"Pentagon convinced American public that the F-117 is "invisible" to radar. Evidently, Pentagon forgot to mention that to Yugoslav SAM operators."
According to thus-far declassified information, the US has only ever lost two of its Stealth Fighters in action; one each during the the NATO "wars" in Kosovo and the former Yugoslavia. One of these crashed. The other was shot down by one or two SA-6 missiles (Yugoslav Air Force officials also claimed the same was also hit with AAMs fired from one of their MiGs, though there seems to be little evidence of this).
The SA-6 is a surface to air missile (Russian designation ZRK-SD 'Kub') system manufactured by the Soviet Union for mobile defence of ground-based units - troops or other mobile assets - against low-flying threats like cruise missiles, helicopters and aircraft.
The system was deployed from about 1967 onwards and was/is probably used more widely than any other anti-aircraft missile system ever, by amongst others India, Israel, Arabia and Egypt. The US even has a few for pilot training purposes, but they didn't buy them. The SA-6 is the first completely mobile Russian anti-aircraft missile system; although the SA-4 has a tracked launcher, it still depends on stationary radars for targeting. SA-6 radars on the other hand are all mounted on tracked chassis (plural), able to follow the launchers over just as rugged terrain.
Design of the system began in the late 1950s by the Toropov Design Bureau, led by founder Ivan Ivanovich Toropov. Sources paint a rough picture of a rushed design that was paid for both in the time it ended up taking and in the career of Toropov. Research on the fundamentals that the functionality of the system would be built on took place during development of the design itself instead of before it, and components of the design that should have been tested before they were implemented were not. The test-firing of the "completed" design was the first time that many of the components of the 3M9 missile (the type the SA-6 would fire) had been tested at all. This showed, because the first 3M9s to be fired disintegrated in the air. This was in 1961.
No doubt mortified but also annoyed at the short shrift he had been forced to give to the due design process, Toropov asked his superiors at the Ministry of Armaments for more time to complete, but instead was sacked from his post and shunted over to the Ministry of Aviation as a department chairman, leaving one Andrey Lyapinov to take over his design team. This didn't seem to help, because the SA-6 was not certified operational until 1966 (about the same time as the SA-7), seen in public for the first time in 1967 when in the regular tradition it appeared in that year's May Day Parade.
There are three to four components to the SA-6 system: The 3M9 missile, the launcher, and one or two targeting and fire control radars. The missile itself is 5.7 metres long and 33cm wide. It has two pairs of diagonally-clipped delta wings midway along the length and four stabilising fins at the rear, spanning 1.5m from tip to tip. Propulsion is performed from launch by ramjet boosters which accelerate it to about mach 1.5, with a solid fuel rocket motor taking over afterwards, accelerating the 3M9 further to a maximum of about mach 2.8. It is effective at ranges of 3-24km and altitudes from 100m to 12km.
The 600 kilogram 3M9 carries a 56kg high explosive fragmentation warhead, which detonates on a proximity fuse. As with several preceding Soviet SAMs, there is limited guidance built into the missile itself: each has either terminal guidance, taking over from the battery radar once the missile nears its target, or an IR seeker which would find the target itself after initial direction from the battery radar. This is an immediate plus, since not only can the battery radar be turned off after the missile is launched, minimising the risk of it being hit by an anti radar missile, but it can be omitted from the process altogether, meaning an SA-6 battery can still function in a limited capacity if its radars have been knocked out.
The launcher is a tracked chassis with a rotating and elevating launch platform which carries three missiles. Impressively, "they" had progressed much in efficient used of materials by this point meaning that this launcher only weighs 15 tonnes, compared to the 30 that the SA-4's launch vehicle weighed. This meant more or less the same performance as the SA-4's launch vehicle was possible with a much smaller engine: a 240bhp V6 diesel engine gives a top speed of 27mph for a maximum of 160 miles.
