One
of the main competitors for this replacement program is the Lockheed Martin F-35 Lightning II. The aircraft is described as a “5th Generation fighter, combining advanced
stealth with fighter speed and agility, fully fused sensor information,
network-enabled operations and advanced sustainment.”
For
many the most important part of the proceeding description is “stealth”. It is
the attribute which seems to set the F-35 apart from all its
contemporaries. So just what is the big
deal about Stealth?
It
has never been easy to convey what low observable technologies actually do.
Understanding them requires some grasp of physics, of radar phenomenology, of
aircraft design, and of how missions are planned and executed. Rebecca Grants’ paper “The Radar Game”, issued by the Mitchell Institute in 2010,
is still one of the most accessible discussions of the subject available.
The
point of Stealth is to reduce an object’s detectability across the
electromagnetic spectrum but most importantly to radar. In this case the goal is to minimize the
electromagnetic energy reflected back to radar so that the signal cannot be
used for fire control solutions.
Traditional
aircraft are vulnerable to radar detection for all the reasons that increased
their aerodynamic qualities and performance in the first place. That is things
like metal skins, large vertical control surfaces, and big powerful engines.
There
is also a wider electromagnetic spectrum to consider. While radar is the main
focus here, survivability can depend on taking measures to reduce visual,
acoustic, and infrared signatures as well as minimizing telltale communications
and targeting emissions.
Among
passive technologies the favorite is infrared search and track. While
it is not as often in the headlines as radar, designers of all-aspect stealth
aircraft have worked since the 1970s to minimize infrared hotspots on aircraft.
It
is also true that electronic countermeasures will have a role to play. It will always take a combination of
survivability measures to assure mission accomplishment.
It
is important to remember that the goal of ‘Stealth’ is not to make an aircraft
invisible. For example, it may be difficult to prevent a blip on the kinds of
long-range, low frequency radars used for initial detection, however it takes
much more than a blip on a “Tall King” radar to unravel a well-planned mission.
An aircraft designed to be stealthy in relation to radar gains advantages in
how close it can come to air defense systems; it does not get a free pass in
the battlespace.
Having
said all that, it is essential to understand the advantages, and limitations,
that radar stealth can grant.
Aviation Week & SpaceTechnology
has analysed, using open source material, the relative advantages of various
aircraft in relation to radar cross section.
They suggest that,
based on figures released by the manufacturer, that the Su-35 can detect a 3-m2
target at 400 km (250 mi.). Keep in mind
that large “fourth-generation” fighters such as the F-15, Su-27 and Tornado
have radar cross-sections (RCS) of 10-15 m2. The F-16 and “Gen-4.5”
fighters—Typhoon, Rafale, Su-35 and Super Hornet are believed to be in the
1-3-m2 range. Of course the figure is
larger if external stores are carried.
The F/A-18E/F,
which Boeing says employs the most extensive RCS-reduction measures of any non-stealth
fighter, is reported at 0.66-1.26 m2
Based on these figures, A.W. & S.T. estimates
that aircraft such as the F-15, the Tornado or Su-27 would be detected at a
range of 335 to 370 miles (540 to 600 kilometers). Aircraft such as the F-18,
F-16, Su-35 and Typhoon would register at ranges of 185 to 200 miles (300 to
400 kilometers).
On the other hand
the F-35 and F-22 RCSs are said to equal a golf ball and marble, respectively
which means that the Su-35 cannot detect an F-35 until it is within 36 mi. and
inside 22 mi. for an F-22. And the U.S. fighters can launch their medium-range
AIM-120 AMRAAMs from more than 60 mi. away. Also, that detection range is for a
maximum-power, narrow-angle search. In conventional search mode, the detection
range is half as much.
As Aviation Week
& Space Technology points out in that article, the same arguments can
be applied to the efficacy of stealth aircraft in relation to ground based air
defence systems.
The
latest S-400 surface-to-air system is feared for many reasons, including its
longest-range (380-km) missile, but it cannot fire until its Gravestone radar
has a target. According to the manufacturer that radar can detect a 4-m2
target at 250 km (155 mi.). This is good against “reduced RCS” fighters, but
the F-35 would not be seen until 21 mi. away and the F-22 13 mi. away. The kind
of internally carried Small Diameter Bombs used by these aircraft can be
dropped from more than 40 mi. away.
Given
these figures it can be argued that stealth aircraft will have an advantage
over the kinds of weapons systems current fielded by our potential opponents. A
contrary conclusion would be that if “fourth generation” aircraft were to be
provided with longer range weapons they could just as easily overcome those
systems.
Complex
technologies like stealth cost money to field and the price of excellence is
nothing new. The premier US night fighter of late World War II was the P-61
Black Widow. Its power and performance came with a high price however. It
is reported that with
Northrop’s assembly line in full gear, a completely equipped P-61 cost $180,000
in 1943 dollars, three times the cost of a P-38 fighter and twice the price of
a C-47 transport.
High
technology still carries a substantial price tag; the question for the Canadian
Fighter Replacement Program therefore becomes, will stealth aircraft pay back
the investment in combat value? The answer to that question is a big deal indeed.
Replacing
Canada’s CF-18 Fleet
F-35
Lightning II
The
Radar Game
Measuring
Stealth Technology's Performance
Conquering the
Night Army Air Forces Night Fighters at War - Stephen L. McFarland
