Su-27 Air-Superiority Fighter Aircraft
Avionics and Systems
The Su-27 fighters in service with the PLAAF are equipped with the NIIP Tikhomirov N001E Myech coherent pulse Doppler radar with track-while-scan and ‘look-down/shoot-down’ capability. The radar has a maximum search range of 240km, and a target engagement range of 80~100km in the forward hemisphere and 40km in the rear hemisphere for a fighter-sized target. The radar has the capacity to search, detect and track up to ten aerial targets with automatic threat assessment and prioritisation.
Additionally, the aircraft's infrared search and track system, laser rangefinder, radar, and helmet-mounted target designator provide detection, tracking and attack capability. The OEPS-27 electro-optic system consists of the OLS-27 infrared search-and-track (IRST) sensor collimated with a laser rangefinder. The OLS-27 sensor is placed forward of the cockpit canopy in the centre. The system acquires and tracks aerial targets by their thermal signatures. The range of the electro-optical system is 40~100km, depending on the aspect angle presented by the target. For better close air combat performance, the pilot is assisted by a RLPK-27 helmet-mounted sight (HMS). The HMS and the laser range finder of the IRST can also be used to visually acquire and determine coordinates of air and surface targets.
The SEI-31 integrated indication system provides flight, navigation and sighting data on the ILS-31 head-up display (HUD) and CRT. The EW self-defence systems provides warning to the crew when illuminated by enemy radar and employs both passive and active countermeasures. The aircraft is equipped with the SPO-15 Beryoza RWR and APP-50 IR decoy dispenser. Chaff dispensers are placed in the tail section between the engine nozzles. In addition, the aircraft can carry the Sorbtsiya active jamming ECM pods on its wingtips.
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| RLPK-27 helmet-mounted sight (Chinese Internet) |
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| OEPS-27 infrared search and tracking system and the head-up display (Chinese Internet) |
Armaments
The fixed weapon includes a GSh-301 30mm cannon fitted internally with 150 rounds of ammunition. The aircraft has ten external hardpoints (2 tandem under the fuselage centerline; 2 under the air ducts; 4 under the wings; 2 on the wingtips) to carry up to 8,000kg weapon payload.
For visual-range air-to-air combat, the Su-27 is equipped with the then revolutionary Vympel R-73 (NATO codename: AA-11 Archer) IR-homing short-range air-to-air missile. Coupled with the aircraft’s RLPK-27 helmet-mounted sight (HMS), the missile poses a serious threat to any modern fighter in close-in combats. For beyond-visual range (BVR) combat the aircraft is equipped with the R-27 (NATO codename: AA-10 Alamo) semi-active radar-homing medium-range air-to-air missile, in both long and short burn variants.
In a typical interception mission, the aircraft carries four R-73 and six R-27 missiles. Alternatively, the aircraft could carry two R-73 missiles, six R-27 missiles, and two KNIRTI SPS-171/L005 Sorbtsiya active jamming electronic countermeasures (ECM) pods on the wing-tips for self-defence.
The Su-27 was originally designed as an air-superiority/interceptor fighter, with ground attack only as a secondary role. The aircraft currently does not possess the capability of delivering precision-guided weapons. When used for ground attack missions, the Su-27 carries free-fall bombs and unguided rocket launchers. The PLAAF was frequently spotted using the Su-27 fighter this type of mission in exercise, a practice which would expose the expensive fighter unnecessarily in combat.
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8 |
6 |
4 |
10 |
1/2 |
9 |
3 |
5 |
7 |
Internal:
GSh-301 (150 rounds) |
AAM:
R-73 (AA-11)
R-27ER
R-27ET |
1X |
1X |
1X
1X
1X |
1X
1X |
2X
2X |
1X
1X |
1X
1X
1X |
1X |
1X |
Ground Attack:
FAB-500/RBK-500 500kg bomb
FAB-250 250kg bomb
B-8MI/B-13L/S-25 rocket launcher |
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2X
6X
2X |
1X
6X |
2X
12X |
1X
6X |
2X
6X
2X |
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| A PLAAF Su-27 carrying four R-27/AA-10 MRAAMs, two R-73/AA-11 SRAAMs, and wingtip ECM pods (Chinese Internet) |
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| Two PLAAF Su-27SKs firing unguided rockets at the ground targets in exercise (Chinese Internet) |
Modernisation
Russian Kommersant online daily newspaper reported on 27 November 2006 that two Russian engine manufacturers, Salut Moscow Engineering Production Enterprise and Rybinsk Saturn, were competing to supply the engines to upgrade China’s Su-27 Flanker fighter aircraft. This was also the first report to have revealed the PLAAF’s intension to upgrade its Su-27 fleet.
According to the report, Salut offered its AL-31F-M1 turbofan engine, which is an improved variant of the AL-31F on the original Su-27. The AL-31F-M1 model features increased thrust (from 122.58kN to about 133kN with afterburning) and capacity. The engine was intended to be used to upgrade the existing Su-27/30 series fighter aircraft. The Al-31F-M1 development was completed in 2002. Upon approval of this upgrade package by Sukhoi, the engine is now being prompted to existing and future customers of the Su-27/30 series fighter.
Saturn proposed its latest 117S engine developed from the AL-31FP, which is being used to power the Indian Air Force’s Su-30MKI fighter. Though the 117S engine is more technologically advanced compared to AL-31F-M1, it’s development has yet been completed and the engine is still undergoing tests.
The PLAAF received its first and second batch of Su-27 fighters from Russia in 1992 and 1996 respectively. After a decade of service, these aircraft apparently began to show their age. Kommersant report suggested that the PLAAF planned to purchase 52 engines worth US$180 million to upgrade 26 Su-27 fighters (20 Su-27SKs and 6 Su-27UBKs) in 2007 to 2008. This may followed by additional engines to upgrade 22 Su-27 fighters (16 Su-27SKs and 6 Su-27UBKs) at later stage. Both companies believe that the PLAAF will eventually have to upgrade all of its 273 Sukhoi fighters (Su-27, Su-30, and J-11) with the new engine, extending the overall contract budget to US$2 billion.
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