2014A: Project Carius (The Thunderbolt MBT)

To beat the Red Army, you need numbers. Thus holds conventional wisdom as well as the experiences of Napoleon’s Grande Armee and Hitler’s Wehrmacht. You. Need. Numbers. Borgundy doesn’t have those. Can’t really get them either, because conscription is gone, and there’s no use trying to go down that road again. Can’t borrow numbers, because the NATO big cheese, America, has a bunch of other commitments in other parts of Europe, not to mention Asia and the Middle East. So, like all powers stuck at a quantitative disadvantage, we’re going to go for a qualitative edge. Hence, Project Carius, which has yielded Thunderbolt, the most powerful tank…in the world. Let’s take a tour.

Sorry, no flash photography.

We’ll start with the main gun, both because it’s a striking aspect of the tank, and because it’s where I started in the design. Most modern tanks use a 120mm gun if they’re good friends with America, or a 125mm gun if they’re good friends with the Soviet Union. Thunderbolt’s main gun is a 140mm L/47 smoothbore. L/47 means its barrel is 47 times longer than it is wide. It’s built for high-pressure rounds, and APFSDS-T rounds from it will go clean through the turret face (i.e. the thickest armor) of any current tank. It’ll laugh in the face of 1,200 mm of RHA steel. If we can hit it, we can kill it. Other less interesting but nonetheless important features of the gun include a protected bore evacuator and a thermal sleeve.

The aforementioned APFSDS-T rounds are somewhat problematic. To get the desired performance, each round is a one-piece unit (no separate propellant charge) that is 1.5 meters long and weighs 40 kg. This mandates the use of an autoloader, rendering crew size debates academic. The large round size also makes internal ammunition arrangements difficult. We’re also very concerned with survivability–we’re building a main battle tank, not a tank destroyer. To maximize crew safety, we’re going to take a page out of the Abrams design and store our main gun ammo in the bustle, beneath blow-out panels. The idea is that we won’t be able to perfectly protect the ammo from enemy fire, so accept the vulnerability and direct the blast outward, away from the crew. Then, we’re left merely with questions of mechanical layout and capacity. Our autoloader system will use a pair of side-by-side, electrically-driven horizontal carousels, each containing 18 rounds. The carousels are isolated from the crew compartment and each other by bulkheads, with small doors that open automatically for rounds to pass through. Rounds are indexed electronically by barcodes, allowing the computer to know how many rounds of each type are remaining. Blow out panels are above each carousel compartment. The twin carousels provide some measure of redundancy, allowing the tank a chance to continue fighting if one carousel is compromised. Other available round types include HEAT and a gun-launched ATGM. This missile insures that the Thunderbolt gives up no range to the Soviet AT-11 Sniper GL-ATGM.

The Thunderbolt has formidable secondary armament as well. Instead of the usual coaxial general-purpose machine gun, the Thunderbolt mounts a 30mm Bushmaster II Chain Gun. This was chosen to maximize stowed kills and increase the number of targets that could be engaged without the use of the main gun. The Bushmaster II is electrically driven, making it phenominally reliable. It’s dual feed capabile, and is compatible with all standard NATO 30x173mm rounds.

The commander’s roof machine gun is a pretty conventional affair. We have an M2-HB mounted in a remote weapons mount, slaved to the commander’s independent sighting unit. This is pretty typical for modern tanks.

The Commander normally observes the battlefield through his independent viewing unit. He has the option of using either day or thermal imaging modes, with 3x, 6x, 13x, 25x, or 50x magnification. He has his own laser rangefinder, as well as optional stadia rangefinding reticles for HEAT or APFSDS rounds on higher magnification settings. The commander can pass targets to the gunner and have the turret automatically turn onto target, or receive targets from the gunner and have his viewing unit turn to the target for additional observation. The commander can also override the gunner and slave the turret to his sighting unit for aiming purposes. He can fire the gun if desired. Additionally, the commander can see the view through the gunner’s sight on his monitor. The commander’s sighting unit has an auto-scan mode if the commander wishes to keep an eye on the monitor while doing other tasks. As a backup observation system, he has eight periscopes arrayed around his hatch to observe the battlefield.

The gunner observes the battlefield and targets on it through his roof-mounted panoramic sight. He also has day or thermal imaging modes, with 3x, 6x, 10x, or 20x magnification. The gunner’s sight also has a laser rangefinder, as well as optional stadia rangefinding reticules for both ammo types. The gunner’s backup sight is an 8x telescopic sight that has been boresighted to the main gun. It can also be used to verify that the gun is clear of an obstruction. Thermal imagers for both the commander and the gunner are dual band units (MWIR and LWIR).

