34km with standard shells, 40 with base bleed shells and beyond with rocket assisted ordnance. The autoloading system relies upon streamlined operation to maximise loading speed, and utilises a dual mechanism to load shells and charges at high speed. Shell loading is greatly simplified due to the presence of the two ammunition racks at the back of the turret; the mechanism simply selects one of these and loads it. Meanwhile, the second autoloader mechanism selects the appropriate types and quantities of charge modules from 'stacks' in the hull, and raises these to the breech to load these. This dual selection mechanism allows the two piece ammunition system to be prepared for loading simultaneously, greatly increasing the loading and thus firing speed of the gun. The control system is highly similar to that used in the HT9A7, insofar as the gunner is provided with a wide degree of flexibility in choosing ammunition. It utilises a combination of virtual-memory stored location records and bar code reading to correctly select and prepare both rounds and charges. Unlike many autoloaders, the system is also capable of shifting across a variety of operation modes. 'Single type automatic' causes the autoloader to consistently select a single type of round and load it upon extracting the spend casing of a firing round without additional confirmation. On the other hand, the gunner can also utilise a manual confirmation system where a desired round is selected prior to loading, providing the operator with flexibility in terms of ammunition choice. Finally, the gunner can also set up a 'firing list', selecting a number of rounds in firing order for the autoloader to automatically select and load one by one upon firing. The highly streamlined autoloading system and fire control system allow for rapid loading and firing to the tune of capabilities such as eight round simultanous impact, or eleven round per minute burst fire and five per minute round sustained fire; in exchange for a lower ready ammunition capacity via turret racks, the YrC9 creates a direct-feed autoloader that both decreases the movement time between rack to breech and the gap between shell and charge loading and marries it with a gun that is designed to suppress the usual inhibiting effects of rapid firing.
In the event of autoloader failure, two additional crewmen can operate the loader manually, one to load ammunition and the other to load charges.
The ammunition family employed in the YrC9 is labelled the M12, and comprises a comprehensive selection of ammunition designed to provide the YrC9 with reach and flexibility befitting a gun system like the SC22.8. This wide range of ammunition is optimised for a number of roles, and interchangeable battlefield use allow the howitzer to perform a number of tasks effectively and efficiently in service.
M12/E is a label for the overall family of high explosive rounds employed by the YrC9. A 155mm round intended for conventional support missions, the round is a pure high explosive munitions employing directional fragmentation and blast effects to maximise damage against personnel, materiel and lightly protected vehicles. The explosive charge, where most armed forces utilise TNT, has been replaced by a Dinitroanisole/Nitrotriazolone based munition for safer handling due to the relative insensitivity of the latter in comparison to TNT, despite retaining the explosive force of older charges. The label 'family' is used due to the existence of a number of different rounds in this category; the development of a number of technologies resulting in the creation of six distinct munitions, with two out of these used in common field service by the Crown Army. The standard High Explosive round notwithstanding, the family also includes a version utilising base bleed to increase the range of the shell. The vacuum behind the shell create due to its blunt base is a major source of drag, and to rectify this, base bleed technology extends a small ring of metal marginally past the base of the shell and utilises a gas generator to increase pressure in the area behind the shell, helping to rectify this problem to some extent. However, this results in a marginal loss of accuracy due to additional turbulence and a slight loss of explosive capacity due to the need to create space for the gas generator; as such, the increase in range is accompanied by a partial dip in impact effectiveness. Furthermore, a rocket assisted projectile has also been developed; as the name suggests, the projectile employs solid propellant rocket assistance to increase range at the cost of accuracy to ranges far beyond the ranges accessible by conventional and base bleed rounds. This allows 155mm systems like the YrC9 to reach out to extended ranges without suffering the disadvantages inherent in larger gun systems. Thirdly, the M12/E family also includes GPS guidance capabilities. GPS programming into the fuze utilises folding fin guidance and braking together with a satellite link to guide the shell as close as possible to a set GPS coordinate, creating a guided shell capable of achieving high levels of accuracy. The six variants of the M12/E are as follows: M12/E (standard HE), M12/E-L (base bleed HE), M12/E-R (rocket assisted HE), M12/EG (GPS guided standard HE), M12/EG-L (GPS guided base bleed HE) and M12/E-Aug (GPS guided base bleed rocket assisted HE). M12/E-Aug, or 'Augmentise' for 'Improved', is a system that employs both base bleed and rocket assistance to take the range of the round from the conventional M12/E's 34km maximum range to something around 50km. Though the increased turbulence created by both base bleed and rocket assistance would normally result in significantly lower accuracy, the round uses GPS guidance and a non-rocket assisted terminal stage guidance period to largely compensate for this. In standard use, the YrC9 employs the standard M12/E and the M12/E-Aug to provide the gunner with the best of both worlds; however, stockpiles are kept of all six rounds (albeit uneven stockpiles), meaning that any of the rounds above can, in theory, be used by the YrC9's crew. In standard use, the M12/E is the round most likely to be kept in hull storage, as extended bombardments using the round extensively enough to require additional stocks are generally in situations where the crew can afford to transfer rounds from storage into the autoloader.
