BSCh-12

BSCh-12
The BSCh-12 in three color schemes, including its appearance at the 2021 Victory Day parade.
Type	Infantry fighting vehicle
Place of origin	Menghe
Service history
In service	2021-present
Used by	Menghe
Production history
Designer	Samsan Defense
Designed	2011-2020
Produced	2020-present
Specifications (BSCh-12G)
Weight	19.4 tonnes (base) 23.5 tonnes (with skirts)
Length	6.88 m
length	6.83 m
Width	3.30 m (with skirts)
Height	3.03 m to turret roof
Crew	3
Passengers	10
Armor	Welded aluminium and steel strike plates with ERA applique skirts
Main armament	Type 110 35mm autocannon
Secondary armament	7.5mm GCh-77 co-axial MG 30mm JSB-30 grenade launcher on RWS 2 × YDCh-72 ATGM
Engine	Samsan SG10Ŭ8G, 10-cylinder flat water-cooled multifuel diesel 550 hp
Power/weight	23.4 hp/ton (with skirts)
Suspension	torsion bar with shock absorbers on 1st, 2nd, and 6th roadwheel pairs
Ground clearance	455mm
Operational range	600 km (road)
Speed	70 km/h (road) 11 km/h (swimming)

The BSCh-12 is a type of amphibious infantry fighting vehicle developed in Menghe for the Menghean Marine Infantry. It is the newly-introduced successor to the BSCh-6, with a heavier armament, better protection, and improved troop carrying capacity. It is the first postwar armored fighting vehicle to be developed exclusively for Menghe's Marine Infantry, in contrast to earlier vehicles, which were developed for both the Army and the Marines.

Development

From the 1980s up to the late 2010s, the main amphibious APC of the Menghean Marine Infantry was the BSCh-6, a light tracked vehicle developed during the late years of the Democratic People's Republic of Menghe. The BSCh-6 introduced a number of features carried forward to the BSCh-12, including a rear-engine layout to improve balance at sea and three side-by-side seats in the front. Beyond these basic features, however, the BSCh-6 still had a number of drawbacks. First, its seakeeping performance was worse than expected, in part because of its low freeboard forward and aft. Second, it had poor armor protection: it could only withstand 12.7mm fire over the frontal arc and rifle-caliber fire from all around. Even the frontal protection was inadequate against Sieuxerrian 13.2mm and Maverican 14.5mm armor-piercing rounds. Third, its armament was very poor. Early versions of the BSCh-6 were armed with three 7.5mm machine guns in firing ports, one of them on the exit hatch. Later versions introduced 12.7mm HMG turrets and 30mm grenade launcher turrets, but in both cases the turret was operated by the squad sergeant rather than a dedicated gunner, a fourth problem.

The Menghean Marine Infantry generally tolerated these problems in the 1990s, 2000s, and early 2010s, treating the BSCh-6 mainly as an armored taxi to the shore rather than a well-rounded fighting vehicle. Amphibious operations during the Innominadan Crisis, however, brought the problems with the type into full view. Menghe's amphibious operations were ultimately successful, but they highlighted problems with the type and intensified demand for a replacement.

By the end of 2014, when the Marines' demand for a new vehicle intensified, several of Menghe's private and public design bureaus had already started work on new amphibious fighting vehicles. Samsan Defense had already built a working prototype SCh.507, an amphibious IFV with a Type 110 35mm autocannon in a manned turret. The SCh.507 carried eight dismounts and three crew, like the BSCh-8 IFV, but it was also fully amphibious due to its low-profile aluminium hull. In conjunction with representatives from the Marine Infantry, Samsan Defense developed a new derivative, SCh-511. This version used an unmanned turret, initially armed with a 30mm autocannon. The remote armament was later upgraded to a 35/50mm autocannon in an exposed remote turret, which was then replaced by the enclosed turret on the production model.

