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Updated: Sun Aug 29 16:43:38 UTC 2010
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APA NOTAMS ISSN 1836-7135
When America’s Stealth Monopoly Ends,
What's Next?
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Air Power
Australia - Australia's Independent Defence Think Tank
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Air Power Australia NOTAM
4th March,
2009
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| Contacts: |
Peter
Goon
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Carlo
Kopp
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Mob:
0419-806-476 |
Mob:
0437-478-224
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PAK-FA rendering by NPO
Saturn. Unlike the JSF, the stealthy PAK-FA is being designed with air
superiority performance and high agility as the primary consideration.
To date only speculative renderings have been released, making
assessments difficult (Saturn NPO).
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For three decades the United States has
held the undisputed monopoly on the most important military technology
of the Cold War era - stealth. That monopoly is set to end over the
coming decade as the Russians, Indians and likely Chinese deploy
a new generation of military aircraft designs. Available to any client
with the cash, these high technology products will obsolete the large
fleets of legacy Cold War equipment the West has relied upon since the
end of the Cold War to maintain global stability, as well as rendering
the planned
F-35 Joint Strike Fighter impotent.
A world in which any nation with the cash can procure stealthy manned
or robotic aircraft, or cruise missiles, will be very different from
the
world we see now. Many of the fundamental assumptions made about
America’s hitherto undisputed strategic primacy will collapse, unless
Americans take stock now and start seriously planning for this future.
The Russians have two stealth aircraft designs in the current
development pipeline, intended to be deployed operationally between
2010 and 2020. The Chinese are claimed to be working on a stealthy
follow-on to the J-10 Sinocanard fighter, and have displayed models of
supersonic stealthy unmanned vehicle designs.
The first of the two Russian designs is an unmanned robotic strike and
reconnaissance vehicle, similar in concept to the US X-45 and X-47
UCAV/UCAS designs. One of the mockups, designed by the MiG bureau, was
shown to Western media in 2007, and is designated the SKAT (skate).
This ten tonne vehicle is a “batwing” design with a planform modelled
on the US B-2A bomber, but less refined detail shaping compared to
existing US designs.
The second of these designs is the PAK-FA (Перспективный Авиационный
Комплекс Фронтовой Авиации - Future Aviation System For Tactical
Aviation), a multirole tactical fighter intended to compete with the
F-22A Raptor in the air, and with the F-35 Joint Strike Fighter in the
marketplace. The PAK-FA will replace the Russian Sukhoi Flanker series
as the primary fighter in the Russian Air Force, and will become the
principal export fighter for Russia’s booming defence industry.
The prototype of the PAK-FA was intended to fly in 2008, but has been
delayed to this year, so to date no useful imagery of this design
exists. The Russians have made numerous public statements which do
provide some indication of what the design aims for this aircraft are:
it is intended to be stealthy, highly agile to prevail in close air
combat, it is intended to be fitted with an evolution of the 20
kiloWatt class NIIP N035 Irbis E phased array radar, and to be powered
by a pair of 35,000 lbf class supersonic cruise turbofan engines.
On paper, these cardinal parameters put the PAK-FA in the class of the
F-22A Raptor.
The first question any observer will properly ask is whether the
Russians have the basic technology to design, develop, test and produce
a credible state-of-the-art stealth fighter. The key technologies
required for this include shaping design techniques, absorbent material
and coating techniques, digital flight control technology, rectangular
engine nozzle technology, engine hot end technology, and Low
Probability of Intercept (LPI) digital radar and networking technology.
Shaping techniques are the most important prerequisite technology for
stealth design - their purpose is to scatter radar waves illuminating
an aircraft away from the threat radar. Good examples of smart shaping
design include the F-117A, B-2A, YF-23A and F-22A Raptor, as well as
the proposed FB-22A. The F-35 Joint Strike Fighter engine nozzle and
lower fuselage
areas are examples of
especially poor shaping design .
Effective shaping techniques permit an aircraft to be built with a 100
to
1,000 fold lower radar signature compared to a conventional design of
similar size.
The two principal tools required to perform proper rigorous shaping
design are computer based simulation tools, typically based on physical
optics, diffraction and surface travelling wave mathematical modelling,
and measurement tools and test range facilities to verify that shapes
designed on a computer actually work as intended.
With commodity desktop computers now outperforming the supercomputer
technology used by US defence contractors during the 1970s and 1980s,
and Russia’s surplus of high quality PhD graduates in mathematics,
physics and electrical engineering, the ability of Russian industry to
produce good stealth shaping design is limited only by the investment
made in personnel, measurement tools and test ranges. As the SKAT UCAV
mockup shows, current Russian design technique is converging on US
design technique.
What is often forgotten in the West is that Russian designers have a
long history of cherry-picking the best ideas from extant Western
designs, incrementally improving them, and fusing them together to
produce an end product that outperforms its Western predecessors.
