126-864: The Teen Series is a popular name for a group of American combat aircraft. The name stems from a series of American supersonic jet fighters built for the United States Air Force and the United States Navy during the late 20th century. The designations system was the 1962 United States Tri-Service aircraft designation system , which reset the F-# sequence. The term typically includes the Grumman F-14 Tomcat , McDonnell Douglas F-15 Eagle , General Dynamics F-16 Fighting Falcon , and McDonnell Douglas F/A-18 Hornet . Unsuccessful experimental and prototype fighters assigned numbers in
252-470: A fractal surface, such as rocks or soil, and are used by navigation radars. A radar beam follows a linear path in vacuum but follows a somewhat curved path in atmosphere due to variation in the refractive index of air, which is called the radar horizon . Even when the beam is emitted parallel to the ground, the beam rises above the ground as the curvature of the Earth sinks below the horizon. Furthermore,
378-403: A receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II . A key development was the cavity magnetron in
504-424: A transmitter that emits radio waves known as radar signals in predetermined directions. When these signals contact an object they are usually reflected or scattered in many directions, although some of them will be absorbed and penetrate into the target. Radar signals are reflected especially well by materials of considerable electrical conductivity —such as most metals, seawater , and wet ground. This makes
630-584: A by now mediocre performance. The first Eindecker victory came on 1 July 1915, when Leutnant Kurt Wintgens , of Feldflieger Abteilung 6 on the Western Front, downed a Morane-Saulnier Type L. His was one of five Fokker M.5 K/MG prototypes for the Eindecker , and was armed with a synchronized aviation version of the Parabellum MG14 machine gun. The success of the Eindecker kicked off
756-470: A cadre of exceptional pilots. In the United Kingdom, at the behest of Neville Chamberlain (more famous for his 'peace in our time' speech), the entire British aviation industry was retooled, allowing it to change quickly from fabric covered metal framed biplanes to cantilever stressed skin monoplanes in time for the war with Germany, a process that France attempted to emulate, but too late to counter
882-465: A combatant's efforts to gain air superiority hinges on several factors including the skill of its pilots, the tactical soundness of its doctrine for deploying its fighters, and the numbers and performance of those fighters. Many modern fighter aircraft also have secondary capabilities such as ground attack and some types, such as fighter-bombers , are designed from the outset for dual roles. Other fighter designs are highly specialized while still filling
1008-435: A competitive cycle of improvement among the combatants, both sides striving to build ever more capable single-seat fighters. The Albatros D.I and Sopwith Pup of 1916 set the classic pattern followed by fighters for about twenty years. Most were biplanes and only rarely monoplanes or triplanes . The strong box structure of the biplane provided a rigid wing that allowed the accurate control essential for dogfighting. They had
1134-482: A different dielectric constant or diamagnetic constant from the first, the waves will reflect or scatter from the boundary between the materials. This means that a solid object in air or in a vacuum , or a significant change in atomic density between the object and what is surrounding it, will usually scatter radar (radio) waves from its surface. This is particularly true for electrically conductive materials such as metal and carbon fibre, making radar well-suited to
1260-443: A difficult deflection shot. The first step in finding a real solution was to mount the weapon on the aircraft, but the propeller remained a problem since the best direction to shoot is straight ahead. Numerous solutions were tried. A second crew member behind the pilot could aim and fire a swivel-mounted machine gun at enemy airplanes; however, this limited the area of coverage chiefly to the rear hemisphere, and effective coordination of
1386-552: A form that would replace all others in the 1930s. As collective combat experience grew, the more successful pilots such as Oswald Boelcke , Max Immelmann , and Edward Mannock developed innovative tactical formations and maneuvers to enhance their air units' combat effectiveness. Allied and – before 1918 – German pilots of World War I were not equipped with parachutes , so in-flight fires or structural failures were often fatal. Parachutes were well-developed by 1918 having previously been used by balloonists, and were adopted by
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#17327809099991512-540: A full radar system, that he called a telemobiloscope . It operated on a 50 cm wavelength and the pulsed radar signal was created via a spark-gap. His system already used the classic antenna setup of horn antenna with parabolic reflector and was presented to German military officials in practical tests in Cologne and Rotterdam harbour but was rejected. In 1915, Robert Watson-Watt used radio technology to provide advance warning of thunderstorms to airmen and during
1638-664: A great deal of ground-attack work. In World War II, the USAAF and RAF often favored fighters over dedicated light bombers or dive bombers , and types such as the Republic P-47 Thunderbolt and Hawker Hurricane that were no longer competitive as aerial combat fighters were relegated to ground attack. Several aircraft, such as the F-111 and F-117, have received fighter designations though they had no fighter capability due to political or other reasons. The F-111B variant
1764-431: A number of twin-engine fighters were built; however they were found to be outmatched against single-engine fighters and were relegated to other tasks, such as night fighters equipped with radar sets. By the end of the war, turbojet engines were replacing piston engines as the means of propulsion, further increasing aircraft speed. Since the weight of the turbojet engine was far less than a piston engine, having two engines
1890-550: A part of military nomenclature, a letter is often assigned to various types of aircraft to indicate their use, along with a number to indicate the specific aircraft. The letters used to designate a fighter differ in various countries. In the English-speaking world, "F" is often now used to indicate a fighter (e.g. Lockheed Martin F-35 Lightning II or Supermarine Spitfire F.22 ), though "P" used to be used in
2016-749: A physics instructor at the Imperial Russian Navy school in Kronstadt , developed an apparatus using a coherer tube for detecting distant lightning strikes. The next year, he added a spark-gap transmitter . In 1897, while testing this equipment for communicating between two ships in the Baltic Sea , he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, but he did nothing more with this observation. The German inventor Christian Hülsmeyer
2142-498: A proposal for further intensive research on radio-echo signals from moving targets to take place at NRL, where Taylor and Young were based at the time. Similarly, in the UK, L. S. Alder took out a secret provisional patent for Naval radar in 1928. W.A.S. Butement and P. E. Pollard developed a breadboard test unit, operating at 50 cm (600 MHz) and using pulsed modulation which gave successful laboratory results. In January 1931,
