Development of a much more powerful successor to the Harrier began in 1973 as a cooperative effort between McDonnell Douglas (MDD) in the US and Hawker Siddeley (in 1977, its aviation interests were nationalised to form part of British Aerospace in the UK. First-generation Harriers were being introduced into Royal Air Force and United States Marine Corps operational experience had highlighted demand for a more capable aircraft. The British government had only a minor requirement, for up to 60 Harriers at most and competing pressures on the defence budget left little room for frivolous expenditure such as the Advanced Harrier. A lack of government backing for developing the necessary engine of the new aircraft, the Pegasus 15, led Hawker to withdraw from this project in 1975.
Due to US interest, work proceeded on the development of a less ambitious successor, a Harrier fitted with a larger wing and making use of composite materials in its construction. Two prototypes were built from existing aircraft and flew in 1978. The US government was content to continue if a major foreign buyer was found and Britain had a plan to improve the Harrier with a new, larger metal wing. In 1980, the UK considered if the American program would meet their requirements – their opinion was that it required modification, thus the MDD wing design was altered to incorporate the British-designed leading-edge root extensions In 1982, the UK opted to become fully involved in the joint US–UK programme.The US and UK agreement to proceed included a British contribution of US$280 million to cover development costs to meet their own requirements and to purchase at least 60 aircraft.
The UK agreement included the involvement of British Aerospace (BAe) as a major subcontractor, manufacturing sections such as the rear fuselage for all customers of the AV-8B. The Harrier II was an Anglicised version of the AV-8B, British Aerospace producing the aircraft as the prime contractor, with McDonnell Douglas serving as a sub-contractor; final assembly work was performed at Dunsfold England The first prototype flew in 1981, first BAe-built development GR5 flew for the first time on 30 April 1985 and the aircraft entered service in July 1987. The GR5 had many differences from the USMC AV-8B Harriers, such as avionics fit, armaments and equipment; the wing of the GR5 featured a stainless steel leading edge, giving it different flex characteristics from the AV-8B.In December 1989, the first RAF squadron to be equipped with the Harrier II was declared operational.
The Harrier II is an extensively modified version of the first generation Harrier GR1/GR3 series. The original aluminium alloy fuselage was replaced with one made extensively of composites, providing significant weight reduction and increased payload or range. A new one-piece wing provides around 14 per cent more area and increased thickness. The wing and leading-edge root extensions allows for a 6,700-pound (3,035 kg) payload increase over a 1,000 ft (300 m) takeoff compared with the first generation Harriers.The RAF’s Harrier IIs feature an additional missile pylon in front of each wing landing gear, as well as strengthened leading edges on the wings in order to meet higher bird strike requirements.Among the major differences with the American cousin, was the new ZEUS ECM system, also proposed for the USMC AV-8 (which retained, after an evaluation, the original ALQ-164). ZEUS was one of the main systems in the British design, being a modern and costly apparatus, with an estimated cost of $1.7 million per set.
The Harrier II’s cockpit has day and night operability and is equipped with a head-up display (HUD), two head-down displays known as multi-purpose colour displays (MPCD), a digital moving map, an inertial navigation system (INS), and a hands-on-throttle-and-stick system Like the British Aerospace Sea Harrier, the Harrier II used an elevated bubble canopy to provide a significantly improved all-round view. A combination of the new design of the control system and the greater lateral stability of the aircraft made the Harrier II fundamentally easier to fly than the first generation Harrier GR1/GR3 models.
The RAF used Harriers in the ground attack and reconnaissance roles, so they relied on the short-range AIM-9 Sidewinder missile for air combat. The Sidewinder had proven effective for Royal Navy’s Sea Harriers against Argentinian Mirages in the Falklands War however, from 1993 the Sea Harrier FA2 could also carry the much longer-range AIM-120 AMRAAM, a radar-guided missile. The Sea Harrier had a radar since its introduction and the USMC later equipped their AV-8B Harriers with a radar as part of the AV-8B+ upgrade; however Britain’s Harrier IIs never carried a radar. When the Sea Harrier was retired, it was suggested that its Blue Vixen radar could be transferred to the Harrier IIs. However, the Ministry of Defence rejected this as risky and too expensive; the Armed Forces Minister Adam Ingram estimated that the cost would be in excess of £600 million.
further developments.
Even prior to the Harrier GR5 entering service, it was clear that alterations were required for the aircraft to be more capable in the interdictor role. A more advanced model, designated as the Harrier GR7, was developed primarily to add a night-time operational capability and avionics improvements. The GR7 development programme operated in conjunction with a similar USMC initiative upon its AV-8B Harrier fleet. Additional avionics include a nose-mounted forward-looking infrared (FLIR) and night vision goggles, a missile approach warning system (MAW) an electronic countermeasures suite, new cockpit displays and a replacement moving map system. The GR7 conducted its maiden flight in May 1990 and entered service in August 1990. Following the full delivery of 34 Harrier GR7s in 1991, all of the GR5s underwent avionics upgrades to become GR7s as well.
RAF Harrier II flying above RAF , Cyprus, 2010
Some GR7s were equipped with uprated Rolls-Royce Pegasus engines, correspondingly redesignated as GR7A; these Harriers had significantly improved takeoff and landing capabilities, and could carry greater payloads. In order to guide laser-guided bombs, from 1998 onwards a number of TIALD laser designator pods were made available to the Harrier II fleet, however these proved to be extremely scarce and often unavailable for pilot training. In response to difficulties experienced while communicating with aircraft during the 1999 Kosovo War, the GR7s were upgraded with encrypted communications equipment.
A further major upgrade programme from the GR7 standard was conducted; the Harrier GR9. The GR9 was developed via the Joint Update and Maintenance Programme (JUMP), which significantly upgraded the Harrier fleet’s avionics, communications systems, and weapons capabilities during scheduled periods of maintenance in an incremental manner. The upgrade also replaced the composite rear fuselage of the GR7 with one made of metal which was less vulnerable to damage from engine vibrations. The first of the incremental improvements started with software upgrades to the communications, ground proximity warning and navigation systems, followed by the integration of the AGM-65 Maverick air-to-ground missile. Capability C added the RAF’s Rangeless Airborne Instrumentation Debriefing System (RAIDS), Raytheon’s Successor Identification Friend or Foe (SIFF) system and the Paveway guided bombs. The Digital Joint Reconnaissance Pod (DJRP) was added as part of Capability D.
In February 2007, handling trials of the MBDA [Brimstone (missile) however the Brimstone would remain uncleared for deployment on the GR9 by the type’s early retirement. The targeting pod replaced the less accurate TIALD in 2007, under an Urgent Operational Requirement (UOR) for Afghanistan. Capability E would have included a communications link, an auxiliary communications system, and a Tactical Information Exchange Capability (TIEC) system that was planned to by deployed on both the Harrier II and the Tornado GR4. In July 2007, BAE Systems completed the final of seven Harrier GR9 replacement rear fuselages for the MoD. The fuselage components were designed and built as part of a three-year £20 million programme. In July 2008, Qinetiq was awarded a contract to perform upgrades and maintain the Harrier II fleet until 2018, which was the predicted out of service date for the type.
the GR.7
The GR7 is an upgraded model of the GR5. The first GR7 conducted its maiden flight in May 1990, and made its first operational deployment in August 1995 over the former Yugoslavia.
GR.7A
The GR7A feature an uprated Pegasus 107 engine GR7As upgraded to GR9 standard retain the A designation as GR9As. The Mk 107 engine provides around 3,000 lbf (13 kN) extra thrust the Mk 105’s 21,750 lbf (98 kN) thrust.