罗尔斯-罗伊斯公司
“飞马”(Pegasus)发动机
Rolls-Royce Pegasus
罗尔斯-罗伊斯公司
RB108发动机
Rolls-Royce RB 108
The RB108 was the first engine to be designed specifically as a direct VTOL engine. First running in July 1955 the engine was sub-sequently thrust rated at 2340 lb, giving a thrust to weight ratio of 8.7:1. In addition to powering a variety of VTOL test rigs, the RB108 flew in a Gloster Meteor, the Short SC1 and the Marcel Dassault Balzac.
INTRODUCTION
1. Vertical take-off and landing (VTOL) or short take-off and landing (STOL) are desirable character-istics for any type of aircraft, provided that the normal flight performance characteristics, including payload/range, are not unreasonably impaired. Until the introduction of the gas turbine engine, with its high power/weight ratio, the only powered lift system capable of VTOL was the low disc loading rotor, as on the helicopter.
2.
Early in 1941, the late Dr A. A. Griffiths, the then Chief Scientist at Rolls-Royce, envisaged the use of the jet engine as a powered lift system. However, it was not until 1947 that a light weight jet engine, designed by Rolls-Royce for missile propulsion, existed and had a high enough thrust/weight ratio for the first pure lift-jet engine to be developed from it.
3.
In 1956 the Bristol Aero-Engine Company was approached by Monsieur Michel Wibault with a proposal to use a turbo-shaft engine and a reduction gearbox to drive four centrifugal compressors which would be situated two on each side of the aircraft. The casing of these compressors could be rotated to change direction of the thrust (fig. 18-1). The concept incorporated two original ideas i.e. the ability to deflect the thrust over the complete range of angles from the position for normal flight to that for vertical lift and a system where the resultant thrust always acted near to the centre of gravity of the aircraft.
2.1941年初，罗尔斯-罗伊斯公司当时的首席科学家格里菲斯博士(Dr.A.A.Griffiths)就设想过利用喷气发动机作为动力升力系统。但是直到1947年罗尔斯-罗伊斯公司设计的用作导弹推进装置的轻重量喷气发动机才终于问世，并具有足够高的推重比，使首台纯升力喷气发动机能从它发展出来。
Vertical/short take-off and landing
3.1956年布里斯托航空发动机公司收到米歇尔 维博特(Michel Wibault)先生的一个建议，用涡轮轴发动机和减速器来驱动装在飞机两侧的4个离心式压气机(每侧2个)。这些压气机的机匣可以旋转以改变推力的方向(图18-1)。这一概念包括两个原先的设想，即具有从正常飞行位置到垂直升力的整个角度范围内将推力变向的能力，和一个使总推力总是作用在飞机重心附近的系统。
4. The principle proposed by M. Wibault was each side of the aircraft. A further development was developed by using a pure jet engine with a free to use the fan to supercharge the engine, exhausting power turbine to drive an axial flow fan which the by-pass air through one pair of swivelling nozzles exhausted into a pair of swivelling nozzles, one on and adding a second pair of swivelling nozzles to the
图18-1 1956年米歇尓 维博特的对地攻击旋翼飞机(方案)
离心式鼓风机
涡轴发动机
齿轮箱
4.M.维博特提出的原理得到了发展，即利用一台带自由功力涡轮的纯喷气发动机来驱动轴流式风扇，而该风扇向位于飞机两侧的一对可转向喷管喷气。由此更进一步的发展是利用风扇为发动机加压，通过一对可转向喷管排放外涵空气并为发动机涡轮排气系统增加第二对可转向喷管。正是用这种方法研制出了第一台涵道风扇升力／推力发动机(图18-2中的“飞马”发动机)。
图18-2 升力/推力发动机
Fig. 18-2 Lift/Propulsion engine.
5．“飞马”发动机用于“鹞”(Harrier)式垂自／短距起
落战斗机(图18-2)的经验，导致了对短距起飞垂直降落实用技术的开发。利用这种技术，即使在短距起飞滑跑后，飞机机翼产生的额外升力与纯垂直起飞的飞机相比较可大大提高飞机的商载／航程能力。垂直降落与短距降落相比具有若干使用方面的优点，所以这种降落方式得以继续使用。
Vertical/short take-off and landing
提供动力升力的方法
6．尽管 “飞马”发动机是西方世界中唯一服役的垂直／短距起落发动机，但还有若干提供动力升力的方法，例如：
(1)将排气也即发动机推力偏转(改变矢量方向)。
(2)使用专门设计的只提供升力的发动机。
(3)由发动机或一个独立的动力装置驱动远离发动机的升力系统。
(4)旋转发动机。
(5)对短距起落飞机而言，利用发动机引气来增加机翼四周的环流，从而增加升力。
在几种垂直／短距起落飞机方案上。都曾把上述方法中的两种或更多种组合起来使用。
exhaust system from the engine turbine. In this way the first ducted fan lift/propulsion engine (the Pegasus) evolved (fig. 18-2).
5. Subsequent experience with the Pegasus engine in the Harrier V/STOL fighter aircraft (fig. 18-3), lead to the development of the short take-off and vertical landing (STOVL) operational technique. In this way the additional lift generated by the aircraft wing, even after a short take-off run, provided a large increase in the payload/range capability of the aircraft compared to a pure vertical take-off. Vertical landing had several operational advantages compared to a short landing and so was maintained.
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