DEVELOPMENT

Without the Sea Harrier, the Falkland Islands would still be in Argentinian hands. Like all wars, the Falklands cam­paign of 1982 was finally won by the infantry, but without the air cover given to the UK task force by Royal Navy Sea Harrier fighters, the fleet could not come within range of the Argentinian A-4s and Mirages, and the landings would not have been possible. Sea Harrier FRS Mk 1 is a multirole, shipborne V/STOL fighter able to perform attack, reconnaissance, and air superiority missions.

The first serious evidence that Harriers might one day fly from RN carriers came in March 1970, when GR.l fighters of No. 1 Sqn of the RAF flew trials sorties from HMS Ark Royal. Dogged persistence by some Royal Navy planners who wanted to see a reversal of the 1966 decision by a Labour Government to end RN fixed-wing flying finally paid off late in August 1972 with the issue of a Naval Staff Target for a minimal-modification version of the Har­rier GR.3 able to operate from "Invinc-ible"-class light carriers. An order for 24 aircraft was repeatedly delayed, and was not placed until May 1975. First flight was in August 1978, with delivery of the first aircraft to the Royal Navy taking place in June 1979.

India's long-standing requirement for new aircraft to replace the totally obsoles­cent Sea Hawk fighters originally deploy­ed aboard the carrier Vikrant was finally met by ordering eight Sea Harriers—six FRS Mk 51 single-seaters and two T Mk 4 trainers. Total value of the contract is estimated to be worth over $90 million. Deliveries began on January 27, 1983, and all aircraft are to become operational aboard the Vikrant. An option on a further batch of eight aircraft has not yet been taken up.

Having lost five Sea Harriers during the Falklands war and two others in acci­dents, the Royal Navy placed a follow-on order for 14 further aircraft-seven to replace losses plus a further seven to increase the fleet size following the deci­sion not to sell Invincible to the Royal Australian Navy. Production is running at around one aircraft per month, and is likely to end in the mid-1980s.

Soon after the Falklands war BAe was reported to be studying the feasibility of a specialised airborne early-warning ver­sion. This would have had extended wings equipped with conformal radar an­tennas. There have been no subsequent reports of this project, so it has probably been abandoned.

The need for some improvements to Sea Harrier was highlighted by the Falklands campaign. The need for greater endurance and weapon-carrying capability was swift­ly met by fitting aircraft embarked aboard the carrier Illustrious with larger drop tanks and four Sidewinders instead of two. In the longer term, the RN plans improvements to the Ferranti Blue Fox airborne radar and to the aircraft's radar-warning receiver.

As part of a mid-life improvement pro­gramme, RN Sea Harriers will be equipped with a new Ferranti pulse-doppler radar, plus up to four AIM-120 AMRAAM miss­iles and two AIM-9 Sidewinders, giving the aircraft a multi-shot look-down/shoot-down capability. Two drop tanks fitted to underwing pylons would increase the air­craft's endurance, improving range and loiter capability. New leading-edge root extensions (LERXs) could improve man­oeuvrability, and an improved radar warn­ing receiver may also be fitted.

STRUCTURE

The Sea Harrier has great commonality with the airframe, powerplant and mechanical systems of the Harrier GR.3 but has an entirely different nose and forward fuselage, a larger fin to allow for this, and magnesium alloy has been large­ly eliminated from the airframe as an anti-corrosion precaution.

Air turbulence caused by ship super­structure can be a problem in naval avia­tion, so the Sea Harrier has greater control authority while in the hover and transi­tion—the reaction-control jets are more powerful than those on Harrier. The fin has been increased in height by around 4in (10cm), while the horizontal stabiliser has been strengthened and given an extra 2deg of travel.

The cockpit has been raised to incorpo­rate revised displays and to give a better rear view, while the nose is increased in size to house the Blue Fox radar. The nose, complete with its radar set, may be hinged to port for storage within the carrier's hangar. Other minor modifications to the Sea Harrier added an emergency wheel-brake system, a different pattern of liquid-oxygen converter, and various lashing lugs on the nosegear.

POWERPLANT

The Sea Harrier is powered by the Pegasus 11 Mk 104. A marinised version of the Mk 103 used to power the RAF's GR.3 fleet, this offers the same 21,000lb (9,500kg) of thrust but incorporates LP and intermedi­ate casings made from corrosion-resistant materials, and has a strengthened gearbox able to drive the more powerful 15kVA electrical generators of the naval aircraft.

AVIONICS

When the Royal Navy decided to adopt a navalised version of Harrier as its next shipboard fighter, part of the navalisation process involved the addition of a virtual­ly all-new avionics suite to what was originally a low-level strike aircraft. This includes a Ferranti Blue Fox radar, a Smiths Industries head-up display of im­proved design, a self-aligning Ferranti FIN 1040 attitude and heading reference system and digital computer, a Decca 72 Doppler radar, radar altimeter, and im­proved radar warning system.

