F/A-18 Hornet is a twin-engine supersonic, all-weather
carrier-capable multirole fighter jet, designed to dogfight and attack ground
targets (F/A for Fighter/Attack). Designed by McDonnell Douglas and Northrop,
the F/A-18 was derived from the latter's YF-17 in the 1970s for use by the
United States Navy and Marine Corps. The Hornet is also used by the air forces
of several other nations. It has been the aerial demonstration aircraft for the
U.S. Navy's Flight Demonstration Squadron, the Blue Angels, since 1986. The
F/A-18 has a top speed of Mach 1.8. It can carry a wide variety of bombs and
missiles, including air-to-air and air-to-ground, supplemented by the 20 mm M61
Vulcan cannon. It is powered by two General Electric F404 turbofan engines,
which give the aircraft a high thrust-to-weight ratio. The F/A-18 has excellent
aerodynamic characteristics, primarily attributed to its leading edge
extensions (LEX). The fighter's primary missions are fighter escort, fleet air
defense, Suppression of Enemy Air Defenses (SEAD), air interdiction, close air
support and aerial reconnaissance. Its versatility and reliability have proven
it to be a valuable carrier asset, though it has been criticized for its lack
of range and payload compared to its earlier contemporaries, such as the
Grumman F-14 Tomcat in the fighter and strike fighter role, and the Grumman A-6
Intruder and LTV A-7 Corsair II in the attack role. The F/A-18 Hornet provided
the baseline design for the Boeing F/A-18E/F Super Hornet, a larger,
evolutionary redesign of the F/A-18. Compared to the Hornet, the Super Hornet
is larger, heavier and has improved range and payload. The F/A-18E/F was
originally proposed as an alternative to an all-new aircraft to replace
existing dedicated attack aircraft such as the A-6. The larger variant was also
directed to replace the aging F-14 Tomcat, thus serving a complementary role
with Hornets in the U.S. Navy, and serving a wider range of roles including
refueling tanker, and electronic jamming platform.
Design
The F/A-18 is a twin engine, mid-wing, multi-mission
tactical aircraft. It is highly maneuverable, owing to its good thrust to
weight ratio, digital fly-by-wire control system, and leading edge extensions
(LEX). The LEX allow the Hornet to remain controllable at high angles of
attack. The wing is a trapezoidal shape with 20-degree sweepback on the leading
edge and a straight trailing edge. The wing has full-span leading edge flaps
and the trailing edge has single-slotted flaps and ailerons over the entire span.
Canted vertical stabilizers are another distinguishing design element, one
among several other such elements that enable the Hornet's excellent high
angle-of-attack ability include oversized horizontal stabilators, oversized
trailing edge flaps that operate as flaperons, large full-length leading edge
slats, and flight control computer programming that multiplies the movement of
each control surface at low speeds and moves the vertical rudders inboard
instead of simply left and right. The Hornet's normally high angle-of-attack
performance envelope was put to rigorous testing and enhanced in the NASA F-18
High Alpha Research Vehicle (HARV). NASA used the F-18 HARV to demonstrate
flight handling characteristics at high angle-of-attack (alpha) of 65–70 degrees
using thrust vectoring vanes. F/A-18 stabilators were also used as canards on
NASA's F-15S/MTD.
The Hornet was among the first aircraft to heavily use
multi-function displays, which at the switch of a button allow a pilot to
perform either fighter or attack roles or both. This "force
multiplier" ability gives the operational commander more flexibility to
employ tactical aircraft in a fast-changing battle scenario. It was the first
Navy aircraft to incorporate a digital multiplex avionics bus, enabling easy
upgrades.
The Hornet is also notable for having been designed to
reduce maintenance, and as a result has required far less downtime than its
heavier counterparts, the F-14 Tomcat and the A-6 Intruder. Its mean time
between failure is three times greater than any other Navy strike aircraft, and
requires half the maintenance time. Its General Electric F404 engines were also
innovative in that they were designed with operability, reliability and
maintainability first. The engine, while unexceptional in rated performance,
demonstrates exceptional robustness under various conditions and is resistant
to stall and flameout. The F404 engine connects to the airframe at only 10
points and can be replaced without special equipment; a four person team can
remove the engine within 20 minutes.
The engine air inlets of the Hornet, like that of the F-16,
are of a simpler "fixed" design, while those of the F-4, F-14, and
F-15 have variable geometry or variable ramp air inlets. This is a speed
limiting factor in the Hornet design. Instead, the Hornet uses bleed air vents
on the inboard surface of the engine air intake ducts to slow and reduce the
amount of air reaching the engine. While not as effective as variable geometry,
the bleed air technique functions well enough to achieve near Mach 2 speeds,
which is within the designed mission requirements.
