Monday, 29 October 2012

Super Su-30MKI: From Air Dominance To Air Supremacy

Come 2012 the first batch of 50 Sukhoi Su-30MKI multi-role combat aircraft (MRCA), which were delivered to the Indian Air Force (IAF) between 2001 and 2003, will be shipped back to Russia’s IRKUT Corp in Irkutsk where they will be refurbished and upgraded from into formidable air supremacy MRCAs (to be called Super Su-30MKI), and delivered back to the IAF starting 2014. The upgrades, costing Rs109.2 billion, will include the strengthening and service life-extension of the Su-30MKI airframes; and installation of uprated turbofans, new glass cockpit avionics, mission management avionics, and integrated defensive aids suites. This will be followed by another batch of 42 new-build Su-30MKIs to be subjected to identical upgrades, with deliveries of these aircraft beginning in 2015 and ending in 2018. It is expected that in future the Su-30MKMs of Malaysia and Su-30MKAs of Algeria too will be subjected to such ‘deep’ upgrade programmes.

The airframe strengthening programme for the 50 Su-30MKIs, when completed, will enable each of the 50 Su-30MKIs to carry two 290km-range underwing BrahMos supersonic multi-role (land-attack and maritime strike) cruise missiles (which itself is presently undergoing a weight reduction exercise), and also accommodate two uprated Lyulka AL-31FP turbofans. The AL-31FP, presently rated at 126kN with afterburning, will offer 20% more power when uprated by NPO Saturn—its manufacturer--and will have a total technical service life of 6,000 hours, instead of the present 2,000 hours. The uprated engine will also employ a larger diameter fan, redesigned key hot-end components and cooling system technologies to permit reduced thrust lapse rates with altitude, which in turn will permit supercruise flight regimes. Also to be incorporated into the uprated engine will be new-generation full-authority digital engine controls (FADEC) as well as all-axis thrust-vectoring nozzles (±15 degrees in the vertical plane and ±8 degrees in the horizontal plane, with deflection angle rates of up to 60 degrees per second). The digital flight-control computer too will be replaced to achieve harmonisation of the digital flight control laws associated with supercruise and all-aspect supermanoeuvrability.

The glass cockpit avionics package, developed by Russia’s Avionica MRPC and Tekhnocomplex Scientific and Production Centre, will include new-generation hands-on-throttle-and-stick (HOTAS) controls made by KB Aviaavtomatika, panoramic active-matrix liquid crystal displays, and a compact OLS infra-red search-and-track sensor developed by the Ekaterinburg-based Urals Optical & Mechanical Plant. The mission management avionics package will include dual redundant core avionics computers developed by the Defence Research & development Organisation’s (DRDO) Bangalore-based Defence Avionics Research Establishment (DARE) and built by Hindustan Aeronautics Ltd (HAL). The integrated defensive aids suite, now being developed by a joint venture of DARE and Cassidian of Germany, will include the MILDS AN/AAR-60 missile approach warning system (MAWS).

The open-architecture IDAS has been under joint development by DARE and Germany-based Cassidian since 2006, and will include the AAR-60(V)2 MILDS F missile approach warning system, the EW management computer and Tarang Mk3 radar warning receiver (developed by DARE and built by Bharat Electronics Ltd), a countermeasures dispenser built by Bharat Dynamics Ltd, TsNIRTI-developed expendable active electronic decoys, a reusable fibre-optic ABRL active radar towed-decoy using suppression, deception and seduction techniques, and an internal EW suite supplied by Elettronica of Italy (the very same Virgilius suite that is on board the MiG-29UPG). The Virgilius family of directional jammers, which are also used by the Eurofighter EF-2000, make use of active phased-array transmitters for jamming hostile low-band (E-G) and high-band (G-J) emitters, and is considered an equivalent of the AESA aperture-based jammers of THALES’ Spectra EW suite. The ABRL can be deployed manually from the cockpit, or automatically upon threat detection. It provides active interference to the terminal guidance of incoming air combat/surface-to-air missiles in order to provide for an increased miss-distance to outside lethal range. The ABRL features four rear-mounted lattice control fins to provide for decoy control and providing a certain amount of drag for enhanced stability during extreme manoeuvring. The advantages of lattice controls are that they can be folded down to facilitate carriage (in this application) inside a compact launch tube, are capable of unstalled operation at up to 50-degree angles of attack, and significantly reduce the demands placed on their actuators. In essence, they provide a great deal of lifting area despite having a very small chord, so combine outstanding effectiveness with comparatively small hinge moments. In the ABRL, the lattice fins are hinged forward into a recess in the decoy body and deploy rearwards upon decoy deployment.

The principal on-board mission management avionics components of the upgraded Su-30MKIs will be the multi-mode MIRES X-band active electronically steered-array (AESA) multi-mode radar (MMR), developed and built by the V Tikhomirov Scientific-Research Institute of Instrument Design along with Ryazan Instrument-Making Plant Federal State Unitary Enterprise, and modular L-band and S-band transmit/receive (T/R) modules that will be housed within the Su-30MKI’s forward wing and wing-root sections, as well as on the vertical tail sections. The MIRES, using the back-end elements of the Su-30MKI’s existing NO-11M ‘Bars’ PESA-based MMR, will be able to simultaneously perform up to five ‘core’ functions, comprising look-up and shoot-up; look-down and shoot-down; directional jamming of hostile data-links; real-beam ground mapping via Doppler-beam sharpening in the inverse synthetic aperture radar (ISAR) mode; and ground moving target indication. This will give the Super Su-30MKIs an unprecedented degree of all-round situational awareness and interleaving mission synchronicity (performed by the two-man crew), which will be available, for the most part, from only the F/A-18 Super Hornet’s International Roadmap variant once it becomes available from 2013 onwards. 

