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Aircraft Performance
Aircraft performance refers to the ability of an aircraft to accomplish certain useful things.Federal Aviation Administration: "Pilot's Handbook of Aeronautical Knowledge", Chapter 11/ref> It is an important consideration when designing and testing aircraft, to ensure the aircraft can be operated in an efficient and economic manner. There are typically trade-offs involved, for example an aircraft optimised for cruise performance will not necessarily be optimised for the climb. Adaptive compliant wings and variable-sweep wings are technologies aimed at improving performance during the different stages of flight. The subject of aircraft performance includes aircraft speed, ceiling, range and fuel efficiency, take-off distance required, and climb rate. It also includes aircraft controllability speeds. Aircraft manufacturers will publish performance data in an aircraft flight manual, concerning the behaviour of the aircraft under various circumstances, such as different speeds, weights ... [...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] |
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] |
Aircraft Engine Performance
Aircraft engine performance refers to factors including thrust or shaft power for fuel consumed, weight, cost, outside dimensions and life. It includes meeting regulated environmental limits which apply to emissions of noise and chemical pollutants, and regulated safety aspects which require a design that can safely tolerate environmental hazards such as birds, rain, hail and icing conditions. It is the end product that an engine company sells.Gas Turbine Performance Second Edition, Walsh and Fletcher, Blachwell Science Ltd. 2004, , Preface Aircraft engines are part of the propulsion system of an airplane, helicopter, rocket or UAV which produce rotary power transferred to a propeller or kinetic energy as a high-velocity gas exhaust stream. Aircraft engine types include turboprop, turbojet, turbofan and turboshaft. Piston engines are used in recreational personal aircraft and older aircraft. Electric engines are used in model aircraft, small drones, small UAVs and small crewed air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Engine Performance
The behavior of a jet engine and its effect both on the aircraft and the environment is categorized into different engineering areas or disciplines. The understanding of how a particular fuel flow produces a definite amount of thrust at a particular point in the flight envelope is called jet engine performance, while the emissions come under a group called combustion, and the origin of vibrations transmitted to the airframe comes under an area called rotor dynamics. Performance is the subject of a specialized discipline within aero engine design and development. In fixed-wing aircraft driven by one or more jet engines, certain aspects of performance such as thrust relate directly to the safe operation of the aircraft whereas other aspects of the engine operation such as noise and engine emissions affect the environment. The thrust, noise and emission elements of the operation of a jet engine are of vital importance in the takeoff phase of operation of the aircraft. The thrust a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Takeoff
Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff. For aircraft that take off horizontally, this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft (VTOL aircraft such as the Harrier and the Bell Boeing V22 Osprey), no runway is needed. Horizontal Power settings For light aircraft, usually full power is used during takeoff. Large transport category (airliner) aircraft may use a reduced power for takeoff, where less than full power is applied in order to prolong engine life, reduce maintenance costs and reduce noise emissions. In some emergency cases, the power used can then be increased to increase the aircraft's performance. Before takeoff, the engines, particularly piston engines, are routinely run up at high power to check for engine-related problems. The airc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landing
Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or " splashdown" as well. A normal aircraft flight would include several parts of flight including taxi, takeoff, climb, cruise, descent and landing. Aircraft Aircraft usually land at an airport on a firm runway or helicopter landing pad, generally constructed of asphalt concrete, concrete, gravel or grass. Aircraft equipped with pontoons (floatplane) or with a boat hull-shaped fuselage (a flying boat) are able to land on water. Aircraft also sometimes use skis to land on snow or ice. To land, the airspeed and the rate of descent are reduced such that the object descends at a low enough rate to allow for a gentle touch down. Landing is accomplished by slowing down and descending to the runway. This speed reduction is accomplished by re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landing Performance
