Harrier Jump Jet

The Harrier, informally referred to as the Harrier Jump Jet, is a family of jet-powered attack aircraft capable of vertical/short takeoff and landing operations (V/STOL). Named after a bird of prey,[1] it was originally developed by British manufacturer Hawker Siddeley in the 1960s. The Harrier emerged as the only truly successful V/STOL design of the many attempted during that era. It was a subsonic aircraft, unlike most of its competitors. It was conceived to operate from improvised bases, such as car parks or forest clearings, without requiring large and vulnerable air bases. Later, the design was adapted for use from aircraft carriers.

Harrier Jump Jet
Spanish EAV-8B Harrier II+ "Cobra" (27448607244) (cropped).jpg
A Harrier II in hover with downward jet exhaust
Role V/STOL strike aircraft
National origin United Kingdom
Manufacturer Hawker Siddeley
British Aerospace / McDonnell Douglas
Boeing / BAE Systems
First flight 28 December 1967
Introduction 1969
Status In service
Primary users United States Marine Corps
Royal Air Force (retired)
Royal Navy (retired)
Indian Navy (retired)
Produced 1967–2003
Developed from Hawker P.1127
Variants Hawker Siddeley Harrier
British Aerospace Sea Harrier
McDonnell Douglas AV-8B Harrier II
British Aerospace Harrier II

There are two generations and four main variants of the Harrier family, developed by both UK and US manufacturers:

The Hawker Siddeley Harrier is the first generation-version and is also known as the AV-8A Harrier; it was used by multiple air forces, including the Royal Air Force (RAF) and the United States Marine Corps (USMC). The Sea Harrier is a naval strike/air defence fighter derived from the Hawker Siddeley Harrier; it was operated by both the Royal Navy and the Indian Navy. During the 1980s, a second generation Harrier emerged; manufactured in the United States as the AV-8B and in Britain as the British Aerospace Harrier II respectively. By the start of the 21st century, the majority of the first generation Harriers had been withdrawn, many operators having chosen to procure the second generation as a replacement. In the long term, several operators have announced their intention to supplement or replace their Harrier fleets with the STOVL variant of the F-35 Lightning II, designated as the F-35B.

DevelopmentEdit

BackgroundEdit

Throughout the 1950s, particularly in the years following the Korean War, a number of aircraft companies in both Europe and America separately decided to investigate the prospective capabilities and viability of vertical take-off and landing (VTOL) aircraft, which would eliminate the requirement for vulnerable runways by taking off and landing vertically as opposed to the conventional horizontal approach.[2] In addition to military applications, the prospect of applying such technology to commercial airliners was also viewed with considerable interest by the mid 1950s, thus the value of developing viable vertical take-off systems was judged to be substantial. However, during this era, few companies envisioned that a VTOL aircraft could also be compatible with the characteristics of high performance military aircraft.[2]

 
Underside view of the first prototype P.1127. The rotating jet nozzles were a key design element of its VTOL capability

During 1957, following an approach by the British aero engine manufacturer Bristol Engine Company, who were designing an innovative vectored thrust engine, British aviation conglomerate Hawker Aircraft developed their design for an aeroplane that could meet an existing NATO specification calling for a "Light Tactical Support Fighter".[2] Bristol's projected vectored thrust engine, which received the name Pegasus,[N 1] harnessed rotatable cold jets which were positioned on either side of the compressor along with a 'hot' jet which was directed via a conventional central tailpipe; this concept had originated from Michel Wibault, a French aviation consultant. Throughout much of the early development work, there was no financial support for the project from HM Treasury; however, support for the engine development portion of the effort was sourced via NATO's Mutual Weapon Development Program (MWDP).[3][2][4]

Senior project engineer Ralph Hooper at Hawker promptly set about establishing an initial layout for a theoretical aircraft to take advantage of the Pegasus engine, using data provided by Bristol.[2] During March 1959, the newly merged Hawker Siddeley decided to privately fund a pair of prototypes of the design, which had received the internal company designation of P.1127, to demonstrate the design's capabilities.[5] During the 1960s, the P.1127 attracted the attention of the RAF; this would eventually result in the development and issuing of Requirement ASR 384, which sought a V/STOL aircraft for ground attack operations.[6] During late 1965, the RAF placed an order for six pre-production P.1127 (RAF) aircraft.[7]

