In the Cold War, the Russian MiG-31 codenamed 'Foxhound' was the fastest and most potent interceptor fighter in the Soviet Air force. The power of the Foxhound is expressed by the sheer power its jets can drive hard into American bombers if there was a war, but it never demonstrated that capability.
It was built to satisfy the requirement for a heavy interceptor that could defend the borders of the USSR when it still was not dismembered. The Soviet Union's Air Defense Forces (VPVO) had light fighters which lacked the Foxhound's attributes.
The range required and great speed bring the plane to bear on slower US Air Force bombers, which would pass the arctic to transit into the Russian homeland.
Special aircraft like a Russian 'Blackbird'
Speediness led to the design of fast aircraft that would rival the 5th generation fighters. Soviets built the Tupolev Tu-28 and Tu-128 as the initial design for a Russian interceptor, constructed to be heavy planes to carry ordnance, capable of sustaining incredible speeds, and faster than other planes existing in Russia, reported the Nationalist Interest.
The Tupolev by the 60s were woefully obsolete when the B-58 Hustler was way faster than it. But, the MiG 25 code-named Foxbat is being developed. It would be the Kremlin's solution for a fast interceptor.
Monstrous was not enough to describe its R-40 air to air missiles when it zoomed to the borders. Versatile it was as a photo recon plane, and the Soviet Air Force(VVS) even had a dedicated strike plane.
Not satisfied, the Soviets in the '80s upped the ante with the MiG-31 Foxhound, making it a better plane.
The Russians added one more crewman, the weapons systems officer, on all the variants with updated flight performance, improved radar, and weapons equipment.
At some point, it carried a gun for close-in dogfights but was removed since it was an interceptor relying on missiles for distant shootdowns of targets like the F-14 Tomcat with the Phoenix missile.
The Foxhound is still active service with the Russian. Expect it to fly into the 2030s as a capable legacy aircraft.
To keep it current is a mid-life upgrade into the MiG-31BSM cited Airforce Technology, which includes new strike weapons and modernized avionic. MiG-31 was chosen to load the Kinzhal hypersonic missile, the new arsenal touted by Putin.
New generation interceptor
In August 2018, there was a notice that the upgraded MiG-31BSM will be replaced by the PAK DP or Prospective Aviation Complex Long-range Interceptor, noted Military Today. No matter what, Russia will require such a plane in any era.
The specialized interceptors can be done by the PAK-FA/Su-57 fighter, like its Foxhound ascendant. Checkmate has high-tech radar and can hit Mach 1+ with supercruise that doesn't need afterburners, with extra range air to air missiles.
Compared to the Foxhound, it has less range, but aerial tankers will extend operational distance significantly. Even with Su-27P Flanker, the Su-57 is still considered vital.
Many changes have happened to the Soviet's aircraft inventory, but the MiG-31 Foxhound stands apart with its speed. The Blackbird is gone, but the Foxhound is still in service.