Soko J 21 Jastreb

Design and development

The J-21 Jastreb was developed as a replacement for the Republic F-84 Thunderjet, which had been the most commonly used turbojet fighter-bomber aircraft of the Yugoslav Air Force until 1967. On the basis of the G-2 Galeb, the J-21 Jastreb was developed as a single seat ground attack variant, flying for the first time on 19 July 1965.

Pilots sit on licence-built Folland Type 1-B ejection seats under individual canopies hinged on the starboard side in un-pressuried cockpits. Instruments and controls are entirely conventional with manually operated flying controls and standard flight instruments.

Powered by a single BWB licence-built Rolls-Royce Viper Mk531 the Jastreb has a conventional Aluminium Alloy stressed skin structure with few or no special features. The relatively thick aerofoil section, though limiting performance, provides room for fuel cells and the retracted main undercarriage which retracts inwards, giving the Jastreb a wide track and imbuing it with excellent ground handling characteristics. The levered undercarriage legs and relatively low pressure tyres allow the Jastreb to operate from un-prepared strips or rough surfaced airfields.

Compared to the Galeb, the Jastreb has a strengthened structure, allowing more weapons to be carried, including three 12.7 mm (0.5 in) Browning AN/M3 machine guns with 135 rpg, mounted in the nose of the aircraft. As well as the nose-mounted guns, the Jastreb is able to carry up to 800 kg (1,800 lb) on under-wing pylons, two inner pylons having a capacity of 250 kg (550 lb) for bombs, rocket launchers and additional tanks, while the six outer pylons can carry VRZ-157 127 mm (5.00 in) rockets.

Operational history

The J-21 entered service with the JRV (Yugoslavian Air Force) on 31 December 1968, with very few, if any, remaining in service.

First Congo War

According to some reports, France and Yugoslavia supported Mobutu's government during the First Congo War. Namely, Yugoslavia agreed to deliver three J-21 and a single G-2 aircraft, as well as four MiG-21PFMs, while three Mi-24s were purchased from Ukraine. All these aircraft were based at Gbadolite and flown mainly by Serbian mercenaries.

With few exceptions it remains unknown exactly what happened with each of these aircraft and how they were used after their arrival in Zaire, in late 1996-1997. In the case of Mi-24s it is known that one hit a power line and crashed on 27 March 1997, killing the three crewmen and four passengers.

The fate of at least one J-21 Jastreb was not much better: one of the Serbian pilots, Ratko Turčinović, was killed while flying an ultra-low-level pass over Gbadolite, clipping a lamp post with his wing. The wreckage of his aircraft fell directly into a column of young soldiers on a parade, killing dozens. The accident is reported as being attributed to Turčinović's alcohol dependency.

Soon after the accident, the Serbs were expelled from the DRC and the Jastrebs were abandoned along with the Galebs. MiG-21s and Mi-24s, which were awaiting assembly by Russian or Ukrainian technicians at Gbadolite, were also abandoned and can still be seen on the ramp at Gbadolite (2013).

Bosnia and Herzegovina

Six J-21 Jastreb of the Republika Srpska Air Force were engaged by USAF F-16's during Operation Deny Flight. In what would become known as the Banja Luka incident, the Jastreb were engaged after violating the NATO-enforced no-fly-zone. The USAF claimed 4 J-21's as being shot down by F-16's, while the Serbs claimed 5 Jastrebs as lost. The discrepancy likely stems from a damaged Jastreb crashing near the airfield after the F-16's had departed.

Variants

J-21 Jastreb

Single-seat ground-attack, reconnaissance aircraft.

J-21E Jastreb

Export version of the J-1.

RJ-21 Jastreb

Single-seat tactical reconnaissance aircraft.

RJ-21E Jastreb

Export version of the RJ-1.

NJ-21

Two-seat advanced flying trainer / weapons trainer / light ground attack aircraft.

Operators

Libya

Free Libyan Air Force

Former Operators

 Republika Srpska

operated 12 J-21 for training and for ground attack,

Libyan Jamahiriya

Libyan Air Force

 Yugoslavia

Yugoslav Air Force

 Zaire

Zaire Air Force

 Zambia

Zambia Air Force

Serbia

J-21/RJ-21

The original prototype and over 31 J-21s are located at the Museum of Yugoslav Aviation in Belgrade.

Specifications (J-21 Jastreb)

Data from

General characteristics

Crew: 1

Length: 10.88 m (35 ft 8 in)

Wingspan: 10.56 m (34 ft 8 in)

Height: 3.64 m (11 ft 11 in)

Wing area: 19.43 m² (209.1 sq ft)

Max takeoff weight: 5,100 kg (11,244 lb)

Fuel capacity: 440 kg (970 lb) internal fuel + 435 kg (959 lb) in 2x 275 l (60 imp gal; 73 US gal) jettisonable wing-tip fuel tanks.

Powerplant: 1 × BMB (Rolls-Royce/Bristol Siddeley) Viper Mk 531 turbojet engine, 13.32 kN (2,990 lbf) thrust

Powerplant: 2 × JATO units solid-fuelled rockets, 4.45 kN (1,000 lbf) thrust each

Performance

Maximum speed: 820 km/h (510 mph; 443 kn)

Cruise speed: 740 km/h (460 mph; 400 kn) at 5,000 m (16,000 ft)

Range: 1,520 km (944 mi; 821 nmi) with tip tanks

Service ceiling: 12,000 m (39,000 ft)

g limits: +8 -4

Rate of climb: 21 m/s (4,100 ft/min)

Armament

Guns: 3x 12.7 mm (0.5 in) Browning AN/M3 machine guns

Hardpoints: 8 with a capacity of inboard pylons (2 of) 250 kg (550 lb), outboard pylons (6 of) 50 kg (110 lb),with provisions to carry combinations of:

Other:

2x 150 l (33 imp gal; 40 US gal) napalm tank

2x Rocket pods each with 12x 55 mm (2.17 in) rockets

Rockets: 6x VRZ-157 127 mm (5.00 in) rockets

Bombs:

2x 250 kg (550 lb) General Purpose bombs or

2x 150 kg (330 lb) Cluster bombs or

2x 120 kg (260 lb) Cluster fragmentation bombs

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