Patria XA AMOS

     Notes: Variously referred to in different sources as the XA-203 AMOS and the XA-200 AMOS, “XA AMOS” seems to be the designation of the vehicle in most sources.  Though in development, the Finns tested the vehicle with an XA-185 base chassis, the current production vehicle uses an XA-203 chassis. This is topped with the Hagglunds/BAE AMOS (Advanced MOrtar System), which consists of a large but low-profile turret housing a pair of long-barreled (barrel length of 2.4 meters) mortars which can fire in the direct-fire mode of conventional indirect fire mode.  Several countries are interested or have already purchased the XA AMOS; the Slovakians have already purchased the XA AMOS, and some other Baltic States and Middle Eastern countries are seriously considering the vehicle.  One surprising future customer is the US Marines, and AAI in the US has already gotten a license to domestically-produce the XA AMOS for that purpose (though there is still some discussion going on about what the base chassis might be, the Marines appear to be interested in the complete XA AMOS vehicle).  It is rumored that the US Army is interested in the AMOS turret system, but wish to mount it on a Stryker chassis.  The Swiss and the Saudis are reportedly trying to decide between the XA AMOS and the CV-90 AMOS. The Estonians will probably be the next country that puts the XA AMOS into service, though some reports have them waiting until the AMV AMOS enters production. The Finnish themselves were originally supposed to have the XA AMOS in service in 2003, but delays meant that LRIP did not start until 2006, and deliveries were not completed until 2010. The turret is essentially the same as mounted on the Swedish CV-90 AMOS vehicle, and rounds are being developed in a joint venture between the Swedish, Finnish, Swiss, and Israelis.

     In Finnish service, the XA AMOS is intended to be replaced by the AMV AMOS, though full replacement may take until as long from now as 2025.  Some other countries are also waiting until the AMV AMOS is in full production.  The AMOS system is also going to be deployed in Sweden on some members of the Combat Boat 2010 series; it was originally to have been deployed on the CB-90 series, but proved to be too heavy and have too much recoil forces for that boat.

     The AMOS system’s mortars are breech-loaded by an automatic loader and can fire a variety of 120mm mortar rounds, some of which were developed specifically for use with the AMOS (though many of these new rounds can also be used with most NATO-compatible 120mm mortars).  The mortar barrels are unusual in that they include fume extractors.  The turret can rotate, like any other turret, a full 360 degrees; it can also fire regardless of angle of rotation.  The AMOS system also includes comprehensive fire control equipment, including a GPS (inertial navigation in prototype phases) coupled to a full computerized mapping system, along with a computer for automatic laying of the mortars (once the vehicle is halted).  The automatic laying computer generated fire coordinates from the GPS and mapping computer along with map coordinates given by higher headquarters, an FDC, or a FIST in a more forward position.  Alternately, the laying system can generate fire coordinates if the position of the enemy is known (such as in a direct lay) or using coordinates from a counterbattery radar site or vehicle.  The AMOS system also has a fire control computer and sights for direct fire. A machinegun is mounted coaxial to the mortars. Night vision equipment is provided for the driver and gunner; the commander can access the gunner’s night vision sights, as well as his sight picture.  He can also use his own set of sights to prepare the vehicle to engage the next target.  The night vision can also be used in direct fire, and for both direct and indirect fire magnified day sights and magnification for the night sights is provided.  The AMOS has many howitzer-type features such as range, the capability of MRSI (Multiple Rounds, Simultaneous Impact), the ability to use RAP rounds and their descendants, DPICM, and the ability to use smart rounds.  For direct fire, sabot rounds have been developed, as well as HEAT AND HEAT-Tandem. The rounds fire semi-combustible cases, with a small ring left to be ejected out of the breech when firing. The Finns and Swedish have in fact developed a who new line of ammunition to feed the AMOS.  The AMOS can also fire more conventional 120mm mortar ammunition, though of course at a reduced range and fire control.