2268-732: A pulsed system, and the first such elementary apparatus was demonstrated in December 1934 by the American Robert M. Page , working at the Naval Research Laboratory . The following year, the United States Army successfully tested a primitive surface-to-surface radar to aim coastal battery searchlights at night. This design was followed by a pulsed system demonstrated in May 1935 by Rudolf Kühnhold and
2394-638: A range of specialized aircraft types. Some of the most expensive fighters such as the US Grumman F-14 Tomcat , McDonnell Douglas F-15 Eagle , Lockheed Martin F-22 Raptor and Russian Sukhoi Su-27 were employed as all-weather interceptors as well as air superiority fighter aircraft, while commonly developing air-to-ground roles late in their careers. An interceptor is generally an aircraft intended to target (or intercept) bombers and so often trades maneuverability for climb rate. As
2520-442: A rescue. For similar reasons, objects intended to avoid detection will not have inside corners or surfaces and edges perpendicular to likely detection directions, which leads to "odd" looking stealth aircraft . These precautions do not totally eliminate reflection because of diffraction , especially at longer wavelengths. Half wavelength long wires or strips of conducting material, such as chaff , are very reflective but do not direct
2646-742: A result, during the early months of these campaigns, Axis air forces destroyed large numbers of Red Air Force aircraft on the ground and in one-sided dogfights. In the later stages on the Eastern Front, Soviet training and leadership improved, as did their equipment. By 1942 Soviet designs such as the Yakovlev Yak-9 and Lavochkin La-5 had performance comparable to the German Bf 109 and Focke-Wulf Fw 190 . Also, significant numbers of British, and later U.S., fighter aircraft were supplied to aid
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#17327809099992772-643: A separate (and vulnerable) radiator, but had increased drag. Inline engines often had a better power-to-weight ratio . Some air forces experimented with " heavy fighters " (called "destroyers" by the Germans). These were larger, usually twin-engined aircraft, sometimes adaptations of light or medium bomber types. Such designs typically had greater internal fuel capacity (thus longer range) and heavier armament than their single-engine counterparts. In combat, they proved vulnerable to more agile single-engine fighters. The primary driver of fighter innovation, right up to
2898-420: A single operator, who flew the aircraft and also controlled its armament. They were armed with one or two Maxim or Vickers machine guns, which were easier to synchronize than other types, firing through the propeller arc. Gun breeches were in front of the pilot, with obvious implications in case of accidents, but jams could be cleared in flight, while aiming was simplified. The use of metal aircraft structures
3024-677: A system might do, Wilkins recalled the earlier report about aircraft causing radio interference. This revelation led to the Daventry Experiment of 26 February 1935, using a powerful BBC shortwave transmitter as the source and their GPO receiver setup in a field while a bomber flew around the site. When the plane was clearly detected, Hugh Dowding , the Air Member for Supply and Research , was very impressed with their system's potential and funds were immediately provided for further operational development. Watson-Watt's team patented
3150-514: A wide region and direct fighter aircraft towards targets. Marine radars are used to measure the bearing and distance of ships to prevent collision with other ships, to navigate, and to fix their position at sea when within range of shore or other fixed references such as islands, buoys, and lightships. In port or in harbour, vessel traffic service radar systems are used to monitor and regulate ship movements in busy waters. Meteorologists use radar to monitor precipitation and wind. It has become
3276-843: A writeup on the apparatus was entered in the Inventions Book maintained by the Royal Engineers. This is the first official record in Great Britain of the technology that was used in coastal defence and was incorporated into Chain Home as Chain Home (low) . Before the Second World War , researchers in the United Kingdom, France , Germany , Italy , Japan , the Netherlands , the Soviet Union , and
3402-402: Is a fast, heavily armed and long-range type, able to act as an escort fighter protecting bombers , to carry out offensive sorties of its own as a penetration fighter and maintain standing patrols at significant distance from its home base. Bombers are vulnerable due to their low speed, large size and poor maneuvrability. The escort fighter was developed during World War II to come between
3528-452: Is a simplification for transmission in a vacuum without interference. The propagation factor accounts for the effects of multipath and shadowing and depends on the details of the environment. In a real-world situation, pathloss effects are also considered. Frequency shift is caused by motion that changes the number of wavelengths between the reflector and the radar. This can degrade or enhance radar performance depending upon how it affects
3654-549: Is able to defend itself while conducting attack sorties. The word "fighter" was first used to describe a two-seat aircraft carrying a machine gun (mounted on a pedestal) and its operator as well as the pilot . Although the term was coined in the United Kingdom, the first examples were the French Voisin pushers beginning in 1910, and a Voisin III would be the first to shoot down another aircraft, on 5 October 1914. However at
3780-451: Is as follows, where F D {\displaystyle F_{D}} is Doppler frequency, F T {\displaystyle F_{T}} is transmit frequency, V R {\displaystyle V_{R}} is radial velocity, and C {\displaystyle C} is the speed of light: Passive radar is applicable to electronic countermeasures and radio astronomy as follows: Only
3906-567: Is intended. Radar relies on its own transmissions rather than light from the Sun or the Moon, or from electromagnetic waves emitted by the target objects themselves, such as infrared radiation (heat). This process of directing artificial radio waves towards objects is called illumination , although radio waves are invisible to the human eye as well as optical cameras. If electromagnetic waves travelling through one material meet another material, having
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4032-623: Is known as an interceptor . Recognized classes of fighter include: Of these, the Fighter-bomber , reconnaissance fighter and strike fighter classes are dual-role, possessing qualities of the fighter alongside some other battlefield role. Some fighter designs may be developed in variants performing other roles entirely, such as ground attack or unarmed reconnaissance . This may be for political or national security reasons, for advertising purposes, or other reasons. The Sopwith Camel and other "fighting scouts" of World War I performed
