The Birth of the Harrier – A Diamond Anniversary

P1127 – First hover

On 21 October 1960 at Hawker’s Dunsfold airfield in a small, strange looking aircraft with an unusual design of undercarriage squatted on a metal grid covering a deep pit in the concrete hard standing. The pilot was in the cockpit and several ground observers, wearing ear defender headsets which were wired to the aircraft, surrounded this peculiar machine. It came to life as its BE53 engine was started and with a unique whine, increased to ground idle for few minutes before its four exhaust nozzles were rotated down and full power was selected. The noise level rose to a high decibel roar and the machine staggered unsteadily clear of the ground. This was the first attempt to achieve a vertical take-off and brief hover of the unique P1127 which, for this pioneering “flight”, was stripped of all surplus weight and tethered at a maximum altitude of only about four feet to ensure a level of safety. The men behind this successful demonstration were Sir , the Hawker chief designer and Sir the Bristol chief engineer. As work progressed, letters held in the Trust archives confirm that the initial formal relationship between the two principals relaxed to the level of “Syd and Stan” and both men had confidence in their engineers. The detailed project work was delegated to at Kingston for the airframe and to in Bristol for the propulsion system which had been conceived specifically for the Hawker project. Lewis’ unique design was based on an adapted turbofan but with the cold bypass flow diverted through a pair of rotatable nozzles and the remaining air entering the conventional combustion system before being exhausted through a separate pair of nozzles. Hooper, Lewis and their engineers worked very closely to ensure the subsequent success of the project where the challenge to both design teams was to ensure that with the nozzles pointed down, the gross vectored thrust coincided with the centre of gravity of the aircraft. With high pressure puffer ducts at the airframe extremities, fed from the engine’s high pressure compressor, the aircraft was balanced in the hover. Prior to the first flight, Hooker is claimed to have asked of Camm "I suppose you are going to do some conventional flying first Sydney?" and Camm replied "What for?" Hooker said "Well you know, just to make sure it’s a nice aeroplane, and that everything is under control". Camm is said to have replied, "Hawker aeroplanes are always beautiful, nothing wrong with a Hawker aeroplane, not going to bother with that; vertical first time” and so it proved.

Within a month the tethers had been removed and the P1127 finally had hovered in free air, clear of the high energy jet efflux in ground effect which had affected the handling during earlier attempts. By March the following year it had flown as a conventional aircraft and in September only eleven months after its first tentative hover the P1127 had achieved a vertical take-off and transition to conventional flight before decelerating to the hover for a vertical landing. This was the gestation of the project which became the iconic Harrier, the world’s first vertical and short take-off and landing (VSTOL) combat aircraft, powered by the remarkable pioneering BE53 engine, the Pegasus. The busy flight test and development programme led to minor systems improvements and changes to the airframe design while the engine was developed to produce more thrust with better handling both in hovering and conventional flight so that three years after that first tentative hover, the P1127 had dived at supersonic speeds and had landed on an while underway at sea.

P1127 at sea

So, what were the attractions of jet VSTOL combat aircraft? The concept enabled fighters to operate from austere strips, away from vulnerable airfields and, at sea, to fly from smaller ships without the need for extensive and cumbersome catapult and cable arrester gear. The P1127 was not the first jet powered machine to hover and a number of research designs, which were neither promising nor practical, had flown in the USA. In Britain in the early 1950s, Rolls-Royce pioneered the concept of jet lift with its thrust measuring rig (TMR) which had two Nenes mounted back to back with their exhausts deflected downwards and constrained in a gantry. Suitably restrained it “flew” in 1953 with its first untethered hover taking place the following year. Known colloquially as the Flying Bedstead, it performed vertical take offs and landings and manoeuvred in the hover although conventional flight was impossible. The ungainly Short SC1, which carried five RB108 engines, four for lift and one for propulsion, benefitted from TMR research data and had achieved a vertical take-off, transition to conventional flight and return to a vertical landing many months before the first hover of the P1127. However carrying a battery of lift engines used solely for take-off and landing was judged to be complicated and inefficient hence the SC1 was retained solely as a research vehicle. Other countries had investigated jet VSTOL but none had resulted in a successful practical design other than the Yak38 Forger which served with the Soviet Navy from 1976 to 1991.

Initially, development of the first two P1127s was financed privately by Hawker until the government recognised the potential and a few months before that first hover, some funding was provided for a further four development aircraft, but solely for research. At the same time Ministry of Defence aspirations were still constrained by the short sighted policies following the infamous 1957 Defence White Paper which, inter alia, had cancelled all future manned fighters. In the early 1960s there was much scepticism in both the and about the perceived benefits of VSTOL as there was a common, but inaccurate, belief that aircraft designs with such a capability would have performance limitations. By early 1962 however, Hawker had demonstrated the validity of the P1127 design, and despite the modest British enthusiasm, NATO had become attracted to a ground with a VSTOL capability. Military support developed and there was an almost grudging agreement by the government that Britain should be involved in such a requirement, thus reversing its previous short-sighted policy that there would be no more manned combat aircraft. On paper, Hawker’s P1127 concept was a suitable basis for the development of a supersonic multi role fighter to meet a NATO Basic Military Requirement (NBMR3), with the aim of equipping the RAF and RN with a multi-role common airframe, designated the P1154.

