A swept wing is a wing angled either backward or occasionally forward from its root rather than perpendicular to the fuselage.
152-513: 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,
304-553: A 6,500 lbf (29 kN) Rolls-Royce Avon 103 engine from an English Electric Canberra bomber. The second prototype was fitted with a 7,550 lbf (33.6 kN) Avon 107 turbojet. Hawker's third prototype was powered by an 8,000 lbf (36 kN) Armstrong Siddeley Sapphire 101. Production Hunters were fitted with either the Avon or the Sapphire engine. Early on in the Hunter's service
456-461: A German mathematician and engineer at Braunschweig , discovered Tricomi's work in the process of applying the hodograph method to transonic flow near the end of World War II. He focused on the nonlinear thin-airfoil compressible flow equations, the same as what Tricomi derived, though his goal of using these equations to solve flow over an airfoil presented unique challenges. Guderley and Hideo Yoshihara, along with some input from Busemann, later used
608-487: A Sapphire, the third prototype flew on 30 November 1952. On 16 March 1953, the first production standard Hunter F.1 , fitted with a single 7,600 lbf (34 kN) Avon 113 turbojet, made its first flight. The first 20 aircraft were, in effect, a pre-production series and featured a number of "one-off" modifications such as blown flaps and area ruled fuselage. On 7 September 1953, the sole Hunter Mk 3 (the modified first prototype, WB 188 ) flown by Neville Duke broke
760-411: A daytime jet-powered interceptor aircraft. Camm promptly prepared a new design for a swept-winged fighter that would be powered by the upcoming Rolls-Royce Avon turbojet. The Avon's major advantage over the earlier Nene engine, as used in the earlier Sea Hawk, was adoption of the axial compressor , which allowed for a much smaller engine diameter and provided greater thrust; this single engine gave roughly
912-445: A far distance they are invariably supersonic. Supernovae explosions are accompanied by supersonic flows and shock waves. Bow shocks formed in solar winds are a direct result of transonic winds from a star. It had been long thought that a bow shock was present around the heliosphere of our solar system, but this was found not to be the case according to IBEX data published in 2012. Swept wing Swept wings have been flown since
1064-453: A fatal plane accident. He lost control of the plane when a shock wave caused by supersonic airflow developed over the wing, causing it to stall. Virden flew well below the speed of sound at Mach 0.675, which brought forth the idea of different airflows forming around the plane. In the 40s, Kelly Johnson became one of the first engineers to investigate the effect of compressibility on aircraft. However, contemporary wind tunnels did not have
1216-485: A flow speed close to or at Mach 1 does not allow the streamtubes (3D flow paths) to contract enough around the object to minimize the disturbance, and thus the disturbance propagates. Aerodynamicists struggled during the earlier studies of transonic flow because the then-current theory implied that these disturbances– and thus drag– approached infinity as local Mach number approached 1, an obviously unrealistic result which could not be remedied using known methods. One of
1368-420: A flurry of orders being issued; the need for capable modern interceptors was felt to be so pressing that the RAF was willing to consider accepting interim fighter aircraft while more capable fighters would continue to be pursued. In particular, the RAF felt that a pair of proposed fighter aircraft from Hawker Aircraft and Supermarine were of high importance and thus placed orders for these proposed fighters 'off
1520-488: A leading edge sweep of 35° and slight anhedral , the tailplanes and fin are also swept. The Hunter's aerodynamic qualities were increasingly infringed upon by modifications in later production models, such as the addition of external containers to collect spent gun cartridges, underwing fuel tanks to increase range, leading edge extensions to resolve pitch control difficulties, and a large ventral air brake. Late-production F.6s also featured an "all-moving tailplane" , in which
1672-509: A local indentation of the fuselage above and below the wing root. This proved to not be very effective. During the development of the Douglas DC-8 airliner, uncambered airfoils were used in the wing root area to combat the unsweeping. Swept wings on supersonic aircraft usually lie within the cone-shaped shock wave produced at the nose of the aircraft so they will "see" subsonic airflow and work as subsonic wings. The angle needed to lie behind
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#17328450664891824-462: A means of creating positive longitudinal static stability . For a low-speed aircraft, swept wings may be used to resolve problems with the center of gravity , to move the wing spar into a more convenient location, or to improve the sideways view from the pilot's position. By 1905, Dunne had already built a model glider with swept wings followed by the powered Dunne D.5 , and by 1913 he had constructed successful powered variants that were able to cross
1976-524: A nose-mounted ranging radar , providing range input to the gyro gunsight for air-to-air gunnery only. Other equipment included pylon-mounted underwing external fuel tanks, a forward-facing gun camera, and large streamlined pods for collecting expended shell cases beneath the gun pack. These were nicknamed "Sabrinas", after the buxom actress of the time . Several variants were fitted with tail-mounted brake parachutes. Typically, export Hunters were equipped to be compatible with additional types of missiles, such as
2128-647: A number of compatible napalm bombs were also maintained for intended use by the Hunters. In the interceptor role, the Hunters were supplemented by a surface-to-air missile (SAM) defence system also procured from the United Kingdom, based on the Bristol Bloodhound . In case of unserviceable airstrips, Swiss Air Force jets would take off from adjacent highways, using them as improvised runways. The Patrouille Suisse flight demonstration team were prominent fliers of
2280-477: A pair of proposed fighter aircraft equipped with swept wings from Hawker Aircraft and Supermarine , the Hawker Hunter and Supermarine Swift respectively, and successfully pressed for orders to be placed 'off the drawing board' in 1950. On 7 September 1953, the sole Hunter Mk 3 (the modified first prototype, WB 188 ) flown by Neville Duke broke the world air speed record for jet-powered aircraft, attaining
2432-505: A rapid increase in drag from about Mach 0.8, and it is the fuel costs of the drag that typically limits the airspeed. Attempts to reduce wave drag can be seen on all high-speed aircraft. Most notable is the use of swept wings , but another common form is a wasp-waist fuselage as a side effect of the Whitcomb area rule . Transonic speeds can also occur at the tips of rotor blades of helicopters and aircraft. This puts severe, unequal stresses on
2584-579: A record-breaking speed of Mach 1.06 (700 miles per hour (1,100 km/h; 610 kn)). The news of a successful straight-wing supersonic aircraft surprised many aeronautical experts on both sides of the Atlantic, as it was increasingly believed that a swept-wing design not only highly beneficial but also necessary to break the sound barrier. During the final years of the Second World War, aircraft designer Sir Geoffrey de Havilland commenced development on
2736-453: A reflex curve at the trailing edge. This results in a much weaker shock wave towards the rear of the upper wing surface and a corresponding increase in critical mach number. Shock waves require energy to form. This energy is taken out of the aircraft, which has to supply extra thrust to make up for this energy loss. Thus the shocks are seen as a form of drag . Since the shocks form when the local air velocity reaches supersonic speeds, there
2888-567: A revised fuselage, and a single jet exhaust at the rear. On 19 June 1950, the P.1081 conducted its maiden flight, and was promising enough to draw interest from the Royal Australian Air Force (RAAF); however, further development was stalled by difficulties with the engine's reheat . In 1951, the sole P.1081 prototype was lost in a crash. In 1946, the British Air Ministry issued Specification F.43/46 , which sought
