India’s Quest For A Stealth Fighter

J-20 Stealth Fighter
J-20 Stealth Fighter
When China displayed the prototype of its first ever stealth aircraft ,
the J 20 in 2010 it sent alarm bells ringing not just in the US but more
importantly in countries across East and South East Asia. China has
now joined the foremost ranks of fighter-building nations, setting off a
debate in the West and among China’s immediate neighbors over if and
when the J-20 might begin entering service in great numbers and how that
may shape the Asia Pacific balance of power. Suddenly countries ranging
from Japan to South Korea to Indonesia decided to jump into the stealth
bandwagon and co develop Low Observable fighters with foreign partners.
Since the mid nineties backers of F 22 and F 35 fighters which rely on
stealth have utilized simulators and conferences to uphold the idea
that stealth will be an overpowering advantage in air combat.
 We can
probably take a deep dive and understand stealth fighter programs of
other Asian countries sometime in the future, however for the time being
I will focus on something that is more close to our heart – When will
India get it’s stealth fighter aircraft ? As we know, India has started
work in right earnest with it’s “strategic partner” Russia to develop a
Low Observable or stealth fighter aircraft. In this regard it’s worth
asking an important question. Is it worth having a stealth aircraft ?

Isn’t it true that the F 22 has never been tested and the Serbs shot
down a F 117 using similar X band radars. After Russia introduced the
low band radars, especially operating in the VHF band isn’t it now
possible to detect and shoot down any stealth fighter before they can do
any damage. Most stealth design features are intended to scatter
incoming illumination in a controlled fashion. The prerequisite for this
to work is that the wavelength be much smaller than the basic
dimensions of the shaping feature of relevance. Therefore, for stealth
aircrafts to counter VHF band radar the wavelengths must be of the order
of a metre or more, which today only the B 2 has (however it is not a
fighter aircraft). A fighter sized aircraft such as the F 22 or F 35
will see most of its cautiously designed shaping features fall into the
resonance where shaping is of little or no import, and skin depth
penetration of the induced electrical surface currents defeats most
absorbent coatings or laminates. To answer this question let us take a
close look at the PAK FA program. The PAK FA already comes with a
forward looking large nose mounted X band AESA, side looking smaller X
band AESA radars, and wing mounted L band AESA radars, multi spectral
IRST, front and back looking IRSTs. Going by the prototype it seems that
extreme maneuverability has been given precedence over all aspects of
stealth so the PAK FA may not carry out the deep penetration role of the
F 22. My understanding is that the PAK FA has been designed from the
onset to detect the F 22 or similar stealth aircrafts from a long
distance using it’s IRST and then destroy these aircrafts in a Within
Visual Range conflict.

Obviously, designing the avionic suite of the PAK FA is not going to be
easy for Sukhoi. The provision of high capacity avionic cooling, which
does not produce infrared hotspots, and in the design of wideband, yet
very low RCS radio-frequency apertures for both passive and active
sensors (similar to the F 22s Agile Beam), and aircraft datalink/network
terminal transceivers. Unlike the F-22, which uses stealth technology,
85 percent of the surface of PAK FA is covered with unique nano
technological materials that decrease both the visibility of the plane
and air drag.

Proper stealth needs to be a factor from the very start of the design
stage because every aspect of the design will influence the final radar
cross section.There are two aspects that are important with stealth and
they are shaping and materials absorption. Shaping means designing the
reflecting surface to redirect radar waves coming from any direction in
any direction other than the direction the energy came from. Materials
absorption means materials that absorb radio waves. Having a composite
radar invisible skin is pointless. They currently use dielectric nose
radomes that cover the nose. Mounted radar are invisible to radar
otherwise the radar inside them would not work through them. Making the
outer skin of a plane out of that material would just make the insides
of the plane visible to the radar and all that external shaping to
redirect radar so that it doesn’t return to the radar antenna would be
completely wasted.There is no reason why the PAK FA needs to use all the
same methods to reduce RCS that the F-22 or any other aircraft uses.

The PAK FA will not be some miracle plane, but it renders obsolete all
Euro canards in a single step and renders Meteor pretty useless because
with its IR sensors the PAK FA will be able to spot Meteor from quite a
distance and will be able to fly “around” it. Even when it turns on its
radar scanner its reduced detection range means the PAK FA pilot need
never let it get close enough to see him and that is assuming the Rafale
or Typhoon even sees him in the first place to launch. The stealth
aircrafts of adversaries (like the J 20) on the other hand will be up
against an aircraft using L band radar in wing mounted AESA antenna
arrays, plus the latest in IIR sensors. A simple data link connection
between a flight of 4 Su-30MKIs and they could synthesize an L band
antenna thousands of metres in length which should be able to spot J
20’s or even B2’s at extended distances. Stealth is worth it as long as
it doesn’t completely compromise everything else. Otherwise one
breakthrough and you are a sitting duck with your very expensive white
elephant.

Therefore, we shouldn’t think of stealth as a be all and end all. Rather
we should think of stealth as a type of ECM. It means that even if
they have long wave radars that will tell them roughly where you are
they no longer have the option of a long range shot with a BVR missile
because the stealth effect has reduced its detection range enough to
make it near useless as a fire and forget weapon. Being able to see a
target is only half the problem, you have to be able to hit it with
something.


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