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.

AI-25
Ivchenko-Progress AI-25TL turbofan engine
Type	Medium Bypass Turbofan
National origin	Soviet Union
Manufacturer	Ivchenko-Progress
First run	1966
Major applications	Aero L-39 Albatros Hongdu JL-8 Yakovlev Yak-40
Number built	9,360+
Developed into	DV-2

An AI-25 from an Aero L-39 Albatros

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.^[1] 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.^[2]

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^[3]

Usage in FP-5 Flamingo Missile

Ukrainian company Fire Point had purchased a large number of Ivchenko AI-25 from various stockpiles, including landfills and dumps for powering the FP-5 Flamingo cruise missile. These engines had a flight time of some 10 hours. Given the engines aren't being used in jet aircraft. Restoring them not to full usage but enough for a Flamingo missile's flight time of three and a half hours. Previous media reports said that the engines had been made by Motor Sich however Fire Point claimed that they had found "thousands of such engines" at various landfills in Ukraine. These engines, in order to keep costs down, have had the titanium parts replaced by "cheaper and easier-to-produce alternatives" to make them flight worthy. Some six thousand of these engines were manufactured and are still in use in aircraft like the L-39 Albatross and Hongdu JL-8 jet trainers in "post-Soviet countries, Asia, and Africa". Fire Point has also established its own plant to produce engines for the missiles, whether this is the Ivchenko AI-25 under licence or not is unclear.^[4][5]

Variants

M-15 powered by AI-25 turbofan engine

AI-25

AI-25A

AI-25TL

AI-25TL series 2

AI-25TLT

(Black Sea Shield - turbofan) The AI-25TLT licence-built by Turkish-Ukrainian joint venture BSS based in Istanbul for the Bayraktar MIUS^[6]

AI-25TLK

AI-25TLSh

AI-25W

AI-25WM

WS-11

(WoShan - turbofan) The AI-25TLK licence-built in China for the Hongdu L-11

Walter Titan

(AI-25WM)^[7]

Walter Sirius

Applications

• Aero L-39 Albatros – (Czechoslovakia)
• Comp Air Jet – (United States)
• Hongdu JL-8 – (China, Pakistan)
• PZL M-15 Belphegor – (Poland)
• Yakovlev Yak-40 – (Soviet Union)
• KB SAT SR-10 – (Russia)
• Bayraktar MIUS – (Turkey)
• FP-5 Flamingo – (Ukraine)

Specifications (AI-25TL)

An Estonian L-39 Albatros in flight powered by an AI-25TL turbofan engine

Data from ^{[8][9][10][11]}

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

See also

Related development

• Lotarev DV-2

Comparable engines

• Garrett F109
• Garrett TFE731
• Williams FJ44
• Ivchenko-Progress AI-222

Related lists

• List of aircraft engines