Requirements and emergenceEdit

 
Hawker Siddeley XV-6A Kestrel in later USAF markings

Around the same time as the RAF's interest in the concept, NATO proceeded to develop their own specification, NBMR-3, which called for a vertical takeoff and landing (VTOL) aircraft; specific requirements included the expectation for the performance of such an aircraft to be equivalent to the conventional McDonnell Douglas F-4 Phantom II fighter. Specifications called for a supersonic V/STOL strike fighter with a combat radius of 460 kilometres (250 nmi), a cruise speed of Mach 0.92, and a dash speed of Mach 1.5.[8] During the early 1960s, Hawker commenced work upon developing a supersonic version of the P.1127, designated the P.1150, culminating in the abortive Hawker P.1154. NBMR.3 also attracted ten other contenders, among which was P.1154's principal competitor, the Dassault Mirage IIIV. The P.1154 was ultimately selected to meet NBMR-3; however, this did not lead to orders being placed.[9]

On 6 December 1961, prior to the design being submitted to NATO, it was decided that the P.1154 would be developed with the requirements for use by both the Royal Air Force (RAF) and Royal Navy (RN).[10] Following the cancellation of the NBMR-3 requirement, HSA focused all its attention on the British joint requirement.[9] Accordingly, development of the type continued for some time; however, by October 1963, the Ministry of Aviation was concerned with the project's progress, and noted that the effort to combine a strike aircraft and a fighter in a single aircraft, and trying to fit that same airframe to both of the services, was "unsound".[11] On 2 February 1965, work on the P.1154 was cancelled by the new British government on grounds of cost at the point of prototype construction.[12]

Irrespective of work on the P.1154 programme, development had continued on the subsonic P.1127 evaluation aircraft.[7] A total of nine aircraft, known as the Hawker Siddeley Kestrel, was ordered and manufactured for testing.[13] During 1964, the first of these had commenced flight operations; the Kestrel was assessed by the multinational "Tri-partite Evaluation Squadron", which consisted of British, US and German pilots, to determine how VTOL aircraft could be operated; the evaluations were finalised in November 1965.[14] During 1966, following the cancellation of the P.1154, the RAF opted to proceed with ordering a modified derivative of the P.1127/Kestrel for service, which was designated the Harrier GR.1.[7][15]

First-generation HarriersEdit

Hawker Siddeley Harrier, in Spanish service
British Aerospace Sea Harrier, in Royal Navy service

The Hawker Siddeley Harrier GR.1/GR.3 and the AV-8A Harrier were the first generation of the Harrier series, the first operational close-support and reconnaissance attack aircraft with vertical/short takeoff and landing (V/STOL) capabilities. These were developed directly from the Hawker P.1127 prototype and the Kestrel evaluation aircraft. On 18 April 1969, the Harrier GR.1 officially entered service with the RAF when the Harrier Conversion Unit at RAF Wittering received its first aircraft.[16] The United States Marine Corps (USMC) also chose to procure the type, receiving 102 AV-8A and 8 TAV-8A Harriers between 1971 and 1976.[17]

The British Aerospace Sea Harrier is a naval V/STOL jet fighter, reconnaissance and attack aircraft; it was a navalised development of the Hawker Siddeley Harrier. The first version entered service with the Royal Navy's Fleet Air Arm in April 1980 as the Sea Harrier FRS.1, and was informally known as the Shar.[18] Sea Harriers played a high-profile role in the Falklands War of 1982, flying from the aircraft carriers HMS Invincible and HMS Hermes.[19][20] Wartime experiences led to the production of an improved model in the form of the upgraded Sea Harrier FA2; this version entered operational service on 2 April 1993.[21][22] The Sea Harrier was also procured by the Indian Navy, where the first Indian Sea Harriers entered squadron service during December 1983.[23]

Second-generation HarriersEdit

McDonnell Douglas AV-8B Harrier II, in United States Marine Corps service
British Aerospace Harrier II, in Royal Air Force service

As early as 1973, Hawker Siddeley and American aviation manufacturer McDonnell Douglas were jointly working on development of a more capable version of the Harrier. Early efforts concentrated on the development of an improved Pegasus engine, designated the Pegasus 15, which was being tested by Bristol Siddeley.[24] During 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.[24] The Harrier was extensively redeveloped by McDonnell Douglas, and later joined by BAe (now parts of Boeing and BAE Systems, respectively), leading to the family of second-generation V/STOL jet multi-role aircraft. The American designation for this was the AV-8B Harrier II.[25]

