US Navy and Marine aviators have been using the Raytheon AIM-7 Sparrow and the AIM-120 advanced medium-range air-to-air missiles (AMRAAMs—as shown on the F/A-18C Hornet above) since their development in the 1980s. (Photo: US Navy)
An analysis of the main types and differences between Chinese, Russian and Western missiles
This article examines the main types of air-to-air missiles (AAMs) which govern air combat. Modern air combat is extremely dynamic, and the presence/absence of capable AAMs and the skills behind their employment can make a significant difference in deciding the outcome of an air battle. The main factors of AAMs that need to be considered are: weapon carriage capacity and the probability of kill (Pk). The Pk depends on several factors: the separation between the launch aircraft and the target aircraft; the speed, altitude and bearing/ aspect of the launch aircraft relative to the target aircraft; the counter measures employed by the target aircraft; the agility of the target aircraft and the capability of the AAM itself. The no-escape zone (NEZ) of an AAM is defined as the zone in which the missile has enough energy to intercept the target aircraft, irrespective of any evasive manoeuvres performed by the target aircraft. Specifically, there are three main types of air-to-air missiles. The first ones are “heat seeking” missiles, equipped with an infrared (IR) seeker that homes in on the heat generated by the engines of the aircraft and the friction between the skin of the aircraft and the surrounding air. Modern IR missiles are extremely agile and can even sustain turns of 50 g or more, have high off-boresight (HOBS) capability and can also be cued using helmet-mounted sights (HMS). HMS allows pilots to designate and lock the target aircraft by simply looking at them. The HOBS capability can be as high as 90 degrees, although missiles such as Israel’s Python 5 and European IRIS-T also authorise a full 360 degrees launch envelope. Modern iterations also feature an imaging infrared (IIR/I2R) seeker which are programmed to recognise the expected shape of target aircraft, thus making them more resistant to countermeasures. Some IR missiles also feature multi-band ultraviolet (UV) seekers which allows for better discrimination between target aircraft and flares. Some of them are capable of lock-on-after-launch (LOAL) engagements and can be used for targets directly behind the launch aircraft (known as over-theshoulder firing). Generally, these missiles are used for within visual range (WVR) engagements (or dogfighting), although France and Russia have also developed beyond visual range (BVR) IR homing missiles in the form of MBDA’s MICA and R-27T/ET. Most prominent missiles in this category include the Russian R-73, American AIM-9 Sidewinder and MBDA’s AIM-132 ASRAAM. Due to their passive nature, these missiles do not provide any indication on radar warning receiver (RWR) of the target aircraft, and their launch can only be detected either visually or with the help of missile approach warning system (MAWS). As such, WVR combat remains exceptionally dangerous. The second category of air-to-air missiles are semi-active radar-guided missiles. These missiles require the target aircraft to be illuminated and locked in single-targettrack (STT) or track-while-scan (TWS) mode by the launch aircraft’s radar and then the missile homes in on the radar energy reflected from the target aircraft. STT is a technique where the launch aircraft’s radar focuses all of its energy on the target in a narrow cone, thus providing the highest fidelity (resolution) tracking solution. However, this does not allow simultaneous tracking of other targets and if the target aircraft is equipped with a radar warning receiver (RWR), it will receive an indication that it is being locked. In TWS, the launch aircraft’s radar tracks multiple targets simultaneous, and consequently, allows for multiple simultaneous engagements. However, since multiple targets are tracked simultaneously, the track fidelity is lower and the RWR of the target aircraft may or may not give an indication that it is being locked. These missiles are cost-effective, as the use of a passive seeker in the missile is much easier and cheaper. The prominent examples of these types of missiles include the American AIM-7 Sparrow, Russian R-27R/ER and French Matra Super 530D. The third and most important category of air-to-air missiles is the active radarguided missiles. These missiles feature an onboard active radar seeker which guides the missile during the terminal phases of the missile’s flight profile. However, the missile’s active radar seeker is quite small when compared to the launch aircraft’s radar. Hence, the tracking range of the missile’s seeker is quite small and as such, the missile is guided by the radar of the launch aircraft before the missile goes “pitbull” (the informative call when missile’s seeker becomes active). Active radar homing airto- air missiles can also be launched in fully autonomous (fire and forget) mode without any targeting information and mid-course guidance from the launch aircraft’s radar, but this poses the risk of destroying friendly aircraft and other unintended targets, and a much lower Pk. These missiles can also be fired using targeting information and guidance from off-board sensors, via a datalink. The most prominent examples of these types of missiles include the American AIM-120 AMRAAM, Russian R-77, MBDA’s Meteor, Chinese PL-12 & PL-15 and Indian Astra.