M12/AD is a family of mine-based area denial rounds used by the YrC9 to further extend the operational flexibility of the howitzer. Two types of munitions are used; AD-P (Area Denial-Personnel) and AD-A (Area Denial-Armour), and they are used in conjunction to maximise their effectiveness when deployed on the battlefield. The base concept in itself is simple in construction and operation. A shell containing nine mines of either type is fired, and uses an expulsion charge at the top of the shell to scatter the mines across the area of impact, with partial rubber coating on individual mines protecting them from hard impact while refraining from inhibiting effectiveness. Two self-destruction time frames (5 and 48 hours) are used to ensure that the M12/AD does not cause long term damage, making it a uniquely long-term friendly mine system, while natural colouring of both individual mines and deployed trip-wires means that the mines are able to remain relatively discreet when in use. M12/AD-P is a mine with an HF1 steel metal casing to maximise fragmentation, with an RDX based explosive charge to cause both blast and fragmentation casualties. It deploys ten weighted and coloured trip-wires around the mine upon impact, and detonate the mine when pressure is applied to the wire. M12/AD-A uses a main charge composed of RDX, and an electromagnetic fuze to ensure that activation solely occurs upon detection of a vehicular target as opposed to accidental activation by an infantryman. The munition explodes upwards, and creates a self-forging fragment penetrator to aim for and generally achieve crew kills. M12/AD-A is not a game-changer per se; as a single mine within a 155mm gun system's round, it has limitations, and as such cannot be expected to fully disable a top-tier main battle tank. However, against anything below this, it can be reliably expected to achieve kills, and will certainly cause damage to even the best protected vehicles.
M12/Mu is a GPS guided munition that employs folding fin GPS guidance to achieve high levels of accuracy and minimise collateral damage. The shell contains 50 high explosive fragmentation anti-personnel submunitions and an explosive charge at the back of the round to disperse these munitions. Unlike conventional cluster munitions, these submunitions are not delayed effect; rather, they are simply used to increase the round's area of effect against infantry targets, and is used as a wider range, lower damage alternative to high explosive shells, designed to maximise personnel damage while restricting it in all other areas. GPS guidance is used to direct the round to its target, with a very low circular error probable. Upon reaching a given distance from it, the weapon ejects its head, which contains the GPS guidance fuze, and the dispersal charge ignites to directionally expel these submunitions. With a wide effective area of effect, M12/Mu is a round that gives the YrC9 the ablity to effectively engage and destroy infantry targets with a high degree of accuracy and very restricted collateral damage. These cluster submunitions are self-destructing (with a two minute time-fuze).
M12/Yr is a dedicated anti-tank munition. The shell itself has a base bleed 155mm body, and is capable of carrying the ordnance out to nearly 38km. It contains two sensor-fuzed submunitions containing an explosively formed penetrator warhead. Upon launch, the round travels along a normal arc. A timed fuze, set prior to firing, detonates an explosive lining that splits the shell in two, pushing the nose assembly away; the submunitions then begin to fall. Deploying winglets for both stability and guidance, they then independently begin to search for targets within a 200m radius through both milimetre wave radar and infra-red scans to detect a vehicle. Upon detecting one, the submunition guides itself into a position where it can then detonate its warhead; the subsequently created explosively formed projectile strikes the top armour of the target vehicle, likely from out of the effective range of a modern hard-kill active protection system, to penetrate the turret, hull and damage the vehicle or crew. The extensive range of this munition provides the YrC9 with the ability to lay down devastating anti-vehicle suppot at long ranges and high speed, providing yet another advantage to its users.
