Coorsota
02-01-2008, 05:17
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Lariat Main Battle Tank
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Lariat MBT, notice the lack of a RWS and coaxial autocannon
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Lariat 1A1 MBT
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Lariat 1A1 MBT in desert camouflage
Introduction
The M8 Lariat 1A1 Main Battle Tank, or simply Lariat 1A1, is a development of the original Lariat MBT and incorporates several new features and modifications including an entirely new autoloader, remote weapon station, coaxial weapon, fire control computer updates, etc. The Lariat MBT project was started under Allis-Chalmers Defense Services Division, a division of Allis-Chalmers Corporation, and transferred to Sequoia-Allis Defense Services, a joint venture between that division and the Sequoia Automotive Systems subsidiary of Sequoia Defense Systems Inc.
The M8 Lariat MBT project is intended to be a continuous development project focused on continually improving the Lariat MBT through progressive upgrades designed through user experience and feedback, technological development, and prototype testing. All future upgrades are intended to be readily adaptable to the current M8 Lariat MBT frame.
Armament Sub System
Main Gun
Allis-Chalmers Defense Systems Division (now Sequoia-Allis Defense Services) received invaluable experience and knowledge in armament system design and use when it undertook the project to switch out the MCA-7C’s standard gun armament with the AGS 250.A electro-thermal chemical gun purchased from Kriegzimmer. The ETC weapon, the only one of its type in Coorsota, provided invaluable insight into armament design and led Allis-Chalmers to begin developing its own ETC-style weapon. Unfortunately progress on the design stalled as Allis-Chalmers realized it didn't have the technical background or experience required to produce efficient models of ETC-style armaments. The project was put on hold as a potential future upgrade for the Lariat MBT and all progress was instead turned to a conventional smoothbore main gun. Eventually the 120mm G120EGS1 high-pressure breech smoothbore gun was developed, and fielded. The G120EGS1 in its base format for the Lariat 1A1 is 55 calibers in length; compared to the original Lariat’s L/45 main gun, and allows for additional gains in terms of accuracy and round velocity. The gun, when fired, operates on a long-recoil principle reducing the total felt recoil energy on the tank. The entire turret is electrically rotated, resulting in reduced heat and a reduction in volume from hydraulic systems. As will be mentioned later, manual turret traverse and gun elevation are available.
Ammunition
The primary ammunition for the G120EGS1 main gun is the domestically produced Type 19A armored piercing fin stabilized discarding sabot and Type 08D high explosive anti-tank multi-purpose round. Additional types of ammunition are available and can be stored. The Type 19A APFSDS anti-tank round is the standard kinetic energy projectile of the Ground Defense Force and fires a rippled depleted uranium projectile weighing 10.0 kg (penetrator weighs only 5.1 kg) from the barrel at a velocity of about 1,650 m/s (using the standard G120EGS1 barrel). The rippled designed lessens drag, allows for some flex in the design (with a ‘softer’ metal at the thinnest portions bonded by a polymer sandwich), and reduces the effectiveness of certain ERA types. Due to advances in propellant design, and using the extended barrel, the Type 19A can reach out to almost 4,000m. The Type 19A’s HEAT-MP counterpart, the Type 08D fires an 11.5 kg projectile at about 1,400 m/s to achieve an effective range of almost 4,500 m. The Type 08D’s warhead is sub-caliber with a discarding sabot and fragmenting outer jacket and is also capable of multiple fuzing options, including airburst. An additional ammunition option is the M40A1 barrel-fired anti-tank guided missile. The M40A1 is designed to be fired from the Lariat MBT’s main gun and utilizes a semi-active laser homing system. The missile is guided by laser – provided by either the tank or another platform (another tank, helicopter, UAV) and is capable of multiple engagement options. The top-attack option allows the tandem-warhead missile to angle up before descending on its target and during its terminal phase the guidance portion of the warhead (used to detect the laser radiation) is ejected off towards the target. This is designed to trigger an opponent’s active defense system, if equipped, and allow the twin warheads to strike the vulnerable upper armor of the tank. It’s effective range is about 12 km.
Autoloader
The Lariat 1A1 uses an entirely new autoloader design compared to the previous S120GAL0 bustle-type linear ramming-action autoloader. In its place is the S121GAL1, or Sigleuir 1VXB by trade-name, drop-shelf type bustle linear ramming-action autoloader. The S121GAL1, sometimes affectionately referred to as ‘Panzervergewaltigen Faustladevorrichtung’, is a fast action bustle-based 42 round ramming action autoloader.
The 1VXB Autoloader was engineered at the Sigleuir Prototyping and Experimental Design Division Facility as a fast action, high reliability, and relatively inexpensive autoloader design contracted by Coorsota's Ground Defense Forces for the M8 Lariat 1A1 MBT. It is a 120mm autoloader design based off the IPR-201's Drop-Shelf Type Bustle Linear Ramming-Action Autoloader, but optimized for the production budget of the Republic of Coorsota's M8 Lariat 1A1 MBT. In 9 days, a working prototype design was tested in a mockup turret rig, consisting of a turret ring stand with an electrical power supply adapted to it, a turret with many internal similarities to the M8 Lariat 1A1 MBT, and with a supplies of simulated shells that would be then loaded into the breech that would drop them into a small collection basket. The turret test bed was created to prevent design conflicts between the actual tank and autoloader integrations, often found in many forms of "cut and paste" jobs, where components are "dropped" onto a tank, then "stapled" to it, with minimal care to conflicts that occur from the physical level to the ergonomic level. In the end, very few revisions were made, specifically noting that the autoloader indicator system was integrated to the tank's viewfinders, and the autoloader ammo tracking system had its own LCD added. In addition, the gunner and commander's multifunction displays are integrated with the ammo management end of the autoloader.
When the gunner or commander, with priority to whoever has ammo selection, presses the selected type of round, the autoloader will proceed to start into cycle one (for estimated time of cycles and operations, see below), where the system will proceed to test its components to ensure the proper operation by operating parameters, then proceeds to move the round selected from the six "shelves" to the ramp, which will adjust its height to allow for this, then locks it into place, waiting on the blast door and external ramp. Cycle two is primarily on the process of the ramp extension and ramp tilt. After this the autoloader will proceed to move to cycle three where the round, within its armored box, will be pushed outwards from the bustle toward the first ramp where it locks into place while the round is inserted into the gun; this will then proceed to allow the ramp extension mechanism to release the latching mechanism of the armored box, so that the box can collapse as the rammer proceeds to retract. On cycle four, as the rammer and ramp retract the box is dropped and the gun is unlocked to be prepared for firing, waiting for the ramp to fully retract to prevent collision during recoiling from firing. The autoloader completes these cycles in about 1.8 seconds, with 2 seconds being the longest wait based on the capacitor charge. The capacitor has the capability to operate the rammer up to three times before having to be fully recharged from zero. An addition to the autoloader is the capablity to operate it rapidly in manual mode, where the gunner would be able to operate the autoloader through selecting the cycle one by lever, and then rotating the hand crank system which is linked to a mechanically automatic gearbox which also can be selected to a 1 to 2 fixed gear as a backup. The gunner would then advanced through the cycles in 6 seconds, going from cycle one to two and then having the ramp and rammer starting to retract in cycles three to four. This system allows for fast, efficient loading operation. The ammo selection is handled, however, by using a second hidden panel, which is opened, where L1-3 and R1-3 is marked, with a lever pointing to each letter-number combination indicating the shelf selected. A rotating hand crank is then used on that side to push the round in, causing the rotating indicator to go from the red to the green on the cycle crank.
The autoloading system can be loaded from internally in the tank, where the round is inserted through the same blast door in its armored container, and then the autoloader will automatically read the round type by the indentations on the shell rim. The autoloader will then proceed to raise the ramp to the right level and insert it to the proper shelf. The manual operation can be done as well through using the selection crank, and sliding the bottom switch from "Load Gun" to "Load Autoloader", and then rotating the hand crank to move the ramp into the proper shelf height and moving the round into the shelf before locking the internal blast door and ramp into the normal position again; the same green-red indicator used on the manual operation of the autoloader is used to confirm if the cycle is completed. External loading is completed by unlocking the external hatch from the inside, then pulling it outwards from the rear center of the bustle. After this, an internal hatch will be revealed, which can be pulled open by grasping the handle and pulling upwards, which will reveal the inside of the autoloader ramp from the top. Rounds are inserted from the rear, within their armored boxes to load to the autoloader, the same manual process can be completed or the automatic process. The ammo management computer can be used to specifically pick which "shelf" the round type will belong to.
The autoloader has full venting paths through the sides, if any form of penetration should happen, combined with the fact of individually armored ammo boxes that prevent ammunition fratricide. The autoloader itself is armored to prevent up to 35mm autocannon penetration, combined with the bustle armor that the tank already has. Combined with internal mounting points for 18 Halon bottles (3 bottles per shelf, which can be manually fired, or automatically fired as separate bottles or as a group), as well as blast door separation. The autoloader has great fire fighting capablity, and if that were to fail, the venting paths also prevent each "shelf" from going up, minimizing ammunition fratricide to a maximum of seven shells per shelf level combustion. Not only does the autoloader have crew separation to ammunition while autoloading, it has its own self contained NBC system with air conditioning to ensure that no matter what form of penetration entering the autoloader, no entry into the fighting compartment can occur.