3040-456: A single 6,500 lbf (28.91 kN ) Avon 103 engine. The second prototype, which was fitted with production-standard avionics, armament and a 7,550 lbf (33.6 kN) Avon 107 turbojet, first flew on 5 May 1952. As an insurance against development problems on the part of the Avon engine, Hawker modified the design to accommodate another axial turbojet, the 8,000 lbf (36 kN) Armstrong Siddeley Sapphire 101. Fitted with
3192-485: A single month. Both sides claimed victory in the air war, Pakistan claimed to have destroyed 104 aircraft against its own losses of 19, while India claimed to have destroyed 73 enemy aircraft and lost 35 of its own. Despite the intense fighting, the conflict was effectively a stalemate. IAF Hunters performed extensive operations during the Indo-Pakistani War of 1971 ; India had six combat-ready squadrons of Hunters at
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#17328450664893344-562: A single pack that could be removed from the aircraft for rapid re-arming and maintenance. Unusually, the barrels of the cannon remained in the aircraft while the pack was removed and changed. In the two-seat version, either a single 30 mm ADEN cannon was carried or, in some export versions, two, with a removable ammunition tank. Later versions of the Hunter were fitted with SNEB pods; these were 68 mm (2.68 in) rocket projectiles in 18-round Matra pods, providing an effective strike capability against ground targets. The Hunter featured
3496-494: A single ventral airbrake. This meant, however, that the airbrake could not be used for landings. To address the problem of range, a production Hunter F.1 was fitted with a modified wing featuring bag-type fuel tanks in the leading edge and two (or 4 on later aircraft) "wet" hardpoints for 100-gallon drop tanks. The resulting Hunter F.4 first flew on 20 October 1954, and entered service in March 1955. A distinctive Hunter feature added on
3648-499: A singular solution of Tricomi's equations to analytically solve the behavior of transonic flow over a double wedge airfoil , the first to do so with only the assumptions of thin-airfoil theory. Although successful, Guderley's work was still focused on the theoretical, and only resulted in a single solution for a double wedge airfoil at Mach 1. Walter Vincenti , an American engineer at Ames Laboratory , aimed to supplement Guderley's Mach 1 work with numerical solutions that would cover
3800-431: A speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number , but transonic flow is seen at flight speeds close to the speed of sound (343 m/s at sea level), typically between Mach 0.8 and 1.2. The issue of transonic speed (or transonic region) first appeared during World War II. Pilots found as they approached
3952-420: A swept wing as it travels through the air. The airflow over a swept wing encounters the wing at an angle. That angle can be broken down into two vectors, one perpendicular to the wing, and one parallel to the wing. The flow parallel to the wing has no effect on it, and since the perpendicular vector is shorter (meaning slower) than the actual airflow, it consequently exerts less pressure on the wing. In other words,
4104-534: A swept wing the wing panels on the Douglas DC-1 outboard of the nacelles also had slight sweepback for similar reasons. 2. to provide longitudinal stability for tailless aircraft, e.g. Messerschmitt Me 163 Kometuu . 3. most commonly to increase Mach-number capability by delaying to a higher speed the effects of compressibility (abrupt changes in the density of the airflow), e.g. combat aircraft, airliners and business jets. Other reasons include: 1. enabling
4256-412: A wing carry-through box position to achieve a desired cabin size, e.g. HFB 320 Hansa Jet . 2. providing static aeroelastic relief which reduces bending moments under high g-loadings and may allow a lighter wing structure. For a wing of given span, sweeping it increases the length of the spars running along it from root to tip. This tends to increase weight and reduce stiffness. If the fore-aft chord of
4408-434: A wing is generated by the airflow over it from front to rear. With increasing span-wise flow the boundary layers on the surface of the wing have longer to travel, and so are thicker and more susceptible to transition to turbulence or flow separation, also the effective aspect ratio of the wing is less and so air "leaks" around the wing tips reducing their effectiveness. The spanwise flow on swept wings produces airflow that moves
4560-477: A world speed record. On 12 April 1948, a D.H.108 did set a world's speed record at 973.65 km/h (605 mph), it subsequently became the first jet aircraft to exceed the speed of sound. Around this same timeframe, the Air Ministry introduced a program of experimental aircraft to examine the effects of swept wings, as well as the delta wing configuration. Furthermore, the Royal Air Force (RAF) identified
4712-521: Is Mach 1 and the Prandtl–Glauert singularity . In astrophysics, wherever there is evidence of shocks (standing, propagating or oscillating), the flow close by must be transonic, as only supersonic flows form shocks. All black hole accretions are transonic. Many such flows also have shocks very close to the black holes. The outflows or jets from young stellar objects or disks around black holes can also be transonic since they start subsonically and at
Hawker Hunter - Misplaced Pages Continue
4864-410: Is a certain " critical mach " speed where sonic flow first appears on the wing. There is a following point called the drag divergence mach number where the effect of the drag from the shocks becomes noticeable. This is normally when the shocks start generating over the wing, which on most aircraft is the largest continually curved surface, and therefore the largest contributor to this effect. Sweeping
5016-507: Is normally used to mean "swept back", but variants include forward sweep , variable sweep wings and oblique wings in which one side sweeps forward and the other back. The delta wing is also aerodynamically a form of swept wing. There are three main reasons for sweeping a wing: 1. to arrange the center of gravity of the aircraft and the aerodynamic center of the wing to coincide more closely for longitudinal balance, e.g. Messerschmitt Me 163 Komet and Messerschmitt Me 262 . Although not
5168-429: Is placed in an airstream at an angle of yaw – i.e., it is swept back. Now, even if the local speed of the air on the upper surface of the wing becomes supersonic, a shock wave cannot form there because it would have to be a sweptback shock – swept at the same angle as the wing – i.e., it would be an oblique shock. Such an oblique shock cannot form until the velocity component normal to it becomes supersonic." To visualize
5320-447: Is rare and the wing must be unusually rigid. There are two sweep angles of importance, one at the leading edge for supersonic aircraft and the other 25% of the way back from the leading edge for subsonic and transonic aircraft. Leading edge sweep is important because the leading edge has to be behind the mach cone to reduce wave drag. The quarter chord (25%) line is used because subsonic lift due to angle of attack acts there and, up until
5472-419: Is that disturbances within the flow are relatively small, which allows mathematicians and engineers to linearize the compressible flow equations into a relatively easily solvable set of differential equations for either wholly subsonic or supersonic flows. This assumption is fundamentally untrue for transonic flows because the disturbance caused by an object is much larger than in subsonic or supersonic flows;
5624-483: The Sabre dance in reference to the number of North American F-100 Super Sabres that crashed on landing as a result. Reducing pitch-up to an acceptable level has been done in different ways such as the addition of a fin known as a wing fence on the upper surface of the wing to redirect the flow to a streamwise direction. The MiG-15 was one example of an aircraft fitted with wing fences. Another closely related design
