The British Aerospace Harrier is the only successful VSTOL (Vertical/Short Take Off and Landing) aircraft in the world with the United States, Spain and Thailand also operating other variants. The development of the unique jet began in 1960 when the Hawker P.1127 made the first vertical take off using a unique system of vectored nozzles. Six of these prototypes were made with one being lost during an air display.
1964 saw the concept develop when the Kestrel FGA.1 made it's first flight which led to 9 aircraft constructed purely to evaluate vertical jet flight.
It was around this time Hawker began designing a supersonic version of the Kestrel known as the Hawker P.1154. In 1965 however, the idea was scrapped and the RAF looked at upgrading the Kestrel. The Royal Air Force placed an order in 1966 for 60 of these upgraded aircraft known as the Hawker P.1127 which would then go to named Harrier. These new aircraft entered service a year later and was designated the Harrier GR.1
The Harrier GR1 - the first version of the aircraft in RAF service, first flew on the 28th December 1967 and entered service two years later on 1st April 1969. 41 GR1's were later upgraded with better engines to GR1A's along with 17 brand new airframes. Predictably, a few years later the GR1A was upgraded to GR3 which provided improved sensors such as laser trackers in the extended nose and a radar warning receiver on the tail.
The GR5 was the Royal Air Force's first "second generation" Harrier,Two AV-8s (An export version) were modified to "Harrier II" (Harrier Second Generation) standard in 1979 which were used as development aircraft. It was two years later that the first proper GR5 made it's maiden flight on 30th April 1985 and entered service in 1987 with 41 airframes. 21 aircraft were later upgraded to GR5A standard.
May 1990 saw the Harrier GR7's first flight with it's first detachment on an Invincible class Aircraft Carrier in 1994. The GR7 saw it's first piece of action in 1995 over the former Yugoslavia. The first sea deployment followed in 1997 in cooperation with the Royal Navy's Sea Harrier. This alliance was given the name "Joint Force Harrier".
Following the trend, the GR7 was upgraded to GR7A which was a first stage to the planned GR9. The GR7A's most noteable difference was the uprated Pegasus 107 engine. This improvement gave the aircraft increased performance in 'hot and high' conditions and operating from Aircraft Carriers.
The GR9 was to be the final variant the Harrier. Remarkably, a few GR7 versions remained in service until March 2010.
The GR9 brought a lot of Avionic and weapon changes. This upgrade was named the IWP (Integrated Weapons Programme)
This welcomed the Brimstone, Maverick, Paveway III Laser Guided Bomb and Paveway IV Precision Guided Bomb. To compliment the array of weapons, the Lockheed Martin Sniper Advanced Targeting Pod (ATP) was also put on to the GR9.
The GR9A was the upgraded GR7A and featured the same uprated engines of the GR7 but also featured the GR9's new avionics and weapons. Due to a shortage of the uprated Pegasus 107 engines they kept the rest of the fleet with the Pegasus 105.
The only way to learn to fly a single seat fighter was to learn in a two seat version. This led to the Harrier T2 to teach pilots to fly the GR1. This in-turn was upgraded to the T4 when the GR3 was brought into service and then T10 for the GR7. With the massive change of the GR9's cockpit, the T12 was completely refreshed with the avionics and weapons that the GR9 possessed.
Running parallel to the conventional Harrier GR models, the Royal Navy operated the Sea Harrier from 1981 until 2006.
The Sea Harrier came about when the Hawker Siddeley P.1127 Kestrel (mentioned earlier) commenced trials on HMS Ark Royal in 1963. This showed just how well the Kestrel/Harrier performed on a ship's deck. Eventually, on 20th August 1978 the first Sea Harrier was flown at Dunsfold airfield but it was 3 years later in 1981 when it was first put into service on HMS Invincible. The Sea Harrier became famous for it's work during the Falklands War where it shot down 20 Argentine aircraft by air-to-air combat without a single Harrier loss.
The main differences between the Sea Harrier and the conventional Harrier was primarily it's size, including smaller wings. It had a re-shaped nose to fit the Ferranti Blue Fox radar and a higher ejection seat. The pitot probe was raised to the tail and the nose camera transferred from the left hand side to the right.
From the Harrier GR5 onwards (Second Generation Harriers) an aerodynamic one-piece canopy was used. This enabled rain to slip past the curved cockpit without disturbing the Pilot's view. Earlier models had a flat front panel to see-through. A feature that the Sea Harrier retained. To clear the Pilot's view a window wiper was added to the front and also a wind deflector which can be seen in the image above.
The most obvious feature in the image is the large pole in front of the cockpit window. This is a Wind-vane that helps the pilot keep the aircraft pointing in the direction of air-flow.
In slow speed flight the airflow over the aircraft can become very un-predictable for example changes in the wind such as gusts or obstacles diverting the wind-flow. If the Harrier 'side-slips' too far, known as about 10° from the aircraft's forward momentum then the aircraft may end up going into an un-recoverable roll. The pilot can monitor the side-slip by keeping an eye on the wind-vain. If the angle of side-slip starts to become a problem, the pilot is notified by a pedal-shaker which shakes the rudder pedals.
The Harrier uses four nozzles (two on each side) to vector thrust from it's single engine to control speed and control. When the nozzles point downwards (As seen in the image above) the Harrier balances on the four columns of air. The nozzles can be directed up to 98° allowing the Harrier to even fly backwards.