4158-417: Is the range. This yields: This shows that the received power declines as the fourth power of the range, which means that the received power from distant targets is relatively very small. Additional filtering and pulse integration modifies the radar equation slightly for pulse-Doppler radar performance , which can be used to increase detection range and reduce transmit power. The equation above with F = 1
4284-439: Is to establish air superiority of the battlespace . Domination of the airspace above a battlefield permits bombers and attack aircraft to engage in tactical and strategic bombing of enemy targets, and helps prevent the enemy from doing the same. The key performance features of a fighter include not only its firepower but also its high speed and maneuverability relative to the target aircraft. The success or failure of
4410-562: The Combined Bomber Offensive . Unescorted Consolidated B-24 Liberators and Boeing B-17 Flying Fortress bombers, however, proved unable to fend off German interceptors (primarily Bf 109s and Fw 190s). With the later arrival of long range fighters, particularly the North American P-51 Mustang , American fighters were able to escort far into Germany on daylight raids and by ranging ahead attrited
4536-585: The Junkers D.I , made with corrugated duralumin , all based on his experience in creating the pioneering Junkers J 1 all-metal airframe technology demonstration aircraft of late 1915. While Fokker would pursue steel tube fuselages with wooden wings until the late 1930s, and Junkers would focus on corrugated sheet metal, Dornier was the first to build a fighter (the Dornier-Zeppelin D.I ) made with pre-stressed sheet aluminum and having cantilevered wings,
4662-628: The Nyquist frequency , since the returned frequency otherwise cannot be distinguished from shifting of a harmonic frequency above or below, thus requiring: Or when substituting with F D {\displaystyle F_{D}} : As an example, a Doppler weather radar with a pulse rate of 2 kHz and transmit frequency of 1 GHz can reliably measure weather speed up to at most 150 m/s (340 mph), thus cannot reliably determine radial velocity of aircraft moving 1,000 m/s (2,200 mph). In all electromagnetic radiation ,
4788-510: The RAF and the USAAF against German industry intended to wear down the Luftwaffe. Axis fighter aircraft focused on defending against Allied bombers while Allied fighters' main role was as bomber escorts. The RAF raided German cities at night, and both sides developed radar-equipped night fighters for these battles. The Americans, in contrast, flew daylight bombing raids into Germany delivering
4914-669: The RAF's Pathfinder . The information provided by radar includes the bearing and range (and therefore position) of the object from the radar scanner. It is thus used in many different fields where the need for such positioning is crucial. The first use of radar was for military purposes: to locate air, ground and sea targets. This evolved in the civilian field into applications for aircraft, ships, and automobiles. In aviation , aircraft can be equipped with radar devices that warn of aircraft or other obstacles in or approaching their path, display weather information, and give accurate altitude readings. The first commercial device fitted to aircraft
5040-588: The Sopwith Tabloid and Bristol Scout . The French and the Germans didn't have an equivalent as they used two seaters for reconnaissance, such as the Morane-Saulnier L , but would later modify pre-war racing aircraft into armed single seaters. It was quickly found that these were of little use since the pilot couldn't record what he saw while also flying, while military leaders usually ignored what
5166-792: The Stangensteuerung in German, for "pushrod control system") devised by the engineers of Anthony Fokker 's firm was the first system to enter service. It would usher in what the British called the " Fokker scourge " and a period of air superiority for the German forces, making the Fokker Eindecker monoplane a feared name over the Western Front , despite its being an adaptation of an obsolete pre-war French Morane-Saulnier racing airplane, with poor flight characteristics and
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5292-1209: The United Kingdom , which allowed the creation of relatively small systems with sub-meter resolution. The term RADAR was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term radar has since entered English and other languages as an anacronym , a common noun, losing all capitalization . The modern uses of radar are highly diverse, including air and terrestrial traffic control, radar astronomy , air-defense systems , anti-missile systems , marine radars to locate landmarks and other ships, aircraft anti-collision systems, ocean surveillance systems, outer space surveillance and rendezvous systems, meteorological precipitation monitoring, radar remote sensing , altimetry and flight control systems , guided missile target locating systems, self-driving cars , and ground-penetrating radar for geological observations. Modern high tech radar systems use digital signal processing and machine learning and are capable of extracting useful information from very high noise levels. Other systems which are similar to radar make use of other parts of
5418-440: The electromagnetic spectrum . One example is lidar , which uses predominantly infrared light from lasers rather than radio waves. With the emergence of driverless vehicles, radar is expected to assist the automated platform to monitor its environment, thus preventing unwanted incidents. As early as 1886, German physicist Heinrich Hertz showed that radio waves could be reflected from solid objects. In 1895, Alexander Popov ,
5544-407: The reflective surfaces . A corner reflector consists of three flat surfaces meeting like the inside corner of a cube. The structure will reflect waves entering its opening directly back to the source. They are commonly used as radar reflectors to make otherwise difficult-to-detect objects easier to detect. Corner reflectors on boats, for example, make them more detectable to avoid collision or during
5670-534: The "new boy" Arnold Frederic Wilkins to conduct an extensive review of available shortwave units. Wilkins would select a General Post Office model after noting its manual's description of a "fading" effect (the common term for interference at the time) when aircraft flew overhead. By placing a transmitter and receiver on opposite sides of the Potomac River in 1922, U.S. Navy researchers A. Hoyt Taylor and Leo C. Young discovered that ships passing through
5796-413: The 1920s went on to lead the U.K. research establishment to make many advances using radio techniques, including the probing of the ionosphere and the detection of lightning at long distances. Through his lightning experiments, Watson-Watt became an expert on the use of radio direction finding before turning his inquiry to shortwave transmission. Requiring a suitable receiver for such studies, he told
5922-668: The British Royal Flying Corps and Royal Air Force referred to them as " scouts " until the early 1920s, while the U.S. Army called them "pursuit" aircraft until the late 1940s (using the designation P, as in Curtiss P-40 Warhawk , Republic P-47 Thunderbolt and Bell P-63 Kingcobra ). The UK changed to calling them fighters in the 1920s , while the US Army did so in the 1940s. A short-range fighter designed to defend against incoming enemy aircraft
