A pre-production derivative of the P.1127 was built as the Kestrel, and the full production type as the Harrier, with a turbofan of 21,500 pounds nominal thrust. Installed thrust is around 18,000 to 18,900 pounds, but if the Harrier’s weight is kept fractionally below that figure, it will be able to take off and land vertically and hover in between. In practice, however, vertical takeoff is seldom employed, since a forward roll of only a few hundred feet adds several thousand pounds to the permissible weight and payload by the addition of wing lift. Since the Harrier is designed to operate from any reasonably firm and smooth surface away from airfields, STO invariably presents no problems. Having used up most of its 5,000 pounds of internal fuel and dropped up to 7,000 pounds or more of external ordnance, the Harrier can then return for a standard vertical landing into a clearing or onto a pad only a few feet bigger than its 25 foot three inch span and 45 foot six inch fuselage.
The first of six development Harriers was flown on 31 August 1966 and the first production aircraft flew in December 1967. The type entered service with the Royal Air Force with 1 Squadron at Wittering in July 1969.

Hawker HS.1127 Harrier Article

The two seat Harrier is more than 10 feet longer, not only because of the extra cockpit section, which adds 47 inches to the forward fuselage, but also because of the 33 inch rearward extension of the vertical tail for aerodynamic balance. The remaining extra length results from the need to move the tail reaction control valve (RCV) farther aft to maintain its effectiveness without draining the Pegasus of excessive amounts of bleed air. Since the Harrier can go on flying at speeds down to zero, or even backward, its aerodynamic control surfaces have to be supplemented by reaction controls or jet thrusters. Linked to the stick and rudder pedals, these use bleed air from the Pegasus compressor to RCVs at each wingtip and in the nose and tail, producing the correct aircraft response in pitch, roll and yaw. They automatically come into operation when the engine nozzles are deflected downward through 20 degrees or more and are designed to maintain a progressive feel and response from wingborne to jetborne flight without too much of a power loss from the Pegasus.

All Harriers have a sideslip vane just in front of the cockpit that (in addition to providing a visual reminder of the aircraft’s attitude) is linked to the rudder pedals. When critical combinations of sideslip and airspeed (between 30 and 100 knots) are approached, the appropriate rudder pedal starts vibrating as a reminder that it might be a good idea to apply some boot to it if you want to remain right side up. The autostabilizer also helps in this respect.
For ground maneuvering, the nosewheel of the Harrier’s bicycle landing gear steers hydraulically via the rudder pedals from a flip of a trigger on the stick. With this system, and with the nozzles at 45 degrees to reduce its high idling thrust, the Harrier will turn almost in its own length, kept steady by its wingtip outrigger legs.

There seems to be no real reason why the Harrier should accidentally spin during combat, since it can go on flying with jet deflection below normal wingborne stalling speeds. It can instantly halve its turning radius by the use of vectoring in forward flight.

First flown on 28 December 1967, the GR.1 is the single-seat close-support and reconnaissance version for the RAF, which has also ordered the two-seat T.2 for operational training.
The Harrier GR Mk.1 was the first production model taken from the Kestrel and entered service with the RAF on April 1, 1969. Construction took place at factories in Kingston-upon-Thames in southwest London and at Dunsfold, Surrey. The latter adjoined an airfield used for flight testing; both factories have since closed.

The Harrier’s max low level speed is not greatly reduced by the carriage of external stores, since the main limitation on its speed is the drag from its huge intakes. These are required to enable the engine to obtain the necessary mass flow of air in the hover with no forward speed, or even flying backwards.
Normal attack speed is 450 kts or 480 kts depending on configuration. Weapons include 30mm cannon, 1000 lb free-fall or retard bombs, CBU (cluster bomb unit carrying 247 armour-piercing bomblets), SNEB (pod with 19 x 68mm rockets), and laser-guided bombs. The Sea Harrier can also carry anti-shipping missiles of the Harpoon/ Martel type. Sidewinder AAM (9L) may be carried for air combat.
The avionics carried includes INAS (Inertial Navigation Attack System), which provides weapon aiming information through the Head-up Display (HUD); navigation via computer and moving-map display; and instrument flying information via HUD. Other equipment includes Laser ranger and marked-target seeker, radar warning receiver, reconnaissance camera, voice recorder, IFF/SSR, Tacan, and, Martin Baker Mk 10 ejection seat. This rocket-assisted seat has a zero-zero capability.
The GR.Mk 1A was an upgraded version of the GR.Mk 1, the main difference being the uprated Pegasus Mk 102. 58 GR.Mk 1As entered RAF service, 17 GR.Mk 1As were produced and a further 41 GR.Mk 1s were upgraded.
The Harrier GR3 was a development of the Harrier GR1, being fitted with improved attack sensors, electronic countermeasures and a more powerful Pegasus Mk 103 engine over the GR1.
The Harrier GR3 was utilised by the Royal Air Force as a ground attack and reconnaissance aircraft in the Close Air Support role (CAS). RAF Harriers were deployed to the Royal Navy aircraft carrier HMS Hermes, as part of the Task Force sent to recapture the Falklands Islands. The Harrier GR3 performed attack sorties from the aircraft carrier, and later from basic landing strips on the islands, often in conditions that would have grounded conventional aircraft. Ten Harrier GR.3s from this 1 Squadron operated with Royal Navy Sea Harriers in the Falklands Conflict in 1982, flying 150 missions. Three of these aircraft were lost.