The performance data for landing an aircraft can be obtained from the aircraft's flight manual or pilot's operating handbook. It will state the distance required to bring the aircraft to a stop under ideal conditions, assuming the aircraft crosses the runway threshold at a height of 50 ft, at the correct speed. The actual landing performance of an aircraft is affected by many variables which must be taken into account. Factors affecting landing performance Weight The weight of an aircraft is one of the basic factors that determines the landing distance required by an aircraft. An increase in weight increases the stall speed of the aircraft. Stall is a reduction in the lift coefficient generated by a wing as angle of attack increases. Therefore, the minimum approach speed increases as the aircraft's weight increases. The kinetic energy () that has to be overcome to stop an aircraft is a function of the mass of the aircraft and the square of its speed at touchdown. The kinetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceiling (aeronautics)
With respect to aircraft performance, a ceiling is the maximum density altitude an aircraft can reach under a set of conditions, as determined by its flight envelope. Service ceiling Service ceiling is where the rate of climb drops below a prescribed value. The service ceiling is the maximum usable altitude of an aircraft. Specifically, it is the density altitude at which flying in a clean configuration, at the best rate of climb airspeed for that altitude and with all engines operating and producing maximum continuous power, will produce a given rate of climb. A typical value might be climb, or on the order of climb for jet aircraft. The one-engine inoperative (OEI) service ceiling of a twin-engine, fixed-wing aircraft is the density altitude at which flying in a clean configuration, at the best rate of climb airspeed for that altitude with one engine producing maximum continuous power and the other engine shut down and feathered, will produce a given rate of climb, usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flight 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. 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. Flight envelope is one of a number of related terms that are all 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 flying. It is closely related to more modern terms known as extra power and a doghouse plot which are different ways of describing a flight envelope. In addition, the term has been widened in scope outside the field of engineering, to refer to the strict limits in which an event will take place or mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot And High
In aviation, hot and high is a condition of low air density due to high ambient temperature and high airport elevation. Air density decreases with increasing temperature and altitude. The lower air density reduces the power output from the aircraft's engine and also requires a higher true airspeed before the aircraft can become airborne. Aviators gauge air density by calculating the density altitude. An airport may be especially hot ''or'' high, without the other condition being present. Temperature and pressure altitude can change from one hour to the next. The fact that temperature decreases as altitude increases mitigates the "hot and high" effect to a small extent. Negative effects of reduced engine power due to hot and high conditions * Airplanes require a longer takeoff run, potentially exceeding the amount of available runway. * Reduced take-off power hampers an aircraft's ability to climb. In some cases, an aircraft may be unable to climb rapidly enough to clear terrain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag Curve
The drag curve or drag polar is the relationship between the drag on an aircraft and other variables, such as lift, the coefficient of lift, angle-of-attack or speed. It may be described by an equation or displayed as a graph (sometimes called a "polar plot"). Drag may be expressed as actual drag or the coefficient of drag. Drag curves are closely related to other curves which do not show drag, such as the power required/speed curve, or the sink rate/speed curve. The drag curve The significant aerodynamic properties of aircraft wings are summarised by two dimensionless quantities, the lift and drag coefficients and . Like other such aerodynamic quantities, they are functions only of the angle of attack , the Reynolds number and the Mach number . and can be plotted against , or can be plotted against each other. The lift and the drag forces, and , are scaled by the same factor to get and , so = . and are at right angles, with parallel to the free stream velocit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing Loading
In aerodynamics, wing loading is the total mass of an aircraft or flying animal divided by the area of its wing. The stalling speed of an aircraft in straight, level flight is partly determined by its wing loading. An aircraft or animal with a low wing loading has a larger wing area relative to its mass, as compared to one with a high wing loading. The faster an aircraft flies, the more lift can be produced by each unit of wing area, so a smaller wing can carry the same mass in level flight. Consequently, faster aircraft generally have higher wing loadings than slower aircraft. This increased wing loading also increases takeoff and landing distances. A higher wing loading also decreases maneuverability. The same constraints apply to winged biological organisms. Range of wing loadings Effect on performance Wing loading is a useful measure of the stalling speed of an aircraft. Wings generate lift owing to the motion of air around the wing. Larger wings move more air, so an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