     The XA AMOS’s rear area is largely taken up by ammunition racks and the automatic loading system; the turret is largely taken up by the mortars and the fire control equipment.  This means that the interior is rather cramped for the crew and there is little room for their equipment. The driver is in the front left of the vehicle, with the engine to his rear; the entire cab of the XA-203 appears to be there when viewed from the outside, but the right side of the cab is used for equipment storage and also houses some of the computer equipment. The driver has a large windshield to his front and a smaller one to his side; these are made of bullet-resistant glass and have the same armor value as the sides of the vehicle, and an armored shield with vision slits can be lowered over the front windshield to give it the same AV as the rest of the front of the vehicle. The driver’s overhead hatch has a vision block which can be replaced with a night vision block. The rear roof hatches are deleted (the turret is there instead), and the normal commander’s hatch is replaced with one on the roof of the turret; this hatch is ringed with vision blocks.  The commander does not have a weapon mount. The gunner also has a hatch, but his vision blocks do not include the right side. Crew consists only of the driver, gunner, and commander; the autoloading system generally allows the gunner to run most firing operations, though the commander can also assist if necessary. Firing ports and the associated vision blocks are deleted.  The rear doors are retained, but used largely for loading ammunition.  As the mortars are not dismountable, the XA AMOS does not carry a set of baseplates or bipods; however, manual plotting boards, a set of maps, several calculators, and a minicomputer are carried, along with aiming stakes, for use if the fire control computers are damaged or aren’t otherwise working. Radio communications consist of two long-range, data-capable radios and a medium-range radio.

     The XA AMOS is powered by a Valmet 612 DWIBC turbocharged diesel engine developing 271 horsepower.  This is coupled to an automatic transmission with manual backup.  As with the XA-203, the XA AMOS has a modular power pack which can be replaced with appropriate equipment and personnel in half an hour.  An air conditioning module can be easily fitted.  The XA AMOS also has several access panels and hatches to further ease maintenance.  The XA AMOS has a 6x6 suspension with run-flat tires.  An automatic fire detection and suppression system is provided for the power pack, fuel tanks, turret, ammunition storage, and driver’s compartment.  The crew is also protected by an NBC overpressure system with a collective NBC backup.  On each side of the turret are five smoke grenade launchers.

     Twilight 2000 Story: This vehicle does not exist in the Twilight 2000 timeline.

*Floor armor is 4; roof armor is 3.

**Fire Control and Stabilization modifications apply only to direct fire from the mortars or the coaxial machinegun.

Patria XA-361

     Notes: As with the XA AMOS, this vehicle is referred to in various sources by several designations, including XA-360 AMOS and XA AMV AMOS.  I have used what seems to be the most common designation here.  Using the same base concept as the XA AMOS, the AMV AMOS is an XA-360 AMOS chassis topped with the Hagglunds/BAE AMOS (Advanced MOrtar System) turret, with its twin 120mm long-barreled breechloading mortars.  Though orders for the XA-361 were placed by Finland as early as 2003, delays in the AMV program meant that deliveries under LRIP did not begin until 2008, and full-scale production has only just begun late in 2010.  Other countries who have ordered the XA-361 or a variant include Slovenia (who ordered a single-barreled variant in the same turret known as the NEMO system), South Africa, Croatia (who also ordered the NEMO variant), and Macedonia (likewise).  These customers have either not received their XA-361s or variants yet or have received only a few as of late November 2011.  Possible future customers include the UAE and Sweden (who designed the AMOS turret and already use it on a CV-90 chassis).  The XA-361 is also being tested by the US Marines alongside the XA AMOS for a possible future role in the US Marines; one of them will probably be chosen, with production of the chosen vehicle under license by Lockheed Martin in the US and (according to current plans) first vehicle delivery in 2015.

