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•        Verticaltake-off and landing 垂直起降

•        Shorttake-off and landing 短距起降

•        Characteristics特点

•        Payload有效载荷

•        Range 航程

•        Impaired受损的

•        Lift 升力

•        Envisage设想

•        Missile导弹

•        Swiveling旋转

•        Evolved进化的

•        Wing 机翼

•        Borne 承受、忍受

•        Switch-in接通

•        Downward向下

•        Counter-rotated反向旋转

•        Horizontal水平的

•        Perpendicular垂直的

•        Sprocket链轮、齿轮

•        Chain 链条

•        Simultaneously同时

•        Reinforce加强

•        Blankoff 封锁

•        Tandemfan 串列风扇

•        Hybridfan 混合风扇

•        Dispense分配

•        Permanently永久地

•        Distortion扭曲

•        Wirelacing 钢丝系带

•        Phase 阶段

•        Simplified简化

•        Multi-lobe多叶

•        Supplementary补充的

•        Flapblowing 襟翼吹气

•        Geared齿轮传动

•        Feasible可行的

•        Restoration恢复

•        Plenumchamber burning 稳压室燃烧

•        Column列

•        Stabilizer稳定器

读Sentence

•        4. Theprinciple proposed by M. Wibault was developed by using a pure jet engine witha free power turbine to drive an axial flow fan which exhausted into a pair ofswivelling nozzles, one on each side of the aircraft. A further development wasto use the fan to supercharge the engine, exhausting the by-pass air throughone pair of swivelling nozzles and adding a second pair of swivelling nozzlesto the exhaust system from the engine turbine. In this way the first ducted fanlift/propulsion engine (the Pegasus) evolved (fig. 18-2).

•        7. Thelift/propulsion engine is capable of providing thrust for both normal wingborne flight and for lift. This is achieved by changing the direction of thethrust either by a deflector system consisting of one, two or four swivellingnozzles or by a device known as a switch-in deflector which redirects theexhaust gases from a rearward facing propulsion nozzle to one or two downwardfacing lift nozzles (fig, 18-4).

•        9. Thetwo and four nozzle deflector systems use side mounted nozzles (fig. 18-6)which can rotate on simple bearings through an angle of well over 90 degrees sothat reverse thrust can be provided if required. A simple drive system, forexample, a sprocket and chain, can be used and by mechanical connections allthe nozzles can be made to deflect simultaneously. For forward flight, to avoida high performance loss and consequent increase in fuel consumption, carefuldesign of the exhaust unit and nozzle aerodynamic passages are essential tominimize the pressure losses due to turning the exhaust flow through two closecoupled bends (fig. 18-7).

•        11. Asecond type of switch-in deflector system is used on the tandem fan or hybridfan vectored thrust engine (fig. 18-9). In this case the deflector system issituated between the stages of the fan of a mixed flow turbo-fan engine. Innormal flight the valve is positioned so that the engine operates in the samemanner as a mixed flow turbo-fan and for lift thrust the valve is switched sothat the exhaust flow from the front part of the fan exhausts through downwardfacing lift nozzles and a secondary inlet is opened to provide the required airflowto the rear part of the fan and the main engine. On a purely subsonic V/STOLaircraft where fuel consumption is important the valve may be dispensed withand the engine operated permanently in the latter high by-pass mode describedabove.

•        12.Thrust deflecting nozzles will create an upstream pressure distortion which mayexcite vibration of the fan or low pressure turbine blades if the nozzle systemis close to these components. Snubbers (Part 3) may be used on the fan bladesto resist vibration. On the low pressure turbine, shrouds at the blade tips(Part 5) or wire lacing may be used to achieve the same result.

•        15.Lift engines can be designed to operate in the vertical or horizontal positionand a thrust deflecting nozzle fitted to provide some of the advantages ofthrust vectoring. Alternatively, the engine may be mounted so that it canswivel through a large angle to provide thrust vectoring. The lift-jet enginewill have an extremely hot, high velocity jet exhaust and to reduce grounderosion by the jet the normal exhaust nozzle may be replaced by a multi-lobenozzle to increase the rate of mixing with the surrounding air.

•        18.The remote lift-fan (fig. 18-12) is mounted in the aircraft wing or fuselage,and is driven mechanically or by air or gas ducted into a tip turbine, Thedrive system is provided by the main propulsion power plant or by a separateengine.

•        22.Fig. 18-14 shows one method how STOL can be achieved with a form of 'flapblowing'. The turbo-fan engine has a geared variable pitch fan and an oversizedlow pressure (L. P.) compressor from the exit of which air is bled and ductedto the flap system in the wing trailing edge. The variable pitch fan enableshigh L.P. compressor speed and thus high bleed pressure to be maintained over awide range of thrusts. This gives excellent control at greatly differentaircraft flight conditions.

•        32.Although it is possible for the pilot to control a V/STOL aircraft manually,some form of automation can be of benefit and in particular will reduce the pilotworkload. The pilot's control column is electronically connected to a computeror stabilizer that receives signals from the control column, compares them withsignals from the sensors that measure the attitude of the aircraft, andautomatically adjusts the reaction controls, differential throttling or thrustvectoring controls to maintain stability.

读全文并回答以下问题：

•       Whataircraft does V/STOL suitable to?

•       BesidesV/STOL, list the other methods of providing powered lift.

•       Describethe principle of switch-in deflector.

•       Whatare the design requirements of lift-fan engine.

•       Describethe advantage and disadvantage of remote lift system.

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