The McDonnell Douglas (now Boeing) AV-8B Harrier II, manufactured by BAE SYSTEMS and Boeing, is a single-engine ground-attack aircraft that constitutes the second generation of the Harrier Jump Jet family. Capable of vertical or short takeoff and landing (V/STOL), the aircraft was designed in the late 1970s as an Anglo-American development of the British Hawker Siddeley Harrier, the first operational V/STOL aircraft.
The AV-8B is used by the United States Marine Corps (USMC), the Spanish Navy, and the Italian Navy. A variant of the AV-8B, the British Aerospace Harrier II, was developed for the British military, while another, the TAV-8B, is a dedicated two-seat trainer.The AV-8B Harrier II extends the capabilities of the Harrier with the introduction of a multi-mode radar and beyond-visual-range missile capability.A variant of the AV-8B, the British Aerospace Harrier II, was developed for the British military, while another, the TAV-8B, is a dedicated two-seat trainer.
Breakdown of the Harrier Family Tree
The Harrier family line consists of four major versions composed of the Hawker Siddeley Harrier, the British Aerospace (BAe) Sea Harrier, the Boeing/BAe AV-8B Harrier II and the BAe Systems/Boeing Harrier II. Confusing at first, each model does differentiate form the other in some distinct way. The initial prodution model and beginning of the Harrier lineage was the Hawker Siddeley Harrier. The Sea Harrier (as the name implies) became the dedicated navalized version of the base Harrier and utilized for air-defence as a primary role and groung strike as secondary. The Sea Harrier also made use of the powerful Blue Fox radar and was a direct development of the land-based RAF Harrier GR3. The Boeing/BAe AV-8B Harrier II became a "second generation" Harrier and is a highly-modifed version of the original Harrier for use bt The USMC while the BAe Harrier II is a British-modified strike version of the USMC Harrier II.
Hawker Aircraft Limited was absorbed by Hawker Siddeley Group in the late 1950s and became British Aerospace (BAe) in 1977. British Aerospace became BAe System in 1999 after its purchase of Marconi Electronic System.
Development
Even before the Sea Harrier was in development,the British and Americans were entering an option for an Advanced Harrier concept. Bristol has developed and successfully tested the Pegasus 15 with its 24,500lbf output rating. This new engine was noticeably larger in diameter than the existing family of Pegasus turbofans driving the existing (and original) Hawker Siddeley Harrier. The thinking now was that a whole new airfrme could be designed around the Pegasus 15 to take on its potential capabilities. As such, a new join venture was begun in 1972.
AV-8 Harrier concluded in a 15-year agreement in which American-based McDonnell Douglas could lay claim to local production of the aircarft (this never took place) as well as take on any future derivative development. Seeing it that thr RAF was already looking ahead to the original Harrier's replacement (as were the USMC) and the US Navy was looking to replace their agung fleet of Douglas A-4 Skyhawk, the endeavor was a soun d one to unertake. The Advance Harrier project gained the unofficial designation of AV-16 while Hawker Siddeley assigned the desgnation of P.1184 to it.
In march of 1975, citing "insufficient commond ground" in the program and (perhaps the most likely culprit) ballooning cost in a shrinking English defence enviroment, Hwker Siddeley decided to remove themselves from the project altogether. The Pegasus engine was far from being cleared for operational use and further money and time would be needed to make that happen. Couple that with the work needed to design, develop and test a new airframe amongst the diminishing defence budget in Britain and the Hawker Siddeley move becomes understanable. Unable to go at it alone, the United States wqually abondoned the project and that was that. Hawker continued some work onfinding a "super Harrier" solution but these all came naught.
Despite the project's termination, the two companies continued to take different paths toward an enhanced Harrier. Hawker Siddeley focused on a new larger wing that could be retrofitted to existing operational aircraft, while McDonnell Douglas independently pursued a less ambitious, though still expensive, project catering to the needs of the US military. Using knowledge gleaned from the AV-16 effort, though dropping some items—such as the larger Pegasus engine—McDonnell Douglas kept the basic structure and engine for an aircraft tailored for the USMC.
