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 picture info Adverse Yaw Adverse yaw is the natural and undesirable tendency for an aircraft to yaw in the opposite direction of a roll. It is caused by the difference in profile drag between the upward and downward deflected ailerons, the difference in lift and thus induced drag between left and right wings, as well as an opposite rotation of each wing's lift vector about the pitch axis due to the rolling trajectory of the aircraft. The effect can be greatly minimized with ailerons deliberately designed to create drag when deflected upward and/or mechanisms which automatically apply some amount of coordinated rudder [...More Info...]       [...Related Items...] picture info Aircraft An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships (including blimps), gliders, and hot air balloons. The human activity that surrounds aircraft is called aviation. Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers [...More Info...]       [...Related Items...] picture info Stall (flight) In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded. The critical angle of attack is typically about 15 degrees, but it may vary significantly depending on the fluid, foil, and Reynolds number. Stalls in fixed-wing flight are often experienced as a sudden reduction in lift as the pilot increases the wing's angle of attack and exceeds its critical angle of attack (which may be due to slowing down below stall speed in level flight). A stall does not mean that the engine(s) have stopped working, or that the aircraft has stopped moving — the effect is the same even in an unpowered glider aircraft [...More Info...]       [...Related Items...] picture info Wayback Machine The Wayback Machine is a digital archive of the World Wide Web, founded by the Internet Archive, a nonprofit organization based in San Francisco. Its founders, Brewster Kahle and Bruce Gilliat developed the Wayback Machine with the intention of providing "universal access to all knowledge" by preserving archived copies of defunct webpages. Since its launch in 2001, over 452 billion pages have been added to the archive [...More Info...]       [...Related Items...] picture info Special Special or the specials or variation, may refer to: .mw-parser-output .tocright{float:right;clear:right;width:auto;background:none;padding:.5em 0 .8em 1.4em;margin-bottom:.5em}.mw-parser-output .tocright-clear-left{clear:left}.mw-parser-output .tocright-clear-both{clear:both}.mw-parser-output .tocright-clear-none{clear:none} picture info International Standard Book Number The International Standard Book Number (ISBN) is a numeric commercial book identifier which is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency. An ISBN is assigned to each separate edition and variation (except reprintings) of a publication. For example, an e-book, a paperback and a hardcover edition of the same book will each have a different ISBN. The ISBN is ten digits long if assigned before 2007, and thirteen digits long if assigned on or after 1 January 2007. The method of assigning an ISBN is nation-specific and varies between countries, often depending on how large the publishing industry is within a country. The initial ISBN identification format was devised in 1967, based upon the 9-digit Standard Book Numbering (SBN) created in 1966 [...More Info...]       [...Related Items...] Spoileron In aeronautics spoilerons, also known as spoiler ailerons, are flight control surfaces, specifically spoilers that can be used asymmetrically to provide adequate roll control if aileron action would produce excessive wing twist on a very flexible wing or if wide-span flaps prevent adequate aileron roll control. Aeroelasticity Aeroelasticity is the branch of physics and engineering that studies the interactions between the inertial, elastic, and aerodynamic forces that occur when an elastic body is exposed to a fluid flow. Although historical studies have been focused on aeronautical applications, recent research has found applications in fields such as energy harvesting and understanding snoring. The study of aeroelasticity may be broadly classified into two fields: static aeroelasticity, which deals with the static or steady response of an elastic body to a fluid flow; and dynamic aeroelasticity, which deals with the body's dynamic (typically vibrational) response. Aeroelasticity draws on the study of fluid mechanics, solid mechanics, structural dynamics and dynamical systems [...More Info...]       [...Related Items...] picture info Glider (sailplane) A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding. The unpowered aircraft use naturally occurring currents of rising air in the atmosphere to remain airborne [...More Info...]       [...Related Items...] picture info De Havilland Tiger Moth The de Havilland DH.82 Tiger Moth is a 1930s biplane designed by Geoffrey de Havilland and built by the de Havilland Aircraft Company. It was operated by the Royal Air Force (RAF) and many other operators as a primary trainer aircraft. In addition to the type's principal use for ab-initio training, the Second World War saw RAF Tiger Moth operating in other capacities, including maritime surveillance, defensive anti-invasion preparations, and even some aircraft that had been outfitted to function as armed light bombers. The Tiger Moth remained in service with the RAF until it was succeeded and replaced by the de Havilland Chipmunk during the early 1950s. Many of the military surplus aircraft subsequently entered into civil operation. Many nations have used the Tiger Moth in both military and civil applications, and it remains in widespread use as a recreational aircraft in several different countries [...More Info...]       [...Related Items...] picture info Flow Separation All solid objects traveling through a fluid (or alternatively a stationary object exposed to a moving fluid) acquire a boundary layer of fluid around them where viscous forces occur in the layer of fluid close to the solid surface. Boundary layers can be either laminar or turbulent. A reasonable assessment of whether the boundary layer will be laminar or turbulent can be made by calculating the Reynolds number of the local flow conditions. Flow separation occurs when the boundary layer travels far enough against an adverse pressure gradient that the speed of the boundary layer relative to the object falls almost to zero. The fluid flow becomes detached from the surface of the object, and instead takes the forms of eddies and vortices [...More Info...]       [...Related Items...] picture info Ailerons An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around the aircraft's longitudinal axis), which normally results in a change in flight path due to the tilting of the lift vector. Movement around this axis is called 'rolling' or 'banking'. The aileron was first patented by the British scientist and inventor Matthew Piers Watt Boulton in 1868, based on his 1864 paper On Aërial Locomotion. Even though there was extensive prior art in the 19th century for the aileron and its functional analog, wing warping, in 1906 the United States granted an expansive patent to the Wright Brothers of Dayton, Ohio, for the invention of a system of aerodynamic control that manipulated an airplane's control surfaces [...More Info...]       [...Related Items...] picture info Lift Coefficient The lift coefficient (CL, CN or Cz) is a dimensionless coefficient 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. CL is a function of the angle of the body to the flow, its Reynolds number and its Mach number [...More Info...]       [...Related Items...] picture info Airfoil An airfoil (American English) or aerofoil (British English) is the shape of a wing, blade (of a propeller, rotor, or turbine), or sail (as seen in cross-section). An airfoil-shaped body moved through a fluid produces an aerodynamic force. The component of this force perpendicular to the direction of motion is called lift. The component parallel to the direction of motion is called drag. Subsonic flight airfoils have a characteristic shape with a rounded leading edge, followed by a sharp trailing edge, often with a symmetric curvature of upper and lower surfaces. Foils of similar function designed with water as the working fluid are called hydrofoils. The lift on an airfoil is primarily the result of its angle of attack and shape. When oriented at a suitable angle, the airfoil deflects the oncoming air (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection [...More Info...]       [...Related Items...] picture info Angle Of Attack In fluid dynamics, angle of attack (AOA, or ${\displaystyle \alpha }$ (Greek letter alpha)) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air. In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined [...More Info...]       [...Related Items...] picture info Lift (force) A fluid flowing past the surface of a body exerts a force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it can act in any direction at right angles to the flow. If the surrounding fluid is air, the force is called an aerodynamic force. In water or any other liquid, it is called a hydrodynamic force. Dynamic lift is distinguished from other kinds of lift in fluids. Aerostatic lift or buoyancy, in which an internal fluid is lighter than the surrounding fluid, does not require movement and is used by balloons, blimps, dirigibles, boats, and submarines [...More Info...]       [...Related Items...]