These changes drew a great deal of skepticism from the Menghean Ministry of National Defense. Procurement staff with prior experience in the Menghean Army were wary of the drawbacks of a remote weapon station, and expressed concern that the crew would have no way of manually traversing the turret if the power controls failed or manually clearing the gun if it jammed. The Marine Infantry, however, were impressed with the space savings from the new design: despite having a much heavier armament than the BSCh-6, and fitting inside the same deck parking footprint, it could carry three permanent crew and ten dismounts.

The BSCh-12 was accepted for service in late 2020, with mass-production beginning early the next year. The vehicle was first revealed to the public at the Victory Day Parade on July 27th, 2021.

Design

Layout and construction

The basic internal layout of the BSCh-12 is very similar to that of the BSCh-6. The engine is located in the rear of the hull, providing a counterweight to the heavier armor in the front. The dismounts sit forward of the engine, though in the BSCh-12 they face inward rather than outward and all ten are lined up in two rows. The three crew members sit side-by-side in the front of the hull, with the gunner on the right, the driver in the center, and the commander on the left. This layout is only possible due to the adoption of a remote turret, which sits on top of the hull compartment instead of penetrating into it. The gunner relies entirely on the remote gunsight from the turret, while the commander has forward and forward-right-facing periscopes in addition to a video feed from the visual and IR spectrum sight on the remote weapon station atop the turret.

As on the BSCh-6, the rear-engine layout means that the crew must climb over the engine in order to disembark. The BSCh-12 complicates this process even further by extending the roof armor all the way to the rear of the hull, creating two narrow "passageways" over the engine with the air conditioning plate in between. To disembark, the rear two passengers lift open the two 2.4-meter-long roof hatches, climb over the engine cover panel to the rear, then open the rear doors and release the rear steps. The long roof hatches, 15mm thick and 81cm high, offer side protection against shrapnel and small-arms fire during disembarking, and their front edges nearly line up with the turret, which blocks small-arms fire from the front. Overall, the "trench" created by the raised hatches, recessed walkways, and turret is 1.35 meters deep, allowing a hunched-over soldier to run over the engine and drop down behind the vehicle without exposing his head to enemy fire.

In order to save weight while maintaining a high level of protection, the hull of the BSCh-12 is made from aluminium rather than steel. For further weight reduction, the designers used partial monocoque construction, with the aluminium plates themselves forming the structural supports for the hull. During the design process, however, the increasing mass of the turret made a full monocoque build impossible. Instead, aluminium supports were added inside the hull to support the turret from below.

Protection

4-view of the BSCh-12 (factory model, without armor and added armament) with a cutaway view showing the interior layout.

Official Menghean sources claim that the baseline variant of the BSCh-12 is protected against 30mm armor-piercing shells from a range of 200 meters over the 40-degree frontal arc. It achieves this protection with a combination of thick aluminium armor, sloping, and spaced plating. The upper glacis plate, which comprises 20% of the height of the hull, is 18mm thick and sloped at 82 degrees from vertical, for an effective thickness of 129 millimeters. It is also lined with external reinforcing bars at 15-millimeter intervals; an incoming projectile strikes these before impacting the sloped armor itself. The center front plate is 70 millimeters thick, angled at 30 degrees from vertical, and it also has the 10mm hardened steel water vane in front of it. The lower glacis plate is 50mm thick and angled 60 degrees from vertical with a 10mm hardened steel dozer blade in front. Furthermore, the thick double bottom of the hull is directly behind this plate, so penetrating munitions on its lower edge will not strike the interior of the vehicle. All of these plates are sufficient to stop 30mm APFSDS ammunition from Maverican 2A42 and 2A72 autocannons, given their angle, armor efficiency, and spacing.

Behind the front armor is the vehicle's main fuel tank. The fuel tank is fully self-sealing, and as it empties, a separate valve releases non-flammable gas into the empty space above the fuel surface. When the fuel tank is full, it serves as additional protection for the hull, catching spall fragments and even penetrating projectiles before they can impact the crew and passengers.

