Precizios Mechanika 2B9M/ACRV Mortar Carrier

     Notes: The 2B9M/ACRV is, as the nomenclature indicates, a heavily-modified version of the ACRV (itself a modified MT-LB) with a 2B9M Vasilek mounted in the rear of the vehicle.  The sides of the modified ACRV drop from their positions about a meter behind the commander’s and driver’s positions; the sides drop until they are straight out from the vehicle, where they are caught struts that are extended before the sides are dropped.  The rear of the vehicle also drops far enough so that the Vasilek can fire straight out and the dropped hatch extends straight out from the bottom of the crew compartment; it is also kept in a straight-out position by struts that are extended before the sides are dropped.  In extremis, the sides and rear may be allowed to completely dropped without the struts being extended, but this is not recommended except for a short time as doing this places a lot of stress on the hinges of the dropped sides and rear.  The drop sides allow the Vasilek to perform indirect fire missions, firing over either side of the vehicle.  By use of the drop rear, the Vasilek may also perform indirect fire missions, but it can also conduct direct fire missions.  The crew must exchange the sighting mechanism from one designed for indirect fire for one that is made for direct fire, in order to perform direct fire (or vice versa).  The vehicle’s turntable mechanism is also precise enough to allow the crew to “wing it,” in direct fire, sort of aiming and adjustment of aim by moving the turntable.

     For direct fire, the vehicle uses the PAN-1 sight, which has an 18-degree field of view with a magnification of 2.5x and a 9-degree view using a magnification of 3x.  The vehicle has an automatic fire control system that includes corrections for the gun for cant and height with a maximum of 10 degrees back or front for the vehicle, as well as a side slope of 10 degrees. (Any more leaning will require the crew to move the vehicle to a more level position.) The vehicle has an instrument to measure the effects of weather on a fire mission, a mortar ballistic computer, and inertial navigation with a computerized mapping system.  All functions, as well as fire coordinates from FISTs and FDCs, are tied together by the main computer.  The mortar ballistic computer also has enough power and storage space for it to act as a secondary, low-power, conventional computer.  The main computer has standard operating controls including a keyboard with extra keys specific to the vehicle’s mission, and a trackpad.  The mortar gunner normally operates the ballistic computer, the keypad and readout for which is mounted on the left side of the hull below the front of the drop side.  For direct fire, the Vasilek is partially stabilized and has the use of a laser rangefinder.  The crew can also use the laser rangefinder to perform indirect fire by direct lay. It should be noted that 2 minutes are required to fire the first round after a stop; part of this time is taken up by the computer, inertial navigation system, and mapping system synchronizing the vehicle’s position with that in the mapping computer, and the main computer digesting this computer. (It’s a robust computer system, but not necessarily state-of-the-art.)

     The interior of the 2B9M/ACRV is rather cramped; the computers and positions for their operator, the mortar crew, the Vasilek itself, and racks for a huge enough of mortar rounds take up a lot of room, especially since most of the mortar rounds are pre-loaded into the standard four-round clips that a Vasilek feeds from.

     It should noted that the 2B9M/ACRV is not designed for fire on the move, even with the Vasilek in direct fire mode; for fools who try it, there are Fire Control and Stabilization figures below, and if the 2B9M/ACRV is moving at more than one-quarter speed with the sides and rear dropped, there is a 10% chance per turn of movement that one of the hinges will be damaged enough that the hatch in question cannot be closed again.  Generally, when on the move, the 2B9M/ACRV has its drop sides pulled in and over the top of the vehicle, and the dropping rear pulled up and locked.  The Vasilek is turned so that it is facing straight left and locked in place.

