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The XB-70 Valkyrie
The futuristic XB-70 was originally conceived in the 1950s as a high-altitude, nuclear strike bomber that could fly at Mach 3 (three times the speed of sound) — any potential enemy would have been unable to defend against such a bomber.
Triggered by concerns over the emerging XB-70 in the United States, the Soviets started the development of the Tupolev Tu-135 Mach 3 bomber.
The Tupolev Tu-135
As explained by David Baker in his book Russian Bombers, design work was led by S. M. Egera but in 1962 the Myasishchev design leader L. L. Selvakovka was transferred to Tupolev, bringing knowledge and experience from the M-50 to the M-57 projects. A wide range of engines were selected as optional for the Tu-135 and even a nuclear plant was considered, albeit only briefly.
In general, driven by the thrust of each type, four to six engines were planned in a wide-range of configurations. A variety of wing arrangements were examined before double-delta wing with variable sweep on the leading edge was chosen. There would be a single tail fin and twin engine nacelles on underwing pods. There was provision for a wide range of cruise and gravity bombs, both conventional and nuclear.
Duralumin was to be widely used in the airframe with thermal protection an essential prerequisite for the skin; heat-resistant alloys and special materials being evaluated. The definitive design utilized NC-6 turbofan engines, with which the Tu-135 was calculated to achieve 3,000km/h (1,864mph). Some 10-20% of the flight distance could be conducted at Mach 2.82, a speed determined by the temperature limits on usable materials.
Destroying aircraft carrier
Its mission was to destroy aircraft carriers and large surface battle fleets as well as attacking harbours and logistical supply ports with cruise missiles, some of which would have a range of 500km (311 miles). For that it needed a range of 5,000km (3,108 miles).
The Tu-135 was also required to loiter on patrol for up to eight hours, 2,000km (1,243 miles) from base. On top of which it was required to operate from unpaved strips and low-grade runways. But the Tu-135 was also to carry air-to-air missiles for attacking enemy air transport and resupply aircraft, to harass logistical routes and to attack small, heavily defended strategic targets with cruise-type weapons or air-launch ballistic rockets. The Tu-135P reconnaissance version was expected to swap offensive equipment for optical and sensor packages, making it capable of electronic intelligence gathering and mapping.
Always with one eye on progress with the XB-70 Valkyrie, tweaks and changes to the design were a constant strain on finding a truly definitive configuration, dozens of different shapes and sizes being proposed.
By the early 1960s, however, new Surface-to-Air Missiles (SAMs) threatened the survivability of high-speed, high-altitude bombers. Less costly, nuclear-armed ICBMs (Intercontinental Ballistic Missiles) were also entering service. As a result, in 1961, the expensive B-70 bomber program was canceled before any Valkyries had been completed or flown.
By contrast the Soviets continued to look for a Mach 3 bomber: in fact, even though the Tu-135 project was suspended, the development of the Sukhoi T-4 was initiated.
Russian Bombers is published by Mortons Books and is available to order here.
Photo credit: Yefim Gordon via Tony Buttler via Mortons Books
