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The McDonnell Douglas (now Boeing) F/A-18 Hornet is an all-weather carrier-capable multirole fighter jet, designed to attack both ground and aerial targets. The F/A-18 was derived from the 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 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 F-14 Tomcat in the fighter and strike fighter role, and the A-6 Intruder and A-7 Corsair II in the attack role.
F/A-18 Hornet provided the baseline design for the 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 capability. The F/A-18E/F was originally proposed as an alternative to a completely 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.
The F/A-18 is a twin engine, mid-wing, multi-mission tactical aircraft. It is superbly 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. This is because the LEX produce powerful vortices over the wings, creating turbulent airflow over the wings and thus delaying or eliminating the aerodynamic separation responsible for stall, allowing the Hornet's wings to generate lift several times the aircraft's weight, despite high angles of attack. The Hornet is therefore capable of extremely tight turns over a large range of speeds.
Canted vertical stabilizers are another distinguishing design element, and among the other design characteristics that enable the Hornet's excellent high angle-of-attack capability 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 utilize multi-function displays, which at the switch of a button allow the pilot to perform either fighter or attack roles or both. This "force multiplier" capability gives the operational commander more flexibility in employing tactical aircraft in a rapidly 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 with maintenance in mind, 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. For example, whereas replacing the engine on the A-4 Skyhawk required removing the aircraft's tail, the engine on the Hornet is attached at only three points and can be directly removed without excessive disassembly. An experienced maintenance crew can remove and replace an F/A-18 engine in only a couple of hours.
The General Electric F404-GE-400 or F404-GE-402 engines powering the Hornet were also innovative in that they were designed with operability, reliability, and maintainability first. The result is an engine that, while unexceptional on paper in terms of rated performance, demonstrates exceptional robustness under a variety of conditions and is resistant to stall and flameout. By contrast, the Pratt & Whitney TF30 engines that originally powered the F-14A were notoriously prone to compressor stall and flameout under certain flight conditions.
The engine air inlets of the Hornet, like that of the F-16, are "fixed", while those of the F-4, F-14, and F-15 have variable geometry or variable ramp engine air inlets. The variable geometry enables high-speed aircraft to keep the velocity of the air reaching the engine below supersonic. This is one 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. The less sophisticated design is also more robust.
Because it was designed as a light multirole aircraft to complement the specialized F-14 and A-6 airframes, it had a relatively low internal fuel fraction. That is, its internal fuel capacity is small relative to its takeoff weight, at around 23%, a fuel fraction of .23. Most aircraft of its class have a fuel fraction between .30 to .35. This situation was exacerbated by the addition of new avionics over its lifespan, further reducing the fuel fraction. This led to 330-gallon external tanks being a common sight on F/A-18s, with the centerline and inner wings stations (numbered 3, 5 and 7) being plumbed to transfer fuel.
In the 1990s, the US Navy faced the need to replace its aging A-6 Intruders, EA-6 Prowlers, A-7 Corsair IIs and F-14 Tomcats without proper replacements in development. To answer this deficiency, the Navy had the F/A-18E/F Super Hornet developed. Despite its designation, it is not an upgrade of the F/A-18 Hornet, but rather, a new, larger airframe utilizing the design concepts of the Hornet. Hornets and Super Hornets will serve complementary roles in the US Navy carrier arsenal, until the deployment of the F-35C Lightning II, which will primarily replace F/A-18A-D Hornets.
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