Each round is within a collapsible box with 1CM thickness on all sides for 150mm diameter (shell diameter, not actual round diameter) by 1,000mm long rounds. With complete immunity to small arms fire and extreme resistance to .50 anti IFV/APC and anti-air fire, followed by moderate resistance to 25mm AP-I or HE-T rounds. The armored box also has venting paths to prevent ignition fratricide, combined with its natural heat resistance shielding the round. The box its self can be collapsed into flattened parts after removing the retaining latches, similar to cardboard boxes; this is combined with the tank's autoloader where it automatically handles the storage of the empty boxes, which can be reused. Autoloader capacity of forty-two rounds determined by: three stacked levels in height (three ‘shelves’), two sides (left and right with center being occupied by ramming system occupying 200mm), and seven rounds per side of each shelf.
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Secondary Armament
In addition to the tank’s main gun, the Lariat MBT carries a coaxial G25AGS2 25mm autocannon and 1500 rounds of ammunition as standard equipment. This was possible after some internal modifications were made, mostly resulting from the use of a new autoloader and other internal features which freed up additional space. The upgraded gunnery allows the tank to better engage IFVs, APCs, and other targets without utilizing its main gun ammunition and which may be out of range of a conventional 14.5mm machine gun.
The commander’s position in the Lariat 1A1 upgrade comes standard with the A141RGS1 Commander’s Remote Weapon Station. The A141RGS1, better known as ‘the Rifleman’ (for the remote weapon stations’ designation’s {A141RGS1} supposed resemblance to Adrian Riggs’ name, a popular Coorsotan film star who played ‘the Rifleman’), is a large multiple-weapon capable remote weapon station that serves not only to give the commander an independent ability to engage targets from within the tank but also serves as his ‘heavy’ independent viewer. It was designed to be an ‘add-on’ feature and not require extensive modification of the turret or interior of the tank. To this end, the Rifleman RWS requires little modification of the Lariat 1A1 turret and most of its components are mounted exterior to the armor. The Rifleman remote weapon station provides all the same electronics system as the TS/EQ-31A Commander’s Independent Viewer only in a larger, more rugged format. This includes the commander’s laser rangefinder/designator, thermal imager, and day/night optics. In this situation, the Rifleman has largely replaced the TS/EQ-31A for the commander’s purposes; however, the TS/EQ-31A is retained as a back-up and to give the gunner an auxiliary imaging system in place of his primary sights and backup systems. Besides this, the A141RGS1 has the ability to mount several types of weapons from the MG4 light machine gun all the way to the G20AGS2 20mm autocannon (requires modification), however the MG5 14.5mm heavy machine gun is mounted as standard fare for the Lariat 1A1 and fulfills its purpose well as an anti-personnel, anti-helicopter, and anti-light vehicle tool. This lethality can be expanded on by adapting the Rifleman RWS with an ATGM launching system. This pack, armored up to light machine gun ammunition, carries two anti-tank (or anti-aircraft provided they are small enough) missiles in a shuttered, ready-to-fire pack, giving the Lariat 1A1 the ability to engage tanks at extended ranges, although the gun-launched ATGM is already capable of this. Light anti-aircraft missiles are also capable of being utilized with this system and are often found useful scattered in deployed Lariat 1A1s, creating a hazardous environment for opposing aerial assets.
An interesting addition to the Rifleman remote weapon station is a portion of the CQ-29 active defense system, particularly, the grenade launcher systems and part of the millimeter wave radar component. Among the benefits of this arrangement: the engagement distance is increased by around a meter, the whole Rifleman RWS can be used as a sort of close-in defense system and not only engaging the threatening warhead/missile but also engaging the launch point of that threat. Ammunition for the remote weapon station, depending on the type of the weapon, is fed from within the tank and can be reloaded from within the tank provided that a new belt is attached before the old belt has left the interior of the tank (often, the crew will link two or more belts immediately to save them from having to do this after firing only ten or fifteen rounds).
The final weapons system is the gunner’s weapon mount which can be fitted to use a light machine gun.
Defense
Armor
The armor scheme of the Lariat Main Battle Tank was developed from materials, ideas, and examples provided by the Advanced Materials Education Coalition (AMEC) of Larange State University and the Knife Point Technical Institute. Allis-Chalmers contacted AMEC in regards to the educational consortium researching and developing advanced materials intended for use in armor of a main battle tank. Larange State University, being a state university, opted not to participate in the research phase but did allow the use of previously researched materials and techniques to be used by the research group from Knife Point. The Knife Point AMEC developed the “Cuera” armor scheme for use in the Lariat MBT and subsequent variants. The Cuera armor system is composed or largely common materials arranged in a specific format which provides a startling amount of protection for the thickness and weight of armor but without inducing exorbitant costs for exotic materials. To this end, the Cuera armor layout is as effective, or more, than most expensive, composites-augmented armors. The Cuera armor scheme is composed of the following layers, beginning with the outermost layer for the turret face and glacis:
Primary Armor (600mm real thickness; Spacing through out the design results in a real thickness between 650-700mm)
• 150mm high hardness monoplate steel
• 20mm rubber plate
• 10mm plastic plate
• 20mm rubber plate
• 100mm section of steel plates of 20mm thickness at 45 degree angle standoff from each other at 20mm with reactive polymer that quickly solidifies from HEAT or pressure
• 50mm depleted uranium
• 50mm hard monoplate steel
• 50mm rubber
• 50mm hard monoplate steel
• 50mm soft monoplate steel
• 10mm hard monoplate steel
• 10mm soft monoplate steel
• 30 mm rubber
The varying thickness and density (either soft or hard) steel plates induces yaw into a penetrating KE projectile, potentially even shattering it. The turret face armor is angled at 30 degrees from the vertical and 12 degrees from the horizontal. Turret side armor is angled at about ten degrees from the vertical.
Following this is the 100mm spall liner, composed of densely packed fibers within a rubber enclosure within a plastic box. The face of this box towards the armor side is 5mm steel and rubber plates for 50mm. In addition, all interior metal surfaces are first covered in a plastic panel then painted with a rubber-like non-slip paint surface.
Armor on the turret sides is effectively similar only slightly reduced thicknesses and reduced spacing. Armor on the back of the turret and hull is reduced by removing the 100mm section of angled steel plates and the 50mm soft/hard monoplate sections (400mm). Roof armor is between 150-250mm real thickness using a similar construction scheme. Most of the exterior armor is coated in a non-slip layer.
To defend against a land mine threat, or a triggered explosive threat, the underside of the hull utilizes a similar version of the tank’s overall armor to help defeat high explosive land mine and other threats. This spaced and heavily layered armor, although thinner and lighter in overall construction, aids considerably in the defense against a large portion of mines and some improvised explosive devices. To augment the armor in defending the crew, the crew’s seating is further armored with titanium layers and an additional spall liner. Placement of non-critical components between the initial armor and hull-underside spall liner provide some additional protection.
Vaquero ERA
The Vaquero ERA system was designed using data from the Advanced Materials Education Coalition, Allis-Chalmers Defense Services Division, and independent labs and entities across Coorsota and abroad. The Lariat MBT’s optional explosive reactive armor was designed to combat most munitions encountered on the battlefield today and originally intended to be equal to most available types of explosive reactive armor. ERA research in Coorsota started with the arrival of the MCA-7C Timber Wolf MBT in order to develop a possible ERA package for the tank. Progress was slow however but produced a working, if basic, ERA system. Allis-Chalmers, with federal aid, funded several additional research and development programs at universities (explosives research) and private labs (ERA design and implementation) to eventually produce the precursor to the Vaquero ERA. With the initialization of the Lariat MBT program, design was halted on fitting the ERA to the MCA-7C and it was instead brought back to the research and development phase with the intent to modify and fit it to the Lariat main battle tank. This project resulted in the Vaquero ERA system. The Vaquero ERA is a layered system composed of the following layers besides an initial ceramic outer layer (to defend against the initial warhead of a tandem-warhead weapon) and a steel/ceramic backing:
• Layer 1: Trigger in very front, plate behind, and explosive below, which alternates for the second plate, inverts again for the third plate, and again for the fourth plate. When a HEAT jet or KE penetrator triggers the ERA, the first layer of that portion of the ERA will detonate and the explosives on the bottom will push the plate up (or roughly perpendicular to the jet/penetrator's line of travel). If the jet/penetrator penetrates that plate, the explosives on the second layer will push the second plate downward and so on. This serves to 'feed' the plate into the jet or penetrator from both top and bottom at different depths of penetration. This'll feed material into a HEAT jet eroding its effectiveness, and depending on the composition of a penetrator (especially the narrow diameter/long rods) potentially snap it or create some yaw, at least before it reaches the final ERA layers.
• Layer 2: This is a thinner rubber-polymer-steel layering which induces yawing in KE projectiles and further impacts a HEAT jet.
• Layer 3: This is the heavy ERA component of the Vaquero ERA system and is designed to specifically eliminate the KE threat by using shaped charges to induce more yawing in addition to dismembering the penetrator. Heavy blast layering behind this is formed in a way so that if triggered, it will likely crush any remnants with its faceplates and explosive pressure.
The entire system is encased in resin.
Countermeasures
The Lariat MBT was originally designed to carry only a basic set of countermeasures, mainly grenade launchers (to launch smoke grenades, aerosol canisters, or chaff) and a smoke generator. However, as development wore on, additional features were researched and available for the initial production model. Allis-Chalmers engineers took the next step and combined all the countermeasures features into a single unit to ensure the survival of the tank against a wide assortment of threats. The basis of the SS/CQ-10A combined active/passive countermeasures system is the smoke generator found near the diesel engine and grenade launchers (8x with 2 canisters per launcher; can fire chaff, aerosol, or smoke). These are capable of operating independently under crew control or with the SS/CQ-10A system. Beyond this is the component CQ-29 mast-deployed active protection system and is designed to combat most missile threats. The CQ-29 is not a single system but is rather both active and passive and utilizes soft-kill measures to assist its core hard-kill system. Threats are located using a passive thermal imager as well as an active radar system, and these can operate with the tank’s primary systems. Using infrared jammers, electronic interference, chaff/smoke/aerosol launchers, smoke generator, or decoys, the CQ-29 will attempt to ‘soft-kill’ the threat, if this is unsuccessful in completely eliminating the threat, the CQ-29 will resort to its hard-kill system. When this determination is made, the CQ-29 will shutter the primary optics (the primary forward looking infrared, RWS, and the commander’s primary thermal imager; leaving backup imagers and optics) and the hard-kill system is activated and fires explosive packets at the incoming target.
