Published: 7/24/1998

The newly-appointed general director of the AVPK Sukhoi military-industrial complex, Mikhail Pagosyan, who at one time acted as the chief designer for the S-37 Berkut fighter with forward-swept wings, has confirmed that Sukhoi is working on the LFS, the Light Front-line Aircraft. In an interview with Russian journalists, he said, "We have completed a major part of the experimental task on the S-37. That job must be fully completed to provide a firm ground for the creation of future designs. Some of the technologies developed for the S-37 will surely be useful for the LFS. To me, unification of the S-37 and LFS programmes is the right way, leading to a reduction in overall cost of research and development work". It appears that work on the new fighter has not got very far. It is believed that Sukhoi is still at the stage of shaping the LFS. Evidently, Sukhoi is looking at two possible layouts for the LFS: a two-engine variant with Klimov RD-133 engines and a single-engine one with Lulka-Saturn AL-31PF. At the Engines'98 show in Moscow, held on 16-21 June, both of Russia's leading manufacturers of military engines showed their new designs intended for installation on the projected light combat aircraft of the next generation. Lulka-Saturn demonstrated the AL-100, a full-scale model of its new 3-D nozzle for the AL-31 engine, while Klimov had on display a mock-up nozzle for the RD-133. Close analysis of the new moving nozzles revealed an important difference in the approaches to thrust-vectoring. Klimov's design is lighter and simpler, but apparently with higher losses. The moveable part of the nozzle on the RD-133 is supersonic, whereas that of the AL-100 declines both subsonic and supersonic gas flows. Contrary to the existing moveable nozzle on the Su-37 and Su-30MK, the AL-100 moves in both pitch and yaw planes, with the respective maximum deflections being +/-15 and +/-8 degrees. Lulka-Saturn specialists pointed out that the AL-31/AL-100 combination is intended for applications on perspective single-engine aircraft. They explained that to have nozzles moving in pitch and yaw planes is not necessary for twin-engine aircraft: a side force can be easily created by different control inputs to the right and left engines, such as different throttle and nozzle-deflection settings. The AL-100 may be intended for a special version of the S-54 light-weight fighter. This design was conceived as a scaled-down version of the Su-27 for advanced training of fighter pilots. Powered by a single AL-31, the S-54 has gradually evolved from a two-seat trainer into single-seat fighter. Little is known about the current stage of this project, except that the Phazatron company is developing the Sokol radar of the fifth generation, especially for this model. According to Anatoly Kanashenkov, Phazatron general designer, the new radar has a phased-array antenna and a digital signal processor. (DF798.4) (VK)    

Article ID: 224