|
Performance Envelope
In aerodynamics, the flight envelope, service envelope, or performance envelope of an aircraft or spacecraft refers to the capabilities of a design in terms of airspeed and load factor or atmospheric density, often simplified to altitude. The term is somewhat loosely applied, and can also refer to other measurements such as maneuverability. For example, when a plane is pushed, for instance by diving it at high speeds, it is said to be flown "outside the envelope", something considered rather dangerous. During vehicle test programs, flight envelope simply means that part of the aircraft or spacecraft's design capabilities that have already been successfully tested, and have therefore moved from theoretical or designed capability into a demonstrated/certified capability. Flight envelope is one of a number of related terms that are used in a similar fashion. It is perhaps the most common term because it is the oldest, first being used in the early days of test flight. It is clos ... [...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] |
Aircraft Aerodynamics
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, in a few cases, direct Powered lift, downward thrust from its engines. Common examples of aircraft include airplanes, rotorcraft (including helicopters), airships (including blimps), Glider (aircraft), gliders, Powered paragliding, paramotors, and hot air balloons. Part 1 (Definitions and Abbreviations) of Subchapter A of Chapter I of Title 14 of the U. S. Code of Federal Regulations states that aircraft "means a device that is used or intended to be used for flight in the air." The human activity that surrounds aircraft is called ''aviation''. The science of aviation, including designing and building aircraft, is called ''aeronautics.'' Aircrew, Crewed aircraft are flown by an onboard Aircraft pilot, pilot, whereas unmanned aerial vehicles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerospace Engineering
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is similar, but deals with the electronics side of aerospace engineering. "Aeronautical engineering" was the original term for the field. As flight technology advanced to include vehicles operating in outer space, the broader term "aerospace engineering" has come into use. Aerospace engineering, particularly the astronautics branch, is often colloquially referred to as "rocket science". Overview Flight vehicles are subjected to demanding conditions such as those caused by changes in atmospheric pressure and temperature, with structural loads applied upon vehicle components. Consequently, they are usually the products of various technological and engineering disciplines including aerodynamics, air propulsion, avionics, materials science, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corner Case
In engineering, a corner case (or pathological case) involves a problem or situation that occurs only outside normal operating parameters—specifically one that manifests itself when multiple environmental variables or conditions are simultaneously at extreme levels, even though each parameter is within the specified range for that parameter. For example, a loudspeaker might distort audio, but only when played at maximum volume, maximum bass, and in a high-humidity environment. Or a computer server may be unreliable, but only with the maximum complement of 64 processors, 512 GB of memory, and 10,000 signed-on users. The investigation of corner cases is of extreme importance as it can provide engineers with valuable insight into how corner case effects can be mitigated. In the case where automotive radar fails, corner case investigation can possibly tell engineers and investigators alike what may have occurred. Corner cases form part of an engineer's lexicon—especially an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manoeuvring Speed
In aviation, the maneuvering speed of an aircraft is an airspeed limitation at which the full deflection of the controls can be made at without risking structural damage.Federal Aviation AdministrationAdvisory Circular 23-19A, ''Airframe Guide for Certification of Part 23 Airplanes'', Section 48 (p.27)Retrieved 2012-01-06 The maneuvering speed of an aircraft is shown on a cockpit placard and in the aircraft's flight manual but is not commonly shown on the aircraft's airspeed indicator. In the context of air combat maneuvering (ACM), the maneuvering speed is also known as corner speed or cornering speed. Implications It has been widely misunderstood that flight below maneuvering speed will provide total protection from structural failure. In response to the destruction of American Airlines Flight 587, a CFR Final Rule was issued clarifying that "flying at or below the design maneuvering speed does not allow a pilot to make multiple large control inputs in one airplane axis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Küssner Effect
In fluid dynamics, the Küssner effect describes the unsteady aerodynamic forces on an airfoil or hydrofoil caused by encountering a transverse gust. This is directly related to the Küssner function, used in describing the effect. Both the effect and function are named after Hans Georg Küssner (1900–1984), a German aerodynamics engineer. Küssner derived an approximate model for an airfoil encountering a sudden step-like change in the transverse gust velocity; or, equivalently, as seen from a frame of reference moving with the airfoil: a sudden change in the angle of attack. The airfoil is modelled as a flat plate in a potential flow, moving with constant horizontal velocity. For this case he derived the impulse response function (known as Küssner functionBisplinghoff, Ashley and Halfman (1996) pp. 287–288.) needed to compute the unsteady lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicopter Height–velocity Diagram