The third system is simply a threat warning system designed to allow the crew to rapidly engage an ATGM crew, and if configured to do so, will automatically align the RWS to the ATGM launch point and allow the commander or gunner to engage the target.
Fire Control
The Lariat MBT’s fire control system is composed of a number of systems which operate in unison to provide the crew with an unobstructed battlefield view and maintain their awareness of their surroundings. In addition to the optical periscopes positioned around his egress hatch, the commander is given an independent periscope with an LCD information overlay (TS/PQ-12A) and independent thermal viewer TS/EQ-31A. The two systems provide 360 degree target identification while the thermal viewer is enhanced with a day/night camera for higher-resolution non-thermal imaging and identification as well as a commander’s independent laser rangefinder and designator. Output from the TS/EQ-31A is displayed on a multifunction LCD monitor in a stabilized mount, and can appear on the LCD optronics overlay on the TS/PQ-12A. The TS/EQ-31A’s output can also be transferred to the gunner, allowing the gunner access to the same field of view of the commander (and vice versa).
The gunner’s station is fitted with an FC/TQ-7A1 dual magnification stabilized primary sight. The FC/TQ-7A1 has an integral laser rangefinder and is mated to a Sheyenne Technologies Group OsprEye II forward-looking infrared imager (with a smaller, lower resolution backup imbedded in the turret on the other side of the main gun). The OsprEye II is a new addition with the Lariat 1A1 upgrade and represents a leap in design technology over the original OsprEye forward-looking infrared imager. The new unit features a polarization-sensitive focal plane array with etched polarization elements integrated to each imaging pixel. The OsprEye II allows for greater target detection by exploiting infrared polarization signatures and enhancing the contrast of targets versus backgrounds. In addition, the OsprEye II carries an uncooled indium gallium arsenide (InGaAs) shortwave infrared imager to better defeat optical camouflage and to provide another layer of information for the fire control system to process into a compound image for the gunner/commander. The InGaAs SWIR imager is also capable of seeing most laser rangefinders, specifically those in the eye-safe range. The FC/TQ-7A’s laser rangefinder is a Neodinium Yttrium Aluminum Garnet (Nd:YAG) solid state laser and can provide up to five range values in three seconds. Augmenting this is an electro-optical rangefinder which uses a camera to focus in on its target. To focus, the lenses are moved apart and once the tank is in focus, the range is determined by taking a value associated with the distance the two lenses are apart and using that to derive the range to target in 5m increments. This allows the tank to find the range of an enemy tank while emitting no laser radiation (and tripping a laser warning receiver) and is particularly useful in the first engagement. The range data from both systems is transmitted to the fire control system via fiber optic link and is used to calculate firing algorithms. The gunner, and commander, both have access to the laser rangefinder. The commander’s rangefinder also serves as a laser designator with a variable power setting. Maximum laser range is ~12km.
A laser imaging system, such as LADAR or LIDAR, was originally planned to be fielded in the Lariat main battle tank. However, introduction of a LADAR system would have compromised the tank’s ability to operate passively, as the LADAR system, through its laser imaging system and intermittent laser pulses, would essentially serve as a targeting beacon for enemy tanks with laser receivers/imagers. Instead, the Lariat and Lariat 1A1 are fitted with the ES/WQ-1B Common Warning Receiver. The ES/WQ-1B is composed of several RADAR and laser warning receivers located around the vehicle to provide full awareness. Four imagers are located on the sides of the turret with two looking forward and two looking aft, each covering a 90 degree arc, and are designed as a higher resolution laser warning receiver, capable of lending information to the fire control system to engage targets employing an active LADAR system.
Updated with the Lariat 1A1 upgrade package, the Cortronics CS/TQ-3A is the system that ties all the imaging systems together and produces a fire control solution for the main gun. A composite image of the target is created using the electro-optical and imaging infrared (long wave/thermal and short wave) imaging systems. The composite image provides better target definition with warm and cool spots being directly referenced with the non-thermal images gathered by the SWIR and visual (low light) imaging systems, defeating a large number of optical and thermal camouflage patterns. The CS/TQ-3A directly controls the main gun and provides fire-on-the-move, stabilized operation with high accuracy and efficiency. The system is capable of being locked onto a target to maintain a continuous fire control solution. A queuing system is available to the commander to designate and queue targets for the gunner, allowing up to ten simultaneous targets to be queued and tracked. The system operates using a single hard-drive hard storage system in a shock absorbent casing but actively uses only solid state memory devices during actual operation; this prevents hard maneuvers, hits, and roughness from damaging the tank’s memory. When the tank is shut down, the solid state memory transfers to the hard drive until the vehicle is started. Both forms of memory, solid-state and hard-disk, are capable of being upgraded to any size necessary to carry out all the functions required by the crew and fire control system. Finally, all crewmembers are given at least one multifunction LCD display. All electronics are shock and jolt stabilized.
In addition to the actual imaging and fire control systems, the CS/TQ-3A carries several other features to assist in the tank’s operation. The fire control system of the Lariat 1A1 MBT maintains a standing record of the current lifetime of the barrel and how many rounds have been fired through it. When the breech is opened and the shell has been extracted, a small laser measures the interior barrel diameter and its change from the previous scan. The fire control system then uses this data, in addition to a stored barrel wear spreadsheet (with expected wear values), to compensate the fire control solution for barrel wear. Finally, the fire control system computes and accounts for air temperature, humidity, target velocity/direction, tank velocity/direction, wind velocity (using a cross wind sensor), barrel temperature, muzzle reference system, and other factors in its fire solution. Besides updated bussing systems, computer components, etc. the Lariat 1A1’s CS/TQ-3A includes a new system designed to allow the tank to better engage known threats. Using the tank’s upgraded solid state and hard-storage systems, the Lariat 1A1 now has the ability to store target information, specifically thermal image characteristics and useful information of certain tanks to aid the Lariat 1A1 in the proper identification and best course of action to take when engaging a tank of a certain model. One interesting feature of this functionality is the ability to program the fire control system to aim for specific ‘weaknesses’, whether these be actual physical weaknesses (such as reduced armor, design attributes, etc.) or weaknesses in capability (such as programming the CS/TQ-3A to take advantage of an opponent’s lower-ranged gun, or sensor deficiencies), although in the former case, this depends largely on range due to the circular error of probability of actually hitting a small area on a tank while in motion on the battlefield. This system also maintains a standing catalogue of engagements (storage space and tank survival permitting) including most of the conditions encountered during firing and whether or not the hit was successful on the tank.
The TS/FQ-101A is a fire control subsystem designed to be used in a high-threat environment. In a typical combat situation, if a tank is struck, the chances of that tank recovering from the impact in time to fire a shot to defend itself is relatively low, allowing the opposing tank to load and fire a second round. The advantage often goes to the tank that can fire, and hit, first. A single shot that is not enough to disable the Lariat 1A1 but invariably affects the crew and other systems, creates a few moments of ‘down time’ and gives another enemy tank the chance to quickly follow up and disable the Lariat 1A1 MBT. The TS/FQ-101A levels the playing field, partially negating the opponent’s advantage in firing first. When in a high threat environment, the gunner presses an ‘arming’ button as he’s adjusting the tank’s solution on the target and preparing to fire. In a situation where the Lariat 1A1 can fire first, the gunner will depress the trigger and the weapon will fire. However, if the Lariat 1A1 is struck before it can fire and the impact/damage is enough for the gunner’s hand to leave the control (and if the damage does not seriously affect the core fire control and gun systems), the Lariat 1A1 will automatically engage the target the gunner was locked on to. Once the round is fired, the autoloader will cycle in a new round. By about this time the gunner, unless he is incapacitated, should be able to resume operational control over the main gun and fire control systems. If he is incapacitated, the commander can take control of the main gun.
The gunner and commander of the Lariat 1A1 MBT are each given something considered antiquated to most current tank crew – a completely analog fire control system augmented by a size/range comparison plate with a provision for a secondary laser-rangefinder. A mechanical computer is also provided. The analog fire control systems were added to all in-service MCA-7Cs due to a common criticism of the tanks’ fire control and targeting systems in relation to the sometimes very rough terrain encountered in Coorsota. Most problems occurred during trials or training exercises when the tank in question was on the move and preparing to fire on a target, and hit a rock ledge. The subsequent impact and jolt, although not enough to actually damage the tank, did its number on the sensitive electronics within, often knocking out one or more LCD screens and partially disabling some fire control systems. From this point forward, the tank couldn’t effectively fire its main gun until the tank could be serviced in the field. The experiences led to the shock-dampening of all electronics in the Lariat 1A1 MBT, including all monitors in cased in a shock absorbing cradle. The completely analog fire control system including manual gun elevation and traverse, would allow the tank to effectively operate without power to the turret control systems, when the primary and secondary fire control systems are disabled, or when the tank wishes to remain hidden yet still engage a target.
In addition to the above fire control and electronics, the Lariat 1A1 MBT carries the Cortronics VRC-9661 multiband, multimode tactical vehicular radio which provides HF (2-30 Mhz; long range strategic communications) and V/UHF (30-512 Mhz; short range tactical communications) radio communications ability in addition to digital communications between tanks (such as sharing firing data or coordinates, etc.). The system also provides inter-tank communications between the driver, commander, and gunner. In addition to this, the system’s “field telephone functionality” is diverted to an externally, rear mounted phone system which allows supporting infantry to use the communications system to communicate to the tank’s crew or to communicate with any other unit (from tanks and aircraft to infantry) within range. Finally, the VRC-9661 provides a GPS connection to allow for both satellite communications (if equipped) and geolocating abilities.
