|
Variable Camber Wing
Variable camber is a feature of some of aircraft wings that changes the camber (or curvature) of the main aerofoil during flight. In one system, the leading and/or trailing edge sections of the whole wing pivot to increase the effective camber of the wing. This may be used to increase the maximum lift coefficient in order to shorten the take-off run, or to enhance manoeuvrability in the air. An early example was flown on the Westland N.16 of 1917.Lukins, A.H.; ''The book of Westland aircraft'', Aircraft (Technical) Publications Ltd, (1943 or 1944). Although flaps on the trailing or leading edge of a wing do vary the overall camber and are sometimes described as camber–changing flaps, they do not vary the main lifting surface in the same way that a variable-camber wing does. Various other mechanisms have been tried. These include a device that controls the location and shape of the entire upper surface of the airfoil, a retractable bridge that connects two separate high aspect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed-wing Aircraft
A fixed-wing aircraft is a heavier-than-air flying machine, such as an airplane, which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct from rotary-wing aircraft (in which the wings form a rotor mounted on a spinning shaft or "mast"), and ornithopters (in which the wings flap in a manner similar to that of a bird). The wings of a fixed-wing aircraft are not necessarily rigid; kites, hang gliders, variable-sweep wing aircraft and airplanes that use wing morphing are all examples of fixed-wing aircraft. Gliding fixed-wing aircraft, including free-flying gliders of various kinds and tethered kites, can use moving air to gain altitude. Powered fixed-wing aircraft (airplanes) that gain forward thrust from an engine include powered paragliders, powered hang gliders and some ground effect vehicles. Most fixed-wing aircraft are flown by a pilot on board the craft, but some ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift. Lifting structures used in water include various foils, such as hydrofoils. Hydrodynamics is the governing science, rather than aerodynamics. Applications of underwater foils occur in hydroplanes, sailboats and submarines. Etymology and usage For many centuries, the word "wing", from the Old Norse ''vængr'', referred mainly to the foremost limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camber (aerodynamics)
In aeronautics and aeronautical engineering, camber is the asymmetry between the two acting surfaces of an airfoil, with the top surface of a wing (or correspondingly the front surface of a propeller blade) commonly being more convex (positive camber). An airfoil that is not cambered is called a ''symmetric airfoil''. The benefits of cambering were discovered and first utilized by George Cayley in the early 19th century. Overview Camber is usually designed into an airfoil to maximize its lift coefficient. This minimizes the stalling speed of aircraft using the airfoil. An aircraft with cambered wings will have a lower stalling speed than an aircraft with a similar wing loading and symmetric airfoil wings. An aircraft designer may also reduce the angle of attack of the outboard section of the wings. This ensures that, as the aircraft approaches the stall, the wing root stalls before the tip, giving the aircraft resistance to spinning and maintaining aileron effectiveness c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerofoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. A solid body moving through a fluid produces an aerodynamic force. The component of this force perpendicular to the relative freestream velocity is called lift. The component parallel to the relative freestream velocity is called drag. An airfoil is a streamlined shape that is capable of generating significantly more lift than drag. Airfoils can be designed for use at different speeds by modifying their geometry: those for subsonic flight generally have a rounded leading edge, while those designed for supersonic flight tend to be slimmer with a sharp leading edge. All have a sharp trailing edge. Foils of similar function designed with water as the working fluid are called hydrofoils. The lift on an airfoil is primarily the result o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lift Coefficient
In fluid dynamics, the lift coefficient () is a dimensionless quantity that relates the lift generated by a lifting body to the fluid density around the body, the fluid velocity and an associated reference area. A lifting body is a foil or a complete foil-bearing body such as a fixed-wing aircraft. is a function of the angle of the body to the flow, its Reynolds number and its Mach number. The section lift coefficient refers to the dynamic lift characteristics of a two-dimensional foil section, with the reference area replaced by the foil chord. Abbott, Ira H., and Doenhoff, Albert E. von: ''Theory of Wing Sections''. Section 1.2 Definitions The lift coefficient ''C''L is defined by :C_\mathrm L \equiv \frac = = , where L\, is the lift force, S\, is the relevant surface area and q\, is the fluid dynamic pressure, in turn linked to the fluid density \rho\,, and to the flow speed u\,. The choice of the reference surface should be specified since it is arbitrary. For examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Westland N