     The XA-361 uses the same AMOS turret as the XA AMOS, and readers can refer to the XA AMOS above for most of the details on the turret, mortar autoloading system, and ancillary equipment such as radios, computers, and backup manual equipment.  The night vision suite is improved somewhat, especially in the case of the commander, who has his own night vision devices.  The primary improvement of having the AMOS turret on an AMV chassis is to take advantage of the greater protection, engine power, and abilities of the AMV.  The base chassis is modified somewhat in the XA-361: the roof hatches are deleted, as is the RWS.  The driver remains in the same place as in the XA-360, in the front left with three wide-angle vision blocks to his front (and to an extent, they also partially give him vision to the left side.  The driver’s hatch has a port into which a night vision block can be inserted.  Instead of the commander being to his right, the former commander’s place is used for equipment storage and some ammunition storage.  As with the XA AMOS, the commander and gunner are in the turret. The crew is protected by an NBC overpressure system with a collective NBC backup, and a fire detection and suppression system for the power pack, driver’s compartment, turret and mortars, ammunition storage, and the fuel tanks.  On each side of the turret are five smoke grenade launchers.  The ammunition is loaded through the rear door, which also has a vision block; in addition, a camera in the rear allows the commander to monitor ammunition loading and replenishment using an LCD screen mounted at his station.  The driver also has an LCD screen at his station, used for navigation and to monitor the state of his vehicle.  The XA-361 AMOS has a GPS and mapping computer module.

     As with the XA-360, the XA-361 is powered by a Scania DI-12 543-horsepower turbocharged diesel, coupled to an automatic transmission.  The driver has conventional controls. The suspension is 8x8, switchable to 8x4 for road use (with the rear set of wheels being the drive wheels in this case). The rear four wheels steer independently from the front four wheels to tighten the turning radius.  As with the XA-360, the XA-361’s hull can take MEXAS appliqué armor as well as be fitted with lugs for ERA (though no country has yet ordered MEXAS kits for the XA-361, and it is not covered below).  There is no MEXAS kit for the turret, though it too can be equipped with ERA on the turret sides, turret rear, and the front third of the turret roof (there is not enough roof on the turret front to mount ERA).  Unlike the XA AMOS, the XA-361’s commander’s station is equipped with a pintle mount, with the weapon mounted depending upon the customer.

     Patria is also selling their AMV/XA-361 with a single-barreled version of the AMOS, called the NEMO (NEw MOrtar).  It uses the same mortar/cannon as the AMOS, and has all the capabilities of that system except for rate of fire, which is half that of the AMOS (8 rounds per minute vs 4 rounds per minute).  Nonetheless, like the AMOS, it is capable of MRSI fire, though an AMOS’s MRSI fire mission would be six rounds, while a NEMO’s MRSI mission would five rounds. The NEMO turret is different from the AMOS turret; it is a partially casemate turret instead of being a full turret. This, in addition to the single barrel, makes the NRMO-equipped AMV much lighter, but just as protected as the AMOS-equipped vehicle.  It’s hull can use the same applique as the AMOS AMV and the turret can also be equipped with a thin layer of applique. The chassis is essentially the same as that of the AMOS AMV, but internally, it is much different, being equipped with an autoloader and the associated machinery, and a different layout of ammunition racks. The automotive components of the NEMO AMV are identical to that of the AMOS AMV, except that the NEMO carries more armor protection on the hull floor, turret roof, and hull roof, relative to it’s normal protection.  It is capable of direct as well as indirect fire, though like the AMOS, it carries only a few antiarmor rounds for self-defense (normally HEAT, though APFSDS rounds are available). The NEMO AMV is light enough to be amphibious, propelled in the water by two propellers at the rear.

     Patria has received only one order for their NEMO/XA-361 combination, from Slovenia. The UAR Navy bought 12 turrets to equip their patrol boats, and Saudi Arabia bought 36 turrets to equip its LAV IIs.  Recently, Patria has offered the NEMO on an armored version of a standard shipping container for those desiring point defense weapons or fixed artillery, with appropriate accouterments inside, and hydraulic legs to stabilize the container.  (None of these have been sold so far.) The turret of the NEMO is 2.95 tons less in weight than an AMOS turret, weighing 1.8 tons without applique. Since the NEMO and NEMO Navy are essentially the same systems, land and waterborne NEMO units are able to seamlessly share information and easily coordinate their fires.

     Twilight 2000 Notes: The XA-361 does not exist in the Twilight 2000 timeline.

*Roof armor for this version is 5Sp; Floor armor is 8Sp.

**Roof armor for this version is 5Sp; Floor armor is 10Sp.

***Fire Control and Stabilization modifications apply only to direct fire from the mortars or the coaxial machinegun.