Authored By Dan Alex (Updated: 7/2/2014):
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 from the other in some distinct way. The initial production 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-defense as a primary role and ground 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 GR.3. The Boeing/BAe AV-8B Harrier II became a "second generation" Harrier and is a highly-modified version of the original Harrier for use by 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 Systems in 1999 after its purchase of Marconi Electronic Systems.
This article covers the second generation McDonnell Douglas Corporation (MDC) / BAe Systems AV-8B and Harrier GR types. Other models are reviewed elsewhere on this site under their respective manufacturers.
Even before the Sea Harrier was in development, the British and Americans were entertaining 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 airframe could be designed around the Pegasus 15 to take on its potential capabilities. As such, a new joint venture was begun in 1972.
An original agreement between the British and American governments made for acquisition of foreign-made AV-8 Harriers concluded in a 15-year agreement in which American-based McDonnell Douglas could lay claim to local production of the aircraft (this never took place) as well as take on any future derivative development. Seeing it that the RAF was already looking ahead to the original Harrier's replacement (as were the USMC) and the US Navy was looking to replace their aging fleet of Douglas A-4 Skyhawks, the endeavor was a sound one to undertake. The Advanced Harrier project gained the unofficial designation of AV-16 while Hawker Siddeley assigned the designation of P.1184 to it.
The P.1184 would be a highly-modified version of the original Harrier design. To go along with the new Pegasus 15 series engine was a new wider fuselage. More importantly, a new "supercritical" wing, The wing was categorized as such in that it featured a specially-designed airfoil that worked to delay the onset of wave drag while at transonic speeds. Like the Harrier before it, the AV-16 would also be of a subsonic aircraft design. The wing would also increase external weapons carrying capacity to six underwing hardpoints while also be able to store more internal fuel thusly increasing range. A second study, becoming the AV-16-S6/P.1185, was developed as a high-altitude supersonic derivative.
Externally, the AV-16-S6 would appear as a much streamlined and longer version of the Sea Harrier complete with bubble canopy and single vertical tail fin. The wider fuselage would fit two large side intakes feeding the new Pegasus 15 engine. The outboard riggers would be set behind the innermost underwing hardpoint but the general Harrier layout would be retained.
In March of 1975, citing "insufficient common ground" in the program and (perhaps the most likely culprit) ballooning costs in a shrinking English defense environment, Hawker 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 defense budget in Britain and the Hawker Siddeley move becomes understandable. Unable to go at it alone, the United States equally abandoned the project and that was that. Hawker continued some work on finding a "super Harrier" solution but these all came to naught.
McDonnell Douglas, too, worked along with their own Harrier research and came to the conclusion that new, carbon fiber supercritical wing with larger surface area was the answer. Though larger than any other carbon fiber wing of the time, the new assembly would actually weigh less than the original all-metal wing. The original Harrier design was furthered by implementing larger air intakes, slotted flaps, additional air-lift devices and a retractable lateral fence to assist in capturing a cushion of air beneath the aircraft while in hover. The wings had their sweep revised by 4-degrees and were extended to promote better lateral control and cruising. Rolling was improved (as was lateral control by having the underwing-mounted thrusters set further apart. The wider wingspan also promoted the use of an additional underwing hardpoint and greater payloads. The outrigger landing legs were also brought in to provide for a more stable track during ground operation. The forward fuselage was inevitably revised with more composite construction and fitted with a higher cockpit and better canopy bubble canopy while the rear fuselage was lengthened. The vector thrust nozzles were lengthened.
The new changes in the Harrier line brought about by the Americans were now approved for development by the US government on July 27th, 1976. The aircraft would take on the designation of AV-8B and the first such developmental model incorporating the new changes was a modified non-flying AV-8A. Two flyable AV-8As were later converted (though without the fuselage changes) and garnered the development designation of YAB-8B and flown in 1979. Though proving slower than the original Harrier, the design was nonetheless a promising first step and completely fit into the needs for the USMC at the time. 1979 also saw US commitment to the "Harrier II" project in full with the first production order for 336 aircraft placed in the queue with McDonnell Douglas.
By now, the British had come to their senses and BAe was back in talks with McDonnell Douglas. As a benefit, the Americans did end up spending their own money in the development of the Harrier II and all the British would have to do is spend money on acquisition instead of research, development, testing AND manufacture. The major drawback to their situation lay in Harrier II's "as is" state which did not allow for much in the way of major modifications to suit British combat needs.
While the original Harrier's development/production saw the British take a majority role in the program while the Americans were given a minor stake in the project, roles were reversed with the production of the Harrier II. McDonnell Douglas would be responsible for up to 60% of the airframe construction while BAe would retain only 40%. Additionally, however, all American AV-8Bs would have final assembly handled at the McDonnell Douglas plant in St Louis, Missouri while all British aircraft would be have their final assembly handled at British Aerospace facility in Dunsford. Engine manufacturing would also be undertaken by a joint venture between Pratt & Whitney in America and Rolls-Royce in Britain.