To control the Harrier in the hover there are a series of reaction control nozzles. Firstly one under the nose helps to stabilize the aircraft in the hover, the wingtip ducts blow up or down which enables a small amount of roll which will move the aircraft sideways. There are also ducts behind the tail (Image below) to yaw the aircraft so it can turn in any direction on the spot (bottom right image). The tail ducts blow down, right and left. For a Harrier to bow or fly nose down, the tail duct would be blowing more than the nose and to go backwards it would be vice versa.
The Harrier GR9 cockpit features a huge array of features designed to ease the workload of the pilot during flight. The Harrier has a HOTAS system (Hands on throttle and stick) which means the pilot can operate almost everything using the buttons on his stick and throttle without having to move his hands anywhere else.
The aircraft has two MPCD's (Multi-purpose colour displays) - The left hand screen providing an INS (Inertial Navigation System) and the right providing forward looking infra-red and other visual aids. All lights and buttons light up green so it doesn't ruin the pilot's night vision.
An inertial navigation system is a navigation aid that uses a computer, motion sensors and rotation sensors (gyroscopes) to continuously calculate via dead reckoning the position, direction, and speed of a moving object without the need for external references. This is more reliable than GPS (Global positioning system) as that could be switched off or lose signal. The moving map display shows all avoids, Air Traffic zones, airways and airfields aswell as the terrain and contours. On top of that the mission route and waypoints are also displayed and the system allows new waypoints to be created at the press of a button to come back to later.
Apart from inputting frequencies, the keyboard of buttons inbetween the two screens also input co-ordinates into the mission computer. If a Harrier was giving close air support, a ground unit could call up the pilot on a tactical frequency and give him lat/long coordinates of a target which he would then input into the computer. The pilot would then get into a good position to make his run on to the target. The HUD (Head up display) would show a line/path up to the target.
Guided missiles use their own internal systems to lock onto and steer towards the target. When the target is set, the usual box will surround the target on the HUD. Once the target is within the maximum range of the weapon, this box changes into a diamond.
Laser guided bombs are similar to the above apart from they follow a laser on to the target from the aircraft or can even be from another aircraft or ground unit. The target indicator box still comes up come up as before. Once in range, the box will change to an oval.
Uncontrolled 'retarded' bombs are less simple. The bombs must be dropped at precisely the right moment if it's to hit the target. The computer calculates and gives all the information on the HUD. The HUD would give the pilot a 'bomb-sight' symbol and when the target enters the bomb-sight the pilot would drop the weapon.
Whilst being shown around the cockpit of the Harrier, the Lieutenant pointed out a red button slightly to the back and bottom of the stick.
Whilst in the air the rudder puddles control the yaw of the aircraft. When the aircraft lands the pilot must press this button to engage the nose wheel to the pedals so that the Harrier could turn on the ground. The Lieutenant told me that when the button is pressed it is very easy to be caught out if the rudders aren't dead straight otherwise there could be a very violent swerve to one side!
The Harrier is most famous for it's vertical flight using it's nozzles. To direct the nozzles there is a leaver beside the throttle that alters the angle of the nozzles. This has caught one or two pilots out in the past when they have moved the nozzle leaver instead of the throttle. Most noteably, this happened at Lowestoft Airshow in 2002 which led to the pilot ejecting and the aircraft plummeting into the sea.
The Harrier was one of the last successful British military aircraft built and as a result the aircraft was extremely popular.
The Dominie, Nimrod and Jetstream did not receive a big send off unlike the Harrier which was a testament to it's popularity.
To celebrate the aircraft's brilliant service, four retirement schemes were rolled out from each squadron and an overall Harrier retirement scheme.
ZG506 - Harrier Retirement Scheme
This aircraft was painted in a 'retro' gloss camouflage scheme to replicate the scheme the first Harrier GR.1 wore at Cambridge back in 1969. This was the last Harrier to land on the farewell day, ending the Harrier's service career with a final bow to the press.
ZG477 - 1 Squadron Disbandment Scheme
1 Squadron's special tail celebrates the fact that it was the first squadron to operate the Harrier back in 1969. The squadron remained operational until the end of the Harrier. The Squadron bade is a winged '1' numeral.
ZG858 - 4 Squadron Disbandment Scheme
4 Squadron's special tail is it's Black, yellow and red 'thunder' badge with "1970-2010" written on it.
In 1970 4 Squadron took delivery of it's first Harriers in Germany. 4 sqn supplied the final display routine during the 2010 season with ZG858 being the display aircraft.
ZD351 - 800 Naval Air Squadron Disbandment Scheme
800 NAS's retirement scheme is in my opinion the most interesting scheme. The tail says "1980 - 2010" but the Royal Navy wanted the tail to have the start year and disbandment year of the squadron which was 1933 but word has it (From the Royal Navy side) that the Air Force didn't want them to have an earlier date on their tail and was told to put the date they received the Harrier, 1980. Also when the tail was created, it was delivered to 800 NAS with spelling mistakes in the names it saw action down the side of the rudder. This was sent back and corrected with tape laid over the errors.
Before they knew it, it was all over. The Harrier pilot that very kindly showed me round RAF Cottesmore flew to Yeovilton not realising it was his final flight. A few weeks later, he was watching his colleagues take off to form a 16-ship.
The Harriers are now being stored after receiving full maintenance, being taped up and removing the one-piece wing from the aircraft. They are likely to be either sold on or scrapped though it is thought a select few may go to museums.