Abstract: An intake system for removing particles from air entering an engine, in which the intake air in an intake duct is divided into a primary airstream which flows upwardly at a sharp angle from the intake stream and into the engine inlet, and a secondary airstream which flows directly rearwardly with the particles to be removed, into a plenum where the particles are collected. A third airstream is formed which flows forwardly from the plenum beneath and at the sides of the intake duct, then upwardly around the sides of the intake duct and into the engine inlet.

Abstract: A nozzle for a jet stream in which the rear edge of the nozzle has a number of notches spaced therealong to widen the jet stream while directing the jet stream rearwardly of the nozzle. Each notch has a narrow front apex and a rear opening substantially wider than the apex, and each notch widens substantially smoothly and progressively from its apex to its rear opening, each notch having sides which at least over a major portion of their length diverge from each other at an angle of at least 60 degrees, and preferably at least 90 degrees. The nozzle will commonly blow into a diffuser to provide thrust augmentation but may also be used simply to blow over a flap, or it may be used without any diffusers or flaps, simply to provide noise reduction. So long as the notch divergence angle is wide enough, loss of nozzle efficiency is minimized, and when a diffuser is used, thrust augmentation is increased.