Classic examples include the AS-4 and AS-6 supersonic cruise missiles,
improving on the British Blue Steel, or the Sukhoi Flanker, which fused
key ideas from the US F-14, F-15 and F-16 fighters to produce an
original new design outperforming all three US fighters.
With a wealth of imagery available detailing the US F-117A, B-2A,
A-12A, YF-23A and F-22A Raptor, the Russians have a defacto library of
sound and well proven ideas to work with. There is no need for Russian
industry to
reinvent the wheel, as US engineers have paved the way with a wealth of
creative thinking.
Driving the signature of a stealth aircraft down further, into the size
of tennisballs, golfballs and marbles, is done by the application of
radar absorbent structures, materials coatings, and low signature
seals, fasteners, antennas and other detail components.
Russian industry has a long history of creative and original
developments in coating technologies and materials science. Recent
disclosures include a coating which reduced the radar signature of the
engine inlet tunnels in the Su-35BM Flanker by a factor of 30 in the
centimetre radar band. Other technologies the Russians have developed
include multilayer laminates which rotate the polarisation of surface
travelling waves to suppress trailing edge reflections.
The Russians mastered digital flight control technology during the
1990s and have been using it in the supermanoeuvrable Su-30MKI/MKM,
Su-35BM and MiG-35 designs, to an advantage. There is sufficient
maturity in this technology now to make a highly manoeuvrable stealth
fighter, not unlike the F-22A.
The technology of rectangular exhaust nozzles used in all proper US
stealth designs to control radar and infrared signatures, is also well
within the reach of Russian industry, which trialled a rectangular
thrust vectoring nozzle during the early 1990s.
In terms of engine technology, the Russians built the Al-41F
supercruise engine during the 1990s and since then migrated its hot end
technology into the Al-31F-117S for use in the Su-35BM. A 35,000 lbf
class supercruise engine for the PAK-FA is therefore a non-issue.
In radar the choice of mature Russian hybrid phased array technology
for the PAK-FA over immature active array technology is a short term
measure. It took US radar designers a decade to transition from the
quad module technology used now in Phazotron’s Zhuk-AE to current
single channel module technology. By 2020, probably sooner, the
Russians will have mastered this, emulating US designs. That technology
will permit the addition of the wideband frequency hopping techniques
and stealthy antenna arrays, which characterise current US Low
Probability of Intercept (LPI) AESA radars and top end datalinks.
The most recent generation of Russian radars use fully digital
processing chains, which opens up the full gamut of sophisticated
processing algorithms, which have appeared in US radars during this
decade.
There can be no doubt that the Russians possess all of the basic
technologies required to design an F-22 class supercruising and agile
stealth fighter - the basic aerodynamic, shaping and propulsion design
of the F-22 was performed over a decade ago.
When the PAK-FA is unveiled later this year we will see exactly how
effective Sukhoi’s design engineers have been in fusing these
technologies
together to produce a new design. We can be confident that the design
will be an effective supercruiser and it will be highly agile. The only
uncertainty at this stage is in how stealthy it will be.
How stealthy does the PAK-FA need to be to defeat US legacy fighters? A
radar cross section of only -20 dBSM would deny early Beyond Visual
Range (BVR) missile shots using the AIM-120C/D AMRAAM to all current
and planned US fighters. Doing any better, like -30 dBSM or -40 dBSM,
simply increases the level of difficulty in prosecuting long range
missile attacks.
The consequence of this is that missile combat will be compressed into
shorter distances and shorter timelines, putting a premium on the
stealth, supersonic persistence and close combat agility of US
fighters. A larger portion of engagements will be at visual range, and
most BVR engagements will end up taking place inside 30 nautical miles.
Only the F-22A Raptor is viable in an air combat environment where the
PAK-FA is deployed, and the F-22A will not provide a 144:0 kill ratio
against the PAK-FA.
The F-35 Joint Strike Fighter struggles to survive against the
conventional Su-35BM Flanker, with only its -30 dBSM class front sector
stealth keeping it alive in some BVR combat situations. Against even a
-20 dBSM class PAK-FA, the F-35 falls within the survivability black
hole, into which US legacy fighters such as the F-16C/E, F-15C/E and
F/A-18A-F have already fallen.
Americans need to start thinking about which strategic niche they wish
to occupy in 2020. The stealth monopoly cannot last forever, and the US
must now confront the prospect of a future in which the asymmetric
advantage of US stealth is no longer absolute, but rather incremental.
There is a big difference, operationally and strategically, in using
stealthy jets against opponents who have none, versus using stealthy
jets against opponents who also use stealthy jets. Incremental
differences in stealth performance will matter, but much less in
such “symmetric” stealth vs. stealth conflicts, compared to past
asymmetric conflicts.
The most fundamental and immediate conclusion is that US planning for
the future of its fighter fleet must be architected around the F-22A
Raptor and improved future derivatives, since only this aircraft will
be survivable in a future globalised market for stealthy combat
aircraft.
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Air
Power
Australia
Website - http://www.ausairpower.net/
Air Power Australia Research and
Analysis - http://www.ausairpower.net/research.html
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