Hawker Aircraft Ltd took over the lease of Dunsfold Aerodrome in 1950 (41). Hawker Aircraft Ltd went through many new names over the next half century, and as BAe Systems ceased activity at the aerodrome in 2000. The Aerodrome was sold to the Rutland Group in 2002. (42)
By the early 1950s, Hawker’s were developing jets for which the short, grass landing strips then available to them, were not sufficient. They needed long, hard-surfaced runways, which was what Dunsfold could provide. (43)
On taking over the Aerodrome, Hawker Aircraft Ltd “built up a final assembly and experimental test facility in the two T-2 hangars as a basis for expansion (44). Dunsfold is associated with several types of aircraft including Hunters and Hawks, but the Aerodrome is best associated with the Harrier. We now look at each of these in turn.
The Hunter
The Hunter could be regarded as the beginning of Dunsfold Aerodrome’s role at the cutting edge of military jet aircraft development. Hunters were early jet fighter aircraft: the first flew in 1951. (45)
In 1953, Dunsfold was the base for important speed tests. In January of that year the speed of sound was achieved and on 7 September a Hunter, piloted by Squadron Leader Neville Duke, broke the world air speed record off Littlehampton achieving 727.6 m.p.h. Later the same month, the 100km world record — 709.2 m.p.h — was established from Dunsfold by Duke. (46) The plane is on display at Tangmere Military Aviation Museum. (47)
The record-breaking Hunter .
As a result, complaints about the noise started; test pilot Neville Duke reported “At Dunsfold we hear tales of people being flung off bicycles by the bangs—but I don’t believe them”. (49) By 1954, the noise issue had become serious. A local farmer, Col. du Boulay, issued a writ, but was persuaded to withdraw it by assurance that the nuisance would be abated by technical means. However, the Ministry of Civil Aviation immediately took action to prevent any future writs so as to protect the production of military aircraft. (50)
Hunters were put into service by the RAF in 1954 and were used until the 1990s. They were employed in the 1956 Suez Crisis and numerous other conflicts. (51) As well as being used by the RAF and the Royal Navy, they saw service in Abu Dhabi, Belgium, Chile, Denmark, India, Iraq, Jordan, Kenya, Kuwait, Lebanon, Netherlands, Oman, Peru, Qatar, Rhodesia, Saudi Arabia, Singapore, Somalia, Sweden and Switzerland. (52) In fact they were in military use somewhere in the world until 2014. (53)
The Hunter continued in production, or refurbishment, until 1980 by which time almost 2,000 had been produced. It is reported that “the Hunter cost £100,000 in 1956, which is not far off £450,000 in 1974 money” (54) ; and about £16,000,000 when estimated at 2011 prices. (55) That clearly represents a great deal of money!
The Harrier: the “Jump Jet”
“Jump jets” are, technically speaking, vertical (or short) take-off and landing (VTOL or V/STOL) aircraft that can also be used on short runways. They can operate from clearings in forests and small aircraft carriers. The Harrier is unique in that it is the only aircraft using vectored thrust so that it can take off, fly and land either vertically or conventionally. BAe proudly says “The Harrier was the only true STOL (short take-off and landing) aircraft in the world.” (56)
The Kestrel flying from Dunsfold
In October 1960, the Hawker Siddeley Group’s P.1127, “the world’s first operational vertical take-off strike aircraft, made its first tethered flight at Dunsfold Aerodrome” which led to the Daily Express running the front-page headline “The Jumping Jet” (57). The plane is now on display at the Science Museum in London. (58)
The first P.1127 in “free hovering flight” at Dunsfold Aerodrome (59)
The P.1127 evolved into the Kestrel and then the Harrier. (60) In 1967, Flight International announced “HARRIER World’s first fixed-wing V/STOL weapons system”, with a nine-page article describing its history and novelty. (61) By 1969, the RAF was using Harriers. (62) The potential for use at sea was recognised from the start with the Hawker Siddeley P.1127 landing on HMS Ark Royal in 1963. (63) However, it was not until 1978 that the prototype “Navalised-Harrier” took to the air over Dunsfold. The first Sea Harrier joined the Royal Navy in 1980. (64)
May 1969 Trans-Atlantic Air Race
Military impact
The Falklands War started on 2 April 1982 when Argentina invaded the Falkland Islands, a British Overseas Territory some 300 miles off its east coast and some 8,000 miles from the UK. The British Government dispatched a Task Force on 5 April. The resulting conflict ended with the Argentine surrender on 14 June 1982, returning the islands to British control.