A Chinese J-20 armed with PL-15 missiles (Photo: Wikipedia)
China
The Chinese have made remarkable progress in the domain of AAMs since the mid-2000s and this rapid pace of development has placed China among handful of nations with defence industrial base capable of producing such advanced AAMs. The People’s Liberation Army Air Force (PLAAF) and People’s Liberation Army Naval Air Force (PLANAF) has introduced two indigenous active radar-guided missiles, the PL-12 and the PL-15, and an indigenous short-range imaging-infrared missile, the PL-10. In 2015-16, the PL-10 entered into service. The PL-10 features an imaginginfrared (IIR) seeker, thrust vector control and can perform all-aspect shots at very high G-loadings. The PL-10 can be cued using a helmet-mounted sight (HMS) and has off-bore sight launch capability of 90 degrees, which makes it particularly lethal during dogfights. The PL-10 also features a laser proximity fuse and has lock-on-afterlaunch (LOAL) capability which enables engagements beyond the seeker acquisition range. It is also very possible that PL-10 possesses over-the-shoulder firing capability in lock-on-after-launch (LOAL) mode. The estimated effective range is between 30-40 km. In terms of performance, the PL-10 is comparable to the MBDA’s AIM-132 ASRAAM and has a superior kinematic performance when compared to the American AIM-9X Sidewinder.
Models of FC-31 and a PL-15E missile on display at Airshow China 2021 in Zhuhai (Photo: Global Times)
The PL-12 was China’s first indigenous active radar-guided missile and entered operational service in 2005. The PL-12 was developed to counter the American AIM-120 AMRAAM and the seeker was developed with Russian help on the basis of imported Russian R-77 seeker heads. In terms of performance, the PL-12 is comparable to the Russian R-77 or the American AIM-120C-4. The estimated maximum range is between 60-90 km, which is between that of AIM-120B and AIM-120C-5. The PL-12 has a dual-pulse rocket motor and a radio proximity fuse, which gives it a very decent NEZ. Newer versions of the PL-12 have also been developed with several modifications. These modifications include an anti-radiation seeker, better ECCM (electronic counter countermeasures) capabilities and improved datalinks for mid-course guidance. The PL-12C featured folding fins to allow for carriage in the internal weapons bay of Chengdu J-20. Ramjet propulsion, on the lines of MBDA’s Meteor active radarguided beyond visual range air-to-air missile (BVRAAM), was also tested on PL-12D. However, no evidence exists that these variants entered operational service, instead they were used to develop PL-12’s successor, the PL-15. The PL-12 was also exported under the designation SD-10A/B for use on the JF-17 Thunder’s of the Pakistan Air Force (PAF). The SD-10B has a much larger NEZ and better Pk and ECCM capability than SD-10A. The SD-10B is also reported to have an anti-radiation seeker for engagement of airborne early-warning (AEW) aircraft. The PL-12’s successor, the PL-15 also has a dual-pulse rocket motor and an AESA seeker, which provides it with a very potent ECCM capability. The AESA seeker allows for much faster detection and classification of aerial targets including LO and VLO designs, better detection ranges, enhanced resistance to countermeasures, LPI/LPD capabilities and improved reliability. China is one of the few nations to have used an AESA seeker on an AAM, with the only other confirmed use being on the Japanese AAM-4B AAM. The PL-15 also has cropped fins for carriage in the internal weapons bay of Chengdu J-20 and other future stealth combat jets of China. The PL-15’s maximum range is estimated to be around 200 km. As such, the PL-15 outranges the latest American AIM-120D AMRAAM. The maximum range of PL-15 is comparable to the MBDA’s Meteor BVRAAM, although Meteor retains significantly larger NEZ and a much higher Pk due to its ramjet propulsion. It is also believed that the PL- 15 features passive guidance and can receive targeting information and