To confirm the feasibility of VSTOL combat aircraft, an interim project based on an austere development of the P1127 aircraft, was submitted in early 1962 to fulfil the requirement for an operational trials unit. This was planned to be a small squadron, part of the RAF Central Fighter Establishment at West Raynham in Norfolk. As a result of overt interest from lobbies within the United States and West Germany, the British government approached these two nations with an offer to collaborate on the project and to seek contributions towards its cost. Following acceptance by all three nations in May 1962, Hawker received a formal contract to procure materials for the construction of nine Kestrel aircraft, the improved version of the P1127. The project was authorised and funded as a tri-national enterprise involving Britain, the USA and Germany with the aim of ascertaining the operational viability of deployed VSTOL operations.

In October 1964, the Tri-partite Evaluation Squadron (TES) was formed at RAF West Raynham, staffed by a diverse mix of experienced military pilots and ground crews from Britain, the United States and West Germany, commanded by Wing Commander David Scrimgeour (RAF) who had been my Hunter squadron commander in 1960. Before flying the Kestrel, each TES pilot received a week's ground training on the Pegasus engine at Bristol and a week's ground instruction at Dunsfold including a three-hour flight conversion briefing given by . The international ground crew were given a similar pattern of training in the unique features of the engineering support for the P1127, particularly the Pegasus turbofan with its special vectoring nozzles.

Kestrel FGA1

The purpose of the squadron was to evaluate the suitability of VSTOL aircraft for deployed operations, compare different handling and methods for take-off and landing, develop normal flight operating procedures, perform instrument flight assessments, conduct night flight operations, and explore jet-borne manoeuvring throughout the Kestrel's flight envelope. The trial lasted for six months and confirmed the viability of VSTOL or, more accurately, Short Take Off and Vertical Landing (STOVL) operations from dispersed sites. Interestingly, neither the US Marine Corps nor the Royal Navy were represented and neither were trials conducted at sea although the P1127 had flown previously from HMS ARK ROYAL to prove the ease of operation from ships at sea.

Just as the tripartite trial was underway in 1965, the new government’s defence review cancelled the P1154 project and ordered instead McDonnell F-4 Phantoms, modified with Spey . Also sixty of a much improved version of the Kestrel, designated the P1127 (RAF), were ordered to retain design expertise at the big Hawker factory at Kingston and to retain the STOVL features which the Tripartite trial had proved to be a highly desirable capability. Although resembling the Kestrel visually the much modified aircraft, now confirmed as the Harrier, was slightly heavier, had a bigger wing and was equipped fully as a combat aircraft with a self- contained navigation and attack system, podded guns and five pylons for carrying external stores such as weapons and fuel. So the Harrier GR1 entered RAF service in 1969 as a ground attack fighter with the ability to deploy to forward operating bases away from main airfields.

Harrier GR3

The various concepts of operation reduced vulnerability and gave ground forces a quicker response to requests for air support. Squadrons were exercised regularly, deploying routinely within NATO, and Harriers remained an impressive contribution to the RAF front line during the , serving throughout Europe and in before the upgraded GR3 acquitted itself in combat operations during the Falklands campaign. Six aircraft flew to where together with eight Sea Harrier reinforcements, they were shipped as deck cargo on board the container ship Atlantic Conveyor for transit to the South Atlantic. On arrival in the operational theatre they took off vertically and landed on the adjacent HMS HERMES to be available for tasking primarily in the familiar and well exercised ground attack role.

Harriers and Sea Harriers on board Atlantic Conveyor

On board HMS Hermes Off Ascension

Four aircraft were lost, three to ground fire and one in an accident, but four more GR3s flew non-stop with air refuelling from Ascension to HERMES, a nine hour sortie, which demonstrated the remarkable flexibility of the Harrier and the courage of the pilots.

My first flight in a Harrier was from Dunsfold in 1971 when I managed to scrounge a trip in the rear seat of a T2 with . This whetted my appetite and as I was due to return to the cockpit after a ground tour I applied for a posting to the Harrier Force. Later that year I was delighted to know that my posting was confirmed and, via the customary refresher training on the Jet Provost and Hunter, I underwent operational conversion at Wittering to begin an unbroken eleven years association with the Harrier, in and out of the cockpit. It was a delight to fly and its sparkling performance in both STOVL and conventional flight proved the flexibility of Kingston’s design and Bristol’s rugged Pegasus engine.

Subsequently during my MoD tour in the mid 1970s we recognised that, while the Harrier’s capability was unique, it lacked modern avionics for more accurate navigation and weapons delivery and its overall performance in terms of manoeuvrability, range and payload was deficient. Having flown the GR3 for three years I was well aware of the shortcomings and had considered options for improvements in these criteria. So I began to explore the possibility with the Kingston project team of designing a new wing for the Harrier GR3 which could improve its payload and performance and extend its range. Because the wing assembly was removed as a single item for routine engine changes my proposal was that a larger wing could be fitted as a replacement and that this modification could provide such improvements. Wing loading could be reduced, manoeuvrability enhanced and the greater area would allow more fuel to be carried internally and provide the space for additional underwing pylons. It seemed to be a simple proposal although I acknowledged that matters would be a challenge to the designers nor would the engineering be straightforward! The late Dr and his Kingston team were supportive and by early 1977 I had drafted the first air staff papers for circulation within the MoD to justify a feasibility study for a much improved GR3, which we termed the GR5, the "Big Wing" Harrier.

