Aero Engine in the New Century -Challenge in Technology and Business-

Toasting the 100 year anniversary of controlled, powered flight, the propulsion system used on today's aircraft represents the evolution of jet propulsion based on the gas turbine, first conceived by Whittle and Von Ohain about 70 years ago. In that period, propulsion system concepts have evolved through turbo-props, turbo-jets, low by-pass ratio(BPR) turbofans to today's high BPR 2-shaft and 3-shaft turbofans. Also, this period has seen remarkable progress in the performance, reliability environmental compatibility of these propulsion systems.(omitted)