Mobility
Introduction
The D990AGP1 is the result of a mid-life engine upgrade program to increase the D900AGP2’s fuel efficiency and power density to an extent, however, the D900AGP3, as it was known at the time, slowly evolved into an entirely new engine: the Sand Draw Diesel (or SANDIESEL) D990AGP1. To this end the previous engine’s common rail fuel injection was replaced with a new common rail system using piezoelectric crystals in place of solenoids in the injectors and provides an instantaneous response for fuel injection. An additional feature was added, as a result of the injection modification, which allows for greater use of available air in the cylinder. The sequential turbochargers were modified with ceramic turbine wheels to provide lower inertia and a faster response time to load. The conventional barrier-filter filtration system was replaced with a pressure-side filtration system with the primary filter downstream of the turbochargers and a pre-filter upstream. And finally, an electromechanical valve train was added to give full control of all engine functions to the Central Electronic Control Unit.
Engine
The D990AGP1 is a liquid cooled multi-fuel capable twelve cylinder (four valves per cylinder) sequential turbocharged four-stroke diesel engine displacing 28L (1708 cubic inches; 150mm x 132mm bore*stroke). The diesel engine is controlled by a Central Electronic Control Unit (CECU) which observes and regulates every major action of the engine including varying turbocharger pressures, valve timing, direct injection properties (injection timing, duration, fuel amount), etc. and can optimize the performance of the engine for several preset modes from which the driver or commander can choose from: the two major modes being performance and efficiency. The engine mode can be switched during any moment of the engine’s operation and crews may ease fuel consumption during transit with the CECU set to efficiency and when preparing for battle, switch to performance. The CECU also provides advanced diagnostics to the crew of the tank during operation as well as to repair personnel when the engine is in need of repair.
The CECU-controlled common rail fuel injection system operates the fuel injectors using piezoelectric crystals. This allows for a more precise control of fuel flow to the engine and permits the fuel flow to be controlled four times more quickly than the previous system. Additionally, the new system incorporates a ‘pilot injection’ feature which, prior to the main injection, releases a small, pilot amount of fuel to initiate the combustion process without the dramatic peak in the heat release rate compared to a conventional fuel injection and ignition process (allows the air in the cylinder to be better utilized). Using less than ten percent of the injection fuel in the pilot injection (determined by the CECU), this system reduces NOx by approximately 35 percent and smoke by 60-80% without worsening, and actually improving, fuel efficiency.
The traditional mechanical valves, cam, rockets, etc. on the D990AGP1 are replaced, entirely, with an electromechanical valve train system (EMVT). With the EMVT system, the traditional poppet valves are operated by electromagnets positioned above the valve guide, effectively doing away with the mechanical cam and rocker system. The valve is operated through two sets of magnets, one above and one below an armature on the valve stem above the cylinder head and within the EMVT housing. For air-intake or expelling exhaust, the lower magnets are electrified and pull the plate downward thus opening the valve. When the valves should be fully sealed for compression and ignition, the upper magnets are electrified, the plate is pulled upwards, and the valve is sealed. Two springs, one above the assembly and the other below, recessed into the cylinder head between the assembly and head, maintain tension and when the engine is off, keep the valve in the half-open position. The system allows for fully variable valve timing (including faster valve-to-seat velocities: below .05 m/s) and superb integration with the advanced direct injection systems already employed by the D990AGP1 engine. The ability for the engine computer to vary the valve timing and duration-of-opening allows for greater fuel efficiency, improves cold-start and warm-up behavior, etc. especially in conjunction with the other features involved in the D990AGP1. Additionally, repair is facilitated due to the easily-replaceable nature of the single EMVT system for each cylinder head and requires no tuning beyond plugging into the CECU.
The pistons are composed of high-strength steel with a symmetrical shallow-bowl head design that works in conjunction with multiple injections of fuel and twin intake valves to boost compression. Higher power densities result from this combination. Air filtration is now provided by a ‘pressure-side’ filtration system which uses a more compact filtration component positioned downstream of the turbochargers with an up-stream vortex tube prefilter. The new filtration system results in less than half the volume of the previous barrier-filter filtration system and less engine gas exchange loss if there’s a blockage in the filter.
The D990AGP1’s turbocharging system operates as a sequential unit with two independent ceramic-wheeled turbochargers working in tandem. The first turbocharger compresses combustion air as usual. Exhaust is directed to a second turbocharger downstream from the first. The energy from this second turbine transfers to the crankshaft and offers multipoint efficiency gains (~3-5%). The new ceramic turbine wheels allow for lower inertia and thus a faster response time to load. The ceramic face now also functions to protect the turbine wheel in the face of particulate matter between the pre-filter and primary filter of the air filtration system.
The crankcase offers structural ribs to increase the crankcase’s life, improve strength, and reduce operating noise. Crankcase oil is now cooled through pipettes to decrease operating temperatures. A grid block/head heater and fuel preheater provide cold weather starting ability in addition to the CECU’s ability to adjust operating conditions. A muffler and combined radiator system are also present.
Together, all of these features allow the D990AGP1 to produce 1230 kW (1650 HP) in addition to a power reserve of 115 kW at 1,800 RPM. The engine also produces a 40% torque rise (from lowest available torque to highest available torque) at 1,400 RPM. Maximum torque is ~4400 Nm. No governor is present beyond the CECU’s moderation. Instead crews are trained to maximize fuel economy when required. This allows the full breadth of the engine’s power and capability to be used when needed. Warning and predictive diagnostic systems are present to alert the crew to dangerous conditions if they proceed to push the powerplant systems too far.
Auxiliary Power Unit
Using experience from adopting the MCA-7C Timber Wolf, Allis-Chalmers designed an under-armor auxiliary power unit for use on the Lariat 1A1 MBT. This 32kW diesel turbine allows for the primary systems of the tank to function without using the main engine and wasting unnecessary amounts of fuel (as well as lay in ambush with a reduced heat signature).
Transmission
The drivetrain is rounded out by a Western Motors designed T250FGT1 transmission component. Originally, the Lariat 1A1 MBT was to be fitted with a similar, automatic transmission. However, in component testing where the transmission was instead used in a converted M-60 MBT, the automatic proved to be troublesome. Proper crew training, however, alleviated the majority of these problems except for the transmission’s capability to serve in a ‘tractor’ role, such as towing other tanks. The Ground Defense Force required that a tank be able to also serve as a recovery unit for other tanks if a dedicated recovery vehicle was not around, and the automatic transmission was ill suited for this task. Instead, Western Motors produced a similar design which uses a series of primary gears, eight in total, and each with its own range of three gears. This completely manual system would allow the driver to select an appropriate gear for the task at hand, and have the capability to upshift or downshift to meet the power requirements of the task. During testing, the transmission when placed in first gear (up to third gear depending on the medium the tanks are operating in) had no problem pulling a similar-weight tank, and the driver could then shift between three ranges in this gear, going from 1-1 (creeper) to 1-2 and then 1-3 (and back again) with the motion of a single lever and no clutch. All gears can be shifted into from a standing point, with the upper four gears requiring little or no load and designed primarily as maneuvering or road gears. Fourth gear was optimized as a ‘battle gear’ and provides quick acceleration with the throttle and smooth gear transitioning. This gear can operate under some load in less-than-ideal terrain (such as in snow or light mud). The modified T250FGT1 provides reduced maintenance over its automatic cousin, improved fuel economy, improved performance in some areas, and the ability to serve as a recovery, or even engineering, vehicle. The T250FGT1 is a compact automatic transmission which features an infinitely variable hydrostatic-hydrodynamic steering system, combined braking system, infinitely variable cooling fan, high efficiency, digital controls for some functions (using a derivative of CECU), and provides easy operation to the driver and repair to maintenance personnel. The transmission is mounted parallel with the engine and entire engine/transmission package is capable of being removed together using a built-in rail assembly facilitating quick replacement or repair in field conditions.
Suspension
The Lariat 1A1 MBT's suspension was designed, like the rest of the tank, for Coorsotan terrain. Thus, its suspension is capable of adapting to Coorsota's widely varied terrain - from rolling plains to the more ubiquitous rocky foothills. The suspension is largely hydraulic with swing arms designed to give the road wheels a generous amount of movement and soften the motions of the tank so the fire control system has an easier time at compensating for the movement. The suspension is also partially active, allowing for the ride height of the tank to be adjusted (such as positioning the suspension to give a greater hull-down capability). Road wheels, track supports, idlers, and drive sprockets are all composed of high strength steel. Road wheels have a layer of rubber to reduce wear to track links and to the wheels themselves.
Miscellaneous
The Lariat 1A1 MBT can serve as an emergency recovery vehicle with no threat of damage to its drive train and thus carries the mounting points and tow hooks required to be able to tow and recover other main battle tanks in lieu of a dedicated recovery vehicle. Heavy duty tow cables and chains are carried in addition to straps for recovering smaller vehicles.
Finally, the Lariat 1A1 maintains the ability to carry external fuel stores. These external fuel stores, however, are not drum-type but instead a box-style system hung over the muffler system on the tank and not directly visible from the forward arc. They are self-sealing and partially armored against most small arms fire and shrapnel. Due to their built-up nature, they are usually recovered later. The fuel boxes can be jettisoned from within the tank. A drum-type external fuel system can also be used.
