The Northrop YF-17 was a prototype lightweight fighter aircraft designed for the United States Air Force's Lightweight Fighter technology evaluation program. The LWF was initiated because many in the fighter community believed that aircraft like the F-15 Eagle were too large and expensive for many combat roles; the YF-17 was the culmination of a long line of Northrop designs, beginning with the N-102 Fang in 1956, continuing through the F-5 family. Although it lost the LWF competition to the F-16 Fighting Falcon, the YF-17 was selected for the new Naval Fighter Attack Experimental program. In enlarged form, the F/A-18 Hornet was adopted by the United States Navy and United States Marine Corps to replace the A-7 Corsair II and F-4 Phantom II, complementing the more expensive F-14 Tomcat; this design, conceived as a small and lightweight fighter, was scaled up to the Boeing F/A-18E/F Super Hornet, similar in size to the original F-15. The aircraft's main design elements date to early 1965, from the internal Northrop project N-300.
The N-300 was itself derived from the F-5E, features a longer fuselage, small leading-edge root extensions, more powerful GE15-J1A1 turbojets, rated at 9,000 lbf each. The wing was elevated to increase ordnance flexibility; the N-300 further evolved into the P-530 Cobra, which uses 13,000 lbf GE15-J1A5 engines, with a small.25 bypass ratio leading to the nickname "leaky turbojet". The bypass was only a cooling stream for the rear of the engine, allowing the engine bay to be constructed of lighter, cheaper materials; the P-530's wing planform and nose section was similar to the F-5, with a trapezoidal shape formed by a sweep of 20° at the quarter-chord line, an unswept trailing edge, but was over double the area, with 400 sq ft as opposed to 186 sq ft of the F-5E. Shoulder mounted, the wings were shifted down to the mid position, its most distinctive new feature were the LERXs. They enabled maneuvering at angles of attack exceeding 50°, by providing about 50% additional lift; the extensions trapped airflow under them at high angles of attack, ensuring airflow into the engines.
The resemblance to the head of a cobra lead to the adoption of the nickname "Cobra" unofficially used for the YF-17. When the Lightweight Fighter program was announced in 1971, Northrop modified the P-530 into the P-600 design that would be designated YF-17A. Whereas the P-530 was intended as a multi-role aircraft, the P-600 was to be an air-to-air demonstrator, the cannon moved from the underside of the fuselage, to the upper part. Design of the YF-17 and the prototype YJ101 engine, consumed over a million man-hours, 5,000 hours of wind tunnel testing; the YF-17 was constructed of aluminum, in conventional semi-monocoque stressed-skin construction, though over 900 lb of its structure were graphite/epoxy composite. The small nose contained a simple ranging radar; the cockpit sported an ejection seat inclined at 18°, a bubble canopy, a head-up display. The thin wings carried no fuel, in areas such as the leading and trailing edge and the LERX, were composed of a Nomex honeycomb core with composite facesheets.
The rear of the aircraft featured twin all-moving stabilators of aluminum over a honeycomb core, twin vertical stabilizers of a conventional construction. Like the wings, the leading and trailing edges were constructed of composite facesheets over honeycomb core. A composite speedbrake was located between the engines; the aircraft was powered by a pair of 14,400-pound-force General Electric YJ101-GE-100 turbofans, a development of the GE15, mounted next to each other to minimize thrust asymmetry in the event of an engine loss. For ease of maintenance, the engines are mounted in a steady-rest that allows removal from below the aircraft, without disturbing the empennage controls; each engine drove an independent hydraulic system. Unlike the P-530, the YF-17 sported a partial fly-by-wire control scheme, formally called the electronic control augmentation system, utilizing ailerons and stabilators for primary flight control. Studies showed a single vertical stabilizer was insufficient at high angles of attack, it was changed to twin vertical stabilizers, canted at 45°, resulting in a "relaxed longitudinal stability" design, which enhances maneuverability.
