L-39 Albatros Trainer or Ground Attack Aircraft, Czech Republic

The L-39 Albatros is a two seat, single engine aircraft designed and manufactured by Aero Vodochody for the Czechoslovakian Air Force. It was the first airplane to be powered by turbofan engines and was later upgraded to the L-59 Super Albatros.

The aircraft is built based on its predecessor L-29 Maya / Delfin aircraft. About 2,900 L-39 are currently in service with 30 air forces worldwide.

Algeria awarded a contract to Aero Vodochody in June 2010 to supply L-39 aircraft. Another contract was signed with Yemen in February 1999 to deliver 12 L-39C jet trainers.

Variants

The L-39 has 12 variants including L-39X-01 – X-07, L-39C, L-39CM, L-39M1, L-39V, L-39ZO, L-39ZA, L-39ZAM, L-39ZA/ART, L-39MS, L-139 Albatros 2000 and L-159.

L-39C is an advanced version fitted with two pylons under each wing and can be used for standard training missions.

L-39CM is principally used for advance training.

L-39M1 is a modern version of L-39C and is fitted with AI-25TLSh engines.

L-39V is a single seat version developed for Czechoslovakia's pilot training missions.

L-39ZO is a weapon trainer aircraft fitted with four pylons which can accommodate 1,150kg of payload. This variant completed its maiden flight in June 1975 and entered service with Iraq in 1977.

L-39ZA is an armed variant based on the L-39ZO. It is fitted with a 23mm Gsh-23L twin barrelled cannon and K-13 or R-60 air-to-air missiles.

L-39ZA/ART is fitted with an Elbit's avionics system.

L-39MS is an extended version of the L-39 jet trainer. It is fitted with a reinforced fuselage, a longer nose, a tandem seat cockpit and a Lotarev DV-2 engine.

L-139 Albatros 2000 is a modified version incorporated with western avionics and Garrett TFE731-4-1T engine.

L-159 is a modern trainer conciliated with foreign avionics and Honeywell F124 engine.

Design

Jan Vicek undertook the design work for the L-39 in 1966. The aircraft is designed to execute basic and advanced pilot training, operational training, border patrol, target simulation and light combat attack missions.

It is designed to incorporate five main rubber bag fuel tanks behind the cockpit. Each fuel tank can accommodate 1,055l of fuel.

Two more fuel tanks having capacity of 100l each have been installed on the non-jettisonable wingtips. The jet trainer is additionally fitted with two 350l drop tanks on the in-board underwing pylons thereby increasing the overall fuel capacity to 1,955l.

Development

The development of the L-39 Albatros began in the 1960s. The maiden flight of the aircraft was completed in November 1968.

Full production was delayed until 1972 due to bugs in the air intake design. The L-39 entered service with the Czechoslovakian Air Force in 1974 when the design faults had been overcome.

Features

The long pointed nose fitted at the front cockpit of the L-39 features electronic equipment and an on-board oxygen generating system. The aircraft is fitted with a smoke generation system, an escape system, tri-cycle type landing gear, anti-collision lights and landing lights.

It is also fitted with a SAFIR 5 Auxiliary Power Unit which has an automatic engine start capability during ground and emergency engine restarts.

Cockpit

The L-39 features a pressurised cockpit fitted with two Czech VS-1-BRI rocket-aided ejection seats in which the rear seat is slightly elevated.

The cockpit is equipped with a mission computer, head-up display (HUD), multi-functional display (MFD), air data computer (ADC) and up-front control panel.

An instrument landing system, an information friend or foe transponder, an electronic standby instrument system, a tactical air navigation system, and Bendix / King distance measuring equipment form part of the cockpit.

The communication and navigation devices installed in the aircraft encompass hands on throttle and stick control system, very high frequency radio, global positioning system and inertial navigation system.

Avionics

The avionics suite equipped in the L-29 includes a horizontal situation indicator, a radio altimeter, an intercom and radio control panel, a radio magnetic indicator, a standby radio control panel, an electronic flight instrument system and an attitude heading and reference system.

Armaments

The L-39 has four hardpoints of which two are located on each wing and two under the wingtips. It can accommodate 1,000kg of payload. The aircraft is equipped with a 23mm Gsh-23 two barrelled cannon which can fire munitions at a rate of 150 rounds per minute.

FFAR or CRV-7 rockets and AIM-9 air-to-air missiles are also housed in the aircraft. All armaments can be managed through weapon control panel installed in the front cockpit.

Engine

The L-39 Albatros is powered by a single Ivchenko AI-25 TL twin-shaft turbofan engine which can produce a maximum thrust of 16.87kN.

The length and width of the engine are 3.3m and 0.98m respectively. The height is 0.95m. Each engine weighs around 350kg and its assigned service life is 4,000 hours.

Performance

The L-39 can climb at the rate of 21m/s. The maximum and cruise speed of the aircraft are 910km/h and 750km/h respectively. Its stall speed is 158km/h. The maximum range is 1,350km.

The service ceiling is 11,000m. Its maximum endurance is two hours and 45 minutes. The aircraft weighs around 3,400kg and its maximum take-off weight is 4,700kg.