The hull side armor is thinner, measuring 43mm on the hull sponsons and lower hull sides. By itself, this is sufficient to stop 30mm and 25mm autocannon fire at an angle of 20 degrees from the vehicle's centerline, but this only results in a 40-degree forward protected arc. At the same 200-meter range, the side armor can withstand 23mm armor-piercing ammunition at angles of up to 30 degrees from the vehicle's centerline. The side and rear armor can also withstand rifle-caliber (7.62×54mmR or 7.5×54mm) armor-piercing ammunition from all ranges, and it offers good protection against shrapnel.

The turret armor is significantly weaker than the armor on the hull. While armor thickness data are not available, Menghean sources claim that the turret can withstand 14.5×114mm fire from the 40-degree frontal arc and 13.2×96mm fire from the 60-degree frontal arc, both from a range of 200 meters, and rifle-caliber armor-piercing ammunition all around. Autocannon ammunition of 23mm caliber or higher, however, will penetrate it at most combat ranges. Menghean designers judged this shortfall to be acceptable given the unmanned design of the turret, which ensures that no crew would be killed in the event of a penetration. Furthermore, because the turret is mounted atop the hull roof, the ammunition is fully isolated from the crew compartment and an ammunition cookoff will not injure the crew.

The hull floor armor is 10mm thick and mostly flat, with no V-shaped design to deflect mine blasts. The front section of the hull has a reinforced and spaced double bottom to protect the three forward crew from mine blasts, but this only extends 1.1 meters into the hull before tapering off. The crew and passengers do have cushioned seats which attach to the hull sides rather than the hull floor, offering some shock protection. Overall, the BSCh-12's mine protection reflects a primary emphasis on conventional anti-tank mines with small blasting charges rather than high-yield improvised explosive devices and roadside bombs.

Armor upgrades

There are several applique armor kits which improve the BSCh-12's protection even further. The simplest adds thin hardened steel plates over the hull sponsons and upper tread return paths. Though less than 10mm thick, these plates can defeat 12.7mm and 13.2mm saboted light armor penetrators with simple tungsten APDS projectiles by fracturing the penetrator before it strikes the hull. Capped 14.5×114mm armor-piercing rounds are still able to penetrate the side armor at angles of less than 30 degrees off-normal. This thin armor plate scheme appeared during prototype testing, but it was apparently not accepted for service.

A more advanced armor scheme, unveiled with the first batch of vehicles at the 2021 Victory Day parade, consists of large reactive armour blocks mounted on top of the aforementioned hard steel strike plates. The total mass of the applique armor is slightly over 4 tons, but because the reactive armor blocks are filled with a combination of foam and air, they are net buoyant and do not reduce the vehicle's amphibious capability. Official sources claim that a BSCh-12 with full applique armor is able to defeat 14.5×114mm armor-piercing ammunition from all ranges and angles, 30mm APFSDS ammunition from 30 degrees off-center, and 23mm AP ammunition from 60 degrees off-center, as well as high-explosive anti-tank ammunition from man-portable rocket launchers.

Curiously, test versions of the BSCh-12 revealed to the public at the 2021 Victory Day parade did not feature the Jŏgran-un active protection system. It is not known whether Jŏgran-un compatibility is planned for later variants.

Armament

A blueprint showing the Type 110 35mm autocannon in its "N" variant, as well as several turrets developed for the weapon. The turret used on the BSCh-12 is on the bottom left.

The main armament of the BSCh-12 is the Type 110 35mm autocannon. In its baseline variant, this weapon is chambered in 35×228mm ammunition. However, by swapping out the barrel and a few other small parts - an upgrade which can be performed in a front-line workshop or divisional arsenal - it is possible to re-chamber the weapon to fire special 50×330mm ammunition sized to the outer dimensions of the 35×228mm cartridge. This upgrade does not affect the ammunition feed mechanism, the number of stored rounds, or even the rate of fire, and it greatly increases the autocannon's armor penetration effectiveness.

