The Sukhoi Su-7 (NATO designation name: Fitter-A) is a swept wing, supersonic fighter aircraft developed by the Soviet Union in 1955. Originally, it was designed as a tactical, low-level dogfighter, but was not successful in this role. On the other hand, the soon introduced Su-7B series became the main Soviet fighter-bomber and ground-attack aircraft of the 1960s. The Su-7 was rugged in its simplicity, but its Lyulka AL-7 engine had such high fuel consumption that it seriously limited the aircraft's payload, as even short-range missions required at least two hardpoints be used to carry drop tanks rather than ordnance.
Design and development[]
After Joseph Stalin's death, the Sukhoi OKB was reopened and by the summer, it began work on a swept-wing front line fighter. The first prototype, designated S-1, was designed to use the new Lyulka AL-7 turbojet engine. It was the first Soviet aircraft to utilize the all-moving tailplane and a translating centerbody, a movable inlet cone in the air intake for managing airflow to the engine at supersonic speeds. The aircraft also had a wing sweep of 60°, irreversible hydraulically boosted controls, and an ejection seat of Sukhoi's own design
The S-1 first flew on 7 September 1955 with A. G. Kochetkov at the controls. Fitted with an afterburning version of the AL-7 engine after the first eleven flights, the prototype set a Soviet speed record of 2,170 km/h (1,170 kn, 1,350 mph, Mach 2. 04) in April 1956. The prototype was intended to be armed with three 37 mm Nudelman N-37 cannons and 32 spin-stabilized 57 mm (2.25 in) unguided rockets in a ventral tray. The second prototype, S-2, introduced some aerodynamic refinements. Testing was complicated by the unreliable engine, and S-1 was lost in a crash on 23 November 1956, killing its pilot I. N. Sokolov. Only 132 have been produced between 1957 and 1960, and the aircraft entered service as Su-7 in 1959.
Su-7A fighter[]
The first production variant: a frontline fighter that saw limited operational use in the Far East from 1958. However, in 1959, a decision was made to prioritize production of the MiG-21, thus less than 200 Su-7As were deployed. The Su-7A was retired in 1965 with operational deployment.
Su-7B fighter-bomber[]
On July 31, 1958, Soviet tactical aviation (Frontovaya Aviatsiya, фронтовая авиация) tasked Sukhoi with developing a ground-attack variant of the Su-7, which could replace the scrapped Ilyushin Il-40. The resulting prototype, designated the S-22, incorporated structural refinements for low-altitude operations at high-speed. The prototype first flew in March 1959; entering service in 1961 as the Su-7B.
Operationally, Su-7s were hampered by a high landing speed of 340–360 km/h. This was dictated by the highly swept wing. Combined with poor visibility from the cockpit and the lack of an instrument landing system, operations were very difficult, especially in poor weather or airfields. In 1961–1962, Sukhoi experimented with blown flaps on S-25 but the benefit was too small to warrant implementation. JATO rockets tested on S-22-4 proved more useful and were incorporated into the Su-7BKL. Attempts to improve takeoff and landing performance eventually resulted in the variable geometry Sukhoi Su-17.
The Su-7B and its variants became the main Soviet ground-attack aircraft of the 1960s. They were also widely exported (691 planes, including some trainers). However, the very short combat radius and need for long runways limited the Su-7's operational usefulness. On the other hand, despite its notoriously heavy controls, the Su-7 was popular with pilots for its docile flight characteristics, simple controls and considerable speed even at low altitudes. It also had a reputation for easy maintenance.
In 1977-1986 the Su-7s remaining in Soviet service were replaced by Su-17s and MiG-27s.