The BAE Systems Hawk is a British single-engine, jet-powered advanced trainer aircraft. It was first flown at Dunsfold, Surrey, in 1974 as the Hawker Siddeley Hawk, and subsequently produced by its successor companies, British Aerospace and BAE Systems, respectively. It has been used in a training capacity and as a low-cost combat aircraft.
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.
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). 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.
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”. 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. 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. 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. 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. 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”.
On 13 February 1961, XP831 performed its first conventional flight, flown by Bill Bedford and lasting for 22 minutes. 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. 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. 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
Content coming soon – we are new society so keen to add new information in the coming months.
Banner Photo credit : Andy Lawson, BAe Systems
Night-time Ex-RAF Harrier at Cosford, credit www.steviebeats.co.uk
The Hawker Hunter is a transonic British jet-powered fighter aircraft that was developed by Hawker Aircraft for the Royal Air Force (RAF) during the late 1940s and early 1950s. It was designed to take advantage of the newly developed Rolls-Royce Avon turbojet engine and the swept wing, and was the first jet-powered aircraft produced by Hawker to be procured by the RAF. On 7 September 1953, the modified first prototype broke the world air speed record for jet-powered aircraft, achieving a speed of 727.63 mph (1,171.01 km/h; 632.29 kn).
The Hunter flying from Dunsfold
The Hunter in use with the RAF
The RAF Black Arrows formation team, 111 Squadron:
The single-seat Hunter was introduced to service in 1954 as a manoeuvrable day interceptor aircraft, quickly succeeding first-generation jet fighters in RAF service such as the Gloster Meteor and the de Havilland Venom. The all-weather/night fighter role was filled by the Gloster Javelin. Successively improved variants of the type were produced, adopting increasingly more capable engine models and expanding its fuel capacity amongst other modifications being implemented. Hunters were also used by two RAF display teams: the “Black Arrows”, who on one occasion looped a record-breaking 24 Hunters in formation, and later the “Blue Diamonds”, who flew 16 aircraft. The Hunter was also widely exported, serving with a total of 21 overseas air forces.
During the 1960s, following the introduction of the supersonic English Electric Lightning in the interceptor role, the Hunter transitioned to being operated as a fighter-bomber and for aerial reconnaissance missions, using dedicated variants for these purposes. Two-seat variants remained in use for training and secondary roles with the RAF and the Royal Navy until the early 1990s. Sixty years after its original introduction it was still in active service, being operated by the Lebanese Air Force until 2014.
The Hunter saw combat service in a range of conflicts with several operators, including the Suez Crisis, the Aden Emergency, the Sino-Indian War, the Indo-Pakistani War of 1965, the Indo-Pakistani War of 1971, the Rhodesian Bush War, the Second Congo War, the Six-Day War, the War of Attrition, the Yom Kippur War, and the 2007 Lebanon conflict. Overall, 1,972 Hunters were manufactured by Hawker Aircraft and its successor, Hawker Siddeley, as well as being produced under licence overseas. In British service, the Hunter was replaced in its principal roles by the Lightning, the Hawker Siddeley Harrier and the McDonnell Douglas F-4 Phantom II.
How to fly a Hunter:
For a comprehensive history of the Hunter.
The North American B-25 Mitchell is an American twin-engine, medium bomber manufactured by North American Aviation (NAA). It was named in honor of Major General William “Billy” Mitchell, a pioneer of U.S. military aviation. Used by many Allied air forces, the B-25 served in every theater of World War II and after the war ended many remained in service, operating across four decades. Produced in numerous variants, nearly 10,000 Mitchells rolled from NAA factories. These included a few limited models, such as the United States Marine Corps’ PBJ-1 patrol bomber and the United States Army Air Forces’ F-10 reconnaissance aircraft and AT-24 trainers.
Primemeads is an early 17th century oak timberframed farmhouse, with a possible smoke hood and early diamond mullioned window. Brick house with decorative dentil course shows the house built in two phases. It was Listed by Historic England in April 2017. Home to the test pilot Neville Duke – in 1955 Duke set the world air speed record of 727.63mph flying the Hunter WB188.
WB188, the first P.1067 and Neville Duke’s record breaking aircraft
Please note: The aerodrome is private land and an active airfield. Access is not permitted to some of the buildings and features and we strongly discourage access without permission.
Dunsfold Airfield was cleared of woodland, farmland and buildings to form the Canadian Air Force airbase in 1942. Units of Canadian troops cleared land requisitioned from the people to form runways, perimeter roads and after little more than one month the first aircraft had landed. The old Brighton Road from Godalming was relocated so that it no longer ran through the site at Pains Hill. The old cast iron milestones were amended by one mile to reflect the additional mileage diversion. Most farm buildings and farm houses were removed with the exception of the Chiddingfold Kennels (now Honey Mead), Primemeads Farmhouse (originally Stillwells Farm) and Broadmeads Cottage (now referred to as Canada House). The latter was moved to the southern perimeter and now stands alongside Benbow Lane.
