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OT - Yugoslavia's secret SAMs


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I just found this on Jane's site. Thought it might interest some of the forum members. Maybe we should have a general aviation forum in the english sub-forums. Just a thought.

 

Yugoslavia's secret SAMs

Seymour Johnson

 

In a 'crash' programme carried out during the 1999 NATO air campaign against their country, engineers in the former Yugoslavia created two-stage anti-aircraft missiles (AAMs) by mating infrared (IR) guided Russian air-to-air weapons with locally developed boosters, writes Seymour Johnson. Both were deployed for combat and at least one of these improvised weapons may have been used in action against NATO aircraft.

 

This concept of utilising AAMs as surface-to-air missiles (SAMs) had first been explored in the mid-1990s, when the Bosnian Serb Army (VRS) created a truck-mounted system in which R-3/K-13 (AA-2 'Atoll') passive IR guided missiles were mounted on a twin-rail launcher carried by a TAM-150 truck. This was a field modification, done without any formal research and development work, and seems never to have been given an official designation.

 

A simpler system, known as the Pracka (Slingshot), mounted an R-60 (AA-8 'Aphid') missile on an improvised launcher based on the mounting of the towed M55 20 mm anti-aircraft gun (see JMR November 1999, p1). In practice, this could have little more combat-effectiveness than a slingshot, having obvious shortcomings such as a very limited range.

 

JMR understands that two two-stage missile systems, designated RL-2 and RL-4, were hurriedly developed by the VTI (Vojno-Tehnicki Institut = Military Technical Institute) and VTO (Vazduhoplovno-Opitni Centar = Air Force Testing Centre) during the NATO bombing campaign in 1999.

 

Prototypes of both systems were built, based on the chassis of the Czechoslovak M53/59 30 mm self-propelled twin-barrelled anti-aircraft gun, more than 100 of which were in local service.

 

The missile for the RL-2 was an R-60MK fitted with a tandem booster of similar diameter. The latter seems to have been created by taking the rocket engine from an unguided artillery rockets and fitting it with large fixed cruciform tail fins. The booster of the RL-2 is about 2.25 m long and between 120-130 mm in diameter. It is probably based on the locally manufactured 128 mm-calibre artillery rocket.

 

After stripping the guns, ammunition magazines and associated hardware from an M53/59, technicians installed twin launch rails for the new missile. These rails were based on the APU-60-1DB1 (izdeliye P-62-1DB1) pylon/launch adapter that was used to install the R-60 on an aircraft.

 

The RL-4 missile was created by mating the Russian R-73 (AA-11 'Archer') with a tandem booster, and fitting this to a single launch rail mounted on another M53/59. In this case, the launch rail is based on the APU-73 (Izdeliye P-72) pylon/launch adapter.

 

The booster of the RL-4 seems to be 1.25-1.30 m long and 195-230 mm in diameter. The latter figure is significantly smaller than that of the locally produced 262 mm artillery rocket, which might seem a logical source for a suitable booster. One source tells JMR that the boosters of the RL-2 and RL-4 were probably based on the 57 mm S-5 unguided air-to-air rocket. This is not the case with the RL-2 but the presence of six nozzles at the rear of the RL-4 booster raises the possibility that this may have been created by bundling six VRZ-57 rockets into a casing. (The VRZ-57 is the local equivalent of the Russian S-5 rocket).

 

Each booster has a small blue logo at about its midpoint. One source tells JMR that this is probably the logo of Vazduhoplovni Zavod Moma Stanojlovic (sometimes referred to as VZ Moma), an aircraft overhaul and maintenance facility located at Batajnica airbase. This facility repairs and maintains all the air-to-air missiles in local service, as well as overhauling and maintaining fighter aircraft such as the MiG-21 and helicopters such as the Mi-8, SA 341/SA342 Gazelle, Alouette, Canadair, Mi-2, and Utva 75. VZ Moma also has its own production line for some aircraft spare parts.

 

On unexplained feature of the RL-4 is the presence below the launch rail of what looks like a large grey-coloured gas bottle. At first sight, its possible role could have been to provide an external source of coolant for the R-73 seeker; this seems unlikely, however - the only connection between the bottle and launcher seems to be an earth (grounding) wire. The possibility that it powers some form of pneumatically actuated launcher-arm elevation system seems equally unlikely.

 

First reports of a Serb-devised SAM system based on the M53/59 mobile anti-aircraft gun appeared in late 1999. These described a system in which two R-73 missiles (without boosters) were mounted on rail launchers. It is not clear whether this was a third improvised missile system (perhaps designated R-1 or R-3?), or if these reports confused the single-round R-4 and twin-rail R-2. One local source told JMR in late 1999 that the vehicle-mounted R-73 had proved successful. He added: "It is a great pity that we didn't convert more of them!" The more sensitive seeker head, improved search pattern and much greater range/ceiling of the R-73 based system had posed a significant threat to NATO aircraft.