5776-522: The AIM-9 Sidewinder air-to-air missile and the AGM-65 Maverick air-to-surface missile . The Hunter is a conventional swept wing all-metal monoplane. The fuselage is of monocoque construction, with a removable rear section for engine maintenance. The engine is fed through triangular air intakes in the wing roots and has a single jetpipe in the rear of the fuselage. The mid-mounted wings have
5928-538: The Brunei Revolt in 1962, the Royal Air Force deployed Hunters and Gloster Javelins over Brunei to provide support for British ground forces; Hunters launched both dummy and real strafing runs on ground targets to intimidate and pin down rebels. In one event , several Bruneian and expatriate hostages were due to be executed by rebels. Hunter aircraft flew over Limbang while Royal Marines from 42 Commando rescued
6080-521: The Empire Test Pilots' School at MoD Boscombe Down . The Hunter is unusual among swept wing jet aircraft in being able to be safely spun inverted. This would be demonstrated to students of the school. As early as 1953 the first Hunter flew over Denmark, when test pilot Neville Duke demonstrated the F.1 over Copenhagen Airport. During this demonstration, the pilot broke the sound barrier in a shallow dive. Air Force officials were very impressed with
6232-683: The English Channel . The Dunne D.5 was exceptionally aerodynamically stable for the time, and the D.8 was sold to the Royal Flying Corps ; it was also manufactured under licence by Starling Burgess to the United States Navy amongst other customers. Dunne's work ceased with the onset of war in 1914, but afterwards the idea was taken up by G. T. R. Hill in England who designed a series of gliders and aircraft to Dunne's guidelines, notably
Hawker Hunter - Misplaced Pages Continue
6384-654: The Hawk T.1 entered service in the mid-1970s. Two-seat trainer versions of the Hunter, the T.7 and T.8, remained in use for training and secondary roles by the RAF and Royal Navy until the early 1990s; when the Blackburn Buccaneer retired from service. The requirement for Hunter trainers disappeared so the Buccaneer-orientated trainers were retired, leaving the RN T.8Ms to soldier on for a while longer. Hunters were also used by
6536-475: The Hawker P.1052 , which was essentially a Sea Hawk outfitted with a 35-degree swept wing. Performing its first flight in 1948, the P.1052 demonstrated good performance and conducted several carrier trials, but was ultimately determined to not warrant further development into a production aircraft. As a private venture, Hawker proceeded to convert the second P.1052 prototype into the Hawker P.1081 with swept tailplanes,
6688-571: The Hawker Sea Hawk for the Royal Navy , the majority of Specifications issued by the Air Ministry for fighter-sized aircraft during the late 1940s were restricted to research purposes. Aviation author Derek Wood describes this policy as being: "a fatal error of judgement which was to cost Britain a complete generation of fighters and heavy bomber aircraft". As the Cold War arose in the late 1940s,
6840-455: The Junkers Ju 287 or HFB 320 Hansa Jet . However, larger sweep suitable for high-speed aircraft, like fighters, was generally impossible until the introduction of fly by wire systems that could react quickly enough to damp out these instabilities. The Grumman X-29 was an experimental technology demonstration project designed to test the forward swept wing for enhanced maneuverability during
6992-654: The Mikoyan-Gurevich MiG-21 ; large numbers of Russian-built fighters had increasingly supplemented the ageing Hunters in the interceptor role by 1970. The Hunter was to play a major role during the Indo-Pakistani War of 1965 ; along with the Folland Gnat , the Hunter was India's primary air defence fighter, and regularly engaged in dogfights with the Pakistani F-86 Sabres and F-104 Starfighters. The aerial war saw both sides conducting thousands of sorties in
7144-587: The North American F-86 Sabre , the Folland Gnat , and the Hawker Hunter; a pair of Hunters were loaned to the Swiss for further trials and testing. In January 1958, the government of Switzerland chose to terminate its independent fighter aircraft project, the in-development FFA P-16 , instead choosing to order 100 Hunters to replace its existing fleet of de Havilland Vampire fighters. Further development of
7296-791: The Radfan campaign against insurgents attempting to overthrow the Federation of South Arabia . SAS forces would routinely call in air strikes that required considerable precision, and, predominantly using 3-inch high explosive rockets and 30 mm ADEN cannon, the Hunter proved an able ground-attack platform. Both squadrons continued operations with their Hunters until the UK withdrew from Aden in November 1967. Hunters were flown by No.63 , No. 234 and No. 79 Squadrons acting in training roles for foreign and Commonwealth students. These remained in service until after
7448-904: The Rhodesian Bush War , the Second Congo War , the Six-Day War , the War of Attrition and the Yom Kippur War . 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 . During 1945,
7600-544: The Second World War came to a close and a new postwar Labour government, headed by Clement Attlee , came to power in Britain. The incoming Attlee government's initial stance on defence was that no major conflict would occur for at least a decade, and thus there would be no need to develop or to procure any new aircraft until 1957. In accordance with this policy, aside from a small number of exceptions such as what would become
7752-570: The Westland-Hill Pterodactyl series. However, Dunne's theories met with little acceptance amongst the leading aircraft designers and aviation companies at the time. The idea of using swept wings to reduce high-speed drag was developed in Germany in the 1930s. At a Volta Conference meeting in 1935 in Italy, Adolf Busemann suggested the use of swept wings for supersonic flight. He noted that
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#17328450664897904-418: The de Havilland Comet , which would become the world's first jet airliner. An early design consideration was whether to apply the new swept-wing configuration. Thus, an experimental aircraft to explore the technology, the de Havilland DH 108 , was developed by the firm in 1944, headed by project engineer John Carver Meadows Frost with a team of 8–10 draughtsmen and engineers. The DH 108 primarily consisted of
8056-412: The 1930s and 1940s, but the breakthrough mathematical definition of sweep theory is generally credited to NACA 's Robert T. Jones in 1945. Sweep theory builds on other wing lift theories. Lifting line theory describes lift generated by a straight wing (a wing in which the leading edge is perpendicular to the airflow). Weissinger theory describes the distribution of lift for a swept wing, but does not have
8208-405: The 1980s. The Sukhoi Su-47 Berkut is another notable demonstrator aircraft implementing this technology to achieve high levels of agility. To date, no highly swept-forward design has entered production. The first successful aeroplanes adhered to the basic design of rectangular wings at right angles to the body of the machine. Such a layout is inherently unstable; if the weight distribution of
8360-476: The Avon engines proved to have poor surge margins, and worryingly suffered compressor stalls when the cannon were fired, sometimes resulting in flameouts . The practice of "fuel dipping", reducing fuel flow to the engine when the cannon were fired, was a satisfactory solution. Although the Sapphire did not suffer from the flameout problems of the Avon and had better fuel economy, Sapphire-powered Hunters suffered many engine failures. The RAF elected to persevere with
8512-503: The Avon engines. The F.2, which used the Armstrong-Siddeley Sapphire engine, did not suffer from this defect. Further problems occurred; ejected cannon ammunition links had a tendency to strike and damage the underside of the fuselage, and diverting the gas emitted by the cannon during firing was another necessary modification. The original split-flap airbrakes caused adverse changes in pitch trim and were quickly replaced by
