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Sukhoi Su-7B

su-7b


The S-1, created by the newly-resuscitated design bureau of Sukhoi and to demonstrate M = 2.05 early in its test programme, was the first dedicated interdiction and close air support fighter developed in the Soviet Union since WW2. 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.


With the change in the VVS FA heavy fighter requirement from a primary air-to-air role to that of ground attack, the Sukhoi OKB undertook revision of the basic S-2 "frontal" fighter as the S-22. Embodying some structural changes to cater for the primarily low-level mission, together with equipment and armament changes, the S-22 retained the highly sweptback (60 degrees at quarter chord) wing, circular-section fuselage and Lyulka AL-7F turbojet of the S-2 (Su-7). The first prototype of the ground attack fighter flew in April 1959. Preparations for series production of the S-22 as the Su-7B (the suffix letter signifying Bombardirovshchik) at Novosibirsk had begun prior to the prototype testing, thus allowing this ground attack fighter to enter the VVS FA inventory early in 1960.

 

Suk-Su17-02

 

The Su-7B possessed a gun armament of twin 30mm cannon, and four external stores stations (two fuselage and two wing) had a theoretical maximum ordnance load of four tonnes. The Su-7B was succeeded in 1961 by the Su-7BM (Modifikatsirovanny) with an AL-7F-1 turbojet, this engine, standardised for all subsequent versions, being rated at 7000kg boosted to 10110kg with afterburning.

The Su-7BM (S-22M) also introduced a revised fuel system with prominent external piping ducts along the upper rear fuselage. To improve rough field capability in a version designated Su-7BKL (S-22KL) the flaps were redesigned, provision made for ATO rockets and twin braking chutes, and a unique wheel-skid (kolyosno-lyzhnyi) undercarriage introduced. The main undercarriage members embodied small, extensible steel skids for use on soft ground and were accommodated, when retracted, in bulged bays.

su-7bm
Su-7BM


The definitive series model introduced in the mid 'sixties and remaining in production into the early 'seventies was the Su-7BMK - the suffix letters signifying modifitsirovanny kolyosny - with new mainwheel members (from which the skids had been eliminated) retracting into flush wheel wells. This modification was accompanied by upgrading of the avionics fit, provision of zero-zero ejection seat and standardisation on a further pair of wing stores pylons as introduced by late Su-7BKLs.

Revealed at the 1956 Aviation Day at Tushino were large Sukhoi fighters; one with a swept wing (called Fitter by NATO) and the other a tailed delta (called Fishpot). Both were refined into operational types, losing some of their commonality in the process. The highly swept Su-7B became the standard Soviet bloc attack aircraft, some thousands being supplied to all Warsaw Pact nations and to Egypt, Cuba, India, Syria, Hungary, Iraq and North Vietnam. There are many sub-variants, the -7BM being a STOL roughfield version. Code names of tandem trainers are Su-7U Moujik and Su-9U Maiden.

 

Suk-Su7-01
Su-7B

 

Though criticized for its poor payload/range capabilities, the Sukhoi Su-7 possessed the saving graces of excellent handling qualities, good low-level gust response and manoeuvrability. Remaining in service with 15 air arms in 1984, although almost replaced within Soviet front-line units, it has seen action on several occasion during wars in the Middle East and Indian sub-continent. First flown in 1955, the aircraft entered service four years later in its Su-7B form, under the NATO reporting name 'Fitter-A', and rapidly established itself as the standard fighter-bomber of the Soviet air force and some Warsaw Pact allies. Three progressively improved models followed, but featured insufficient changes to warrant a change of Western designation. In the Su-7BM, underwing stores pylons were doubled to four; the muzzle velocity of the internal cannon was increased; and an uprated engine was fitted, take-off power being further boosted, if required, by two JATO bottles, The aircraft also introduced a radar warning receiver in the tail and two duct fairings running long the spine. Rough-field operation was provided in the Su-7BU, whose large, low-pressure nosewheel tyre is betrayed by a blistered floor to its bay. Further changes of detail were incorporated in the later Su-7BMK, but little could be done to moderate the demands of the thirsty AL-7F engine, which on full afterburner at sea level would consume the entire 2940 litres (647 Imp gal) of internal fuel in a little over eight minutes, Even so, fuel capacity is reduced in the operational trainer versions (Su-7UM and Su7UMK, known to NATO as 'Moujik’) to make way for a second seat, despite a slight lengthening of the fuselage.

Egyptian air force Su-7BMKstrike aircraft have been refitted with a British nav/attack system.