Northrop was not yet confident in fly-by-wire controls and retained mechanically-signaled flight controls. The resulting aircraft, unveiled on 28 January 1971, advertised a maximum weight of 40,000 lb and maximum speed of Mach 2, but stirred little interest among foreign buyers; the first prototype was rolled out at Hawthorne on 4 April 1974. Chouteau afterwards remarked that, "When our designers said that in the YF-17 they were going to give the airplane back to the pilot, they meant it. It's a fighter pilot's fighter." The second YF-17 first flew on 21 August. Through 1974, the YF-17 competed against the General Dynamics YF-16; the two YF-17 prototypes flew 288 test flights. The YF-17 attained a top speed of Mach 1.95, a peak load factor of 9.4 g, a maximum altitude of over 50,000 ft. It could attain a sustained 34° angle of attack in level flight, 63° in a climb at 50 kt; the U. S. Navy was not involved as a participant in the LWF program. In August 1974, Congress directed the Navy to mak
Convair F-102 Delta Dagger
The Convair F-102 Delta Dagger was an American interceptor aircraft, built as part of the backbone of the United States Air Force's air defenses in the late 1950s. Entering service in 1956, its main purpose was to intercept invading Soviet strategic bomber fleets during the Cold War. Designed and manufactured by Convair, 1,000 F-102s were built. A member of the Century Series, the F-102 was the USAF's first operational supersonic interceptor and delta-wing fighter, it used an internal weapons bay to carry both guided rockets. As designed, it could not achieve Mach 1 supersonic flight until redesigned with area ruling; the F-102 replaced subsonic fighter types such as the Northrop F-89 Scorpion, by the 1960s, it saw limited service in the Vietnam War in bomber escort and ground-attack roles. It was supplemented by McDonnell F-101 Voodoos and by McDonnell Douglas F-4 Phantom IIs. Many of the F-102s were transferred from the active duty Air Force to the Air National Guard by the mid-to-late 1960s, with the exception of those examples converted to unmanned QF-102 Full Scale Aerial Target drones, the type was retired from operational service in 1976.
The follow-on replacement was the Mach-2 Convair F-106 Delta Dart, an extensive redesign of the F-102. On 8 October 1948, the board of senior officers of the U. S. Air Force made recommendations that the service organize a competition for a new interceptor scheduled to enter service in 1954. Four months on 4 February 1949, the USAF approved the recommendation and prepared to hold the competition the following year. In November 1949, the Air Force decided that the new aircraft would be built around a fire-control system; the FCS was to be designed before the airframe to ensure compatibility. The airframe and FCS together were called the weapon system. In January 1950, the USAF Air Materiel Command issued request for proposals to 50 companies for the FCS, of which 18 responded. By May, the list was revised downward to 10. Meanwhile, a board at the U. S. Department of Defense headed by Major General Gordon P. Saville reviewed the proposals, distributed some to the George E. Valley-led Air Defense Engineering Committee.
Following recommendations by the committee to the Saville Board, the proposals were further reduced to two competitors, Hughes Aircraft and North American Aviation. Although the Valley Committee thought it was best to award the contract to both companies, Hughes was chosen by Saville and his team on 2 October 1950. Proposals for the airframe were issued on 18 June 1950, in January 1951 six manufacturers responded. On 2 July 1954, three companies, Convair and Lockheed won the right to build a mockup; until Convair had done research into delta-winged aircraft, experimenting with different designs, two of which fell under the name P-92. Of the three, the best design was to win the production contract under the name "Project MX-1554". In the end, Convair emerged as the victor with its design, designated "XF-102", after Lockheed dropped out and Republic built only a mockup; the development of three different designs was too expensive and in November, only Convair was allowed to continue with its Model 8-80.
To speed development, it was proposed to equip the prototypes and pre-production aircraft with the less-powerful Westinghouse J40 turbojet. Continued delays to the J67 and MA-1 FCS led to the decision to place an interim aircraft with the J40 and a simpler fire control system into production as the F-102A; the failure of the J40 led to the Pratt & Whitney J57 turbojet with afterburner, rated with 10,000 pounds-force of thrust being substituted for the prototypes and F-102As. This aircraft was intended to be temporary, pending the development of the F-102B, which would employ the more advanced Curtiss-Wright J67, a licensed derivative of the Bristol-Siddeley Olympus, still in development; the F-102B would evolve to become the F-106A, dubbed the "Ultimate Interceptor". The prototype YF-102 made its first flight on 23 October 1953, at Edwards AFB, but was lost in an accident nine days later; the second aircraft flew on 11 January 1954. Transonic drag was much higher than expected, the aircraft was limited to Mach 0.98, with a ceiling of 48,000 ft, far below the requirements.
