The Czech Republic and Slovakia, once the industrial backbone of the Austro-Hungarian Empire, were the most important military industrial bases of the Austro-Hungarian Empire. After World War II, during the Cold War in the 1970s, the L-39C Albatross high subsonic jet medium/advanced trainer aircraft of Aero Vodochody Airlines in Czechoslovakia became the main medium/high-level trainer aircraft equipped by the Soviet Union and the entire Warsaw Pact air force, as well as the air forces of Iraq, Syria and Libya, due to their low cost, simple structure, high reliability, ease of operation, and ease of repair and maintenance.
L-39C "Albatross" type three-view
By 1993, the L-39 series of medium/advanced trainer aircraft accounted for as much as 80% of the total share of Czech arms exports that year! Today, the L-39C medium/advanced trainer aircraft can still be seen at major air shows and defense exhibitions, but at this time, it is displayed to the world as a special performance aircraft for the "Breitling" aerobatic team. The Breitling Aerobatic Team is also the only folk jet aerobatic team to date.
The Breitling aerobatic team equipped with the L-39C
Development and birth of L-39C type
In 1964, the predecessor of Vodjodi Aviation, the Stredussk Strogelni Aviation Plant (renamed Vodojodi Aviation in 1965), established a C-39 project to replace the old L-29 Dolphin trainer aircraft, which was subsequently formed by Jan. Led by Vörček designers, the C-39 project planning engineering team.
Yang. The designerSer Vörchek proposed a tandem two-seat single-engine jet trainer that could meet the load of weapons under the wings and could also be sold to the Warsaw Pact countries and become the main trainer aircraft for training fighter pilots in the Warsaw Pact Air Force. After several years of research and development and design work, on November 4, 1969, the prototype of the L-39 "Prototype X-02" with fuselage number 3902 successfully made its first flight, which was painted in silver and white with red embellishments throughout, and was piloted by test pilots of Wodojodi Airlines for the first flight.
L-39 "Prototype X-02" prototype
A total of 7 L-39 prototypes were produced to undertake testing tasks such as test flight tests and ground static tests, and in 1971 the L-39 medium/advanced trainer aircraft began production, and the mass production version was named L-39C "Albatross". In 1972, the Warsaw Pact countries officially identified the L-39C as the preferred trainer aircraft of their own air force, and in 1974, the first L-39C medium/advanced trainer aircraft was officially installed in the Czechoslovak Air Force.
Design and technical performance
As an intermediate/advanced trainer aircraft, the L-39C adopts a series of two-seaters + single-engine lower wings, plus a single vertical tail and horizontal tail aerodynamic layout design. The lower wing type belongs to the NACA 64A012 type, with a wing area of 18.8 square meters, the lower wing design makes the L-39C type have excellent flexibility characteristics, the left and right wing tip, but also equipped with a non-removable volume 100 liter wing tip fuel tank.
The L-39C medium/advanced trainer aircraft soaring across the sky
Because the L-39C has the ability to take off and land on the runway of a field airstrip, the rear fuselage is provided with semi-circular air intakes on both sides of the air intake, and the air intakes are separated from the fuselage by a manifold. The higher two-sided intake channels prevent the turbofan engine's front intake fan from causing damage to the turbofan engine blades or even engine scrap when taking off.
In terms of performance, the L-39C type is long; 12.13 m, wingspan; 9.46 meters, body height; 4.77 m, empty weight; 3.45 tons, maximum take-off weight; 4.7 tons, the two hanging points under the left and right wings can carry the total weight; 284 kg load. Normal flight speed; Mach 0.6, maximum flight speed; Mach 0.8, overload; -4 to +8G, maximum range; 1100 km, ceiling; 11 km.
Close-up of the front of the L-39C
In terms of powertrain, an AI-25TL type mid-culvert ratio small thrust turbofan engine developed and designed by the Ivchenko-Progressive Design Bureau was used, and the prototype of the engine was first interviewed in 1966. The engine captain; 3.36 m, diameter; 0.612 m, weight; 0.35 tons, normal thrust; 0.515 tons (5.05 kN), maximum thrust; 1.72 tons (16.9 kN), thrust-to-weight ratio; 4.9;1.
AI-25TL turbofan engine
In terms of structure, the "3-3-9-1-2" design structure of the 3-stage intake fan, the 3-stage low-pressure compressor, the 9-stage high-pressure compressor and the annular combustion chamber and the 1-stage high-pressure turbofan and the 2-stage low-pressure turbine are adopted, and it is worth noting that the medium-pressure and high-pressure compressors are all made of OT4-1 titanium alloy.
Static close-up of the 9-stage high-pressure compressor
L-39C with the "Breitling" performance team
The "Breitling" aerobatic performance team, formerly known as the "Apache" aerobatic performance team established in 1982, although the performance team is of a civilian nature, its members are retired pilots of the French Air Force. In 2003, Breitling, a well-known Swiss watchmaking company, began to exclusively fund the "Apache" aerobatic performance team, and then renamed the "Breitling" aerobatic show team and continues to this day, it is reported that the team can participate in 50 aerobatic performances worldwide every year, and currently has 9 L-39C medium/advanced trainer aircraft as a performance aircraft (No. 0-8).
The members of the Breitling performance team are all retired pilots