In addition to this wide variety of specialised munitions, the YrC9 is also equipped with a significantly wider variety of shells for use as necessary. The M12/C smoke generation shell employs the Composition A smoke also employed in the HT9A7's 80mm grenade dispersal launchers; the explosive dispersal of chlorosulfuric acid interspersed with fine metal coated carbon fibres to generate an aerosol smoke cloud creates an obscurant that is both far safer than the alternative (Composition B, a White Phosphorous based obscurant used by the HT9A7) and nonetheless highly effective for providing cover in both the visible and millimetre-wave spectrums. Furthermore, a range of 155mm direct fire APFSDS and HEDP rounds, as well as a GLATGM, have been produced for use in the YrC9 (M12/S, M12/EY, M12/mod M, respectively), made possible by its thicker-than-normal armour array, but these are not used often due to the YrC9's position as, first and foremost, a fire support asset.
Next to the left turret hatch, the YrC9 also sports a pintle mounted MG/H8A3 12.7mm Heavy Machine Gun for use against infantry, vehicles and aircraft. The MG/H8A3 is a short-recoil operated rotating bolt machine-gun utilising forced air cooling and forward porting to evacuate heat and propellant gases. With a barrel constructed of cold hammer forged steel, the external receiver of the weapon itself is, as a relatively new weapon, constructed of 30% glass reinforced polymer (making it relatively lightweight while remaining resistant to temperature buildups and sudden shocks), and the need for a replaceable barrel is largely removed through the installation of the highly efficient air cooling system. The ammunition is fed via a disintegrating link (a scaled up version of that utilised in the MG3/MG3R1 series’ 7.7mm ammunition), and the cyclic rate of fire of the weapon is mechanically alterable via the trigger block like the MG3 series, alternating between 450 and 750 rounds per minute as desired. The weapon itself is normally operated via a trigger located on the weapon’s single-handle (as opposed to the spade trigger used by some), but one of the differences between the infantry deployed and most vehicle deployed versions of the MG/H8A3 is the fact that they are, in fact, initial electrically ignited weapons (i.e. the initial trigger pull is replaced by electric ignition) to make them compatible with the HT9A7’s co-axial block system and greatly mechanically simplify the Remote Weapon Systems in service with the Anemonian Armed Forces. In general, two types of rounds are used with the MG/H8A3 as a component of the YrC9; ball ammunition, for use against ‘soft’ targets, while HEIAP is employed for use against harder targets.
Armour
The YrC9, as an armoured self propelled howitzer, is a weapon that requires some degree of protection. Though its envisaged role was as a rear area support vehicle, two facts were recognised; firstly, as artillery was a preferential target in an age of ever extending munitions ranges, protection against usual threats (such as GLATGMs and frontal assaults) was desirable. Secondly, the need to consider potential breakthroughs was also taken into account; as such, the YrC9 uses heavier armour than the average self-propelled howitzer. The frontal arc is highly protected, and top armour is maintained at levels similar to that of the HT9A7. This modified armour suite has been labelled 'Calumnis-3L' to note its position as a modified and lightened form of the armour suite employed in the HT9A7.
Outer layer protection is achieved through the use of a Titanium Diboride (TiB2) based metal composite matrix with a fibreglass spall backing. This metal composite matrix, by being significantly harder than materials used in most ammunition-based applications, is capable of breaking up rounds, including penetrators, and, through the toughness of the metal composite matrix, results in the controlled distribution of kinetic energy absorbed from the round. As the controlled distribution results in the creation of a damage area only marginally larger than the size of the round from which energy has been transferred, with any spall effects absorbed by the fibreglass backing, the external protection is capable of sustaining multiple hits from anything up to the 12.7-14.5mm round range commonly utilised in modern heavy machine-guns. The resultant outer layer of armour protection is significantly lighter than the equivalent volume of RHA, and nonetheless capable of entirely stopping armour piercing small arms fire while significantly wearing down the effectiveness of high performance kinetic penetrators before they reach the armour blocks themselves.