To solve the problem and save the F-102, Convair embarked on a major redesign, incorporating the discovered area rule, while at the same time simplifying production and maintenance. The redesign entailed lengthening the fuselage by 11 ft, being "pinched" at the midsection, with two large fairings on either side of the engine nozzle, with revised intakes and a new, narrower canopy. A more powerful model of the J57 was fitted, the aircraft structure was lightened; the first revised aircraft, designated YF-102A flew on 20 December 1954, 118 days after the redesign started, exceeding Mach 1 the next day. The revised design demonstrated a speed of Mach 1.22 and a ceiling of 53,000 ft. These improvements were sufficient for the Air Force to allow production of the F-102, with a new production contract signed in March 1954; the production F-102A had the Hughes MC-3 fire control system upgraded in service to the MG-10. It had a three-segment internal weapons bay under the fuselage for air-to-air missiles.
Initial armament was three pairs of GAR-1/2/3/4 Falcon missiles, which included both infrared homing and semi-active radar homing variants. The doors of the two forward bays each had tubes for 12 FFARs (for a t
Indo-Pakistani wars and conflicts
Since the partition of British India in 1947 and creation of modern states of India and Pakistan, the two countries have been involved in a number of wars and military stand-offs. The Kashmir issue has been the main cause of all major conflicts between the two countries with the exception of the Indo-Pakistani War of 1971 where conflict originated due to turmoil in erstwhile East Pakistan; the Partition of India came about in the aftermath of World War II, when both Great Britain and British India were dealing with the economic stresses caused by the war and its demobilisation. It was the intention of those who wished for a Muslim state to come from British India to have a clean partition between independent and equal "Pakistan" and "Hindustan" once independence came; the partition itself, according to leading politicians such as Mohammed Ali Jinnah, leader of the All India Muslim League, Jawaharlal Nehru, leader of the Indian National Congress, should have resulted in peaceful relations. As the Hindu and Muslim populations were scattered unevenly in the whole country, the partition of British India into India and Pakistan in 1947 was not possible along religious lines.
Nearly one third of the Muslim population of British India remained in India. Inter-communal violence between Hindus and Muslims resulted in between 500,000 and 1 million casualties. Princely-ruled territories, such as Kashmir and Hyderabad, were involved in the Partition. Rulers of these territories had the choice of joining Pakistan; the war called the First Kashmir War, started in October 1947 when Pakistan feared that the Maharaja of the princely state of Kashmir and Jammu would accede to India. Following partition, princely states were left to choose whether to join India or Pakistan or to remain independent. Jammu and Kashmir, the largest of the princely states, had a majority Muslim population and significant fraction of Hindu population, all ruled by the Hindu Maharaja Hari Singh. Tribal Islamic forces with support from the army of Pakistan attacked and occupied parts of the princely state forcing the Maharaja to sign the Instrument of Accession of the princely state to the Dominion of India to receive Indian military aid.
The UN Security Council passed Resolution 47 on 22 April 1948. The fronts solidified along what came to be known as the Line of Control. A formal cease-fire was declared at 23:59 on the night of 1 January 1949. India gained control of about two-thirds of the state whereas Pakistan gained a third of Kashmir; the Pakistan controlled. This war started following Pakistan's Operation Gibraltar, designed to infiltrate forces into Jammu and Kashmir to precipitate an insurgency against rule by India. India retaliated by launching a full-scale military attack on West Pakistan; the seventeen-day war caused thousands of casualties on both sides and witnessed the largest engagement of armored vehicles and the largest tank battle since World War II. The hostilities between the two countries ended after a ceasefire was declared following diplomatic intervention by the Soviet Union and USA and the subsequent issuance of the Tashkent Declaration. India had the upper hand over Pakistan; this war was unique in the way that it did not involve the issue of Kashmir, but was rather precipitated by the crisis created by the political battle brewing in erstwhile East Pakistan between Sheikh Mujibur Rahman, Leader of East Pakistan, Yahya Khan and Zulfikar Ali Bhutto, leaders of West Pakistan.
