The general American mentality of considering every Non-American weapon as inferior has led to downplay of Su-57 by western media.
American and Russian philosophy of designing & developing weapons platform has always been different. Americans preferred a digital platform for Network Centric Warfare, with primary focus on Beyond Visual Range (BVR) combat where long range air to air missiles are guns & close combat heat seeking missiles are its bayonet. Gun on the platform (fighter aircraft) itself is nothing but “the lessons from Vietnam”.
On contrary Russians always went for a sweet medium & believing the fact that close combat will never end with latter being sensible. “With every offensive technology comes the defensive technology”. Su57 was developed with this principle in mind. In case of Stealth– Su57 is least stealthy among all the operational stealth fighters viz. F-22, F-35 & J-20. The designers at Sukhoi went for a balanced approach. It has reduced RCS
(Radar Cross Section) and is stealthy enough to force its adversaries to come closer to engage and get detected by its own detection systems.
Stealth aircraft are not invisible to radar as the mainstream media calls them. They appear too small to be considered as a target, for example an F-35 appears to be of size of a golf ball and is able to fool the radar but is not practically invisible. Modern radars are able to detect fifth generation stealth fighters– distance at which they are detected depends upon the capabilities of that Radar and RCS of the target aircraft.
In a hypothetical situation lets say a particular Radar is able to detect a 4th Generation F-5C Eagle at a range of approximately 200 km, that same radar will detect F-35 at 30 km and F-22 at range of say 20 km, the detection range depends upon the RCS of aircraft (the above figures are just examples). The aircraft will be detected come what may, the distance at which it gets detected can be a game changer.
Su-57 carries its primary N036 Byelka X-Band AESA Radar conventionally in its nose section, what makes it different are the two smaller side mounted X-Band AESA radars on its cheek just below the cockpit. This allows enhanced situational awareness to the pilot. Side mounted radars can be helpful to guide an in-flight missile while beaming. Beaming is a classic defensive technique used to break a missile lock by getting into the radar’s doppler notch. Radars work on principle of doppler shift to track the target. In a nut shell a radar on a fighter jet can track its target if its moving towards or away from the radar, if the defensive aircraft (the target) takes a turn in such a way that the angle between the radar and the target is approximately 90 degrees then the radar is not able to track it. The defensive aircraft can dodge the incoming missile but it cannot target the attacking aircraft either, the two side mounted radars on Su-57 comes in handy while beaming. Su-57 can go into the defensive beaming and can acquire the attacking aircraft and guide its missile at the same time. It also incorporates an X-Band AESA Radar in its tail section. Three radars in forward fuselage and one in its tail provide the pilot with profuse amount of situational awareness.
The leading edge extension on Su-57 also has an L-Band radar. Most 5th generation fighters are designed to remain stealth in X-Band, the L-Band radar on Su-57 has a potential to detect 5th generation stealth aircraft.
It seems like the designers at Sukhoi intentionally gave up on the stealth. The 101KS Atoll Electro Optic Suit comes with 101KS-V IRST (Infra Red Search & Track) placed on the starboard side (right side) on the aircraft in front of the cockpit– not an ideal position to keep aircraft stealthy. But since IRST’s are integral component of Russian fighter design philosophy they are included in Su-57 as well even if comes at the cost of increased frontal RCS. IRST’s are passive devices that can detect heat signature, even 5th generation aircraft like F-22 & F-35 have massive heat signatures & cannot conceal themselves from IRST. IRST’s can also guide in-flight air to air missiles towards its target. It can perform all above activities while remaining electromagnetically silent i.e not emitting radio waves. But unlike radars IRST’s don’t have higher detection range. F-22 was supposed to receive IRST, but due to cost cutting measures it was scrapped.
In addition to IRST, 101KS Attol EO Suit also has 101KS-O DIRCM (Directional Infrared Countermeasure). DIRCM have been used in past but due to their size they were exclusive to larger platforms such as transport helicopters and fixed wing cargo planes. But Su-57 has a miniaturized DIRCM on its dorsal (top) as well as ventral (bottom) section & it is first of its kind. DIRCM’s are used as a defense against heat seeking missiles, they fire laser beams towards the missile’s seeker and blinds it.
Read: The next generation F-16
The Russian reluctance to let go the dog-fighting skills is evident from their Su-57. An aircraft with limited stealth or low observability, state of the art L-402 Gimalai Electronic Counter Measures, IRST, DIRCM, thrust vectored engines gives it an overwhelming advantage in visual range & near visual range fight– a capability no other aircraft has.