On 12 December 1983, the first production AV-8B was delivered to the USMC. The AV-8B is primarily used for attack or multi-role tasks, typically operated from small aircraft carriers.[26][27] The RAF also chose to procure the second generation of the British Aerospace-built (with McDonnell Douglas as subcontractor) Harrier II GR5/GR7/GR9, which entered service in the mid-1980s.[28] This model was also operated by several other NATO countries, including Spain and Italy. In December 1989, the first RAF squadron to be equipped with the Harrier II was declared operational.[29] The British Harrier II was used by the RAF and later by the Royal Navy up to 2010, at which point the Harrier II and the Joint Force Harrier operational unit was disbanded as a cost-saving measure.[30][31]

Between 1969 and 2003, 824 Harrier variants were delivered. While the manufacture of new Harriers concluded in 1997, the last remanufactured aircraft (Harrier II Plus configuration) was delivered in December 2003, ending the Harrier production line.[32]

OperationEdit

 
Rolls-Royce Pegasus engine on display, sections have been cut out to provide an internal view
 
Locations of the four nozzles at the sides of the Pegasus engine.

The Harrier Jump Jet, capable of taking off vertically, can only do so at less than its maximum loaded weight. In most cases, a short take off is needed to lift the required amount of fuel and weapons needed for a training sortie/mission, using forward speed to supplement the jet lift with aerodynamic lift. A short takeoff also uses less fuel than a vertical take off. On aircraft carriers, a ski-jump ramp is used at the bow of the carrier to help the aircraft become airborne. Landings are not usually done in a conventional manner because the range of speeds at which this is advisable is narrow due to the relatively vulnerable outrigger undercarriage. Operationally, a near-vertical landing with some forward speed is preferred, and this technique called Shipborne rolling vertical landing (SRVL). Rotating the vectored thrust nozzles to some angle other than rearwards during normal flight (to a maximum of 8-degree forward of vertical, i.e. 98 deg.) is called vectoring in forward flight, or "VIFFing". This is a dog-fighting tactic, allowing for more sudden braking and higher turn rates. Braking could cause a chasing aircraft to overshoot and present itself as a target for the Harrier, a technique formally developed by the USMC for the Harrier in the early 1970s.[33][34] This technique was much discussed in the Media before the Falklands War in 1982, but ultimately not used by British pilots in that conflict.[35] However, the ability to rotate the nozzles slightly forwards did allow the aircraft to fly slowly backwards in the hover, which was widely used in British and American airshows.[36]

The wind direction is critical during VTOL manoeuvres because unless it enters the intake from straight ahead it will push the nose sideways as it turns to enter the intake (known as intake momentum drag). If not corrected immediately the aircraft will roll out of control. The pilot has a wind vane in front of the windscreen to help him keep pointing into the wind.[37] The procedure for vertical takeoff involves facing the aircraft into the wind. The swivelling nozzles are pointed vertically downwards (thrust vector 90°) and the throttle is pushed to its maximum stop, at which point the aircraft leaves the ground. The throttle is adjusted until hovering is achieved at the desired altitude.[38] The short-takeoff procedure involves proceeding with a normal takeoff and then rotating the nozzles partially downwards (a thrust vector less than 90°) at a speed below the normal takeoff speed; usually this is done at about 65 knots (120 km/h). For a shorter takeoff run the thrust vector is greater for more jet lift.[39] The reaction control system uses thrusters at the aircraft extremeties, nose, tail and wingtips. Thrust from the engine can be temporarily syphoned to control the aircraft's pitch, roll and yaw before it is going fast enough for the elevators, rudder and ailerons to become effective.[40]

The Harrier has been described by pilots as "unforgiving" to fly.[41] The aircraft is capable of both forward flight (where it behaves like a fixed-wing aircraft above its stall speed), as well as VTOL (where the conventional lift and control surfaces are ineffective) and STOL. Accelerating and decelerating transitions between hovering and conventional flight required considerable skill and concentration on the part of the pilot, especially in crosswind conditions.[42] Pilots for the combined UK/US/Germany trials on the Kestrel were first given several hours helicopter tuition[N 2][43] Royal Air Force pilots destined for Harrier squadrons were usually selected from those with single-seat fast-jet experience. On two occasions the Royal Air Force explored whether experienced helicopter pilots, with their ability to hover and transition to forward flight, would be a better source for Harrier squadrons. In both cases the pilots were completely out of their depth with conventional flight, navigation, orientation and weapons delivery at the high speeds of a fast jet.[44] With the introduction of two-seat Harriers less experienced pilots were introduced. The United States Marine Corps also started with very experienced pilots, who were mostly test pilots.[45] In addition to normal flight controls, the Harrier has a lever for controlling the direction of the four vectoring nozzles. Pilots were impressed that to control the aircraft's vertical flight required only a single lever added in the cockpit.[39] For horizontal flight, the nozzles are directed rearwards by shifting the lever to the forward position; for short or vertical takeoffs and landings, the lever is pulled back to point the nozzles downward.[46][47]