6048-639: The British, the Americans, the Spanish (in the Spanish civil war) and the Germans. Given limited budgets, air forces were conservative in aircraft design, and biplanes remained popular with pilots for their agility, and remained in service long after they ceased to be competitive. Designs such as the Gloster Gladiator , Fiat CR.42 Falco , and Polikarpov I-15 were common even in the late 1930s, and many were still in service as late as 1942. Up until
6174-614: The European battlefield, played a crucial role in the eventual defeat of the Axis, which Reichmarshal Hermann Göring , commander of the German Luftwaffe summed up when he said: "When I saw Mustangs over Berlin, I knew the jig was up." Radar Radar is a system that uses radio waves to determine the distance ( ranging ), direction ( azimuth and elevation angles ), and radial velocity of objects relative to
6300-483: The German flying services during the course of that year. The well known and feared Manfred von Richthofen , the "Red Baron", was wearing one when he was killed, but the allied command continued to oppose their use on various grounds. In April 1917, during a brief period of German aerial supremacy a British pilot's average life expectancy was calculated to average 93 flying hours, or about three weeks of active service. More than 50,000 airmen from both sides died during
6426-618: The German invasion. The period of improving the same biplane design over and over was now coming to an end, and the Hawker Hurricane and Supermarine Spitfire started to supplant the Gloster Gladiator and Hawker Fury biplanes but many biplanes remained in front-line service well past the start of World War II. While not a combatant in Spain, they too absorbed many of the lessons in time to use them. The Spanish Civil War also provided an opportunity for updating fighter tactics. One of
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#17327809099996552-756: The Italians developed several monoplanes such as the Fiat G.50 Freccia , but being short on funds, were forced to continue operating obsolete Fiat CR.42 Falco biplanes. From the early 1930s the Japanese were at war against both the Chinese Nationalists and the Russians in China, and used the experience to improve both training and aircraft, replacing biplanes with modern cantilever monoplanes and creating
6678-968: The Japanese Nakajima Ki-27 , Nakajima Ki-43 and Mitsubishi A6M Zero and the Italian Fiat G.50 Freccia and Macchi MC.200 . In contrast, designers in the United Kingdom, Germany, the Soviet Union, and the United States believed that the increased speed of fighter aircraft would create g -forces unbearable to pilots who attempted maneuvering dogfights typical of the First World War, and their fighters were instead optimized for speed and firepower. In practice, while light, highly maneuverable aircraft did possess some advantages in fighter-versus-fighter combat, those could usually be overcome by sound tactical doctrine, and
6804-613: The Luftwaffe to establish control of the skies over Western Europe. By the time of Operation Overlord in June 1944, the Allies had gained near complete air superiority over the Western Front. This cleared the way both for intensified strategic bombing of German cities and industries, and for the tactical bombing of battlefield targets. With the Luftwaffe largely cleared from the skies, Allied fighters increasingly served as ground attack aircraft. Allied fighters, by gaining air superiority over
6930-662: The Luftwaffe, and while the Luftwaffe maintained a qualitative edge over the Red Air Force for much of the war, the increasing numbers and efficacy of the Soviet Air Force were critical to the Red Army's efforts at turning back and eventually annihilating the Wehrmacht . Meanwhile, air combat on the Western Front had a much different character. Much of this combat focused on the strategic bombing campaigns of
7056-555: The Soviet Polikarpov I-16 . The later German design was earlier in its design cycle, and had more room for development and the lessons learned led to greatly improved models in World War II. The Russians failed to keep up and despite newer models coming into service, I-16s remaining the most common Soviet front-line fighter into 1942 despite being outclassed by the improved Bf 109s in World War II. For their part,
7182-598: The Soviet war effort as part of Lend-Lease , with the Bell P-39 Airacobra proving particularly effective in the lower-altitude combat typical of the Eastern Front. The Soviets were also helped indirectly by the American and British bombing campaigns, which forced the Luftwaffe to shift many of its fighters away from the Eastern Front in defense against these raids. The Soviets increasingly were able to challenge
7308-605: The US for pursuit (e.g. Curtiss P-40 Warhawk ), a translation of the French "C" ( Dewoitine D.520 C.1 ) for Chasseur while in Russia "I" was used for Istrebitel , or exterminator ( Polikarpov I-16 ). As fighter types have proliferated, the air superiority fighter emerged as a specific role at the pinnacle of speed, maneuverability, and air-to-air weapon systems – able to hold its own against all other fighters and establish its dominance in
7434-529: The United States, Russia, India and China. The first step was to find ways to reduce the aircraft's reflectivity to radar waves by burying the engines, eliminating sharp corners and diverting any reflections away from the radar sets of opposing forces. Various materials were found to absorb the energy from radar waves, and were incorporated into special finishes that have since found widespread application. Composite structures have become widespread, including major structural components, and have helped to counterbalance
7560-724: The United States, independently and in great secrecy, developed technologies that led to the modern version of radar. Australia, Canada, New Zealand, and South Africa followed prewar Great Britain's radar development, Hungary and Sweden generated its radar technology during the war. In France in 1934, following systematic studies on the split-anode magnetron , the research branch of the Compagnie générale de la télégraphie sans fil (CSF) headed by Maurice Ponte with Henri Gutton, Sylvain Berline and M. Hugon, began developing an obstacle-locating radio apparatus, aspects of which were installed on
7686-409: The advantages of fighting above Britain's home territory allowed the RAF to deny Germany air superiority, saving the UK from possible German invasion and dealing the Axis a major defeat early in the Second World War. On the Eastern Front , Soviet fighter forces were overwhelmed during the opening phases of Operation Barbarossa . This was a result of the tactical surprise at the outset of the campaign,
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#17327809099997812-486: The arrest of Oshchepkov and his subsequent gulag sentence. In total, only 607 Redut stations were produced during the war. The first Russian airborne radar, Gneiss-2 , entered into service in June 1943 on Pe-2 dive bombers. More than 230 Gneiss-2 stations were produced by the end of 1944. The French and Soviet systems, however, featured continuous-wave operation that did not provide the full performance ultimately synonymous with modern radar systems. Full radar evolved as