Dunsfold Aerodrome immediately went on to a war-footing. The three Harriers based at Dunsfold for trails were commandeered and one was to be seen on HMS Hermes ski-jump as it sailed from Portsmouth. (65) Dunsfold went on to double-shift working to modify Harriers and Sea Harriers for air combat and ground attack roles in the South Atlantic and played a crucial role in ensuring that the Royal Navy was in a position to send a second Sea Harrier- equipped carrier to the Falklands, though the conflict ended before this was necessary. (66) Dunsfold test pilot Taylor Scott volunteered to return to the Royal Navy to help form and train an additional Sea Harrier squadron, 809. (67) It is reported that 42 Harriers and Sea Harriers were deployed. (68) BAe comments “The usage in the Falklands was probably the most high profile and important success recorded” as “it was the only fixed-wing fighter available to protect the British Task Force.”(69) Sea Harriers shot down at least 28 Argentinian aircraft, without loss in air-to-air combat (although there were losses on the ground). The Harrier was vital in winning this conflict.(70) When reporter Brian Hanrahan worked around the reporting restrictions by saying, “I counted them all out, and I counted them all back”, he was counting Harriers. (71) As a result of this success, the British Government immediately ordered more Sea Harriers.(72)
Harriers were also important in the 1990-91 Gulf War and in NATO’s action in Kosovo in 1999 and elsewhere.(73)
Economic impact
The Harrier – technically the AV-8A – made export history when 112 were sold to the US Marine Corps (USMC) in 1971. (This was the first time the US had bought a foreign built military aircraft since the First World War.) They had to be freighted to the US, which meant that large cargo carriers had to land at Dunsfold. (74)
The Harrier II, a follow-on to the AV-8A, was designed by McDonnell-Douglas in St Louis USA with Hawker Siddeley Aviation/BAe, and was built on a roughly 50-50 work share basis by the two companies. Dunsfold built the centre and rear fuselages and reaction control systems for all the aircraft delivered, and McDonald-Douglas built all the wings and front fuselages. These items were shipped across the Atlantic for final assembly as the RAF Harrier GR5/7 at Dunsfold and as the AV-8B for the USMC at St Louis. (75)
Manufacturing of the Sea Harrier ceased in 1998 with the last aircraft retiring from the Royal Navy in 2006 and from the RAF in 2011 (76).The Sea Harrier was in service with the Indian Navy until 2016 and the AV-8B remains in service in the USMC; and in the Spanish and Italian navies in 2017 (77).
AV8B
It is claimed that 278 Hawker Siddeley Harriers (78) were produced, plus 111 Sea Harriers79, 347 AV-8As80, and 143 Harrier IIs (81). That comes to 879. Costs are difficult to come by but it is suggested it could be of the order of $24-30 million (£19,000,000 – 24,000,000) each. (82)
Summary
In 1985, Ashworth reported that, “Starting with the P.1127’s first tentative hover on October 21 1960 up to the current Sea Harrier, all British development, assembly and testing of this family of vertical take-off aircraft has been at Dunsfold”. (83) However, the technical legacy of the Harrier lives on today in the F-35 Lightning II STOVL variant. (84) Delve wrote: “This fantastic British aircraft is enough for Dunsfold to have a place in aviation history”. (85)
The Hawk
The Hawk started life as the HS 1182, “intended to replace the Gnat, Jet Provost and Hunter as the RAF’s jet trainer”. It is also used as a low-cost combat aircraft. In 1971, the cost was put at £450,000 each.86
In 1972, the RAF “ordered 176 to be assembled and test flown from Dunsfold”. 87 The first Hawk flew from Dunsfold Aerodrome in 1974, piloted by Duncan Simpson.88
Hawk 200 in Engine Running Pen (1980s) (courtesy Brooklands Museum archive)
An important derivative of the Hawk was the T-45 Goshawk, produced jointly with McDonald Douglas, starting in 1981. The T-45 Goshawk was designed by BAe and McDonald Douglas in California. British designed components were shipped across the Atlantic for final assembly for the US Navy. When production ceased in 2009, 221 had been delivered. It is still in use as a carrier-capable advanced trainer. (89)
Most famously, these are the planes used by the Red Arrows. From their inauguration in 1964, the Red Arrows had flown Gnats.90 But the last Gnat to go to the RAF was delivered from Dunsfold in 1965. In the winter of 1979/80, the Red Arrows graduated to Hawks. (91)
Some 1,000 Hawks have been produced and they have been delivered to 18 countries. 93 They are still in production. (94) It is reported that they cost £18,000,000 each in 2003. (95)