Westland or Westlands may refer to: Places *Westlands, an affluent neighbourhood in the city of Nairobi, Kenya * Westlands, Staffordshire, a suburban area and ward in Newcastle-under-Lyme *Westland, a peninsula of the Shetland Mainland near Vaila, Scotland Netherlands *Westland, Netherlands (other) **Westland (municipality), Netherlands **Westland (region), Netherlands New Zealand *Westland District, a political subdivision on the West Coast of New Zealand's South Island *Westland Tai Poutini National Park, a national park **Informally, the name often used for the entire West Coast region, of which the Westland District is a part **Westland (New Zealand electorate) a former parliamentary electorate in the above area **Westland Province, a province of New Zealand from 1873–76 United States *Westland, Indiana *Westland, Putnam County, Indiana *Westland, Michigan * Westland, Oregon; see McKay Reservoir *Westland, Pennsylvania *Westland, Virginia *Westland Mall (H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flap (aircraft)
A flap is a high-lift device used to reduce the stalling speed of an aircraft wing at a given weight. Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing distance. Flaps also cause an increase in drag so they are retracted when not needed. The flaps installed on most aircraft are partial-span flaps; spanwise from near the wing root to the inboard end of the ailerons. When partial-span flaps are extended they alter the spanwise lift distribution on the wing by causing the inboard half of the wing to supply an increased proportion of the lift, and the outboard half to supply a reduced proportion of the lift. Reducing the proportion of the lift supplied by the outboard half of the wing is accompanied by a reduction in the angle of attack on the outboard half. This is beneficial because it increases the margin above the stall of the outboard half, maintaining aileron effectiveness and reduci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable-sweep Wing
A variable-sweep wing, colloquially known as a "swing wing", is an airplane wing, or set of wings, that may be swept back and then returned to its original straight position during flight. It allows the aircraft's shape to be modified in flight, and is therefore an example of a Wing configuration#Variable geometry, variable-geometry aircraft. A straight wing is most efficient for low-speed flight, but for an aircraft designed for transonic or Supersonic speed, supersonic flight it is essential that the wing be swept. Most aircraft that travel at those speeds usually have wings (either swept wing or delta wing) with a fixed sweep angle. These are simple and efficient wing designs for high speed flight, but there are performance tradeoffs. One is that the stalling speed is increased, necessitating long runways (unless complex high-lift wing devices are built in). Another is that the aircraft's fuel consumption during subsonic cruise is higher than that of an unswept wing. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable-incidence Wing
A variable-incidence wing has an adjustable angle of incidence relative to its fuselage. This allows the wing to operate at a high angle of attack for take-off and landing while allowing the fuselage to remain close to horizontal. The pivot mechanism adds extra weight over a conventional wing and increases costs, however in some applications the benefits can outweigh the costs. Several examples have flown, with one, the F-8 Crusader carrier-borne jet fighter, entering production. History Some early aeroplanes had wings which could be varied in incidence for control and trim, in place of conventional elevator control surfaces. Wing warping varied the incidence of the outer wing and was used by several pioneers, including initially the Wright brothers. Early examples of rigid variable-incidence wings were not particularly successful. They include the Mulliner Knyplane in 1911, the Ratmanoff monoplane in 1913 and the Pasul Schmidt biplane, also in 1913. A patent for a rigid var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boeing X-53 Active Aeroelastic Wing
The X-53 Active Aeroelastic Wing (AAW) development program is a completed American research project that was undertaken jointly by the Air Force Research Laboratory (AFRL), Boeing Phantom Works and NASA's Dryden Flight Research Center, where the technology was flight tested on a modified McDonnell Douglas F/A-18 Hornet. Active Aeroelastic Wing Technology is a technology that integrates wing aerodynamics, controls, and structure to harness and control wing aeroelastic twist at high speeds and dynamic pressures. By using multiple leading and trailing edge controls like "aerodynamic tabs", subtle amounts of aeroelastic twist can be controlled to provide large amounts of wing control power, while minimizing maneuver air loads at high wing strain conditions or aerodynamic drag at low wing strain conditions. This program was the first full-scale proof of AAW technology. Development Development of the initial concept was done with wind-tunnel testing in the mid 1980s under Air Force c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Compliant Wing
An adaptive compliant wing is a wing which is flexible enough for aspects of its shape to be changed in flight. Flexible wings have a number of benefits. Conventional flight control mechanisms operate using hinges, resulting in disruptions to the airflow, vortices, and in some cases, separation of the airflow. These effects contribute to the drag of the aircraft, resulting in less efficiency and higher fuel costs. Flexible aerofoils can manipulate aerodynamic forces with less disruptions to the flow, resulting in less aerodynamic drag and improved fuel economy. Shape adaptation Changing the shape of an aerodynamic surface has a direct effect on its aerodynamic properties. According to the flow condition and to the initial shape of the part, each shape variation (curvature, incidence, twist...) can have a different impact on the resulting forces and moments. This characteristic is actively pursued in adaptive wings which – by nature of their distributed compliance – can att ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
