Su-7 FITTER A (SUKHOI)
The Sukhoi Su-7 is a single seat ground attack aircraft that was long a standard tactical fighter-bomber with the Soviet Air Force. The development of Su-7 began in the early 1950's. First prototype called S-1 "Strela" made its first flight in 1955. The Su-7 was unveiled to the West at the 1956 Soviet Aviation Day display at Tushino Airport outside Moscow. The prototype came out to be very promising and Su-7 went in production several years later, with modifications including the Su-7B and Su-7BKL. The airplane was exported to Czechoslovakia, Poland, Romania, China, and other countries.
The Su-7 is armed with two 30mm NR-30 guns in wing roots, each with 70 rounds. Under-wing pylons allow two 742 kg or two 495 kg of bombs or rocket pods. The wings are mid- to low-mounted (wings are mounted below center of aircraft) with wide wing roots, swept-back, and tapered with blunt tips. There is one engine in the body. There is a circular air intake in the nose and a large, single exhaust. The fuselage is a long, tubular body with a blunt nose and rear. There is a large, bubble canopy. The tail is swept-back and has a tapered tail fin with a blunt tip. It has swept-back and tapered flats mid- to low-mounted on the fuselage.
On 14th May 1953, by order of MDI No 223, P.O. Sukhoi was appointed to replace V.V. Kondratyev as Chief Designer of the OKB-1 design bureau, which had been set up a year before to copy the US F-86 "Sabre" fighter. By MAI Order No 135 of 26th October 1953, the OKB-1 design bureau was assigned a branch of plant No 155 (MAI's former plant No 51) to be used as its production facility.
In November 1949, a government's resolution scrapped the Design Bureau, not to be resurrected till May 1953, when it was set up with new production facilities. The Design Bureau got a new lease on life with the advent of supersonic jet aviation. That is why the design team's major projects at the initial stage were the supersonic fighters S-1 and T-3. As of summer 1953, the Design Bureau was engaged in designing supersonic fighters in two configurations: swept and delta wing (letter designations "S" and "T" respectively, the letter "T" indicating the wings were treugolonyi, or delta shaped). Officially, the go-ahead for the work was given by a decree of the government of 5th August 1953. The S-1 provided a platform for the family of fighter-bombers, the Su-7 and Su-17, and more than 20 versions of them, with the Su-17 becoming the USSR's first aeroplane with a variable sweep wing.
The conceptual design for a swept-wing front-line fighter (version S-1) passed preliminary design review in November 1953, and a mock-up committee review in February 1954. Six months later, in August 1954, a swept-wing fighter/interceptor (S-3) design also passed review, but work on that version was discontinued shortly thereafter.
The design of the S-1 aeroplane and systems incorporated a variety of innovations: a wing with 60º sweep in the ¼ bisecant line, all-movable CS, adjustable axial nose air intake, new high-performance AL-7F turbojet (developed by OKB-165 design bureau) with projected afterburning thrust of 10,000 kg, hydraulic system with operating pressure of 210 kg/cm², a power control system, dual-chamber boosters, a proprietary-design ejection seat, and other features.
The prototype was built in June 1955, and delivered to FRI on the night of 15th July. The S-1 flight-test team was headed by leading engineer V.P. Baluyev. A.G. Kochetkov from GNIKI was appointed the leading test pilot under an agreement with the Air Forces as the Design Bureau had no in-house pilots as yet. On 27th July the aircraft performed its first taxiing, with its maiden flight taking place on 7th September 1955. The first stage of the manufacturer's testing was performed using the AL-7 engine (i.e., AL-7F without afterburning) and was completed in January 1956, a total of 11 flights having been performed. Beginning March 1956, GNIKI test pilot V.N. Makhalin continued S-1 testing with the operational AL-7F.
By that time, the OKB-155 Design Bureau (Designer General A.I. Mikoyan) had started testing of the first prototypes of the future MiG-21. The MAI leadership, in an attempt to showcase the high capabilities of new aircraft of domestic origin, tacitly encouraged competition between the two design bureaus. The first to "make it" was the Design Bureau of P.O. Sukhoi: on 9th June, a S-1 test flight recorded a flight speed of 2,070kph, which was 270kph higher than the performance requirement (PR)! As a result, a decree of the government of 11th June 1956, ahead of governmental testing, put the aircraft into small-batch production at plant No 126 in Komsomolsk-on-Amur under the designation Su-7. On 24th June 1956, together with other new aircraft from the Soviet aviation, the S-1 was publicly unveiled during the traditional air display at Tushino. The building of a second prototype, S-2, had been completed by the autumn of 1956, with its flight testing starting in October.
Official testing of the Su-7 started in September 1956 and continued, on and off, till December 1958. The main problems were due to the extremely unreliable performance of AL-7F engine. This was specifically the cause of the writeoff of the first prototype on 23rd November 1957 and resulting death of Air Forces GNIKI test pilot I.N. Sokolov. As a result, the AL-7F Su-7 variant had a limited production run, it having been recommended to outfit the aircraft with an upgraded engine version, the AL-7F-1. The Su-7 front-line fighter was manufactured from 1957 to 1960, with a total of 132 aeroplanes produced (production runs 1 to 12). The first series Su-7s were put into operational service in the summer of 1959 with the fighter regiment stationed at the Vozdvizhenka aerodrome. In 1959-60, the regiment was used for service testing of the aeroplane. The Su-7 fighters were in service with USSR Air Forces and ADF in the Far East till 1965.
A Su-7B-based two-seat combat trainer aeroplane was developed by the Design Bureau in 1962, but with the Design Bureau using its branch based at the Komsomolsk-on-Amur production plant to build it, it took a long time to complete: the first prototype aeroplane, U22-1, was not flight-tested until 25 October 1965, with the design bureau's test pilot Ye.K. Kukushev at the controls. The manufacturer's tests of the aeroplane were carried out under a tight schedule, in just two months, with the official tests completed in May 1966. The Su-7U two-seat trainer was produced from 1966 to 1972, with an export version, the Su-7UMK, manufactured over the same period. Interestingly, Su-7Us were delivered not only to Air Force regiments armed with the Su-7, but also to ADF units with Su-9 and Su-15 interceptors in the inventory, as the latter units were often suffering from a shortage of two-seaters such as the Su-9U and Su-15UT.
A total of 1,847 Su-7-type planes of all versions and variants were made over the entire production period, with 691 planes exported to 9 countries. The Su-7B type aircraft was kept in the inventory of the USSR Air Forces till the mid-'80s, with up to 25 combat units of fighter-bomber aviation (FBA) equipped with such aircraft during the period of peak deployment in the late '60s - early '70s. Beginning in 1977, the Su-7Bs were gradually replaced in FBA regiments with Su-17 and MiG-27 type aeroplanes.
The Design Bureau and FRI used the Su-7B to try out several flying laboratories, viz.: 100LDU developed on the Su-7U platform to test the system for remote control of the T-4 ("100") missile carrier and the Su-27 fighter, and FL for testing new Su-7U-based rescue aids.
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