As the USMC wanted a substantially improved Harrier without the development of a new engine, the plan for Harrier II development was authorized by the United States Department of Defense (DoD) in 1976. The United States Navy (USN), which had traditionally procured military aircraft for the USMC, insisted that the new design be verified with flight testing. McDonnell Douglas modified two AV-8As with new wings, revised intakes, redesigned exhaust nozzles, and other aerodynamic changes; the modified forward fuselage and cockpit found on all subsequent aircraft were not incorporated on these prototypes. Designated YAV-8B, the first converted aircraft flew on 9 November 1978, at the hands of Charles Plummer. The aircraft performed three vertical take-offs and hovered for seven minutes at Lambert–St. Louis International Airport. The second aircraft followed on 19 February 1979, but crashed that November due to engine flameout; the pilot ejected safely. Flight testing of these modified AV-8s continued into 1979. The results showed greater than expected drag, hampering the aircraft's maximum speed. Further refinements to the aerodynamic profile yielded little improvement. Positive test results in other areas, including payload, range, and V/STOL performance, led to the award of a development contract in 1979. The contract stipulated a procurement of 12 aircraft initially, followed by a further 324.
Between 1978 and 1980, the DoD and USN repeatedly attempted to terminate the AV-8B program. There had previously been conflict between the USMC and USN over budgetary issues. At the time, the USN wanted to procure A-18s for its ground attack force and, to cut costs, pressured the USMC to adopt the similarly-designed F-18 fighter instead of the AV-8B to fulfill the role of close air support (both designs were eventually amalgamated to create the multirole F/A-18 Hornet). Despite these bureaucratic obstacles, in 1981, the DoD included the Harrier II in its annual budget and five-year defense plan. The USN declined to participate in the procurement, citing the limited range and payload compared with conventional aircraft.
In August 1981, the program received a boost when British Aerospace (BAe) and McDonnell Douglas signed a Memorandum of Understanding (MoU), marking the UK's re-entry into the program. The British government was enticed by the lower cost of acquiring Harriers promised by a large production run, and the fact that the US was shouldering the expense of development. Under the agreement BAe was relegated to the position of a subcontractor, instead of the full partner status that would have been the case had the UK not left the program. Consequently, the company received, in man-hours, 40 percent of the airframe work-share. Aircraft production took place at McDonnell Douglas' facilities in suburban St. Louis, Missouri, and manufacturing by BAe at its Kingston and Dunsfold facilities in Surrey, England. Meanwhile, 75 percent work-share for the engine went to Rolls-Royce, which had previously absorbed Bristol Siddeley, with the remaining 25 percent assigned to Pratt & Whitney. The two companies planned to manufacture 400 Harrier IIs, with the USMC expected to procure 336 aircraft and the RAF, 60.
Four full-scale development (FSD) aircraft were constructed. The first of these (BuNo 161396), used mainly for testing performance and handling qualities, made its maiden flight on 5 November 1981, piloted by Plummer. The second and third FSD aircraft, which introduced wing leading-edge root extensions and revised engine intakes, first flew in April the following year; the fourth followed in January 1984.
Design
Harrier II Plus cockpit
The cockpit is fully integrated for day and night operability and is equipped with head-up and head-down displays, a digital moving map, an inertial navigation system (INS) and a hands-on throttle and stick system (HOTAS).
Airframe
For the AV-8B, McDonnell Douglas redesigned the entire airframe of the Harrier, incorporating numerous structural and aerodynamic changes. To improve visibility and better accommodate the crew and avionics hardware, McDonnell Douglas elevated the cockpit by 10.5 in (27 cm) and redesigned the canopy. This improved the forward (17° down), side (60°), and rear visibility. The front fuselage is composed of a molded skin with an epoxy-based core sandwiched between two carbon-fiber sheets. To compensate for the changes in the front fuselage, the rear fuselage was extended by 18 in (46 cm), and the taller vertical stabilizer of the Sea Harrier was used. The tail assembly is made up of composites to reduce weight.
Perhaps the most thorough redesign was of the wing, the objective being to match the performance of the cancelled AV-16 while retaining the Pegasus engine of the AV-8A. Engineers designed a new, one-piece supercritical wing, which improves cruise performance by delaying the rise in drag and increasing lift-to-drag ratio. Made of composites, the wing is thicker and has a longer span than that of the AV-8A. Compared to the AV-8A's wing, it has a higher aspect ratio, reduced sweep (from 40° to 37°), and an area increased from 200 sq ft (18.6 m2) to 230 sq ft (21.4 m2). The wing has a high-lift configuration, employing flaps that deploy automatically when maneuvering, and drooped ailerons. Using the leading edge root extensions, the new wing allows for a 6,700 lb (3,035 kg) increase in payload compared with the first-generation Harriers after a 1,000 ft (300 m) takeoff roll. Because the wing is almost exclusively composite, it is 330 lb (150 kg) lighter than the AV-8A's smaller wing.
The Harrier II was the first combat aircraft to extensively employ carbon-fiber composite materials, exploiting their light weight and high strength; they are used in the wings, rudder, flaps, nose, forward fuselage, and tail. Twenty-six percent of the aircraft's structure is made of composites, reducing its weight by 480 lb (217 kg) compared to a conventional metal structure.
