|
Subsonic Aircraft
A subsonic aircraft is an aircraft with a maximum speed less than the speed of sound (Mach 1). The term technically describes an aircraft that flies below its critical Mach number, typically around Mach 0.8. All current civil aircraft, including airliners, helicopters, future passenger drones, personal air vehicles and airships, as well as many military types, are subsonic. Characteristics Although high speeds are usually desirable in an aircraft, supersonic flight requires much bigger engines, higher fuel consumption and more advanced materials than subsonic flight. A subsonic type therefore costs far less than the equivalent supersonic design, has greater range and causes less harm to the environment. The less harsh subsonic environment also allows a much wider range of aircraft types, such as balloons, airships and rotorcraft, allowing them to fill a much wider range of roles. Subsonic aerodynamics Subsonic flight is characterised aerodynamically by incompressible flow, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aero L-159 ALCA (Czech Air Force) (6437228061)
The Aero L-159 ALCA is a Subsonic aircraft, subsonic light combat aircraft and Advanced Jet Trainer, advanced trainer developed in the single-seat L-159A and two-seat L-159B versions, respectively, produced in the Czech Republic by Aero Vodochody. It was derived from the Aero L-59 Super Albatros trainer, which was in turn developed from the Aero L-39 Albatros series. Development of the L-159 started in 1993 as an initiative to replace various Soviet Union, Soviet-era fighter aircraft with a modern Czech-built equivalent; it was decided against pursuing a clean-sheet design to avoid excessive costs. Development was supported by the Government of the Czech Republic, Czech government, which ordered 72 L-159A single-seat aircraft for roughly 50 billion CZK to equip the Czech Air Force. In 1998, the Boeing, Boeing Company became a strategic partner in both the project and Aero Vodochody itself. On 4 August 1997, the L-159 performed its maiden flight; on 10 April 2000, the first product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altitude
Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum (geodesy), datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric pressure). Although the term ''altitude'' is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage. In aviation, altitude is typically measured relative to mean sea level or above ground level to ensure safe navigation and flight operations. In geometry and geographical surveys, altitude helps create accurate topographic maps and understand the terrain's elevation. For high-altitude trekking and sports, knowing and adapting to altitude is vital for performance and safety. Higher altitudes mean reduced oxygen levels, which can lead to altitude sickness if proper acclimatization measures are not taken. Vertical distance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transonic
Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and Supersonic speed, 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 number, 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 Flow separation, separation downstream, increasing drag, 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 body, anti-shock bodies and supercritical airfoils. Most modern jet engine, jet powered aircraft are engineered to operate at transon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Profile Drag
Profile or profiles may refer to: Art, entertainment and media Music * Profile (Jan Akkerman album), ''Profile'' (Jan Akkerman album), 1973 * Profile (Githead album), ''Profile'' (Githead album), 2005 * Profile (Pat Donohue album), ''Profile'' (Pat Donohue album), 2005 * Profile (Duke Pearson album), ''Profile'' (Duke Pearson album), 1959 * ''Profiles (Nick Mason and Rick Fenn album), ''Profiles'' (Nick Mason and Rick Fenn album)'', a 1985 album by Nick Mason and Rick Fenn * Profiles (Gary McFarland album), ''Profiles'' (Gary McFarland album), a 1966 live album by Gary McFarland * Profile (Misako Odani album), ''Profile'' (Misako Odani album), 1997 * Profile (Wolfe Tones album), ''Profile'' (Wolfe Tones album) Film and television * Profile (2018 film), ''Profile'' (2018 film), a film directed by Timur Bekmambetov * Profile (1954 film), British thriller film * Profile (1955 TV series), ''Profile'' (1955 TV series) (1955–1957), a Canadian biographical television series * Profil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Induced Drag
Lift-induced drag, induced drag, vortex drag, or sometimes drag due to lift, in aerodynamics, is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or a lifting body redirecting air to cause lift and also in cars with airfoil wings that redirect air to cause a downforce. It is symbolized as D_\text, and the ''lift-induced drag coefficient'' as C_. For a constant amount of lift, induced drag can be reduced by increasing airspeed. A counter-intuitive effect of this is that, up to the speed-for-minimum-drag, aircraft need less power to fly faster. Induced drag is also reduced when the wingspan is higher, or for wings with wingtip devices. Explanation The total aerodynamic force acting on a body is usually thought of as having two components, lift and drag. By definition, the component of force parallel to the oncoming flow is called drag; and the component perpendicular to the oncomi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or between a fluid and a solid surface. Drag forces tend to decrease fluid velocity relative to the solid object in the fluid's path. Unlike other resistive forces, drag force depends on velocity. Drag force is proportional to the relative velocity for low-speed flow and is proportional to the velocity squared for high-speed flow. This distinction between low and high-speed flow is measured by the Reynolds number. Drag is instantaneously related to vorticity dynamics through the Josephson-Anderson relation. Examples Examples of drag include: * Net force, Net Aerodynamic force, aerodynamic or Fluid dynamics, hydrodynamic force: Drag acting opposite to the direction of movement of a solid object such as cars, aircraft, and boat hulls. * Viscou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lift/drag Ratio
