stealth technology
“Stealth no longer applies
to just fighters. Everything
has to be able to operate
in a contested airspace.”
In an effort to reduce the radar surface wave – a
single pulse of which would travel along the entire length
of a fuselage – before returning to its ground source.
Facets with non-perpendicular corners were added to an
airframe, which meant radars looked at them along their
diagonals instead, often at low angles and across the
facets’ smallest angles, which limits the area of edgewave
emission.
At high relative frequencies, surface waves can also
be suppressed with RAM. Shapes composed of blended
facets are not only more aerodynamic but also allow
current to smoothly transition at their edges, reducing
surface-wave scattering. Blended bodies have the
potential for a lower RCS than the original faceted
designs, especially at low-frequency regime. Blending
the curves around an aircraft in precise mathematical
manner reduces the RCS around the azimuth plane by
an order of magnitude. The penalty is often a slight
widening of the specular return at the curves, but in
directions at which threat radars are less likely to be
positioned. This was one of the great discoveries of the
second-generation of stealth technology.
For those nations unable to afford to build a complete
stealth aircraft, elements of the blended design technique
were added to their four-generation fighters, such as in
the forward ventrally-mounted intake on Eurofighter/
3
42 SEPTEMBER 2019 \\ AEROSPACETESTINGINTERNATIONAL.COM
Typhoon, which features a
curved intake ducting with
rounded edges. Although
nowhere near as effective
as a fifth-generation
platform, it’s seen as the
best compromise for an aircraft developed under
a complex European partnership arrangement.
SIXTH GENERATION STEALTH
With the need to maintain a potent viable air threat,
many nations such as Turkey, France, Japan and the UK
have jumped a fighter generation. Several
sixth-generation designs have been publicly unveiled at
airshows. Unsurprisingly, most resemble Lockheed’s
F/A-22 Raptor. But Dassault Aviation’s chairman and
CEO, Eric Trappier, stresses that its next generation of
manned fighter, the SCAF (Système de Combat Aérien du
Future) program, which is overseen by France, Germany
and Spain will incorporate stealth.
“By far the most important factor is to integrate
stealth technology by keeping the new fighter as
maneuverable as possible for air dominance. But also, it
must be able to deploy stealth developed weapons such
as new smaller cruise missiles, which have stealth
capabilities that are being developed,” says Trappier.
US$68bn
Cost of F-22
development
3 // The F-22 Raptor is an
example of how angled
surfaces and internal
shaping are used to
suppress the reflections
from re-entrant structures
such as engine intakes and
antenna cavities, reducing
reflections towards the
emitting radar so that they
are rarely perpendicular to
radars (Photo: USAF)
4 // A computer-generated
concept of the Tempest
fighter entering contested
airspace at low-level
(Image: BAE Systems)
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