A MiG-31 of the Russian Air Force.
Wikimedia Commons
According to a Ukrainian pilot, Ukrainian Air Force pilots have devised methods to evade the Russian Air Force’s long-flying Vympel R-37M air-to-air missiles.
“We have developed various tactics to evade this missile – and that’s why it’s not so successful against our jets,” Ukrainian Mikoyan MiG-29 pilot Juice told Lithuanian broadcaster Delfi.
According to Juice, the R-37M doesn’t get many hard kills. But it is forcing Ukrainian pilots to deviate from their planned flight paths to conduct evasive maneuvers.
That could count as a “soft kill.” Even if it doesn’t shoot them down, the R-37M could prevent Ukrainian pilots from completing their missions.
It’s no secret that the Russian Air Force has not achieved air superiority in the skies over Ukraine. Paralyzed by inflexible procedures, a desperate shortage of precision weapons, and battered by rigid Ukrainian air defenses, the Russian Air Force is at best holding its own, despite a 10-to-1 numerical advantage in fighters and attack jets over the Ukrainian Air Force.
The three regiments flying the Russian Air Force’s best interceptor – the twin-engine, two-seat Mikoyan MiG-31BM – are the rare winners. MiG-31 crews, flying high-altitude defense patrols along the ever-changing front lines and firing the powerful R-37M, have reportedly shot down several Ukrainian jets.
Russian defensive patrols “have proven extremely effective against Ukrainian attack aircraft and fighters, with the MiG-31BM and R-37M long-range air-to-air missiles being particularly problematic,” wrote Justin Bronk, Nick Reynolds and Jack Watling in a study for the Royal United Services Institute in London.
The MiG-31 flies higher, faster and further than the Ukrainian Air Force’s best Sukhoi Su-27 interceptors. The Russian heavy fighter can fly up to 60,000 feet up to 450 miles and zoom at Mach 2.5 for short periods.
From their high altitude position, MiG-31 crews can use the jet’s Zaslon radar to search for targets and launch a single R-37M under the belly at targets up to 200 miles away, although the missile at a range of not more than 80 miles works best. In contrast, a Ukrainian Su-27 cannot launch a Vympel R-27 missile further than 50 miles.
“The VKS fired up to six R-37Ms per day in October,” Bronk, Reynolds, and Watling wrote, “and the weapon’s extremely high velocity, coupled with a very long effective range and a seeker suitable for use in low Targets are designed high, making them particularly difficult to dodge.”
But not impossible to escape. Juice didn’t explain how Ukrainian pilots dodge R-37M shots, but one can guess.
On very long range shots in excess of 80 miles, a MiG-31 crew will detect a target with their own radar and fire the R-37M in the target’s direction. The missile instantly becomes ballistic before plummeting at six times the speed of sound.
For shots within 80 miles, the missile flies a flatter trajectory at a slightly slower speed. In any case, at a distance of no more than 20 miles from its target, the missile turns on its own radar seeker and sets itself up.
But it is possible to manipulate the 9B-1103M-15 viewfinder on board the R-37M. The 9B-1103M-15, like many modern radars, works by interpreting the Doppler shift of radar energy bouncing between the radar and a target.
To understand Doppler shift, imagine a spring. Compress the spring and its coils will come closer. Stretch the spring and the coils are further apart. Doppler shift is the movement of the “coils” of electromagnetic energy between a radar and a target.
In order not to clutter a pilot’s screen, a Doppler radar has a “speed gate”. It ignores slow-moving or stationary objects like trees and buildings. To get off the Doppler radar, you could try slowing down your speed relative to the radar.
For a fighter pilot, that means flipping upside down, pulling the stick back hard, and diving. Drop some radar foiling chaff to be safe, and you might just trick the incoming missile. “Notching” is the technical term for this tactic.
Notching is a tried and true technique for dodging long-range missiles. It works best when the evasive pilot has some altitude to spare. Diving to notch may not always be feasible for Ukrainian pilots, who often fly at low altitudes to avoid Russia’s ground-based air defenses. A vertical rotation is a possible substitute.
But notching only works if you know the rocket is arriving. A Ukrainian pilot’s radar warning receiver should pick up the R-37M’s seeker as soon as that seeker is activated, about 20 miles away. That should give the Ukrainian a few seconds to dive or turn around.
If the pilot doesn’t pay attention to his RWR, he won’t have time to maneuver. “If you are unaware of the launch of that missile, you are dead,” Juice said.
One can imagine Russian MiG-31 crews patrolling the Russian-Ukrainian border, dropping R-37Ms at any Ukrainian jets they spot. Just as well imagine Ukrainian crews diving or turning to avoid most missiles.
Even if the R-37Ms miss, all that hard maneuvering still has the effect of disrupting Ukrainian missions. “Sometimes we’re forced to stop our offensive missions,” Juice said.