     Being made from an ACRV chassis, the 2B9M/ACRV has much in common with the standard ACRV.  Of course, a standard ACRV does not have drop surfaces for its rear compartment, and the 2B9M/ACRV has an interior which is heavily modified for its role.  However, there are some differences between Hungarian-built ACRV vehicles and Russian ACRV vehicles.  Russian ACRVs use a YaMZ-238 engine developing 300 horsepower; Hungarian ACRV-based vehicles use a locally-produced JAMZ-238, a derivative of the Russian engine; this is a V-8 diesel developing 296 horsepower.  The transmission – indeed, the entire powerpack and power train – are locally-built instead of using Russian equivalents.  The transmission is manual; the Hungarian-built transmission has 6 forward and 1 reverse gear; while the Russian equivalent has 5 forward and 1 reverse gear.  Most other aspects are as a standard ACRV, except in minor details such as locally-built parts. The driver is on the front right side with a large hatch over him; this hatch has a small slit with a spring-loaded cover.  At night, an IR vision block may be slid into the slit.  The engine is to the left and below the driver.  On the left is the commander; he has a rotating cupola with all-around vision blocks, but on the 2B9M/ACRV, the commander has no weapon.  The commander and the driver both have large bullet-resistant windshields to their front; armored screens may be dropped over the windshield from inside the cab, with small vision slits.  He has a manual transmission, as does the standard ACRV.

     The 2B9M/ACRV was designed primarily for the export market, but Precizios Mechanika has yet to see any international interest, except from the Ukraine.  The Hungarian Army itself, however, is reportedly interested in buying a small run of these vehicles (or the BMP-based one, below).

The 2B9M/BMP-1 Mortar Carrier

     This variant is almost identical in fit and function to the 2B9M/ACRV carrier above, except for the BMP-1 (1976) chassis, and different mounting of the Vasilek.  Thusfar, only a few prototypes have been produced (probably five or less).  The vehicle is on the market, though so far only the Hungarian Army is reportedly interested in the vehicle.

     The 2B9M/BMP-1 has the basic BMP-1 chassis.  Instead of having a turret, the turret has been removed and a large superstructure installed at the rear of the vehicle.  The Vasilek is installed under this superstructure, along with other mortar equipment (as the 2B9M/ACRV above).  The superstructure is closed by sliding a hatch on either side which slides shut, and opens into a wide firing area.  There is a small drop hatch at the rear of the superstructure, though this is more to increase work area, as the Vasilek cannot be turned to fire through this opening.  Unlike the 2B9M.BMP-1, the Vasilek fires to the front of the vehicle, including in direct fire. In most other details, the Vasilek and its firing details remain the same as those of the 2B9M/ACRV, though the mortar must be moved back a short distance and to the rear to secure it for travel, and vice versa for firing. 

     Another big difference is that Precizios Mechanika has managed to stuff even more mortar rounds into the vehicle.  (This is also because of, while the 1B9M/ACRV has smaller exterior dimensions, The BMP-1 has larger interior dimensions.) The top deck hatch is deleted (its former position now taken up by the superstructure, and the commander moved to a small semi-triangular hatch in the left roof of the superstructure.  The cupola has all-around vision blocks, though the hatch does not rotate.  The front vision block is removable to be replaced by a night vision hatch, but the commander has no mounted weapon or even a mount.  The driver has his station on the left front, just ahead of the superstructure.  He has the standard BMP-1 hatch, with three vision blocks, one of which may be removed and replaced with a night vision block.  The front of the 2B9M/BMP-1 is virtually unchanged from the BMP-1; the rear doors are also retained, as they contain 66.5 liters of the fuel and there is a useful space behind them for gear.  The door firing port is deleted, as are the side firing ports.  The front clamshell doors and the small rear superstructure door can remain open while the vehicle is moving, even at full tilt, with damage to the doors.  The vehicle is powered by a locally-built version of the Russian UTD-20 300 horsepower diesel engine, along with a locally-built version of the Russian manual transmission.  Like the BMP-1, the 2B9M/BMP-1 has an NBC Overpressure system with a collective NBC backup, but it has the same ventilation problems when the hatches are closed.  The interior, while cramped, is not quite as cramped as the BMP-1, though that is a qualified, relative statement.

*These apply only when the vehicle is at a halt and in direct fire position; this vehicle is not capable of fire on the move, and can use direct fire for only a 40-degree arc to the rear of the vehicle or front of the vehicle (as applicable).