F-7P and F-7PG

TYPE: Fighter and Close Support Aircraft.

PROGRAMME HISTORY

A license to manufacture MiG-21F-13 and its engine (R-11F-300) was granted to China by Soviet Union in early 60s. In the start CKD kits along with some primary documentation were provided by Soviets but then due to changing political relations necessary technical documentation which would have allowed complete manufacture of MiG-21 in China was withheld. Assembly of first J-7 from Chinese-made components was started in early 1964. The static testing of first Shenyang-built J-7 was completed in November 1965 and first test flight took place on 17 January 1966. The Chengdu centre began production of J-7I’s in June 1967, followed by development work on J-7II variant in 1975. The first flight of J-7II was conducted on 30 December 1978 with production approval granted on September 1979. Over the years many improved variants were produced, which are summarized in the table below.

Variant Remarks
J-7 Initial licence version using Chinese-made components built at Shenyang in limited numbers. Followed by J-7I (at Chengdu) version for PLA Air Force, with variable intake shock cone and second 30 mm gun. J-7I was not accepted in large numbers, due mainly to unsatisfactory escape system (front-hinged canopy, to which ejection seat was attached).
F-7A Export version of J-7I, supplied to Albania and Tanzania.
F-7B Export version of J-7II with R550 Magic missile capability, supplied to Eqypt, Iraq and Sudan.
F-7BS Modified version of F-7B supplied to Sri Lanka in 1991.
F-7M F-7M ‘Airguard’ is an upgraded export version developed from J-7II with Western avionics (GEC-Marconi Avionics HUDWAC, new ranging radar, air data computer, radar altimeter, IFF, secure communication radio etc.) The electrical power generation system was also improved to support the new avionics. Additional improvments were, two additional underwing stores points; improved WP7B(BM) engine; birdproof windscreen; strengthened landing gear; ability to carry PL-7 air-to-air missiles; nose probe relocated from beneath intake to top lip of intake, offset to starboard.
F-7P F-7P ‘Airguard’ (briefly called Skybolt) is a variant of F7M, embodying 24 modifications to meet specific requirements of Pakistan Air Force, including ability to carry four air-to-air missiles (Sidewinders) instead of two and fitment of Martin-Baker Mk 10L ejection seat.
F-7MP A further modified variant of F-7P with improved cockpit layout and navigation system incorporating Collins AN/ARN-147 VOR/ILS receiver, AN/ARN-149 ADF and Pro Line II digital DME-42. Avionics (contract for up to 100 sets) delivered to China from early 1989. FIAR Grifo 7 fire-control radar (range of more than 30 n miles; 55 km; 34 miles) for F-7P and MP were orderd ordered by Pakistan Air Force in 1993 to replace GMAv Skyranger.
J-7III Chinese equivalent of MiG-21MF, much redesigned from J-7I with blown flaps and all-weather, day/night capability.
J-7E Upgraded version of J-7II with modified, double-delta wing, retaining existing leading-edge sweep angle of 57° inboard but reduced sweep of only 42° outboard. Wing span has been increased by 1.17 m (3 ft 10 in) and area by 1.88 m{2} (20.2 sq ft), giving 8.17 per cent more wing area. Also has four underwing stations instead of two with outer pair each plumbed for 480 litre (127 US gallon; 106 Imp gallon) drop tank. New WP7F version of WP7 engine, rated at 44.1 kN (9,921 lb st) dry and 63.7 kN (14,330 lb st) with afterburning. Armament generally listed as same as for F-7M, but capability extended to include PL-8 air-to-air missiles. G limits of 8 (up to M0.8) and 6.5 (above M0.8).
F-7MG Improved version of F-7M (G suffix indicates gai: modified), combining double-delta wings of J-7E with upgraded avionics and other changes including uprated (WP13F) engine and leading/trailing-edge manoeuvring flaps. Said to have 45 per cent better manoeuvrability than F-7M. Pakistani version is knows as F-7PG.
FT-7 Tandem two-seat operational trainer based on J-7II and MiG-21US.