The first pre-production Harrier II became airborne on November 5th, 1981. Three more such Harrier IIs followed with the final one fitting a common 25mm General Electric GAU-12/U multi-barrel Gatling-type cannon for weapons trials. The original Harrier fitted a pair of 30mm ADEN cannons in underfuselage pod fairings but these proved too unique for the American inventory as no other American aircraft fitted the weapon type. While not making use of the ADEN cannon set up, McDonnell Douglas kept the pod fairings for their aerodynamic value and instead used the portside pod fairing for the 25mm cannon and the starboard side pod fairing for 300 rounds of 25mm ammunition. The second YAV-8B prototype went airborne on February 19th, 1979, and initially proved successful but was eventually lost to an engine flame-out incident on November 15th of that year - the pilot ejecting safely.
The cockpit was wholly revised as a larger workspace with ergonomics an important consideration. The entire cockpit position was raised 12 full inches higher than previous and the two-piece canopy was given a higher apex for more headroom and better vision out of the cockpit. The navigation and avionics suites were both addressed with more powerful and capable systems although these systems would differ between the American and British aircraft as expected. HOTAS (Hands-On Throttle and Stick) was integrated as was a more effective HUD (Heads-Up Display). Large Multi-Function Displays (MFDs) as found on the F/A-18 Hornet were utilized in the new American development while the bombing system of the Douglas A-4 Skyhawk was implemented.
The ALR-67 radar warning receiver was added as were two ALE-29 chaff/flare dispensers were affixed to the underside of the fuselage just aft of the speedbrake. Two ALE-39 dispensers were also fitted to the upper sides of the rear fuselage, greatly increasing the Harrier IIs survivability. Additionally, the centerline hardpoint could now field the ALQ-164(V) countermeasures pod. Later, the AAR-44(V) was fitted to the tail stinger to warn of incoming enemy missiles from the rear.
The first dozen AV-8Bs were fitted with the F402-RR-404A turbofan engine while a newer F402-RR-406A (similar to the Pegasus Mk 105) series became the eventual mainstay of the Harrier II line. The Mark 105 engine had its roots in a Rolls-Royce venture taking place in 1980 and first test-flown on a Harrier GR.Mk 3 airframe beginning in 1982. Despite the use of the same powerplant in the new Harrier, the aircraft could still yield a greater payload and marked an impressive 70% improvement to hauling capabilities. Internal fuel stores were addressed and improved range by 50%. Along with these benefits came about a 60% reduction in maintenance hours required to keep the bird aloft.
The first AV-8B was flown on August 29th, 1983 and officially handed over to Training Squadron VMAT-203 at Cherry Point, North Carolina on January 12th, 1984. The first operational squadron became VMA-331 with numbers finally reaching 20 aircraft in March of 1987. The new systems proved more than the original AV-8A pilots could handle so a production order of eight AV-8Bs was cut in favor of developing the all-important two-seat TAV-8B Harrier II. The TAV-8B arrived in Marine hands on July 24th, 1987.
Differences between the production AV-8B and the TAV-8B were subtle. The TAV-8B naturally needed a larger cockpit to seat two pilots and was therefore afforded a lengthened fuselage. This was offset by a longer tail stinger and a taller vertical tail fin. Unlike the British trainers to come, the TAV-8B did not retain any of her combat capabilities and was a true trainer at heart fitting only a pair of underwing hardpoints for fuel and practice ordnance.
The second operational USMC squadron became the VMA-231 in July of 1986, with operating strength reached at 15 AV-8Bs. Before the end of 1986, squadron VMA-457 was next brought online. These two squadrons were then followed into service by the VMA-513, which was incidentally the last operator of the original first-generation AV-8A Harriers.
The British took the American-modified AV-8B Harrier II and initially produced a pair of GR.Mk 5s that were fitted the Pegasus Mk 105 engine as well as British-based avionics, radio, countermeasures and applicable weaponry. First flight was achieved on April 23rd, 1985 and the first GR.Mk 5 went operational in July of 1987.
When all was said and done, the Harrier had evolved into a much more special combat platform. No longer tied to the notion of basic close-support sorties as its only forte, the Harrier II sprouted combat capabilities that made it a premiere ground strike aircraft with unparalleled attack helicopter-like capabilities no other conventional aircraft could match. The new Harrier could also defend itself through the use of internal cannons or externally-mounted short-range air-to-air missiles when armed as such.
McDonnell Douglas Corporation was absorbed as a subsidiary of the Boeing Company while BAe became BAe Systems. Each respective corporation now manages the current and future line of AV-8B Harrier IIs and Harrier GRs in service.