R-37 (missile)

The Vympel R-37 (NATO reporting name: AA-13 Axehead)^[2] is a Russian long-range air-to-air missile. The missile and its variants also had the names K-37, izdeliye 610 and RVV-BD (Ракета Воздух-Воздух Большой Дальности (Raketa Vozduh-Vozduh Bolshoy Dalnosti), "Long range air-to-air rocket"), and the NATO codenames "Axehead" and "Andi".^[3] It was developed from the R-33.

Vympel R-37M NATO reporting name: AA-13 Axehead
R-37M (under the export designation RVV-BD) at 2013 MAKS Airshow
Type	Long-range air-to-air missile
Place of origin	Russia
Service history
In service	2019–present
Used by	Russian Aerospace Forces
Production history
Designer	Tactical Missiles Corporation
Designed	1980s
Manufacturer	Vympel MKB
Produced	1985
Variants	R-37M (export: RVV-BD)
Specifications (RVV-BD)
Mass	510 kilograms (1,120 lb)
Length	4.06 metres (13 ft 4 in)
Diameter	38 centimetres (15 in)
Wingspan	72 centimetres (28 in)
Warhead	HE, fragmentation
Warhead weight	60 kg (135 lb), conventional or thermonuclear[1]
Propellant	Boost-Sustain Solid Rocket
Operational range	150–400 km (93–249 mi) [2] Up to 200 kilometres (120 mi) (RVV-BD)
Maximum speed	Mach 6 (7,400 km/h; 4,600 mph)
Guidance system	Inertial with mid-course update, semi-active and active radar homing
Launch platform	MiG-31, Su-35S, Su-57

It is designed to shoot down tankers, AWACS and other C4ISTAR aircraft^[4] while keeping the launch platform out of range of any fighters that might be protecting the target.

According to Janes there are two variants, the R-37 and the R-37M; the latter conceived as having a jettisonable rocket booster that increases the range to "300–400 km" (160–220 nm).^[3] In 2023, Rosoboronexport introduced the export version of the R-37M, designated RVV-BD. It has a launch range of up to 200 kilometres (120 mi; 110 nmi) and maximum altitude of 25 kilometres (82,000 ft) with a 60 kilograms (130 lb) warhead. The missile is compatible with Sukhoi Su-57, Sukhoi Su-30, Sukhoi Su-35, Mikoyan MiG-31BM and Mikoyan MiG-35.^[5][6]

Design

The R-37 was developed from the R-33. For compatibility with aircraft that did not have the MiG-31's sophisticated radar, the semi-active seeker was replaced with a variant of the Agat 9B-1388 active seeker.^[2] Similarly, folding tail controls allow semi-conformal carriage^[2] on planes that are not as big as the MiG-31.

Mid-body strakes enhance lift^[2] and hence increase range. According to Defence Today, the range depends on the flight profile, from 80 nautical miles (150 km) for a direct shot^[2] to 215 nautical miles (398 km) for a cruise glide profile.^[2]

The R-37M designation has since been used for a modernized variant of the missile, also known as RVV-BD (Raketa Vozduh-Vozduh Bolshoy Dalnosty, or Long-Range Air-to-Air Missile). R-37M's range exceeds 200 km, and it is capable of hypersonic speeds (~Mach 5).^[7] It will be carried by the modernized MiG-31BM interceptors and Su-35S and Su-57 multirole fighters.^[8]

A further derivative designed for internal carriage in the Su-57, designated as Izdeliye 810, has folding rear fins, shorter strakes, and updated seeker and motor.^[9]

The missile can attack targets at altitudes of 15–25 kilometres (49,000–82,000 ft), guided semi-actively or actively through the Agat 9B-1388 system.^[10]

History

The missile was designed in the early 1980s and first flown in 1989.^[3] Testing of the R-37 continued through the 1990s,^[3] and in 1994, a trial round scored a kill at a range of 162 nautical miles (300 km).^[2] However, the program appears to have been dropped around 1998 on grounds of cost.^[3] Work on the missile appears to have restarted in late 2006,^[3] as part of the MiG-31BM program to update the Foxhound with a new radar and ground attack capability.^[3]

In 2018, the R-37M had finished its operational validation tests.^[11][12] Zvezda TV reports have recorded the Su-35 carrying the R-37, apparently as part of an air combat loadout. In this configuration, the craft carries two R-73s in the central wing pylon, two R-77s slung underneath the engine nacelles, and two R-37s on the hardpoints between the engines, with an option to carry a few more missiles, such as a Kh-31 anti-radiation missile.

