Douglas Barrie/MOSCOW

RUSSIAN RADAR design house NIIP has revealed that it is testing a phased-array radar for the Sukhoi Su-35 advanced derivative of the Su-27 Flanker.

At the Moscow air show, NIIP showed an image of a fixed-array antenna mounted to the nose section of a variant of the Su-27. Part of the aircraft's code number was visible, possibly indicating that this is Su-35 aircraft 711, although the paint scheme differs from that in more recent images of the aircraft.

NIIP says that the phased-array radar was built at its Zhukovsky site near Moscow. The radar was first fitted to the aircraft in 1992/3.

The NIIP radar previously associated with the Su-35 programme uses a slotted array flat-plate antenna (see picture), and was shown fitted to what appeared to be aircraft number 709. NIIP was the design house responsible for the Mikoyan MiG-31's Zaslon phased-array radar, and the Su-35 radar is built on this experience.

NIIP says that the slotted-plate and phased array radar represent "different modifications" of what it calls the N-011, with the latter bearing the N-011M designation.

The radar house also suggests that it is looking at marrying the phased array with a mechanical system to provide a moving phased-array antenna.

Rival radar manufacturer Phazotron, also claims to be working on phased-array radar for the Su-35, dubbed the Zhuk-PH. It is uncertain whether this is a completely different design, whether it draws on the NIIP antenna, or whether the two are collaborating.

NIIP suggests that the first Su-35s will be fitted with the slotted-array radar, while later aircraft will be fitted with a variant of the phased-array antenna. The exact status of any production order from the Russian air force for the Su-35 remains uncertain.

It adds that flight testing of the phased-array radar is about to begin, suggesting that the mating of the radar illustrated may have only been a "form-and-fit" trial.

Besides being intended for the Su-35, NIIP says that the radar will also be offered for Su-27s, Su-30MKs, and Mikoyan's fifth -generation fighter, the 1.42.

NIIP confirms that it has held talks with Indian officials concerning the radar for the Sukhoi Su-30MK, which the Indian air force is interested in procuring. The Su-30MK may be fitted with the N-011M.

Source: Flight International