Service with Pakistan Air Force

The PAF has two F-7 variants in service. F-7P ‘Skybolt’ which is a variant of the F-7M ‘Airguard’ and F-7PG, which is a variant of F-7MG. There are also two-seater variants, FT-7 and FT-7PG to support the conversion of pilots to F-7P and F-7PG respectively.

The F-7M was evaluated by PAF in early 1987 and for this purpose two aircraft were ferried to Pakistan and trials were conducted at Peshawar and Masroor Air Bases. The evaluation included both air-to-air and air-to-ground performance. After the evaluation, 20 F-7Ps and four FT-7s were ordered and these were delivered to No. 20 Squadron in November 1988.

This was followed by delivery of sixty F-7Ps in 1988-89, fifteen FT-7s in 1990-1992 and forty F-7Ps in 1993. In total 135 aircraft were delivered and these equipped six squadrons and also a squadron of Combat Commanders School. All F-7Ps were ferried to Pakistan by PAF pilots. Later in service, due to operational limitations with existing Sky Ranger 7M GEC Marconi radar, tenders were floated by the PAF in South Africa and Italy for developing a combat mode, small, very economical, but effective radar for PAF’s F-7 aircraft. The Italian FIAT Company was selected out of many of the most reputed radar developing companies, as its offer was very economical and sound. The contact to co-produce 100 Grifo-7 radars by FIAT and KARF at PAC Kamra was signed in June 1993. After the production the facility was converted into depot level maintenance for this radar.

Evaluation of F-7PG (F-7MG) was carried out by PAF pilots in Chengdu in July 1997.  In total 12 sorties were flown to in which complete flight regime was explored, with particular focus on the improvements in performance of the already in-service F-7P. 57 F-7PG (including nine FT-7PG) were ordered in late 2000 to replace the F-6 flown by No. 17 and No. 23 Squadrons. Deliveries began in June 2001.

DESIGN FEATURES

Diminutive tailed delta (double-delta on F-7PG), with clipped tips to mid-mounted wings; circular-section fuselage with dorsal spine; nose intake with conical centrebody; swept tail, with large vertical surfaces and ventral fin. Wing anhedral 2° from roots; incidence 0°; thickness/chord ratio approximately 5 per cent at root, 4.2 per cent at tip; quarter-chord sweepback 49° 6′ 36″ (reduced on F-7PG outer panels); no wing leading-edge camber.

FLYING CONTROLS

Manual operation, with autostabilisation in pitch and roll; hydraulically boosted inset ailerons; plain trailing-edge flaps, actuated hydraulically; forward-hinged door type airbrake each side of underfuselage below wing leading-edge; third, forward-hinged airbrake under fuselage forward of ventral fin; airbrakes actuated hydraulically; hydraulically boosted rudder and all-moving, trimmable tailplane. Leading/trailing-edge manoeuvring flaps on F-7PG.

STRUCTURE

All-metal; wings have two primary spars and auxiliary spar; semi-monocoque fuselage, with spine housing control pushrods, avionics, single-point refuelling cap and fuel tank; blister fairings on fuselage above and below each wing to accommodate retracted mainwheels.

LANDING GEAR

Inward-retracting mainwheels, with 600 x 200 mm tyres (pressure 11.50 bars; 167 lb/sq in) and LS-16 disc brakes; forward-retracting nosewheel, with 500 x 180 mm tyre (pressure 7.00 bars; 102 lb/sq in) and LS-15 double-acting brake. Nosewheel steerable +-47°. Minimum ground turning radius 7.04 m (23 ft 1{1/4} in). Tail braking parachute at base of vertical tail.

POWER PLANT

One LMC (Liyang) WP7B(BM) turbojet (43.2 kN; 9,700 lb st dry, 59.8 kN; 13,448 lb st with afterburning) in F-7M; LMC WP13 turbojet (40.2 kN; 9,039 lb st dry, 64.7 kN; 14,550 lb st with afterburning) in J-7 III/F7-3; WP13F (44.1 kN; 9,921 lb st dry, 64.7 kN; 14,550 lb st with afterburning) in F-7PG.

