This lecture is devoted to small gas turbines defined as those in the power range up to around 3000 shp and 4000 lb thrust, ie engines for general aviation, corporate and executive aircraft and limited trainer applications and helicopters. I do not propose to deal with APUs as these were the subject of the excellent paper given by C. H. Paul in a recent Halford Lecture.

I intend, as you may have gathered from the title, to treat this subject more in a total business context rather than as a strictly technical lecture. Recognising both the strong technical traditions of the Society and the man, Major Halford, whose memory we honour, I shall, however, take some time to deal with selected technical aspects of the subject.