The autocannon on the BSCh-12 uses the linkless feed mechanism developed in 2014. Ammunition is fed from two 38-round boxes, one on each side of the gun. Usually, one box is loaded with APFSDS ammunition and the other is loaded with either impact-fused or smart-fused high-explosive ammunition. These boxes are fixed to the receiver and feed through the trunnions, and they rotate with the autocannon as it elevates to keep the feed aligned with the receiver. With the aligned linkless feed system, the Type 110 autocannon can fire at 200 rounds per minute, compared with 90 rounds per minute on turntable-fed Type 110 autocannon mounts. A reserve ammunition storage box forward of the main feed boxes stores 120 rounds of ammunition, bringing total 35mm ammunition capacity to 196 rounds. This unified forward linkless feed box can store a mix of APFSDS and HE or Smart HE rounds. In restocking mode, the gun lowers to a fixed angle of 0 degrees and an automated ramming system transfers rounds from the reserve feed boxes to the ready feed boxes at a rate of 90 rounds per minute, enough to fully restock both boxes in 51 seconds.

Based on international penetration charts for 35×228mm APFSDS, the BSCh-12's main armament can penetrate a 70mm RHA plate sloped at 60 degrees from 100 meters, or a 55mm RHA plate sloped at 60 degrees from 2,000 meters. These are equivalent to line-of-sight penetration distances of 140 and 110 millimeters respectively, sufficient to defeat the frontal armor of most existing IFVs at typical combat ranges. The upgrade to 50×330mm ammunition would be implemented if an enemy country introduced an IFV protected against 35mm APFSDS ammunition over the frontal arc.

Smart-fused 35mm high-explosive ammunition can be programmed to detonate at a specific range from the vehicle, making it useful for attacking infantry in trenches, behind windows, or lying down in the open. It is also very effective against light helicopters and small drones, functioning like a variable-time flak shell. Notably, the smart-fused high-explosive shell for the BSCh-12 is different from the smart-fused anti-aircraft shell for the DGP-35-2, which detonates in front of the target and releases 152 submunitions in a shotgun-like pattern. The BSCh-12 can be loaded with smart-fused anti-aircraft ammunition and has the necessary equipment to arm it correctly, but because there are only two feed boxes, this ammunition type is not typically loaded. Due to their elite status, Marine Infantry units with the BSCh-12 would likely receive full loads of smart-fused HE ammunition, but as the war progresses and smart-fused ammunition stocks are depleted, they can also be loaded with simple impact-fused HE cartridges.

The tall design of the turret allows the autocannon to elevate to +80 degrees, allowing the BSCh-12 to effectively engage drones, helicopters, and low-flying aircraft. Although it lacks a search or tracking radar, the optical sight and laser rangefinder can calculate a firing solution on a moving airborne target, and the airbursting HE shells improve hit probability. Maximum depression is -12 degrees, allowing the BSCh-12 to sweep nearby ditches and trenches with co-axial machine-gun fire or fire from a hull-down position from behind a hill. The turret is stabilized in both traverse and elevation, and can even hit targets accurately while the vehicle is swimming to shore.

In addition to the autocannon, the gunner controls a co-axial machine gun mounted above the autocannon. The ammunition feed box is below and in front of the rear of the receiver, and the box contains 2,000 rounds of ready ammunition.

On the left rear of the turret roof is a modular remote weapon system mounting point. This can support either a 7.5×54mm GCh-96 machine gun with a 500-round belt or a 30mm automatic grenade launcher with a 29-round belt. In either case, the RWS is operated by the commander and its visual-spectrum and IR-spectrum sights also serve as the commander's sights. Heavier RWS options, such as a 12.7mm heavy machine gun, are apparently not supported. Once the RWS's ammunition is exhausted, it can only be reloaded from outside the vehicle, usually by one of the passengers through the open roof hatches.