mid-course guidance from airborne early warning and control (AEW&C) platforms currently in service with the PLAAF. The PL-15 is expected to replace PL-12 as the standard BVR armament for PLAAF and PLANAF fleets in the future. The export variant of the PL-15, designated as PL-15E, has a maximum range of 145 km. The PL-15E is also scheduled to be integrated on to the JF-17 Thunder Block III’s of the Pakistan Air Force (PAF). PAF’s recently inducted Chengdu J-10CE are also confirmed to have been integrated with PL-15E. A very long-range AAM, known as PL-X or PL-17 is also under development in China. The maximum range is estimated to be around 400 km with a very high-altitude cruise phase. A lofted trajectory will also be used to minimise drag, in altitudes in excess of 30,000 meters. The missile is expected to feature a dual-mode guidance, with an active radar seeker and an IR-homing seeker. The dual-mode guidance will make the missile more resistant to countermeasures as well as improve target selection capability. The missile is 6 meters long and only has four cropped fins at the tail and no control surfaces at the mid body, suggesting that the design is optimised for stable flight trajectory and maximising range, and not high manoeuvrability. Given the large cross-section of the missile body, the radome could accommodate a large seeker that could have a detection range of 40-50 km or more against large radar cross-section (RCS) platforms such as refuelling tankers, airborne early-warning aircraft, ISTAR aircraft and other high value assets. In such very long-range engagement scenarios, the missile would also most likely receive targeting information and mid-course guidance from networked and third-party sensors. So far, only the Shenyang J-16 seems to be the launch platform of the missile due to its large dimensions.
A model of an export version of the PL-12, SD-10A, (bottom-left corner) with JF-17 on display at the Farnborough Airshow.
Russia
After the collapse of the Soviet Union, the development of air-to-air missiles suffered badly in Russia due to the dire state of the Russian economy and substantial cuts in defence R&D spending. Multiple projects were subsequently cancelled. However, Russia has now begun to bounce back and recapitalise on the development of air-to-air weapons. The primary short-range AAM in service with the Russian Aerospace Forces (VKS) is the infrared-homing R-73 (AA- 11 Archer), that entered service in 1984 and was widely regarded as a gamechanger due to its high off-bore sight (HOBS) capability of 40 degrees. The VKS has started receiving deliveries of an improved variant of R-73, designated as R-74M. Although the R-74M has better kinematic performance, range and HOBS capability (60 degrees) than R-73 and an improved seeker for target acquisition, the lack of a modern imaging IR/UV seeker makes it vulnerable to countermeasures such as flares and DIRCMs (directional infrared countermeasures). Russia has now switched its focus to the K-74M2, or Izdeliye 760 (the K prefix denotes a missile that is still in the development phase), which is optimised for carriage in the internal weapons bay of the Sukhoi Su-57. The K-74M2 is expected to feature an IIR seeker, and a rocket motor for increased burn time, for longer range. The K-74M2 can also be fired in lock-on-afterlaunch (LOAL) mode, which is typically required when launched from an internal weapons bay, as the missile begins its flight under inertial control before achieving an in-flight lock on the target. For BVR engagements, the mediumrange R-27 (AA-10 Alamo) was developed during the 1980s. The extended range variants of R-27, designated as R-27ET (IR-guided) and R-27ER (semi-active radar-radarguided) were also developed. The range is comparable to AIM-120B AMRAAM, but the energy loss at higher ranges is slightly higher due to the presence of larger control surfaces. Active radar homing versions of R-27, designated as R-27EA/EM, were also developed, but never entered operational service with the VKS.
