IMINT & Analysis: Beyond BVR: Russia's R-37 and KS-172 LRAAMs
With the current developments in super agility, and the ruthless performance of today’s WVR air-to-air missiles such as the Israeli Python 4, it is no surprise that most fighters have adopted BVR weapons as their primary air-to-air armament. The last true Western Big Stick in the air-to-air arena was the US Navy’s AIM-54 Phoenix, with its 100+ NM range and active radar seeker. The LRAAM project of the Mid-1980’s, charged with producing a successor to the AIM-54, would have given the US Navy an even greater capability well into the 21st Century. However, the project was terminated, leaving the medium-range missile as the primary air-to-air weapon in the BVR arena in the West, until the European Meteor and the American AIM-120D are introduced.
The primary purpose of the AIM-54 was to defend carrier battle groups at long range from attack by Soviet bombers and their cruise missiles. This reason, coupled with the fact that the AIM-7 (and later the AIM-120) was regarded as more than capable of countering the Soviet fighter threat, explains why the USAF never took it upon itself to develop its own long-range weapon or adopt the AIM-54 for its own use (although the F-14/AIM-54 combination was briefly considered, as well as an AIM-54 armed F-15). Russia’s premier long-range AAM, the R-33, was designed with a similar purpose in mind. The MiG-31/R-33 combination was designed to counter the threat of Western air-launched cruise missiles, specifically the AGM-86B, and their launchers. Now, however, Russian weapon designers are exploring new tasks and capabilities for the next generation of LRAAMs.
LRAAMs are limited in their usefulness. A large weapon such as the AIM-54 or R-33 would have a difficult time against a modern, agile fighter such as the Su-27 or F-16. To understand this, one needs only to examine the flight profile of the AIM-54. The Phoenix achieves its extremely long range by using a substantial boost motor, propelling it to heights in excess of 100,000 feet and speeds greater than Mach 6. The missile then nosedives towards its target, activates its seeker when within range, and makes the intercept. But what happens when one of these weapons is employed against a maneuvering target? A long-range missile expends most of its kinetic energy during the boost phase of its flight, leaving it very little with which to maneuver against an agile target. This is part of the reason behind the failure of the AIM-54 to score an air-to-air kill in DESERT STORM: the AIM-54 was never designed to be employed in such a manner. One solution would be to fire the weapon at a shorter range, but then you are better off using a dedicated MRAAM such as the AIM-120; large, heavy weapons in the AIM-54 class are typically not as maneuverable as smaller, lighter MRAAMs. LRAAMs are more adept at engaging non-maneuverable targets, such as lumbering bombers, and cruise missiles, which for the most part fly straight courses, making course corrections as dictated by their guidance systems. Granted, ramjet propulsion and gel-fueled rocket engines can now give MRAAMs ranges touching 60 or even 100 nautical miles, pushing them into the LRAAM class. This is where the capabilities of Russia’s new LRAAMs become even more impressive.
The first new LRAAM to emerge from behind the former Iron Curtain is the Vympel design bureau R-37. This successor to the R-33 features a dual mode 9B-1388 active/semi-active seeker head and can reach ranges touching 160 NM, demonstrated in an October 1993 test launch from a MiG-31M, the weapons intended launcher aircraft. This was such an accomplishment, especially in the former Soviet Union, that in April of 1994 Boris Yeltsin sent telegrams to the OKBs (design bureaus) involved congratulating them on this achievement. The weapon is matched to the improved Zaslon-M radar of the MiG-31M, which can accommodate six of these advanced weapons under its fuselage, replacing the baseline MiG-31’s four R-33s. The R-37 retains the basic aerodynamic arrangement of the older R-33, with a few notable differences. The control surfaces have been reshaped, to provide the weapon with better agility, and the rear control fins have been moved further aft, leaving a noticeable gap between these fins and the missile’s wings. The R-37’s nose has also been reshaped, no doubt due to the new seeker head. Semi-conformal carriage is still achieved by folding the rear fins, as in the R-33. Still touted as primarily an anti-cruise missile weapon, the R-37 is slated to be incorporated into the upgraded MiG-31BM at a future date, possibly in the form of the further improved K-37M variant (Note: In-service Russian AAM designations begin with R, test weapons or weapons still in the prototype stage have designations beginning with K.). Baseline R-37s may also arm improved MiG-29SMTs in the Russian Air Force, although this is unlikely as even an upgraded FULCRUM lacks the radar needed to fully take advantage of the R-37’s impressive intercept range.
On the surface the R-37 appears to offer only technical improvements over the R-33. The advantages it will bestow upon the MiG-31, however, are more than just longer reach. A longer ranged AAM will give the MiG-31 the capability to engage targets at greater ranges, giving it more time to reacquire and reengage targets which have gotten past the first wave of weapons. In theory this will increase the effectiveness of the MiG-31, meaning fewer aircraft will be needed to fulfill the same role. Given the current financial state of the Russian military, this will obviously be very beneficial.
The second LRAAM to emerge from Russian armament designers is the little known Novator KS-172, also referred to as the AAM-L. This weapon has been seen in armament displays accompanying Su-35 aircraft and has recently been displayed as the improved KS-172S-1 under the wing of an improved Su-35BM FLANKER variant. The AAM-L has an entirely different purpose than the R-37. Novator has designed a very long-range weapon intended to specifically attack AWACS aircraft equipping hostile nations. Where the R-37 retains a complex arrangement of control surfaces, the AAM-L is almost barren. The weapon resembles a typical surface-to-air missile, such as the 48N6 (S-300PMU-1/2), possessing only small control fins at the rear of a long, pointed body. The active radar homing missile is reported to have a range touching 216 nautical miles, which can be extended with the addition of a booster stage. Long range is a must for a weapon intended to target aircraft such as the E-3; this keeps the launching aircraft out of range of the weapons employed by escorting fighter aircraft.
It is no hidden fact that much of the success of Western militaries comes from the battlefield information superiority bestowed upon them by modern airborne sensor platforms. AWACS aircraft such as the IAI Phalcon and E-3 Sentry give commanders an unrivalled picture of the airborne arena and provide pilots with unparalleled situational awareness. The J-STARS platform provides commanders with a comprehensive view of the battlefield, allowing them to redirect and reposition forces to counter and defeat an opposing army. Winning a war against a Western military force armed with this knowledge proves a daunting task, as demonstrated by the rout of the Iraqi military in 1991. To put it another way, the 21st Century war is a digital encounter, and successfully engaging an enemy armed with these information resources would prove difficult to even the most well-equipped military. The AAM-L is intended to deny an enemy access to this wealth of knowledge, hopefully giving the Russian military the edge needed to prevail in a conflict.
Military weapon development progresses as follows: a threat is identified, a counter is developed, and the counter is deployed. In the case of Russia’s LRAAMs, the threat was identified as cruise missiles and AWACS aircraft. The counters developed were the R-37 and AAM-L LRAAMs. Although they have yet to be fielded by the Russian Air Force, the existence of weapons in this class is enough to cause Western designers to consider new approaches to aircraft and missile design, most notably in the form of stealth technology. Quite a few of the designs for US Navy and Royal Navy future carrier based AWACS platforms have already been seen to incorporate stealth technology. Of course, one can assume that this will only cause the Russians to develop further advanced weapons and countertactics; and the circle continues. One thing is for certain: the technology exists to deny an enemy the ability to use advanced sensor platforms and rely on cruise missile attacks. Perhaps in a future conflict the ability to overcome these losses will be how military capabilities are analyzed.