In addition to operations with RAF Germany, the Harrier GR3 has also seen service with the Royal Air Force in Norway and Belize.
The GR.5 features a new nose shape housing a Hughes angle rate bomb set greatly improving target acquisition and weapon aiming capabilities, a McDonnell-Douglas manufacture carbon fibre wing 20% larger than the GR.3, leading edge root extensions which provide a better turn rate, retractable refueling probes and a new wrap-around front windscreen panel.

The first Harrier GR.7, a converted GR.5, first flew on 26 November 1989.

The Royal Navy version of the Harrier, the Sea Harrier, is basically the same airframe fitted with dif-ferent equipment. British Aerospace handed over XZ451, the Royal Navy’s first Sea Harrier, at BAe Dunsfold on 18 June, 1979. The cockpit has been raised to improve rearward visibility, and to accommodate the Blue Fox radar. The cockpit radar display is a TV-tube conveying flight information as well as air-air and air-surface radar. The navigation system is based on an attitude reference platform with a radar input. The Sea Harrier provides the RN with an air defence, recce and strike/attack capability. As an air defence fighter, it’s effectiveness is partly in its quick reaction time. There is no necessity to turn the carrier into wind as with conventional aircraft, and no need for time-consuming catapult launches. This, plus the Harrier’s built-in starting system, means a scramble take-off within 2 minutes of an alarm. Once airborne the high-altitude intercept radius is 400 nm, with 3 minutes full throttle combat, and vertical landing recovery on the ship. In the reconnaissance role, the Sea Harrier can carry out electronic and visual surveillance, covering approx 20,000 sq miles in one hour at low level.

The ski-jump technique for STOL use by Harriers launched from Royal Navy aircraft carriers was tested at the Royal Navy’s airfield at Yeovilton, Somerset. Their flight decks were designed with an upward curve to the bow following the successful conclusion of those tests. The ski-jump on the carriers provides an improvement in take-off performance. Launched off the end of the ski-jump, with the nozzles deflected to approx 50 degrees at the moment of departure, the Harrier flies a partly ballistic trajectory for some seconds, during which time it is jet-borne while accelerating as the nozzles are gradually moved aft again. This reduces the take-off distance required. Additionally if the ship is pitching in bad weather, it ensures the aircraft never leaves the carrier pointing at the water. The ski-jump enables 1500 lb more load to be carried, or 200 feet less ground roll to be used, than flat-deck equivalents.

The Indian Sea Harrier FRS.51s (plus two T.60s) differ from standard RN Sea Harriers only in using gaseous rather than liquid oxygen, modified radar and avionics, and provision for Matra Magic AAMs rather than AIM-9 Sidewinders. The T Mk 60 two-seaters are more extensively modified, with Sea Harrier-type cockpits and most of the Ferranti NAVHARS nav-attack system.
Export versions, which have the more powerful Pegasus II engine, are desig¬nated Mk 50 (single seat) and Mk 51 (2 seat). US Marine Corps designation is AV 8A.
The first Hawker Siddeley AV 8A Harrier for the Spanish navy was flown at Dunsfold, Surrey, on 18 September 1975. Known as the Matador in Spanish service, these aircraft were shipped to the USA for pilot training before embarkation in the carrier Dedalo. All 11 (plus two two seat TAV 11As) had been handed over by November 1975.