RuAF Su-27 equipped with Kh-31, R-27, R-73 and R-77 missiles (Photo: NPO Saturn)
Russian Air Force Su-30SM along with R-27RE and R-73 missiles (Photo: Russian MoD)
Russian Air Force Su-30SM along with R-27RE missiles (Photo: Russian MoD)
The R-77, or Izdeliye (AA-12A Adder) medium-range active radar homing missile was also developed by Russia during the 1990s, but was never procured for the VKS. As such, it remained predominantly an export product, with India and China being the main export customers. An improved variant of the R-77, called R-77- 1, or Izdeliye 170-1 (AA-12B Adder) was finally introduced in service in 2015, with an upgraded seeker, improved resistance to countermeasures, aerodynamic refinements, longer range and improved shelf and carriage life. The R-77 and R-77-1 feature a unique lattice fin arrangement at the rear, which helps in maximising manoeuvrability, but also induces higher aerodynamic drag at longer ranges. The maximum range of R-77-1 is little more than 100 km, but has inferior performance when compared to the C-variants of AIM-120 AMRAAM at longer ranges. The R-77-1 was first operationally deployed in 2015 with the Sukhoi Su-35S in Syria. The K-77M, or Izdeliye 180, is the next stage in the development of the R-77. The K-77M features conventional fins instead of the lattice fin arrangement. This allows for internal carriage by Sukhoi Su-57 and also reduces aerodynamic drag and radar crosssection. Other changes include a new dual-pulse rocket motor and a further upgraded seeker. The dual-pulse rocket motor ensures an extended range, more thrust output during the missile’s flight profile and higher energy for terminal manoeuvres. Vympel, the missile’s manufacturer, has claimed that the K-77M will be superior to AIM-120C-7 AMRAAM, and comparable to subsequent AMRAAM developments – presumably, the AIM-120D AMRAAM. Vympel also claims that the K-77M is capable of engaging antiaircraft missiles fired at the launch aircraft, even missiles approaching from rear. As per unconfirmed reports, K-77M will have a range double of that of R-77. This would suggest a range of more than 160 km. A ramjet-powered variant of K-77M, designated as K-77ME, or Izdeliye 180-PD (the suffix PD stands for Priamotochnyi Dvigatel, or ramjet engine in Russian) is also speculated to be under development. This speculation stems from a video released by the Russian Ministry of Defence in which a Sukhoi Su-57 was seen carrying an air-to-air missile with an air intake (very possibly for the ramjet engine) on an external pylon. When it comes to very long-range engagement scenarios, Russia has developed the hypersonic R-37M, or Izdeliye 610M (AA-13 Axehead) active radar-guided airto- air missile. The R-37M is much larger, heavier and more expensive missile than specimens of the R-77 and R-27 family. The missile is estimated to have a range of more than 200 km, with the primary launch platforms being the Mikoyan MiG-31BM and Sukhoi Su-35S. As such, the weapon is expected to outrange MBDA’s Meteor and AIM-120D AMRAAM. The missile is intended for use against high value assets such as airborne early warning and control (AEW&C) aircraft, refuelling tankers, etc. The R-37M is the primary armament of Mikoyan MiG-31BM interceptor, and according to Russian media reports, it can be used to shoot down ballistic missiles and low-flying cruise missiles. The Sukhoi Su- 35S can carry a maximum of four R-37Ms; one under each wing and two underneath the fuselage. According to the missile’s manufacturer, the missile can engage “some types” of aerial targets at ranges of up to 124 miles. This suggests that only larger and probably less agile targets can be engaged at the limits of missile’s flight envelope. The missile is powered by a dual-pulse solid rocket motor. Also, as per the manufacturer, during the terminal phase of engagement, the seeker can lock on to a target with 54 square foot radar cross-section at ranges of 25 miles or more.
The West
Currently, the most potent air-to-air missile for beyond visual-range engagements of fighter-size targets in service anywhere in the world, is MBDA’s Meteor. The Meteor’s most impressive feature is its propulsion system. The Meteor uses a solid fuel, ducted ramjet engine, instead of the traditional rocket motor found on most air-to-air missiles. With its ramjet engine, the Meteor can throttle itself during different phases of the missile’s flight profile, whereas a traditional rocket engine delivers all of its energy in a continuous burn. A typical BVRAAM usually has a burn phase, in which due to the combustion of the propellant, the missile gains energy while usually climbing to a high altitude. This burn phase lasts only for a few seconds. The missile then glides on its built-up energy to its predicted impact point of the target aircraft and dives on to the target in the terminal attack phase with gravity on its side to maximise its ability to make hard manoeuvres. In case of the ramjet-powered Meteor, the engine can throttle itself during the cruise phase, and then in the terminal attack phase, the engine can throttle up again to maximise energy (around Mach 4.5) and make hard manoeuvres. This significantly increases the missile’s noescape zone (NEZ). As such, the missile’s manufacturer, MBDA claims Meteor has the longest NEZ among all the BVRAAMs in the world. The Meteor features an active X-band radar seeker and an impact and RF proximity fuse. The missile also has a two-way datalink and network centric capability. With its network centric capability, the Meteor can receive targeting information and telemetry updates from third-party sensors, including other fighters, airborne early warning and control (AEW&C) aircraft, land-based radars, etc. The two-way datalink capability allows the pilot to re-target the missile after it has been launched. The missile also transmits back its state parameters such as fuel and position back to the launch aircraft in realtime. The two-way datalink also ensures a hit/kill assessment, better ECM resistance and better guidance since the launch aircraft’s mission computers can know the exact position of the missile instead of calculating where it probably is. The two-day datalink is fully operational on the Eurofighter Typhoon and Saab Gripen. The most popular beyond visualrange air-to-air missile (BVRAAM) is the American AIM-120 AMRAAM, built by the US-based Raytheon. Its latest iteration, the AIM-120D AMRAAM, is powered by a dual-pulse solid rocket motor, features a highly jam-resistant RF seeker, and a twoway datalink. The AIM-120D AMRAAM also has third-party targeting capabilities like the Meteor and boasts an additional 50% range over its previous version, the AIM-120C-7 AMRAAM. The maximum range for the D-model is estimated to be around 160-170 km. The AIM-120D AMRAAM is also speculated to have an AESA seeker, though it is not confirmed.
