The first jet fighters appeared at the end of World War II. A
few of them, equipped with machine guns, saw combat and quickly proved that
jets were here to stay. During the Korean War, faster, more heavily armed
fighters entered service, including the first supersonic air-to-air dog
fighters and the first to carry only missiles as
weapons.
Photo courtesy U.S.
Air Force
The F/A-22 is an air-superiority fighter with improved
capability over current Air Force aircraft.
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Today, powerful fighter aircraft are basically flying
computers that combine technology and stealth design to be invisible to
enemy radar and attack their opponents without warning. We'll look at the
newest fighter in the U.S. Air Force's aerial arsenal, the F/A-22 Raptor.
The "F/A" designates the Raptor as a "fighter" and an
"attack" aircraft. As we'll see, the F/A-22 incorporates the
latest approaches to avoiding detection along with a mind-boggling array of
weapons and technology to succeed at both missions.
What is the F/A-22 Raptor?
The F/A-22 is the world's first stealth air-to-air fighter, designed
to be unseen at long range and deadly in close-in air combat. It can also
strike ground targets with precision accuracy. Its design gives pilots
unmatched maneuverability in the air.
The F/A-22 was originally designed to replace the F-15 Eagle. Because of
the Eagle's versatility, the rising cost of developing the F/A-22 and the
changing world scene, the Raptor now supplements the F-15 instead of
replacing it. When the F/A-22 program began in the early 1980s, the Air
Force wanted a fighter to counter the threat from the Soviet Union. Since
the end of the Cold War, the need for an air-superiority fighter has
fallen: Pentagon war planners expect future conflicts to be fought against
enemies with small air forces or none at all.
Photo courtesy U.S.
Air Force/John Rossino
Employees at the Lockheed Martin assembly plant paint the
first operational F/A-22 Raptor to be delivered to the Air Force.
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F/A-22
Specifications
- Primary
Function: Fighter, air-dominance
- Wingspan: 44
feet 6 inches (13.5 meters)
- Length: 62
feet 1 inch (18.9 meters)
- Height: 16
feet 5 inches (5 meters)
- Powerplant:
Two Pratt & Whitney F119-PW-100 engines capable of supercruise and
thrust vectoring
- Speed: Mach
1.8 (supercruise: Mach 1.5)
Three of America's largest defense contractors -- Lockheed
Martin, Boeing and Pratt & Whitney -- joined together to develop and
produce the F/A-22.
In the following sections, we'll learn more about the
technology that makes the F/A-22 the best fighter in the skies.
Stealth Capability: The Basics
Once the stuff of sci-fi speculation and rumors, stealth capability came
into the limelight with the F-117
Nighthawk and the B-2 Stealth
Bomber.
Radar
works by sending radio waves out from an antenna and collecting the waves
that bounce back from any objects (see How Radar Works). On
a radar screen in an aircraft or in a ground-based radar station, an
airplane appears as a blip. The larger the aircraft, the larger the blip
appears on the screen. Other objects, such as flocks of birds, can also
show up. Aircraft designers have worked for years to minimize the radar
signature of an aircraft. If the radio waves are deflected or absorbed so
they don't return to the radar antenna, then the airplane is invisible or
could be mistaken for a flock of birds or other non-threatening object.
Aircraft designers use irregular sawtooth edges, a jumble of
curved surfaces and other design tricks to deflect radar waves in
unexpected patterns. Planes are painted with thick paint that can absorb
radar waves instead of reflect them. The idea is to make the aircraft
appear to disappear into thin air.
Stealth Capability: The Raptor
The F/A-22 incorporates all the lessons learned from previous aircraft. It is
so stealthy that it appears to be the size of a bumblebee when detected by
radar, even though it is more than 62 feet long and has a wingspan of 44.5
feet.
Raptor vs. Nighthawk
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The angular shape of the F/A-22 is similar to the F-117
Stealth Fighter. Many of the surface shapes are curves with changing radii.
These curves scatter radar beams in all directions instead of back to the
radar source. There are no right angles on the exterior of the design.
Sawtooth edges on cockpit edges, landing gear doors and other openings also
break up radar. The edges of the main wing and rear wing line up exactly,
making them appear much smaller on radar.
Photo courtesy U.S.
Air Force
An F/A-22 Raptor climbs on a test mission.
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The F/A-22 has two large vertical fins, much like the F/A-18
and the F-15. On those two aircraft, the straight-up fins contribute to a
high visibility on radar. On the F/A-22, however, the vertical fins are
angled like the body to deflect radar. The fins also conceal internal
antennas that help maintain the invisibility of the aircraft.
The F-22's topcoat absorbs radar waves, too, and the cockpit
was designed to minimize the radar profile of the pilot's helmet.
