Abstract: High performance sail craft operate in high apparent wind velocities which induce high aerodynamic loads into the said surface. This invention provides a light weight sail construction that resists deformation of the sail surface caused by high aerodynamic loads. The sail construction consists mainly of ribs permanently affixed to the sail surface to stretch the sail material. Each rib in the sail provides the required amount of stretch in the sail material to eliminate stretch folds in the sail surface. Each rib in the sail has the stiffness or resistance to flexure varying along its length to control the sail surface curvature thereby providing a low drag airfoil for high speed sailing. A double surface sail construction is provided wherein each sail surface consists of the aforemention sail construction. A parabolic nose forms the leading edge of the double surface sail to provide smooth air flow entry. The rearward end of each sail surface is joined to form the sail trailing edge.

Abstract: Successful flight of high altitude military aircraft is dependant, in part, pon the ability of the aircraft to remain undetected during flight. However, the hot gas plume is a prime source of infrared radiation, and highly sophisticated infrared sensors have been developed in recent years. A particularly effective infrared radiation suppressor is the plug-type exhaust system. This invention increases heat exchange relationships in the plug-type infrared radiation suppressor without significantly penalizing engine power during suppressor operation.