7938-433: The basis for an effective "fighter" in the modern sense of the word. It was based on small fast aircraft developed before the war for air racing such with the Gordon Bennett Cup and Schneider Trophy . The military scout airplane was not expected to carry serious armament, but rather to rely on speed to "scout" a location, and return quickly to report, making it a flying horse. British scout aircraft, in this sense, included
8064-444: The battlefield. Early fighters were very small and lightly armed by later standards, and most were biplanes built with a wooden frame covered with fabric, and a maximum airspeed of about 100 mph (160 km/h). A successful German biplane, the Albatross, however, was built with a plywood shell, rather than fabric, which created a stronger, faster airplane. As control of the airspace over armies became increasingly important, all of
8190-428: The beam path caused the received signal to fade in and out. Taylor submitted a report, suggesting that this phenomenon might be used to detect the presence of ships in low visibility, but the Navy did not immediately continue the work. Eight years later, Lawrence A. Hyland at the Naval Research Laboratory (NRL) observed similar fading effects from passing aircraft; this revelation led to a patent application as well as
8316-414: The bombers and enemy attackers as a protective shield. The primary requirement was for long range, with several heavy fighters given the role. However they too proved unwieldy and vulnerable, so as the war progressed techniques such as drop tanks were developed to extend the range of more nimble conventional fighters. The penetration fighter is typically also fitted for the ground-attack role, and so
8442-539: The defense budgets of modern armed forces. The global combat aircraft market was worth $ 45.75 billion in 2017 and is projected by Frost & Sullivan at $ 47.2 billion in 2026: 35% modernization programs and 65% aircraft purchases, dominated by the Lockheed Martin F-35 with 3,000 deliveries over 20 years. A fighter aircraft is primarily designed for air-to-air combat . A given type may be designed for specific combat conditions, and in some cases for additional roles such as air-to-ground fighting. Historically
8568-550: The design approach of the Italians and Japanese made their fighters ill-suited as interceptors or attack aircraft. During the invasion of Poland and the Battle of France , Luftwaffe fighters—primarily the Messerschmitt Bf 109 —held air superiority, and the Luftwaffe played a major role in German victories in these campaigns. During the Battle of Britain , however, British Hurricanes and Spitfires proved roughly equal to Luftwaffe fighters. Additionally Britain's radar-based Dowding system directing fighters onto German attacks and
8694-408: The detection of aircraft and ships. Radar absorbing material , containing resistive and sometimes magnetic substances, is used on military vehicles to reduce radar reflection . This is the radio equivalent of painting something a dark colour so that it cannot be seen by the eye at night. Radar waves scatter in a variety of ways depending on the size (wavelength) of the radio wave and the shape of
8820-421: The detection process. As an example, moving target indication can interact with Doppler to produce signal cancellation at certain radial velocities, which degrades performance. Sea-based radar systems, semi-active radar homing , active radar homing , weather radar , military aircraft, and radar astronomy rely on the Doppler effect to enhance performance. This produces information about target velocity during
8946-411: The detection process. This also allows small objects to be detected in an environment containing much larger nearby slow moving objects. Doppler shift depends upon whether the radar configuration is active or passive. Active radar transmits a signal that is reflected back to the receiver. Passive radar depends upon the object sending a signal to the receiver. The Doppler frequency shift for active radar
9072-626: The device in patent GB593017. Development of radar greatly expanded on 1 September 1936, when Watson-Watt became superintendent of a new establishment under the British Air Ministry , Bawdsey Research Station located in Bawdsey Manor , near Felixstowe, Suffolk. Work there resulted in the design and installation of aircraft detection and tracking stations called " Chain Home " along the East and South coasts of England in time for
9198-522: The early 1960s since both were believed unusable at the speeds being attained, however the Vietnam War showed that guns still had a role to play, and most fighters built since then are fitted with cannon (typically between 20 and 30 mm (0.79 and 1.18 in) in caliber) in addition to missiles. Most modern combat aircraft can carry at least a pair of air-to-air missiles. In the 1970s, turbofans replaced turbojets, improving fuel economy enough that
9324-538: The electric field is perpendicular to the direction of propagation, and the electric field direction is the polarization of the wave. For a transmitted radar signal, the polarization can be controlled to yield different effects. Radars use horizontal, vertical, linear, and circular polarization to detect different types of reflections. For example, circular polarization is used to minimize the interference caused by rain. Linear polarization returns usually indicate metal surfaces. Random polarization returns usually indicate
9450-473: The entire area in front of it, and then used one of Watson-Watt's own radio direction finders to determine the direction of the returned echoes. This fact meant CH transmitters had to be much more powerful and have better antennas than competing systems but allowed its rapid introduction using existing technologies. A key development was the cavity magnetron in the UK, which allowed the creation of relatively small systems with sub-meter resolution. Britain shared
9576-513: The fighter. Rifle-caliber .30 and .303 in (7.62 and 7.70 mm) calibre guns remained the norm, with larger weapons either being too heavy and cumbersome or deemed unnecessary against such lightly built aircraft. It was not considered unreasonable to use World War I-style armament to counter enemy fighters as there was insufficient air-to-air combat during most of the period to disprove this notion. The rotary engine , popular during World War I, quickly disappeared, its development having reached
9702-466: The firm GEMA [ de ] in Germany and then another in June 1935 by an Air Ministry team led by Robert Watson-Watt in Great Britain. In 1935, Watson-Watt was asked to judge recent reports of a German radio-based death ray and turned the request over to Wilkins. Wilkins returned a set of calculations demonstrating the system was basically impossible. When Watson-Watt then asked what such
9828-406: The guns were subjected). Shooting with this traditional arrangement was also easier because the guns shot directly ahead in the direction of the aircraft's flight, up to the limit of the guns range; unlike wing-mounted guns which to be effective required to be harmonised , that is, preset to shoot at an angle by ground crews so that their bullets would converge on a target area a set distance ahead of