8664-525: The Avon to simplify supply and maintenance, since the Canberra bomber used the same engine. The RAF sought more thrust than was available from the Avon 100 series; in response Rolls-Royce developed the Avon 200 series engine. This was an almost wholly new design, equipped with a new compressor to put an end to surge problems, an annular combustion chamber, and an improved fuel control system. The resulting Avon 203 produced 10,000 lbf (44 kN) of thrust, and
8816-471: The F 8 and F 18 wings that defended Stockholm . The J 34 was armed with four 30 mm (1.18 in) cannon and two Sidewinders . The Swedish Air Force's aerobatic team Acro Hunters used five J 34s during the late 1950s. The J 34s were gradually replaced by supersonic Saab J 35 Draken and reassigned to less prominent air wings, F 9 in Gothenburg and F 10 in Ängelholm, during the 1960s. A project to improve
8968-428: The F.4 was the pair of blisters under the cockpit, which collected spent ammunition links to prevent airframe damage. Crews dubbed them " Sabrinas " after the contemporary movie star. The Sapphire-powered version of the F.4 was designated the Hunter F.5. The RAF later received Hunters equipped with an improved Avon engine. The Avon 203 produced 10,000 lbf (44 kN) of thrust and was fitted to XF833 , which became
9120-456: The Hawker Hunter for several decades. Squadron aircraft were fitted with smoke generators on the engine exhausts and, later on, were painted in a distinctive red-and-white livery. The group officially formed on 22 August 1964, and used the Hunter as its display aircraft until it was withdrawn from use in 1994, the team continued to perform flight display using newer aircraft. The Hunter fleet endured several attempts to procure successor aircraft to
9272-668: The Hawker P.1040 for the RAF, but the demonstrator failed to interest them. Further modifications to the basic design resulted in the Hawker Sea Hawk carrier-based fighter . However, the Sea Hawk possessed a straight wing and was powered by the Rolls-Royce Nene turbojet engine, both features that rapidly became obsolete. Seeking better performance and fulfilment of the Air Ministry Specification E.38/46 , Sydney Camm designed
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#17328450664899424-725: The Hunter FGA.9 variant. The FGA.9 saw frontline use from 1960 to 1971, alongside the closely related Hunter FR.10 tactical reconnaissance variant. The Hunters were also used by two RAF display units; the Black Arrows of No. 111 Squadron who set a record by looping and barrel rolling 22 Hunters in formation, and later the Blue Diamonds of No. 92 Squadron who flew 16 Hunters. In Aden in May 1964, Hunter FGA.9s and FR.10s of No. 43 Squadron RAF and No. 8 Squadron RAF were used extensively during
9576-695: The Hunter carried on as a day fighter until its retirement in 1974. The last flight of the Hunter in RDAF service was carried out on 30 April 1974. The entire fleet was initially preserved at Aalborg Air Base, in the hopes of a future sale to other users. No such sale was ever carried out, but 16 F.Mk. 51s and four T-Mk.53 (two additional T.Mk. 53 had been purchased from the Netherlands in 1967) were sent back to Hawker Siddeley in December 1975. Ultimately, most Hunters were sold either to private buyers or to military museums around
9728-659: The Hunter in the air-to-air role with a more modern fighter aircraft, the Northrop F-5E Tiger II . The Hunter remained in a key role within the Swiss Air Force; like the RAF's Hunter fleet, the type transitioned to become the country's primary ground attack platform, replacing the Venom. While the Swiss Hunters already had more armament options than the RAF aircraft, being cleared to carry Oerlikon 80 mm rockets instead of
9880-467: The Hunter was a significantly different aircraft to fly, compared to older types such as the Meteor, the need for a two-seat trainer soon arose, and the RDAF took delivery of two T.Mk. 53 two-seat trainers in 1958. In contrast to most other users of the Hunter, RDAF never converted the Hunter to the fighter-bomber role. Although some studies and experiments carried out in 1959, the project never materialised and
10032-622: The Hunter was the FGA.9, on which the majority of export versions were based. Although the Supermarine Swift had initially been politically favoured by the British government, the Hunter proved far more successful, and had a lengthy service life with various operators, in part due to its low maintenance requirements and operating costs, while further development of the Swift programme was cancelled in 1955. As
10184-426: The Hunter's performance, giving it only a maximum flight endurance of about an hour. A fatal accident occurred on 8 February 1956, when a flight of eight Hunters was diverted to another airfield owing to adverse weather conditions. Six of the eight aircraft ran out of fuel and crashed , killing one pilot. Another difficulty encountered during the aircraft's introduction was the occurrence of surging and stalling with
10336-651: The Hunter, including the Dassault Mirage F1 , the Saab 37 Viggen , and several Soviet models, the Indian government announced its intention to procure 200 Jaguars, a large portion of which were to be assembled domestically, in October 1978. In 1996, the last of the IAF's Hunters were phased out of service, the last squadron operating Hunters later converting to the newer Sukhoi Su-30MKI . In
10488-630: 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 ,
10640-436: The RAF came to recognise that it would urgently require the development and procurement of fighters equipped with features such as swept wings . By this time, it had also become apparent that newly developed jet propulsion would form the future of fighter aircraft development. Many companies were quick to devise their own designs to harness this means of propulsion. Hawker Aviation 's chief designer, Sydney Camm , had proposed
10792-444: The RAF received newer aircraft capable of supersonic speeds to perform the air interceptor role, many Hunters were modified and re-equipped for undertaking ground-attack and reconnaissance missions instead. Hunters deemed surplus to the RAF's requirements were also quickly refurbished for continued service abroad. The Hunter would be procured by a considerable number of foreign nations. In addition to former RAF aircraft, roughly half of
10944-687: The actual aircraft speed is, this becomes a problem during slow-flight phases, such as takeoff and landing. There have been various ways of addressing the problem, including the variable-incidence wing design on the Vought F-8 Crusader , and swing wings on aircraft such as the F-14 , F-111 , and the Panavia Tornado . The term "swept wing" is normally used to mean "swept back", but other swept variants include forward sweep , variable sweep wings and oblique wings in which one side sweeps forward and
11096-434: The air does have time to react, and is pushed spanwise by the angled leading edge, towards the wing tip. At the wing root, by the fuselage, this has little noticeable effect, but as one moves towards the wingtip the airflow is pushed spanwise not only by the leading edge, but the spanwise moving air beside it. At the tip the airflow is moving along the wing instead of over it, a problem known as spanwise flow . The lift from
11248-421: The air would be added to the previously perpendicular airflow, resulting in an airflow over the wing at an angle to the leading edge. This angle results in airflow traveling a greater distance from leading edge to trailing edge, and thus the air pressure is distributed over a greater distance (and consequently lessened at any particular point on the surface). This scenario is identical to the airflow experienced by
11400-453: The aircraft a good ferry range. The Hunter F.6 was given the company designation Hawker P.1099 . During the Suez Crisis of 1956, Hunter F.5s of No. 1 and No. 34 Squadrons based at RAF Akrotiri in Cyprus flew escort for English Electric Canberra bombers on offensive missions into Egypt. For most of the conflict the Hunters engaged in local air defence due to their lack of range. During