Targeting and tracking in the SA-6 system is done by Straight Flush (possibly also used by the SA-11) and Long Track (as used by the SA-4, as well as the SA-8) radars. Both of these are mounted on their own tracked chassis, closely related to that of the launch vehicle. Straight Flush provides medium and short range target acquisition and tracking, as well as missile fire control. The vehicle has two radar receivers mounted on a rotating turret of sorts - the 12ft-wide search and targeting reflector is mounted halfway up the turret, which is topped by a 7ft parabolic dish that tracks targets once they are acquired. A Straight Flush radar can control three missiles at once but only against one target, so it's common to fire one or more missiles against a target, presumably so it can be downed as quickly as possible and other targets can be 'attended to' with minimal delay. Interestingly, modifications of the Straight Flush system (possibly by Polish recipients of exported models) include TV optical guidance systems, meaning that the radars can be shut down if there is a risk of attack from anti radiation missiles. The TV tracking system has the added bonus of reducing the minimum altitude of engagement from 100m to 80m.
Long Track is an optional long range targeting component for the SA-6 system. "Optional" in the sense that it is essential if potential targets are likely to be at altitudes above 10km (the maximum targeting altitude of the Straight Flush radar). Long Track is mounted on a heavily modified AT-T chassis and carries a large elliptical parabolic reflector, which detects targets around 150km away and up to 30km high, passing them to the Straight Flush radar when sufficiently close to track.
A full SA-6 battery consists of one or both of the aforementioned radars, with three to four launch vehicles and accompanying supply trucks. From wakeup, an SA-6 battery can target, IFF interrogate, track and launch against a target in about three minutes. If the radars are already running this only takes about 30 seconds or less.
The SA-6 has been referred to as the "grandfather" of all SAMs. Although production finished around twenty years ago it is probably still the most ubiquitous Soviet SAM design (which it seems the SA-11 and SA-17 are descendents of) with over 850 launchers built in total and exports to 22-25 countries (although it is retired in Russia - shortly before the breakup of the Soviet Union it was replaced by the SA-11).
It has probably seen more action than any other Russian SAM system: it was used during the 1967 Six-Day War (shot down 65 Israeli aircraft, 95 missiles fired in total), the 1971 India-Pakistan War, and more recently during the 1991 Gulf War, and the NATO actions in the former Yugoslavia and Kosovo. Many aircraft losses (particularly during the Gulf War) were due to SA-6 battery operators using the aforementioned technique of not turning their radars on for more than a few seconds and relying on the IR homing of the missiles themselves, thus not alerting the pilots to the danger.
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There are few distinct sources for this subject - although Googling the SA-6 will turn up many separate sites it appears several of the more verbose descriptions copy very closely or verbatim from John Pike's (of FAS) writing on the subject. As always, please /msg any mistakes to me and a correction will follow. In particular, illumination on combat losses of the F-117 would be appreciated, as sources seem rather confused.
Sources:
- Pike, John; "ZRK-SD Kub 3M9 SA-6 Gainful";
<http://www.globalsecurity.org/military/world/russia/sa-6.htm>
- (Author not specified); "The SA-6 "Gainful" ZRK-SD Kub SAM system";
<http://www.aeronautics.ru/nws002/kub.htm (stats)>
- N.A.S.O.G; "SA-6 GAINFUL";
<http://www.nasog.net/datasheets/armour/spsam/SA_6_Gainful.htm> (stats)
- Rakshak, Bharat; "ZRK-SD KVADRAT (SA-6 GAINFUL)";
<http://www.bharat-rakshak.com/LAND-FORCES/Army/SA-6.html>
- Fresh Productions; "Kub (SA-6 Gainful)";
<http://562.50megs.com/Kub.htm> (probably copied)
- (Author not specified); "Note on the SA-6 Gainful missile";
<http://meltingpot.fortunecity.com/chad/95/sa-6.html>
- Missile Index; "SA-6 Gainful";
<http://www.index.ne.jp/cgi-bin/search?cat=missile_e&plate=type01b.html&fid=sa6&imgpath=/missile_e/gif/>
- Armtech; "SA-6 GAINFUL Low to Medium Altitude Surface-to-air Missile System";
<http://www.star.co.yu/armtech/pages/tekst019.htm>(probably copied)
- (Author not specified); "A Lost Illusion";
<http://www.aeronautics.ru/f117down.htm>
- Vogelaar, R.; "F-117 Nighthawk";
<http://www.zap16.com/mil%20fact/f-117.htm>