22.图18-14表明了利用“襟翼吹气” 形式来实现短距起落的一种方法。涡轮风扇发动机具有一个齿轮传动的变距风扇和一个加大尺寸的低压压气机，空气从该压气机出口引出，再导入机翼后缘上的襟翼系统。变距风扇使低压压气机可作高转速运转并因此能在宽广的推力范围内保持高引气压力。这就在不同的飞行条件下获得极佳的控制效果。
23.在许多情况下，有必要增大垂直/短距起落飞机的升力推力，因为在正常飞行情况下，这种发动机的尺寸过大，其后果是与常规飞机相比，发动机重量和燃油消耗量都较大，升力推力的增加即升力加力可避免这种后果。升力加力可以通过许多不同的方法来实现：
（1）使用特殊发动机推力额定值。（2）在升力喷管燃气流中燃烧。（3）使用引射器系统。
升力推力的增大
(升力加力)
194
发动机的特殊推力额定值
24.经验证明额定推力的发动机结构可在短时间内提供高推力值而不降低发动机寿命。在地面效应下运转和起飞降落动作需要不到15秒的最大推力，所以在这段时间内使用短时间升力额定值是可行的。图18-5表示了15秒短时间升力额定值允许的推力与2.5分钟正常升力额定值允许值之间的比较的实例。
Vertical/short take-off and landing
增升的襟翼系统
Lift burning systems
26.
The thrust of the four nozzle lift/propulsion engine may be boosted by burning fuel in the bypass flow in the duct or plenum chamber supplying the front nozzles. This is called plenum chamber burning (P.C.B.) (fig. 18-16) and thrust of the by-pass air may be doubled by this process. This thrust capability is available for normal flight as well as take-off and landing and so can be used to increase manoeuvra-bility and give supersonic flight.
27.
The thrust of a remote lift jet can also be augmented by burning fuel in a combustion chamber just upstream of the lift nozzle (fig. 18-17). This system is commonly known as a remote augmented lift system (R.A.L.3.). The thrust boost available from the burner reduces the amount of airflow to be supplied to it and therefore reduces the size of the ducting needed to direct the air from the engine to the remote lift nozzle.
Ejectors
28. The principle of the ejector is that a small, high energy jet entrains large quantities of ambient air by viscous mixing and an increase in thrust over that of the high energy jet results. A number of projected V/STOL aircraft have incorporated this concept using either all the engine exhaust air or just the bypass flow.
引射器
28.引射器的原理是少量高能喷流通过与空气的粘性混合而夹带入大量的外界空气，其结果是使推力增加，超过只用高能量喷流所能产生的推力。一些规划中的垂直／短距起落飞机已采用这原理，它们或是使用发动机的全部排气或只用外涵气流。
高压压气机
Vertical/short take-off and landing
图18-17 远距增升系统
Fig. 18-17 Remote augmented lift system.
飞机的控制
29．垂直／短距起落飞机在起飞和过渡时的低前进
速度不允许从飞机的正常飞行控制面产生足够的空
气动力，因此有必要利用下面所列的一个或多个控
制俯仰、横滚和偏航的额外方法。
Vertical/short take-off and landing
图18-18 反作用控制系统
Fig. 18-18 Reaction control system.
AIRCRAFT CONTROL
29. The low forward speeds of V/STOL aircraft during take-off and transition do not permit the generation of adequate aerodynamic forces from the normal flight control surfaces, it is therefore necessary to provide one or more of the following additonal methods of controlling pitch, roll and yaw.
Reaction controls
30. This system bleeds air from the engine and ducts it through nozzles at the four extremities of the aircraft (fig. 18-18), The air supply to the nozzles is automatically cut off when the main engine swivelling propulsion nozzles are turned for normal flight or when the lift engines are shut down. The thrust of the control nozzles is varied by changing their area which varies the amount of airflow passed. 发动机差动节流
31．这一控制方法用于布局合理的多发动机飞机上。快速响应率对于将这些发动机用于飞机稳定性和控制是十分关键的。通常有必要将差动节流和差动推力转向起使用，以使飞机能进行各个方面的控制。
自动控制系统
32．尽管驾驶员可以手动控制垂直／短距起落飞机但采用一些自动控制是有益的，特别是可以减轻驾驶员的工作负担。驾驶员的驾驶杆以电子方式与计算机或安定面相连接，计算机从驾驶杆接收信号，将它们与从测量飞机姿态的传感器来的信号相比较，自动调节喷气反作用控制、差动节流或推力转向以保持稳定性。
反作用控制
30.该系统将空气从发动机中引出并通过飞机的四个端点上的喷管排出(图18-18)。当主发动机可转向推进喷管转入正常飞行或当升力发动机关闭时，向这些喷管输送的空气自动被切断。改变这些
控制喷管的面积就改变通过它们的气流量，从而也改变了这些控制喷管的推力。
Differential engine throttling
31. This method of control is used on multi-engined aircraft with the engines positioned in a suitable con-figuration. A rapid response rate is essential to enable the engines to be used for aircraft stability and control. It is usually necessary to combine differ-ential throttling with differential thrust vectoring to give aircraft control in all areas.
Automatic control systems
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 pilot workload. The pilot's control column is electronically connected to a computer or stabilizer that receives signals from the control column, compares them with signals from the sensors that measure the attitude of the aircraft, and automatically adjusts the reaction controls, differential throttling or thrust vectoring controls to maintain stability.
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