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Limit Load (aeronautics)
For aircraft specification calculation in aeronautics, limit load (LL) is the maximum load factor authorized during flight, Mathematically, limit load is LL = LLF x W, where LL = limit load, LLF = limit load factor, and W = weight of the aircraft. Limit load is constant for all weights above design gross weight. The limit load factor is reduced if gross weight is increased. But the LLF cannot be increased if the gross weight is decreased below the design gross weight. Engine mounts and other structural members are designed for the nominal LLF. The nominal or limit load Bn is the load which should only occur once (or only a very few times) during the lifetime of an aircraft. Bn may therefore only occur once during (e.g.) 60,000 hours of flying. No plastic deformation is allowed at this level of a load. The limit load can be found relatively easily by statistically analysing the data collected during the many hours of logged flights (which is continuously being gathered). See also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft
An aircraft is a vehicle 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, paramotors, and hot air balloons. The human activity that surrounds aircraft is called ''aviation''. The science of aviation, including designing and building aircraft, is called '' aeronautics.'' Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others. History Flying model craft and stories of manned flight go back many centuries; however, the first manned ascent — and safe descent — in modern times took place by larger hot-air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeronautics
Aeronautics is the science or art involved with the study, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies the aspects of "aeronautical Art, Science and Engineering" and "The profession of Aeronautics (which expression includes Astronautics)." While the term originally referred solely to ''operating'' the aircraft, it has since been expanded to include technology, business, and other aspects related to aircraft. The term "aviation" is sometimes used interchangeably with aeronautics, although "aeronautics" includes lighter-than-air craft such as airships, and includes ballistic vehicles while "aviation" technically does not. A significant part of aeronautical science is a branch of dynamics called aerodynamics, which deals with the motion of air and the way that it interacts with objects in motion, such as an aircraft. History Early ideas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Load Factor (aeronautics)
In aeronautics, the load factor is the ratio of the lift of an aircraft to its weightHurt, page 37 and represents a global measure of the stress ("load") to which the structure of the aircraft is subjected: : n = \frac, where : n is the load factor, : L is the lift : W is the weight. Since the load factor is the ratio of two forces, it is dimensionless. However, its units are traditionally referred to as g, because of the relation between load factor and apparent acceleration of gravity felt on board the aircraft. A load factor of one, or 1 g, represents conditions in straight and level flight, where the lift is equal to the weight. Load factors greater or less than one (or even negative) are the result of maneuvers or wind gusts. Load factor and g The fact that the load factor is commonly expressed in ''g'' units does not mean that it is dimensionally the same as the acceleration of gravity, also indicated with ''g''. The load factor is strictly non-dimensional. The use of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant (mathematics)
In mathematics, the word constant conveys multiple meanings. As an adjective, it refers to non-variance (i.e. unchanging with respect to some other value); as a noun, it has two different meanings: * A fixed and well-defined number or other non-changing mathematical object. The terms '' mathematical constant'' or '' physical constant'' are sometimes used to distinguish this meaning. * A function whose value remains unchanged (i.e., a constant function). Such a constant is commonly represented by a variable which does not depend on the main variable(s) in question. For example, a general quadratic function is commonly written as: :a x^2 + b x + c\, , where , and are constants (or parameters), and a variable—a placeholder for the argument of the function being studied. A more explicit way to denote this function is :x\mapsto a x^2 + b x + c \, , which makes the function-argument status of (and by extension the constancy of , and ) clear. In this example , and are co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Gross Weight
The aircraft gross weight (also known as the all-up weight and abbreviated AUW) is the total aircraft weight at ''any moment'' during the flight or ground operation. An aircraft's gross weight will decrease during a flight due to fuel and oil consumption. An aircraft's gross weight may also vary during a flight due to payload dropping or in-flight refuelling. At the moment of releasing its brakes, the gross weight of an aircraft is equal to its takeoff weight. During flight, an aircraft's gross weight is referred to as the ''en-route weight'' or ''in-flight weight''. Design weight limits (structural design weights) An aircraft's gross weight is limited by several weight restrictions in order to avoid overloading its structure or to avoid unacceptable performance or handling qualities while in operation. Aircraft gross weight limits are established during an aircraft's design and certification period and are laid down in the aircraft's type certificate and manufacturer specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Deformation
In engineering, deformation refers to the change in size or shape of an object. ''Displacements'' are the ''absolute'' change in position of a point on the object. Deflection is the relative change in external displacements on an object. Strain is the ''relative'' internal change in shape of an infinitesimally small cube of material and can be expressed as a non-dimensional change in length or angle of distortion of the cube. Strains are related to the forces acting on the cube, which are known as stress, by a stress-strain curve. The relationship between stress and strain is generally linear and reversible up until the yield point and the deformation is elastic. The linear relationship for a material is known as Young's modulus. Above the yield point, some degree of permanent distortion remains after unloading and is termed plastic deformation. The determination of the stress and strain throughout a solid object is given by the field of strength of materials and for a structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultimate Load
In engineering, the ultimate load is a statistical figure used in calculations, and should (hopefully) never actually occur. Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and ultimate loads (limit loads multiplied by prescribed factors of safety). With respect to aircraft structure and design, ultimate load is the amount of load applied to a component beyond which the component will fail. The chance that it will occur is, however, not zero, and, if it were to occur, then the relevant structure in the aircraft would stand a large chance of fracture. During the testing for determination of the loads, no fracture must occur at the ultimate load for a period of 3 seconds. This is also commonly used in knowing the properties of metal beams. For example, it is used in experiments such as T.T.M(tensile testing machine) and U.T.M(universal testing machine) The ultimate load Bu is related to the limit load Bn, using the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
