Ideal flight sheds the least amount of kinetic energy into a wake while imparting momentum sufficient to balance the vehicle weight. This combination defines a unique downwash distribution for the wake which an aircraft designer should provide for. A central fuselage, as required for the typical flight objective, presents an obstacle to this intent. A wing interrupted by a prominent fuselage is expected to shed inboard trailing vortices with central up-wash harmful to the span efficiency of the aircraft. It is proposed here that a trailing edge on the fuselage can be used to control the circulation in the central region of the aircraft so that the central downwash deficiency can be avoided. Such a Kutta Edge can further be applied as part of a high-lift system to increase central downwash by increasing the loading on the wing root and lift over the fuselage itself. Time-averaged flow fields behind a wing-body combination with and without a Kutta Edge have been measured in wind tunnel experiments. The results show that an edged aft-body does influence central circulation, as predicted. Flight with ideal wakes may be more readily attained than hitherto realized.

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This paper argues that, together with improved protection structures and energy dissipation systems, a favourable occupant position with sufficient support and restraint could reduce fatalities in aviation accidents. The crash responses of three different occupant positions were compared to justify the proposal of supporting a pilot in the rather unusual prone position. The normal seated and supine seated positions have already been adopted and implemented in aircraft. The occupant's response to specified crash pulse shapes in these two positions was compared with that of an occupant in the prone position. To obtain the best prone support configuration, different concepts were considered during the analysis. A dynamic event simulation program called ADAMS was used to perform the analysis, and existing injury criteria and a study of common causes of aviation fatalities and human body tolerance limits were used to compare the results. The study indicates that higher crash survivability in the prone position could be achieved if several guidelines are followed.