The three runways and perimeter track are very complete, built with a pioneering form of construction and still retain original features such as light fittings and cast iron drainage channels. In 1942 this airfield was an expression of a technical and social innovation of the period to meet demands of the war time. It has been adapted to suit the needs and development of the Vertical Take Off and Landing aircraft with the VTOL platforms for these ‘jump jets’.
Research and Sources: Surrey History Centre, Airfield Research Group, Brooklands Museum Archive, Imperial War Museum –March 2017
Work on the airfield started 11th may 1942 with a bold estimate that work would be completed in 18 weeks. This was a challenge that the 2nd Battalion Royal Canadian Engineers, 2nd Road Construction Company & the Canadian Forestry Corps were capable of meeting using explosives and some of the heavy machinery supplied from the USA under the lease lend arrangements.
Tree stumps were blasted and from May 27th concrete was being poured in two shifts 18 hours a day. One of the obstacles encountered in the construction of the 45ft wide 3 mile perimeter road was Broadmead Cottage. It straddled the route to be taken and a swift demolition was required to keep construction within the tight timeframe. Sergeant Fred Kreugar realised special skills were required to deal with the building so ordered Sergeant Whidden to deal with the issue.
Dunsfold: 'Before the war it was the most remote village in Surrey: now, well hidden, an airfield tests jet fighters.'
Nikolaus Pevsner, Buildings of England: Surrey
Historic England explains that Local Planning Authorities are obliged to designate as conservation areas any parts of their own area that are of special architectural or historic interest, the character and appearance of which it is desirable to preserve or enhance. Waverley Borough Council Planning Department are considering an application for designation of Dunsfold Aerodrome as a Conservation Area. There is a consultation process concluding on April 28th 2017. Please read what follows and look at the references to Historic England’s documents. Then if you want to support DAHS and make comments about the designation you can make them on the Waverley website. It is a simple questionnaire.
You may be surprised to know that former military airfields can – and do – become designated as Conservation Areas. This is because conservation areas are not just about ‘old buildings’. They have a much wider role to play than that. In the words of Historic England (formerly English Heritage);
‘The totality of an aerodrome cannot be captured through statutory designation alone, and other approaches such as conservation area protection….. have been shown to be appropriate’ (Historic England (4))
In respect of Dunsfold Aerodrome, the case for establishing a Conservation Area is very much about the historical context, the people, and the events (of national and international importance) that are inextricably linked to the site. But it is also about the appropriate management and preservation of the large number of heritage buildings still existing, the future of which is currently uncertain. Most members of the public are unaware of the existence of these structures as the site is still private and largely ‘hidden’. It is not coincidental that at this point in time Historic England is considering the designation of at least 10 structures on Dunsfold Aerodrome – in other words ‘listing’ them. This would have an important bearing on the designation of the site as a Conservation Area.
Plan of Dunsfold Heritage Assets click to expand:
‘The vast majority of nationally significant airfield structures will be most appropriately protected through listing…..Another mechanism by which the significance of an airfield can be highlighted as a historic landscape, is through conservation area status.’ (Historic England (5)).
Conservation of a special place such as Dunsfold Aerodrome is about the complex processes through which we as individuals or as groups define ourselves and our relationships with the natural and cultural aspects of the airfield. It is about a sense of place – profoundly important for individual and community identity, and the ‘significance’ of this airfield as a heritage asset. Currently, Historic England recognises Dunsfold Aerodrome as an Undesignated Heritage Asset; if it were to be granted conservation area status this would raise it to Designated Heritage Asset status.
There is a recognised procedure for appraisal, designation and management of a Conservation Area (Historic England (6)). Appraisal of an area for conservation can include establishing its significance for a number of reasons:-
- History, Landscape and Identities
- Rural Sense of Place
- Urban Sense of Place
- Cultural Landscapes
- Conservation, Biodiversity and Tourism
DAHS exists to research and make public all of the history of what has been called ‘Surrey’s most secret airfield’*, to celebrate historical achievements, and preserve precious assets and memories for the benefit of current and future generations. We believe that the right and proper way of doing that is for all statutory bodies, local councils and stakeholders to work together to establish a robust framework for the airfield that will inform and guide its future management and development, recognising its heritage value. A conservation area covering the site would be an ideal means of achieving this.
What makes Dunsfold Airfield special?
- The relatively ‘untouched’ nature of the 1942-built airfield
- The survival of a large number of key physical assets, including the runways, in their original form
- Home to the development of a number of iconic British military aircraft; including the Hunter, the Hawk and the Harrier ‘jump jet’ – world class technology that led to military and economic success.
- Berlin Airlift – Dunsfold Airfield helped to avert what would probably have been a humanitarian disaster.
- 3 permanent runways designed for the WWII bombers and latter used to test new aviation technology.
- Wings and Wheels – major air show and motorsport event attracting 25,000 visitors and over 1000 participants.
- Home to the BBCs Top Gear programme watched in 214 territories worldwide and has an estimated global audience of 350 million
Examples of former military airfields that have been given Conservation Area status include;