MBDA Meteor on German Air Force Eurofighter Typhoon (Photo: MBDA)
Despite its proven record, the AIM- 120 AMRAAM is finally showing its age, and is slowly being outperformed by its Chinese rivals. As such, the US has awarded Lockheed Martin to develop AMRAAM’s successor, the highly secretive AIM-260 JATM (Joint Air Tactical Missile). The United States Air Force (USAF) has publicly stated that the development of the Chinese PL-15 is one of the primary reasons behind the initiation of the AIM-260 JATM programme. The AIM-260 JATM is expected to have the same dimensions, the length and the diameter as the AIM-120 AMRAAM, probably to accommodate the weapon in the internal weapon bays of the stealth fighters, the F-22 and F-35 of the US. These dimensional requirements rule out the possibility of ramjet propulsion, and hints at the possibility of a dual-pulse rocket motor with better higher energy density propellant. Given the extreme secrecy the JATM programme is wrapped around, the missile may also very likely feature an AESA seeker, two-way datalink and thirdparty targeting capabilities. The possibility of dual-mode seeker, radar and imaging infrared (IIR) also cannot be ignored. Majority of the details about the AIM-260 JATM remains classified, but it confirmed that the Pentagon aims the missile to achieve initial operating capability (IOC) in 2022. Apart from the AIM-260 JATM, the US-based Raytheon is also developing a long-range air-to-air missile, known as the Long-Range Engagement Weapon (LREW). Again, the LREW programme is extremely classified. This munition is expected to be a two-stage missile. This speculation emerges from the fact that the official concept art of the programme depicts a two-stage missile being launched from the internal weapons bay of an F-22. Raytheon is presently also developing a new medium-range missile, known as Peregrine for use against drones, manned aircraft and cruise missiles. Raytheon plans to offer Peregrine missile as a complement to the AIM-120 AMRAAM and the AIM-9X Sidewinder, both of which are manufactured by Raytheon. Raytheon has stated that Peregrine will have the range of an AMRAAM and the manoeuvrability of a Sidewinder, and a length of six feet and weight of 150 pounds. But, since different variants of AMRAAM have different ranges, it is unclear which one Raytheon has referenced for comparison. To put things into perspective, the AMRAAM has a length of 12 feet and a weight of 345 pounds. This could effectively double the number of air-toair munitions carried internally by the F-22 and F-35 in their stealthy configurations. Raytheon has also stated that the missile will feature a multi-mode seeker, including an imaging-infrared and a blast fragmentation warhead. The most likely option would be the combination of the radar seeker of AIM- 120 AMRAAM and imaging-infrared seeker of AIM-9X Sidewinder. The multi-mode seeker will make the missile highly resistant to electronic jamming, as the missile can switch to infrared guidance. In case countermeasures are employed to blind the missile’s infrared seeker, the missile can revert back to radar guidance. The missile’s physical models presented by Raytheon almost certainly confirm an advanced rocket motor for propulsion. This is likely to contain a high energy density propellant and multi-pulse rocket motor. Currently, the Peregrine is an internally-funded project of Raytheon.
An F-35 fires an AMRAAM (Photo: Raytheon)
An AMRAAM F3R missile is launched from an F/A-18F during a test (Photo: Raytheon)
Raytheon’s Peregrine. (Image: Raytheon)
Article by Pushpan
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