Howard Gethin/LONDON

Sukhoi is to offer South Korea an enhanced version of the Su-35 fighter, equipped with the NIIP NO-11M phased-array radar, 1553digital databus and a cockpit featuring multifunction colour displays and a sidestick control column, following recent test flights of a new Su-37 multirole demonstrator - the T10M-12.

Sukhoi has offered South Korea a licence for partial assembly of the Su-35 from Russian components, 100% local servicing and technology transfer, according to Russian media sources. The Sukhoi proposal also includes offsetting the cost of the aircraft against Russia's large debt to South Korea.

The economic downturn in Asia has caused a slowdown in South Korea's F-X fighter programme. A request for proposals was expected in July, but the programme is unlikely to get under way before 2000.

The test aircraft, number 712, will soon be fitted with Lyulka Saturn AL-31FP thrust vectoring engines, which are now under test on two Su-30MK fighters.

The T10M-12 has so far not been shown publicly and is undergoing trials alongside the two Su-30MKs with AL-31FP engines. Increased thrust AL-31FMs are reported to be under development.

Flight tests of the AL-31FPs began on the second prototype Su-30MK on 23 March, according to Su-27M programme manager Vladimir Konokhov. The nozzles are vectorable as in previous AL-31 derivatives, but move in the horizontal, not vertical, plane. The engines are mounted at a 32¼ off-vertical angle, so that the nozzles can move in intersecting planes, giving an X-shaped vectoring path when viewed from astern. The nozzles are driven by the aircraft's flight control system, giving enhanced manoeuvrability in combat.

Increased use of titanium has reduced the weight of the nozzle significantly, as well as doubling the service life from 250h to 500h.

The Ufa Motor Building plant has begun producing 88 AL-31FP engines for India's 40 Su-30MKI multirole fighter. The Su-30MKs already delivered to India are equipped with earlier non-thrust vectoring engines, which will be replaced by the AL-31FP. The final prototype Su-37, with a complete fire-control system and avionics of all-Russian manufacture, together with AL-31FP engines, is to be shown at the Paris air show in 1999, according to Konokhov.

Source: Flight International