Total internal fuel capacity 2,385 litres (630 US gallons; 524.5 Imp gallons, contained in six flexible tanks in fuselage and two integral tanks in each wing. Provision for carrying a 500 or 800 litre (132 or 211 US gallon; 110 or 176 Imp gallon) centreline drop tank, and/or a 500 litre drop tank on each outboard underwing pylon. Maximum internal/external fuel capacity 4,185 litres (1,105 US gallons; 920.5 Imp gallons).

ACCOMMODATION

Pilot only, on CAC zero-height/low-speed ejection seat operable between 70 and 459 kt (130 and 850 km/h; 81 and 528 mph) IAS. Martin-Baker Mk 10L seat in F-7P/PP. One-piece canopy, hinged at rear to open upward. J-7 III/F7-3 canopy opens sideways to starboard.

SYSTEMS

Improved electrical system in F-7M, using three static inverters, to cater for additional avionics. Jianghuai YX-3 oxygen system.

AVIONICS

Comms: GMAv AD 3400 UHF/VHF multifunction com, Chinese Type 602 IFF transponder; Type 605A (`Odd Rods’ type) IFF in J-7III.

Radar: FIAR Grifo-7 in F-7P/PG. Chinese JL-7 fire-control radar in J-7III.

Flight: Navigation function of GEC-Marconi HUDWAC includes approach mode. WL-7 radio compass, XS-6A marker beacon receiver, Type 0101 HR A/2 radar altimeter and GMAv air data computer in F-7M. Beijing Aeronautical Instruments Factory KJ-11 twin-channel autopilot and FJ-1 flight data recorder in J-7III. F-7PG suite includes VOR/DME/INS and Tacan.

Instrumentation: GMAv Type 956 HUDWAC (head-up display and weapon aiming computer) in F-7M provides pilot with displays for instrument flying, with air-to-air and air-to-ground weapon aiming symbols integrated with flight-instrument symbology. It can store 32 weapon parameter functions, allowing for both current and future weapon variants. In air-to-air combat its four modes (missiles, conventional gunnery, snapshoot gunnery, dogfight) and standby aiming reticle allow for all eventualities. VCR and infrared cockpit lighting in F-7PG, for which licence-built Russian helmet sight, slaved to PL-9 AAM, is also in production.

Self-defence: Skyranger ECCM in F-7M. Chinese LJ-2 RWR and GT-4 ECM jammer in J-7III.

ARMAMENT (F-7M): Two 30 mm Type 30-1 belt-fed cannon, with 60 rds/gun, in fairings under front fuselage just forward of wingroot leading-edges. Two hardpoints under each wing, of which outer ones are wet for carriage of drop tanks. Centreline pylon used for drop tank only. Each inboard pylon capable of carrying a PL-2, -2A, -5B or -7 missile (and PL-9 on F-7PG) or, at customer’s option, an R550 Magic; one 18-tube pod of Type 57-2 (57 mm) air-to-air and air-to-ground rockets; one Type 90-1 (90 mm) seven-tube pod of air-to-ground rockets; or a 50, 150, 250 or 500 kg bomb. Each outboard pylon can carry one of above rocket pods, a 50 or 150 kg bomb, or a 500 litre drop tank.

 