Harrier weapons
The Harrier II Plus is capable of deploying a wide range of weapon systems, including the air-to-air AMRAAM and Sparrow missiles, air-to-surface AGM-65 Maverick missiles, anti-ship Harpoon and Sea Eagle missiles, a 25mm cannon, and a range of bombs and rockets.
The AIM-120A Advanced Medium-Range Air-to-Air Missile (AMRAAM) from Raytheon Missile Systems is an all-weather, fire-and-forget, air-to-air missile, equipped with an active radar seeker and a high-explosive warhead. The range is over 50 miles, and the speed of the missile is 1.2km a second.
The Maverick AGM-65 anti-tank missile is installed on the Italian Harrier II Plus. The AIM-7 Sparrow medium-range, air-to-air missile, a predecessor to the Raytheon AIM-120 AMRAAM, is held in the arms inventories of many countries, including the user countries of the Harrier II Plus aircraft. The Harrier II Plus is capable of deploying the Sea Eagle anti-ship missile from MBDA (formerly Matra BAe Dynamics), which is a fire-and-forget, sea-skimming missile also carried on the Sea Harrier, and the air-launch version of Harpoon AGM-84 surface strike missile from Boeing.
USMC Harriers are fitted with the 1,000lb Joint Direct Attack Munition (JDAM).
AV-8B aircraft have been fitted with the Northrop Grumman Litening II targeting and reconnaissance pod. Litening II consists of a CCD TV camera for video reconnaissance and FLIR and laser spot tracker or rangefinder for targeting.
These are to be replaced with the latest generation Litening Advanced Targeting pod.
Sensors
The Harrier II Plus is equipped with the Raytheon APG-65 digital radar to provide day and night and adverse weather capability. The APG-65 is a jam-resistant, all-weather detection and tracking radar. In the air-to-air role, the radar operates in search, track and combat modes. Long-range interception missions use the radar's long-range detection capability and, for the close-in air defense role, the radar uses rapid acquisition modes for the aircraft's 25mm cannon and heat-seeking missiles.
In the air-to-surface role, the APG-65 radar provides high-resolution, long-range surface mapping and detection, and tracking of land-based and sea-based targets. The radar has the capability to locate small, fast patrol boats in high sea states and to detect large naval ships at long range.
Avionics
The avionics suite of the Harrier II Plus is similar to that of the US Marine Corps' Night Attack AV-8B. It is equipped with a forward-looking infrared (FLIR) sensor, night-vision goggles (NVG) and an NVG-compatible cockpit.
The image from the FLIR is projected on the wide-field-of-view, head-up display or on one of the multipurpose, head-down displays to provide night-time and reduced-visibility capability.
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| Rolls-Royce Bristol Pegasus, engine of the vertical takeoff Harrier, in the Bristol Industrial Museum, England. |
The Pegasus engine 11-61 (F402-RR-408) from Rolls-Royce provides a high thrust-to-weight ratio and retains its performance in hot and high-altitude conditions.
The significant aerodynamic features of the aircraft are large Leading-Edge Root Extensions (LERX) and under-fuselage Lift-Improvement Devices (LIDs), drooping ailerons (for example, the control surface that forms part of the trailing edge of the wing), and the slotted flaps augmented vectored engine thrust.
Performance
The Harrier II Plus can climb at a rate of 14,700ft per minute. Its maximum speed is 1,083km per hour. The normal and ferry ranges of the aircraft are 2,574km and 3,300km, respectively.
The aircraft's combat radius is 556km. It weighs around 6,743kg and its maximum take-off weight is 14,514kg.
