Sukhoi Su-7 (II)

During reorganisation of the Soviet aircraft industry in November 1949, Pavel O Sukhoi's OKB was disbanded, being resurrected three-and-a-half years later, in May 1953, to pursue development of two fighter projects. These were referred to as the S-1 and T-3 respectively, the prefix letters signifying strelovidnyi (arrowhead) and treugolnyi (triangular) in reference to the wing configuration (ie, sweptback and delta). Both aircraft were designed around the large, new Lyulka AL-7 (TRD-31) turbojet, but enjoyed only limited design commonality.

The S-1 was conceived as a so-called "frontal" fighter - a tactical air superiority warplane intended to operate in the vicinity of the battlefront - and was the first Soviet aircraft to feature a slab-type tail and a translating nose cone. Flown on 8 September 1955, the S-1 was initially fitted with an unaugmented AL-7 rated at 6500kg. This was replaced by an afterburning AL-7F of 9500kg with which the S-1 established a national speed record of 2170km/h, or Mach=2.04, in April 1956. Featuring 60° of sweepback, the S-1 had an armament of three 30mm cannon and provision for a retractable ventral tray for 32 spin-stabilised 57mm rockets. Demonstrated over Tushino on 24 June 1956, this prototype crashed on 21 November that year.

A second prototype, the S-2, embodying some aerodynamic refinements, had joined the test programme in the meantime and - although this was not to complete State testing until the autumn of 1957 - manufacture of a pre-series went ahead simultaneously. Built in sufficient quantity to equip a regiment for evaluation purposes, these fighters, which possessed a primary air-to-air role and entered service in the Soviet Far East in early 1959, were assigned the designation Su-7. This repeated the appellation of the mixed-power experimental fighter tested in 1944. A requirement change led to the further development of the basic design as a dedicated ground attack fighter under the designation Su-7B (S-22).