SP42 Cobra

The SP42 Main Battle Tank (formally Special Purpose-42 Main Battle Tank), commonly known as the Cobra, is an anti-matériel/anti-fortification vehicle used by the UNSC Defense Force. It is manufactured by Misriah Armory.

Service history
The SP42 Cobra was first deployed in 2497 during Operation: CHARLEMAGNE, after a team of ORION Project commandos had covertly struck a blow against the Secessionist Union in the previous year. Following this initial deployment, the SP42 MBT was presumably used throughout the Insurrection. The Cobra was then used extensively during the Human-Covenant War, particularly during its earlier stages, in which SP42s were frequently used in both offensive and defensive roles.

Chassis
Despite the Cobra's classification as a main battle tank, it is designed to be lightly armored, fast, and maneuverable. Unlike most tanks, the SP42 uses six all-terrain wheels that enable impressive mobility even over rough terrain and are protected by pivoting front and rear wheel guards. The two rear wheels are retracted when the vehicle enters lockdown. Like the M9 Main Anti-Aircraft Tank, the Cobra's designation as a main battle tank is likely due to its general architecture and framework than because of its function.

Armament
Unlike most UNSCDF vehicles, the Cobra fills two distinct roles: that of a mobile anti-matériel platform and that of a self-propelled artillery piece. The SP42 Cobra is equipped with a pair of M66 light railguns on its turret that fire high-density ferrous slugs - which are twice the size of those used by the M68 Gauss cannon - designed to penetrate enemy armor using sheer kinetic energy. These railguns fire intermittently, not in a single burst, as the energy required to accelerate the slugs to the speeds required to pierce the heaviest armor can only be managed for one of the cannons at a time. Synchronized fire from both railguns can destroy even the most heavily armored tank, with penetration that easily outguns the M808 Main Battle Tank's standard M512 90mm cannon.

In addition to the Cobra's anti-vehicle role, the vehicle can be stabilized upon the ground, "locking down", and deploy an arcing-trajectory M98 105mm light railgun which fires a conventional explosive shells at supersonic velocities. The explosive and kinetic forces of the shell complement each other to increase the damage inflicted. An M98's shell, when specially outfitted, can penetrate a Type-30 Locust's energy shield and destroy the platform, while one shot can disable the shield upgraded Type-26 Wraith's shield and deal minor damage.

Upgrades

 * Deflection Plating: gives the Cobra extra protection. Cost 400 resources.


 * Piercing Shot: enables railgun to penetrate multiple targets, damaging each. Cost 900 resources.

Trivia

 * Like most UNSC vehicles, the Cobra is superficially similar to its animal namesake. When locked down, the SP42 MBT lowers itself and becomes poised to fire; this is similar to actual cobras, which typically coil before striking. The SP42 is especially similar to the spitting cobra, which can project venom to great distances.
 * The Cobra's artillery mode has an uncanny resemblance to the Terran siege tank from Starcraft, which can transform from tank mode to siege mode, with a sacrifice of mobility for longer range and greater firepower.
 * The vehicle was originally described as being similar to a Russian 'Katyusha' rocket artillery vehicle, which was spurred on by the appearance of vehicles similar to the M9 Wolverine but possessing a different ordnance rack. This was a case of mistaken identity, as the vehicle sighted was actually a Wolverine, but with an upgrade adding a second missile pod, creating confusion.
 * Despite its designation as a main battle tank, the Cobra is technically a hybrid self-propelled gun and tank destroyer. The "tank" moniker is likely an in-universe misnomer or simplification, as with the M9 Wolverine.

List of appearances

 * Halo Wars