McDonnell Douglas / BAe AV-8 Harrier II
The marine corps first Harriers were Hawker Siddeley-built AV-8As delivered between 1970 and 1976. The AV-8A and the RAF’s Harrier GR.I had much in common, including the RAF camouflage colors and pattern. The upper surfaces were a disruptive pattern of RAF Dark Green (641) and Dark Sea Grey (638) with undersurfaces in Light Aircraft Grey (627). For repainting, the Marines chose dark olive green FS 34064 and dark gray FS 36099 for the uppersurface camouflage, with Light Gull Gray FS 36440 underneath.

The prototype AV-8B, converted from an AV-8A, first flew on November 9, 1978, and the first of four full-scale development aircraft followed on November 5, 1981. Production deliveries to the USMC began in October 1983, and the first unit became operational in January 1985. USMC deliveries will continue into the 1990s, against a requirement for 300 AV-8Bs and 28 TAV-8Bs.
The No 2 VAV 8B, modified by McDonnell Douglas from a British built AV 8A Harrier, was fitted with leading edge root extensions (LERX) of the type already test¬ flown on a Harrier GR Mk 3 under MoD contract. The LERX serve to increase the turn rates of the AV 8B from a figure of about 14 deg/sec to at least 16 deg/sec.
The improved AV-8B Harrier II is a MeDonnell Douglas design, produced in the U.S. Two YAV-8Bs (modified from AV-8A airframes) were painted in red, white, black, and gold high-visibility schemes. The first of four Full-Scale Development airframes came in standard RAF camouflage; the second came in another, high-visibility scheme. The third FSD AV-8B was painted in the RAF pattern, but with Marine Field Green FS 34095 and Blue Gray FS 35237 uppersurface colors with FS 36440 undersides. This color change was evidently an attempt to economize by using standard Navy/ Marine colors.
The fourth development Harrier II received a counter-shaded hree-tone gray camouflage similar to the Navy’s other TPS schemes. Its colors were FS 36375 Light Ghost Gray on top, FS 36440 on the sides, and FS 36495 light gray on the bottom. The Marines applied the FS 34064/36099/36440 scheme to the first 25 production Harrier IIs. After reviewing the AV-8B’s tactics, the Corps adopted a wraparound scheme beginning with the 26th airframe, serial number 162081. The camouflage pattern was continued on the undersurfaces, and FS 36440 was eliminated.
Spain has ordered 12 EAV-8Bs to supplement its fleet of AV-8A Matadors from late 1987. British Aerospace manufactures some 40 per cent of the AV-8B airframe.
Two Harrier GR.5 development aircraft, the first of which flew on April 30, 1985, will be followed by 60 production aircraft. Deliveries to the RAF began in July 1987, and long-lead authorisation has already been approved for up to a further 27 aircraft. British Aerospace manufactures 50 per cent of each GR.5 airframe.

The cockpit of the AV-8B is similar to that of the Harrier GR.5, but has a second multi-function didplay instead of the moving map display.

The decision to put the much improved Harrier II into production was taken in August 1981; initial plans calling for 257 American and 60 British aircraft. Since then the requirements have increa¬sed to 328 and 96 aircraft respectively, the American total including 28 TAV-8B two-seat conversion and proficiency trainers. An initial 27 of these aircraft were ordered in 1984. The first of them flew in October 1986, and the type’s service debut came in March 1987.
A two-seat operational trainer version of the Harrier II, designated TAV-8B for the USMC, flew on October 21, 1986, and deliveries began on schedule in March 1987. The TAV-8B has a forward fuselage lengthened by 4 ft (1.22 m) by comparison with that of the AV-8B to allow the incorporation of a second seat in the standard vertically staggered arrangement. This increases structure weight by 1,325 lb (601 kg), but the TAV-8B still possesses full combat capability in the form of an underfuselage cannon and six underwing hardpoints for dispo¬sable ordnance. In 1990 the British decided to procure 10 similar two-seater conversion trainers with the designation Harrier T.Mk 10. The TAV-8B also has a taller fin than the single-seat AV-8B. The development of a night attack capability for USMC AV-8Bs continues, and a prototype flew in June 1987, with deliveries following in 1989. Night attack equipment includes a Flir system, night vision goggles for the pilot, and a modified headup display.

For the 1991 ‘First Flights’ television series, Neil Armstrong flew the Harrier.