39 See https://en.wikipedia.org/wiki/Cold_War 40 McCue, 1991: p213.
41 Ashworth, 1985: p85.
42 Dunsfold Park, 2017.
Photo courtesy of BAE Systems via Brooklands Museum
The main runway has the unique Vertical Take Off Grids, known as VTO Grids or Hover Grids – used for the tethering of jump jets such as the Harrier whilst hovering. These are located on aprons that adjacent the main runway and are within the Operational Readiness Platform [ORP]. Beneath these gratings is a large void chamber to take the hot air, condensation and gases from the downdraft of the jet engines of the aircraft. Within the eastern Engine Testing Pen there is a similar arrangement that is a unique feature to Dunsfold.
The Hawker P.1127 and the Hawker Siddeley Kestrel FGA.1 were the experimental and development aircraft that led to the Hawker Siddeley Harrier, the first vertical and/or short take-off and landing (V/STOL) jet fighter-bomber. Kestrel development began in 1957, taking advantage of the Bristol Engine Company’s choice to invest in the creation of the Pegasus vectored-thrust engine. Testing began in July 1960 and by the end of the year the aircraft had achieved both vertical take-off and horizontal flight. The test program also explored the possibility of use upon aircraft carriers, landing on HMS Ark Royal in 1963. The first three aircraft crashed during testing, one at the 1963 Paris Air Show.
Improvements to future development aircraft, such as swept wings and more powerful Pegasus engines, led to the development of the Kestrel. The Kestrel was evaluated by the Tri-partite Evaluation Squadron, made up of military pilots from Britain, the United States, and West Germany. Later flights were conducted by the U.S. military and NASA.
Testing at Dunsfold in the engine detuning pens
Related work on a supersonic aircraft, the Hawker Siddeley P.1154, was cancelled in 1965. As a result, the P.1127 (RAF), a variant more closely based on the Kestrel, was ordered into production that year, and named Harrier – the name originally intended for the P.1154 – in 1967. The Harrier served with the UK and several nations, often as a carrier-based aircraft.
Following the end of the Korean War, a number of aircraft companies in both Europe and America separately decided to investigate the prospective of vertical take-off and landing (VTOL) aircraft, which would eliminate the requirement for vulnerable runways by taking off and landing vertically as opposed to the conventional horizontal approach. In addition to military applications, the prospect of applying such technology to commercial airliners was also viewed with considerable interest by the mid 1950s, thus the value of developing viable vertical take-off systems was judged to be substantial. However, even during this era, few companies had envisioned that a VTOL aircraft would also be realistically compatible with the characteristics of high performance military aircraft.
In 1957, jet engine engineer Stanley Hooker of the Bristol Engine Company informed aeronautics engineer Sydney Camm of Hawker Aircraft that Bristol had been working a project that combined major elements of their Olympus and Orpheus jet engines to produce a directable fan jet. The projected fan jet harnessed rotatable cold jets which were positioned on either side of the compressor along with a ‘hot’ jet which was directed via a conventional central tailpipe. The original concept upon which the engine, which had been named Pegasus, was based came from Michel Wibault, a French aviation consultant. Several adaptions and enhancements were made by Bristol to reduce size and weight over Wibault’s original concept.
Around the same point as Hooker’s approach, Hawker had been working upon the development of a replacement fighter aircraft for the Hawker Hunter, designated as the P.1121. However, the P.1121 was cancelled shortly after the publishing of the 1957 Defence White Paper, which had advocated a policy shift away from manned aircraft and towards missiles.In light of this cancellation, Hawker found itself with the available resources to commit to a new project, and thus decided to study the use of the projected Pegasus engine as a basis for a new military aeroplane that would be able to conform with an active NATO specification that sought a new Light Tactical Support Fighter to replace the Fiat G.91, particular attention was paid to meeting the specification’s performance and load requirements.