This would culminate in the declaration of Independence of Bangladesh from the state system of Pakistan. Following Operation Searchlight and the 1971 Bangladesh atrocities, about 10 million Bengalis in East Pakistan took refuge in neighbouring India. India intervened in the ongoing Bangladesh liberation movement. After a large scale pre-emptive strike by Pakistan, full-scale hostilities between the two countries commenced. Pakistan attacked at several places along India's western border with Pakistan, but the Indian Army held their positions; the Indian Army responded to the Pakistan Army's movements in the west and made some initial gains, including capturing around 5,795 square miles of Pakistan territory. Within two weeks of intense fighting, Pakistani forces in East Pakistan surrendered to the joint command of Indian and Bangladeshi forces following which the People's Republic of Bangladesh was created; this war saw the highest number of casualties in any of the India-Pakistan conflicts, as well as the largest number of prisoners of war since the Second World War after the surrender of more than 90,000 Pakistani military and civilians.
In the words of one Pakistani author, "Pakistan lost half its navy, a quarter of its air force and a third of its army". Known as the Kargil War, this conflict between the two countries was limited. During early 1999, Pakistani troops infiltrated across the Line of Control and occupied Indian territory in the Kargil district. India responded by launching a major military and diplomatic offensive to drive out the Pakistani infiltrators. Two months into the conflict, Indian troops had retaken most of the ridges that were encroached by the infiltrators. According to official count, an estimated 75%–80% of the intruded area and nearly all high ground was back under Indian control. Fearing large-scale escalation in military conflict, the international community, led by the United States, increa
Virginia Air and Space Center
The Virginia Air and Space Center is a museum and educational facility in Hampton, Virginia that serves as the visitors center for NASA's Langley Research Center and Langley Air Force Base. The museum features an IMAX digital theater and offers summer aeronautic- and space-themed camps for children; the museum's permanent collection is housed in a three-story glass atrium accessible from two exhibit floors with an additional catwalk level available for viewing suspended aircraft from above. Volunteers maintain an amateur radio exhibit displaying historic radio equipment; the exhibit participates in the Space Amateur Radio Experiment where visitors can periodically talk to astronauts aboard the International Space Station. The gallery emphasizes hands-on and immersive experiments on flight concepts such as control surfaces and propeller design, experiences such as flight simulators; the gallery features numerous aircraft suspended from the roof in the main gallery. Most are restored and have close ties to flight research performed at area NASA, Air Force and Naval installations.
A McDonnell Douglas DC-9-32 passenger aircraft donated by AirTran Airways dominates the gallery. Visitors can sit in cockpit, first class and coach seats, try their hand at take off and landing of a Boeing 717 flight simulator on board. Computer monitors are mounted in the first class passenger windows displaying left and right views of the flight simulator. B-24D "Liberator" heavy bomber which features an onboard film giving visitors the feeling that they are riding along with the pilots. 1903 Wright Flyer replica Lockheed Martin F-22 Raptor cockpit replica A-6 Nose Section Bell P-39Q "Airacobra" Convair F-106B "Delta Dart" F-4E "Phantom II" F-104C "Starfighter" F-16 Nose Section F-18 High Alpha Research Vehicle "HARV" F-84F Thunderstreak Grumman-American Yankee Aircraft Hawker Siddeley Kestrel XV-6A KITFOX Model 4 Speedster Pershing II Missile Piper J-3 Cub Pitts Special Rutan VariEze homebuilt light aircraft Schleicher ASW 12 Glider Stearman N2S-3 Trainer UH-1M "Iroquois" Helicopter YF-16 "Fighting Falcon" Visitors enter through a room which simulates a manned launch to Mars, telling the story of a rendezvous with a Mars Transit Vehicle and arrival at the planet where doors open up into the gallery.
Apollo 12 Command Module, the Yankee Clipper Apollo Lunar Excursion Module Simulator, suspended by a huge gantry and used by astronauts at the Langley Research Center to practice landing on the lunar surface Viking Lander full-scale replica Gemini 10 hatch Mercury XIV spacecraft Sounding rockets similar to those launched at NASA's Wallops Flight Facility 90 miles north. Lunar Orbiter full-scale replica Rocks from Mars and the Moon Lunar Landing simulator Visitors can experience the hands-on space gallery, "Space Quest: Exploring the Moon, Mars & Beyond," presented by Langley Federal Credit Union; this gallery includes four different exhibits. This permanent exhibit focuses on the planets within our solar system. Within this exhibit there are planetary models. Saturn, Jupiter and Neptune hang high above the second-floor, nearly 30 feet high; these four models are the largest in the country to be displayed inside a science center. Jupiter, the largest of the models, weighs more than 750 pounds, has a diameter of 10 feet, hangs 22 feet in the air.