ReplacementEdit

During 2010, it was announced that the RAF and RN would retire their remaining Harriers by 2011,[48] and in December 2010 the RAF's Harrier GR9s made their last operational flights.[49] In June 2011, the MoD denied press reports that the aircraft were to be sold to the US Marine Corps for spares to support their AV-8B fleet.[50][51] However, at the end of November 2011, the Defence Minister Peter Luff announced the sale of the final 72 Harriers to the US Marine Corps, with the aircraft to be used as sources of spare parts for the Marine Corps' airworthy fleet.[52]

As of June 2015, the STOVL variant of the F-35 Lightning II (formerly the Joint Strike Fighter), designated the F-35B, is intended to replace the AV-8B Harrier II in service with the US Marine Corps[53][54] while the RAF and Royal Navy are scheduled to introduce the F-35B in 2016 with their first F35 unit, 617 Squadron.[55][56][57]

Italian Navy AV-8Bs are also slated to be replaced by 15 (originally 22) F-35Bs, which will form the air wing of Cavour.[58]

During the first half of 2016, the Indian Navy retired the last of their remaining 11 Sea Harriers, which had been operating from INS Viraat (formerly HMS Hermes), in favour of the conventional Mikoyan MiG-29K.[59]

Starting in 2007, Spain was looking to replace its Harrier IIs–with the likely option being the F-35B.[60][61] The Spanish government, in May 2014 however, announced that it had decided to extend the aircraft's service life to beyond 2025 due to a lack of funds for a replacement aircraft.[62]

VariantsEdit

Hawker P.1127
(1960)
Kestrel FGA.1
(1964)
Harrier GR.1/1A/3/3A
(from 1966)
Harrier T.2/2A/4/4A/8/52/60
(from 1970)
AV-8A/C/S Harrier Mk.50/53/55/Matador
TAV-8A/S Harrier Mk.54/Matador
Sea Harrier FRS.1/FRS.51/F(A).2
(from 1978)
AV-8B Harrier II/EAV-8B Matador II/AV-8B Harrier II Night Attack/AV-8B Harrier II Plus
(from 1983)
TAV-8B Harrier II/ETAV-8B Matador II/
Harrier GR.5/5A/7/7A/9/9A
(from 1985)
Harrier T.10/12

OperatorsEdit

 
Operators of the Harrier (all variants)
 
A Spanish Navy AV-8S Matador aircraft
 
United States Marine Corps AV-8A of VMA-231 in 1980
  India
  Italy
  Spain
  Thailand
  United Kingdom
  United States

SpecificationsEdit

An unusual feature of the Harrier family of aircraft is their use of two types of flight control to provide pitch, roll and yaw control: conventional control surfaces for wingborne flight, and a system of reaction control valves directing jets of bleed air from the high-pressure compressor of the engine out through the extremities of the nose, tail, and at the wingtips during vectored thrust–borne flight and hover modes. The two systems are fully interlinked but air is not supplied to the reaction control valves during conventional wingborne flight.[65]

Kestrel FGA.1 Harrier GR3/AV-8A Sea Harrier FA2 Harrier GR9 AV-8B+ Harrier
Crew One (Two for trainer versions)
Length 42 ftin (13.0 m) 47 ft 2 in (14.4 m) 46 ft 6 in (14.2 m) 46 ft 4 in (14.1 m) 47 ft 8 in (14.5 m)
Wingspan 22 ft 11 in (6.98 m) 25 ft 3 in (7.70 m) 25 ft 3 in (7.70 m) 30 ft 4 in (9.25 m) 30 ft 4 in (9.25 m)
Height 10 ft 9 in (3.28 m) 11 ft 4 in (3.45 m) 12 ft 4 in (3.76 m) 11 ft 8 in (3.56 m) 11 ft 8 in (3.56 m)
Empty Weight 10,000 lb (4,540 kg) 12,200 lb (5,530 kg) 14,052 lb (6,370 kg) 12,500 lb (5,670 kg)? 13,968 lb (6,340 kg)
Maximum take-off weight
(short takeoff)
17,000 lb (7,710 kg) 26,000 lb (11,800 kg) 26,200 lb (11,900 kg) 31,000 lb (14,100 kg) 31,000 lb (14,100 kg)
Max speed 545 mph (877.1 km/h) 731 mph (1,176 km/h) 735 mph (1,183 km/h) 662 mph (1,065 km/h) 662 mph (1,065 km/h)
Combat radius 200 nmi (370 km) 300 nmi (556 km) 300 nmi (556 km)
Engine Pegasus 6 Pegasus 11 Mk 101 Pegasus 11 Mk 106 Pegasus 11 Mk 107 Pegasus 11 Mk 105
Thrust 15,000 lbf (66.7 kN) 21,800 lbf (97.0 kN) 21,800 lbf (97.0 kN) 24,750 lbf (110 kN) 23,500 lbf (105 kN)
Radar None None Blue Fox / Blue Vixen None AN/APG-65
Sources: Nordeen[66]

