Document: Transcribed excerpt from the publicly-available audio guide (First released 171 ASC) to the Restabilizing War Museum in Republic City. This paleodisc is the third of five, entitled The Hall of Machines. For full document, see [DOCUMENT REFERENCE EXPUNGED]
[Engine noise. Sound of projector fire. Ambient war noise.]
It was technology that drove the Ember Group, and Technology which won the Res War. Here in the Hall of Machines, you'll see real Ember Group vehicles from the conflict, from the smallest SP Harness to the mighty bulk of the Industrious Dragon. All of these vehicles are still fully functional, and are activated once a year as part of Breakthrough Day memorial celebrations. Please, do not touch or climb on the vehicles unless permitted to by museum personnel.
[Six minutes omitted. History of Ember Group vehicular technology, including references to the Forges. Early tank prototypes dating from the Schism, small experimental submarines, the airship Sozin's Ghost.]
Item Five: The Roaring Dragon
[Actor's recording]
Men were dying around me. My friends. My comrades. The line was breaking. And then... and then the cavalry arrived. I'll never forget that day. They say the Roarers are a symbol of the Ember Group's efforts in the Res War. I disagree. The Roaring Dragon was the Ember Group.
-Suo He, Corporal, Second Standard Infantry
The most widely-produced vehicle of the Res War, the Roaring Dragon Mark 1 had already been in service for ten years before hostilities commenced. During the conflict, this sturdy, easy-to-produce and versatile design proved itself countless times. It is a testament to the legacy of this design that most vehicles in this hall are in some way based off its chassis. Armed with a Seafoam Mark IX-T steam projector, and a turret-mounted autobow, the mobile, versatile 'Roarer' could provide firepower in a wide variety of battlefield environments. With up to 65 millimeters of bolted armour, it was reasonably survivable in most conflicts, and its high top speed made it a slippery target. It was crewed by four men- a commander/signalman, a driver, a gunner, and a projector loader/engineer. This design showed its age during the Breakthrough, where its bolted armour and 270-degree turret rotation proved to be major handicaps against other armour. Notice how the hull is welded and curved while the turret is the distinctive bolted octagonal shape- the Roaring Dragon was originally to be outfitted with a conical turret, typical of modern vehicles, but a simpler, more economical design was eventually used to save construction and repair costs.
[One minute omitted. Brief overview of the Roaring Dragon Mk1b, and the Roaring Dragon Mk 2 after the war.]
Item Six: Howling Dragon
[Actor's Recording]
At night, the Dragons howl and fire rains from the sky. Where did they come from?
-Written in the remains of a diary, recovered from a Norther position after heavy shelling
The anvil to the Roaring Dragon's hammer, the Howling Dragon and its derivatives were the primary artillery vehicle used by the Ember Group for most of the Res War. The peculiar twin-hulled design was the result of a design mistake- the first prototype submitted for consideration was built with twice the boiler space necessary. The resulting vehicle was capable of putting on so much pressure that a second projector was added to the rear hull to literally let off steam. Most vehicles, like this one, which served in the Arctic theatre, were equipped with two 90-millimeter ten-kilo projectors, although a small number of vehicles with significantly heavier weapons were built. Howling Dragons were so named for the poor sound insulation in their hulls- they were infamously loud weapons. The Howling Dragon chassis was seldom used in other vehicles, mainly due to the extreme weight of the heavy coil springs needed to absorb the recoil of the twin weapons.
Item Seven: Emperor Dragon
[Actor's Recording]
Reinforcements not necessary. Have Emperors. Charging.
-Last optigraph transmission of Colonel Tsenachaq, Twelfth Superheavy Tank Brigade, before the defeat of Tulpa Swarm 5.2 at the Second Battle of Glacier Bay.
Eleven meters long. Four high. Four wide. One hundred and fifty millimeters of frontal armour. Four main weapon mounts spread across two turrets. The Emperor Dragon and its derivatives have been in service with the Group since the last days of the Schism. The fundamentals of the design- namely an elongated hull for crossing rough terrain, multiple independent heavy weapons, and powerful frontal armour make for an assault vehicle whose sheer firepower makes up for its poor manoeuvrability. This particular model is an Emperor Dragon Modern Mark 2c Simplified- the long designation name signifies that it has the easy-to-manufacture hexagonal bolted turret as well as the prototypical light-gas projectors that were typical of the heavier vehicles of its day.
[Twelve minutes omitted. Screaming Dragon sonic attack tank, Spined Dragon tank destroyer, Skyward Dragon missile launch platform, Shield Dragon Infantry Combat Vehicle]
Item 12: Industrious Dragon
[Actor's Recording]
Build that wall. Build it tall. We'll be making it fall before too long.
