McDonnell Douglas AV-8B Harrier II Fighter Jet
The McDonnell Douglas (now Boeing) AV-8B Harrier II is a second-generation vertical/short takeoff and landing (V/STOL) ground-attack aircraft. An Anglo-American development of the British Hawker Siddeley Harrier, the Harrier II is the final member of the Harrier family that started with the Hawker Siddeley P.1127 in the early 1960s. The AV-8B is primarily used for light attack or multi-role missions, and is typically operated from small aircraft carriers, large amphibious assault ships and simple forward operating bases. The British Aerospace Harrier II variant of the AV-8B was developed for the British military. The AV-8B is used by the United States Marine Corps (USMC), Spanish Navy and Italian Navy. The TAV-8B is a dedicated two-seat trainer version. The Harrier II and other models of the Harrier family have been called "Jump Jets".
The AV-8B Harrier II is a subsonic attack aircraft. It retains the basic layout of the Hawker Siddeley Harrier, with horizontal stabilizers and shoulder-mounted wings featuring prominent anhedral. The aircraft is powered by a single Rolls-Royce Pegasus turbofan engine; the Pegasus's two intakes and four synchronized vectorable nozzles are located close to the turbine; two nozzles are near the forward, cold end of the engine and two nozzles are near the rear, hot end of the engine. This arrangement contrasts with most fixed-wing aircraft, which have their engine nozzles at the rear. The Harrier II also has smaller valve-controlled nozzles in the nose, tail and wingtips to provide control at low airspeeds. The AV-8B is equipped with one centerline and six wing hardpoints (up from five in total on the Hawker Siddeley Harrier) for carrying weapons and external fuel tanks, along with two fuselage stations for a 25 mm GAU-12 cannon and ammunition pack. The British Aerospace Harrier II, a variant tailored to the RAF, uses different avionics, and has one additional missile pylon on each wing.
The aircraft incorporates numerous structural and aerodynamic changes. MDC engineers designed a new, longer one-piece supercritical wing, which improves cruise performance by delaying drag rise and increasing lift-to-drag ratio. Made of carbon-fiber composites, the wing is thicker, has a larger aspect ratio, reduced sweep, and an area increased to 230 square feet (21.40 m2). The lighter wing has a high-lift configuration, employing flaps that automatically deploy during aircraft maneuvers, and drooped ailerons. The wing, when used in concert with leading-edge root extension (LERX, which are extensions to the root of the wing's leading-edge), allows for a 6,700-pound (3,035 kg) increase in payload compared with the first-generation Harriers after a 1,000 ft (300 m) takeoff roll. The Harrier II was the first combat aircraft to employ composite materials extensively; they are used on the wings, rudder, flaps, nose, forward fuselage and empennage. In total, 26 percent of the aircraft's structure is made of composites, reducing the weight of the aircraft by 480 lb (217 kg) compared with a conventional metal structure. The Harrier II retains the tandem undercarriage layout of the first-generation Harriers, although the outriggers were moved from the wingtip to mid-span for a tighter turning radius when taxiing. The engine intakes are bigger, and have a revised inlet. Underneath the fuselage centerline McDonnell Douglas added lift-improvement devices, which capture the reflected engine exhaust, equivalent to 1,200 lb (544 kg) of lift.
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 technological advances incorporated into the Harrier II, compared with the original Harrier, significantly reduce the workload on the pilot. The supercritical wing, hands-on-throttle-and-stick (HOTAS) control principle, and deliberately engineered lateral stability make the aircraft fundamentally easier to fly. Ed Harper, general manager for the McDonnell Douglas Harrier II development program, summarized: "The AV-8B looks a lot like the original Harrier and it uses the same operating fundamentals. It just uses them a lot better". The cockpit was elevated to give the pilot an improved all-round view. A large cathode-ray tube multi-purpose display, taken from the F/A-18 Hornet, makes up much of the instrument panel. It has a wide range of functions, including radar warning information and weapon delivery checklist. The pilots sit on UPC/Stencel 10B zero-zero ejection seats, meaning that they are able to eject in a stationary aircraft at zero altitude.