The driver has the usual trio of periscopes providing a reasonable field of view while buttoned up. The center periscope is a combination thermal viewer unit that gives him the ability to operate at night without lights. Additionally, a thermal backup camera is fitted to aid in backwards maneuvering.

The Thunderbolt uses fiber optic cables and a data bus to coordinate information for the computer system. In addition to the aforementioned sensors, the Thunderbolt is equipped with the usual set of crosswind sensors, muzzle reference system, and cant sensors. The fire control computer will automatically compute lead for a firing solution on a target. It is also capable of automatically tracking a target. The computer system can interface with the datalink to share data including position information, maps, planning details, and targeting data with other nearby vehicles. Position data for the current tank is determined by the inertial navigation system, GPS receiver, and a north-finder unit. This data is shared so the crew can view locations of nearby friendly units. Relevant information about status of the tank is also displayed to the crew on the internal monitors.

Actual armor composition and configuration is classified, and details have been removed by the War Office’s Directorate of Secrets Protection. Here’s what they’re willing to let us share. The armor structure has been designed to be fully modular around the turret and hull front. These modules can be easily removed (with a convenient crane) for replacement of damaged modules in the field or simplified upgrades of armor in the most important areas. The turret face armor is a massive 1.3 meters thick, and side armor is approximately 50 centimeters thick. Armor modules on the turret face include depleted uranium. Other materials used include titanium diboride, titanium-aluminum alloys, triple-hardness steel, and nano-crystalline ceramics. In order to allow for a turret face built like the Rock of Gibraltar but not put the Thunderbolt into the realm of stupid-heavy tanks like the Maus, we’ll also need to make some effort to reduce weight. A critical part of this effort is the widescale replacement of RHA steel with titanium aluminum alloys in structural components of both the turret and the hull. This will provide very significant weight savings for no loss in structural strength or protection.

A few other protective systems are of note. First, as is almost obligatory for a modern tank (or a modern refit of an older tank), the Thunderbolt has a spall liner to protect the crew from fragments of hull knocked loose by a hit. There’s the usual modern Halon-gas based fire suppression system for the engine compartment to put out flames as well. Finally, the GALIX system of smoke grenade/decoy launchers have been liberally placed about the turret. These can fire smoke to obscure the tank (and it’s IR signature) from an enemy or incoming missile. These can be fired manually by the crew, or automatically from the laser warning system or missile approach warning system. Finally, the Thunderbolt is also equipped with Rafael’s Trophy Active Protection system. This uses a series of small radars mounted around the turret (also used for missile approach warning notifications for the crew or GALIX cueing) to detect an incoming missile, which is then neutralized by a shotgun-like blast. This provides added defense against large ATGMs.

This took me quite a while to work out. Gas turbines have come a ways since the AGT-1500, and there’s also the French hyperbar V8X to consider. And then there’s everyone’s default choice, the relatively compact MTU MB 883 V-12 diesel. We’re going to go with that V8X. The V8X is basically a hybrid engine that starts life as a rather overbuilt V8 diesel engine, and then went in search of more power. An ordinary diesel engine designer would add one or more turbochargers at this point, but not SACM. Instead, they hooked a mini gas turbine up to the blowers rather than using a tap on the exhaust. Et voila! Massive amounts of extra pressure in the cylinders (a whopping 32.1 bar mean effective pressure). All the power one needs to drive his tank of choice (1,500 hp), along with great torque. Plus, unlike a conventional turbocharger, there is no turbo lag. The massive boost pressure is available immediately, even at idle. The little gas turbine engine can also function as an integrated APU, saving most of the space and weight of a separate installation. Additionally, the V8X has no trouble starting in the cold, unlike conventional diesels. The V8X has somewhat increased fuel consumption, especially at idle, due to the little gas turbine, but it is not as bad as a regular gas turbine. Also, since it does not require the big recuperator or the additional reduction gearing, the V8X powerpack is smaller than the gas turbine powerpack.

The Thunderbolt is designed with an advanced hydropneumatic suspension system. This was chosen because of reduced weight compared to a conventional torsion bar suspension, plus the ability to reduce hull height over a torsion-bar-equipped hull. Hydropneumatic in-arm units are also somewhat easier to replace than torsion bars. Furthermore, the suspension is centrally controlled, allowing the tank’s crew to adjust ride height, or provide additional incline/decline to the main gun. This will allow them to use the terrain more effectively.

Crew: 3 (Driver, Commander, Gunner)
Weight: 65 Tonnes
Cost: $14.2M