This Convention poses a challenge to the lecturers. It asks us to gaze into a crystal ball and to forecast the future on the basis of the research of today. My contribution is to review the aerodynamics scene. I am the first specialist lecturer; this is perhaps a recognition that many of the significant advances of the past have been aerodynamically inspired. It is natural to start by thinking back 20 years and asking whether we would then have predicted what has come true today. In aerodynamics, there is obviously a clear answer to this question.

The purpose of this paper is to provide a view of air freight developments over the next decade.

Before we try to do that, it might be very useful to look back over the past 10 or 15 years to see where we are and to develop some understanding of how we got into the position that we find ourselves in today. Therefore, we are going to go back over the past 15 years and review the economic situation and assess the impact of selected air freighters in an attempt to develop some guidance in forecasting what we might look forward to in the next 10 years.

Over the years, the evolution of legal and contractual relationships between the suppliers of equipment and their customers has been fragmentary. Fiscal incentives for the supply of economical equipment have been rare, while incentive contracts for developing military equipment have been the cause of some controversy, particularly as regards allowances for inflation.

Immediate interests have tended to take precedence over longer term characteristics, which are often of more importance to customers. Relative merits of rewards, penalties and other motivating factors have received little attention in the literature, and philosophical considerations have been neglected.

The study of a jet impinging on a finite disc has applications in separating the stages of a multi-stage rocket during its flight. For example, the jet plume of the upper stage impinges and therefore induces a pressure field on the upper surface of the lower stage. A knowledge of this pressure field is vital in determining the trajectory of the lower stage after separation.