To deal with armored targets too heavy for 35mm APFSDS, service variants of the BSCh-12 carry two YDCh-72 anti-tank guided missiles. The YDCh-72 is a non-line-of-sight weapon: the gunner pilots it remotely using an infrared video feed from the missile's nose camera, transmitted back to the vehicle by a trailing fiber-optic cable, until the missile acquires a target, at which point the gunner approves the lock and the missile autonomously homes in with a top-attack trajectory. This allows the BSCh-12 to engage armored threats without exposing itself to the enemy's line of sight, unlike an IFV with a SACLOS beam-riding missile, which must expose itself and remain stationary until the missile hits.

Unlike its predecessor, the BSCh-12 possesses neither firing ports for assault rifles nor ball mounts for forward-firing machine guns. Even if it did, they would be covered by the applique side armor plates. The Menghean Marine Infantry concluded that the improved turret more than compensates for the loss of firing ports, especially since the BSCh-6's firing ports were only able to deliver inaccurate suppressive fire at short ranges.

Mobility

The BSCh-12 is powered by a 550-horsepower, 10-cylinder flat engine (technically a wide-angle V engine) which measures just 63 centimeters in height. This arrangement was chosen in order to increase the space over the engine for the dismounts to travel. The engine is relatively easy to maintain: the roof and rear hatches are opened and the thin reinforced sheet metal panels over the engine are removed. If the separate armor section between the hatches is unbolted and removed as well, the entire engine and transmission unit can be lifted out of the hull with the help of a crane.

The engine provides a power-to-mass ratio of 23.4 horsepower per tonne with side skirts mounted, or 28.3 horsepower per tonne without applique armor. Even the former figure is relatively high for an infantry fighting vehicle, giving the BSCh-12 good offroad mobility and acceleration. The vehicle has a maximum road speed of 70 kilometers per hour, and can maintain speeds of 40-50 kilometers per hour on "typical flat offroad terrain." In the event that the vehicle does become stuck in the mud or on an obstacle, the passengers can dismount and attach a log stored on the left hull sponson to the treads, using this to recover the vehicle.

The engine can also drive two internal waterjets, one on each side. These take in water from under the vehicle and expel it just inboard of the toothed drive sprockets. This allows a top swimming speed of 10 kilometers per hour in forward mode, or 2.5 kilometers per hour when swimming in reverse. Steering with the water jets is identical to steering with the tracks; in fact, each waterjet takes power from that side's drive shaft to the drive sprocket. If the waterjets are disabled, the vehicle can still swim at 4 km/h using the motion of its tracks alone.

To prepare the vehicle for swimming, the driver must extend the trim vane at the front, raise the filtered snorkel on the left side, activate the bilge pump, and close the louvered shutters over the engine cooling intake. This entire process can be completed from inside the vehicle. For maximum seaworthiness, the crew can extend the snorkel to double its normal height with an additional segment, brace it with guy wires, and cover the edges of all hatches in a waterproofing paste. This configuration would be used for long-distance ship-to-shore operations, or for landings in rough seas, but it is not necessary for short-distance ship-to-shore operations.

Unsurprisingly for a dedicated Marine vehicle, the BSCh-12 has relatively good seakeeping. It is able to operate safely in conditions of up to sea state 3, that is, with waves of up to 1.25 meters in height. It can also swim continously for up to 10 hours, which in theory is long enough to travel 100 kilometers under ideal conditions. In practical terms, this is more than enough endurance for a formation of BSCh-12s to swim the 30-kilometer distance from the Innominadan mainland to Isla Diamante with a safe overhead margin for engine problems and enough fuel left over to continue fighting on the beachhead.

Amenities

Internally, the BSCh-12 is moderately spacious, giving 0.63 cubic meters of body space to each passenger. This includes 55 centimeters of width for each seat, more than most previous Menghean IFVs and APCs. The increase was intended to compensate for the fact that body armor and heavy webbing are now standard among Marine Infantry units, while also making long amphibious transits more comfortable. The roof is 1.28 meters high, allowing Menghean male youths of up to 95th percentile to sit upright comfortably.

