AERO L-39 and L-139 ALBATROS

TYPE: Basic jet trainer/light attack jet.

PROGRAMME: First flight 4 November 1968; 10 preproduction aircraft from 1971; selected 1972 to succeed L-29 as standard trainer for USSR, Czechoslovakia and East Germany and production started same year; service trials in USSR and Czechoslovakia 1973; entered service with Czechoslovak Air Force 1974. Worldwide fleet has accumulated more than 4 million flying hours. Modular upgrades being offered for all L-39 variants.

CURRENT VERSIONS: L-39 C: Initial pilot trainer, with two underwing stations. Different parameters from current versions. Most recent export customer (Yemen) ordered 12 in February 1999; delivered September to December same year. Eight Czech Air Force aircraft recently refurbished with new wings, front and rear fuselages and other changes under contracts placed in June and November 1999, for one and seven respectively; first aircraft (0113) redelivered 15 December 1999, remainder by May 2000.
L-39 V: Target towing version for Czech and former East German use; eight only.
L-39 ZO (Z = Zbrojni: armed): Reinforced wings with four underwing stations; first flight (X-09) 25 August 1975. Production completed. Different parameters from current versions.
L-39 ZA: Ground attack and reconnaissance version of Z0; four underwing stations and centreline gun pod; reinforced wings and landing gear; prototypes (X-10 and X-11) flown 29 September 1976 and 16 May 1977; production continuing in 2000 for possible future orders. Customer versions completed with Western equipment (HUD, mission computer, Bendix/King avionics and navigation equipment) as L-39 ZA/MP (for multipurpose). Version for Thailand has Elbit avionics and is designated ZA/ART; deliveries to RTAF began in 1993. Repeat orders placed by Algeria and Nigeria in 2001.
Following shortened description applies to ZA version except where indicated.
L-39 MS: Developed version, similar to L-59. Different parameters from current versions.
L-59: Advanced training version with more powerful engine and improved avionics; no longer in production. Different parameters from current versions.
L-139 Albatros 2000: Trainer, powered by 18.15 kN (4,080 lb st) TFE731-4-1T turbofan under preliminary Aero/AlliedSignal agreement signed June 1991; Flight Visions HUD and Bendix/King avionics; VS-2A zero/zero seats. First flight (5501) 8 May 1993. Demonstrated to air forces of Colombia and Venezuela in 2000. No orders by February 2003; possible upgrade with some L159 avionics still being considered at that time.

CUSTOMERS: Total of 2,935 L-39/59s built (excluding five prototypes) by December 1999; none further by 2002; see table. Eight L-39ZAs (origin unknown) refurbished by Israel Aircraft Industries for Cambodian Air Force; deliveries by IAI began in late 1996/early 1997. Late 2001 orders by Algeria (17), which probably to be taken from 27 undelivered from 1992 Nigerian order.

DESIGN FEATURES: Tandem two-seater with ejection seats and pressurisation; fixed tip tanks also contain navigation/ landing lights; rear fuselage and tail, attached by five bolts, allow easy removal for access to engine; tapered wing has NACA 64A012 Mod.5 section; quarter-chord sweepback 1° 45'; dihedral 2° 30' from roots; incidence 2°.

FLYING CONTROLS: Conventional and manual, by pushrods. Electrically actuated trim tab in each elevator; balance tab in rudder; mass-balanced ailerons with balance tabs (port tab actuated electrically for trimming); two airbrake panels under fuselage just below wing leading-edge, operated by single hydraulic jack, extend automatically as speed approaches M0.8; double-slotted flaps extended by rods from single hydraulic jack, retracting automatically as airspeed reaches 167 kt (310 km/h: 193 mph).

LANDING GEAR: Retractable tricycle type, with single wheel and oleo-pneumatic shock-absorber on each unit; designed for touchdown sink rate of 3.4 m (11.15 ft)/s at AUW of 4,600 kg (10,141 lb). Retraction and extension operated hydraulically, with electrical control. All wheel well doors close automatically after wheels are lowered, to prevent ingress of dirt and debris. Mainwheels retract inward into wings (with automatic braking during retraction), nosewheel forward into fuselage. K28 mainwheels with 610x215 tyres and K27 nosewheel with 450x165 tyre. Hydraulic disc brakes and anti-skid units on mainwheels; shimmy damper on nosewheel leg. Minimum ground turning radius (about nosewheel) 2.50 m (8 ft 2 in). L-39 ZA can operate from grass strips with bearing strength of 6 kg/cm2 (85 lb/sq in).

POWER PLANT: One 16.87 kN (3,792 lb st) ZMKB Progress AI-25 TL turbofan in rear fuselage, with semi-circular lateral air intake, with splitter plate, on each side of fuselage above wing centre-section.
Fuel in five rubber main bag tanks aft of cockpits, with combined capacity of 1,055 litres (279 US gallons; 232 Imp gallons), and two 100 litre (26.5 US gallon; 22.0 Imp gallon) non-jettisonable wingtip tanks. Total internal fuel capacity 1,255 litres (332 US gallons; 276 Imp gallons). Gravity refuelling points on top of fuselage and on each tip tank. Provision for two 150 or 350 litre (39.6 or 92.5 US gallon; 33.0 or 77.0 Imp gallon) drop tanks on inboard underwing pylons, increasing total overall fuel capacity to a maximum of 1,955 litres (517 US gallons; 430 Imp gallons). Fuel system permits up to 20 seconds of inverted flight.

ACCOMMODATION: Crew of two in tandem, on Czech VS-1-BRI rocket-assisted ejection seats, operable at zero height and at speeds down to 81 kt (150 km/h; 94 mph); individual canopies hinge sideways to starboard and are jettisonable. Rear seat elevated. One-piece windscreen hinges forward for access to front instrument panel. Internal transparency between cockpits. Dual controls standard.

AVIONICS (L-39 ZA/ART): Comms: ARC-186 VHF (30 to 78 MHz/FM and 108 to 151.75 MHz/AM) and ARC-164 VHF (220 to 399.975 MHz) radios; Bendix/King KXP756 transponder; IFF. Orbit crew intercom.
Flight: Bendix/King KNR 634A VOR/glideslope/MKR; KTU 709 Tacan; RV-5M radar altimeter.
Instrumentation: Elbit WDNS (weapon delivery and navigation system) with HUD and video camera in front cockpit and monitor in rear cockpit.

ARMAMENT (L-39 ZA/ART): Underfuselage pod below front cockpit, housing a single 23 mm GSh-23 two-barrel gun; ammunition (maximum 150 rounds) housed in fuselage above gun pod. Gun/rocket/missile firing and weapon release controls in front cockpit only. Four underwing hardpoints, inboard pair each stressed for up to 500 kg (1,102 lb) and outer pair for up to 250 kg (551 lb) each; maximum underwing stores load 1,000 kg (2,205 lb). Non-jettisonable pylons, each comprising an MD3-57D stores rack. Typical underwing stores can include various combinations of bombs (two of up to 500 kg or four of up to 250 kg); four rocket launchers for 2.75 in FFAR or CRV7 rockets; AIM-9 air-to-air missiles (outboard stations only); two 150 or 350 litre drop tanks (inboard stations only); or two training dispensers.


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