The design of the MiG-25 was directed entirely at achieving high speed and high altitude.
Conceived to intercept the North American B-70 Valkyrie Mach 3 Bomber, the Mikoyan-Gurevich MiG-25 (NATO reporting name: Foxbat) supersonic interceptor is still among the fastest military aircraft to have ever entered service. It was the last plane designed by Mikhail Gurevich before his retirement.
It is interesting to see how the F-15 (and indeed all fighters of that time period) were influenced by the MiG-25. It’s appearance at Soviet airshows and flypasts on May Day parades was impressive, and the Soviets made frightening claims as to its performance, claims which could not be independently verified. The F-15 Eagle, was designed with countering the claimed performance of the MiG-25. Western examination of the MiG-25 did not occur until a MiG-25 pilot defected and landed in Japan, after the F-15 was already in production. In reality, the MiG-25 was a purpose built interceptor with a very narrow niche role, while the F-15 was designed to be a powerful, all-weather, extremely maneuverable, tactical fighter aimed to permit the US Air Force (USAF) to gain and maintain air supremacy over the battlefield.
Still, although it was more advanced than the Foxbat, the F-15 was never as fast as the MiG-25.
‘Simple, really: the MiG-25 HAD to be fast. It was meant to intercept one of the fastest aircraft ever conceived – what would eventually become the B-70 strategic bomber, capable of sustained Mach 3 flight,’ explains Jure Trnovec, an aviation expert, on Quora.
‘For that to happen, it had to be able to go just as fast, if not faster, and carry a large radar to guide its missiles. Since the Soviets haven’t really mastered working with titanium at that time (not to mention it was eye-wateringly expensive), and aluminium was not quite heat-resistant enough for Mach 3 flight, it was made out of steel, which is quite heavy, but it compensated for that with engines of simply ridiculous size.
‘Even though those engines would be shot after flying at Mach 3, it didn’t matter to the Soviets, as long as they stopped the nuclear-armed bombers that were threatening their homeland.’
‘As it was so beautifully narrated by Peter Ustinov in what was perhaps one of the best documentaries in Discovery’s great Wings series (Remember the time when Discovery actually made content worth watching? Good times.) :
‘“The design of the MiG-25 was directed entirely at achieving high speed and high altitude. It was not meant to be maneuverable. It was not meant to have good low speed performance. It was simply meant to travel through the air as fast as Soviet ingenuity could make it go.”’