Voici un article assez interessant paru dans le Journal of Electronic Defense:PolluxDeltaSeven a écrit : D'ailleurs, il me semblait que les Russes avaient plus ou moins émi l'idée de laisser tomber le développement d'une furtivité passive, trop couteuse et longue à développer, au profit d'une technologie basée sur le pasma...
Vu l'imaturité de cette technologie à l'époque (il y a une demi-douzaine d'années), je trouvait ça plutôt douteux (ou ambitieux!).
Quelqu'un sait si c'est toujours d'actualité??
Russian Stealth Research Revealed
Bill Sweetman
January 2004
Russia shows solid progress in a variety of low-observable technologies
Russian research into low-observable (LO) technology has remained largely secret, despite the collapse of the Soviet Union and the semi-privatization of the aircraft industry. However, a newly published paper from the Institute for Theoretical and Applied Electromagnetics (ITAE) at the Russian Academy of Sciences (Moscow, Russia), presented at the International Quality and Productivity Center’s conference on stealth, held in London in October 2003, shows that Russian researchers have made solid progress in key technologies for LO aircraft and have test-flown some technologies — such as the use of plasmas to protect targets from radar — that are not known to have been studied in the West.
In the paper, entitled “Stealth Technology: Fundamental and Applied Problems,” Russian stealth researchers claim to have reduced the head-on radar cross-section (RCS) of a Sukhoi (Moscow, Russia) Su-35 fighter by an order of magnitude, halving the range at which hostile radars can detect it. The research group has performed more than 100 hours of testing on a reduced-RCS Su-35. According to other reports, the ITAE has demonstrated similar technology on a MiG-21bis, and it has been offered to India as part of a MiG-21 upgrade package. Similar modifications have been made to Western aircraft (such as the Have Glass package developed for the F-16), but it is not known whether they claim the same level of performance.
Russian investigators certainly have the basic scientific knowledge to apply stealth to aircraft. Some of the basic mathematical and optical theories that underlie stealth originated in Russia (such as Ufimtsev’s theory of edge diffraction), and some of the most significant early work on reducing the RCS of military vehicles was carried out by Russian warship designers. The Kirov-class battlecruisers — with a 22° “tumblehome” angle imposed on normally vertical bulkheads, screens, and skirts to shield high-RCS components from radar, along with extensive use of radar-absorbent material (RAM) — were remarkably stealthy despite their size. “If you saw a big wake with nothing in front of it,” British marine LO expert Peter Varnish has said, “you knew you’d found the Kirov.”
There is also an LO strand in Russian aircraft design. The Tupolev (Moscow, Russia) Tu-160 Blackjack bomber is a reduced-signature design reminiscent of the B-1 Lancer. Sukhoi has designed a series of supersonic bombers with low-profile, highly blended configurations. In early 2000, Russian military leaders considered that a new, stealthy medium bomber would be the next major Russian military aircraft project, to replace the Tu-22M.
Most current Russian military aircraft show little evidence of stealth in their design, but that is not surprising, given that they were defined in the early 1970s. The more recent MiG 1.42 and Sukhoi S-32 fighter prototypes were designed as details of US stealth projects became known and, thus, represent a compromise solution. They carry their primary weapons internally, and the Vympel R-77 missile — which corresponds to this generation of aircraft — is designed for internal carriage. However, they do not reflect features found on US designs, such as the careful organization of wing, tail, and inlet edges along a few common alignments. They look like aircraft in which aerodynamics dominate the basic shape, and materials are used to eliminate RCS hotspots — very much the same as the technology described in the ITAE paper.
The dominant contributors to the Su-35’s head-on RCS are the inlets, which the ITAE researchers call “a huge problem.” With a straight duct that provides direct visibility to the entire face of the engine compressor, the inlet might have been designed to advertise the fighter’s presence at the greatest possible range. (Lockheed stealth pioneer Alan Brown’s comment on straight ducts is that “the energy comes romping out like a lighthouse beam.”) The ITAE, though, has developed a high-performance, ferro-magnetic RAM for the compressor face and duct walls. The material has to be thin, because it cannot constrict airflow or impede the operation of anti-icing systems, and must withstand high-speed airflows and temperatures up to 200°C. The ITAE team has developed and tested coating materials which meet these standards. A layer of RAM between 0.7-mm and 1.4-mm thick is applied to the ducts, and a 0.5-mm coating is applied to the front stages of the low-pressure compressor, using a robotic spray system. The result is a reduction of 10-15 dB in the RCS contribution from the inlets — more than halving the RCS.
Like the Have Glass F-16, the modified Su-35 also has a treated cockpit canopy that reflects radar waves. The ITAE has developed a plasma-deposition process to deposit alternating layers of metallic and polymer materials, creating a durable coating that blocks radio-frequency (RF) waves and does not trap solar heat in the cockpit. The plasma-coating process is carried out in a vacuum chamber by a robotic tool.
The ITAE and its partners use plasma technology for applying ceramic coatings to the exhaust and afterburner. Multi-layer coatings formed from microparticles of dielectric, metal, or semi-conductor material are deposited by an arc-discharge plasma under atmospheric pressure. Challenges include the need to keep the ceramic bonded to the metal structure over a wide temperature range (600°C to 1,200°C), despite the fact that the materials have widely different thermal-expansion characteristics. The coating materials also need to maintain constant electrical characteristics in the face of widely varying temperatures. Researchers describe this problem as “partially solved,” and engines treated with ceramic RAM have already been flight-tested.
Video at the conference also showed the use of hand-held sprays to apply RAM to R-27 air-to-air missiles. There is no point, researchers say, in reducing the RCS of the airframe unless the reflectivity of external weapons can be reduced as well.
The ITAE has flight-tested a unique and exotic technology to mask the Su-35’s huge 35-inch radar antenna: the use of a low-temperature, “plasma-controlled screen.” The screen is mounted in front of the antenna and is transparent to radar when switched off]
en cherchant des infos sur le F-22 j'ai trouve ca : 
Mais c'est bien pour ç]