Additional Information (Versions, General Specifications, Contractors, Exports, Sales/Pricing, and Additional Images) Below! (http://forums.jolt.co.uk/showpost.php?p=13338447&postcount=2)
Lariat Main Battle Tank
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Lariat MBT, notice the lack of a RWS and coaxial autocannon
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Lariat 1A1 MBT
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Lariat 1A1 MBT in desert camouflage
Introduction
The M8 Lariat 1A1 Main Battle Tank, or simply Lariat 1A1, is a development of the original Lariat MBT and incorporates several new features and modifications including an entirely new autoloader, remote weapon station, coaxial weapon, fire control computer updates, etc. The Lariat MBT project was started under Allis-Chalmers Defense Services Division, a division of Allis-Chalmers Corporation, and transferred to Sequoia-Allis Defense Services, a joint venture between that division and the Sequoia Automotive Systems subsidiary of Sequoia Defense Systems Inc.
The M8 Lariat MBT project is intended to be a continuous development project focused on continually improving the Lariat MBT through progressive upgrades designed through user experience and feedback, technological development, and prototype testing. All future upgrades are intended to be readily adaptable to the current M8 Lariat MBT frame.
Armament Sub System
Main Gun
Allis-Chalmers Defense Systems Division (now Sequoia-Allis Defense Services) received invaluable experience and knowledge in armament system design and use when it undertook the project to switch out the MCA-7C’s standard gun armament with the AGS 250.A electro-thermal chemical gun purchased from Kriegzimmer. The ETC weapon, the only one of its type in Coorsota, provided invaluable insight into armament design and led Allis-Chalmers to begin developing its own ETC-style weapon. Unfortunately progress on the design stalled as Allis-Chalmers realized it didn't have the technical background or experience required to produce efficient models of ETC-style armaments. The project was put on hold as a potential future upgrade for the Lariat MBT and all progress was instead turned to a conventional smoothbore main gun. Eventually the 120mm G120EGS1 high-pressure breech smoothbore gun was developed, and fielded. The G120EGS1 in its base format for the Lariat 1A1 is 55 calibers in length; compared to the original Lariat’s L/45 main gun, and allows for additional gains in terms of accuracy and round velocity. The gun, when fired, operates on a long-recoil principle reducing the total felt recoil energy on the tank. The entire turret is electrically rotated, resulting in reduced heat and a reduction in volume from hydraulic systems. As will be mentioned later, manual turret traverse and gun elevation are available.
Ammunition
The primary ammunition for the G120EGS1 main gun is the domestically produced Type 19A armored piercing fin stabilized discarding sabot and Type 08D high explosive anti-tank multi-purpose round. Additional types of ammunition are available and can be stored. The Type 19A APFSDS anti-tank round is the standard kinetic energy projectile of the Ground Defense Force and fires a rippled depleted uranium projectile weighing 10.0 kg (penetrator weighs only 5.1 kg) from the barrel at a velocity of about 1,650 m/s (using the standard G120EGS1 barrel). The rippled designed lessens drag, allows for some flex in the design (with a ‘softer’ metal at the thinnest portions bonded by a polymer sandwich), and reduces the effectiveness of certain ERA types. Due to advances in propellant design, and using the extended barrel, the Type 19A can reach out to almost 4,000m. The Type 19A’s HEAT-MP counterpart, the Type 08D fires an 11.5 kg projectile at about 1,400 m/s to achieve an effective range of almost 4,500 m. The Type 08D’s warhead is sub-caliber with a discarding sabot and fragmenting outer jacket and is also capable of multiple fuzing options, including airburst. An additional ammunition option is the M40A1 barrel-fired anti-tank guided missile. The M40A1 is designed to be fired from the Lariat MBT’s main gun and utilizes a semi-active laser homing system. The missile is guided by laser – provided by either the tank or another platform (another tank, helicopter, UAV) and is capable of multiple engagement options. The top-attack option allows the tandem-warhead missile to angle up before descending on its target and during its terminal phase the guidance portion of the warhead (used to detect the laser radiation) is ejected off towards the target. This is designed to trigger an opponent’s active defense system, if equipped, and allow the twin warheads to strike the vulnerable upper armor of the tank. It’s effective range is about 12 km.
Autoloader
The Lariat 1A1 uses an entirely new autoloader design compared to the previous S120GAL0 bustle-type linear ramming-action autoloader. In its place is the S121GAL1, or Sigleuir 1VXB by trade-name, drop-shelf type bustle linear ramming-action autoloader. The S121GAL1, sometimes affectionately referred to as ‘Panzervergewaltigen Faustladevorrichtung’, is a fast action bustle-based 42 round ramming action autoloader.
The 1VXB Autoloader was engineered at the Sigleuir Prototyping and Experimental Design Division Facility as a fast action, high reliability, and relatively inexpensive autoloader design contracted by Coorsota's Ground Defense Forces for the M8 Lariat 1A1 MBT. It is a 120mm autoloader design based off the IPR-201's Drop-Shelf Type Bustle Linear Ramming-Action Autoloader, but optimized for the production budget of the Republic of Coorsota's M8 Lariat 1A1 MBT. In 9 days, a working prototype design was tested in a mockup turret rig, consisting of a turret ring stand with an electrical power supply adapted to it, a turret with many internal similarities to the M8 Lariat 1A1 MBT, and with a supplies of simulated shells that would be then loaded into the breech that would drop them into a small collection basket. The turret test bed was created to prevent design conflicts between the actual tank and autoloader integrations, often found in many forms of "cut and paste" jobs, where components are "dropped" onto a tank, then "stapled" to it, with minimal care to conflicts that occur from the physical level to the ergonomic level. In the end, very few revisions were made, specifically noting that the autoloader indicator system was integrated to the tank's viewfinders, and the autoloader ammo tracking system had its own LCD added. In addition, the gunner and commander's multifunction displays are integrated with the ammo management end of the autoloader.
When the gunner or commander, with priority to whoever has ammo selection, presses the selected type of round, the autoloader will proceed to start into cycle one (for estimated time of cycles and operations, see below), where the system will proceed to test its components to ensure the proper operation by operating parameters, then proceeds to move the round selected from the six "shelves" to the ramp, which will adjust its height to allow for this, then locks it into place, waiting on the blast door and external ramp. Cycle two is primarily on the process of the ramp extension and ramp tilt. After this the autoloader will proceed to move to cycle three where the round, within its armored box, will be pushed outwards from the bustle toward the first ramp where it locks into place while the round is inserted into the gun; this will then proceed to allow the ramp extension mechanism to release the latching mechanism of the armored box, so that the box can collapse as the rammer proceeds to retract. On cycle four, as the rammer and ramp retract the box is dropped and the gun is unlocked to be prepared for firing, waiting for the ramp to fully retract to prevent collision during recoiling from firing. The autoloader completes these cycles in about 1.8 seconds, with 2 seconds being the longest wait based on the capacitor charge. The capacitor has the capability to operate the rammer up to three times before having to be fully recharged from zero. An addition to the autoloader is the capablity to operate it rapidly in manual mode, where the gunner would be able to operate the autoloader through selecting the cycle one by lever, and then rotating the hand crank system which is linked to a mechanically automatic gearbox which also can be selected to a 1 to 2 fixed gear as a backup. The gunner would then advanced through the cycles in 6 seconds, going from cycle one to two and then having the ramp and rammer starting to retract in cycles three to four. This system allows for fast, efficient loading operation. The ammo selection is handled, however, by using a second hidden panel, which is opened, where L1-3 and R1-3 is marked, with a lever pointing to each letter-number combination indicating the shelf selected. A rotating hand crank is then used on that side to push the round in, causing the rotating indicator to go from the red to the green on the cycle crank.
The autoloading system can be loaded from internally in the tank, where the round is inserted through the same blast door in its armored container, and then the autoloader will automatically read the round type by the indentations on the shell rim. The autoloader will then proceed to raise the ramp to the right level and insert it to the proper shelf. The manual operation can be done as well through using the selection crank, and sliding the bottom switch from "Load Gun" to "Load Autoloader", and then rotating the hand crank to move the ramp into the proper shelf height and moving the round into the shelf before locking the internal blast door and ramp into the normal position again; the same green-red indicator used on the manual operation of the autoloader is used to confirm if the cycle is completed. External loading is completed by unlocking the external hatch from the inside, then pulling it outwards from the rear center of the bustle. After this, an internal hatch will be revealed, which can be pulled open by grasping the handle and pulling upwards, which will reveal the inside of the autoloader ramp from the top. Rounds are inserted from the rear, within their armored boxes to load to the autoloader, the same manual process can be completed or the automatic process. The ammo management computer can be used to specifically pick which "shelf" the round type will belong to.
The autoloader has full venting paths through the sides, if any form of penetration should happen, combined with the fact of individually armored ammo boxes that prevent ammunition fratricide. The autoloader itself is armored to prevent up to 35mm autocannon penetration, combined with the bustle armor that the tank already has. Combined with internal mounting points for 18 Halon bottles (3 bottles per shelf, which can be manually fired, or automatically fired as separate bottles or as a group), as well as blast door separation. The autoloader has great fire fighting capablity, and if that were to fail, the venting paths also prevent each "shelf" from going up, minimizing ammunition fratricide to a maximum of seven shells per shelf level combustion. Not only does the autoloader have crew separation to ammunition while autoloading, it has its own self contained NBC system with air conditioning to ensure that no matter what form of penetration entering the autoloader, no entry into the fighting compartment can occur.