To further reduce clutter in the passenger compartment, the space in the hull sponsons over the tracks can be used to store ammunition, rations, disposable anti-tank launchers, and other supplies behind elastic netting. This space is not included in the figure for passenger compartment volume. Normally, the passages over the engine are left empty, though they are immediately accessible from the crew compartment with no barrier in between. On long road marches, additional supplies may be stored on one side, leaving the other open for the passengers to exit.

It is also possible to place a wounded patient on a stretcher in either over-engine compartment. The patient's head and shoulders extend into the crew compartment, but if the patient is one of the vehicle's own squad members, then at least one interior seat will be empty. As with reserve supply storage, the one-patient configuration still leaves space for the dismounts to exit through the other passage. Alternatively, if the dismounting squad has suffered high casualties and the vehicle is not expected to enter combat before reaching a medical collection point, both over-engine compartments can be loaded with stretchers while leaving four open seats in the passenger compartment. For maximum casualty transport, two more stretchers can be laid on top of the passenger benches, and two more can be laid on the floor, for a total capacity of six patients and two sitting medical aides. This configuration can be used to ferry casualties back to a landing ship offshore.

The BSCh-12 is equipped with an internal climate control system consisting of an air conditioner and dehumidifier. The air conditioner can cool the interior of the vehicle to 25 degrees in external ambient temperatures of up to 50 degrees, and can run continuously for up to 10 hours. It blows cool air through 13 individual adjustable nozzles, one pointing at the face of every crew member, and also cools the onboard electronics units. Considering that the Menghean Marine Infantry expect to operate mainly within the tropics, these features are important for improving crew comfort and fighting efficiency.

Squad tactics

The 3+10 seating capacity of the BSCh-12 brought about a change in squad dismount doctrine. Previously, with BSCh-6-equipped units, the squad sergeant either remained on board as the gunner, leaving the squad isolated, or dismounted to fight, leaving the vehicle unarmed. The BSCh-12's increased capacity allowed a change in squad structure. Now, the sergeant doubles as vehicle commander and remains onboard while the squad dismounts. The tenth seat in the passenger compartment is instead occupied by a member of the platoon HQ: either the platoon lieutenant, the platoon staff sergeant, or the platoon medic.

In battle, the platoon staff sergeant dismounts to direct the infantry from the open and the platoon medic dismounts to support them. The platoon lieutenant remains on board to command the platoon using the commander's video feed. Nine remaining squad members dismount from each vehicle, with the sergeant commanding them from inside the vehicle. The new Menghean Marine Infantry squad is structured as follows:

• Sergeant (mounted)
• Squad marksman (SS-110 designated marksman rifle)
• First fireteam
  • Fireteam leader (H35 assault rifle)
  • Rifleman with AT launcher
  • Rifleman with under-barrel grenade launcher
  • Light machine gun operator
• Second fireteam
  • Fireteam leader (H35 assault rifle)
  • Rifleman with AT launcher
  • Rifleman with under-barrel grenade launcher
  • Light machine gun operator

Variants

Currently, there is only one production variant of the BSCh-12, and it is produced under the designation BSCh-12G. This variant is fitted with side skirts and ERA blocks, two external YDCh-72 missile tubes, a 30mm automatic grenade launcher, and no automatic protection system. Prototype vehicles underwent evaluation with no applique armor, missile tubes, or commander's RWS, but this configuration was never accepted into service and only exists as a trials variant or factory baseline variant.

All BSCh-12s delivered to Menghean Marine Infantry units are armed with the 35mm version of the Type 110 autocannon. The 50mm version is apparently being held out as a future upgrade to keep the BSCh-12 relevant if the EC introduces a heavy IFV protected against 35mm APFSDS ammunition. For the time being, the Menghean Ministry of National Defense has judged that 35mm APFSDS is adequate to defeat all existing EC IFVs and APCs over the frontal arc from combat ranges, and that 50mm APFSDS offers no concrete advantages as it is still inadequate to defeat existing MBTs.

Operators

• Menghe