According to Air Chief Marshal Sir Patrick Hine, Hawker’s interest may have also been stimulated by the presence of Air Staff Requirement 345, which sought a V/STOL ground attack fighter for the Royal Air Force (RAF).[9] Aviation author Francis K. Mason expressed a contrary view, stating that Hawker’s decision to proceed was independent of British government initiatives, and that the P.1127 project was primarily based upon the NATO requirement instead. Hawker had a keen ally in its development in the form of Bristol, but by that point the latter was experiencing financial difficulties, and the lack of foreseeable commercial applications for the Pegasus engine in particular, coupled with refusals from HM Treasury, mean that development would have to be financed by NATO institutions instead. The close cooperation between Hawker and Bristol was viewed by project engineer Gordon Lewis as a key factors which had enabled the P.1127’s development to proceed in spite of technical obstacles and political setbacks.
Origins
Senior project engineer Ralph Hooper at Hawker promptly set about establishing an initial layout for a theoretical aircraft to take advantage of the Pegasus engine, using data provided by Bristol. This proposed aircraft soon received the internal designation P.1127. In July 1957, a modification made to the design was the incorporation of a bifurcated tailpipe, similar to the Hawker Sea Hawk, which was equipped with rotatable nozzles for the hot exhaust, similar those already used for the cold exhaust. The switch from a single tailpipe meant that the initial tailwheel undercarriage could also be discarded in favour a conventional nose wheel-led undercarriage. The design process extended throughout 1958, being financed entirely by Hawker, while approaches were made to NATO headquarters to better establish the tactical requirements sought, particularly between the conflicting demands for a lightly armed supersonic fighter and a simpler multipurpose subsonic one.
The development process had involved extensive use of physical models; for one series of blowing trials, mixtures of focused hot and cold air were directed onto ground platforms to simulate the ground effect upon take-off. This work was considered to be critical to the project as there was very little knowledge of the adverse effects which could influence the aircraft during the vertical takeoff process; as there was no airflow over the ailerons, tailplane, and rudder while the aircraft was held in a stationary hover, wingtip control jets were experimented with as an alternative reaction control approach. These research included the development of an all-new control response simulator which linked a series of simple flying controls to a computer. By the end of 1958, barely eighteen months after the start of the project, all the main features of the P.1127 were developed with one exception, that being the reaction control system, the development of which was completed by April 1959.
Throughout the development, Camm heavily emphasised the importance of the design’s simplicity, observing that “Sophistication means complication, then in turn escalation, cancellation, and finally ruination”.[12] In 1958, the design centered around a single Pegasus engine capable of generating 13,000 lb of thrust; when fully equipped, the aircraft was to weight slightly less than the maximum thrust, thereby allowing vertical takeoffs to be performed under all nominal conditions.[12] During late 1958, the rapid progress of the P.1127 project had been noticed by technical advisors at NATO, who began promoting the acceleration of the aircraft’s development and that member nations should skip over the next generation of support fighters in favour of the emergent P.1127 instead. In Britain, support for the program was also growing within the British Air Staff, from January 1959 onwards, rumours of a pair of P.1127 prototypes being ordered by the Ministry of Supply alongside those of a Air Ministry specification being drafted around the project frequently echoed.
As the P.1127 had been developed at a time of deep UK defense cuts, Hawker had to seek commercial funding, and significant engine development funding came from the U.S.Research assistance was also provided by U.S.; including a series of wind tunnel tests conducted by NASA’s Langley Research Center using sub-scale models, which demonstrated acceptable flight characteristics. Hawker test pilot Hugh Merewether went to the U.S. at NASA’s request to fly the Bell X-14. In March 1959, the company’s board of directors (Hawker Siddeley then) decided to privately fund two P.1127 prototypes.
In February 1959, Hawker had completed practically all of the design work and thus passed the entirety of its manufacturing design work to the company’s Experimental Design Office at Kingston, London.[12] In April 1959, the Ministry of Supply formally issued a contract for the completion of a pair of P.1127 prototypes. However, there were critics amongst the Air Staff of the project, typically disliking the P.1127 for its subsonic speeds, favouring supersonic-capable aircraft instead; Mason attributes this as having caused considerable delay in the issuing of a contract to Hawker. On 23 July 1959, Hawker authorised the application of maximum effort to complete the development of the P.1127.