Saturn is eight-and-a-half feet in diameter and weighs 450 pounds, with an additional 495 pounds of rings encircling the planet's body. Hanging more than 30 feet high, Saturn floats above Uranus and Neptune which each weigh around 65 pounds; the models are composed of heavy-duty Styrofoam, painted to resemble each of the planets. The Solar System is completed with smaller models of Earth, Mars and Mercury mounted at the visitor's level. Created to be a scale model system, Earth is about the size as a soccer ball and Mercury measures up to a mere baseball. Out of 447 IMAX theaters worldwide and 256 in the US, the Riverside IMAX 3D Theater, is the first institutional theater in the world to have an IMAX Digital. Air Power Park Buckroe Beach Carousel List of aerospace museums Official website
In aerodynamics, wing loading is the total weight of an aircraft divided by the area of its wing. The stalling speed of an aircraft in straight, level flight is determined by its wing loading. An aircraft with a low wing loading has a larger wing area relative to its mass, as compared to an aircraft with a high wing loading; the faster an aircraft flies, the more lift can be produced by each unit of wing area, so a smaller wing can carry the same mass in level flight. Faster aircraft have higher wing loadings than slower aircraft; this increased wing loading increases takeoff and landing distances. A higher wing loading decreases maneuverability; the same constraints apply to winged biological organisms. Wing loading is a useful measure of the stalling speed of an aircraft. Wings generate lift owing to the motion of air around the wing. Larger wings move more air, so an aircraft with a large wing area relative to its mass will have a lower stalling speed. Therefore, an aircraft with lower wing loading will be able to land at a lower speed.
It will be able to turn at a greater rate. The lift force L on a wing of area A, traveling at true airspeed v is given by L = 1 2 ρ v 2 A C L, where ρ is the density of air and CL is the lift coefficient; the lift coefficient is a dimensionless number which depends on the wing cross-sectional profile and the angle of attack. At take-off or in steady flight, neither climbing nor diving, the lift force and the weight are equal. With L/A = Mg/A =WSg, where M is the aircraft mass, WS = M/A the wing loading and g the acceleration due to gravity, that equation gives the speed v through v 2 = 2 g W S ρ C L; as a consequence, aircraft with the same CL at takeoff under the same atmospheric conditions will have takeoff speeds proportional to W S. So if an aircraft's wing area is increased by 10% and nothing else is changed, the takeoff speed will fall by about 5%. If an aircraft designed to take off at 150 mph grows in weight during development by 40%, its takeoff speed increases to 150 1.4 = 177 mph. Some flyers rely on their muscle power to gain speed for takeoff over water.
Ground nesting and water birds have to be able to run or paddle at their takeoff speed before they can take off. The same is true for a hang glider pilot. For all these, a low WS is critical, whereas passerines and cliff dwelling birds can get airborne with higher wing loadings. To turn, an aircraft must roll in the direction of the turn. Turning flight hence causes a descent. To compensate, the lift force must be increased by increasing the angle of attack by use of up elevator deflection which increases drag. Turning can be described as'climbing around a circle' so the increase in wing angle of attack creates more drag; the tighter the turn radius attempted, the more drag induced, this requires that power be added to overcome the drag. The maximum rate of turn possible for a given aircraft design is limited by its wing size and available engine power: the maximum turn the aircraft can achieve and hold is its sustained turn performance; as the bank angle increases so does the g-force applied to the aircraft, this having the effect of increasing the wing loading and the stalling speed.
This effect is experienced during level pitching maneuvers. As stalling is due to wing loading and maximum lift coefficient at a given altitude and speed, this limits the turning radius due to maximum load factor. At Mach 0.85 and 0.7 lift coefficient, a wing loading of 50 lb/sq ft can reach a structural limit of 7.33 g up to 15,000 feet and decreases to 2.3 g at 40,000 feet while with a wing loading of 100 lb/sq ft the load factor is twice smaller and reach 1g at 40,000 feet. Aircraft with low wing loadings tend to have superior sustained turn performance because they can generate more lift for a given quantity of engine thrust; the immediate bank angle an aircraft can achieve before drag bleeds off airspeed is known as its instantaneous turn performance. An aircraft with a small loaded wing may have superior instantaneous turn performance, but poor sustained turn performance: it reacts to control input, but its ability to sustain a tight turn is limited. A classic example is the F-104 Starfighter, which has a small wing and high 723 kg/m2 wing loading.
