Abstract: A passive exhaust system is described that provides effective infrared signature suppression without affecting radar cross-section while maintaining stable function in crosswinds. A passive exhaust system may include an array of ducts with each duct having a primary and secondary nozzle. Central ducts draw in ambient cooling air to create a thick cooling film along exterior surfaces and cause plume dilution, stabilize the plume flow in a crosswind, and prevent heating of visible surfaces. Visible surfaces may incorporate radar absorbing materials and may be inclined at an angle or fabricated with a diffuse surface to prevent specular reflection. Visible surfaces may be constructed from or covered with low infrared emissivity materials. A variable passive flow controller ensures a sufficient velocity exhaust flow.

Abstract: A passive exhaust system is described that provides effective infrared signature suppression without affecting radar cross-section while maintaining stable function in crosswinds. A passive exhaust system may include an array of ducts with each duct having a primary and secondary nozzle. Central ducts draw in ambient cooling air to create a thick cooling film along exterior surfaces and cause plume dilution, stabilize the plume flow in a crosswind, and prevent heating of visible surfaces. Visible surfaces may incorporate radar absorbing materials and may be inclined at an angle or fabricated with a diffuse surface to prevent specular reflection Visible surfaces may be constructed from or covered with low infrared emissivity materials. A variable passive flow controller ensures a sufficient velocity exhaust flow.

Abstract: A multi-spectral shield and associated inlet structure is provided for reducing the signature of an air inlet port defined within an exterior wall of an aircraft, ship, or land-based vehicle across radar and infrared wavelengths. The multi-spectral inlet shield includes a plate disposed in front of the air inlet port. The plate is sized to visibly eclipse the air inlet port, when viewed from a direction perpendicular to the plate. The plate is supported in this position by a plate mount or splitter that extends from within the air inlet port and attaches to the plate. A support may optionally combine with the splitter to support the plate in this position. Air passes behind the plate and into the air inlet port via a channel defined around at least a portion of the plate.