Each round is within a collapsible box with 1CM thickness on all sides for 150mm diameter (shell diameter, not actual round diameter) by 1,000mm long rounds. With complete immunity to small arms fire and extreme resistance to .50 anti IFV/APC and anti-air fire, followed by moderate resistance to 25mm AP-I or HE-T rounds. The armored box also has venting paths to prevent ignition fratricide, combined with its natural heat resistance shielding the round. The box its self can be collapsed into flattened parts after removing the retaining latches, similar to cardboard boxes; this is combined with the tank's autoloader where it automatically handles the storage of the empty boxes, which can be reused. Autoloader capacity of forty-two rounds determined by: three stacked levels in height (three ‘shelves’), two sides (left and right with center being occupied by ramming system occupying 200mm), and seven rounds per side of each shelf.
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Secondary Armament
In addition to the tank’s main gun, the Lariat MBT carries a coaxial G25AGS2 25mm autocannon and 1500 rounds of ammunition as standard equipment. This was possible after some internal modifications were made, mostly resulting from the use of a new autoloader and other internal features which freed up additional space. The upgraded gunnery allows the tank to better engage IFVs, APCs, and other targets without utilizing its main gun ammunition and which may be out of range of a conventional 14.5mm machine gun.
The commander’s position in the Lariat 1A1 upgrade comes standard with the A141RGS1 Commander’s Remote Weapon Station. The A141RGS1, better known as ‘the Rifleman’ (for the remote weapon stations’ designation’s {A141RGS1} supposed resemblance to Adrian Riggs’ name, a popular Coorsotan film star who played ‘the Rifleman’), is a large multiple-weapon capable remote weapon station that serves not only to give the commander an independent ability to engage targets from within the tank but also serves as his ‘heavy’ independent viewer. It was designed to be an ‘add-on’ feature and not require extensive modification of the turret or interior of the tank. To this end, the Rifleman RWS requires little modification of the Lariat 1A1 turret and most of its components are mounted exterior to the armor. The Rifleman remote weapon station provides all the same electronics system as the TS/EQ-31A Commander’s Independent Viewer only in a larger, more rugged format. This includes the commander’s laser rangefinder/designator, thermal imager, and day/night optics. In this situation, the Rifleman has largely replaced the TS/EQ-31A for the commander’s purposes; however, the TS/EQ-31A is retained as a back-up and to give the gunner an auxiliary imaging system in place of his primary sights and backup systems. Besides this, the A141RGS1 has the ability to mount several types of weapons from the MG4 light machine gun all the way to the G20AGS2 20mm autocannon (requires modification), however the MG5 14.5mm heavy machine gun is mounted as standard fare for the Lariat 1A1 and fulfills its purpose well as an anti-personnel, anti-helicopter, and anti-light vehicle tool. This lethality can be expanded on by adapting the Rifleman RWS with an ATGM launching system. This pack, armored up to light machine gun ammunition, carries two anti-tank (or anti-aircraft provided they are small enough) missiles in a shuttered, ready-to-fire pack, giving the Lariat 1A1 the ability to engage tanks at extended ranges, although the gun-launched ATGM is already capable of this. Light anti-aircraft missiles are also capable of being utilized with this system and are often found useful scattered in deployed Lariat 1A1s, creating a hazardous environment for opposing aerial assets.
An interesting addition to the Rifleman remote weapon station is a portion of the CQ-29 active defense system, particularly, the grenade launcher systems and part of the millimeter wave radar component. Among the benefits of this arrangement: the engagement distance is increased by around a meter, the whole Rifleman RWS can be used as a sort of close-in defense system and not only engaging the threatening warhead/missile but also engaging the launch point of that threat. Ammunition for the remote weapon station, depending on the type of the weapon, is fed from within the tank and can be reloaded from within the tank provided that a new belt is attached before the old belt has left the interior of the tank (often, the crew will link two or more belts immediately to save them from having to do this after firing only ten or fifteen rounds).
The final weapons system is the gunner’s weapon mount which can be fitted to use a light machine gun.
Defense
Armor
The armor scheme of the Lariat Main Battle Tank was developed from materials, ideas, and examples provided by the Advanced Materials Education Coalition (AMEC) of Larange State University and the Knife Point Technical Institute. Allis-Chalmers contacted AMEC in regards to the educational consortium researching and developing advanced materials intended for use in armor of a main battle tank. Larange State University, being a state university, opted not to participate in the research phase but did allow the use of previously researched materials and techniques to be used by the research group from Knife Point. The Knife Point AMEC developed the “Cuera” armor scheme for use in the Lariat MBT and subsequent variants. The Cuera armor system is composed or largely common materials arranged in a specific format which provides a startling amount of protection for the thickness and weight of armor but without inducing exorbitant costs for exotic materials. To this end, the Cuera armor layout is as effective, or more, than most expensive, composites-augmented armors. The Cuera armor scheme is composed of the following layers, beginning with the outermost layer for the turret face and glacis:
Primary Armor (600mm real thickness; Spacing through out the design results in a real thickness between 650-700mm)
• 150mm high hardness monoplate steel
• 20mm rubber plate
• 10mm plastic plate
• 20mm rubber plate
• 100mm section of steel plates of 20mm thickness at 45 degree angle standoff from each other at 20mm with reactive polymer that quickly solidifies from HEAT or pressure
• 50mm depleted uranium
• 50mm hard monoplate steel
• 50mm rubber
• 50mm hard monoplate steel
• 50mm soft monoplate steel
• 10mm hard monoplate steel
• 10mm soft monoplate steel
• 30 mm rubber
The varying thickness and density (either soft or hard) steel plates induces yaw into a penetrating KE projectile, potentially even shattering it. The turret face armor is angled at 30 degrees from the vertical and 12 degrees from the horizontal. Turret side armor is angled at about ten degrees from the vertical.
Following this is the 100mm spall liner, composed of densely packed fibers within a rubber enclosure within a plastic box. The face of this box towards the armor side is 5mm steel and rubber plates for 50mm. In addition, all interior metal surfaces are first covered in a plastic panel then painted with a rubber-like non-slip paint surface.
Armor on the turret sides is effectively similar only slightly reduced thicknesses and reduced spacing. Armor on the back of the turret and hull is reduced by removing the 100mm section of angled steel plates and the 50mm soft/hard monoplate sections (400mm). Roof armor is between 150-250mm real thickness using a similar construction scheme. Most of the exterior armor is coated in a non-slip layer.
To defend against a land mine threat, or a triggered explosive threat, the underside of the hull utilizes a similar version of the tank’s overall armor to help defeat high explosive land mine and other threats. This spaced and heavily layered armor, although thinner and lighter in overall construction, aids considerably in the defense against a large portion of mines and some improvised explosive devices. To augment the armor in defending the crew, the crew’s seating is further armored with titanium layers and an additional spall liner. Placement of non-critical components between the initial armor and hull-underside spall liner provide some additional protection.
Vaquero ERA
The Vaquero ERA system was designed using data from the Advanced Materials Education Coalition, Allis-Chalmers Defense Services Division, and independent labs and entities across Coorsota and abroad. The Lariat MBT’s optional explosive reactive armor was designed to combat most munitions encountered on the battlefield today and originally intended to be equal to most available types of explosive reactive armor. ERA research in Coorsota started with the arrival of the MCA-7C Timber Wolf MBT in order to develop a possible ERA package for the tank. Progress was slow however but produced a working, if basic, ERA system. Allis-Chalmers, with federal aid, funded several additional research and development programs at universities (explosives research) and private labs (ERA design and implementation) to eventually produce the precursor to the Vaquero ERA. With the initialization of the Lariat MBT program, design was halted on fitting the ERA to the MCA-7C and it was instead brought back to the research and development phase with the intent to modify and fit it to the Lariat main battle tank. This project resulted in the Vaquero ERA system. The Vaquero ERA is a layered system composed of the following layers besides an initial ceramic outer layer (to defend against the initial warhead of a tandem-warhead weapon) and a steel/ceramic backing:
• Layer 1: Trigger in very front, plate behind, and explosive below, which alternates for the second plate, inverts again for the third plate, and again for the fourth plate. When a HEAT jet or KE penetrator triggers the ERA, the first layer of that portion of the ERA will detonate and the explosives on the bottom will push the plate up (or roughly perpendicular to the jet/penetrator's line of travel). If the jet/penetrator penetrates that plate, the explosives on the second layer will push the second plate downward and so on. This serves to 'feed' the plate into the jet or penetrator from both top and bottom at different depths of penetration. This'll feed material into a HEAT jet eroding its effectiveness, and depending on the composition of a penetrator (especially the narrow diameter/long rods) potentially snap it or create some yaw, at least before it reaches the final ERA layers.
• Layer 2: This is a thinner rubber-polymer-steel layering which induces yawing in KE projectiles and further impacts a HEAT jet.
• Layer 3: This is the heavy ERA component of the Vaquero ERA system and is designed to specifically eliminate the KE threat by using shaped charges to induce more yawing in addition to dismembering the penetrator. Heavy blast layering behind this is formed in a way so that if triggered, it will likely crush any remnants with its faceplates and explosive pressure.
The entire system is encased in resin.
Countermeasures
The Lariat MBT was originally designed to carry only a basic set of countermeasures, mainly grenade launchers (to launch smoke grenades, aerosol canisters, or chaff) and a smoke generator. However, as development wore on, additional features were researched and available for the initial production model. Allis-Chalmers engineers took the next step and combined all the countermeasures features into a single unit to ensure the survival of the tank against a wide assortment of threats. The basis of the SS/CQ-10A combined active/passive countermeasures system is the smoke generator found near the diesel engine and grenade launchers (8x with 2 canisters per launcher; can fire chaff, aerosol, or smoke). These are capable of operating independently under crew control or with the SS/CQ-10A system. Beyond this is the component CQ-29 mast-deployed active protection system and is designed to combat most missile threats. The CQ-29 is not a single system but is rather both active and passive and utilizes soft-kill measures to assist its core hard-kill system. Threats are located using a passive thermal imager as well as an active radar system, and these can operate with the tank’s primary systems. Using infrared jammers, electronic interference, chaff/smoke/aerosol launchers, smoke generator, or decoys, the CQ-29 will attempt to ‘soft-kill’ the threat, if this is unsuccessful in completely eliminating the threat, the CQ-29 will resort to its hard-kill system. When this determination is made, the CQ-29 will shutter the primary optics (the primary forward looking infrared, RWS, and the commander’s primary thermal imager; leaving backup imagers and optics) and the hard-kill system is activated and fires explosive packets at the incoming target.