Another component of the YrC9’s passive protection suite is non-energetic reactive armour (NERA). In modern times, the continued utilisation of explosive reactive armour (ERA), widely used as most armoured vehicles’ first-line protection against shaped charge warheads, has been proven to be impractical and ineffective due to a number of reasons. Firstly, the explosive composition of the filler utilised in ERA results in a situation where hits against the vehicle can potentially result in collateral damage, especially in confined spaces. Due to the necessity of utilising infantry support for armoured vehicles in such environments, this means that the practicality of ERA equipped tanks is greatly decreased due to their subsequent inability to operate effectively in certain combat situations. Secondly, however, the modern development of tandem shaped charge warheads and their frequent employment in anti-tank guided missiles, where a smaller charge detonates ERA prior to the detonation of the main charge, has created a situation where the combat threats faced by the Anemonian Armed Forces are more than capable of easily defeating ERA based solutions with minimal effort through the use of a simple design aspect in their anti-tank warheads. As such, the utilisation of NERA was looked into by FOAM during the design process for the HT9A7, and eventually replaced all planned employment of ERA in the tank due to its clear advantages over its predecessor. The NERA utilised within the YrC9 is formed out of panels consisting of a 10mm thick layer of rubber lining sandwiched between two 6mm thick plates of steel (Domex Protect 500). When a projectile hits the NERA panel, resultant outward motion by the two Domex plates increases the effective thickness of the armour in that area, providing increased protection against projectiles. Furthermore, however, the lack of an explosive element means that the NERA utilised within the YrC9 is both capable of taking multiple hits (to some extent) and causes no resultant collateral damage, as well as being far more resistant to the effects of a tandem charge warhead; both in terms of protection and resultant damage, it is a more desirable form of protection. Cross-wise orientation of NERA panel is employed in the armour layout to ensure that the jet bulge in the first panel generated upon impact does not result in material erosion in the second, increasing the overall protectiveness of the NERA layers against shaped charge warheads in exchange for a minimal increase in volume. Overall, the result of this is that the NERA protection of the YrC9 is both superior to that of standard ERA and parallel arrangements of NERA, giving it first-line protection against almost any shaped charge warheads thrown at it.
In terms of ceramics, the YrC9 primarily employs nano-ceramic Titanium Diboride (TiB2). Titanium Diboride is, in terms of properties, highly similar to the titanium carbide currently frequently used in many armoured vehicles armour and armament suites; however, in many respects, it can be said to be superior. At room temperature, its hardness is almost three times that of the equivalent volume of fully hardened structural steel. Its melting point is also incredibly high, at 3225˚C, and the result is that armour blocks incorporating normal Titanium Diboride tend to be both incredibly impact resistant and capable of withstanding the high heat generation of chemical energy warheads. Chemically, it is also a relatively field-friendly material, insofar as it is more stable than tungsten carbide when in contact with iron, and less prone to oxidation at anything short of extremely high temperatures. As such, Titanium Diboride is a highly effective material when used in impact-resistant armour applications, capable of withstanding the effects of both HEAT rounds when used in conjunction with other forms of armour but, more importantly, very effective through high levels of hardness against kinetic energy rounds and penetrators. In addition, not content with stopping there, designers decided to take the high-performance characteristics of Titanium Diboride one step further through the use of modern technological developments in nanotechnology. By starting with high purity powders and running them through plasma melting and hot isostatic pressing to inhibit grain growth, the time-temperature window of densification was extended. With nanograin sizes maintained throughout, the result was the significant decline of porosity in ceramics passed through the treatment procedure, and the subsequent production of full density ceramics at the nanometer scale. Higher strength and hardness was achieved, as such, due to the resultant low-angle, high-strength grain boundaries and less dislocation within the overall structure due to the finger grain size. The resultant nano-ceramic Titanium Diboride improves upon an already superior material to create a uniquely effective and efficient ceramic for use within the YrC9's composites.
