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Mach Tuck
Mach tuck is an aerodynamic effect whereby the nose of an aircraft tends to pitch downward as the airflow around the wing reaches supersonic speeds. This diving tendency is also known as tuck under. The aircraft will first experience this effect at significantly below Mach 1. Causes Mach tuck is usually caused by two things, a rearward movement of the centre of pressure of the wing and a decrease in wing downwash velocity at the tailplane both of which cause a nose down pitching moment. For a particular aircraft design only one of these may be significant in causing a tendency to dive, delta-winged aircraft with no foreplane or tailplane in the first case and, for example, the Lockheed P-38 in the second case. Alternatively, a particular design may have no significant tendency, for example the Fokker F28 Fellowship. As an aerofoil generating lift moves through the air, the air flowing over the top surface accelerates to a higher local speed than the air flowing over the bottom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerodynamic
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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that system. The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. In mechanical engineering, force orthogonal to the main load (such as in parallel helical gears) is referred to as static thrust. Examples A fixed-wing aircraft propulsion system generates forward thrust when air is pushed in the direction opposite to flight. This can be done by different means such as the spinning blades of a propeller, the propelling jet of a jet engine, or by ejecting hot gases fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transonic Speed
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nacelle
A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached with a pylon or strut and the engine is known as a podded engine. In some cases—for instance in the typical "Farman" type "pusher" aircraft, or the World War II-era P-38 Lightning—an aircraft cockpit may also be housed in a nacelle, rather than in a conventional fuselage. Etymology Like many aviation terms, the word comes from French, in this case from a word for a small boat. Development The development of the Arado Ar 234, merging the four nacelles into two The Arado Ar 234 was one of the first operational jet aircraft with engines mounted in nacelles. During its development, the four jet engines were merged from having four distinct nacelles, all of which contained their own landing gear wheel, to two nacelles with two e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twin Boom
A twin-boom aircraft is characterised by two longitudinal booms (extended nacelle-like bodies). The booms may contain ancillary items such as fuel tanks and/or provide a supporting structure for other items. Typically, twin tailbooms support the tail surfaces, although on some types such as the Rutan Model 72 Grizzly the booms run forward of the wing. The twin-boom configuration is distinct from twin-fuselage designs in that it retains a central fuselage. Design The twin-boom configuration is distinct from the twin fuselage type in having a separate, short fuselage housing the pilot and payload. It has been adopted to resolve various design problems with the conventional empennage for aircraft in different roles. Engine mounting For a single engine with a propeller in the pusher configuration or a jet engine, a conventional tail requires the propeller or exhaust to be moved far aft, requiring either a very long driveshaft or jet pipe and thus reducing propulsive efficie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-38 Lightning
The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps by the Lockheed Corporation, the P-38 incorporated a distinctive twin-boom design with a central nacelle containing the cockpit and armament. Along with its use as a general fighter, the P-38 was used in various aerial combat roles, including as a highly effective fighter-bomber, a night fighter, and a long-range escort fighter when equipped with drop tanks. The P-38 was also used as a bomber-pathfinder, guiding streams of medium and heavy bombers, or even other P-38s equipped with bombs, to their targets."P-38 Lightning" National Museum of the United States Air Force. Retrieved 21 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Warfare Of World War II
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention ( greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). By mole fraction (i.e., by number of molecules), dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature, and atmospheric pressure vary with altitude. Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lockheed P-38H Lightning - 1 , in Sunnyvale, California
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Lockheed (originally spelled Loughead) may refer to: Brands and enterprises * Lockheed Corporation, a former American aircraft manufacturer * Lockheed Martin, formed in 1995 by the merger of Lockheed Corporation and Martin Marietta ** Lockheed Martin Aeronautics ** Lockheed Martin Space Systems * Lockheed Shipbuilding and Construction Company People * Flora Haines Loughead (1855-1943), American writer, farmer, miner * The brothers who founded the original Lockheed Corporation: ** Allan Loughead (1889–1969), American aviation pioneer ** Malcolm Loughead, American aviation pioneer Other uses * Lockheed (comics), a Marvel Comics character * Lockheed Martin Transit Center Lockheed Martin Transit Center (signed as simply Lockheed Martin station on many signs) is a light rail and transit bus station operated by Santa Clara Valley Transportation Authority (VTA), located in Sunnyvale, California. This station is s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centre Of Mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may be applied to cause a linear acceleration without an angular acceleration. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where the entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for application of Newton's laws of motion. In the case of a single rigid body, the center of mass is fixed in relation to the body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the case for hollow or open-shaped objects, such as a horseshoe. In the case of a dist ... [...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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stabilator
A stabilator is a fully movable aircraft horizontal stabilizer. It serves the usual functions of longitudinal stability, control and stick force requirements otherwise performed by the separate parts of a conventional horizontal stabilizer and elevator. Apart from reduced drag, particularly at high Mach numbers, it is a useful device for changing the aircraft balance within wide limits, and for reducing stick forces. Stabilator is a portmanteau of ''stabilizer'' and ''elevator''. It is also known as an all-moving tailplane, all-movable tail(plane), all-moving stabilizer, all-flying tail(plane), all-flying horizontal tail, full-flying stabilizer, and slab tailplane. General aviation Because it involves a moving balanced surface, a stabilator can allow the pilot to generate a given pitching moment with a lower control force. Due to the high forces involved in tail balancing loads, stabilators are designed to pivot about their aerodynamic center (near the tail's mean quarter-ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canard (aeronautics)
In aeronautics, a canard is a wing configuration in which a small forewing or foreplane is placed forward of the main wing of a fixed-wing aircraft or a weapon. The term "canard" may be used to describe the aircraft itself, the wing configuration, or the foreplane.. Canard wings are also extensively used in guided missiles and smart bombs. The term "canard" arose from the appearance of the Santos-Dumont 14-bis of 1906, which was said to be reminiscent of a duck (''canard'' in French) with its neck stretched out in flight. Despite the use of a canard surface on the first powered aeroplane, the Wright Flyer of 1903, canard designs were not built in quantity until the appearance of the Saab Viggen jet fighter in 1967. The aerodynamics of the canard configuration are complex and require careful analysis. Rather than use the conventional tailplane configuration found on most aircraft, an aircraft designer may adopt the canard configuration to reduce the main wing loading, to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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