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Sukhoi S-1 / S-2 / Su-7 (II)

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 with either the 58 degree to 62 degree swept wing, or the 57 degree or 58 degree tailed delta configurations evolved by the Central Aerodynamics and Hydrodynamics Institute. 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 14,330-lb / 6500kg aspirated via a circular nose inlet with a conical inlet centrebody that translated in and out to regulate the supersonic airflow through the inlet. 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 62 degrees 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).

While a small pre-series was being built for service evaluation by the V-VS TacAir component, the Frontovaya Aviatsiya (FA), as the Su-7, a second prototype embodying some aerodynamic refinement, the S-2, joined flight test, and it was this, in productionised S-22 (or S-2-2) form, that was to be ordered into large-scale production in 1958 as the Su-7B.

Su-7 (pre-series)
Max take-off weight: 9423 kg / 20774 lb
Wingspan: 9.15 m / 30 ft 0 in
Length: 16.72 m / 55 ft 10 in
Max. speed: 1827 km/h / 1135 mph

 

 


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