Stealth is a technology of invisibility. The stealth technology is very important in military. The first stealth aircraft, ever commissioned in the world, is the F-22 Raptor of United States of America. It is a dream technology. The flight is the fifth generation one, ie, with supersonic speed and of course, with stealth technology.

China, yesterday has announced its first successful flight of its stealth aircraft CHENGDU J-20 and its probable induction into air force in next 8 years.

Let us discuss about Stealth technology. The stealth aircrafts evade detection by RADARs. RADARs, normally use the cosmic radiation, or micro waves to detect the flying objects over a particular geographical area. The obstruction caused by the flying objects on the path of the microwaves, cause the waves to reflect, and the reflection is observed by the ground station of the RADAR.  With the time duration of the wave reflection, we can calculate the speed of the flying object, altitude, its path etc and accordingly we can initiate our defence mechanisms.

The objects with stealth technology evade the RADARs by not showing any obstruction in the beam of waves. Is it possible? It is actually impossible because, to evade the detection the aircraft should be transparent, like glass. If the flying object absorb all the radiation, still it may look like a dark spot in the RADAR monitor. 

Therefore the outer walls of the aircraft is covered by micro bumps. (like you find them, when you purchase a Fridge, or TV, as it is covered by plastic sheets with air bumps). The bumps will scatter the incoming radiation, so that the ground station may not receive the obstruction signal. The bumps are designed so that to scatter the incidental waves upwards.  The outer wall is coated with a special paint which absorbs some of the radiation.

But these technologies are not sufficient to achieve stealth. It is completely achieved when he flying object sways at supersonic speeds. These days, USA is researching on stealth of earth movers also, Tanks. 

India, also claims that it has achieved 60% of stealth of flying objects. We may reach this feet very soon. Anyway, let us congratulate China for its first successful stealth flight.