The two metal alloys utilised in the YrC9 are Type 7720 Titanium-Aluminium alloy and IRHA (HRc 40, HRc 48). Type 7720 Titanium-Aluminium alloy draws from the natural advantages of a titanium-based alloy (high stress resistance and toughness for its weight range, as well as corrosion and temperature resistance). In this particular case, however, the primary advantage of Type 7720 stems from its weight advantage; compared to RHA, Type 7720 is capable of providing properties close to those of ceramic materials at 38% the weight of the equivalent volume of RHA. Of course, the difficulty of machining Type 7720 makes it an impractical choice for usage across the entirety of a vehicle, and the result has been that the titanium alloy has not been used as the hull material for the YrC9 out of purely practical concerns about the workability of the material.
IRHA, or Improved Rolled Homogeneous Armour, is a metal alloy that modifies the basic chemical composition of standard RHA to create a far harder material, altering one of the base components of many modern armoured vehicles to create a more effective alternative suited to the battlefields of the 21st century. The basic chemical composition of IRHA (by weight percentage) is 93.68% iron, 0.26% carbon, 3.25% nickel, 1.45% chromium, 0.55% molybdenum, 0.4% manganese, 0.4% silicon and some impurities (<0.01% phosphorous, <0.005% sulphur). With a 1% increase in the nickel composition of the alloy and a smaller increase in a number of other elements (chromium, molybdenum and manganese), the resultant material is much harder than standard RHA whilst retaining similar levels of ductility and toughness. Weldability and machinability, of particular importance for IRHA’s hull applications, is similarly preserved at RHA levels by maintaining carbon content at ~0.26% or below. IRHA’s physical properties are further determined by the heat level at which it is tempered; HRc 40 grade IRHA, which is used for hull applications, is tempered at 529˚C, which HRc 48 grade IRHA, for applique armour, is tempered at 218˚C. The differentiation in role stems from the fact that HRc 48 grade IRHA is more effective against kinetic energy penetrators at the cost of far less resistance to fragmented munitions that HRc 40, making it more usable in applique armour (where its shortcomings are compensated for by other materials). IRHA, as such, provides the YrC9 with all the advantages of rolled homogeneous armour but, again, goes one step further by modifying the basic chemical composition of this erstwhile material to give the YrC9 another advantage over many contemporary armoured vehicles.
In terms of layout, the armour is separated into two parts; the armour itself, and the hull construction and interior. The armour consists of an outer layer of TiB2 based metal composite matrix over a cross-wise oriented NERA layer, another layer of the metal composite matrix, then panels of Type 7720 TiAl alloy sandwiching square tiles of HRc 48 IRHA and nano-ceramic TiB2. Beneath this is a plate backing of HRc 48 IRHA. NERA layers and some armoured protection can also be found on the roof of the SPH for protection against HEAT-based ATGMs. The hull itself is constructed of HRc 40 IRHA. The crew compartment’s interior is equipped with a spall liner made of 20% glass composition fibreglass backed by Spectra and rubber; the energy is expended against the fibreglass, with any further spalling being absorbed by the backing to provide the crew with highly effective protection against internal damage.
Active Protection System
To provide active protection to the YrC9, engineers at foam endeavoured to create a lightened and simplified version of the Solothel Networked Vehicle Protection System for use by the howitzer, which would be operating in lower intensity combat situations. Labelled Orenthel, this active protection system incorporates a portion of Solothel's soft-kill systems, while refraining from using systems perceived to be unnecessary in a detached combat environment, necessary only for the eventuality of entering combat.