At the opposite end of the spectrum was the large Convair B-36: its large wings resulted in a low 269 kg/m2 wing loading that could make it sustain tighter turns at high altitude than contemporary jet fighters, while the later Hawker Hunter had a similar wing loading of 344 kg/m2. The Boeing 367-80 airliner prototype could be rolled at low altitudes with a wing loading of 387 kg/m2 at maximum weight. Like any body in circular motion, an aircraft, fast and strong enough to maintain level flight at speed v in a circle of radius R accelerates towards the center
A variable-sweep wing, colloquially known as a "swing wing", is an airplane wing, or set of wings, that may be swept back and returned to its original position during flight. It allows the aircraft's shape to be modified in flight, is therefore an example of a variable-geometry aircraft. A swept wing is more suitable for high speeds, while an unswept wing is suitable for lower speeds, allowing the aircraft to carry more fuel and/or payload, as well as improving field performance. A variable-sweep wing allows a pilot to select the correct wing configuration for the plane's intended speed; the variable-sweep wing is most useful for those aircraft that are expected to function at both low and high speed, for this reason it has been used in military aircraft. A number of successful and experimental designs were introduced from the 1940s into the 1970s; this is another form of variable geometry, although it is not called such. The 1931 Westland-Hill Pterodactyl IV was a tailless design whose swept wings could vary their sweep through a small angle during flight.
This allowed longitudinal trim in the absence of a separate horizontal stabiliser. Experimental aircraft were built to study the effects of a simple swept wing; the first of these was the Messerschmitt Me P. 1101. World War II in Europe ended a few weeks before its scheduled first flight; the P.1101 was taken to the United States for study at Bell Aircraft, but because of missing documentation and structural damage, Bell decided against completing it. Instead, a close copy was constructed; as the position of the lift relative to the cg changes with wing sweep, the Bell X-5 wing translated forward as sweep increased to prevent excessive stability. A more practical solution for subsequent swing-wing designs was the outboard pivot, or rotation-only concept pioneered by Barnes Wallis around 1954; the detailed implementation of the concept was done by the NASA Langley Laboratory team of Alford and Barnes Wallis. In 1949, British engineer Barnes Wallis started work on variable geometry to maximise the economy of supersonic flight.
His first study, for the military, was the Wild Goose project. He studied the Swallow, intended to achieve a return flight from Europe to Australia in 10 hours, it had a blended wing tailless design and he tested several models including a six-foot scale model at speeds of up to Mach 2 in the 1950s, but in 1957, government backing was withdrawn for many aeronautical research and development programs, including Wallis' work. Wallis and his team presented their work to the Americans seeking a grant to continue their studies but none was forthcoming. In March 1949, British engineer L. E. Baynes designed a supersonic variable-sweep wing fighter, he lodged patent applications in Britain, in May 1956 was granted US Patent 2,744,698 for "High Speed Aircraft Wing and Tail Surfaces Having Variable Sweep-back". In February 1951 he applied for another patent for a supersonic variable-sweep wing and tail fighter; the design was built and wind tunnel tests were completed, but due to budget constraints at the time, the government did not provide financial backing.
A variable-sweep wing was tried on the Grumman F10F Jaguar in 1952. The F10F never entered service; the idea was again revived in the early 1960s as a way to reconcile ever-growing aircraft weights with the need to provide reasonable takeoff and landing performance. The United States adopted this configuration for the TFX program, which emerged as the General Dynamics F-111, the first production variable-sweep wing aircraft. Similar requirements in the Soviet Union led TsAGI, the Soviet aerodynamics bureau, to study variable geometry. TsAGI evolved two distinct designs, differing in the distance between the wing pivots. A wider spacing not only reduced the negative aerodynamic effects of changing wing sweep, but provided a larger fixed wing section which could be used for landing gear or stores pylons; this could, in fact, be adapted to more-or-less existing airframes, which the Soviets soon did, with the Sukhoi Su-17. The limitation of the wide spacing, was that it reduced the benefits of variable geometry as much as it reduced their technical difficulties.
