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There is no argument within the defense community that
America needs a new family of military aircraft. The problem
is money. Keeping one step ahead of the former Soviet Union
has driven the cost of aircraft to astounding heights. The
U.S. Air Force says that the "fly-away" cost of the first 10
F-22 Raptors, the last fighters designed to counter the Soviet
threat, is $99.7 million each. When the U.S.S.R. folded its
tent, the Pentagon decided it was time not only for new
planes, but also for a less costly way of doing business. And
that has birthed America's newest combat aircraft, the F-35
Joint Strike Fighter (JSF).
The F-35s are a family of three aircraft, designated the
F-35A, F-35B and F-35C. Similar in shape and size, and powered
by the same basic engine, the F-35s will share between 70 and
90 percent of their parts. Yet, under the skin they are three
distinctly different machines.
The U.S. Air Force will fly the F-35A. Designed to take off
and land from conventional runways, it bears a close family
resemblance to the F-22 Raptor air superiority fighter--a
trait shared by all three JSF variants. The Air Force wants to
use the F-35A to replace its obsolete fleet of A-10 tank
killers and rapidly aging F-16 fighters. "The [F-35A] would
allow for migration by U.S. forces to an almost all-stealth
fighter force by 2025," says Edward Aldridge, undersecretary
of Defense for Acquisitions.
In a future war, F-22s and F-35As would fly complementary
missions. The F-22 would establish and maintain air
superiority, while the F-35As would attack the enemy on the
ground. Planners envision that during the first hours of a war
F-35As would take advantage of their near Mach 2 speed and
stealth to deliver a pair of internally carried 2000-pound "supersmart"
bombs against command and control targets. Once the enemy was
blinded and stealth became unnecessary, ground crews could fit
the two hardpoints on the F-35As wings with a variety of
missiles and bombs. If the Air Force holds to its current
plans, it will buy 1763 F-35As. The least complicated of the
designs, they will cost more than $30 million each.
U.S. Marines will fly the F-35B, which is detailed in the
cutaway drawing to the right. While its overall shape, size
and radar-absorbing stealth coatings are identical to the Air
Force F-35A, the powerplant and airframe have been modified
for short takeoff and vertical landing (STOVL) operation. The
Marines will use the F-35B to retire their current--and
rapidly dwindling--fleet of British-designed AV-8B Harrier
jump jets. F-35Bs would be deployed with Marine Expeditionary
Units and operate off short-runway landing ships. Eventually,
the Marines hope to buy 609 F-35Bs to replace the Harriers, as
well as their carrier-based F/A-18C/D Hornets.
The Navy will fly the most visibly different member of the
JSF family, the F-35C. Built using the same airframe and
engine as the Air Force and Marine variants, it will have
larger wing and tail-control surfaces. These are needed to
maintain control at the lower speeds required for carrier
approaches. The wingbox and airframe will be strengthened to
absorb the shock of catapult launches and arrested landings.
Additional wing area--which is created with larger
leading-edge flaps and foldable wingtip sections--means the
F-35C will be able to carry more fuel for a longer operating
range and a larger payload. The Navy hopes to buy 480 of the
aircraft to replace its aging fleet of Hornets. In a future
war, the F-35Cs would work in concert with the F/A-18E/F Super
Hornets.
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The F-35 is the product of an aggressive aircraft design
competition that pitted the nation's two top military aircraft
manufacturers, Lockheed Martin and Boeing, in a corporate
dogfight.
Each company was required to build and fly its
version of the JSF, designated the Boeing X-32 and Lockheed
Martin X-35. But that was only the start. With the JSF project
the Pentagon not only wanted a superior aircraft, it also
wanted to pull in the reins on escalating costs. To put this
strategy into action, manufacturers were instructed to design
planes with as many common parts as possible. Beyond designing
and building an aircraft, each company also was required to
demonstrate that its design would be the most economical for
the armed forces to operate. In the end, the task of selecting
a contractor for the "winner take all" contract proved so
complex that some 250 Defense Department officials were
involved in evaluating the data. "Both of the proposals were
very good. Both demo programs were very good," says James
Roche, secretary of the Air Force. "It became clear, as we
went through this process, that the Lockheed Martin team was a
clear winner from the point of view of best value for the
government. I would not characterize [the decision] as a
squeaker at all, nor would I say by a mile."
Lockheed Martin's design represents a blend of old and bold
technologies. The F-35 achieves its stealthy, small radar
cross by relying heavily on an airframe and engine inlet
design that borrows liberally from the F-22 Raptor, also built
by Lockheed Martin. Initially, F-35s will use a modified
version of the Pratt & Whitney F119 engine that powers the
F-22. The F-35's engine is designated the F135. If the F-35
goes into full production, all three versions of the aircraft
also could use a direct-replacement F120 engine, to be built
by General Electric.
The F-35 makes its most radical departure from the past
with the choice of the lifting system for the F-35B jump jet.
The Harriers currently operated by the Marines achieve
vertical flight by diverting downward the hot gases expelled
by the engine. The F-35B uses a design built around a lift
fan. Lifting with cooler air offers several advantages. Chief
among them are less heat stress on the engine and a smaller
infrared signature for anti-aircraft missiles to home in on.
The tradeoff is a higher degree of mechanical sophistication.
There are three parts to the lifting system. The first part
is the lift fan. About half of the thrust needed to hover and
land is created by forcing ambient air downward through a pair
of doors that open directly behind the cockpit. Power comes
from a 2-stage low-pressure turbine on the engine and is
coupled to the lift fan through a clutch. The fan itself
consists of a pair of counterrotating turbines that are
capable of creating as much as 18,000 pounds of thrust.
Roughly the same amount of thrust is created by blasting hot
gases from the engine downward, through a 3-bearing nozzle,
the system's second part. Finally, a pair of roll nozzles
located under the wings, provide balance.
Thus far, the Defense Department has committed $22.9 billion
for the construction of 22 F-35s. The Air Force and Marines will
each get five flying aircraft, the Navy four. The remaining
eight will be non-flying versions for various testing programs.
The Pentagon estimates it will eventually need as many as 3000
F-35s, at a total cost of $200 billion. The British government,
which has been involved with the JSF project since the inception
of the program in the mid-1990s, has expressed interest in
buying either the F-35B or F-35C. A final decision is not likely
until 2010 when, among other things, the prices of these
aircraft can be estimated with greater certainty.
Barring a wholesale shift to unmanned vehicles or
unanticipated engineering problems--both viewed as unlikely
events--the F-35A will begin replacing the Air Force F-16s and
A-10s by 2010. The following year, the Marines and Navy will
take delivery of their first F-35Bs and F-35Cs. 
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