The detection system utilised by Orenthel is two-tiered, and aims to achieve the highest possible detection speed with a minimal number of false detects by utilising a range of data from different sources to create an accurate picture of the vehicle's combat environment, and thus maximise the effectiveness of its threat detection and thus prevention and interception. The first tier of the vehicle’s sensor system is a set of laser warning sensors installed around the vehicle. Within each sensor unit, both coarse and fine resolution detection systems are employed to provide a wide degree of coverage to the YrC9. With overlapping sensor coverage, the system detects lasing and is able to provide the crew not only with warnings, but informs them of the specific sector in which lasing has been detected, providing the crew with directional threat awareness that then allows for accurate reaction by both the crew and the automated threat response systems. The second tier of the detection system is a millimetre-wavelength radar based on flat panel additions around the vehicle and a single fixed unit to provide the YrC9 with 360˚ degrees radar protection, allowing the YrC9 to not only acquire incoming targets, but their speed, relative distance and profile to create an accurate picture of the projectile. The effectiveness of the system is, again, greatly increased by overlapping search sectors; together with the high performance processors utilised by Orenthel, this allows the overall target acquisition array to utilise its wide selection of sensors to achieve extremely high reaction speeds, greatly increasing the speed and thus effectiveness and success rate of its target interception. The two tiers of the system guarantee the accurate and effective threat detection of a number of different threats at a number of different ranges, and it is this effectiveness that gives Orenthel the ability to surpass and exceed most current active protection systems.
Smoke generation is usually achieved by a number of 80mm grenade units, generally varying from between twelve to twenty-four launchers with a total of anything between twenty-four to forty-eight canisters installed on the vehicle itself, and can be set to be launched via manual ignition or automatic ignition upon sensor reception. The exact parameters can be set in detail; as the different sensor equipment used by Orenthel, and to some extent profile comparison, allow it to identify reception information and categorise it, automatic smoke ignition can be set to occur within limited parameters, such as lasing.
The 80mm grenade launchers themselves are not restricted to a single type of ammunition. In some cases, they can be equipped with 80mm anti-personnel grenades; these utilise hexogen tolite as an explosive base for the directional shattering of a steel casing, resulting in a high-explosive/metal fragmentation based anti-infantry defence mechanism with the directional deployment of the device optimised by direct control by Orenthel itself, which is capable of utilising returns from its IR sensors if necessary to identify and eliminate hostile infantry forces (though this option can be turned off when operating in conjunction with allied infantry).
In terms of smoke, the YrC9 is provided with two separate types of smoke for operation in close proximity to unarmoured elements, and operation in open areas against hostile forces. This differentiation is necessary due to the nature of the smoke composition used in each grenade. The ‘A’ model, designed with operation in close proximity to non-protected elements in mind, utilises the explosive dispersal of chlorosulfuric acid to spread out an aerosol smoke cloud and reduce the acid concentration of the hydrochloric and sulphuric acid produced as a result of the reaction. To compensate for the resultant reduced effectiveness of the smoke cloud, the smoke composition also contains fine metal coated carbon fibres to act as obscurants in the millimetre wave region, thus allowing Composition A to provide the YrC9 with adequate protection in a variety of ranges. Composition B differs slightly from Composition A in that, while retaining the explosive dispersal mechanism and the carbon fibre content to act as a radar obscurant, the actual chemical composition of the smoke grenade has been changed to a white phosphorous-based composition. This is due to the pyrophoric qualities of WP; because it burns when put into contact with the air, it creates a short period of IR inhibition through a highly volatile exothermal reaction. Furthermore, the chemical content of Composition B grenades is increased in comparison to A, with the explosive dispersal lessened, due to the fact that it is designed solely for effectiveness and disregards general welfare due to its envisaged area of use; as such, Composition B grenades offer a much higher performance alternative to the YrC9 when engaging hostile forces in the open field, a quick acting smoke grenade that, through the use of white phosphorous and metal coated carbon fibres and their explosive dispersal, create a quick blanket of thick smoke effective as an obscurant in the visible, infra-red and millimetre-wave spectrums to provide the YrC9 with full spectrum defence. Of course, both Composition A and B are potentially harmful to those caught within the device’s area of effect upon ignition (without protective equipment in the case of A, and in either case with B), and as such, automatic deployment by Orenthel is an easily alterable option; Orenthel’s control mechanism, displaying flexibility as always, allows the crew to select the parameters within which the smoke canisters are to be deployed, ranging from full automation upon threat detection to complete manual control. As such, the 80mm grenade-based defensive suit utilised by the YrC9 provides the tank’s crew with a highly effective set of soft-kill defence mechanisms capable of block the target locks of weapons operators and in-flight munitions, but also allows them to minimise collateral damage via a selection of ammunition and the flexibility of the control system.