See alsoEdit

Related development

Aircraft of comparable role, configuration, and era

Related lists

ReferencesEdit

NotesEdit

  1. ^ The name "Pegasus" for the engine was in keeping with Bristol's tradition of naming engines after figures from classical mythology.
  2. ^ In preparation for flying the Kestrel, pilots of the Tripartite Evaluation Squadron were provided with several hours of helicopter piloting tuition, all of whom agreed on the effort being highly worthwhile preparation.[43]

CitationsEdit

  1. ^ Searle, Adrian (29 June 2010). "Fiona Banner's toys for boys are a turn-on at Tate Britain". The Guardian. Archived from the original on 22 October 2013. Retrieved 21 October 2013. the Harrier is in any case named after a bird of prey.
  2. ^ a b c d e Mason 1967, p. 3.
  3. ^ Hay Stevens, James (20 May 1965), "VTOL Aircraft 1965", Flight, 87 (2932), pp. 769–770
  4. ^ Jefford 2006, pp. 21–22.
  5. ^ Spick and Gunston 2000, p. 358.
  6. ^ Jefford 2006, p. 13.
  7. ^ a b c Jenkins 1998, p. 21.
  8. ^ Wood 1975, p. 215.
  9. ^ a b Wood 1975, p. 216.
  10. ^ Buttler 2000, pp. 118–119.
  11. ^ Buttler 2000, p. 120.
  12. ^ Buttler 2000, p. 121.
  13. ^ Mason 1967, p. 7.
  14. ^ Spick and Gunston 2000, p. 362.
  15. ^ "VTOL Aircraft 1966". Flight International, 26 May 1966. p. 884.
  16. ^ Evans 1998, pp. 21–22.
  17. ^ Nordeen 2006, p. 31.
  18. ^ Grove 1987, pp. 319–320.
  19. ^ Duffner, Robert W. (March–April 1984). "Conflict in the South Atlantic: the impact of air power". Air University Review. Maxwell Air Force Base, Alabama: Department of the Air Force. ISSN 0002-2594. Archived from the original on 10 January 2010. Retrieved 18 November 2017.
  20. ^ Sloyan, Patrick J (23 May 1982). "Sea Harrier changes face of air warfare". Tri City Herald.[dead link]
  21. ^ "First Flight for Sea Harrier FRS2". 10 (13). Janes Defense Weekly. 1 November 1988: 767. Cite journal requires |journal= (help)[dead link]
  22. ^ Graves, David (2 April 2002). "Sea Harrier cuts leave the fleet exposed The decision to retire the decisive weapon of the Falklands conflict means the Navy will have to rely on America for air support". The Telegraph. Retrieved 1 January 2014.
  23. ^ Hiranandani 2000, p. 276.
  24. ^ a b Wilson 2000, p. 26.
  25. ^ Nordeen, Lon O. Harrier II, Validating V/STOL. Annapolis, Maryland: Naval Institute Press, 2006. ISBN 1-59114-536-8.
  26. ^ Nordeen 2006, p. 59.
  27. ^ Jenkins 1998, p. 76.
  28. ^ Jefford et al. 2006, pp. 81–82.
  29. ^ Nordeen 2006, p. 68.
  30. ^ "Last trip for one of Britain's iconic aircraft". BBC News. 15 December 2010. Retrieved 15 December 2010.
  31. ^ Wyatt, Caroline. "Struggle at the top over decision to scrap UK Harriers." BBC News, 15 December 2010.
  32. ^ "Harrier Projects". airforce-technology.com. Retrieved: 21 July 2011.[unreliable source?]
  33. ^ Nordeen 2006, pp. 33–34.
  34. ^ Spick 2000, pp. 382–383.
  35. ^ "Air War South Atlantic" by Jeffrey Ethel and Alfred Price published in 1983.
  36. ^ https://www.youtube.com/watch?v=bKQlxCbaRQ4
  37. ^ A View From The Hover My Life In Aviation, John Farley2008, ISBN 978 0 95327 52 5 0, p.81
  38. ^ Brown 1970, p. 83.
  39. ^ a b Jefford 2006, p. 42.