The third system is simply a threat warning system designed to allow the crew to rapidly engage an ATGM crew, and if configured to do so, will automatically align the RWS to the ATGM launch point and allow the commander or gunner to engage the target.
Fire Control
The Lariat MBT’s fire control system is composed of a number of systems which operate in unison to provide the crew with an unobstructed battlefield view and maintain their awareness of their surroundings. In addition to the optical periscopes positioned around his egress hatch, the commander is given an independent periscope with an LCD information overlay (TS/PQ-12A) and independent thermal viewer TS/EQ-31A. The two systems provide 360 degree target identification while the thermal viewer is enhanced with a day/night camera for higher-resolution non-thermal imaging and identification as well as a commander’s independent laser rangefinder and designator. Output from the TS/EQ-31A is displayed on a multifunction LCD monitor in a stabilized mount, and can appear on the LCD optronics overlay on the TS/PQ-12A. The TS/EQ-31A’s output can also be transferred to the gunner, allowing the gunner access to the same field of view of the commander (and vice versa).
The gunner’s station is fitted with an FC/TQ-7A1 dual magnification stabilized primary sight. The FC/TQ-7A1 has an integral laser rangefinder and is mated to a Sheyenne Technologies Group OsprEye II forward-looking infrared imager (with a smaller, lower resolution backup imbedded in the turret on the other side of the main gun). The OsprEye II is a new addition with the Lariat 1A1 upgrade and represents a leap in design technology over the original OsprEye forward-looking infrared imager. The new unit features a polarization-sensitive focal plane array with etched polarization elements integrated to each imaging pixel. The OsprEye II allows for greater target detection by exploiting infrared polarization signatures and enhancing the contrast of targets versus backgrounds. In addition, the OsprEye II carries an uncooled indium gallium arsenide (InGaAs) shortwave infrared imager to better defeat optical camouflage and to provide another layer of information for the fire control system to process into a compound image for the gunner/commander. The InGaAs SWIR imager is also capable of seeing most laser rangefinders, specifically those in the eye-safe range. The FC/TQ-7A’s laser rangefinder is a Neodinium Yttrium Aluminum Garnet (Nd:YAG) solid state laser and can provide up to five range values in three seconds. Augmenting this is an electro-optical rangefinder which uses a camera to focus in on its target. To focus, the lenses are moved apart and once the tank is in focus, the range is determined by taking a value associated with the distance the two lenses are apart and using that to derive the range to target in 5m increments. This allows the tank to find the range of an enemy tank while emitting no laser radiation (and tripping a laser warning receiver) and is particularly useful in the first engagement. The range data from both systems is transmitted to the fire control system via fiber optic link and is used to calculate firing algorithms. The gunner, and commander, both have access to the laser rangefinder. The commander’s rangefinder also serves as a laser designator with a variable power setting. Maximum laser range is ~12km.
A laser imaging system, such as LADAR or LIDAR, was originally planned to be fielded in the Lariat main battle tank. However, introduction of a LADAR system would have compromised the tank’s ability to operate passively, as the LADAR system, through its laser imaging system and intermittent laser pulses, would essentially serve as a targeting beacon for enemy tanks with laser receivers/imagers. Instead, the Lariat and Lariat 1A1 are fitted with the ES/WQ-1B Common Warning Receiver. The ES/WQ-1B is composed of several RADAR and laser warning receivers located around the vehicle to provide full awareness. Four imagers are located on the sides of the turret with two looking forward and two looking aft, each covering a 90 degree arc, and are designed as a higher resolution laser warning receiver, capable of lending information to the fire control system to engage targets employing an active LADAR system.
Updated with the Lariat 1A1 upgrade package, the Cortronics CS/TQ-3A is the system that ties all the imaging systems together and produces a fire control solution for the main gun. A composite image of the target is created using the electro-optical and imaging infrared (long wave/thermal and short wave) imaging systems. The composite image provides better target definition with warm and cool spots being directly referenced with the non-thermal images gathered by the SWIR and visual (low light) imaging systems, defeating a large number of optical and thermal camouflage patterns. The CS/TQ-3A directly controls the main gun and provides fire-on-the-move, stabilized operation with high accuracy and efficiency. The system is capable of being locked onto a target to maintain a continuous fire control solution. A queuing system is available to the commander to designate and queue targets for the gunner, allowing up to ten simultaneous targets to be queued and tracked. The system operates using a single hard-drive hard storage system in a shock absorbent casing but actively uses only solid state memory devices during actual operation; this prevents hard maneuvers, hits, and roughness from damaging the tank’s memory. When the tank is shut down, the solid state memory transfers to the hard drive until the vehicle is started. Both forms of memory, solid-state and hard-disk, are capable of being upgraded to any size necessary to carry out all the functions required by the crew and fire control system. Finally, all crewmembers are given at least one multifunction LCD display. All electronics are shock and jolt stabilized.
In addition to the actual imaging and fire control systems, the CS/TQ-3A carries several other features to assist in the tank’s operation. The fire control system of the Lariat 1A1 MBT maintains a standing record of the current lifetime of the barrel and how many rounds have been fired through it. When the breech is opened and the shell has been extracted, a small laser measures the interior barrel diameter and its change from the previous scan. The fire control system then uses this data, in addition to a stored barrel wear spreadsheet (with expected wear values), to compensate the fire control solution for barrel wear. Finally, the fire control system computes and accounts for air temperature, humidity, target velocity/direction, tank velocity/direction, wind velocity (using a cross wind sensor), barrel temperature, muzzle reference system, and other factors in its fire solution. Besides updated bussing systems, computer components, etc. the Lariat 1A1’s CS/TQ-3A includes a new system designed to allow the tank to better engage known threats. Using the tank’s upgraded solid state and hard-storage systems, the Lariat 1A1 now has the ability to store target information, specifically thermal image characteristics and useful information of certain tanks to aid the Lariat 1A1 in the proper identification and best course of action to take when engaging a tank of a certain model. One interesting feature of this functionality is the ability to program the fire control system to aim for specific ‘weaknesses’, whether these be actual physical weaknesses (such as reduced armor, design attributes, etc.) or weaknesses in capability (such as programming the CS/TQ-3A to take advantage of an opponent’s lower-ranged gun, or sensor deficiencies), although in the former case, this depends largely on range due to the circular error of probability of actually hitting a small area on a tank while in motion on the battlefield. This system also maintains a standing catalogue of engagements (storage space and tank survival permitting) including most of the conditions encountered during firing and whether or not the hit was successful on the tank.
The TS/FQ-101A is a fire control subsystem designed to be used in a high-threat environment. In a typical combat situation, if a tank is struck, the chances of that tank recovering from the impact in time to fire a shot to defend itself is relatively low, allowing the opposing tank to load and fire a second round. The advantage often goes to the tank that can fire, and hit, first. A single shot that is not enough to disable the Lariat 1A1 but invariably affects the crew and other systems, creates a few moments of ‘down time’ and gives another enemy tank the chance to quickly follow up and disable the Lariat 1A1 MBT. The TS/FQ-101A levels the playing field, partially negating the opponent’s advantage in firing first. When in a high threat environment, the gunner presses an ‘arming’ button as he’s adjusting the tank’s solution on the target and preparing to fire. In a situation where the Lariat 1A1 can fire first, the gunner will depress the trigger and the weapon will fire. However, if the Lariat 1A1 is struck before it can fire and the impact/damage is enough for the gunner’s hand to leave the control (and if the damage does not seriously affect the core fire control and gun systems), the Lariat 1A1 will automatically engage the target the gunner was locked on to. Once the round is fired, the autoloader will cycle in a new round. By about this time the gunner, unless he is incapacitated, should be able to resume operational control over the main gun and fire control systems. If he is incapacitated, the commander can take control of the main gun.
The gunner and commander of the Lariat 1A1 MBT are each given something considered antiquated to most current tank crew – a completely analog fire control system augmented by a size/range comparison plate with a provision for a secondary laser-rangefinder. A mechanical computer is also provided. The analog fire control systems were added to all in-service MCA-7Cs due to a common criticism of the tanks’ fire control and targeting systems in relation to the sometimes very rough terrain encountered in Coorsota. Most problems occurred during trials or training exercises when the tank in question was on the move and preparing to fire on a target, and hit a rock ledge. The subsequent impact and jolt, although not enough to actually damage the tank, did its number on the sensitive electronics within, often knocking out one or more LCD screens and partially disabling some fire control systems. From this point forward, the tank couldn’t effectively fire its main gun until the tank could be serviced in the field. The experiences led to the shock-dampening of all electronics in the Lariat 1A1 MBT, including all monitors in cased in a shock absorbing cradle. The completely analog fire control system including manual gun elevation and traverse, would allow the tank to effectively operate without power to the turret control systems, when the primary and secondary fire control systems are disabled, or when the tank wishes to remain hidden yet still engage a target.
