The designers have proposed several options to set the guns on the tracked chassis:
1) The imposition of the trunk of a 180-mm towed gun S-23 on the chassis of the T-55 with a range of conventional weapons — 30 km, active-Rockets — 45 km. This project has received the designation "Pion-1";
2) the imposition of the barrel of 210-mm gun S-72 experimental crawler ("object 429") with a range of conventional weapons — 35 km, active-Rockets — 50 km on the chassis of the "object 429A";
3) application of the trunk of a 180-mm coastal guns MU-1 (Br-402) on the chassis of the T-55;
4) placed in the control room — on the chassis borrowed from the T-64 — 203.2-mm cannon with improved ballistic performance, developed by specialists of the Leningrad Kirov Plant. Either the gun of the same caliber open mount on the "object 429", providing her soft shoe, improving sustainability in the management of the fire.
After much debate at the beginning of 1969 it was decided to take the caliber of 203 mm. In September 1969, the Leningrad Kirov Plant submitted a preliminary design of MOS ACS "Peony" on the chassis of the T-64 in the open shearing performance, and the plant "Barricades" — a preliminary design based on the chassis of the object 429 in the outdoor version. As a result, it was decided to develop the ACS based on the object 429 in the outdoor version. Joint resolution of the Central Committee of the CPSU and the USSR Council of Ministers on July 8, 1970 № 427-151, it was decided to design a 203.2 mm self-propelled gun 2S7 "Pion" with a range of 32,000 m conventional ammunition and 42,000 m — active-reactive. March 1, 1971 Grau approved refined tactical and technical requirements for the designed system. They offered to explore the possibility of using special shot ZVB2 of 203-mm howitzers B-4. Maximum range conventional 110-pound projectile was determined at 35 km, and the minimum bezrikoshetnaya — 8.5 km. Firing range of active-Rockets was 40-43 km. The lead developer was prescribed design office number 3 of the Leningrad Kirov Plant.
Artillery unit developed Volgograd plant "Barricades" under the leadership of G. Sergeyev. Artillery unit Volgograders youcomplete with respect to the classical scheme, but with a few twists. In particular, the barrel was not a one-piece and detachable, which consisted of a free pipe, casing, breech, couplings and bushings. These guns offered in the 70-ies. XIX century. Specialist Obukhov factory AA Bells. The fact that a particularly powerful artillery systems peculiar to rapid wear of the threaded portion of the weapon. Unusable monoblocks in such cases to send a replacement for special enterprise that requires considerable time during which the instrument is idle. At the same collapsible onDaubney operation is easy to navigate in the artillery workshops located in the frontal rear.
After the factory and state tests in 1975 self-propelled gun was adopted by the Soviet Army and put into mass production. Artillery unit was made on the Volgograd plant "Barricades". At the Kirov plant produces special chassis "to 216" and the final assembly tools.
In addition to the USSR 2S7 was in service in Poland and Czechoslovakia (later the Czech Republic). At present (2010) 2S7 is in service with Russia, Ukraine, Belarus, Azerbaijan.
2S7 self-propelled gun is designed to perform the following tasks:
— destruction and suppression means of nuclear destruction, artillery, mortar and other fire equipment and technology;
— the destruction of field and permanent defense structures;
— suppression and destruction of the rears, and points of control of troops and artillery;
— suppression and destruction of manpower and equipment in the areas of concentration, and on the borders of the deployment.
Self-propelled gun 2S7 performed by reckless scheme with the placement of weapons in the open stern of the crawler. 2S7 consists of a 203-mm gun 2A44 and mechanized crawler.
2A44 cannon consists of the barrel, bolt, firing mechanism, Hopper, cradles, chock device rotating and hoisting mechanisms, 2-pneumatic balancing devices pull-type, top machine, iron sights and loading mechanism. On the cannon barrel applied to the casing, and a two-stroke piston valve (with a plastic seal of the "Bange"), opened up. The shutter is equipped with impact-type firing mechanism, a special mechanical drive to automate the process of opening and closing the shutter (in alarm mode, these operations can be performed manually), and balancing devices to facilitate the opening of the gate. In the firing mechanism made nest for shop primer tubes. Release is produced by electric trigger or trigger cord (in an emergency).