Blue Fox was developed from the earlier Seaspray set devised for the Sea King helicopter. This is a frequency-agile I-band dual-role set, and can be used to guide the aircraft during interception mis­sions or during attacks against surface targets. The four main operating modes are search (for target detection), attack (for use against air and surface targets), boresight (used for ranging on targets of oppor­tunity), and transponder (for the identi­fication of "friendlies").

Pulse-Doppler techniques are not used, since this technique—widely used in cur­rent-generation radars—is mainly in­tended to improve rejection of ground clutter. Blue Fox was designed for the simpler role of detecting large targets such as Backfire bombers or 11-38 May mari­time-patrol aircraft over the sea.

The antenna is a stabilised planar array, and the basic set is built up from a series of LRUs in order to ease maintenance. It is air-cooled and weighs 186lb (84kg).

ARMAMENT

Being a modified version of the land-based fighter, the Sea Harrier can carry the same range of ordnance as RAF GR.3s. Since air-to-air combat was always seen as one of Sea Harrier's roles, Royal Navy aircraft were fitted with AIM-9 Sidewinder miss­iles and are scheduled to receive the AIM-120 AMRAAM. Indian Navy FRS.51 air­craft carry the Matra R.550 Magic. All versions carry two 30mm ADEN cannon in ventral packs.

One weapon not carried by the GR.3 but an important part of Sea Harrier's arma­ment is the new BAe Dynamics Sea Eagle, an anti-ship missile based on the proven aerodynamic form of the earlier rocket-powered Anglo-French Martel. It is prob­ably the most advanced anti-ship missile currently available, and likely to remain so for some time in view of the long delays likely before supersonic weapons such as the Franco-German ANS fly in definitive form and are cleared for service.

Flight trials have demonstrated the round's ability to separate from the launch aircraft at various altitudes, light up the built-in turbojet engine, descend to low level, then fly under autopilot control to the point where the built-in MSDS radar seeker can take over for the final run in to the target. Seeker performance in the face of ECM has also been demonstrated, while warhead penetration and detonation tests have confirmed the likely destructive effect.

PERFORMANCE

The Royal Navy Air Staff Target for Sea Harrier asked for a fighter able to fly a 400nm (740km) tactical radius air-to-air mission, a strike mission of at least 250nm (460km) tactical radius, or a search mis­sion covering at least 27,000 square miles (70,000sq km) at low level.

Test flights carried out in the early 1970s by company pilots showed that, as on land, a short take-off run greatly im­proves load-carrying capability. In the case of a shipboard fighter, the wind over the deck resulting from the carrier's own speed gives a further performance boost if STOL takeoffs are used. The most drama­tic improvement comes with the use of a "ski-lift" take-off ramp. The aircraft can take off with a heavier load of fuel and weapons, or from a shorter take-off run, if the toward roll ends on a curved ramp which will give a degree of upward momentum. The aircraft can leave the ramp without the speed and wing lift needed for sustained flight. While in what amounts to a semi-ballistic flight, it can gain normal flying speed.

Tests with a land-based ramp started in August 1977, and angles of up to 20 deg were used, though it was established that the optimum was around 15deg. The basic procedure is simple. Aircraft begin their take-off roll with the nozzles pointing aft, and the pilot applies a downward nozzle angle as he reaches the top of the ramp.

A ramp was added to the carrier Invinc­ible while the vessel was still under con­struction, and was incorporated in the design of follow-on vessels. The 1950s-vintage Hermes was also retrofitted with a ramp. The top speed of Sea Harrier is 640kt (l,190km/h) at sea level, but the aircraft can manage Mach 1.25 in a dive. Normal cruise speed is 350 to 450kt (650 to 835km/h) at low altitude, but the massive thrust of the Pegasus allows a swift accel­eration to 600kt (l,110km/h). At height, the aircraft can comfortably cruise on internal fuel for up to an hour at Mach 0.8. Service ceiling is 51,200ft (15,600m). Reaction time is fast: from the moment of scramble the aircraft can arrive at a combat area 30km (55km) from the carrier in less than 6 minutes.

During the Falklands war 28 Sea Har­riers flew 1,100 combat air patrol missions plus 90 offensive support operations. Availability at the beginning of each day was 95 per cent, and 99 per cent of all planned missions were flown. On April 1, 1982, Hermes launched 12 Sea Harriers to carry out attacks on Port Stanley and Goose Green. An hour after their return, the same aircraft were once more airborne on air-defence patrols.

In action against the Argentinian Air Force, Sea Harriers scored 20 "kills" and three probables, despite being outnum­bered six to one. The AIM-9L Sidewinder air-to-air missile dominated in air-to-air combat, accounting for 16 of the "kills" plus one probable. The other enemy air­craft were shot down by 30mm cannon fire from the Sea Harrier's twin ADEN. Two Sea Harriers were lost in combat— one to small-arms fire and the other to a Roland surface-to-air missile. Four more were lost in accidents—one crashed after take-off, two went missing while on patrol and are believed to have collided in bad weather, while another rolled off the deck and into the sea.

OPERATORS

UK (34 FRS Mk 1 and 4 T Mk 4 trainers originally delivered; 14 more aircraft or­dered); India (6 FRS Mk 51, two T Mk 4 trainers).