In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficiency under given flight conditions. The L/D ratio for any given body will vary according to these flight conditions. For an aerofoil wing or powered aircraft, the L/D is specified when in straight and level flight. For a glider it determines the glide ratio, of distance travelled against loss of height. The term is calculated for any particular airspeed by measuring the lift generated, then dividing by the drag at that speed. These vary with speed, so the results are typically plotted on a 2-dimensional graph. In almost all cases the graph forms a U-shape, due to the two main components of drag. The L/D may be calculated using computational fluid dynamics or computer simulation. It is measured empirically by testing in a wind tunnel or in free flight t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chord (aeronautics)
In aeronautics, the chord is an imaginary straight line segment joining the leading edge and trailing edge of an aerofoil cross section parallel to the direction of the airflow. The chord length is the distance between the trailing edge and the leading edge. L. J. Clancy (1975), ''Aerodynamics'', Section 5.2, Pitman Publishing Limited, London. The point on the leading edge used to define the main chord may be the surface point of minimum radius. p.18 For a turbine aerofoil, the chord may be defined by the line between points where the front and rear of a 2-dimensional blade section would touch a flat surface when laid convex-side up. The wing, horizontal stabilizer, vertical stabilizer and propeller/rotor blades of an aircraft are all based on aerofoil sections, and the term ''chord'' or ''chord length'' is also used to describe their width. The chord of a wing, stabilizer and propeller is determined by measuring the distance between leading and trailing edges in the direc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspect Ratio (wing)
In aeronautics, the aspect ratio of a wing is the ratio of its Wingspan, span to its mean chord (aircraft), chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low aspect ratio.Kermode, A.C. (1972), ''Mechanics of Flight'', Chapter 3, (p.103, eighth edition), Pitman Publishing Limited, London Aspect ratio and other features of the Planform (aeronautics), planform are often used to predict the aerodynamic efficiency of a wing because the lift-to-drag ratio increases with aspect ratio, improving the fuel economy in aircraft, fuel economy in powered airplanes and the gliding angle of sailplanes. Definition The aspect ratio \text is the ratio of the square of the wingspan b to the projected wing area S, which is equal to the ratio of the wingspan b to the standard mean chord \text: \text \equiv \frac = \frac Mechanism As a useful simplification, an airplane in flight can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lift (force)
When a fluid flows around an object, the fluid exerts a force on the object. Lift is the Euclidean_vector#Decomposition_or_resolution, component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag (physics), 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 is defined to act perpendicular to the flow and therefore can act in any direction. If the surrounding fluid is air, the force is called an aerodynamic force. In water or any other liquid, it is called a Fluid dynamics, hydrodynamic force. Dynamic lift is distinguished from other kinds of lift in fluids. Aerostatics, 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. Planing (boat), Planing lift, in which only the lower po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wingspan
The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan of , the official record for a living bird. The term wingspan, more technically 'extent' , is also used for other winged animals such as pterosaurs, bats, insects, etc., and other aircraft such as ornithopters. In humans, the term wingspan also refers to the arm span, which is the distance between the length from the end of an individual's arm (measured at the fingertips) to the individual's fingertips on the other arm when raised parallel to the ground at shoulder height. Wingspan of aircraft The wingspan of an aircraft is always measured in a straight line, from wingtip to wingtip, regardless of wing shape or sweep. Implications for aircraft design and animal evolution The lift from wings is proportional to their area, so the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spitfire Mark19 Ps853 Planform Arp
The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and other Allied countries before, during, and after World War II. 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 a short-range, high-performance interceptor aircraft designed by R. J. Mitchell, chief designer at Supermarine Aviation Works, which operated as a subsidiary of Vickers-Armstrong from 1928. Mitchell modified the Spitfire's distinctive elliptical wing (designed by Beverley Shenstone) with innovative sunken rivets to have the thinnest possible cross-section, achieving a potential top speed greater than that of several contemporary fighter aircraft, including the Hawker Hurricane. Mitchell continued to refine the design until his death in 1937, whereupon his colleague ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