11552-414: The aircraft changes even slightly, the wing will want to rotate so its front moves up (weight moving rearward) or down (forward) and this rotation will change the development of lift and cause it to move further in that direction. To make an aircraft stable, the normal solution is to place the weight at one end and offset this with an opposite downward force at the other - this leads to the classic layout with
11704-422: The aircraft to reach speeds closer to Mach 1. One limiting factor in swept wing design is the so-called "middle effect". If a swept wing is continuous - an oblique swept wing - the pressure isobars will be swept at a continuous angle from tip to tip. However, if the left and right halves are swept back equally, as is common practice, the pressure isobars on the left wing in theory will meet the pressure isobars of
11856-418: The airspeed over the wing was dominated by the normal component of the airflow, not the freestream velocity, so by setting the wing at an angle the forward velocity at which the shock waves would form would be higher (the same had been noted by Max Munk in 1924, although not in the context of high-speed flight). Albert Betz immediately suggested the same effect would be equally useful in the transonic. After
12008-413: The angle of attack at the tip, thus reducing the bending moment on the wing, as well as somewhat reducing the chance of tip stall. However, the same effect on forward-swept wings produces a wash-in effect that increases the angle of attack promoting tip stall. Small amounts of sweep do not cause serious problems, and had been used on a variety of aircraft to move the spar into a convenient location, as on
12160-401: The basic concept of simple sweep theory, consider a straight, non-swept wing of infinite length, which meets the airflow at a perpendicular angle. The resulting air pressure distribution is equivalent to the length of the wing's chord (the distance from the leading edge to the trailing edge). If we were to begin to slide the wing sideways ( spanwise ), the sideways motion of the wing relative to
12312-409: The best wingtip shape for sonic speeds. After World War II , major changes in aircraft design were seen to improve transonic flight. The main way to stabilize an aircraft was to reduce the speed of the airflow around the wings by changing the chord of the plane wings, and one solution to prevent transonic waves was swept wings. Since the airflow would hit the wings at an angle, this would decrease
12464-485: The capability to create wind speeds close to Mach 1 to test the effects of transonic speeds. Not long after, the term "transonic" was defined to mean "across the speed of sound" and was invented by NACA director Hugh Dryden and Theodore von Kármán of the California Institute of Technology. Initially, NACA designed "dive flaps" to help stabilize the plane when reaching transonic flight. This small flap on
12616-412: The capability to include chordwise pressure distribution. There are other methods that do describe chordwise distributions, but they have other limitations. Jones' sweep theory provides a simple, comprehensive analysis of swept wing performance. An explanation of how the swept wing works was offered by Robert T. Jones : "Assume a wing is a cylinder of uniform airfoil cross-section, chord and thickness and
12768-511: The cone increases with increasing speed, at Mach 1.3 the angle is about 45 degrees, at Mach 2.0 it is 60 degrees. The angle of the Mach cone formed off the body of the aircraft will be at about sin μ = 1/M (μ is the sweep angle of the Mach cone) When a swept wing travels at high speed, the airflow has little time to react and simply flows over the wing almost straight from front to back. At lower speeds
12920-522: The demonstration and since the Royal Danish Air Force (RDAF) were looking for a replacement for the Gloster Meteors in service at the time, the Hunter was a natural choice. Consequently, a contract for delivery of 30 F. Mk. 51 was signed on 3 July 1954. RDAF took delivery of the first two of these on 31 January 1956 and nine months later all 30 Hunters had been delivered to 724 Squadron. Since
13072-511: The drawing board' in 1950. The reasoning behind these two aircraft being ordered in 1950 was intended to serve as an insurance policy in the event of either one of these projects failing to produce a viable aircraft; these two aircraft would later become known as the Supermarine Swift and the Hawker Hunter respectively. On 20 July 1951, the P.1067 made its maiden flight , flown by Neville Duke , from RAF Boscombe Down , powered by
13224-511: The early 1950s, the Swedish Air Force saw the need for an interceptor that could reach enemy bombers at a higher altitude than the Saab J 29 Tunnan that formed the backbone of the fighter force. A contract for 120 Hawker Hunter Mk 50s (equivalent to the Mk 4) was therefore signed on 29 June 1954 and the first aircraft was delivered on 26 August 1955. The model was designated J 34 and was assigned to
13376-412: The effects of compressibility in transonic and supersonic aircraft because of the reduced pressures. This allows the mach number of an aircraft to be higher than that actually experienced by the wing. There is also a negative aspect to sweep theory. The lift produced by a wing is directly related to the speed of the air over the wing. Since the airflow speed experienced by a swept wing is lower than what
13528-421: The elderly 3-inch rockets used by the RAF, to carry bombs from both inner and outer pylons and to launch AIM-9 Sidewinder air-to-air missiles, the change to a primary air-to-ground role resulted in the Hunter 80 upgrade, adding chaff/flare dispensers, BL755 cluster bombs and the ability to carry AGM-65 Maverick missiles. Transonic Transonic (or transsonic ) flow is air flowing around an object at
13680-460: The engine in front and the control surfaces at the end of a long boom with the wing in the middle. This layout has long been known to be inefficient. The downward force of the control surfaces needs further lift from the wing to offset. The amount of force can be decreased by increasing the length of the boom, but this leads to more skin friction and weight of the boom itself. This problem led to many experiments with different layouts that eliminates
13832-431: The entire tailplane pivoted to provide better transonic flight control. The elevator was retained as part of the all-moving tailplane. The airframe of the Hunter consists of six interchangeable major sections: the forward fuselage (housing the cockpit and armament pack), center fuselage (including the integral wing roots and air duct intakes), rear fuselage, tail unit assembly, and two individually produced wings. Production
13984-535: The fastest aircraft of the era were only approaching 400 km/h (249 mph).The presentation was largely of academic interest, and soon forgotten. Even notable attendees including Theodore von Kármán and Eastman Jacobs did not recall the presentation 10 years later when it was re-introduced to them. Hubert Ludwieg of the High-Speed Aerodynamics Branch at the AVA Göttingen in 1939 conducted
14136-407: The first Hunter F.6. Some other revisions on the F.6 included a revised fuel tank layout, the centre fuselage tanks being replaced by new slightly smaller ones in the rear fuselage; the distinctive "dogtooth" leading edge extension (Mod 533) to alleviate the pitch-up problem; the "Mod 228" wing, with increased structural strength and four (rather than the previous two) "wet" hardpoints, finally giving
14288-562: The first methods used to circumvent the nonlinearity of transonic flow models was the hodograph transformation. This concept was originally explored in 1923 by an Italian mathematician named Francesco Tricomi , who used the transformation to simplify the compressible flow equations and prove that they were solvable. The hodograph transformation itself was also explored by both Ludwig Prandtl and O.G. Tietjen's textbooks in 1929 and by Adolf Busemann in 1937, though neither applied this method specifically to transonic flow. Gottfried Guderley,