On 15 July 1960, the first “P.1127 Prototype V/STOL Strike Aircraft”, serial XP831, was delivered to RAF Dunsfold, Surrey, to commence static engine testing. On 31 August 1960, the Pegasus engine was ran for the first time while inside the airframe. Some of the tests were performed from a purpose-built platform at the aerodrome, which functioned to deflect the hot exhaust gases away from the aircraft during early hovering trials while more powerful versions of the engine were developed.[20] On 13 October 1960, the first Pegasus flight engine, capable of generating 11,300 lb of thrust, was delivered to Dunsfold.
On 21 October 1960, the initial tethered flight, performed by XP831, was conducted at Dunsfold; at this stage of development, this feat had required the airframe to have been stripped of all extraneous weight and restrictions on the engine meant it could not be run for more than 2.5 minutes at a time. Several tethered flights took place, partially so that the test pilots could familiarise themselves with the hovering controls; on 4 November, the first tethered flight without use of the auto-stabiliser system was accomplished. In mid-November, conventional taxying trials were performed at speeds of up to 70 knots.
On 19 November 1960, the first un-tethered free-flight hover of XP831 was achieved; a week later, the first publicity photos of the P.1127 were released.[20] 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 the aeroplane is a nice aeroplane, and everything under control.” Camm replied, “Oh, Hawker aeroplanes are always beautiful, nothing wrong with a Hawker aeroplane, not going to bother with that. Vertical first time”.[21]
On 13 February 1961, XP831 performed its first conventional flight, flown by Bill Bedford and lasting for 22 minutes.[22] Soon after this, XP831 was refitted with a new model of the Pegasus engine, capable of generating 12,000 lb of thrust, prior to embarking on new hovering trials in May 1961. In June, XP831 attained another milestone in the program when it performed the first transition from vertical hover to horizontal flight, initially flying the length of Dunsford’s runway at a height of 50 meters.
On 7 July 1961, the second prototype, XP836, performed its first take off conventionally. Continuing tests of the two prototypes proceeded to close the gap between vertical take off and flight, a feat which was achieved on 8 September 1961.] During September, the feat was repeated multiple times by both prototypes, transitioning from vertical to horizontal flight and vice versa, including instances in which the auto-stabiliser was intentionally disabled.
During the flight test program, the issuing of NATO Basic Military Requirement 3 (NBMR-3) did not prove to be the opportunity as envisioned by Hawker, as NBMR-3 sought performance characteristics of which the P.1127 was not only unable to meet, but unlikely to be developed to meet in its current form either. As such, in 1961, there was little military interest in the P.1127 program, although, in January 1961, Hawker was requested to provide a quote for the costs involved in a potential 100 production standard P.1127 aircraft. Meanwhile, Hawker believed that the continuing development of the P.1127 would serve a successful demonstration, acting to dissuade potential customers from pursuing competing ‘paper’ VTOL aircraft projects.
On 2 November 1960, the Ministry of Supply issued a contract for a further four prototypes to be produced, which were intended to develop the aircraft further towards being a realistic combat design, such as the refinement of the wing, engine improvements, and of accompanying operational equipment. Throughout this period, improved models of the Pegasus engine were rapidly developed, such as the Pegasus 3 being capable of 15,000 lbf (67 kN) of thrust. Apart from the improved powerplants, the first four P.1127 prototypes were quite similar; the fifth prototype, XP980, introduced the taller fin and tailplane anhedral which were later used on the production Harrier. The fourth machine was partially used to provide Hawker production test pilots with type familiarisation.[25] The first carrier vertical landing was performed by the first prototype on HMS Ark Royal in 1963. The last P.1127, XP984, introduced the swept wing.[25] It was eventually fitted with the 15,000 lbf (66.7 kN) Pegasus 5 and functioned as the prototype Kestrel.
The first three P.1127s crashed, the second and third occurring during development. In 1963, the first prototype, XP831, publicly crashed at the Paris Air Show; the accident had been caused by a speck of dirt in the air feed lines of the nozzle control motor, which had caused the engine nozzles to stick. XP831 was later fully repaired and resumed development flying. All the pilots involved survived.
John Farley’s definitive story of the Harrier (and P.1127) Lecture
The record-breaking Hunter .