A 1989 USMC study found that single seat fighters were well
suited to air to air combat missions while dual seat fighters were favored for
complex strike missions against heavy air and ground defenses in adverse
weather. The question being not so much as to whether a second pair of eyes
would be useful, but as to having the second crewman sit in the same fighter or
in a second fighter. Single-seat fighters that lacked wingmen were shown to be
especially vulnerable
A/B
The F/A-18A is the single-seat variant and the F/A-18B is
the two-seat variant. The space for the two-seat cockpit is provided by a
relocation of avionic equipment and a 6% reduction in internal fuel; two-seat
Hornets are otherwise fully combat-capable. The B model is used primarily for
training. In 1992, the original Hughes AN/APG-65 radar was replaced with the
Hughes (now Raytheon) AN/APG-73, a faster and more capable radar. A model
Hornets that have been upgraded to the AN/APG-73 are designated F/A-18A+.
C/D
The F/A-18C is the single-seat variant and the F/A-18D is
the two-seat variant. The D-model can be configured for training or as an
all-weather strike craft. The "missionized" D model's rear seat is
configured for a Marine Corps Naval Flight Officer who functions as a Weapons
and Sensors Officer to assist in operating the weapons systems. The F/A-18D is
primarily operated by the U.S. Marine Corps in the night attack and FAC(A)
(Forward Air Controller (Airborne)) roles. The F/A-18C and D models are the
result of a block upgrade in 1987 incorporating upgraded radar, avionics, and
the capacity to carry new missiles such as the AIM-120 AMRAAM air-to-air
missile and AGM-65 Maverick and AGM-84 Harpoon air-to-surface missiles. Other
upgrades include the Martin-Baker NACES (Navy Aircrew Common Ejection Seat),
and a self-protection jammer. A synthetic aperture ground mapping radar enables
the pilot to locate targets in poor visibility conditions. C and D models
delivered since 1989 also have improved night attack abilities, consisting of
the Hughes AN/AAR-50 thermal navigation pod, the Loral AN/AAS-38 NITE Hawk FLIR
(forward looking infrared array) targeting pod, night vision goggles, and two
full-color (formerly monochrome) multi-function display (MFDs) and a color
moving map.
In addition, 60 D-model Hornets are configured as the night
attack F/A-18D (RC) with ability for reconnaissance. These could be outfitted
with the ATARS electro-optical sensor package that includes a sensor pod and
equipment mounted in the place of the M61 cannon. Beginning in 1992, the
F404-GE-402 enhanced performance engine, providing approximately 10% more
maximum static thrust became the standard Hornet engine. Since 1993, the
AAS-38A NITE Hawk added a designator/ranger laser, allowing it to self-mark
targets. The later AAS-38B added the ability to strike targets designated by
lasers from other aircraft. Production of the F/A-18C ended in 1999. In 2000, the
last F/A-18D was delivered to the U.S. Marine Corps.
E/F Super Hornet
The single-seat F/A-18E and two-seat F/A-18F Super Hornets
carry over the name and design concept of the original F/A-18, but have been
extensively redesigned. The Super Hornet has a new, 25% larger airframe, larger
rectangular air intakes, more powerful GE F414 engines based on F/A-18's F404,
and upgraded avionics suite. Like the Marine Corps' F/A-18D, the Navy's F/A-18F
carries a Naval Flight Officer as a second crewman in a Weapons Systems Officer
(WSO) role. The Super Hornet aircraft is in production and has equipped 22
squadrons.
The EA-18G Growler is an electronic warfare version of the
two-seat F/A-18F, which entered production in 2007. The Growler will replace
the Navy's EA-6B Prowler and carries a Naval Flight Officer as a second crewman
in an Electronic Countermeasures Officer (ECMO) role. Australia is the only
nation other than the United States to operate the Super Hornet.
Other US variants
F-18(R)
This was a proposed reconnaissance version of the F/A-18A.
It included a sensor package that replaced the 20 mm cannon. The first of two
prototypes flew in August 1984. Small numbers were produced.
RF-18D
Proposed two-seat reconnaissance version for the US Marine
Corps in the mid-1980s. It was to carry a radar reconnaissance pod. The system
was canceled after it was unfunded in 1988. This ability was later realized on
the F/A-18D(RC).
TF-18A
Two-seat training version of the F/A-18A fighter, later
redesignated F/A-18B.
F-18 HARV
Single-seat High Alpha Research Vehicle for NASA. High
angles of attack using thrust vectoring, modifications to the flight controls,
and forebody strakes
X-53 Active Aeroelastic Wing
A NASA F/A-18 has been modified to demonstrate the Active
Aeroelastic Wing technology, and was designated X-53 in December 2006.
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