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Unstart
In supersonic aerodynamics, an unstart refers to a generally violent breakdown of the supersonic airflow. The phenomenon occurs when mass flow rate changes significantly within a duct. Avoiding unstarts is a key objective in the design of the engine air intakes (inlets U.S.) of supersonic aircraft that cruise at speeds in excess of Mach 2.2. Etymology The term originated during the use of early supersonic wind tunnels. “Starting” the supersonic wind tunnel is the process in which the air becomes supersonic; ''unstart'' of the wind tunnel is the reverse process. The shock waves that develop during the starting or unstart process may be visualized with schlieren or shadowgraph optical techniques. In some contexts, the terms aerodynamic disturbance (AD) and unstart have been synonymous. In aircraft engine intakes The design of some air intakes for supersonic aircraft can be compared to that of supersonic wind tunnels, and requires careful analysis in order to avoid unstar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inlet Shock Waves At Mach 2
An inlet is a (usually long and narrow) indentation of a shoreline, such as a small arm, bay, sound, fjord, lagoon or marsh, that leads to an enclosed larger body of water such as a lake, estuary, gulf or marginal sea. Overview In marine geography, the term "inlet" usually refers to either the actual channel between an enclosed bay and the open ocean and is often called an "entrance", or a significant recession in the shore of a sea, lake or large river. A certain kind of inlet created by past glaciation is a fjord, typically but not always in mountainous coastlines and also in montane lakes. Multi-arm complexes of large inlets or fjords may be called sounds, e.g., Puget Sound, Howe Sound, Karmsund (''sund'' is Scandinavian for "sound"). Some fjord-type inlets are called canals, e.g., Portland Canal, Lynn Canal, Hood Canal, and some are channels, e.g., Dean Channel and Douglas Channel. Tidal amplitude, wave intensity, and wave direction are all factors that in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SSM-N-9 Regulus II
The SSM-N-9 Regulus II cruise missile is a supersonic guided missile armed with a nuclear warhead, intended for launching from surface ships and submarines of the U.S. Navy (USN).Koch, Charles A"Regulus II cruise missile".''Regulus II Cruise Missile''. Retrieved: 6 January 2013. History The limitations of the Regulus I were well known by the time it entered service in 1955, so the Navy issued a specification for a surface-launched supersonic shipborne cruise missile, equipped to carry a nuclear warhead, that had greater range, accuracy and resistance to countermeasures. Development of the Regulus II was well under way when the program was canceled in favor of the UGM-27 Polaris SLBM (Submarine-Launched Ballistic Missile) system, which gave unprecedented accuracy as well as allowing the launch submarine to remain submerged and covert. Prototype and initial production missiles were later converted to KD2U-1 supersonic target drones for the US Navy and the U.S. Air Force, which use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stagnation Pressure
In fluid dynamics, stagnation pressure is the static pressure at a stagnation point in a fluid flow.Clancy, L.J., ''Aerodynamics'', Section 3.5 At a stagnation point the fluid velocity is zero. In an incompressible flow, stagnation pressure is equal to the sum of the free-stream static pressure and the free-stream dynamic pressure. Stagnation pressure is sometimes referred to as pitot pressure because the two pressures are numerically equal. Magnitude The magnitude of stagnation pressure can be derived from Bernoulli equation for incompressible flow and no height changes. For any two points 1 and 2: :P_1 + \tfrac \rho v_1^2 = P_2 + \tfrac \rho v_2^2 The two points of interest are 1) in the freestream flow at relative speed v where the pressure is called the "static" pressure, (for example well away from an airplane moving at speed v); and 2) at a "stagnation" point where the fluid is at rest with respect to the measuring apparatus (for example at the end of a pitot tube in an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subsonic Flight
Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics. The term ''aerodynamics'' is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, which was first demonstrated by Otto Lilienthal in 1891. Since then, the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations has formed a rational basis for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American F-107