9954-433: The innovations was the development of the " finger-four " formation by the German pilot Werner Mölders . Each fighter squadron (German: Staffel ) was divided into several flights ( Schwärme ) of four aircraft. Each Schwarm was divided into two Rotten , which was a pair of aircraft. Each Rotte was composed of a leader and a wingman. This flexible formation allowed the pilots to maintain greater situational awareness, and
10080-514: The interceptor. The equipment necessary for daytime flight is inadequate when flying at night or in poor visibility. The night fighter was developed during World War I with additional equipment to aid the pilot in flying straight, navigating and finding the target. From modified variants of the Royal Aircraft Factory B.E.2c in 1915, the night fighter has evolved into the highly capable all-weather fighter. The strategic fighter
10206-420: The last piston engine support aircraft could be replaced with jets, making multi-role combat aircraft possible. Honeycomb structures began to replace milled structures, and the first composite components began to appear on components subjected to little stress. With the steady improvements in computers, defensive systems have become increasingly efficient. To counter this, stealth technologies have been pursued by
10332-650: The leadership vacuum within the Soviet military left by the Great Purge , and the general inferiority of Soviet designs at the time, such as the obsolescent Polikarpov I-15 biplane and the I-16 . More modern Soviet designs, including the Mikoyan-Gurevich MiG-3 , LaGG-3 and Yakolev Yak-1 , had not yet arrived in numbers and in any case were still inferior to the Messerschmitt Bf 109 . As
10458-419: The main air superiority role, and these include the interceptor and, historically, the heavy fighter and night fighter . Since World War I, achieving and maintaining air superiority has been considered essential for victory in conventional warfare . Fighters continued to be developed throughout World War I, to deny enemy aircraft and dirigibles the ability to gather information by reconnaissance over
10584-471: The major powers developed fighters to support their military operations. Between the wars, wood was largely replaced in part or whole by metal tubing, and finally aluminum stressed skin structures (monocoque) began to predominate. By World War II , most fighters were all-metal monoplanes armed with batteries of machine guns or cannons and some were capable of speeds approaching 400 mph (640 km/h). Most fighters up to this point had one engine, but
10710-410: The mid-1930s, the majority of fighters in the US, the UK, Italy and Russia remained fabric-covered biplanes. Fighter armament eventually began to be mounted inside the wings, outside the arc of the propeller, though most designs retained two synchronized machine guns directly ahead of the pilot, where they were more accurate (that being the strongest part of the structure, reducing the vibration to which
10836-495: The most modern weapons, against an enemy in complete command of the air, fights like a savage…" Throughout the war, fighters performed their conventional role in establishing air superiority through combat with other fighters and through bomber interception, and also often performed roles such as tactical air support and reconnaissance . Fighter design varied widely among combatants. The Japanese and Italians favored lightly armed and armored but highly maneuverable designs such as
10962-508: The ocean liner Normandie in 1935. During the same period, Soviet military engineer P.K. Oshchepkov , in collaboration with the Leningrad Electrotechnical Institute , produced an experimental apparatus, RAPID, capable of detecting an aircraft within 3 km of a receiver. The Soviets produced their first mass production radars RUS-1 and RUS-2 Redut in 1939 but further development was slowed following
11088-607: The opposition. Subsequently, radar capabilities grew enormously and are now the primary method of target acquisition . Wings were made thinner and swept back to reduce transonic drag, which required new manufacturing methods to obtain sufficient strength. Skins were no longer sheet metal riveted to a structure, but milled from large slabs of alloy. The sound barrier was broken, and after a few false starts due to required changes in controls, speeds quickly reached Mach 2, past which aircraft cannot maneuver sufficiently to avoid attack. Air-to-air missiles largely replaced guns and rockets in
11214-488: The outbreak of World War I , front-line aircraft were mostly unarmed and used almost exclusively for reconnaissance . On 15 August 1914, Miodrag Tomić encountered an enemy airplane while on a reconnaissance flight over Austria-Hungary which fired at his aircraft with a revolver, so Tomić fired back. It was believed to be the first exchange of fire between aircraft. Within weeks, all Serbian and Austro-Hungarian aircraft were armed. Another type of military aircraft formed
11340-531: The outbreak of World War II in 1939. This system provided the vital advance information that helped the Royal Air Force win the Battle of Britain ; without it, significant numbers of fighter aircraft, which Great Britain did not have available, would always have needed to be in the air to respond quickly. The radar formed part of the " Dowding system " for collecting reports of enemy aircraft and coordinating
11466-487: The period of rapid re-armament in the late 1930s, were not military budgets, but civilian aircraft racing. Aircraft designed for these races introduced innovations like streamlining and more powerful engines that would find their way into the fighters of World War II. The most significant of these was the Schneider Trophy races, where competition grew so fierce, only national governments could afford to enter. At
11592-433: The period, going from a typical 180 hp (130 kW) in the 900 kg (2,000 lb) Fokker D.VII of 1918 to 900 hp (670 kW) in the 2,500 kg (5,500 lb) Curtiss P-36 of 1936. The debate between the sleek in-line engines versus the more reliable radial models continued, with naval air forces preferring the radial engines, and land-based forces often choosing inlines. Radial designs did not require
11718-456: The pilot's maneuvering with the gunner's aiming was difficult. This option was chiefly employed as a defensive measure on two-seater reconnaissance aircraft from 1915 on. Both the SPAD S.A and the Royal Aircraft Factory B.E.9 added a second crewman ahead of the engine in a pod but this was both hazardous to the second crewman and limited performance. The Sopwith L.R.T.Tr. similarly added a pod on
11844-451: The pilots reported. Attempts were made with handheld weapons such as pistols and rifles and even light machine guns, but these were ineffective and cumbersome. The next advance came with the fixed forward-firing machine gun, so that the pilot pointed the entire aircraft at the target and fired the gun, instead of relying on a second gunner. Roland Garros bolted metal deflector plates to the propeller so that it would not shoot itself out of
