Critical Mach
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Critical Mach
In aerodynamics, the critical Mach number (Mcr or M*) of an aircraft is the lowest Mach number at which the airflow over some point of the aircraft reaches the speed of sound, but does not exceed it.Clancy, L.J. ''Aerodynamics'', Section 11.6 At the lower critical Mach number, airflow around the entire aircraft is subsonic. Supersonic aircraft such as Concorde and combat aircraft also have an upper critical Mach number at which the airflow around the entire aircraft is supersonic. Aircraft flight For an aircraft in flight, the speed of the airflow around the aircraft differs considerably in places from the airspeed of the aircraft; this is due to the airflow having to speed up and slow down as it travels around the aircraft's structure. When the aircraft's airspeed reaches the critical Mach number, the speed of the airflow in some areas near the airframe reaches the speed of sound, even though the aircraft itself has an airspeed lower than Mach 1.0. This creates a weak shock wave ...
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Transonic Flow Patterns
Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transonic flow is seen at flight speeds close to the speed of sound (343 m/s at sea level), typically between Mach 0.8 and 1.2. The issue of transonic speed (or transonic region) first appeared during World War II. Pilots found as they approached the sound barrier the airflow caused aircraft to become unsteady. Experts found that shock waves can cause large-scale separation downstream, increasing drag and adding asymmetry and unsteadiness to the flow around the vehicle. Research has been done into weakening shock waves in transonic flight through the use of anti-shock bodies and supercritical airfoils. Most modern jet powered aircraft are engineered to operate at transonic air speeds. Transonic airspeeds see a rapid increase in drag from a ...
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Supermarine Spitfire
The Supermarine Spitfire is a British single-seat fighter aircraft used by the Royal Air Force and other Allied countries before, during, and after World War II. Many variants of the Spitfire were built, from the Mk 1 to the Rolls-Royce Griffon engined Mk 24 using several wing configurations and guns. It was the only British fighter produced continuously throughout the war. The Spitfire remains popular among enthusiasts; around 70 remain airworthy, and many more are static exhibits in aviation museums throughout the world. The Spitfire was designed as a short-range, high-performance interceptor aircraft by R. J. Mitchell, chief designer at Supermarine Aviation Works, which operated as a subsidiary of Vickers-Armstrong from 1928. Mitchell developed the Spitfire's distinctive elliptical wing with innovative sunken rivets (designed by Beverley Shenstone) to have the thinnest possible cross-section, achieving a potential top speed greater than that of several contemporary figh ...
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Supersonic
Supersonic speed is the speed of an object that exceeds the speed of sound ( Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times the speed of sound (Mach 5) are often referred to as hypersonic. Flights during which only some parts of the air surrounding an object, such as the ends of rotor blades, reach supersonic speeds are called transonic. This occurs typically somewhere between Mach 0.8 and Mach 1.2. Sounds are traveling vibrations in the form of pressure waves in an elastic medium. Objects move at supersonic speed when the objects move faster than the speed at which sound propagates through the medium. In gases, sound travels longitudinally at different speeds, mostly depending on the molecular mass and temperature of the gas, and pressure has little effect. Since air temperature and composition varies significantly with altitude, the speed of s ...
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Boeing
The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product support services. Boeing is among the largest global aerospace manufacturers; it is the third-largest defense contractor in the world based on 2020 revenue, and is the largest exporter in the United States by dollar value. Boeing stock is included in the Dow Jones Industrial Average. Boeing is incorporated in Delaware. Boeing was founded by William Boeing in Seattle, Washington, on July 15, 1916. The present corporation is the result of the merger of Boeing with McDonnell Douglas on August 1, 1997. Then chairman and CEO of Boeing, Philip M. Condit, assumed those roles in the combined company, while Harry Stonecipher, former CEO of McDonnell Douglas, became president and COO. The Boeing Company's corporate headquarters is in Chicago, Illi ...
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Airbus
Airbus SE (; ; ; ) is a European Multinational corporation, multinational aerospace corporation. Airbus designs, manufactures and sells civil and military aerospace manufacturer, aerospace products worldwide and manufactures aircraft throughout the world. The company has three divisions: ''Airbus Commercial Aircraft, Commercial Aircraft (Airbus S.A.S.)'', ''Airbus Defence and Space, Defence and Space'', and ''Airbus Helicopters, Helicopters'', the third being the largest in its industry in terms of revenues and turbine helicopter deliveries. As of 2019, Airbus is the world's largest airliner manufacturer. The company's main civil aeroplane business is conducted through the French company Airbus S.A.S., based in Blagnac, a suburb of Toulouse, with production and manufacturing facilities mostly in the European Union and the United Kingdom but also in China, the United States and Canada. Final assembly production is based in Toulouse, France; Hamburg, Germany; Seville, Spain; Tia ...
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Jet Airliner
A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly classified as either the large wide-body aircraft A wide-body aircraft, also known as a twin-aisle aircraft, is an airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast. The typical fuselage diameter is . In the typical wide-body economy cabi ..., medium narrow-body aircraft and smaller regional jet. Most airliners today are powered by jet engines, because they are capable of safely operating at high speeds and generate sufficient thrust to power large-capacity aircraft. The first jetliners, introduced in the 1950s, used the simpler turbojet engine; these were quickly supplanted by designs using turbofans, which are quieter and more fuel-efficient. History Early history The first air ...