  40. ^ "Hawker Harrier reaction control system" Archived 14 October 2011 at the Wayback Machine U.S. Centennial of Flight, 2003. Retrieved 28 August 2011.
  41. ^ Nordeen 2006, p. 60.
  42. ^ Properly To Test, Book One "The Early Years",Reminiscences Of Flying At The Aeroplane And Armament Experimental Establishment Boscombe Down, Bernard Noble 2003, ISBN 0 9544507 1 X, Chapter 21 Merriman, p.178,179
  43. ^ a b Jefford 2006, p. 41.
  44. ^ Properly To Test, Book One "The Early Years",Reminiscences Of Flying At The Aeroplane And Armament Experimental Establishment Boscombe Down, Bernard Noble 2003, ISBN 0 9544507 1 X, Chapter 21 Merriman, p.178,179
  45. ^ Flight International Magazine, "The Royal Air Force record", 27 August 1977, p.588,589
  46. ^ Markman and Holder 2000, pp. 74–77.
  47. ^ Jenkins 1998, p. 25.
  48. ^ "Securing Britain in an Age of Uncertainty: The Strategic Defence and Security Review" Archived 22 December 2010 at the Wayback Machine. HM Government, 19 October 2010. Retrieved: 19 October 2010.
  49. ^ "Harrier jump jets make final flight from RAF Cottesmore". BBC News,
  50. ^ "Harrier jump-jets sold 'for peanuts'". The Telegraph, 15 June 2011.
  51. ^ "MoD denies sale of Harriers to US" Archived 1 July 2011 at the Wayback Machine. DMJ, 15 June 2011.
  52. ^ Majumdar, Dave (9 June 2012). "USMC hopes new method for tracking fatigue life will help extend Harrier to 2030". Flightglobal. Retrieved 12 August 2012.
  53. ^ "Harrier Production". Harrier.org.uk. Retrieved: 21 July 2011.
  54. ^ "F-35 Lightning II Program Update & Fast Facts"[permanent dead link]. lockheedmartin.com. Retrieved: 26 August 2010.
  55. ^ "Dambusters To Be Next Lightning Ii Squadron". RAF MOD. 18 July 2013. Archived from the original on 15 July 2015. Retrieved 19 June 2015.
  56. ^ Jennings, Gareth (18 June 2015). "UK orders first operational F-35 combat aircraft". Janes Defence. Retrieved 23 November 2014.
  57. ^ Chuter, Andrew. "It’s Official: U.K. To Switch Back to STOVL F-35". Defense News, 10 May 2012.
  58. ^ Nativi, Andy; Menon, Jay; Sweetman, Bill (5 April 2012). "Navies Worldwide Invest In Sea-Based Airpower". Aviation Week & Space Technology. New York: Penton Media. ISSN 0005-2175.
  59. ^ Raghuvanshi, Vivek (21 March 2016). "Indian Navy Retires Sea Harriers". Defense News. Retrieved 21 May 2017.
  60. ^ Wolf, Jim (27 February 2009). "Lockheed says interest growing in F-35 fighter". Reuters. Archived from the original on 4 July 2013. Retrieved 20 July 2011.
  61. ^ Hoyle, Craig (20 July 2010). "Farnborough: Face the Facts with Steve O'Bryan". Flightglobal. Archived from the original on 8 March 2012. Retrieved 31 October 2011.
  62. ^ Ing, David (28 May 2014). "Spain to extend AV-8B Harrier service life". Jane's Defence Weekly. Surrey, UK: Jane's Information Group. 51 (27). ISSN 0265-3818.
  63. ^ Indian Navy Retires Sea Harriers 21 March 2016. Accessed 3 April 2016.
  64. ^ "Archived copy". Archived from the original on 14 July 2012. Retrieved 26 October 2013.CS1 maint: archived copy as title (link)
  65. ^ "Technical" page on harrier.org.uk website, viewed 2013-11-24
  66. ^ Nordeen 2006, Appendix C.

BibliographyEdit

Further readingEdit

External linksEdit