11970-410: The point where rotational forces prevented more fuel and air from being delivered to the cylinders, which limited horsepower. They were replaced chiefly by the stationary radial engine though major advances led to inline engines gaining ground with several exceptional engines—including the 1,145 cu in (18,760 cm ) V-12 Curtiss D-12 . Aircraft engines increased in power several-fold over
12096-706: The primary tool for short-term weather forecasting and watching for severe weather such as thunderstorms , tornadoes , winter storms , precipitation types, etc. Geologists use specialized ground-penetrating radars to map the composition of Earth's crust . Police forces use radar guns to monitor vehicle speeds on the roads. Automotive radars are used for adaptive cruise control and emergency breaking on vehicles by ignoring stationary roadside objects that could cause incorrect brake application and instead measuring moving objects to prevent collision with other vehicles. As part of Intelligent Transport Systems , fixed-position stopped vehicle detection (SVD) radars are mounted on
12222-520: The propeller arc was evident even before the outbreak of war and inventors in both France and Germany devised mechanisms that could time the firing of the individual rounds to avoid hitting the propeller blades. Franz Schneider , a Swiss engineer, had patented such a device in Germany in 1913, but his original work was not followed up. French aircraft designer Raymond Saulnier patented a practical device in April 1914, but trials were unsuccessful because of
12348-461: The propeller arc. Wing guns were tried but the unreliable weapons available required frequent clearing of jammed rounds and misfires and remained impractical until after the war. Mounting the machine gun over the top wing worked well and was used long after the ideal solution was found. The Nieuport 11 of 1916 used this system with considerable success, however, this placement made aiming and reloading difficult but would continue to be used throughout
12474-458: The propeller blades were fitted with metal wedges to protect them from ricochets . Garros' modified monoplane first flew in March 1915 and he began combat operations soon after. Garros scored three victories in three weeks before he himself was downed on 18 April and his airplane, along with its synchronization gear and propeller was captured by the Germans. Meanwhile, the synchronization gear (called
12600-426: The propensity of the machine gun employed to hang fire due to unreliable ammunition. In December 1914, French aviator Roland Garros asked Saulnier to install his synchronization gear on Garros' Morane-Saulnier Type L parasol monoplane . Unfortunately the gas-operated Hotchkiss machine gun he was provided had an erratic rate of fire and it was impossible to synchronize it with the propeller. As an interim measure,
12726-432: The radial component of the velocity is relevant. When the reflector is moving at right angle to the radar beam, it has no relative velocity. Objects moving parallel to the radar beam produce the maximum Doppler frequency shift. When the transmit frequency ( F T {\displaystyle F_{T}} ) is pulsed, using a pulse repeat frequency of F R {\displaystyle F_{R}} ,
12852-414: The response. Given all required funding and development support, the team produced working radar systems in 1935 and began deployment. By 1936, the first five Chain Home (CH) systems were operational and by 1940 stretched across the entire UK including Northern Ireland. Even by standards of the era, CH was crude; instead of broadcasting and receiving from an aimed antenna, CH broadcast a signal floodlighting
12978-465: The resulting frequency spectrum will contain harmonic frequencies above and below F T {\displaystyle F_{T}} with a distance of F R {\displaystyle F_{R}} . As a result, the Doppler measurement is only non-ambiguous if the Doppler frequency shift is less than half of F R {\displaystyle F_{R}} , called
13104-427: The roadside to detect stranded vehicles, obstructions and debris by inverting the automotive radar approach and ignoring moving objects. Smaller radar systems are used to detect human movement . Examples are breathing pattern detection for sleep monitoring and hand and finger gesture detection for computer interaction. Automatic door opening, light activation and intruder sensing are also common. A radar system has
13230-407: The scattered energy back toward the source. The extent to which an object reflects or scatters radio waves is called its radar cross-section . The power P r returning to the receiving antenna is given by the equation: where In the common case where the transmitter and the receiver are at the same location, R t = R r and the term R t ² R r ² can be replaced by R , where R
13356-416: The site. It is a radiodetermination method used to detect and track aircraft , ships , spacecraft , guided missiles , motor vehicles , map weather formations , and terrain . A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna , a receiving antenna (often the same antenna is used for transmitting and receiving) and
13482-532: The skies above the battlefield. The interceptor is a fighter designed specifically to intercept and engage approaching enemy aircraft. There are two general classes of interceptor: relatively lightweight aircraft in the point-defence role, built for fast reaction, high performance and with a short range, and heavier aircraft with more comprehensive avionics and designed to fly at night or in all weathers and to operate over longer ranges . Originating during World War I, by 1929 this class of fighters had become known as
13608-417: The sky and a number of Morane-Saulnier Ns were modified. The technique proved effective, however the deflected bullets were still highly dangerous. Soon after the commencement of the war, pilots armed themselves with pistols, carbines , grenades , and an assortment of improvised weapons. Many of these proved ineffective as the pilot had to fly his airplane while attempting to aim a handheld weapon and make
13734-408: The steady increases in aircraft weight—most modern fighters are larger and heavier than World War II medium bombers. Because of the importance of air superiority, since the early days of aerial combat armed forces have constantly competed to develop technologically superior fighters and to deploy these fighters in greater numbers, and fielding a viable fighter fleet consumes a substantial proportion of
13860-491: The target. If the wavelength is much shorter than the target's size, the wave will bounce off in a way similar to the way light is reflected by a mirror . If the wavelength is much longer than the size of the target, the target may not be visible because of poor reflection. Low-frequency radar technology is dependent on resonances for detection, but not identification, of targets. This is described by Rayleigh scattering , an effect that creates Earth's blue sky and red sunsets. When
13986-530: The technology with the U.S. during the 1940 Tizard Mission . In April 1940, Popular Science showed an example of a radar unit using the Watson-Watt patent in an article on air defence. Also, in late 1941 Popular Mechanics had an article in which a U.S. scientist speculated about the British early warning system on the English east coast and came close to what it was and how it worked. Watson-Watt