14440-565: The first wind tunnel tests to investigate Busemann's theory. Two wings, one with no sweep, and one with 45 degrees of sweep were tested at Mach numbers of 0.7 and 0.9 in the 11 x 13 cm wind tunnel. The results of these tests confirmed the drag reduction offered by swept wings at transonic speeds. The results of the tests were communicated to Albert Betz who then passed them on to Willy Messerschmitt in December 1939. The tests were expanded in 1940 to include wings with 15, 30 and -45 degrees of sweep and Mach numbers as high as 1.21. With
14592-442: The freestream conditions around the rest of the aircraft, and as the flow enters an adverse pressure gradient in the aft section of the wing, a discontinuity emerges in the form of a shock wave as the air is forced to rapidly slow and return to ambient pressure. At the point where the density drops, the local speed of sound correspondingly drops and a shock wave can form. This is why in conventional wings, shock waves form first after
14744-518: The hostages in a fierce battle. In the following years of the Borneo Confrontation , Hunters were deployed along with other RAF aircraft in Borneo and Malaya . The Hunter F.6 was retired from its day fighter role in the RAF by 1963, being replaced by the much faster English Electric Lightning interceptor. Many F.6s were then given a new lease of life in the close air support role, converting into
14896-658: The immediate post-war era, several nations were conducting research into high speed aircraft. In the United Kingdom, work commenced during 1943 on the Miles M.52 , a high-speed experimental aircraft equipped with a straight wing that was developed in conjunction with Frank Whittle 's Power Jets company, the Royal Aircraft Establishment (RAE) in Farnborough , and the National Physical Laboratory . The M.52
15048-526: The increasingly chaotic battlefield conditions, which ultimately led to the retreat of Pakistan's ground forces. Hunters were also used for many ground-attack missions and raids inside Pakistan's borders, such as the high-profile bombing of the Attock Oil refinery to limit Pakistani fuel supplies. In the aftermath of the conflict, Pakistan claimed to have shot down a total of 32 of India's Hunters. Due to unfavourable currency conditions and conflicting pressures on
15200-438: The indigenous P-16 was discontinued. This initial order for 100 single-seat Hunters consisted of 12 refurbished RAF F.6s, and 88 new-built F.58s. Swiss Hunters were operated as interceptors, with a secondary ground-attack role; from 1963 onwards, the outboard wing pylons were modified to carry two AIM-9 Sidewinder air-to-air missiles. In the ground-attack role, the Swiss Air Force maintained an arsenal of conventional iron bombs,
15352-472: The introduction of jets in the later half of the Second World War , the swept wing became increasingly applicable to optimally satisfying aerodynamic needs. The German jet-powered Messerschmitt Me 262 and rocket-powered Messerschmitt Me 163 suffered from compressibility effects that made both aircraft very difficult to control at high speeds. In addition, the speeds put them into the wave drag regime, and anything that could reduce this drag would increase
15504-494: The introduction of supercritical sections, the crest was usually close to the quarter chord. Typical sweep angles vary from 0 for a straight-wing aircraft, to 45 degrees or more for fighters and other high-speed designs. Shock waves can form on some parts of an aircraft moving at less than the speed of sound. Low-pressure regions around an aircraft cause the flow to accelerate, and at transonic speeds this local acceleration can exceed Mach 1. Localized supersonic flow must return to
15656-522: The large-calibre gun demanded by earlier specifications). Initially fitted with a single air intake in the nose and a T-tail , the project rapidly evolved into the more familiar Hunter shape. The intakes were moved to the wing roots to make room for weapons and radar in the nose, and a more conventional tail arrangement was devised as a result of stability concerns. In 1950, the outbreak of the Korean War and Britain's heavy involvement in this conflict led to
15808-399: The maximum Thickness/Chord and why all airliners designed for cruising in the transonic range (above M0.8) have supercritical wings that are flatter on top, resulting in minimized angular change of flow to upper surface air. The angular change to the air that is normally part of lift generation is decreased and this lift reduction is compensated for by deeper curved lower surfaces accompanied by
15960-551: The military budget, several prospective procurements of modern aircraft such as the SEPECAT Jaguar and the British Aerospace Sea Harrier were put on hold following the 1971 war; the indigenously developed HAL HF-24 Marut had also not been as successful as hoped, thus the IAF decided to retain the ageing fleets of Hunters and English Electric Canberra bombers. After considering several foreign aircraft to replace
16112-473: The modified first prototype broke the world air speed record for aircraft, achieving a speed of 727.63 mph (1,171.01 km/h; 632.29 kn). 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
16264-463: The nearly 2,000 Hunters produced had been manufactured specifically for overseas customers. The Hunter would be in operational service with the RAF for over 30 years. As late as 1996, hundreds were still in active service with various operators across the world. The single-seat fighter versions of the Hunter were armed with four 30 mm (1.18 in) ADEN cannon , with 150 rounds of ammunition per gun. The cannon and ammunition boxes were contained in
16416-420: The need for the downward force. One such wing geometry appeared before World War I , which led to early swept wing designs. In this layout, the wing is swept so that portions lie far in front and in back of the center of gravity (CoG), with the control surfaces behind it. The result is a weight distribution similar to the classic layout, but the offsetting control force is no longer a separate surface but part of
16568-433: The other back. The delta wing also incorporates the same advantages as part of its layout. Sweeping a wing forward has approximately the same effect as rearward in terms of drag reduction, but has other advantages in terms of low-speed handling where tip stall problems simply go away. In this case the low-speed air flows towards the fuselage, which acts as a very large wing fence. Additionally, wings are generally larger at
16720-421: The pairing of the front fuselage of the de Havilland Vampire to a swept wing and small vertical tail; it was the first British swept wing jet, unofficially known as the "Swallow". It first flew on 15 May 1946, a mere eight months after the project's go-ahead. Company test pilot and son of the builder, Geoffrey de Havilland Jr ., flew the first of three aircraft and found it extremely fast – fast enough to try for
16872-435: The performance of the J 34 resulted in one Hunter being fitted with a Swedish-designed afterburner in 1958. While this significantly increased the engine's thrust, there was little improvement in overall performance, so the project was shelved. The last of the J 34s was retired from service in 1969. In 1957, the Swiss Air Force performed an extensive evaluation of several aircraft for a prospective purchase; competitors included
17024-458: The performance of their aircraft, notably the notoriously short flight times measured in minutes. This resulted in a crash program to introduce new swept wing designs, both for fighters as well as bombers . The Blohm & Voss P 215 was designed to take full advantage of the swept wing's aerodynamic properties; however, an order for three prototypes was received only weeks before the war ended and no examples were ever built. The Focke-Wulf Ta 183
17176-504: The pioneer days of aviation. Wing sweep at high speeds was first investigated in Germany as early as 1935 by Albert Betz and Adolph Busemann , finding application just before the end of the Second World War . It has the effect of delaying the shock waves and accompanying aerodynamic drag rise caused by fluid compressibility near the speed of sound , improving performance. Swept wings are therefore almost always used on jet aircraft designed to fly at these speeds. The term "swept wing"