Tracking the heat from jet engines is
another common way to identify airplanes. Heat-seeking missiles track the infrared
emissions from an airplane's engines to find their target. Blocking
infrared emissions can fool a heat seeker. In the F/A-22, the horizontal
fins at the rear of the aircraft not only make the plane more maneuverable,
but they also act as a shield for the engine exhaust heat. Shielding the
heat of the engines keeps the thermal or infrared signature of the F/A-22
at a minimum.
Unlike current fighters, the F/A-22 can carry missiles inside
the fuselage. The F-15 and F-16, for example, can only carry missiles under
the wings, where they can reflect radar waves and make the plane much more
visible.
The idea behind all this technology is to reduce the enemy's
ability to find, track and target the F/A-22. Pilots can fly into defended
areas that would otherwise be inaccessible to American fighters.
Keep reading to find out about the engine that gives the
Raptor capabilities never before seen in a fighter jet.
Engines: Supercruise
Jet engines use afterburners
to reach supersonic speeds. The afterburner is an attachment on the end of
a jet engine that injects fuel into the exhaust to burn the oxygen left in
the exhaust stream. The afterburner is an easy way to add power for short
bursts, such as take-off or in a dog fight. But the afterburner consumes a
lot of fuel. Fighter jets use the afterburner to fly faster than the speed
of sound for long periods, but it decreases the range they can fly without
refueling.
Photo courtesy U.S.
Air Force
An F/A-22 Raptor in full afterburner during flight testing
at Edwards Air Force Base, CA
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The F/A-22 is the first fighter aircraft with the ability to supercruise,
or fly at supersonic speeds without using the afterburner. In early flight
tests, it sustained speeds of Mach 1.5 -- that's one and a half
times the speed of sound -- without using the afterburner. It can reach Mach
1.8 using the afterburner.
Photo courtesy Pratt
& Whitney, A United Technologies Company
Cutaway of Pratt & Whitney F119 engine
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The Raptor's two Pratt & Whitney F119-PW-100 engines pump
out 35,000 pounds of thrust each (compare that to the 25,000-29,000 pounds
of thrust for each engine on an F-15). Combined with the sleek aerodynamic
design, the engines allow the Raptor to cruise at supersonic speeds with
less fuel consumption than any other aircraft. That means the Raptor can
fly faster for longer periods of time, reaching far-off targets faster than
other jets. It can stay in an area looking for enemy targets longer or
carry a bigger bomb load because it does not have to carry as much fuel.
Engines: Thrust Vector
At the rear of a jet engine, a nozzle directs the flow of hot exhaust gases
out of the engine and afterburner. Usually, the nozzle points straight out
of the engine. The F/A-22's nozzle, on the other hand, is the first vectoring
nozzle. That means the pilot can move, or vector, the nozzle up and
down by 20 degrees.
Photo courtesy Pratt
& Whitney, A United Technologies Company
F-22 engine test: The two blue streams show the up/down
vertical angle the engine can achieve.
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The gases coming out of the vector nozzle help push the
airplane's nose up or down. This vectoring increases the roll rate
of the plane by 50 percent, making it much more maneuverable than other
fighters.
Thrust vectoring is built into the flight control system, so
it works automatically in response to commands from the pilot. When the
pilot turns the aircraft, the nozzle moves in the desired direction along
with the elevator, rudder and aileron control surfaces. The latter three
surfaces are common to all airplanes:
- The elevator
controls the pitch (up-and-down movement) of the airplane.
- The rudder
controls the yaw -- the left-and-right motion along the vertical axis.
- The ailerons
control the rolling motion along the horizontal axis.
With the vector nozzle, the
F/A-22 has a fourth type of control surface.
The F119 engines also give the F/A-22 a high
thrust-to-weight ratio. That means the engines can actually handle many
times the airplane's weight, allowing the plane to accelerate and maneuver
very quickly.
Next, we'll talk about the amazing electronics that make the
F/A-22 seem like a flying video game.
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Raptor Videos
Check out some incredible video footage of the F/A-22 Raptor
in flight:
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Flying Video Game: Behind the Scenes
A modern fighter pilot relies on electronics and instruments to fly and to
find and fight the enemy. Traditionally, those two systems have been
separate in the cockpit, forcing the pilot to manage all the information
separately.
The F/A-22's system was designed to let one crewperson handle
the workload found in two-seat aircraft such as the F-14 Tomcat and the
F-15 Strike Eagle. Its avionics systems are the first to integrate radar,
weapons management and electronic warfare systems into the overall flight
system.