14112-528: The teen range (13–19) are generally not considered part of the series. Thus it does not include the Northrop YF-17 , which later evolved into the F/A-18. The designations F-13 and F-19 were not assigned. Fighter aircraft Fighter aircraft (early on also pursuit aircraft ) are military aircraft designed primarily for air-to-air combat . In military conflict, the role of fighter aircraft
14238-485: The top wing with no better luck. An alternative was to build a "pusher" scout such as the Airco DH.2 , with the propeller mounted behind the pilot. The main drawback was that the high drag of a pusher type's tail structure made it slower than a similar "tractor" aircraft. A better solution for a single seat scout was to mount the machine gun (rifles and pistols having been dispensed with) to fire forwards but outside
14364-879: The transmitter. The reflected radar signals captured by the receiving antenna are usually very weak. They can be strengthened by electronic amplifiers . More sophisticated methods of signal processing are also used in order to recover useful radar signals. The weak absorption of radio waves by the medium through which they pass is what enables radar sets to detect objects at relatively long ranges—ranges at which other electromagnetic wavelengths, such as visible light , infrared light , and ultraviolet light , are too strongly attenuated. Weather phenomena, such as fog, clouds, rain, falling snow, and sleet, that block visible light are usually transparent to radio waves. Certain radio frequencies that are absorbed or scattered by water vapour, raindrops, or atmospheric gases (especially oxygen) are avoided when designing radars, except when their detection
14490-464: The two Rotten could split up at any time and attack on their own. The finger-four would be widely adopted as the fundamental tactical formation during World War Two, including by the British and later the Americans. World War II featured fighter combat on a larger scale than any other conflict to date. German Field Marshal Erwin Rommel noted the effect of airpower: "Anyone who has to fight, even with
14616-487: The two length scales are comparable, there may be resonances . Early radars used very long wavelengths that were larger than the targets and thus received a vague signal, whereas many modern systems use shorter wavelengths (a few centimetres or less) that can image objects as small as a loaf of bread. Short radio waves reflect from curves and corners in a way similar to glint from a rounded piece of glass. The most reflective targets for short wavelengths have 90° angles between
14742-472: The use of radar altimeters possible in certain cases. The radar signals that are reflected back towards the radar receiver are the desirable ones that make radar detection work. If the object is moving either toward or away from the transmitter, there will be a slight change in the frequency of the radio waves due to the Doppler effect . Radar receivers are usually, but not always, in the same location as
14868-542: The very end of the inter-war period in Europe came the Spanish Civil War . This was just the opportunity the German Luftwaffe , Italian Regia Aeronautica , and the Soviet Union's Voenno-Vozdushnye Sily needed to test their latest aircraft. Each party sent numerous aircraft types to support their sides in the conflict. In the dogfights over Spain, the latest Messerschmitt Bf 109 fighters did well, as did
14994-478: The war as the weapons used were lighter and had a higher rate of fire than synchronized weapons. The British Foster mounting and several French mountings were specifically designed for this kind of application, fitted with either the Hotchkiss or Lewis Machine gun , which due to their design were unsuitable for synchronizing. The need to arm a tractor scout with a forward-firing gun whose bullets passed through
15120-443: The war. Fighter development stagnated between the wars, especially in the United States and the United Kingdom, where budgets were small. In France, Italy and Russia, where large budgets continued to allow major development, both monoplanes and all metal structures were common. By the end of the 1920s, however, those countries overspent themselves and were overtaken in the 1930s by those powers that hadn't been spending heavily, namely
15246-608: Was a 1938 Bell Lab unit on some United Air Lines aircraft. Aircraft can land in fog at airports equipped with radar-assisted ground-controlled approach systems in which the plane's position is observed on precision approach radar screens by operators who thereby give radio landing instructions to the pilot, maintaining the aircraft on a defined approach path to the runway. Military fighter aircraft are usually fitted with air-to-air targeting radars, to detect and target enemy aircraft. In addition, larger specialized military aircraft carry powerful airborne radars to observe air traffic over
15372-420: Was no longer a handicap and one or two were used, depending on requirements. This in turn required the development of ejection seats so the pilot could escape, and G-suits to counter the much greater forces being applied to the pilot during maneuvers. In the 1950s, radar was fitted to day fighters, since due to ever increasing air-to-air weapon ranges, pilots could no longer see far enough ahead to prepare for
15498-485: Was originally intended for a fighter role with the U.S. Navy , but it was canceled. This blurring follows the use of fighters from their earliest days for "attack" or "strike" operations against ground targets by means of strafing or dropping small bombs and incendiaries. Versatile multi role fighter-bombers such as the McDonnell Douglas F/A-18 Hornet are a less expensive option than having
15624-508: Was pioneered before World War I by Breguet but would find its biggest proponent in Anthony Fokker, who used chrome-molybdenum steel tubing for the fuselage structure of all his fighter designs, while the innovative German engineer Hugo Junkers developed two all-metal, single-seat fighter monoplane designs with cantilever wings: the strictly experimental Junkers J 2 private-venture aircraft, made with steel, and some forty examples of
15750-748: Was sent to the U.S. in 1941 to advise on air defense after Japan's attack on Pearl Harbor . Alfred Lee Loomis organized the secret MIT Radiation Laboratory at Massachusetts Institute of Technology , Cambridge, Massachusetts which developed microwave radar technology in the years 1941–45. Later, in 1943, Page greatly improved radar with the monopulse technique that was used for many years in most radar applications. The war precipitated research to find better resolution, more portability, and more features for radar, including small, lightweight sets to equip night fighters ( aircraft interception radar ) and maritime patrol aircraft ( air-to-surface-vessel radar ), and complementary navigation systems like Oboe used by
15876-411: Was the first to use radio waves to detect "the presence of distant metallic objects". In 1904, he demonstrated the feasibility of detecting a ship in dense fog, but not its distance from the transmitter. He obtained a patent for his detection device in April 1904 and later a patent for a related amendment for estimating the distance to the ship. He also obtained a British patent on 23 September 1904 for
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