From top to bottom – “Big wing Harrier” options Harrier GR3, H-S “GR5”, Joint H-S McDonnell GR5

Coincidentally the US Marine Corps, which had bought 120 Harriers between 1971 and 1974 carrying the US designation AV-8A, were pursuing similar options to enhance the performance of their aircraft. They were enthused by its unique operational advantages and were determined to retain its STOVL features in a replacement aircraft rather than a modification to the existing type. Both services wanted greater range, heavier payload, more thrust and digital avionics. The only difference in requirements was that we wanted better manoeuvrability at higher speed whereas the Marines sought improved VSTOL handling. By 1980 the financial priorities in the MoD had changed and a budget was made available for a Harrier replacement so the attractions of a shared programme were studied looking at the operational capability, the operating costs, the potential benefits to British industry and of course the acquisition budget. The decision was made that the second generation of the aircraft should become a collaborative programme between the USA and Britain. In the 1980s a much more capable aircraft, the AV-8B, known as the Harrier GR5/7 in the UK, entered RAF service and became the ground attack aircraft of choice in supporting the Army. Subsequent operations over the , Iraq and Afghanistan proved its worth and continued to serve widely until its premature disbandment in 2010.

Harrier GR7

In the years leading up to the decommissioning of the ’s carriers and the loss of its fixed wing aircraft, the Royal Navy had finally recognised the attractions of STOVL and the HMS INVINCIBLE class of ship became a small aircraft carrier; for bizarre political reasons known as a “through deck cruiser”. The requirement was to provide air defence for the North Atlantic convoys which were vital reinforcements during the Cold War. A development of the Harrier GR3 was the basis for a suitable aircraft and by 1978 the prototype Sea Harrier, known colloquially as the SHAR, had made its first flight.

Sea Harrier FRS1

The aircraft was modified with a raised cockpit and a "bubble" canopy to provide greater external look out. The forward fuselage was extended to accommodate the Ferranti Blue Fox and some parts were changed to protect against the corrosive marine environment by using salt resistant alloys or adding suitable coatings to vulnerable metal items. Based ashore at RNAS Yeovilton the multi role SHAR became operational on board HMS INVINCIBLE and the elderly, but much modified HMS HERMES just in time to take essential roles in the Falklands campaign. It served the Royal Navy very successfully over its 29 years of service with a formidable reputation as a fighter in the South Atlantic where, mainly using the Sidewinder missile, it shot down 23 Argentine aircraft with no losses although two SHARs were lost due to ground fire and four in accidents.

Lessons from the Falklands campaign led to a major modification programme for the SHAR FRS1 to enhance its operational performance. The monopulse Blue Fox radar was replaced by the Blue Vixen doppler system which, together with the Advanced Medium Range Air to Air Missile, gave the SHAR FA2 a much improved air defence capability.

Sea Harrier FA2

SHARs were in action in the Balkans throughout the 1990s primarily as air defence assets but were used also in the ground attack role. However in 2002, the MoD announced that all SHARs would be withdrawn from service by April 2006, and that a combined RAF/RN Joint Force Harrier (JFH) would use RAF Harrier GR7/9s by 2007. Between 2004 and 2006 the three SHAR squadrons at RNAS Yeovilton were disbanded and despite its undoubted operational success the government’s puzzling decision to remove the recently modernised SHAR was a blow to the Royal Navy’s STOVL lobby.

The JFH front line assets were based at RAF Cottesmore but the conversion unit remained at RAF Wittering, the original home of the Harrier. All three front line squadrons, two RAF and one Royal Navy, were deployed continuously on operations in Afghanistan until 2009 and exercised at sea aboard the RN aircraft carrier HMS ARK ROYAL. However the new government’s 2010 Strategic Defence and Security Review included an announcement that the entire Harrier Force was to be withdrawn as an economy measure and that HMS ARK ROYAL was to be decommissioned. These measures, apparently, were to save money for the purchase of the two HMS QUEEN ELIZABETH-class aircraft carriers and it is ironic that the new ships were commissioned before they had the ability to embark the Harrier’s replacement, the STOVL F-35B.

Final Flypast December 2010

Four Joint Force Harriers made their final flights from HMS ARK ROYAL at sea in November 2010 and the following month, from RAF Cottesmore, with a ceremonial flypast of sixteen aircraft before most of the remaining British Harriers were sold to the United States to become spares for the US Marine Corps fleet, an ignominious end for this pioneering aircraft’s 41 years of operational service in the Royal Air Force and some 29 years with the Royal Navy.

Jock Heron October 2020 Vice President Rolls-Royce Heritage Trust Bristol Branch