Behind the scenes are two common integrated processor (CIP)
units, the brains of the system. The size of a large breadbox, these units
process all information for sensors and weapons. Currently, only 75 percent
of the CIP's capacity is used, so it can easily take on more duties as
computing requirements in the cockpit grow. There is space for a third CIP
to be installed, allowing for 200 percent growth in capability overall.
Photo courtesy U.S.
Department of Defense
Close-up view of the common integrated processor developed
for the F-22: The CIP is the equivalent of two Cray supercomputers and is
a little larger than a 20-inch television.
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The cockpit is designed to help the pilot use the information
at hand to make decisions quickly in the heat of battle.
Flying Video Game: In the Cockpit
In the F/A-22 computer screens display all information -- it's the first
so-called "all-glass cockpit" in a tactical fighter. These
digital displays have been common in commercial aircraft for years.
Photo courtesy U.S.
Air Force/Tech. Sgt. Kevin J. Gruenwald
F-22 cockpit
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The cockpit is fitted with a hands-on throttle and stick
control (HOTAS). This system allows the pilot to fly the plane without
removing his or her hands from the flight controls. The F/A-22 also has the
first cockpit system compatible with night vision goggles (NVG). A heads-up
display (HUD) projects information in front of the pilot's view,
showing target status, weapon status and cues that indicate if the weapons
are locked on the target. The pilot inputs information for communications,
autopilot and navigation in the integrated control panel (ICP) in
the center top of the instrument panel.
The cockpit has six liquid crystal displays
(LCDs). The primary display is an 8-inch by 8-inch (20.3x20.3-cm) LCD that
provides a plan view of the air and ground tactical situation. This
includes threat identity, threat priority and tracking information. Two
smaller displays show communication, navigation, identification and flight
information. Three secondary displays show air-threat, ground-threat and
stores-management data.
The goal is to make it simple for the pilot to process all the
information being displayed. The pilot can tell at a glance what the
situation is: Enemy aircraft show up as red triangles; friendly aircraft
are green circles; unknown aircraft are yellow squares; surface-to-air
missiles are pentagons. To show that a pilot has a lock on the target, the
red triangle becomes solid. The system is 98 percent accurate in
determining the type of aircraft flying in range. If the system can't make
identification, then the aircraft is shown as an unknown.
Photo courtesy U.S.
Air Force/Kevin Robertson
Four F/A-22 Raptors fly over the Mojave Desert during a
landmark test mission.
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With all that technology onboard, the F/A-22s can create a wireless
data link to share tactical information without talking about it on the
radio. A pilot can
know how much fuel and how many weapons a wingman is carrying while
maintaining radio silence. Multiple flights of planes can link up to
coordinate attacks because each plane can see which targets others have
identified. The F/A-22 can also communicate with Airborne Warning &
Control System (AWACS) aircraft and receive downloads from
reconnaissance planes.
Raptor Radar
The radar system gives the F/A-22 first-look, first-shot, first-kill
capability. That means it can see an enemy plane first, fire a missile and
destroy the target without the other pilot ever knowing about it.
The AN/APG-77
radar was developed specifically for the F/A-22. It uses an active,
electronically scanned antenna array of 2,000 transmitter/receiver modules.
The radar provides pilots with detailed information about multiple threats
before the adversary's radar ever detects the F/A-22.
Also, the radar can jam enemy electronics systems and
communicate voice and data information over a secure link.
Countermeasures
To detect enemy activity, the F/A-22 carries a radar warning receiver
and a missile-launch detector. If an enemy locks on with a
heat-seeking or radar-guided missile, the F/A-22 can launch
countermeasures. It releases flares to confuse heat seekers and sends out
chaff, small pieces of reflective material, to disperse radar waves and
confuse a radar-guided missile's tracking system.
Raptor Weapons
All of this technology serves one purpose: to deliver the F/A-22's weapons
to the target.
Photo courtesy U.S.
Air Force/Judson Brohmer
F-22 launching an AIM-9 Sidewinder missile from its internal
weapons bay.
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Like other stealth aircraft, the F/A-22 can carry weapons
inside the fuselage. The main weapons bay can carry six radar-guided AIM-120C
medium-range air-to-air missiles. If the mission includes ground attack,
two 1,000-pound GBU-32
Joint Direct Attack Munitions replace four of the AIM-120Cs. Two small
bays on each side of the aircraft hold two heat-seeking AIM-9 Sidewinder
short-range air-to-air missiles. Hidden behind a stealth door above the
right air intake is the M61A2
20-mm multibarrel cannon. It holds 480 rounds of 20-mm ammunition and
feeds the gun at a rate of 100 rounds per second.
When stealth is not a requirement, the F/A-22 can carry
weapons and fuel tanks under the wings.
Langley Air Force Base in Hampton, VA, was the first to
operate the Raptor in late 2004. It is scheduled to remain in service
through 2040.
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