Staff Writer (Updated: 11/9/2016):
The Su-7 began life as early as 1953 (the final year of the Korean War), to which the Sukhoi OKB firm was reestablished and charged with finding an answer to the North American F-86 Sabre jet fighter. The American jet effectively "stole" the Korean War away from the North Korean/Chinese/Soviet conglomerate, matching wits with the highly-prized Soviet-made Mikoyan-Gurevich MiG-15 "Fagot" single-seat, single engine, swept-wing jet fighter.
A Sukhoi swept-wing design soon emerged as the S-1 "Strela", a prototype revealed by the mid-1950's and fitted with a new Lyulka AL-7 series turbojet engine within a long and slender aerodynamic fuselage. The aircraft featured an open nose assembly for which to feed the engine and air intake was controlled through a variable-position nose cone mounted within the intake itself. First flight was on September 7th, 1955 and further tests allowed the fighter to set an internal Soviet speed record of over Mach 2. Since the S-1 would be called upon in the air-to-air combat role, close-in armament was key to its success and ultimate survival. Sukhoi called on an intended battery of 3 x 37mm Nudelman N-37 series cannons as well as a retractable under-fuselage tray housing up to 32 x 57mm unguided rockets (the Americans fielded similar fighters armed as such, though complimented by machine guns instead of cannon). The S-1 was unveiled to Western eyes in the 1956 Soviet Aviation Day presentation at Tushino Airport near Moscow.
The S-2 prototype soon appeared though this time showcasing a new "slab" tailplane assembly and general external refinements over the S-1. The S-1 was later fatally lost (its test pilot killed) in an accident on November 23rd, 1956. Regardless, the program proceeded and ultimately produced the base Su-7 production-level fighter in 1959.
Like most other early and middle Cold War-era jet fighters, the Su-7 was envisioned in a dedicated ground-attack variant. The S-22 pre-production model was developed for this purpose - based on the S-2 prototype - and brought with it an area-ruled fuselage as well as other refinements. The S-22 was designed in such a way as to take advantage of the aircraft's inherent speed while taking into account the low-level bombing role it would be utilized in. First flight occurred in March of 1959 and, before long, the type emerged as the Su-7B production model in 1961.
In typical NATO fashion, the non-flattering codename of "Fitter" was attached to the Soviet aircraft line. NATO maintained a "healthy" habit of assigning Soviet fighters with "F" based names (MiG-17 "Fresco") while bombers were given "B" names (Tu-85 "Bear").