For the new, "clean-sheet" Soviet designs, TsAGI devised a more narrowly spaced arrangement similar to that of the F-111. This design was used for the MiG-23 fighter and the Sukhoi Su-24 interceptor, which flew in prototype forms at the end of the 1960s, entering service in the early 1970s; as of 2014 more than 100 Tupolev Tu-22M strategic bombers are in use. In the aftermath of the cancellation of the TSR-2, the British had started a project with the French for the Anglo-French Variable Geometry aircraft; when French commitment was curtailed, the British sought a second partner in the F-104
An air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are powered by one or more rocket motors solid fueled but sometimes liquid fueled. Ramjet engines, as used on the Meteor are emerging as propulsion that will enable future medium-range missiles to maintain higher average speed across their engagement envelope. Air-to-air missiles are broadly put in two groups; those designed to engage opposing aircraft at ranges of less than 30 km are known as short-range or "within visual range" missiles and are sometimes called "dogfight" missiles because they are designed to optimize their agility rather than range. Most use are called heat-seeking missiles. In contrast, medium- or long-range missiles, which both fall under the category of beyond visual range missiles, tend to rely upon radar guidance, of which there are many forms; some modern ones use inertial guidance and/or "mid-course updates" to get the missile close enough to use an active homing sensor.
The air-to-air missile grew out of the unguided air-to-air rockets used during the First World War. Le Prieur rockets were sometimes attached to the struts of biplanes and fired electrically against observation balloons, by such early pilots as Albert Ball and A. M. Walters. Facing the Allied air superiority, Germany in World War II invested limited effort into missile research, leading to the deployment of the R4M unguided rocket and the development of various guided missile prototypes such as the Ruhrstahl X-4. Post-war research led the Royal Air Force to introduce Fairey Fireflash into service in 1955 but their results were unsuccessful; the US Navy and US Air Force began equipping guided missiles in 1956, deploying the USAF's AIM-4 Falcon and the USN's AIM-7 Sparrow and AIM-9 Sidewinder. The Soviet Air Force introduced its K-5 into service in 1957; as missile systems have continued to advance, modern air warfare consists entirely of missile firing. The use of Beyond Visual Range combat became so pervasive in the US that early F-4 variants were armed only with missiles in the 1960s.
High casualty rates during the Vietnam War caused the US to reintroduce autocannon and traditional dogfighting tactics but the missile remains the primary weapon in air combat. In the Falklands War British Harriers, using AIM-9L missiles were able to defeat faster Argentinian opponents. Since the late 20th century all-aspect heat-seeking designs can lock-on to a target from various angles, not just from behind, where the heat signature from the engines is strongest. Other types rely on radar guidance. A conventional explosive blast warhead, fragmentation warhead, or continuous rod warhead is used in the attempt to disable or destroy the target aircraft. Warheads are detonated by a proximity fuze or by an impact fuze if it scores a direct hit. Less nuclear warheads have been mounted on a small number of air-to-air missile types although these are not known to have been used in combat. Guided missiles operate by detecting their target, "homing" in on the target on a collision course. Although the missile may use radar or infra-red guidance to home on the target, the launching aircraft may detect and track the target before launch by other means.
Infra-red guided missiles can be "slaved" to an attack radar in order to find the target and radar-guided missiles can be launched at targets detected visually or via an infra-red search and track system, although they may require the attack radar to illuminate the target during part or all of the missile interception itself. Radar guidance is used for medium- or long-range missiles, where the infra-red signature of the target would be too faint for an infra-red detector to track. There are three major types of radar-guided missile – active, semi-active, passive. Radar-guided missiles can be countered by rapid maneuvering, deploying chaff or using electronic counter-measures. Active radar -guided missiles carry their own radar system to detect and track their target. However, the size of the radar antenna is limited by the small diameter of missiles, limiting its range which means such missiles are launched at a predicted future location of the target relying on separate guidance systems such as Global Positioning System, inertial guidance, or a mid-course update from either the launching aircraft or other system that can communicate with the missile to get the missile close to the target.
At a predetermined point the missile's radar system is activated, the missile homes in on the target. If the range from the attacking aircraft to the target is within the range of the missile's radar system, the missile can "go active" upon launch; the great advantage of an active radar homing system is that it enables a "fire-and-forget" mode of attack, where the attacking aircraft is free to pursue other targets or escape the area after launching the missile. Semi-active radar homing guided missiles are more common, they function by detecting radar energy reflected from the target. The radar energy is emitted from the launching aircraft's own radar system. However, this means that the launch aircraft has to maintain a "lock" on the target (keep illuminating the target aircraft w