How the Russians reduced the RCS of the big bad Su-35 (Su-27M)

[Yongpeng Sun-Tastaufen]

Russian stealth researchers have developed materials and techniques that can reduce the head-on radar cross-section (RCS) of a Sukhoi Su-35 fighter by an order of magnitude, halving the range at which hostile radars can detect it. The research group - working with Sukhoi, but based at the Institute for Theoretical and Applied Electromagnetics (ITAE) at the Russian Academy of Sciences in Moscow - has performed more than 100 hours of testing on a reduced-RCS Su-35 and has also experimented with the use of plasmas - ionized gases - to reduce RCS.

"A problem of huge size" is how the researchers describe the Su-35 inlet, with a straight duct that provides direct visibility to the entire face of the engine compressor. The basic solution has been to apply ferro-magnetic radar absorbent material (RAM) to the compressor face and to the inlet duct walls, but this involves challenges. The researchers note: the material cannot be allowed to 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 that meet these standards. A layer of RAM between 0.7mm and 1.4mm thick is applied to the ducts and a 0.5mm coating is applied to the front stages of the low-pressure compressor, using a robotic spray system. The result is a 10-15dB reduction in the RCS contribution from the inlets.

The modified Su-35 also has a treated cockpit canopy which reflects radar waves, concealing the high RCS contribution from metal components in the cockpit. ITAE has developed a plasma-deposition process to deposit alternating layers of metallic and polymer materials, creating a coating that blocks radio-frequency waves, is resistant to cracking and crazing and does not trap solar heat in the cockpit. The plasma-coating process is then carried out robotically in a 22 m3 vacuum chamber.

ITAE and its partners have also developed plasma-type technology for applying ceramic coatings to the exhaust and afterburner. The conference video also showed the use of hand-held sprays to apply RAM to R-27 air-to-air missiles.

https://www.fighter-planes.com/stealth2.htm

 

[Yongpeng Sun-Tastaufen]

Of course, because of law of conservation of energy, radar absorbing material must absorb radio waves and convert that to heat, raising the temperature of the aircraft. Fortunately, radio waves are fairly long wavelength so very weak and little heat is produced after absorbing it.

Similar features can be found on F-22 which reduces reflectance of radio waves, reduces RCS.

A good way to reduce frontal RCS is by using DSI type air intakes.

Because the DSI bumps are round, they greatly scatter incoming radio waves and therefore ensures that much less of the incoming radio waves pass through the bumps and reach the engine blades.

However, because Russia failed to developed DSI technology, Su-35 (Su-27M)'s frontal RCS is roughly comparable to that of JF-17 which has bumps.

 

[Yongpeng Sun-Tastaufen]

@pakistanipower

 

[Ultima Thule]

However, because Russia failed to developed DSI technology, Su-35 (Su-27M)'s frontal RCS is roughly comparable to that of JF-17 which has bumps.

What the fcuk @undertakerwwefan they can't reduce the size of air intakes and used only composite materials and expect they change Frontal RCS to JF-17 are they using anti physical alien On Su-57 and in SU-35 @undertakerwwefan