The US Defense Intelligence Agency revealed in a 2025 report that Russia is fielding a nuclear-armed air-to-air missile. While the report does not mention any specific missile, analysts believe that it refers to a nuclear-capable variant of the R-37M missile.^[13]

Operational history

The R-37M has, since October 2022, been the main threat against the Ukrainian Air Force. During the 2022 Russian invasion of Ukraine, MiG-31 aircraft have reportedly shot down several Ukrainian aircraft, mainly by using the long range R-37.^[14] By remaining at high speed and high altitude, MiG-31s have been able to operate virtually unopposed due to Ukrainian fighters lacking range, speed, or altitude necessary to engage the MiG-31.^[15][16] The Ukrainian Air Force lacked fire and forget missiles until the introduction of the AMRAAM and MICA. They relied on the R-27 missiles, both the R-27R and R-27ER. The Ukrainian pilot must illuminate the Russian aircraft with their radar to guide the missile to the target. Russian pilots firing active radar, fire and forget, R-77 give the Russian pilots the ability to launch their missiles and then take evasive action. Ukrainian pilots were forced to "exploit ground clutter and terrain-masking to get close enough to fire before being engaged".

A report by the Royal United Services Institute (RUSI) states that in October some six R-37Ms were being fired at the Ukrainian Air Force a day. The Su-35S is also used as a carrier for the R-37M. Four MiG-31 were also deployed to Crimea at the Belbek Air Base in mid 2022.^[17]

In August 2022, Russian forces maintained a Combat Air Patrol of either a pair of Su-35S or MiG-31s on station to shoot down Ukrainian aircraft. The RUSI stated: "The VKS has been firing up to six R-37Ms per day during October. The extremely high speed of the weapon, coupled with very long effective range and a seeker designed for engaging low-altitude targets, makes it particularly difficult to evade."^{[17][18][19][20][21]}

In February 2023, Ukraine obtained wreckage of a R-37M which would be of interest to Ukraine and Western countries.^[22][23]

According to a Russian source, the missile is carried by the Su-35S and Su-57 fighters, and the MiG-31BM interceptor.^[24]

According to Ukrainian pilots, the R-37M isn't achieving a lot of "hard kills", the destruction of actual Ukrainian aircraft. However, their launch forces pilots to abandon their current mission and take evasive action.^[25] Ukrainian pilots believe that the only defence is for their allies to supply them with F-16 fighter jets and AIM-120 AMRAAM missiles. While it won't close the distance, Ukrainian pilots hope that it will push back the effective range of missiles like the R-37.^[26] However according to a Ukrainian official, Ukraine is looking for opportunities to modernize the F-16 Block 20 MLU fighter jets planned for transfer. Early generation AN/APG-66 radars of older F-16 Block 20 MLU only have similar range to Ukrainian Mig-29s and possess no significant advantage compared to current Ukrainian fighters and both are inferior to the radar of current Russian fighters used in the war such as Irbis-E and N110M Bars-M.^[27][28][29]

See also

• AIM-54 Phoenix – (United States)
• AIM-152 AAAM – (United States)
• AIM-174B ERAM – (United States)
• AIM-260 JATM – (United States)
• Novator KS-172 – (Russia)
• PL-21 – (China)
• PL-17 – (China)
• Long-Range Engagement Weapon – (United States)
• Meteor – (France, United Kingdom, Italy, Germany, Spain, Sweden)
• Astra Mark 3 – (India)

Gallery

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  RVV-BD
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  RVV-BD