 

Some modifications to the R-60 and R-72 must have been necessary to match them to their new role as the second stage of a two-stage missile. Some method must have been devised to inhibit the normal motor firing signal passed from the guidance section and replace it with one initiated by separation of the booster. The RL-2 interstage is a tubular section with holes on either side. A wire or cable emerges from one of these holes and runs forward to connect to the R-60 missile. It is not clipped or restrained in any way and seems more like an improvisation than an engineered feature. On the RL-4, a cage-like structure surrounds the gimballed nozzle of the R-73 and connects the missile to its booster.

 

It's probable that no modifications were necessary to the normal three-stage safety and arming mechanisms of the original missiles. The first two stages are electrical and mechanical, and would be initiated via the launch adaptors (and separation from the launch adaptors) in the same manner as for an aircraft launch. The third and final stage would be commanded by missile acceleration - a condition probably met by operation of the booster - and would probably have armed the missile at a height above the ground sufficient to forestall premature initiation of the missile's proximity fuze. The unmodified missile autopilots should have been able to cope with the launch disturbances likely to be encountered.

 

One feature of the original anti-aircraft gun that had been retained is the gunner's position on the left-hand side of the mount. This allows be operator to be seated and protected by frontal, side and rear armour. In the RL-2 and RL-4, this became the missile operator's position.

 

JMR has no information on whether any sort of ranging, target-designation or cueing system was provided, or how sophisticated the missile control panel was. At the very least, there is likely to have been an aural indication of seeker head lock-on and, ideally, a further tone to indicate when the missile seekers were approaching gimbal and tracking-rate limits.

 

On the RL-2, engineers would have had to provide either some sort of sequencing for a twin-round salvo launch, or a selector switch that would have allowed one launch rail or the other to be activated.

 

The RL-2 and RL-4 are unlikely to have been able to conduct quick-reaction firings against targets of opportunity but must have depended on some form of air-defence command post or forward reporting system to at least give some idea of direction and time of threat arrival.

 

Both prototypes were built by personnel in VTO and VTI workshops; JMR has no information about how many (or indeed if any) test launches were carried out. The prototypes remained in service during the NATO bombing campaign in 1999. Unofficial reports suggest that the RL-4 may have been used in action but there is no evidence of RL-2 rounds being fired against NATO aircraft. When hostilities ended, both systems were removed from service and returned to the VTI.

 

In its air-launched form, the R-60 is credited with a minimum range of 150 m and a maximum range of 10 km. In cases where the target parameters such as range are estimated visually and not supplied via aircraft-mounted sensors (the likely conditions for an RL-2 launch), the manual of the MiG-29 recommends that rear-quarter targets be engaged at 0.3-1.5 km, adding that front-quarter targets (other than head-on) be engaged at 1.5-12 km if non-manoeuvring and at no more than 5 km if manoeuvring.

 

For the RL-2/R-60 to be effective against front-quarter afterburning targets the guidance system would have to be switched to high-gain. In the air-to-air role, this would normally be done via the aircraft weapons control system.

 

According to the VTI, the maximum range of the RL-2 was 7.5 km. The speed and aspect of the target was not specified. In its R-73M1 form, the AA-11 has a minimum range of 300 m and a maximum range of 20 km. The VTI credits the RL-4 as having a maximum range of 8.6 km.

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In other news, the US ARMY retured Chapparal a looooong time ago ...

 

Very interesting stuff, but unlikely to be particularely effective against high-flying night-raiders dropping PGMs.

 

Totally sueless against high-flying bombers, too.

[sIGPIC][/sIGPIC]

Reminder: SAM = Speed Bump :D

I used to play flight sims like you, but then I took a slammer to the knee - Yoda

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This isnt anything special, the Iraquis were also very affond of little scientific experimets with their frankanstanization of SAM and missile equipment. But these "home brew projects" usualy meant their sensory array to be seriously limitated.

 

In the opening night (read sun rise) of the last gulf war I observed on TV live, and then confirmed months later that the Iraquis were firing missiles to the air along with all that AAA. i observed "bolts" describing "s" turns in the air.

 

Either the Iraquis fired them in the hopes of getting a sniff of US aircraft while in flight or those could very well be some of the reported missiles with IR lockon from the rail.

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Or they were going nuts from jamming and chaff.

 

...wich means they would have been launched with radar asssitance wich didnt happen. The Iraquis long have learned to know how bad HARMS are once the US aircraft get a sniff of their radars. Wich at this time were scarce items BTW.

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My PC specs below:

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CPU: AMD RYZEN 3900X (12C/24T)

RAM: 32 GB 4266Mhz (two 2x8 kits) of trident Z RGB @3600Mhz CL 14 CR=1T

MOBO: ASUS CROSSHAIR HERO VI AM4

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