17328-402: The presentation the host of the meeting, Arturo Crocco , jokingly sketched "Busemann's airplane of the future" on the back of a menu while they all dined. Crocco's sketch showed a classic 1950s fighter design, with swept wings and tail surfaces, although he also sketched a swept propeller powering it. At the time, however, there was no way to power an aircraft to these sorts of speeds, and even
17480-422: The problem. In addition to pitch-up there are other complications inherent in a swept-wing configuration. For any given length of wing, the actual span from tip-to-tip is shorter than the same wing that is not swept. There is a strong correlation between low-speed drag and aspect ratio , the span compared to chord, so a swept wing always has more drag at lower speeds. In addition, there is extra torque applied by
17632-412: The range of transonic speeds between Mach 1 and wholly supersonic flow. Vincenti and his assistants drew upon the work of Howard Emmons as well as Tricomi's original equations to complete a set of four numerical solutions for the drag over a double wedge airfoil in transonic flow above Mach 1. The gap between subsonic and Mach 1 flow was later covered by both Julian Cole and Leon Trilling , completing
17784-403: The right wing on the centerline at a large angle. As the isobars cannot meet in such a fashion, they will tend to curve on each side as they near the centerline, so that the isobars cross the centerline at right angles to the centerline. This causes an "unsweeping" of the isobars in the wing root region. To combat this unsweeping, German aerodynamicist Dietrich Küchemann proposed and had tested
17936-431: The root anyway, which allows them to have better low-speed lift. However, this arrangement also has serious stability problems. The rearmost section of the wing will stall first causing a pitch-up moment pushing the aircraft further into stall similar to a swept back wing design. Thus swept-forward wings are unstable in a fashion similar to the low-speed problems of a conventional swept wing. However unlike swept back wings,
18088-406: The rotor blade and may lead to accidents if it occurs. It is one of the limiting factors of the size of rotors and the forward speeds of helicopters (as this speed is added to the forward-sweeping [leading] side of the rotor, possibly causing localized transonics). Issues with aircraft flight relating to speed first appeared during the supersonic era in 1941. Ralph Virden, a test pilot, crashed in
18240-508: The same power as the two Rolls-Royce Derwents of the Gloster Meteors, a fighter aircraft that would be replaced by the envisioned new aircraft. In March 1948, the Air Ministry issued a revised Specification F.3/48, which demanded a speed of 629 mph (1,010 km/h) at 45,000 ft (13,700 m) and a high rate of climb, while carrying an armament of four 20 mm (0.79 in) or two 30 mm (1.18 in) cannon (rather than
18392-483: The sound barrier the airflow caused aircraft to become unsteady. Experts found that shock waves can cause large-scale separation downstream, increasing drag, adding asymmetry and unsteadiness to the flow around the vehicle. Research has been done into weakening shock waves in transonic flight through the use of anti-shock bodies and supercritical airfoils . Most modern jet powered aircraft are engineered to operate at transonic air speeds. Transonic airspeeds see
18544-402: The stagnation point on the leading edge of any individual wing segment further beneath the leading edge, increasing effective angle of attack of wing segments relative to its neighbouring forward segment. The result is that wing segments farther towards the rear operate at increasingly higher angles of attack promoting early stall of those segments. This promotes tip stall on back-swept wings, as
18696-509: The start of the conflict. Pakistani infantry and armoured forces attacked the Indian outpost of Longewala in an event now known as the Battle of Longewala . Six IAF Hunters stationed at Jaisalmer Air Force Base were able to halt the Pakistani advance at Longewala by conducting non-stop bombing raids. The aircraft attacked Pakistani tanks, armoured personnel carriers and gun positions and contributed to
18848-540: The swept wing design used by most modern jet aircraft, as this design performs more effectively at transonic and supersonic speeds. In its advanced form, sweep theory led to the experimental oblique wing concept. Adolf Busemann introduced the concept of the swept wing and presented this in 1935 at the Fifth Volta Conference in Rome. Sweep theory in general was a subject of development and investigation throughout
19000-401: The tail of the aircraft will reach supersonic flight while the nose of the aircraft is still in subsonic flight. A bubble of supersonic expansion fans terminating by a wake shockwave surround the tail. As the aircraft continues to accelerate, the supersonic expansion fans will intensify and the wake shockwave will grow in size until infinity is reached, at which point the bow shockwave forms. This
19152-725: The time was still awaiting the delivery of large numbers of ex-RAF Hunters. By the outbreak of the Sino-Indian War in 1962, India had assembled one of the largest air forces in Asia, and the Hunter was the nation's primary and most capable interceptor. During the conflict, the Hunter demonstrated its superiority over China's Russian-sourced MiGs and gave India a strategic advantage in the air. India's aerial superiority deterred Chinese Ilyushin Il-4 bombers from attacking targets within India. In 1962, India had selected to procure its first supersonic-capable fighter,
19304-411: The tips are most rearward, while delaying tip stall for forward-swept wings, where the tips are forward. With both forward and back-swept wings, the rear of the wing will stall first creating a nose-up moment on the aircraft. If not corrected by the pilot the plane will pitch up, leading to more of the wing stalling and more pitch up in a divergent manner. This uncontrollable instability came to be known as
19456-450: The tips on a forward swept design will stall last, maintaining roll control. Forward-swept wings can also experience dangerous flexing effects compared to aft-swept wings that can negate the tip stall advantage if the wing is not sufficiently stiff. In aft-swept designs, when the airplane maneuvers at high load factor the wing loading and geometry twists the wing in such a way as to create washout (tip twists leading edge down). This reduces
19608-404: The tips to bend upwards in normal flight. Backwards sweep causes the tips to reduce their angle of attack as they bend, reducing their lift and limiting the effect. Forward sweep causes the tips to increase their angle of attack as they bend. This increases their lift causing further bending and hence yet more lift in a cycle which can cause a runaway structural failure. For this reason forward sweep
19760-437: The transonic behavior of the airfoil by the early 1950s. At transonic speeds supersonic expansion fans form intense low-pressure, low-temperature areas at various points around an aircraft. If the temperature drops below the dew point a visible cloud will form. These clouds remain with the aircraft as it travels. It is not necessary for the aircraft as a whole to reach supersonic speeds for these clouds to form. Typically,
19912-700: The type; in the case of the Dassault Mirage III this had been due to excessive cost overruns and poor project management rather than the attributes of the Hunter itself. A second attempt to replace the Hunter resulted in a competition between the French Dassault Milan and the U.S. LTV A-7 Corsair II . Although the A-7 was eventually chosen as the winner, it would not be purchased and further 30 refurbished Hunters (22 F.58As and eight T.68 trainers) were purchased in 1974 instead. By 1975, plans were laid to replace
20064-419: The underside of the plane slowed the plane to prevent shock waves, but this design only delayed finding a solution to aircraft flying at supersonic speed. Newer wind tunnels were designed, so researchers could test newer wing designs without risking test pilots' lives. The slotted-wall transonic tunnel was designed by NASA and allowed researchers to test wings and different airfoils in transonic airflow to find
