China's J-20 stealth jet has taken to the skies - but Indian Air Force (IAF)says its fighters can spot it easily

China recently made history as the first country besides the US to field stealth aircraft with its J-20 fighter. But IAF says its Russian-made Su-30MKI fighter jets can spot the supposedly-stealth J-20s. Unlike the US's F-22 and F-35 stealth jets, the J-20 doesn't have all aspect stealth.

China recently made history as the first country besides the US to field stealth aircraft with its J-20 fighter, but reports from its regional rival, India, indicate that it may want to go back to the drawing board.

As per a news report, Indian Air Force Chief Marshal Birender Singh Dhanoa said the "Su-30 radar is good enough and can pick it (J-20) up from many kilometres away."

India has been basing its Su-30MKIs in the northern part of the country to counter China's deployments of J-20s, which struggle to take off in the high altitudes near Tibet. The Su-30MKI represents a new and effective Russian jet with an advanced array of radars that could probably spot the J-20 Sputnik News reported.

It is entirely possible that the Su-30MKI can pick up track information on J-20 from quite long ranges. But those tracks may be fairly intermittent and dependent on what headings the J-20 is flying on relative to the Sukhoi trying to detect it.

Unlike the US's F-22 and F-35 stealth jets, the J-20 doesn't have all-aspect stealth. This means that from some angles, the J-20 isn't stealthy, however, the J-20 is stealthiest from the front end.

If China was flying the J-20s in any direction besides towards India, the Su-30MKI radars could have been spotting the jets from their more vulnerable sides.

Also, it is possible that the Chinese are flying the J-20 with radar reflectors attached to enlarge and conceal its true radar cross section during peacetime operations - just as the USAF routinely does with the F-22 and F-35.

For safety and training purposes, stealth aircraft often fly with markers that destroy their stealth during peacetime manoeuvres. If this is the case with the J-20s, then India may be in for an unpleasant surprise next time it tries to track the supposedly stealth jets.

What Radar Reflectors Do

Radar Reflectors (more accurately called Radar Target Enhancers, or RTEs) reflect radar energy from other radars so that your plane shows up as a larger and more consistent “target.” Inherently, it means that in areas where low visibility is common the ability to be seen by radar-equipped sources can make the difference between being seen and being crashed. But the same technology could be used by adversaries into believing their fighter jets could be easily detected.

How they work

RTEs work by reflecting radar energy directly back to the radar antenna so that your aircraft appears to be a larger target. The best analogy we can think of is the reflective “dots” on many highways that make it so much easier to see where the lanes are. These light reflectors use small triangular-shaped prisms that bounce the light around and reflect it precisely back at its source.

The effectiveness of an RTE is disproportionately related to its size. Assume that you have three theoretical reflectors of the same design, but of different sizes. Look at how rapidly the RCS (Radar Cross Section) increases with size. The RCS of a given reflector goes up by the fourth power of the radius, resulting in this dramatic increase in effectiveness. For example: a reflector of twice the size of a similar but smaller model has a RCS that is 16-times larger. (With inputs from Sputnik News & West Marine)

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