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F-86 Sabre
The North American F-86 Sabre, sometimes called the Sabrejet, is a transonic jet fighter aircraft. Produced by North American Aviation, the Sabre is best known as the United States' first swept-wing fighter that could counter the swept-wing Soviet MiG-15 in high-speed dogfights in the skies of the Korean War (1950–1953), fighting some of the earliest jet-to-jet battles in history. Considered one of the best and most important fighter aircraft in that war, the F-86 is also rated highly in comparison with fighters of other eras. Although it was developed in the late 1940s and was outdated by the end of the 1950s, the Sabre proved versatile and adaptable and continued as a front-line fighter in numerous air forces. Its success led to an extended production run of more than 7,800 aircraft between 1949 and 1956, in the United States, Japan, and Italy. In addition, 738 carrier-modified versions were purchased by the US Navy as FJ-2s and -3s. Variants were built in Canada and Austr ...
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Hawker Hunter
The Hawker Hunter is a transonic British jet-powered fighter aircraft that was developed by Hawker Aircraft for the Royal Air Force (RAF) during the late 1940s and early 1950s. It was designed to take advantage of the newly developed Rolls-Royce Avon turbojet engine and the swept wing, and was the first jet-powered aircraft produced by Hawker to be procured by the RAF. On 7 September 1953, the modified first prototype broke the world air speed record for aircraft, achieving a speed of . The single-seat Hunter was introduced to service in 1954 as a manoeuvrable day interceptor aircraft, quickly succeeding first-generation jet fighters in RAF service such as the Gloster Meteor and the de Havilland Venom. The all-weather/night fighter role was filled by the Gloster Javelin. Successively improved variants of the type were produced, adopting increasingly more capable engine models and expanding its fuel capacity amongst other modifications being implemented. Hunters were also us ...
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Bell X-1
The Bell X-1 (Bell Model 44) is a rocket engine–powered aircraft, designated originally as the XS-1, and was a joint National Advisory Committee for Aeronautics– U.S. Army Air Forces–U.S. Air Force supersonic research project built by Bell Aircraft. Conceived during 1944 and designed and built in 1945, it achieved a speed of nearly in 1948. A derivative of this same design, the Bell X-1A, having greater fuel capacity and hence longer rocket burning time, exceeded in 1954. The X-1 aircraft #46-062, nicknamed ''Glamorous Glennis'' and piloted by Chuck Yeager, was the first manned airplane to exceed the speed of sound in level flight and was the first of the X-planes, a series of American experimental rocket planes (and non-rocket planes) designed for testing new technologies. Design and development Parallel development In 1942, the United Kingdom's Ministry of Aviation began a top secret project with Miles Aircraft to develop the world's first aircraft capable of brea ...
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Chuck Yeager
Brigadier General Charles Elwood Yeager ( , February 13, 1923December 7, 2020) was a United States Air Force officer, flying ace, and record-setting test pilot who in October 1947 became the first pilot in history confirmed to have exceeded the speed of sound in level flight. Yeager was raised in Hamlin, West Virginia. His career began in World War II as a private in the United States Army, assigned to the Army Air Forces in 1941. After serving as an aircraft mechanic, in September 1942, he entered enlisted pilot training and upon graduation was promoted to the rank of flight officer (the World War II Army Air Force version of the Army's warrant officer), later achieving most of his aerial victories as a P-51 Mustang fighter pilot on the Western Front, where he was credited with shooting down 11.5 enemy aircraft (the half credit is from a second pilot assisting him in a single shootdown). On October 12, 1944, he attained "ace in a day" status, shooting down five enemy aircr ...
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P-80
The Lockheed P-80 Shooting Star was the first jet fighter used operationally by the United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ... (USAAF) during World War II. Designed and built by Lockheed Corporation, Lockheed in 1943 and delivered just 143 days from the start of design, production models were flying, and two pre-production models did see very limited service in Italy just before the end of World War II. Designed with straight wings, the type saw extensive combat in Korea with the United States Air Force (USAF) as the F-80. America's first successful turbojet-powered combat aircraft, it was soon outclassed with the appearance of the swept-wing transonic MiG-15 and was quickly replaced in the air superiority role by the transonic F-86 Sabre. ...
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He 162
The Heinkel He 162 ''Volksjäger'' (German, "People's Fighter") was a German single-engine, jet-powered fighter aircraft fielded by the Luftwaffe in World War II. Developed under the Emergency Fighter Program, it was designed and built quickly and made primarily of wood as metals were in very short supply and prioritised for other aircraft. ''Volksjäger'' was the Reich Air Ministry's official name for the government design program competition won by the He 162 design. Other names given to the plane include ''Salamander'', which was the codename of its wing-construction program, and ''Spatz'' ("Sparrow"), which was the name given to the plane by the Heinkel aviation firm. The aircraft was notable for its small size; although almost the same length as a Bf 109, its wing was much shorter at vs. for the 109. Most distinctive was its top-mounted engine, which combined with the aircraft's ground-hugging landing gear allowed the engine to be easily accessed for maintenance. Thi ...
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