EVOLUTION OF AVIATION AND PROPULSION SYSTEMS - THE NEXT 50 YEARS

The prospects for the longer-term evolution of aircraft and their prop ulsion systems are explored, taking a fifty year time-frame. It is con sidered that the most likely global scenario features continued econom ic development, aided by the introduction of fuel from alternative sou rces to offset a progressive shortfall in the availability of oil from relatively accessible fields. Pollution and other environmental probl ems are foreseen as exerting an increasing influence on decision makin g. Assuming such a scenario, the aviation fuel prospect is considered. It is concluded that the most likely alternative fuel for aviation in the next fifty years is some form of manufactured liquid hydrocarbon resembling current aviation kerosine, rather than liquid-hydrogen, whi ch is a candidate for later introduction. An assessment is offered of the classes of flight vehicle that will be required for civil and mili tary purposes in the time-frame under review. The implications with re gard to propulsion systems are then considered, with a discussion of d esign objectives, technological challenges and research requirements.