Abstract: A line of sight blocker including a cover defining a duct bounded by the cover and a heated surface when the cover is fastened over the heated surface. The cover blocks transmission of infrared radiation emitted from the heated surface; the cover comprises a material having a lower thermal conductivity than the heated surface; and the duct comprises a vent and a path for latent heat from the heated surface to escape through the vent.

Abstract: A line of sight blocker including a cover defining a duct bounded by the cover and a heated surface when the cover is fastened over the heated surface. The cover blocks transmission of infrared radiation emitted from the heated surface; the cover comprises a material having a lower thermal conductivity than the heated surface; and the duct comprises a vent and a path for latent heat from the heated surface to escape through the vent.

Abstract: An ejector including a mixing section; an inlet to the mixing section, the inlet comprising a first wall; a nozzle disposed in the inlet; the nozzle comprising the second wall defining a first channel through the nozzle, wherein the first wall and the second wall define a second channel through the inlet, the second wall has a trailing edge and a curved surface including a varying radius of curvature defining depressions extending to the trailing edge, a first flow of a first fluid into the second channel creates a pressure in the mixing section that draws a second flow of a second fluid through the first channel and into the mixing section, and the first flow and the second flow interact along the curved surface including the depressions and the trailing edge, forming a mixture comprising the first fluid and the second fluid. An outlet from the mixing section outputs the mixture, wherein the flow is well mixed and contains significant amounts of each fluid.

Abstract: A gun barrel shrouding system is capable of significantly reducing the infrared signature of a gun barrel, without directly cooling the gun barrel. A shroud is placed around the gun barrel, but the shroud does not contact the gun barrel. Air is circulated through the shroud to cool the shroud itself, but the very hot gun barrel is only partially cooled by the air as the air exits from the shroud. Since the shroud does not contact the gun barrel, the shroud may be manufactured of a lightweight and simple design, and the recoil action of the gun barrel upon firing do not need to be compensated for by the shroud.