Tu-131 Credit - © Mark Wade

Tupolev design for a long-range air-breathing surface-to-air missile. Never got beyond the design stage.

Tupolev's OKB-16 became involved in surface-to-air missile design at the end of the 1950's with the Tu-131 project, also designated '131' or 'Z' (for Zenith). This was to be an unmanned long range interceptor, equivalent to the American Bomarc. The two stage surface-to-air missile,'s cruise stage was to be powered by one or two Bondaryuk ramjets. The design, and the cometing MiG P-500, never got beyond the project design stage. The missile would have been 9.6 m long, with the cruise stage having a length of 7 m. The vertical fins were canted at a sixty degree angle. Total launch mass was 2960 kg, with the cruise stage weighing in at 1460 kg including the 190 kg warhead. The missile was capable of cruising at 4300 kph, reaching altitudes of 30 km, and would have had a range of 300 to 350 km.

Manufacturer: Tupolev. Total Mass: 2,960 kg (6,520 lb). Total Length: 9.60 m (31.40 ft). Span: 2.41 m (7.90 ft). Standard warhead mass: 190 kg (410 lb). Maximum range: 350 km (210 mi). Boost Propulsion: Solid rocket. Cruise Propulsion: Bondaryuk Ramjet. Maximum speed: 4,300 kph (2,600 mph). Ceiling: 30,000 m (98,000 ft).

• Yeftifyev, M D, Iz istorii sozdaniya zenito-raketnovo shchita rossii, Vuzovskaya kniga, Moscow, 2000. Comprehensive history of development of the development of surface-to-air and anti-ballistic missiles in the Soviet Union, with summaries of work in other countries as well. Accessed at: http://www.eastview.com/xq/ASP/sku=A2010232/f_locale=/Evtif'ev/MD/Moskva/Russia/Russian/qx/russian/books/product.asp.