In addition to the above fire control and electronics, the Lariat 1A1 MBT carries the Cortronics VRC-9661 multiband, multimode tactical vehicular radio which provides HF (2-30 Mhz; long range strategic communications) and V/UHF (30-512 Mhz; short range tactical communications) radio communications ability in addition to digital communications between tanks (such as sharing firing data or coordinates, etc.). The system also provides inter-tank communications between the driver, commander, and gunner. In addition to this, the system’s “field telephone functionality” is diverted to an externally, rear mounted phone system which allows supporting infantry to use the communications system to communicate to the tank’s crew or to communicate with any other unit (from tanks and aircraft to infantry) within range. Finally, the VRC-9661 provides a GPS connection to allow for both satellite communications (if equipped) and geolocating abilities.
Mobility
Introduction
The D990AGP1 is the result of a mid-life engine upgrade program to increase the D900AGP2’s fuel efficiency and power density to an extent, however, the D900AGP3, as it was known at the time, slowly evolved into an entirely new engine: the Sand Draw Diesel (or SANDIESEL) D990AGP1. To this end the previous engine’s common rail fuel injection was replaced with a new common rail system using piezoelectric crystals in place of solenoids in the injectors and provides an instantaneous response for fuel injection. An additional feature was added, as a result of the injection modification, which allows for greater use of available air in the cylinder. The sequential turbochargers were modified with ceramic turbine wheels to provide lower inertia and a faster response time to load. The conventional barrier-filter filtration system was replaced with a pressure-side filtration system with the primary filter downstream of the turbochargers and a pre-filter upstream. And finally, an electromechanical valve train was added to give full control of all engine functions to the Central Electronic Control Unit.
Engine
The D990AGP1 is a liquid cooled multi-fuel capable twelve cylinder (four valves per cylinder) sequential turbocharged four-stroke diesel engine displacing 28L (1708 cubic inches; 150mm x 132mm bore*stroke). The diesel engine is controlled by a Central Electronic Control Unit (CECU) which observes and regulates every major action of the engine including varying turbocharger pressures, valve timing, direct injection properties (injection timing, duration, fuel amount), etc. and can optimize the performance of the engine for several preset modes from which the driver or commander can choose from: the two major modes being performance and efficiency. The engine mode can be switched during any moment of the engine’s operation and crews may ease fuel consumption during transit with the CECU set to efficiency and when preparing for battle, switch to performance. The CECU also provides advanced diagnostics to the crew of the tank during operation as well as to repair personnel when the engine is in need of repair.
The CECU-controlled common rail fuel injection system operates the fuel injectors using piezoelectric crystals. This allows for a more precise control of fuel flow to the engine and permits the fuel flow to be controlled four times more quickly than the previous system. Additionally, the new system incorporates a ‘pilot injection’ feature which, prior to the main injection, releases a small, pilot amount of fuel to initiate the combustion process without the dramatic peak in the heat release rate compared to a conventional fuel injection and ignition process (allows the air in the cylinder to be better utilized). Using less than ten percent of the injection fuel in the pilot injection (determined by the CECU), this system reduces NOx by approximately 35 percent and smoke by 60-80% without worsening, and actually improving, fuel efficiency.
The traditional mechanical valves, cam, rockets, etc. on the D990AGP1 are replaced, entirely, with an electromechanical valve train system (EMVT). With the EMVT system, the traditional poppet valves are operated by electromagnets positioned above the valve guide, effectively doing away with the mechanical cam and rocker system. The valve is operated through two sets of magnets, one above and one below an armature on the valve stem above the cylinder head and within the EMVT housing. For air-intake or expelling exhaust, the lower magnets are electrified and pull the plate downward thus opening the valve. When the valves should be fully sealed for compression and ignition, the upper magnets are electrified, the plate is pulled upwards, and the valve is sealed. Two springs, one above the assembly and the other below, recessed into the cylinder head between the assembly and head, maintain tension and when the engine is off, keep the valve in the half-open position. The system allows for fully variable valve timing (including faster valve-to-seat velocities: below .05 m/s) and superb integration with the advanced direct injection systems already employed by the D990AGP1 engine. The ability for the engine computer to vary the valve timing and duration-of-opening allows for greater fuel efficiency, improves cold-start and warm-up behavior, etc. especially in conjunction with the other features involved in the D990AGP1. Additionally, repair is facilitated due to the easily-replaceable nature of the single EMVT system for each cylinder head and requires no tuning beyond plugging into the CECU.
The pistons are composed of high-strength steel with a symmetrical shallow-bowl head design that works in conjunction with multiple injections of fuel and twin intake valves to boost compression. Higher power densities result from this combination. Air filtration is now provided by a ‘pressure-side’ filtration system which uses a more compact filtration component positioned downstream of the turbochargers with an up-stream vortex tube prefilter. The new filtration system results in less than half the volume of the previous barrier-filter filtration system and less engine gas exchange loss if there’s a blockage in the filter.
The D990AGP1’s turbocharging system operates as a sequential unit with two independent ceramic-wheeled turbochargers working in tandem. The first turbocharger compresses combustion air as usual. Exhaust is directed to a second turbocharger downstream from the first. The energy from this second turbine transfers to the crankshaft and offers multipoint efficiency gains (~3-5%). The new ceramic turbine wheels allow for lower inertia and thus a faster response time to load. The ceramic face now also functions to protect the turbine wheel in the face of particulate matter between the pre-filter and primary filter of the air filtration system.
The crankcase offers structural ribs to increase the crankcase’s life, improve strength, and reduce operating noise. Crankcase oil is now cooled through pipettes to decrease operating temperatures. A grid block/head heater and fuel preheater provide cold weather starting ability in addition to the CECU’s ability to adjust operating conditions. A muffler and combined radiator system are also present.
Together, all of these features allow the D990AGP1 to produce 1230 kW (1650 HP) in addition to a power reserve of 115 kW at 1,800 RPM. The engine also produces a 40% torque rise (from lowest available torque to highest available torque) at 1,400 RPM. Maximum torque is ~4400 Nm. No governor is present beyond the CECU’s moderation. Instead crews are trained to maximize fuel economy when required. This allows the full breadth of the engine’s power and capability to be used when needed. Warning and predictive diagnostic systems are present to alert the crew to dangerous conditions if they proceed to push the powerplant systems too far.
Auxiliary Power Unit
Using experience from adopting the MCA-7C Timber Wolf, Allis-Chalmers designed an under-armor auxiliary power unit for use on the Lariat 1A1 MBT. This 32kW diesel turbine allows for the primary systems of the tank to function without using the main engine and wasting unnecessary amounts of fuel (as well as lay in ambush with a reduced heat signature).
Transmission
The drivetrain is rounded out by a Western Motors designed T250FGT1 transmission component. Originally, the Lariat 1A1 MBT was to be fitted with a similar, automatic transmission. However, in component testing where the transmission was instead used in a converted M-60 MBT, the automatic proved to be troublesome. Proper crew training, however, alleviated the majority of these problems except for the transmission’s capability to serve in a ‘tractor’ role, such as towing other tanks. The Ground Defense Force required that a tank be able to also serve as a recovery unit for other tanks if a dedicated recovery vehicle was not around, and the automatic transmission was ill suited for this task. Instead, Western Motors produced a similar design which uses a series of primary gears, eight in total, and each with its own range of three gears. This completely manual system would allow the driver to select an appropriate gear for the task at hand, and have the capability to upshift or downshift to meet the power requirements of the task. During testing, the transmission when placed in first gear (up to third gear depending on the medium the tanks are operating in) had no problem pulling a similar-weight tank, and the driver could then shift between three ranges in this gear, going from 1-1 (creeper) to 1-2 and then 1-3 (and back again) with the motion of a single lever and no clutch. All gears can be shifted into from a standing point, with the upper four gears requiring little or no load and designed primarily as maneuvering or road gears. Fourth gear was optimized as a ‘battle gear’ and provides quick acceleration with the throttle and smooth gear transitioning. This gear can operate under some load in less-than-ideal terrain (such as in snow or light mud). The modified T250FGT1 provides reduced maintenance over its automatic cousin, improved fuel economy, improved performance in some areas, and the ability to serve as a recovery, or even engineering, vehicle. The T250FGT1 is a compact automatic transmission which features an infinitely variable hydrostatic-hydrodynamic steering system, combined braking system, infinitely variable cooling fan, high efficiency, digital controls for some functions (using a derivative of CECU), and provides easy operation to the driver and repair to maintenance personnel. The transmission is mounted parallel with the engine and entire engine/transmission package is capable of being removed together using a built-in rail assembly facilitating quick replacement or repair in field conditions.
Suspension
The Lariat 1A1 MBT's suspension was designed, like the rest of the tank, for Coorsotan terrain. Thus, its suspension is capable of adapting to Coorsota's widely varied terrain - from rolling plains to the more ubiquitous rocky foothills. The suspension is largely hydraulic with swing arms designed to give the road wheels a generous amount of movement and soften the motions of the tank so the fire control system has an easier time at compensating for the movement. The suspension is also partially active, allowing for the ride height of the tank to be adjusted (such as positioning the suspension to give a greater hull-down capability). Road wheels, track supports, idlers, and drive sprockets are all composed of high strength steel. Road wheels have a layer of rubber to reduce wear to track links and to the wheels themselves.
Miscellaneous
The Lariat 1A1 MBT can serve as an emergency recovery vehicle with no threat of damage to its drive train and thus carries the mounting points and tow hooks required to be able to tow and recover other main battle tanks in lieu of a dedicated recovery vehicle. Heavy duty tow cables and chains are carried in addition to straps for recovering smaller vehicles.
Finally, the Lariat 1A1 maintains the ability to carry external fuel stores. These external fuel stores, however, are not drum-type but instead a box-style system hung over the muffler system on the tank and not directly visible from the forward arc. They are self-sealing and partially armored against most small arms fire and shrapnel. Due to their built-up nature, they are usually recovered later. The fuel boxes can be jettisoned from within the tank. A drum-type external fuel system can also be used.
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