The Hawker Siddeley Harrier GR.1/GR.3 and the AV-8A Harrier are the first generation of the Harrier series, the first operational close-support and reconnaissance fighter aircraft with Vertical/Short Takeoff and Landing (V/STOL) capabilities. The Harrier was the only truly successful V/STOL design of the many that arose from the 1960s.
In the 1970s, the Harrier was developed into the radar-equipped BAE Sea Harrier for the Royal Navy. The Harrier was also extensively redesigned as the BAE Harrier II and AV-8B Harrier II, which were built by British Aerospace and McDonnell Douglas.
The immediate development of the P.1127 was the Hawker Siddeley Kestrel FGA.1, which appeared after Hawker Siddeley Aviation was created. The Kestrel's first flight was on 7 March 1964. It was strictly an evaluation aircraft, and only nine were built. These equipped the Tripartite Evaluation Squadron formed at RAF West Raynham in Norfolk, numbering 10 pilots from the RAF, USA and West Germany. One aircraft was lost but the remainder transferred to the U.S. for evaluation by the Army, Air Force and Navy, designated XV-6A Kestrel.
At the time of the development of the P.1127, Hawker had started on a design for a supersonic version, the Hawker P.1154. After this was cancelled in 1965, the RAF began looking at a simple upgrade of the Kestrel as the P.1127 (RAF).
An order for 60 production aircraft was received from the RAF in mid-1966, and the first pre-production Harriers, then known as the P.1127 (RAF) were flying by mid-1967, becoming known as Harrier GR.1.
The ski-jump technique for STOVL use by Harriers launched from Royal Navy aircraft carriers was tested at the Royal Navy's airfield at RNAS Yeovilton (HMS Heron), Somerset. Their flight decks were designed with an upward curve to the bow following the successful conclusion of those tests.
The Harrier GR.3 featured improved sensors (such as a laser tracker in the lengthened nose), countermeasures and a further upgraded Pegasus Mk 103 and was to be the ultimate development of the 1st generation Harrier.
The AV-8As of the United States Marine Corps were very similar to the early GR.1 version, but with the more-powerful engine of the GR.3. The aircraft was powered by a 21,500 lbf (95.6 kN) thrust Roll-Royce Pegasus Mk 103 (F402-RR-402) turbofan engine. The AV-8A was armed with two 30 mm ADEN cannons (podded under the fuselage) and two AIM-9 Sidewinder air-to-air missiles. A total of 113 were ordered for the US Marines and the Spanish Navy.
The Harrier was also a manoeuvrable and a potent air-to-air fighter, being able to out-manoeuvre other fighter aircraft then in service. The air combat technique of vectoring in forward flight, or "viffing," was formally developed by the USMC in the Harrier to outmanoeuvre a hostile aircraft or other inbound weapons.
In addition to normal flight controls, the Harrier has a lever for controlling the direction of the four vectorable nozzles. The nozzles point rearward with the lever in the forward position for horizontal flight. With the lever back, the nozzles point downward for vertical takeoff or landing.
Harrier GR.3s were operated by the RAF from Hermes, and provided close support to the ground forces and attacked Argentine positions. but were unable to destroy the Stanley runway. If most of the Sea Harriers had been lost, the GR.3s would have replaced them in air patrol duties. Four Harriers GR.3s were lost to ground fire, accidents, or mechanical failure. The RAF Harriers would not see further combat, as the Hawker Siddeley airframes were replaced by the larger Harrier II developed jointly by McDonnell Douglas and British Aerospace.
Harrier GR.1 : The first production model derived from the KestrelHarrier GR.1A : Upgraded version of the GR.1, the main difference being the uprated Pegasus Mk 102 engine. Fifty-eight GR.1As entered RAF service, 17 GR.1As were produced, a further 41 GR.1s upgraded.Harrier GR.3 : Featured improved sensors (such as a laser tracker in the lengthened nose and radar warning receiver on the fin and tail boom) and a further uprated Pegasus Mk 103. It was to be the ultimate development of the first-generation Harrier. The RAF ordered 118 of the GR.1/GR.3 series.Harrier T.2 : Two-seat training version for the RAF.Harrier T.2A : Upgraded T.2, powered by a Pegasus Mk 102.Harrier T4 : Two-seat training version for the Royal Air Force, equivalent to the GR.3.Harrier T4N : Two-seat training version for the Royal Navy.Harrier Mk 52 : Two-seat company demonstrator, one built.AV-8A Harrier : Single-seat ground-attack, close air support, reconnaissance, and fighter aircraft; similar to the earlier GR.1, but with the GR.3 engine. 113 ordered for the U.S. Marines. Company designation Harrier Mk 50.AV-8C : Upgraded AV-8A for the U.S. Marine Corps.AV-8S Matador : Export version of the AV-8A Harrier for the Spanish Navy, later sold to the Royal Thai Navy. Spanish Navy designation VA-1 Matador. Company designation Harrier Mk 53 for the first production batch, and Mk 55 for the second batch.TAV-8A Harrier : Two-seater training version for the US Marine Corps. The TAV-8A Harrier was powered by a 21,500 lb Rolls-Royce Pegasus Mk 103 turbofan engine. Company designation Harrier Mk 54.TAV-8S Matador : Export version of the TAV-8A Harrier for the Spanish Navy. Later sold to the Royal Thai Navy. Spanish Navy designation VAE-1 Matador. Company designation Harrier Mk 54.
The Harrier's unique characteristics have led to it being featured a number of films and video games.