-Unattributed, Motto of the 1st Engineering Corps, "Breaker Kings"
It is difficult to describe the average Industrious Dragon. Originally designed as an ultra-simple tractor variant of the Roaring Dragon Mk. 1, the lightened, extremely sturdy chassis was rapidly appropriated as the main engineering vehicle of the Ember Group. Because the standard stripped-down chassis was easily modifiable, it became inevitable that engineers, especially those units with trained Metalbenders or those skilled in riveting, would modify their 'Dusties' for a wide variety of purposes. As a result, it came to be a truism of the Engineering Corps that no two of their vehicles would be even remotely similar in design, even if most of the basic components were the same. This particular vehicle from the 1st was used as a tank recovery craft, hence its thickened armour and heavy crane mounting. Dusties were occasionally used as full-on combat vehicles, notably during the Breakthrough, when at least one unit of the 2nd used stolen Norther cannons and flamethrowers to turn their engineering vehicles into improvised bunker-assault vehicles.
Item 13: Tundra Dragon
[Actor's Recording]
The brass called them Tundras. Said they looked like Fire Nation vehicles. Fair enough. But everyone who'd served in one... well, we normally called them something like "Hold together!" or "You [EXPLETIVE DELETED]"
-Tanker Sergeant Oi Hara, Eighth Tank Brigade "Queens of the Desert"
An unusual design, the Tundra Dragon was hurriedly brought into service when it became apparent that the designing of the Spined Dragon tank destroyer was taking too long. The Tundra was a vehicle designed to provide rapid-response support fire in any combat environment. Armed with the same 60mm projector as the Roaring Dragon, the Tundra's chassis was based off experimental redesigns of the primitive Fire Nation 'tanks' of the same name. While the Fire Nation designs' four-wheeled configuration and overcomplicated self-righting mechanisms were inefficient, the idea of a tank which could scale near-vertical cliffs was nonetheless valid. The Tundra kept the same 'wraparound' tread configuration, trading off most of its armour and interior space for engine power. Capable of top speeds of well over eighty milometers per hour off-road, the Tundra Dragon's real failing was that the engine was powerful enough to permanently damage the tracks, suspension and even hull plating if allowed to run too fast.
[Twenty minutes omitted. Failed 'Heavy Walker' prototypes, including OMU Unit-01 and the complete collapse of the Chief Researcher Gonde's OMU Initiative.]
Item 19: Hidden Serpent
[Actor's Recording]
Never forget that it was our submersibles that held the lines against the enemy while our air fleets replaced losses and repaired wounds.
-Admiral Nei Motzu
The Ember group was never a naval powerhouse in the same way that they ruled the air. Outnumbered by the massive fleets of the Fire Nation and the huge water Tulpa swarms of the Lotus, the Group turned to flexibility and mobility to make its sea presence felt. This philosophy, which peaked in the years before the Res War, was expressed in the Hidden Serpent. Not a true submarine or a true battlecruiser, the Serpent is best described as a "submersible cruiser", capable of spending moderate amounts of time submerged and firing torpedoes, while at the same time able to surface and unleash considerable firepower from its six 90mm projectors. Though fast and difficult to kill, Serpents were notoriously unpleasant to serve on- the large boilers needed to run the projector systems, as well as the temperature regulators which kept the powerplant from collapsing in cold water, meant that interior space was very much at a premium.
Item 20: BOOM Serpent
[Actor's Recording]
Projectors? Don't need them. Or the magazines. Or the boilers. Hells, strip out the anti-air mounts, too. If you can't use it to store or fire a rocket, it gets removed. Are we clear?
-Minutes from the BOOM Project's design meetings at Serpent Forge
The Ballistic Ordnance and Operational Materiel Serpent, more commonly BOOM or 'Boomer' submersible began as a cargo variant of the of the Hidden Serpent, until an incident wherein a rocket destined for use on a Skyward Dragon was accidentally set off during an unloading procedure in rough seas. In the aftermath, it was realized that, while the back-blast had destroyed most of the ship's interior, its specially widened, well-balasted cargo-bearing hull had remained remarkably stable. Several months of modifications later, the BOOM had been outfitted with separately sealed rocket tubes and a complicated ventilation system. The entire forward hull could carry up to thirty mid-range artillery rockets which could be independently aimed and fired, but still had the space for a not insignificant amount of cargo. This led to a peculiar system whereby BOOM Serpents would arrive at a theatre as offensive support, but depart as unarmed cargo vessels.
[Ten minutes ommitted. Thunder Serpent rapid patrol craft, history of Ember Group airship design]
Item 24: Soaring Snake
[Actor's Recording]
The heavens fill'd with commerce, argosies of magic sails/ Pilots of the purple twilight, dropping down with costly bales/ Heard the heavens fill with shellfire, and there rain'd a burning dew/ And all the airmen shouted "Lotus? Hey! F*ck you!"
-Graffiti from the Airship Academy. Adapted from Tien Ai Sun's Lay of the Airman.
The Soaring Snake-class airship was to the skies as the roaring Dragon was to the ground- versatile and oft-adapted. A solid, rigid-skinned hydrogen-powered vehicle with eight twin-bladed engines, it could maintain reasonably high speeds without Airbender assistance, and carry a wide variety of combat loads. Though the numerous variants of the Soaring Snake were never classified beyond identification numbers, there were three general schools of variation. SS-A vehicles were equipped with broadside rocket launchers and a mix of light and heavy projectors, SS-Bs were armed solely with rockets and bomb bays for use as bombardment and support vehicles, and SS-Cs eschewed all non-projector armament in favour of troop bays for rapidly deploying Harness-equipped infantry.