The FAA states "The height–velocity diagram or H/V curve is a graph charting the safe/unsafe flight profiles relevant to a specific helicopter. As operation outside the safe area of the chart can be fatal in the event of a power or transmission failure it is sometimes referred to as the dead man's curve." The EASA refers to it as the "height/velocity avoid curve". The H/V curve is a diagram indicating the combinations of height above ground and airspeed that should be avoided due to safety concerns relating to emergency landings. It is dangerous to operate within the shaded regions of the diagram, because it may be impossible for the pilot to complete an emergency autorotation from a starting point within these regions. The H/V curve also contains a take-off profile, indicating how a pilot can start from 0 height and 0 speed, and safely traverse to cruise. At low heights with low airspeed, such as a hover taxi, the pilot can simply cushion the landing with collective by conve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coffin Corner (aviation)
Coffin corner (also known as the aerodynamic ceiling or Q corner) is the region of flight where a fast but subsonic fixed-wing aircraft's stall speed is near the critical Mach number, making it very difficult to keep an airplane in stable flight. Because the stall speed is the minimum speed required to maintain level flight, any reduction in speed will cause the airplane to stall and lose altitude. Because the critical Mach number is the maximum speed at which air can travel over the wings without losing lift due to flow separation and shock waves, any increase in speed will cause the airplane to lose lift, or to pitch heavily nose-down, and lose altitude. The "corner" refers to the triangular shape at the top of a flight envelope chart where the stall speed and critical Mach number are within a few knots of each other at a given gross weight and G-force loading. The "coffin" refers to the possible death in these kinds of stalls. The speed where they meet is the ceiling of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plus Ultra (motto)
(, , ) is a Latin phrase and the national motto of Spain. A reversal of the original phrase ''non plus ultra'' ("nothing further beyond"), said to have been inscribed as a warning on the Pillars of Hercules at the Strait of Gibraltar (which marked the edge of the known world in antiquity), it has metaphorical suggestions of taking risks and striving for excellence. Its original version, the personal motto of the Holy Roman Emperor Charles V, also Duke of Burgundy and King of Spain, was ''Plus oultre'' in French. It appears on the columns of the Spanish coat of arms, in reference to the discovery of the New World. History ''Plus oultre'', French for "further beyond", was adopted by the young Duke of Burgundy and new King of Spain Charles of Habsburg as his personal motto at the suggestion of his adviser Luigi Marliano, an Italian physician, in 1516. It was emblematic of Marliano's vision of a Christian empire spanning beyond the boundaries of the Old World, now that Charl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Aviation
General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations except for commercial air transport or aerial work, which is defined as specialized aviation services for other purposes. However, for statistical purposes, ICAO uses a definition of general aviation which includes aerial work. General aviation thus represents the " private transport" and recreational components of aviation, most of which is accomplished with light aircraft. Definition The International Civil Aviation Organization (ICAO) defines civil aviation aircraft operations in three categories: General Aviation (GA), Aerial Work (AW) and Commercial Air Transport (CAT). Aerial work operations are separated from general aviation by ICAO by this definition. Aerial work is when an aircraft is used for specialized services such as agriculture, construction, photography, surveying, observation and patrol, search and rescue, and aerial adver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Army Aviation Branch
The United States Army Aviation Branch is the Army aviation, aviation branch of the United States Army and the administrative organization that is responsible for doctrine, manning and configuration for all army aviation units. This branch was formerly considered to be one of the combat arms branches, but is today included within the "Maneuver, Fires and Effects" (MFE) classification, in accordance with current U.S. Army organizational doctrine. After the United States Army Air Corps grew into the United States Army Air Forces, Army Air Forces and split into the new service, the United States Air Force, the Army was left with its sole Fixed-wing aircraft, fixed-wing aviation units flying Taylorcraft L-2 Grasshopper observation planes for artillery units. The Army would develop a new concept of aviation using the helicopter that would show promise during the Korean War and would revolutionize warfare during the Vietnam War. History Origins of Army Aviation Army Aviation traces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
