9K55 "Grad-1" multiple launch rocket system

Grad-1" is a part of the RDC:

• 9P138 fighting vehicle;
• the 9M28F unguided rocket projectile (other types of NURS of 122 mm caliber can also be launched);
• 9T450 transport vehicle (see photo);
• a set of 9F380 special arsenal equipment;
• training means.

The Battle Vehicle (BM) 9P138 repeats the basic design and layout solutions of the BM-21 Field Jet System M-21. The artillery part is mounted at the rear of the self-propelled chassis and represents a package of tubular guides on a swivel base. In contrast to BM-21, the guide package contains 36 barrels arranged in four rows (two upper rows have 10 barrels each, two lower rows - 8 barrels each). The artillery part also includes sighting devices, guidance mechanisms, and corresponding electrical and hydraulic equipment. To ensure stability at the rear of the wheel chassis, folding backstops with jacks are provided. Compared to the BM-21, the guide package is located at a smaller distance from the ground surface, which significantly simplified the process of charging the combat vehicle.

The fire control system allows for single and multiple firing. To ignite the powder charge of the rocket projectile, there are batteries used as power sources and a pulse sensor. The operation of the current pulse sensor can be controlled either from the cabin or remotely by means of a remote coil at a distance of up to 60 m from the PM. Shots can be fired at ambient temperatures ranging from -40° to +50°C.

BM 9P138 is located on the chassis of three-axle cross-country vehicle ZIL-131. It is equipped with a V-shaped eight-cylinder carburetor engine with an output of 150 hp at 3200 rpm. Clutch - single disc dry, five-speed gearbox with synchronizers to engage 2, 3, 4 and 5-speeds. The chassis is made on the wheel arrangement bhb. The wheels of the front driving axle are controllable. The suspension of this axle is dependent on longitudinal semi-elliptic springs, with hydraulic telescopic double-acting shock absorbers. Suspension of middle and rear axles is balancer suspension on longitudinal semi-elliptic leaf springs. The chassis has a centralized system of air pressure regulation in tires. When driving on the highway BM 9P138 has a maximum speed of 80 km / h. Its passage on rough terrain is quite high, without prior preparation the machine speeds up fords up to 1.4 m deep.

The BM can be carried by air in the cabins of medium military transport aircraft. The equipment includes a VHF radio station and firefighting devices.

Shots can be fired with all types of ammunition developed for the M-21 Field Rocket System:

• 9M28F with shrapnel head (standard)
• M-21OF with a shrapnel-type head end
• 9M22S (MZ-21) with ignition head part
• 9M28S with an incendiary header
• 9M28D with campaigning head part
• 9M28K cassette head unit equipped with anti-tank mines
• 3M16 with cassette head unit equipped with antipersonnel mines
• 9М519-1...7 set of shells with cassette head units in equipment with interference transmitters operating in CW and VHF radio bands
• 9M43 with head part for creating smoke fences
• 9M521 with a shrapnel-head part
• 9M522 with detachable shrapnel-head part
• 9M217 with cassette warhead, equipped with self- aiming warheads
• 9M218 with a cassette warhead in the outfit of cumulated shrapnel warheads

One of the archive documents of the State Archive Institution of the Tula region "State Archive" contains the following information about the results of the analysis of the projectile shells' design manufacturability, based on the reports of the head technological enterprise of R-6758 settlement, out. №62/10199 of II/VI-71 and № 62-18705 of 18.X.71, the head enterprise for the serial production of projectiles of the "Grad" type. A-3749, manufacturer of shell casings for the "Grad-I" system, Ya. G-4575 (TULGOSNITOCHMASH, nowadays FSUE "State Enterprise "Splav"). Technological analysis was performed in accordance with OST 84-76-69.

"In the construction of the body of the shell-shrapnel blowout system "Grad-I" used ~ 43% of the details borrowed from the standard shell M-21OF system "Grad".

At the stage of polygon testing for parts of projectile bodies progressive methods of blanks forming were used, further improvement of technological processes was carried out, proposals on provision of high manufacturability were considered.

Details and assembly units of "Grad-I" system shells are similar to "Grad" system shells in terms of materials used, heat treatment modes, galvanic, paint and heat protection coatings.

No special equipment is required to manufacture parts and assemblies. For the application of paint, galvanic and heat protection coatings the same equipment is used as for the parts of "Grad" system OEM shells.

The material efficiency of the projectile casings is the same as that of the standard projectiles and is not lower than the standard Km≥0.6.

Based on the technological analysis of manufacturing of "Grad I" system shells, it should be noted that the design uses a significant number of borrowed parts and assembly units of "Grad" system orbital projectiles, as well as assembly units and parts that differ slightly in terms of technological processes.

In addition, the technology of manufacturing original parts included in the design of the projectile system "Grad I".

As the general technological analysis of manufacturing of "Grad-I" system shells and the main indicators of manufacturability showed...manufacturability of "Grad-I" system shells construction is higher than manufacturability of "Grad" system shells.

Progressive technological processes were used for manufacturing of the main shell parts of "Grad-1" system, which provided for obtaining the parts with minimum labor intensity, high productivity, as well as the coefficient of metal use.

For example, the warhead body was manufactured by forging in one press operation from a special cold-rolled pipe with the specified mechanical properties in the delivery condition (σв ≥ 60 kgf/mm2). The material for the pipe was non-deficient structural steel grade 10 GOST 1050-60. Coefficient of use of a material made 0,75.

In accordance with Glavkom SV Directive No. 56I/I/006522 of May 4, 1972, the polygon-arming tests (PVI) of "Grad-1" system on ZIL-131 chassis were started.

In 1972 landfill tests were completed and the system was recommended by the commission on carrying out the mentioned tests for the Soviet army in the following composition:

• combat vehicle on the wheel chassis of "ZIL-131";
• transport vehicle on "ZIL-131" wheel chassis;
• Unguided rockets with fragmentation fragmentation warheads and incendiary electronic warheads;
• removable package of war machine guides for firing M-14OF rounds.

At the stage of landfill and wrestling tests the system's characteristics meeting the tactical and technical requirements were obtained:

• maximum range of fire with a shrapnel-head is 15 km;
• herd rate of fire: in the range I/X = 1/272; in the direction I/X = 1/117;
• number of war machine guides - 36 pcs;
• removable ammunition on transport vehicle - 54 rounds (1.5 rounds).

In addition to the shrapnel and fragmentation warhead, the 9M28 missile unit could be equipped with the 9M23 and 9M22C missiles.

The effectiveness of the shrapnel-flagged projectile was higher than that of the M-21OF projectile:

• in live force (Eub = 10kg/cm2) by 1.2 times;
• for non-armoured equipment (Eub = 135 kg/cm2) 2.8 times;
• on the light-armoured technics (Eube = 240 kg/m2) in 4,1 times.