title: Ivchenko AI-25
text: # Ivchenko AI-25
  
  The Ivchenko AI-25 is a family of military and civilian twin-shaft medium bypass turbofan engines developed by Ivchenko OKB of the Soviet Union. It was the first bypass engine ever used on short haul aircraft in the USSR. The engine is still produced by Ukrainian based aircraft engine manufacturing company, Motor Sich.
  
  ## Development
  
  The AI-25 was designed to power the Yakovlev Yak-40 tri-jet airliner, often called the first regional jet transport aircraft, and is the starting point for the Lotarev DV-2 turbofan engine. The project was launched in 1965, with the AI-25s first test flight in 1966, and finally cleared for production in 1967. In 1972, the AI-25 was selected for the Polish PZL M-15 Belphegor, the world's only jet-powered biplane.
  
  Development of the AI-25 continued and the uprated AI-25TL was designed for use by the Czechoslovak Aero L-39 Albatros military trainer with the first flight occurring in 1968. The L-39, would go on to become one of the most popular, and widespread trainer aircraft in the world, with over 3,000 L-39s produced, and with 2,900 examples still in active service today. A smaller version of the AI-25TL, the AI-25TLK has equipped the People's Republic of Chinas Hongdu L-11 fighter-trainer.
  
  The AI-25TLK is also licensed built in the People's Republic of China as the WS-11. Another variant of the AI-25, is the AI-25TLSh in the 1990s, which underwent flight testing by the Ukrainian Ministry of Defense in 2002. Ivchenko-Progress is currently marketing the AI-25TLSh as an upgrade to existing L-39 and JL-8 operators that would extend the service life of the aircraft and improve performance. The latest AI-25 is the AI-25TL Series 2 designed for the Mikoyan MiG-AT.
  
  For the demand of a stronger turbofan engine by Turkey for its jet-powered Bayraktar MIUS UAV the Ukrainian company developed the stronger AI-25TLT variant
  
  ## Variants
  
  ### AI-25TLT
  
      (Black Sea Shield - turbofan) The AI-25TLT licence-built by Turkish-Ukrainian joint venture BSS based in Istanbul for the Bayraktar MIUS
  
  ### WS-11
  
      (WoShan - turbofan) The AI-25TLK licence-built in China for the Hongdu L-11
  
  ### Walter Titan
  
      (AI-25WM)
  
  ## Applications
  
  * Aero L-39 Albatros
  * Comp Air Jet
  * Hongdu JL-8
  * PZL M-15 Belphegor
  * Yakovlev Yak-40
  * KB SAT SR-10
  * Bayraktar MIUS
  
  ## Specifications (AI-25TL)
  
  Data from
  
  **General characteristics**
  
  * Type: Medium Bypass Turbofan
  * Length: 3,358 mm (132.2 in)
  * Diameter: ~611.6 mm (24.08 in)(intake casing)
  * Dry weight: 350 kg (770 lb)
  
  **Components**
  
  * Compressor: Axial, 3 fan/low pressure compressor stages, 9 high pressure compressor stages
  * Combustors: Annular
  * Turbine: 1 high pressure turbine stage, 2 low pressure turbine stages
  * Fuel type: Aviation kerosene, JP-1 for example
  * Oil system: Pressure spray with return
  
  **Performance**
  
  * Maximum thrust: Takeoff: 1,720 kgf (16.9 kN; 3,800 lbf); Cruise: 515 kgf (5.05 kN; 1,140 lbf)
  * Overall pressure ratio: 9.5:1
  * Bypass ratio: 2.0:1
  * Fuel consumption: 468.1 kg/h (1,032 lb/h)
  * Specific fuel consumption: Takeoff: 17 g/(kN⋅s) (0.6 lb/(lbf⋅h)); Cruise: 23.1 g/(kN⋅s) (0.815 lb/(lbf⋅h))
  * Thrust-to-weight ratio: 4.914
  