EXTERNAL DIMENSIONS
Wing Span (except F-7PG) 7.15m (23 ft 5{5/8} in)
J-7E/F-7PG 8.32 m (27 ft 3{1/2} in)
Wing chord at root (except F-7PG) 5.51 m (18 ft 0{3/4} in)
Wing chord at tip (except F-7PG) 0.46 m (1 ft 6{1/4} in)
Wing aspect ratio (except F-7PG) 2.2
Wing aspect ratio of F-7PG 2.8
Length overall (excl nose probe) 13.945 m (45 ft 9 in)
Length overall (incl nose probe) 14.885 m (48 ft 10 in)
Fuselage length 12.175 m (39 ft 11{1/2} in)
Max diameter 1.34 m (4 ft 4{3/4} in)
Height overall 4.105 m (13 ft 5{1/2} in)
Tailplane span 3.74 m (12 ft 3{1/4} in)
Wheel track 2.69 m (8 ft 10 in)
Wheelbase 4.805 m (15 ft 9{1/4} in)
AREAS
Wings, gross (except F-7PG) 23.00 m{2} (247.6 sq ft)
Wings, gross F-7PG 24.88 m{2} (267.8 sq ft)
Ailerons total (except F-7PG) 1.18 m{2} (12.70 sq ft)
Trailing-edge flaps (total) 1.87 m{2} (20.13 sq ft)
Fin 3.48 m{2} (37.46 sq ft)
Rudder 0.97 m{2} (10.44 sq ft)
Tailplane 3.94 m{2} (42.41 sq ft)
WEIGHTS AND LOADINGS
Weight empty: F-7P 5,275 kg (11,629 lb)
Weight empty: F-7PG 5,292 kg (11,667 lb)
Normal T-O weight with 2 PL-2 or PL-7 air-to-air missiles: F-7P 7,531 kg (16,603 lb)
Normal T-O weight with 2 PL-2 or PL-7 air-to-air missiles: F-7PG 7,540 kg (16,623 lb)
Max T-O weight: F-7PG 9,100 kg (20,062 lb)
Wing loading at normal T-O weight: F-7P 327.4 kg/m^2 (67.06 lb/sq ft)
Max wing loading: F-7PG 365.8 kg/m^2 (74.91 lb/sq ft)
Power loading at normal T-O weight: F-7P 126 kg/kN (1.23 lb/lb st)
Power loading at normal T-O weight: F-7PG 141 kg/kN (1.38 lb/lb st)
PERFORMANCE (F-7M at normal T-O weight with two PL-2 or PL-7 air-to-air missiles, except where indicated)
Never-exceed speed above 12,500 m (41,010 ft) M2.35 (1,346 kt; 2,495 km/h; 1,550 mph)
Max level speed between 12,500 and 18,500 m (41,010-60,700 ft) M2.05 (1,175 kt; 2,175 km/h; 1,350 mph)
Touchdown speed 162-173 kt (300-320 km/h; 186-199 mph)
Max rate of climb at S/L 10,800 m (35,435 ft)/min
Acceleration from M0.9 to 1.2 at 5,000 m (16,400 ft) 35 s
Max sustained turn rate: M0.7 at S/L 14.7°/s
Max sustained turn rate: M0.8 at 5,000 m (16,400 ft) 9.5°/s
Service ceiling 18,200 m (59,720 ft)
Absolute ceiling 18,700 m (61,360 ft)
T-O run 700-950 m (2,300-3,120 ft)
Landing run with brake-chute 600-900 m (1,970-2,955 ft)
Range: two PL-7 missiles and three 500 litre drop tanks 939 n miles (1,740 km
Self-ferry with one 800 litre and two 500 litre drop tanks, no missiles 1,203 n miles (2,230 km; 1,385 miles)
G limit +8
PERFORMANCE (F-7PG)
Max operating Mach No. 2.0
Max level speed 648 kt (1,200 km/h; 745 mph)
Min level speed 114 kt (210 km/h; 131 mph)
Max rate of climb at S/L 11,700 m (38,386 ft)/min
Max instantaneous turn rate 25.2°/s
Sustained turn rate: at 1,000 m (3,280 ft) 16°/s
Sustained turn rate: at 5,000 m (16,400 ft) 11°/s
Sustained turn rate: at 8,000 m (26,250 ft) 8°/s
Service ceiling 17,500 m (57,420 ft)
Theoretical ceiling 18,000 m (59,060 ft)
Operational radius: air superiority (hi-hi-hi) with two AIM-9P AAMs and three 500 litre drop tanks, incl 5 min combat with afterburner 459 n miles (850 km; 528 miles)
Operational radius: air-to-ground attack (lo-lo-hi) with two Mk 82 bombs and two 500 litre drop tanks 297 n miles (550 km; 342 miles)
Ferry range 1,187 n miles (2,200 km; 1,367 miles)
G limits +8/-3

 

3-D drawings of F-7PG courtesy of Nextech Soft

http://urbanpk.com/pakdef/pakmilitary/airforce/ac/f7pandpg.html