20216-472: The wing also remains the same, the distance between leading and trailing edges reduces, reducing its ability to resist twisting (torsion) forces. A swept wing of given span and chord must therefore be strengthened and will be heavier than the equivalent unswept wing. A swept wing typically angles backward from its root rather than forwards. Because wings are made as light as possible, they tend to flex under load. This aeroelasticity under aerodynamic load causes
20368-448: The wing experiences airflow that is slower - and at lower pressures - than the actual speed of the aircraft. One of the factors that must be taken into account when designing a high-speed wing is compressibility , which is the effect that acts upon a wing as it approaches and passes through the speed of sound . The significant negative effects of compressibility made it a prime issue with aeronautical engineers. Sweep theory helps mitigate
20520-402: The wing has the effect of reducing the curvature of the body as seen from the airflow, by the cosine of the angle of sweep. For instance, a wing with a 45 degree sweep will see a reduction in effective curvature to about 70% of its straight-wing value. This has the effect of increasing the critical Mach by 30%. When applied to large areas of the aircraft, like the wings and empennage , this allows
20672-478: The wing thickness and chord ratio. Airfoils wing shapes were designed flatter at the top to prevent shock waves and reduce the distance of airflow over the wing. Later on, Richard Whitcomb designed the first supercritical airfoil using similar principles. Prior to the advent of powerful computers, even the simplest forms of the compressible flow equations were difficult to solve due to their nonlinearity . A common assumption used to circumvent this nonlinearity
20824-469: The wing to the fuselage which has to be allowed for when establishing the transfer of wing-box loads to the fuselage. This results from the significant part of the wing lift which lies behind the attachment length where the wing meets the fuselage. Sweep theory is an aeronautical engineering description of the behavior of airflow over a wing when the wing's leading edge encounters the airflow at an oblique angle. The development of sweep theory resulted in
20976-524: The wing, which would have existed anyway. This eliminates the need for separate structure, making the aircraft have less drag and require less total lift for the same level of performance. These layouts inspired several flying wing gliders and some powered aircraft during the interwar years. The first to achieve stability was British designer J. W. Dunne who was obsessed with achieving inherent stability in flight. He successfully employed swept wings in his tailless aircraft (which, crucially, used washout ) as
21128-404: The world air speed record for jet-powered aircraft, attaining a speed of 727.63 mph (1,171.01 km/h) over Littlehampton , West Sussex . This world record stood for less than three weeks before being broken on 25 September 1953 by the Hunter's early rival, the Supermarine Swift, flown by Michael Lithgow . The Hunter entered service with the Royal Air Force as an interceptor aircraft. It
21280-573: The world. Only one example (47-401/E-401) was reserved for museum use in Denmark and currently resides in Danmarks Flymuseum in Stauning. In 1954, India arranged to purchase Hunters as a part of a wider arms deal with Britain, ordering 140 Hunter single-seat fighters at the same time that Pakistan announced its purchase of several North American F-86 Sabre jet fighters. The Indian Air Force (IAF)
21432-417: 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
21584-564: Was another swept wing fighter design, but was also not produced before the war's end. In the post-war era, Kurt Tank developed the Ta 183 into the IAe Pulqui II , but this proved unsuccessful. A prototype test aircraft, the Messerschmitt Me P.1101 , was built to research the tradeoffs of the design and develop general rules about what angle of sweep to use. When it was 80% complete, the P.1101
21736-543: Was captured by US forces and returned to the United States , where two additional copies with US-built engines carried on the research as the Bell X-5 . Germany's wartime experience with the swept wings and its high value for supersonic flight stood in strong contrast to the prevailing views of Allied experts of the era, who commonly espoused their belief in the impossibility of manned vehicles travelling at such speeds. During
21888-427: Was divided up so major sections could be completed individually and manufacturing of the type could be dispersed to reduce vulnerability to attack. Establishing initial full-rate production for the type was difficult, as manufacturing the Hunter required the development of 3,250 tool designs and the procurement of 40,000 fixtures, jigs, and tools. The P.1067 first flew from RAF Boscombe Down on 20 July 1951, powered by
22040-460: Was envisioned to be capable of achieving 1,000 miles per hour (1,600 km/h) in level flight, thus enabling the aircraft to potentially be the first to exceed the speed of sound in the world. In February 1946, the programme was abruptly discontinued for unclear reasons. It has since been widely recognised that the cancellation of the M.52 was a major setback in British progress in the field of supersonic design. Another, more successful, programme
22192-482: 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 22 Hunters in formation, and later the Blue Diamonds , who flew 16 aircraft. The Hunter
22344-634: Was the US's Bell X-1 , which also was equipped with a straight wing. According to Miles Chief Aerodynamicist Dennis Bancroft, the Bell Aircraft company was given access to the drawings and research on the M.52. On 14 October 1947, the Bell X-1 performed the first manned supersonic flight, piloted by Captain Charles "Chuck" Yeager , having been drop launched from the bomb bay of a Boeing B-29 Superfortress and attained
22496-523: Was the addition of a dogtooth notch to the leading edge, used on the Avro Arrow interceptor. Other designs took a more radical approach, including the Republic XF-91 Thunderceptor 's wing that grew wider towards the tip to provide more lift at the tip. The Handley Page Victor was equipped with a crescent wing , with three values of sweep, about 48 degrees near the wing root where the wing
22648-570: Was the engine for the Hunter F.6. The Hunter F.1 entered service with the Royal Air Force in July 1954. It was the first high-speed jet aircraft equipped with radar and fully powered flight controls to go into widespread service with the RAF. The Hunter replaced the Gloster Meteor, the Canadair Sabre , and the de Havilland Venom jet fighters in service. Initially, low internal fuel capacity restricted
22800-584: Was the first jet aircraft produced by Hawker for the RAF. From the outset it was clear that the type had exceptional performance, being the first RAF aircraft capable of effectively matching the English Electric Canberra bomber. The Hunter also set numerous aviation records, including absolute speed records. The type was also lauded for its quick turnaround time, enabled by features such as its removable gun pack and pressurised fuelling system, and for its easy handling in flight. The definitive version of
22952-445: Was the first to operate the Hunter T.66 trainers, placing an initial order in 1957. The more powerful engine was considered beneficial in a hot environment, allowing for greater takeoff weights. During the 1960s, Pakistan investigated the possibility of buying as many as 40 English Electric Lightnings, but Britain was unenthusiastic about the potential sales opportunity because of the damage it would do to its relations with India, which at
23104-471: Was thickest, a 38 degree transition length and 27 degrees for the remainder to the tip. Modern solutions to the problem no longer require "custom" designs such as these. The addition of leading-edge slats and large compound flaps to the wings has largely resolved the issue. On fighter designs, the addition of leading-edge extensions , which are typically included to achieve a high level of maneuverability, also serve to add lift during landing and reduce
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