Recent British technical progress in aeronautics part Part Two—Engine Design: A Commentary on Developments Which Have Occurred Principally During the Past Twelve Months

IN recent years there has undoubtedly been a continuously increasing rate of progress in propulsion throughout the world. In Britain this progress has been mainly confined to gas turbine engines. It is not surprising to find nothing new in the field of piston engines, but disappointing that there is so little to record about rockets and ramjets. Because of the limited development in these areas, it follows that any review of engine progress must be largely that of gas turbines in their various forms. Even here, it is difficult to ascribe specific developments to a particular year. Generally they are the result of several years' evolution through the stages of theoretical analysis, performance study, project design, test bed development and finally flight trial. Thus, at any moment, some engines may be in each of these stages. One way of dealing with this is to review progress in relation to the applications which exist or are arising. These now embrace almost the whole flight spectrum from zero to supersonic speed and it is interesting to find that it is the two extremes of the range which are receiving most attention. In all cases the aircraft design requirements introduce emphasis on some particular aspects of engine performance and so restrict it in others. A brief glance at these features is, therefore, worth while.