Variant
AV-8A
Original US Harrier based on the British GR.1 (see Harrier & Sea Harrier)
YAV-8B
Prototype with a composite wing, redesigned engine intakes and exhaust nozzles, and improved lift devices rebuilt from AV-8A Harrier airframes to test features of a proposed AV-8B, successful demonstration resulted in a development contract in 1979; 2 converted
AV-8B Harrier II
Production day attack fighter for the US Marine Corps; 4 development versions and 162 production airframes built from 1982-1989
TAV-8B Harrier II
Two-seat trainer for the USMC; 23 built from 1986-1992
GR.5
UK version of the Harrier II with different avionics, countermeasures, and weapon options than the US model; 41 built for the Royal Air Force
GR.5A
Slightly modified GR.5 model incorporating design changes in anticipation of the GR.7 standard; 21 built for the Royal Air Force
EAV-8B Matador II
Carrier-based attack model similar to the AV-8B built for the Spanish Navy; 12 built from 1987-1988
AV-8B Harrier II Night Attack
Upgraded US Marine Corps model adding a Navigation Forward Looking Infrared (NAVFLIR) camera, upgraded cockpit, compatibility with night vision goggles, and an updated engine; many converted from original AV-8B airframes and 72 new airframes built from 1989-1993
AV-8D
Early designation for the AV-8B Harrier II Night Attack variant
GR.7
UK variant optimized for night attack and equipped with new cockpit displays and a HUD, TV/laser target trackers, and a FLIR, saw combat in Kosovo and Iraq and began deployments aboard aircraft carriers in 1997; 34 built and all GR.5 airframes upgraded to this standard
T.6
Proposed two-seat trainer for the RAF based on the Harrier T.4 but incorporating GR.7 avionics; cancelled in 1990 in favor of a true Harrier II trainer called the T.10
T.10
RAF trainer based on the American TAV-8B except incorporating night attack and full combat capability; 13 built
GR.7A
Upgrade to GR.7 airframes adding a more powerful engine
AV-8B Harrier II+
Similar to the AV-8B Harrier II Night Attack model except also incorporating an APG-65 radar; 72 converted and 43 built from 1993-1997 for use by the USMC and Italy
TAV-8B Harrier II+
Two-seat trainer purchased by the Italian Navy; 2 built from 1990-1991
EAV-8B Matador II+ Spanish version of the Harrier II+; 11 converted from EAV-8B airframes and 8 new airframes built from 1995-1997
GR.9
GR.7 airframes upgraded with new inertial navigation and GPS systems plus the ability to carry smart weapons such as Maverick, Brimstone, and Enhanced Paveway laser-guided/GPS-guided bombs for improved ground attack in all-weather conditions
GR.9A
GR.7A airframes upgraded with the avionics and weapon options of the GR.9
T.12
T.10 trainers updated with the avionics and weapon upgrades of the GR.7 and GR.9 models
Specifications (AV-8B Harrier II Plus)
Data from Nordeen, Boeing, and Airforce-technology.com
General characteristics
Crew: 1 pilot
Length: 46 ft 4 in (14.12 m)
Wingspan: 30 ft 4 in (9.25 m)
Height: 11 ft 8 in (3.55 m)
Wing area: 243.4 sq ft (22.61 m²)
Airfoil: supercritical airfoil
Empty weight: 13,968 lb (6,340 kg)
Loaded weight: 22,950 lb (10,410 kg)
Max. takeoff weight:
Rolling: 31,000 lb (14,100 kg)
Vertical: 20,755 lb (9,415 kg)
Powerplant: 1 × Rolls-Royce F402-RR-408 (Mk 107) vectored-thrust turbofan, 23,500 lbf (105 kN)
Performance
Maximum speed: Mach 0.9 (585 knots, 673 mph, 1,083 km/h)
Range: 1,200 nmi (1,400 mi, 2,200 km)
Combat radius: 300 nmi (350 mi, 556 km)
Ferry range: 1,800 nmi (2,100 mi, 3,300 km)
Rate of climb: 14,700 ft/min (4,481 m/min)
Wing loading: 94.29 lb/(sq ft) (460.4 kg/m²)
Armament
Guns: 1× General Dynamics GAU-12 Equalizer 25 mm (0.984 in) 5-barreled Gatling cannon mounted under-fuselage in the left pod, with 300 rounds of ammunition in the right pod
Hardpoints: 6× under-wing pylon stations holding up to 9,200 lb (4,200 kg) of payload:
Rockets:
4× LAU-5003 rocket pods (each with 19× CRV7 70 mm rockets)
Missiles:
Air-to-air missiles:
4× AIM-9 Sidewinder or similar-sized infrared-guided missiles
6× AIM-120 AMRAAM (on radar equipped AV-8B Plus variants)
Air-to-surface missiles:
6× AGM-65 Maverick; or
2× AGM-84 Harpoon; or
2× AGM-88 HARM
Bombs:
CBU-100 cluster bombs (CBUs)
Mark 80 series of unguided bombs (including 3 kg [6.6 lb] and 14 kg [31 lb] practice bombs)
Paveway series of laser-guided bombs (LGBs)
Joint Direct Attack Munitions (GBU-38, GBU-32, and GBU-54)
Mark 77 napalm canisters
B61 nuclear bomb
Others:
up to 4× 300/330/370 US Gallon drop tanks (pylon stations No. 2, 3, 4, & 5 are wet plumbed)
Intrepid Tiger II electronic jammer
Avionics
Raytheon APG-65 radar
AN/AAQ-28V LITENING targeting pod (on radar-equipped AV-8B Plus variants)