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A Hydra Flak Tank during combat

The Hydra Flak Tank, also known simply as the Hydra, is the main mobile anti-air artillery piece of the Astra Militarum. It is produced on hundreds of Forge Worlds across the Imperium and is widely-used in nearly every regiment. The Hydra, like many other Imperial military vehicles, is based on the Chimera armoured personnel carrier chassis, and is armed with a set of twin-linked Hydra Autocannons. Hydra Autocannons are a set of long-barrelled Autocannons mounted on a turret with highly sophisticated tracking and targeting equipment.

The Hydra is used to defend important ground units such as Imperial Guard artillery batteries and armoured columns from enemy air attacks. Non-mobile units or structures are usually defended by a Hydra Platform, a stationary version of the Hydra Autocannon, while the Hydra itself is generally deployed with mobile units. The Hydra's powerful guns are capable of quickly reducing enemy aircraft to smoking debris, but they can also be levelled towards the ground to engage enemy infantry and lightly armoured vehicles when circumstances warrant. The Hydra's Autocannons are so effective in the destruction of enemy infantry that Imperial commanders often overlook this breach in regulations and some regiments will use their Hydras as front-line vehicles when the threat of air attack is reduced or no longer present. Hydra tanks are usually kept in their own company within a regiment, but are rarely deployed together in company formation and are instead assigned to other companies which require air defence.

Whether faced by lightning-fast xenos fighters or daemonic, leather-winged monstrosities, the Hydra Flak Tank is ideally equipped to blow aerial foes out of the sky. The Hydra's predictive logic-spirit singles out and locks onto its targets with the tenacity of a predatory beast. Autoloaders engage with a rising whine as the Hydra's turret traverses, its quad Autocannon howling as it fills the air with sawing lines of firepower. Few airborne enemies, no matter how debased or unnatural, can survive for long once they are locked in the Hydra's sights.

Hydra Quad Autocannons keep the skies clear, allowing a Tech-priest Enginseer to shepherd other armoured units to battle.

Though the Hydra has sufficient armour to weather a fair degree of punishment, it is intended primarily as a support vehicle rather than a main line battle tank. Nonetheless, the Hydra is far from defenceless. Its hull can be fitted with various armaments, and its Autocannon can be angled downward to slaughter grounded enemies when necessary. However, the Hydra's Machine Spirit hungers only for airborne prey, its tracking servos refusing to trace the lumbering paths made by foes that cannot fly, meaning it must be aimed manually and, therefore, less accurately when targeting opponents on the ground. Company Commanders must therefore ensure they have seconded enough infantry or tanks to guard their Hydra batteries from direct attack. With a sufficient escort the Hydras can remain safe from harm while concentrating their efforts on keeping the skies clear.

For most Imperial Guardsmen, be they artillery crew, tankers or foot-slogging infantry, the screaming approach of enemy aircraft is a sound that evokes absolute dread. When the black shadow of monstrous wings falls across them, the men of the Guard have little defence besides prayer. So it is that the Hydra has acquired a reputation as an omen of good luck. With nicknames ranging from "steel saviours" to the more colloquial "bug-zapper," Hydras are viewed with comradely affection by most soldiers in the Astra Militarum. A common tradition amongst the men of many regiments is to rap their knuckles against the hull of a Hydra before battle; this so-called "angel's knock" is performed in solemn silence and intended to draw the vigilance of the Hydra's Machine Spirit in the battle to come. Hydra crews share in their vehicles' popularity, enjoying something approaching folk-hero status amongst their comrades and a place around any squad's camp fire. Some Hydra crewmen revel in the regard of their comrades and the adrenaline rush of their duty, while others find the weight of responsibility uncomfortable, but few are foolish enough to believe the camaraderie of their fellows is untainted by self-interest.


The commander of a Hydra scans the skies for threats

The Hydra is armed with a turret-mounted set of twin-linked Hydra Autocannons, long-barrelled Autocannons that unleash explosive flak rounds at an extremely high rate of fire. The Hydra's gunner and loader are positioned in the vehicle's turret and work together to keep the weapon's automated loading mechanism and complex targeting systems operational. The vehicle is also armed with a single hull-mounted Heavy Bolter, which can be used against enemy infantry that get too close or can be swapped out for a Heavy Flamer for the same purpose. The tank can also be equipped with Camouflage Netting, Extra Armour Plating, a Hunter-Killer Missile Launcher, a mine sweeper, improved communications equipment, a Pintle-mounted Heavy Stubber or Storm Bolter, rough terrain modifications, a Searchlight, track guards, and Smoke Launchers.

Even a single Hydra can throw up a storm of flak, swatting enemy aircraft from the skies with an adamantine fist. When several of these vehicles draw up and open fire, the devastation wrought on airborne foes is spectacular. Monstrous xenos wings are reduced to streamers of flesh, the gibbous flight-sacks of daemonic drones burst under the weight of puncturing fire, and even heavily armoured Attack Craft are reduced to perforated scrap as their fuel tanks and internal magazines explode.


