stealth

							                           Stealth : The True Miracle of Physics



This isn’t a strange term anymore. Stealth Aircraft or the plane that can ‘vanish’. How such a big
plane like that can vanish? this technology become a true evidence the miracle of physics but so
awesome!

One thingfor sure: this stealth plane technology actually does not vanish at all! But this plane is
difficult to being detected by radar, temperature censor (infrared), and other sophisticated
censor, that also yielded from physics concept. Application of this technology not only limited
to plane, but also to the ships and other vehicle that using electronics device. What physiscs
concept that being a key role technology of the sophisticated plane today?

This is simple! If we look at the mirror (a flat mirror), we can see our image on that mirror. But if
that mirror we oblique to some elevation, our image automatically does not appear anymore.
The only things that appear are the inside surface of the room. It means the lightwave are being
reflected to the direction away from us (not being reflected to our eyes). Why does this
happen?

When the mirror being oblique, the lightwave on our vicinity being reflected (by mirror) to our
eyes so we can see our image on that mirror. The lightwave must be reflected when it collides
on some surface. This principle is being used in radar technology, but the wave that used is not
lightwave, but electromagnetic wave. The reflected wave will be detected by receiver so if
there is the plane’s approaching, we also can know the identity of that plane : velocity,
distance and specification.

The stealth plane can deceive that radar signals! The reflected wave that are supposed to go to
receiver, are difracted to another direction or away from receiver station’s location. This gives
trace that the waves are not reflected at all (only pass around). If there is not reflected wave it
means nothing left on location (the wave not collide on some surface). It’s like elevated mirror
that is aforementioned! The impression is we are not in front of that mirror because the
shadow coming from room surface. Whereas we standby on the same place, that our image
doesn’t occur.


How does the plane’s surface can reflect electromagnetic wave to another direction (not to
receiver one)? With apply plane’s design that have flat surface with plane’s snout that are not
curved like usual planes. Snout’s plane are made to have sharp form. Its above and below are
made flat as possible so that avoid the wave back to receiver. The principle is simple, the
simplest as physics!


Besides snout and surface design, the wing of stealth plane are also made diffrent from usual
planes. If ordinary plane has two wings that supported its weight, the stealth plane usually look
like consist only one wing, without fuselage and tail. Its weight is supported by all plane’s part.
Such design is very helpful to reduce drag force from air that opposite plane’s way direction. It
means the plane can move energetic with high velocity.


A design usually have its weakness, mainly snout and body of the plane. Although that hgas
being calculated precisely, that still can be an electromagnetic wave back to receiver. To reduce
this, all body’s part of plane are wrapped by material called Radar Abrsorbing Material (RAM),
that can absorb electromagnetic wave. It’s similar to the blackbody that absorb heat wave. The
black color is very good in heat absorbing. It can be proved in the middle of the day. We feel
too hot if we use black cloathing because heat wave (infrared) from sun are absorbed all. RAM
are materials like elastromer neoprene and natural rubber that is very good electromagentic
wave absorber. With the combination of body’s design and this RAM will reduce the
possibilities of plane to being detected. In the case of there is signals being detected, it usually
very weak, like signals from birds. It could deceive the receiver station because the intruder will
be considered as the birds.


Besides to avoid radar detection, the stealth plane are also designed to hiding the heat trail
(infrared) that yielded by its engine. This purpose is to avoid missiles tracking that are
programmed to targeting the hottest place with high temperature than its surroundings (heat
seeking missile). The engines that work out is yielded the heat , that can be detected by infared
censor. If its heat profile can be tracked off, so the plane is. The engine of stealth plane lay
down inside on that plane. The hot air from engine is being passed out to cooler so its
temperature will decrease before released to atmosphere. So, infrared censor will not be
detect anything! The engine’s sound will be smooth because the engine is inside (noise from
engine’s operation can be reduce).


But how with its visualization? If the stealth plane are flying around in the middle of the good
day, of course such a big plane could be visible. So that’s why thisplane usually being operate in
the night. It’s accord to the name from stealth plane, for example F-117 is called Nighthawk.
This plane usually has a dark skin that easy to mixed with the environment. In later decades,
this stealth plane are design with chameleon skin, so that it can flying around in the middle of
the day without being visible. Mission Invisible!




Prof. Yohanes Surya Ph.D
http://portal-funphysics.blogspot.com