As the Cold War built towards its climax, both the United States and the Soviet Union were competing not just to accumulate nuclear weapons. They were competing to build planes on which to deliver those weapons more quickly, further, and better than ever before.
From the fierce competition emerged two of the most ambitious bomber projects of the time: the Soviet Sukhoi T-4 Sotka and America’s XB-70 Valkyrie. Both of these technologies stretched the boundaries of engineering, but both were ultimately victims of changing strategy and technological developments.
The Valkyrie would be a bomber so fast and so high-flying that it would be out of range. Designed to cruise at Mach 3, flying at heights considerably above 20,000 meters, it would outrun any interceptor and penetrate ground defenses. Intercepted at such speeds, it would be almost impossible to intercept without complete coordination.
The Soviets replied in kind, creating interceptors such as the MiG-25 and MiG-31—planes capable of firing missiles on short-order contacts at high altitude—and testing their S-200 surface-to-air missile defense systems to the breaking point.
Despite all its intelligence, the Valkyrie had one deadly flaw: it was designed for a world that no longer existed. Its sole regard for speed and height was at the cost of maneuverability. The bomber was far too expensive, flew in a predictable line, and was rapidly becoming outdated against mobile ballistic missiles.
Missiles, as compared to bombers, could travel farther, hit sooner, and were effectively untargettable once launched. By the late 1960s, they had overhauled the entire strategic landscape.
The T-4 Sotka was, however, also the result of the same consideration that went into the XB-70: a Mach 3 bomber would require a certain configuration, rare materials, and very advanced systems. With its central frame made of stainless steel and titanium, it pushed Soviet aviation to new extremes, resulting in hundreds of patents and new technologies such as fly-by-wire control.
Its characteristic sagging nose, later copied by the Concorde, assisted pilots to take off and land, but in flight, they had to fly mostly on instruments and a periscope.
But for all the promise, the Sotka never achieved its target. Test flights barely hit Mach 1.3, still below the target design. The cost spiralled out of control, the technical problems mounted, and priorities were moved to more practical programs. The program was abandoned after just ten flights, although ideas were incorporated into bombers such as the Tu-22M and the Tu-160.
In time, Sotka and Valkyrie were displaced by new war realities. Ballistic missiles launched from mobile platforms cost less, were faster, and were more destructive to defend against than even the most sophisticated bombers. The coming of reconnaissance satellites changed the mathematics further, allowing each to obtain unrestricted sight of the other’s forces and removing surprise as an element. And with that openness, a new basis for arms control and stability.
Neither plane became the norm of its country’s nuclear arsenal, but both left lasting legacies. They demonstrated what could be accomplished at the limits of flight and set a precedent for subsequent planes such as the B-1 Lancer and the Tu-160, which balanced high performance with more flexibility. Their tale reminds us that no matter how sophisticated an armament appears, tactics and technology advance rapidly—and in the end, flexibility is worth more than brute speed or altitude.