The Sukhoi bureau opted to consider variable geometry for an evolutionary development of the classic Su-7 ground-attack fighter, whose poor payload/range performance could perhaps be transformed by a limited form of variable geometry. It was clear that provision of full variable-geometry wings would require a structural redesign of the fuselage as well as the wings, and was thus impractical. The bureau therefore selected a partial variable-geometry layout in which only the outer wings were pivoted, and this arrangement was used on the S-221 prototype, which was evaluated as the Su-7IG. The modification radically improved the type’s payload/range equation, and the type entered production as a type known variously as the Su-17, Su-20 and Su-22 according to model and engine.

Finally withdrawn from VVS-FA first-line service in 1986, the Su-7B was supplied to Afghanistan, Algeria, Czechoslovakia, Egypt, Hungary, India, Iraq, North Korea, Poland, Romania, Syria, Vietnam and South Yemen.

Su-7B
Type: single-seat close-support and attack
Engine: 1 x Lyulka AL-7F single-shaft afterburning turbojet, 22,046 lb (10.000 kg) thrust
Wing span: 29 ft 3.5  in (8 93 m)
Length (including pitot boom): 57 ft (17.37 m)
Height: 15 ft 5 in (4.70 m)
Range with twin drop tanks: 900 miles (1450 km)
Armament: two 30 mm NR-30 cannon, 70 rounds in wing roots, four wing pylons, inners rated at 1,653 lb (750 kg) and outers at 1,102 lb (500 kg), but when two tanks are carried on fuselage pylons total external weapon load is reduced to 2.205 lb (1000 kg)

Su-7BKL

Su-7BM
Type: single-seat close-support and attack
Engine: 1 x Lyulka AL-7F single-shaft afterburning turbojet, 22,046 lb (10.000 kg) thrust
Wing span: 29 ft 3.5  in (8 93 m)
Length (including pitot boom): 57 ft (17.37 m)
Height: 15 ft 5 in (4.70 m)
Empty wt: 19,000 lb (8620 kg)
Max loaded wt: 29,750 lb (13,500 kg)
Max speed at alt. clean: 1055 mph (1700 km/h, Mach 1.6)
Initial climb: 29,900 ft (9120 m)/min
Service ceiling: 49,700 ft (15.150 m)
Range with twin drop tanks: 900 miles (1450 km)
Armament: two 30 mm NR-30 cannon, 70 rounds in wing roots, four wing pylons, inners rated at 1,653 lb (750 kg) and outers at 1,102 lb (500 kg), but when two tanks are carried on fuselage pylons total external weapon load is reduced to 2.205 lb (1000 kg).

Su-7BMK 'Fitter-A'

Type: single-seat ground-attack fighter
Armament: two 30-mm NR-30 cannon (with 70 rpg) in wing roots; six weapon pylons: two under fuselage and two under the inner wings, each carrying up to 500 kg (1,102 lb) of stores, plus two under the outer wings each carrying up to 250 kg (551 lb); weapon load reduced to 1000 kg (2,205 lb) when two 600-litre (132-Imp gal) droptanks are carried on fuselage pylons
Powerplant: one 10000-kg (22,046-1b) thrust Lyulka AL-7F7-1 afterburning turbojet
Maximum speed at sea level 850 km/h (528 mph) without afterburning, or 1350 kph (839 mph) with afterburning
Initial climb rate 9120 m (29,920 ft) per minute
Service ceiling 15150 m (49,705 ft)
Empty weight: 8620 kg (19,004 lb)
Normal take-off weight: 12000 kg (26,455 lb)
Maximum take-off 13500 kg (29,762 lb)
Wingspan 8,93 m (29 ft 3.5 in)
Length, including probe 17,37 m (57 ft 0 in)
Height 4.57 m (15 ft 0 in)
Wing area 27.60 sq.m (297 sq ft)

Su-7IG

Su-7U
Type: dual control trainer
Engine: 1 x Lyulka AL-7F single-shaft afterburning turbojet, 22,046 lb (10.000 kg) thrust
Wing span: 29 ft 3.5  in (8 93 m)
Length (including pitot boom): 57 ft (17.37 m)
Height: 15 ft 5 in (4.70 m)
Range with twin drop tanks: 900 miles (1450 km)
Armament: two 30 mm NR-30 cannon, each with 70 rounds in wing roots, four wing pylons, inners rated at 1,653 lb (750 kg) and outers at 1,102 lb (500 kg), but when two tanks are carried on fuselage pylons total external weapon load is reduced to 2.205 lb (1000 kg)

Su-7UM


Su-7UMK

su-7b-ld
Sukhoi Su-7B

 

 

 


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