Cradle of cylindrical type set top machine. To it are attached cylinders chock device arc gear lifting mechanism, the sensor length fromkata and bracket for mounting sights. Abouttivootkatnoe device includes a structure of its own hydraulic brake system rollback to equalize the volume of fluid and two hydro-pneumatic recuperator. Length of roll withis not more than 1400 mm. Machine mounted on the top lift and swivel mechanisms and balancing device. Pointing the gun in the vertical and horizontal planes, by means of hydraulic actuators or manually (in an emergency). The vertical guidance from 0 ° to +60 °, the angle of the horizontal guidance — ± 15 ° relative to the longitudinal axis of the machine.
Failure to use a muzzle brake provided muzzle wave of low pressure in the workplace and refuse to allow installation of special protection for the calculation.
The gun is equipped with a semi-automatic hydraulic loading system, allowing to carry out this process at all angles of elevation of the barrel. Manage all operations of loading mechanism is a remote castle. First, the bolt is placed in a shell forthat — a propelling charge, and at the last stage (before the shutter closes) into the firing mechanism is inserted by hand primer tube. After the shot tube used capsule is ejected automatically when yo
u open the shutter.
When supplied with a ground shot ACS uses a two-wheeled hand truck. The cart consists of a frame with wheels and removable stretcher. Stretchers are separated when lifting the projectile from the ground and loading shells on a tray dosylatelya. There's also hand-carry the stretcher without trolley. To supply ammunition to the ground, an additional 6 people.
Sights consist of mechanical device D726-45, PG-1M panoramic, optical sight OP4M-99A, artillery collimator K-1, Sat 13-11 and milestones fixture "Ray-S71M." ACS can lead fire, as from the closed position, and direct fire.
To fire the gun used caseless rounds of separate loading, consisting of a projectile and propellant charge (full or reduced). Powder propellant charges are enclosed in a linen envelope and stored in an airtight container.
The main shells are high-explosive projectile OF43 and active-missile 3OF44. Mass of high-explosive projectile — 110 kg, the mass of explosives — 17.8 kg, the maximum range on a full charge — 37.5 km, the initial velocity — 960 m / s. Mass of active-Missile — 103 kg, the mass of explosives — 13.8 kg, the maximum range — 47.5 km. Also, the gun is designed concrete-shell spetsboepripasov with nuclear warheads and chemical bomb.
Ammunition consists of 40 shots, 4 of which are available on a self-propelled installation, and the rest are transported in the accompanying transport vehicle.
The maximum rate of gun — 1.5 shots per minute. The following shooting modes:
— 8 shots for 5 minutes;
— 15 rounds for 10 minutes;
— 24 shots in 20 minutes;
— 30 rounds for 30 minutes;
— 40 shots in an hour.
Additional armament consists of MANPADS, antitank grenade launcher RPG-7, F-1 grenades, four machine gun and a flare gun.
Chassis frame is a welded box-section design that cross partitions divided into four departments: control, power, calculation and stern. In front of the case taken by management office with three workstations for the commander, driver and gunner, for it — the engine compartment from the main and auxiliary power units, office for four members of the calculation and the aft compartment, which houses the batteries, fuel tanks and to store ammunition. Cabin crew taken out far ahead. In addition to its primary purpose, it also serves as a counterweight to the gun installation.
Running gear consists of a front wheel drive, seven pairs of rollers, six pairs of support rollers and rear guide wheels. The machine used tracks with rubber hinge, and independent torsion bar suspension with telescopic hydraulic shock absorbers (the first, second, sixth and seventh pairs of rollers). Many sites chassis borrowed from the T-80. Mechanical transmission with bevel gearbox and final transmissions borrowed from the T-72 tank.
To appreciate the very significant recoil force gun in the rear of the chassis is mounted chassis lowered by a hydraulic plow dozer type. He dug into the soil to a depth of 700 mm and provides good stability when firing the gun. Contribute to improve the sustainability lowered by hydraulic steering wheels tracked chassis and suspension assemblies are blocked Hydromount rollers. At low elevations and the use of reduced charges of shooting a gun can be carried out without dropping the opener.
As the primary propulsion system for self-propelled gun on a 12-cylinder V-twin four-stroke V-46-1 turbocharged 750 hp The auxiliary power unit consists of a 4-cylinder diesel engine 9R4-6U2 power of 18 kW and a gearbox with a starter-generator and hydraulic pump.
2S7 has two observational night vision TVNE-4B, R-123 radio station, by means of internal communication 1V116, fire alarms, filter devices, a heating system, tank decontamination kit.
Cannon serves calculation of 14 people, 7 of them are self-propelled and crew on the march are placed in the offices of the control and calculation, and the rest — in the accompanying installation of a truck or armored personnel carrier.