Gallery

GR.1
Engine: One 19,000 lb (8,618 kg) st Rolls Royce Bristol Pegasus Mk 101 vectored thrust turbofan
Wing span: 25 ft 3 in (7.70 m)
Length: 45 ft 8 in (13.92 m)
Height: 11.253 ft / 3.43 m
Gross weight: over 22,000 lb (9,979 kg)
Max. speed: over 720 mph (1,159 km/h)
Service ceiling: 49213 ft / 15000 m
Crew: 1
Armament: Two 30 mm Aden gun pods / max 2268kg
Max. endurance: over 7 hr with in flight refuelling.

GR-3
Engine: Bristol Siddeley Pegasus II Mk.103, 21,500 lb / 9752 kg thrust.
Wing span: 25 ft 3 in / 7.70 m ( 29 ft 8 in / 9.04 m w/ferry tips)
Length: 46 ft 10 in / 14.27 m
Height: 11 ft 4 in / 3.45 m
Wing area: 201.1 sq.ft / 18.68 sq.m (216.0 sq.ft / 20.075 sq.m w/ferry tips)
Empty wt: 13,535 lb / 6139 kg
MAUW: 25,200+ lb / 11,431+ kg
Max speed: M1.2; at low level approx 600 kts. / 737+ mph / 1186+ kph
Ceiling: 50,000+ ft / 15,240+ m
Time to climb brakes off to 40,000 ft: 2 min 20 sec.
Initial ROC: 30,000 fpm.
Range: 828 mi / 1316 km
External store load 8,000 lb / 3269 kg
Armament: 2 x 30mm Aden cannon pods.

GR-5
Armament: 2 x 30 mm cannon

Sea Harrier FRS.51

T.60

British Aerospace Sea Harrier FRS.1
Engine: Rolls-Royce Pegasus II Mk.104, 9752 kg / 21,500 lb
Wingspan: 7.7m / 25 ft 3 in
Length: 14.5 m / 47 ft 7 in
Height: 12 ft 2 in / 3.71 m
Wing area: 201.1 sq.ft / 18.68 sq.m
Empty weight: 13,100 lb / 5942 kg
MTOW: 26,190 lb / 11,880 kg
Max speed: 1191 kph / 740 mph
Range: 920 mi / 1480 km
Ceiling: 50,000+ ft / 15,240+ m
Armament: 2 x 30 mm Aden / 150 rds
Max external load: 8000 lb / 3630 kg
Seats: 1

AV-8A

McDonnell Douglas / Bae AV-8B Harrier II
Engine: Rolls-Royce F402-406 (Pegasus 11-21 / Pegasus 105) vectored turbofan, 22,000 lb / 95.8 kN
Wingspan: 30 ft 4 in / 9.25 m
Length: 46 ft 3 in / 14.12 m
Height: 11.483 ft / 3.5 m
Wing area: 230.35 sq.ft / 21.4 sq.m
MTOW: 29,750 lb / 13,495 kg
Weight empty: 13986.3 lb / 6343.0 kg
Max. payload weight: 17016.0 lb / 7717.0 kg
Wing loading: 134.69 lb/sq.ft / 657.0 kg/sq.m
Max speed: 673 mph / 1083 kph
Cruising speed: 470 kts / 870 kph
Initial climb rate: 14763.78 ft/min / 75.0 m/s
Service ceiling: 43307 ft / 13200 m
Fuel internal: 4260 lt
Range: 961 nm / 1780 km
Air refuel: Yes
Ferry range: 3310 sm / 5327 km
Armament: 1 x 25 mm cannon (300 rds)
Hard points: 7
External load: 17,000 lb / 7711 kg
Crew: 1

TAV-8B Harrier II
Engine: one 21,550-lb (9,775-kg) thrust Rolls-Royce F402-RR-406 (Pegasus 11- 21) vectored-thrust turbofan.
Maximum speed 647 mph (1,041 km/h) at sea level
Service ceiling 50,000+ ft (15,240+ m)
Radius 553 miles (890 km) with no loiter
Empty weight 14,075 lb (6,384 kg)
Maximum take-off weight about 29,750 lb (13,494 kg)
Wing span 30 ft 4 in (9.25 m)
Length 50 ft 5 in (15.37 m)
Height 13 ft 5 in (4.09 m)
Wing area 230.0 sq ft (21.37 sq.m).
Armament: one 25-mm multi-barrel cannon, and up to about 15,500 lb (7,031 kg) of disposable stores.
Seats: 2