Lyulka AL-21
# Lyulka AL-21

The Lyulka AL-21 is an axial flow turbojet engine created by the Soviet Design Bureau named for its chief designer Arkhip Lyulka.

## Design and development

The AL-21 is closely similar in technology to the General Electric J79 first flown in 1955, which was the first engine for supersonic flight, using a variable stator.

It is generally described as being in the "third generation" of Soviet gas turbine engines which are characterized by high thrust-to-weight ratios and the use of turbine air cooling.

The AL-21 entered service in the early 1960s. Later designed the AL-21F3, it was used in the Sukhoi Su-17, Sukhoi Su-24, Ground-attack variant Mikoyan-Gurevich MiG-23, and Sukhoi T-10 (Sukhoi Su-27 prototype).

## Specifications (AL-21F3)

**General characteristics**

* Type: Afterburning turbojet
* Length: 5,300 mm (209 in)
* Diameter: 1,000 mm (39 in)
* Dry weight: 1,700 kg (3,740 lb)

**Components**

* Compressor: Two-spool 14-stage axial compressor with variable stator vanes
* Turbine: Two-stage high pressure, single-stage low pressure

**Performance**

* Maximum thrust:
* 76.4 kN (17,175 lbf) dry
* 109.8 kN (24,675 lbf) with afterburner
* Overall pressure ratio: 14.75:1
* Turbine inlet temperature: 1,100 °C (2,000 °F)
* Specific fuel consumption:
   * 77.5 kg/(h·kN) (0.76 lb/(h·lbf)) at idle
   * 87.7 kg/(h·kN) (0.86 lb/(h·lbf)) at maximum military power
   * 189.7 kg/(h·kN) (1.86 lb/(h·lbf)) with afterburner
* Thrust-to-weight ratio: 4.6 maximum military power / 6.6 with afterburner
* Life expectancy: 1,800 hours