The MIRES radar’s GaAs-based RF components (transistors, diodes and MMICs) have been developed and made by Moscow-based NPO ‘Istok’. The wing-/tail-mounted L-band or S-band T/R modules will be employed for secondary airspace surveillance, as well as for missile approach warning and directional jamming of airborne tactical data-links associated with BVRAAMs and AEW & C platforms, thus transforming the upgraded Su-30MKI into a combined airborne early warning/tactical battlespace management platform. With operating in wavelengths of between 6 and 12 inches, L-band permits good long-range airspace search performance with modestly-sized antennae, while providing excellent weather penetration and reasonably well-behaved ground clutter environments, compared to shorter wavelength bands. The basic L-band modular AESA array design and its integration into the leading edge flap structure have already been flight-certified. The physical alignment of the array is with the leading edge of the wing, at 42 degrees for the Su-30MKI’s airframe. Each array will employ 12 antenna elements. Three quad T/R modules each drive four antenna elements, for a total of 12 elements per array, in three sub-arrays. The linear array is embedded in the leading edge of the wing flap, with the geometrical broadside direction normal to the leading edge. The leading edge skin of the flap covering the AESA is a dielectric radome, which is conformal with the flap leading-edge shape. The array geometry produces a fan-shaped main lobe, which is swept in azimuth by phase control of the 12 T/R modules, providing a two dimensional volume-search capability. The arrangement of the AESA produces a fan-shaped beam, which is swept in azimuth to cover a volume in the forward hemisphere of the aircraft. The distributed AESA arrays (X-band, L-band and an optional S-band) are nothing less than the ‘shared multifunction aperture’ model now very popular in the design of Western X-band AESA-based MMRs, including the Raytheon APG-79 and Northrop Grumman APG-80. However, the greatest advantage of such on-board distributed AESA arrays is that they will convert the Su-30MKI into a mini-AEW & C platform capable of undertaking tactical airborne battle management tasks in support of offensive air campaigns deep within hostile airspace, thereby doing away with the need for dedicated AEW & C platforms, which could then be more gainfully employed for strategic airspace surveillance-cum-management. Thus far, the IAF has projected a requirement for 50 Su-30MKIs to be configured as mini-AEW & C platforms.

Other new-generation avionics to be installed on the Super Su-30MKI will include the RAM-1701AS radio altimeter, TACAN-2901AJ and DME-2950A tactical air navigation system combined with the ANS-1100A VOL/ILS marker, CIT-4000A Mk12 IFF transponder, COM-1150A UHF standby comms radio, UHF SATCOM transceiver, and the SDR-2010 SoftNET four-channel software-defined radio (working in VHF/UHF and L-band for voice and data communications), and the Bheem-EU brake control/engine/electrical monitoring system, all of which have been developed in-house by the Hyderabad-based Strategic Electronics R & D Centre of Hindustan Aeronautics Ltd (HAL). The digital air data computers and flight data recorders and their automated test benches will be supplied by Bengaluru-based SLN Technologies Pvt Ltd.

For air dominance operations the upgraded Su-30MKI will be armed with two types of new-generation air combat missiles from Vympel JSC: the RVV-MD within-visual-range missile, and the RVV-SD beyond-visual-range missile. The RVV-MD’s maximum range is 40km (the existing R-73E has 30km range) and comes equipped with a two-colour imaging infra-red sensor that has +/-60-degree off-boresight tracking capability. The manoeuvre controls are aero- and gas-dynamical. The maximum angle-of-attack is significantly higher than that of the R-73E, and can hit targets that are manoeuvring at 12 G. The RVV-SD has a maximum range of 110km and engage targets flying at an altitude of 25km. Equipped with both laser-based and contact fuzes, the RVV-SD has a 22.5kg warhead, mass of 190kg, length of 3.71 metres, diameter of 0.2 metres, and wingspan of 0.42 metres. It too can engage targets manoeuvring at 12G. The guidance system is inertial for the middle course, with radio-correction and a jam-resistant active radar for the terminal phase.

Like the existing Su-30MKIs, the upgraded models too will be equipped with COBHAM's 754 buddy-buddy refuelling pod (20 units have already been delivered to the IAF to date), Elbit Systems’ Condor 2 LOROP pod, IAI/ELTA’s ELM-2060P ISAR pod, and RAFAEL’s Litening-3 laser designator pod. To date, India has ordered a total of 272 Su-30MKIs, with deliveries continuing till 2018. Thus far, about 120 Su-30MKIs have been delivered to the IAF. These are presently deployed with the Lohegaon, Pune-based No2 ‘Winged Arrows’ Sqn, No20 ‘Lightnings’ Sqn, No30 ‘Rhinos’ Sqn and No31 ‘Lions’ Sqn; Bareilly-based No24 ‘Hunting Hawks’ Sqn; Tezpur-based No8 ‘Pursoots’ Sqn; and No102 ‘Trisonics’ Sqn at Chabua.

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