The North American F-107 is North American Aviation's entry in a United States Air Force tactical fighter-bomber design competition of the 1950s. The F-107 was based on the F-100 Super Sabre, but included many innovations and radical design features, notably the over-fuselage air intakes. The competition was eventually won by the Republic F-105 Thunderchief, and most of the F-107 prototypes ended their lives as test aircraft. One is on display at the National Museum of the United States Air Force and a second at Pima Air and Space Museum. Design and development In June 1953, North American initiated an in-house study of advanced F-100 designs, leading to proposed interceptor (NAA 211: F-100BI denoting "interceptor") and fighter-bomber (NAA 212: F-100B) variants. Concentrating on the F-100B, the preliminary engineering and design work focused on a tactical fighter-bomber configuration, featuring a recessed weapons bay under the fuselage and provision for six hardpoints under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compressor Stall
A compressor stall is a local disruption of the airflow in the compressor of a gas turbine or turbocharger. A stall that results in the complete disruption of the airflow through the compressor is referred to as a compressor surge. The severity of the phenomenon ranges from a momentary power drop barely registered by the engine instruments to a complete loss of compression in case of a surge, requiring adjustments in the fuel flow to recover normal operation. Compressor stall was a common problem on early jet engines with simple aerodynamics and manual or mechanical fuel control units, but has been virtually eliminated by better design and the use of hydromechanical and electronic control systems such as Full Authority Digital Engine Control. Modern compressors are carefully designed and controlled to avoid or limit stall within an engine's operating range. Types There are two types of compressor stall: Rotating stall Rotating stall is a local disruption of airflow within the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program, aeronautics research, and outer space, space research. NASA was National Aeronautics and Space Act, established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo program, Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion (spacecraft), Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew Program, Commercial Crew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concorde
The Aérospatiale/BAC Concorde () is a retired Franco-British supersonic airliner jointly developed and manufactured by Sud Aviation (later Aérospatiale) and the British Aircraft Corporation (BAC). Studies started in 1954, and France and the UK signed a treaty establishing the development project on 29 November 1962, as the programme cost was estimated at £70 million (£ in ). Construction of the six prototypes began in February 1965, and the first flight took off from Toulouse on 2 March 1969. The market was predicted for 350 aircraft, and the manufacturers received up to 100 option orders from many major airlines. On 9 October 1975, it received its French Certificate of Airworthiness, and from the UK CAA on 5 December. Concorde is a tailless aircraft design with a narrow fuselage permitting a 4-abreast seating for 92 to 128 passengers, an ogival delta wing and a droop nose for landing visibility. It is powered by four Rolls-Royce/Snecma Olympus 593 turbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B-1 Lancer
The Rockwell B-1 Lancer is a supersonic variable-sweep wing, heavy bomber used by the United States Air Force. It is commonly called the "Bone" (from "B-One"). It is one of three strategic bombers serving in the U.S. Air Force fleet along with the B-2 Spirit and the B-52 Stratofortress . The B-1 was first envisioned in the 1960s as a platform that would combine the Mach 2 speed of the B-58 Hustler with the range and payload of the B-52, and was meant to ultimately replace both bombers. After a long series of studies, Rockwell International (now part of Boeing) won the design contest for what emerged as the B-1A. This version had a top speed of Mach 2.2 at high altitude and the ability to fly for long distances at Mach 0.85 at very low altitudes. The combination of the high cost of the aircraft, the introduction of the AGM-86 cruise missile that flew the same basic speed and distance, and early work on the B-2 stealth bomber reduced the need for the B-1. The program was canceled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vought F-8 Crusader
The Vought F-8 Crusader (originally F8U) is a single-engine, supersonic, carrier-based air superiority jet aircraft built by Vought for the United States Navy and United States Marine Corps (replacing the Vought F7U Cutlass), and for the French Navy. The first F-8 prototype was ready for flight in February 1955. The F-8 served principally in the Vietnam War. The Crusader was the last American fighter with guns as the primary weapon, earning it the title "The Last of the Gunfighters".Tillman 1990 The RF-8 Crusader was a photo-reconnaissance development and operated longer in U.S. service than any of the fighter versions. RF-8s played a crucial role in the Cuban Missile Crisis, providing essential low-level photographs impossible to acquire by other means. United States Navy Reserve units continued to operate the RF-8 until 1987. Design and development In September 1952, the United States Navy announced a requirement for a new fighter. It was to have a top speed of Mach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
