2K12 Kub Russian SAM

The 2K12 "Kub" mobile surface-to-air missile system is a Soviet low to medium-level air defence system designed to protect ground forces from air attack. "2К12" is the GRAU designation of the system. Kub is known in the west by its NATO reporting name "Gainful" as well as the US Department of Defense designation SA-6.

Each 2K12 battery consists of a number of similar tracked vehicles, one of which carries the 1S91 (SURN vehicle, NATO designation "Straight Flush") 25 kW G/H band radar (range 75 km/47 miles) equipped with a continuous wave illuminator, in addition to an optical sight. The battery usually also includes four triple-missile transporter erector launchers (TELs) and four trucks each carrying three spare missiles and a crane. TEL is based on a GM-578 chassis, while the 1S91 radar vehicle on a GM-568, all developed and produced by MMZ.

The 2K12 system shares a lot of components with the 2K11 Krug (SA-4) system. In many ways they are designed to complement each other; 2K11 is effective at long ranges and high altitudes, 2K12 at medium ranges and intermediate altitudes.

The system is able to acquire and begin tracking targets using the 1С91 самоходных установок разведки и наведения ("Self-propelled Installation for Reconnaissance and Guidance" / NATO: "Straight Flush" radar) at 75 km (47 miles) and begin illumination and guidance at 28 km (17 miles). IFF is also performed using this radar. It can only guide one or two missiles to a single target at any time. The missile is initially command guided with terminal semi active radar homing (SARH), with target illumination provided by the "Straight Flush" radar. Detonation is via either the impact or proximity fuze. On the latest models, this vehicle is also fitted with an optical tracking system which allows engagement without the use of the radar (for active RF emissions stealth reasons, or due to heavy ECM jamming) in which case the effective altitude is limited to 14 km/46000 ft. The optical tracking method also allows engagements to altitudes below that where the radar is able to track targets. Maximum target speed is around Mach 2 for head-on engagements and Mach 1 for tail-chase engagements. Top speed of the missile is approximately Mach 2.8.

In contrast to the elaborate Patriot missile or even the simpler Hawk system fielded by US forces, most of the system rides on two tracked self-propelled vehicles, rather than towed or mounted on trucks, and either the launcher or control vehicle can be set to launch in only 15 minutes after changing location.

Missiles

The fairly large missiles have an effective range of 4–24 km (2.5–15 miles) and an effective altitude of 50–14000 m (164–45,931 ft). The missile weighs 599 kg (1321 lb) and the warhead weighs 56 kg (123 lb). Top missile speed is approx. Mach 2.8. The combined propulsion system 9D16K included solid fuel rocket motor which, when burned out, forms the combustion chamber for a ramjet in a pioneering design putting this missile far ahead of its contemporaries in terms of propulsion.

The missile was fitted with a semi-active radar seeker 1SB4, designed by MNII Agat, which was able to track the target by Doppler frequency since the start. Chief Designer of the seeker head was Yu.N. Vekhov, since 1960 - I.G. Akopyan.

In 1977 a new version, the 3M9M1 (DoD designation SA-6B) was created with three missiles fitted onto a different chassis (the same as that of the 9K37 "Buk" (NATO reporting name "Gadfly" / DoD SA-11 ), the 2K12 effective replacement) with an integrated "Fire Dome" missile guidance radar. For comparisons between the 2K12, 9K37, see the 9K37 Buk entry.

An earlier incremental upgrade saw the 2K12 missiles replaced with the 2K12E versions and this system was known as Kvadrat ("Квадрат", meaning square). This name was derived from the most common arrangement pattern of the military vehicles of the 2K12 complex, when the 1C91 radar is located at the center and 4x2P25 TELs at the vertices of a square around the radar.

1S91 radar

SURN 1S91 vehicle included two radar station - a target acquisition and distribution radar 1S11 and a continuous wave illuminator 1S31, in addition to an IFF interrogator and an optical channel.

While 1S31 antenna was installed on the upper section of the superstructure and the 1S11 on the lower, they could turn around independently. To make the height of the vehicle lower the central cylinder was able to hide inside the prime mover.

The acquisition range of the radar was reported as 50 km (31 mi) for the Phantom II type target.

Total weight of the 1S91 vehicle with a crew of 4 was 20.3 tonnes and 2P25 vehicle with 3 missiles and a crew of 3 was 19.5 t.

Additional radar

The 2K12 can also be used at a regimental level, if used as such it can be accompanied by a number of additional radar systems for extended air search at longer range and lower altitude, to supplement the 1S91 "Straight Flush". These systems include the:

• P-12 "Spoon Rest", a VHF early warning radar (also used by the SA-2), with a 200 kilometres (120 mi) range.
• P-40 "Long Track", an E band early warning radar (also used by the SA-4 and SA-8, with a 370 kilometres (230 mi) range.
• P-15 "Flat Face A", a UHF early warning radar (also used by the SA-3, with a 150 kilometres (93 mi) range.
• "Thin Skin" or "Side Net" E band height finding radar (also used by the SA-2, SA-4 and SA-5, range 240 km/148 miles)
• "Score Board" IFF radar

The "Spoon Rest" and "Thin Skin" are mounted on a truck, "Long Track" on a tracked vehicle (a modified AT-T) and "Flat Face" on a van. It is unknown what kind of mounting the "Score Board" has.

Without the P-40 "Long Track" mobile radar vehicle, the 2K12 is unable to track aircraft at high altitudes.

2K12 Kub NATO reporting name: Gainful
Type	Tracked medium-range surface-to-air missile system
Place of origin	Soviet Union
Service history
In service	1970–present
Used by	See list of operators
Wars	Yom Kippur War Chadian Civil War Iran-Iraq War Gulf War Yugoslav wars
Production history
Designer	NIIP/Vympel MMZ (GM chassis)
Designed	1959
Manufacturer	Ulyanovsk Mechanical Plant (SURNs) ZiK (TELs)
Produced	1968–1985
Variants	2K12 Kub, 2K12E Kvadrat (export version), 2K12M3, 2K12M4
Specifications (2K12 Kub)
Primary armament	3 9M336 (or variants) guided missiles