Sukhoi Su-7 BKL
NATO reporting names: Fitter-A and Moujik
Type Single-seat ground attack fighter.
Programme
The first prototype of this single-seat fighter, designated S-1, was flown for the first time by test pilot A G Kochetkov on 8 September 1955, and was displayed in prototype form in the flypast over Moscow in the 1956 Soviet Aviation Day. It was the first Soviet aircraft to have all-moving horizontal tail surfaces and a fore and aft translating air intake centrebody to adjust supersonic air flow. Power plant was, successively, an AL-7 turbojet and AL-7F; armament comprised three NR-30 guns. The S-1 prototypes were followed by a number of S-2s, embodying certain aerodynamic refinements and by a small number of preseries aircraft designated Su-7. After evaluation of these, a new prototype, known as the S-22, was built in fighter-bomber form. It was flown for the first time in April 1959, by Ye S Soloviev; and the S-22 was ordered into series production as the Su-7B Fitter-A fighter-bomber, air combat and reconnaissance aircraft.
Versions
Su-7BM: All now withdrawn. Su-7BKL (S-22KL = koleso-lyzhny, wheel-ski): Version with an ALF1-1-200 turbojet, a low-pressure nosewheel, small extensible skid outboard of each mainwheel.
Su-7BMK: Export version of Su-7BKL.
Su-7UM/UMK (U-22): Two-seat operational trainer version. NATO reporting name Moujik. One example remains in service in Russia as an ejection seat trials platform at the Zhokovsky Flight Test Institute. Operators The Su-7BMK is in service with the armed forces of North Korea (30) and Turkmenistan (3 with doubtful serviceability).
The following description applies to the Su-7BMK: Design Features Cantilever mid-wing monoplane. Wing thickness/chord ratio 8 per cent. No dihedral or anhedral. Sweepback 60º on leading-edges. Wing chord is extended giving a straight trailing-edge on inboard section of each wing. Two boundary layer fences on each wing at approximately mid-span and immediately inboard of tip. Two intake suction relief doors on each side of nose. Two slim duct fairings along top of centre-fuselage.
Flying Controls
Hydraulically powered spring-loaded ailerons. Large chord flaps over entire trailing-edge from root to inboard end of aileron on each wing. No slats or tabs. Two hydraulically actuated door-type airbrakes at top and bottom on each side of rear fuselage. The tail unit has hydraulically powered control surfaces, all-moving horizontal surfaces, with anti-flutter bodies projecting forward from tips. Conventional rudder with yaw damper. No tabs.
Structure
Conventional all-metal two-spar structure. The fuselage is a conventional all-metal semi-monocoque structure of circular section. Break point at wing trailing-edge permits removal of rear fuselage for engine servicing. The tail unit is a cantilever all-metal structure with 55º sweepback at quarter-chord on all surfaces.
Landing Gear
Retractable tricycle type, with single wheel on each unit. Steerable nosewheel retracts forward, main units inward into wings. Differential brakes on mainwheels. Twin brake-chutes in large container with clamshell doors, at base of rudder.
Power Plant One Lyulka AL-7F-1-100 (TRD-31) turbojet engine, rated at 66.64 kN (14,980 lb st) dry and 94.08 kN (21,150 lb st) with afterburning. Time taken for afterburner light up 6 to 7 seconds. Variable area afterburner nozzle.
Saddle fuel tanks in centre-fuselage and integral tanks between spars of inner wings.
Total internal fuel capacity 2,940 litres (776 US gallons; 647 Imp gallons). Gravity fuelling points above fuselage tanks and each wing tank. Provision for two drop tanks side by side under fuselage, with total capacity of 1,200 litres (317 US gallons; 264 Imp gallons); and two ferry tanks, total capacity 1,800 litres (475 US gallons; 396 Imp gallons) on inner wing pylons. Two SPRD-100 solid-propellant rocket units, each 29.4 kN (6,610 lb st), can be attached under rear fuselage to shorten T-O run.
Accommodation
Pilot only in pressurised cockpit, on KS-4 zero-altitude rocket-powered ejection seat, under rearward sliding blister canopy. Flat windscreen of armoured glass. Rearview mirror on top of canopy.
Systems
Main and standby hydraulic systems, with emergency pump, for actuating flying controls, flaps, airbrakes, landing gear, nosewheel steering and afterburner nozzle. Cockpit heating system. KKO-2 oxygen system. Pneumatic system adequate for engine starting and three afterburner engagements per sortie, with reserves. Electrical system includes navigation lights and retractable taxying light under nose.
Avionics and Equipment
Standard avionics include VHF/UHF radio, ILS, RSIU very short-wave fighter radio, ADF, transponder, SRO-2M (NATO `Odd Rods’) IFF, Sirena 3 tail warning radar, ranging radar in air intake centrebody, autopilot. Launcher for Very cartridges or chaff under starboard wingroot leading-edge. Provision for vertical and oblique cameras in belly aft of nosewheel bay.
Armament Two 30 mm NR-30 guns, each with 70 rounds, in wingroot leading-edges. ASP-5ND gyro gunsight. Six external stores pylons. Two underbelly pylons and inner underwing pylons each capable of carrying 750 kg (1,650 lb); outer underwing pylons each stressed for 500 kg (1,100 lb). Stores include UB-16-57U rocket pods (each 16 57 mm S-5, S-5M or S-5K rockets), S-24 250 kg concrete-piercing guided rockets, S-3K unguided rockets, and free-fall bombs (usually two 750 kg and two 500 kg), including nuclear weapons. When underbelly fuel tanks are fitted, maximum external weapons load is 1,000 kg (2,205 lb).
Dimensions, External
Wing span 8.77 m (28 ft 9¼ in)
Length overall, incl probe 16.80 m (55 ft 1½ in)
Height overall 4.80 m (15 ft 9 in)
Areas
Wings, gross 23.0 m2 (247 sq ft)
Weights and Loadings
Operating weight empty 8,328 kg (18,360 lb)
Normal T-O weight 12,000 kg (26,450 lb)
Max T-O weight 13,440 kg (29,630 lb)
Performance
Max level speed at 12,200 m (40,000 ft):
`clean’ M1.6 (917 kt; 1,700 km/h; 1,055 mph)
with external stores M1.2 (685 kt; 1,270 km/h; 788 mph)
Max level speed at S/L:
without afterburning 460 kt (850 km/h; 530 mph)
with afterburning 625 kt (1,158 km/h; 720 mph)
Rotation speed for T-O 195 kt (360 km/h; 224 mph)
Approach speed 195 kt (360 km/h; 224 mph)
Max rate of climb at S/L 9,000 m (29,525 ft)/min
Service ceiling 18,000 m (59,050 ft)
T-O run 2,400 m (7,875 ft)Combat radius 135-187 n miles (250-345 km; 155-215 miles)
Max range 780 n miles (1,450 km; 900 miles)
Fuel consumption with afterburning at S/L 360 kg (794 lb)/min
Sukhoi Su-7BKL `Fitter-A’Sukhoi Su-7B `Fitter-A’ fighter-bomber. No longer in service (Sukhoi)
Height (m): 4.80
Length (m): 16.80
Max Level Speed (kts): 460
Max Range (nm): 780
Max Rate Climb (m/min): 9000
Max T-O Weight (kg): 13440
Service Ceiling (m): 18000
T-O Run (m): 2400
Wing Span (m): 8.77