The following is the list of all known Hydra variants:

A Wyvern armed with its signature Stormshard Mortars

  • Wyvern Suppression Tank - The Wyvern is a short-ranged self-propelled artillery piece of the Astra Militarum. The Wyvern is a variant of the Hydra, exchanging the Hydra's anti-air Hydra Autocannons for a pair of twin-linked Stormshard Mortars. The Wyvern was designed for the claustrophobic environment of urban warfare, its weapon system capable of raining down curtains of shrapnel upon enemy infantry without ever exposing itself to danger. The Wyvern uses a bastardised version of the Hydra's advanced auto-targeting system that constantly runs proximity sweeps of the area for concentrations of enemy infantry. The Machine Spirits of these vehicles are renowned for their malicious nature, as they actively seek the most tightly-packed or vulnerable grouping of infantry and strain to target them, sometimes even overriding the commands of their crews. When the Wyvern does fire its Stormshard Mortars, they emit a distinctive roar as they spew clouds of shells high into the air.

Known Users of the Hydra

  • 28th Valhallan Armoured Regiment - The 28th Valhallan Armoured Regiment was stationed on the planet Betalis IV and made use of the Hydra against Eldar air support.
  • 6th Cadian Armoured Regiment - The 6th Cadian Armoured Regiment made extensive usage of the Hydra during the defence of the planet Betalis III against the Eldar of Craftworld Mymeara.
  • 74th Cadian Armoured Regiment
  • 142nd Cadian Armoured Regiment
  • 1652nd Cadian Armoured Regiment - Regardless of their crews' attitudes or affectations, when Hydras roll into battle they can make all the difference to an Astra Militarum army. On Sarentos III, during the Battle of the Sandsea, the Cadian 1652nd Armoured were tasked with breaking the Necron line. Roaring across the dunes, the Leman Russ Tank squadrons of the 1652nd directed a withering rain of fire into their deathless foes. Great geysers of crimson sand were blown high into the air as the Necron line disintegrated before the tankers' armoured charge. Then came the Doom Scythes. Screaming over the battlefield on howling repulsor-jets, several wings of the ominous alien aircraft began to strafe the Imperial tanks with the glowing beams of their death rays. Flames billowed and black smoke gouted forth as first one Leman Russ and then another exploded. Though well prepared and outfitted for ground warfare, the Cadians were fighting without the military support of the aerial formations of the Aeronautica Imperialis, meaning they had no aircraft of their own to intercept this threat in the sky. For a perilous moment it appeared as though the 1652nd would be hurled back in disarray -- but their commander had issued his own call for reinforcements. Barrelling over the crest of a nearby dune came three Hydras, tracks churning spumes of sand in their wake. The flak tanks marked their speeding targets and opened fire, filling the sky with fury. One after another, the Necron Attack Craft were riddled with holes. Driven by eldritch technology, the living metal of the ancient xenos flyers began to writhe, moving to fill in the gaping rents. Yet no matter how fast the puncture wounds were resealed, the Hydras' quad Autocannons continued to savage their targets. Flurries of sparks and crackling green lightning wreathed the hulls of the Doom Scythes as they plummeted to the dunes below, tumbling end over end and exploding with enormous force. As the last of the enemy aircraft turned tail and fled, the surviving tanks of the 1652nd pushed forward again, their route to victory now covered by the watchful guns of the Hydras.
  • 2nd Brimlock Regiment, "The Sky Wardens" - The 2nd Brimlock Regiment depended upon the Hydra during the defence of Bastion 312 against rebel drop forces, and acquired a confirmed kill ratio of 99,999 to 1.
  • 8th Valhallan Armoured Regiment - The 8th Valhallan Armoured Regiment made use of the Hydra during the Sallan's World Offensive.
  • 87th Armageddon Steel Legion Regiment
  • 46th Palladius Armoured Regiment
  • 2nd Phyressian Armoured Regiment
  • 8th Pardus Armoured Regiment

Adeptus Mechanicus Technical Specifications

Hydra Flak Tank
Vehicle Name: Hydra Main Armament: Turret-mounted  twin-linked Hydra Autocannons
Forge World of Origin: All Known Forge Worlds Secondary Armament: Hull-mounted Heavy Bolter or Heavy Flamer
Known Patterns: I - XIX Traverse: 360 degrees
Crew: 1 Commander, 1 Driver, 1 Gunner, 1 Loader, 1 Comm-Operator Elevation: 0 to 79 degrees
Powerplant: Vulcanor 16 Twin-Coupled Multi-Burn Main Ammunition: 600 Rounds
Weight: 38 Tonnes Secondary Ammunition: 300 Rounds
Length: 5.29 metres Armour:
Width: 3.78 metres
Height: 5.10 metres Superstructure: 100 millimetres
Ground Clearance: 0.45 metres Hull: 150 millimetres
Max Speed On-Road: 50 kilometres per hour Gun Mantlet: N/A
Max Speed Off-Road: 35 kilometres per hour Vehicle Designation: 0427-941-3030-HY44
Transport Capacity: N/A Firing Ports: N/A
Access Points: N/A Turret: N/A

See Also


  • Codex: Astra Militarum (8th Edition), pp. 47, 111
  • Codex: Astra Militarum (6th Edition) (Digital Edition), "Hydras," "Heavy Support - Hydra Battery"
  • Codex: Imperial Guard (5th Edition), pg. 51
  • Imperial Armour, pp. 43-44, 56-59
  • Imperial Armour Volume One - Imperial Guard and Imperial Navy, pp. 171-176
  • Imperial Armour Volume One - Imperial Guard (Second Edition), pp. 9, 175-179, 262-263, 267
  • Imperial Armour Volume Eleven - The Doom of Mymeara, pg. 27
  • Imperial Armour Volume Twelve - The Fall of Orpheus, pg. 189
  • Aeronautica Imperialis (6th Edition), pg. 24
  • Honour Guard (Novel) by Dan Abnett