XV8-10 Upsurge Battlesuit

The XV8-10 Upsurge Battlesuit, ( Tau Lexicon: Her'ex'vre Or'es'vral) is a largely discontinued model of Tau battlesuit that was engineered by the Gai'kal Sept in 739.M41 during a period that would become known to the inhabitants of the world as the Va Lyo'au, or Great Isolation.

Finding its roots in several blueprints of thickly designed, bulky pre-XV8 battlesuit designs that existed before conventional high-mobility technology in battlesuit armour technology and mechanical limb and sensory development was made available to the public. With in-field tests showing the XV8's to operate brilliantly in conjunction with Mont'ka tactics of high-mobility and maximum firepower in contrast to its limited success in static trap-orientated Kauyon tactics, plans were funded by Earth caste administrators to see fourth the development of battlesuits that sacrificed mobility and flexibility in favour of armour, sensory capability, payload and energy efficiency. Years of tactical and structural analysis both simulated and in-field gradually phased out the need for the battlesuit to require a fully-swivelling head and functional hands, with head sinking into the reinforced frame of the battlesuit to become immobile and hands disappearing from usage altogether. In final versions, the back and shoulders of the battlesuit evolved to become comparatively hunched to support larger supplies of ammunition within the abdomen of the suit, with finished designs resembling the designs of the XV25 Stealthuit and the later XV107 R'varna.

Twin-linked weapons became standard issue for the XV8-10 Upsurge battlesuit, mirroring the XV9 Hazard close support suit that would not see development within the greater Tau Empire until the Third Sphere expansion. The suit was further fixed with ground-to-suit sensory nodes across its entire surface, with particular emphasis on the rear of the vehicle's structure, programmed to map the suit's position against the ground to gain more detailed bearings on its surroundings and furthermore providing the pilot with a simulated 360˚ view of his or her surroundings on top of the approximate 180˚ view provided by the head-mounted multi-spectrum camera relay. Initial prototypes quickly denied usage of a full deployment of cameras across the entire suit to reduce engineering and supply costs.

The nano-crystalline alloy which provided the basis structure for the armour of all battlesuits later saw heavily-funded development in the fields of Earth Caste nanotechnology and chemistry. The lattice structure of the alloy was reconfigured through synthesis attempts into a near purely face-centred cubic structure similar to that of diamond. Whilst tests showed positive results, production costs for fully-restructured armour plating were predicted to be unsustainable en masse due to the sept's isolation. Regardless of this, on commission of an Ethereal youth of the Hwa'ran dynasty around 52 production models of the XV8-10 Upsurge Battlesuit and a further 400 XV8 Crisis Battlesuits selected for testing did demonstrate some capacity for sustainable usage of thin (<10mm) surface level re-plating with of the restructured material. These commissioned suits proved fairly effective in resisting larger payloads of standard Imperial-grade ranged fire, yet procured only a 16% success ratio in resisting lascannon and melta fire. Projected results estimated an increase to an approximate >46% success ratio for fully-restructured armour, however these tests appeared noticeably extrapolated from optimistically skewed figures.

To pan out and optimise what limited resources were available, since testing, the four hundred upgraded crisis suits were since phased into standard service within the Gai'kal fire caste. Whilst knowledge of the upgrades were kept strictly away from public eyes, information still managed to be leaked on the back of a soon widespread rumour, giving birth to a cult of superstition amongst Shas'ui to bet upon their assigned battlesuit's slim - but still nevertheless existing - potential to be fielding the restructured armour plating. The culprit for the leakage was never identified.

Since reunification with the Tau Empire, the Upsurge battlesuit has generally been phased out of widespread usage within the sept, with the make officially being classed in imperial designations classifications as the XV8-10 Upsurge Battlesuit upon seeing contact with Imperial forces for the first time. The make still sees active service in siege warfare and pure-minded usage of Kauyon defensive warfare by Gai'kal commanders.