17 December 2010

Soviet Wild Weasels: Part Two (Aircraft)

Yakovlev Yak-28PP "Brewer-E"
Last night we took a look at the nuts and bolts of Soviet suppression of enemy air defenses (SEAD) doctrine and tactics. Tonight we'll continue along that them with a look at the aircraft that filled the role of  "Wild Weasels" in the Soviet air forces. Like the United States, the Russians had put into service several specialized aircraft that were used to knock out and/or jam enemy radars and surface-to-air missile sites. These aircraft were based upon established production types much in the same way the USAF Wild Weasels were adaptations of production fighter aircraft. The first aircraft to fill this role was the Yakovlev Yak-28N, an experimental adaptation of the Yak-28 "Brewer" attack aircraft. This version of the Brewer was the first Russian development for a Wild Weasel-class aircraft; work began by OKB Yakovlev in 1964-1965 with a production Yak-28I being set aside in 1965 for conversion to the -28N configuration. The attack Yak-28I had the "I" suffix as it was equipped with the Initsiativa-2 ground-mapping/bombing radar in a ventral radome aft of the nose gear. On the Yak-28N, the Initsiativa-2 radar was replaced by radar pulse detection unit that would seek out and locate enemy radar emissions and provide targeting data to Raduga Kh-28 (NATO code name AS-9 "Kyle") missiles, one each under the outer wings. The Kh-28, which I'll discuss in a subsequent post, was the first Russian anti-radiation missile to be fielded with the first operational examples coming out in 1964. 

By the time operational testing of the Yak-28N was completed around 1972, it had been far outclassed by contemporary Russian and American designs and the project was canceled. However, the work that had been put into the Yak-28N wasn't wasted as the Soviet air forces still needed a battlefield electronic warfare aircraft that better performance and was more flexible than the existing design in use, the Tupolev Tu-16PP Badger which clearly by 1972 was too big and too slow to survive in hostile airspace. The Yak-28 was again used as the basis for the Yak-28PP electronic warfare aircraft that crammed the jamming equipment of the Tu-16PP into a much smaller airframe. All of the armament provisions of the Yak-28 were deleted and four different jamming systems were installed in the Yak-28PP, which was marked by a number of dielectric bulges and blisters on the fuselage. The jamming systems generated so much heat that two heat exchangers were installed in the lower aft fuselage ahead of the aft bicycle gear to help cool the avionics. The outer wing pylons were fitted with rocket pods that fired chaff ahead of the aircraft to help sow chaff corridors to protect inbound strike packages. Below each engine nacelle of the Yak-28PP was a system for deploying bundles of fiberglass-based chaff strips in mass quantities. The role of the Yak-28PP was to accompany inbound strike packages with three of the ECM -28PPs sowing a chaff corridor on each side of the strike aircraft formation as well as using its powerful jamming equipment to blind NATO air defense radars. The first Yak-28PPs completed their State acceptance testing just as the Yak-28N was canceled. Most of the Yak-28PPs that were built (NATO code name "Brewer-E") were based with the Soviet forces in East Germany. 

MiG-25BM armed with Kh-58 missiles
The cancellation of the Yak-28N in 1972 came about due to the arrival of an aircraft with significantly higher performance that would become the first Russian production Wild Weasel-class aircraft, the Mikoyan MiG-25BM "Foxbat-F" based on the production interceptor version. It was recognized early on in the Foxbat's flight test program that a high-flying, high-speed aircraft would make an ideal SEAD aircraft- as it was proved itself immune to interception during operations over the Sinai prior to the Yom Kippur War, a SEAD Foxbat could out-fly defending fighters, fire its anti-radiation missiles, and streak back with impunity. While early anti-radiation missiles like the Kh-28 mentioned already were heavy, the newer generation of anti-radar missiles like the Raduga Kh-58 (NATO code name AS-11 "Kilter") were much lighter and imposed little performance penalty on the Foxbat. 

Mikoyan MiG-25BM Foxbat-F in East Germany
At first the MiG-25BM was to be a dual-role reconnaissance/SEAD aircraft, the concept being that it would use its SEAD capability to allow it to penetrate deep into NATO airspace to complete its reconnaissance mission. By 1977 both the Soviet air forces and Mikoyan realized that the aircraft would be compromised in both roles and different Foxbat variants were developed for each role, with the MiG-25BM being the definitive SEAD variant. The MiG-25BM featured an integrated avionics package called Yaguar (Jaguar) that not only detected and located enemy radars, but it also networked with the Yaguar systems of other MiG-25BMs to allow a "wolf pack" of SEAD Foxbats to operate deep into NATO territory and share data and targeting information with other members of the wolf pack. The Yaguar system included target designation functions that cued the seeker heads of the four Kh-58 missiles that the MiG-25BM carried. In addition to the missiles, nuclear warheads could also be delivered to either knock out SAM missile sites or generate an EMP to short out communications and electronic systems. Several internal active ECM jammers were also carried which not only protected the MiG-25BM from air defense radars but could also counter fighter radars as well. The Foxbat-F was in production from 1982 to 1985, but the complex systems of the aircraft meant that only 40 examples were built. Nearly most were assigned to units stationed in East Germany and were unusual in being the only Foxbats to wear camouflage as the reconnaissance and interceptor variants were gray in color. Despite production ending in 1985, continued technical problems that had to be resolved meant that the first MiG-25BMs weren't operational in East Germany until 1988 with the Group of Soviet Forces Germany (GSFG), which ultimately withdrew from German soil in 1994. 

Kh-58 missile on an Su-24M, Fantasmagoria pod below it
The last SEAD aircraft developed for the Soviet air forces was the Sukhoi Su-24M "Fencer-D", but by this time the Fencer-D was less an dedicated SEAD asset and more an attack aircraft that had SEAD capabilities. Unlike the Yak-28N and the MiG-25BM that housed a large amount of equipment internally, technological advances meant that the Fencer-D could carry most of the radar detection and location equipment in a pod mounted on the centerline underfuselage which was called Fantasmagoria, with -A, -B, and possible -C version depending on the internal configuration of the pod. This was similar to the USAF where the Lockheed Martin F-16CJ replaced the specialized F-4G Phantom Wild Weasel. The F-16CJ had a small pod called the HARM Targeting System (HTS) that performed the same role as the Russian Fantasmagoria pod. The Su-24M could carry two kinds of anti-radiation missile, either the Kh-58 as was used by the MiG-25BM or the newer Kh-31 (NATO code name AS-17 "Krypton") missile. 

Sukhoi Su-24M Fencer-D, note the Fantasmagoria pod
The closest that Russian SEAD aircraft came to being committed to action came during the Soviet invasion and occupation of Afghanistan fron 1979 to 1988. During the war, Tupolev Tu-16 Badgers were used to bomb Mujaheddin positions, but were often tracked by Pakistani air defense and early warning radars. It was proposed to use the Su-24Ms to knock out the Pakistani radars which were providing warning information to Mujaheddin forces, but it was realized that it represented a significant escalation of the conflict and only limited cross-border raids were conducted with SEAD protection. During the Russian-Georgian War of 2008, it is believed that Su-24Ms were used against Georgian air defense positions, but poor tactical coordination resulted in the Georgians shooting down two Fencers. 

The last installment of this series will take a closer look at the anti-radar missiles that the Russians fielded for their SEAD assets. Stay tuned!

Source: Wild Weasel Fighter Attack: The Story of the Suppression of Enemy Air Defences by Thomas Withington. Pen and Sword Aviation, 2008, p100-102. 

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