Helmet characterized by negative lift

Abstract

There is disclosed a helmet useful for crew members of an aircraft from which they may be ejected at high speeds. The helmet comprises a shell which fits over the head in a conventional manner and is provided with a strap which passes beneath the chin to retain the helmet on the head. A visor housing attached to, and spaced from, the shell is positioned to cover the forward crown part of the head and has portions which extend downwardly along the sides of the face of the wearer, which merge into the planes of flat areas at the ears. By this structure the usual bulbous shape at the ears commonly found in helmets is avoided and the side-to-side dimension is reduced. There are formed at the upper part of the visor housing a number of discontinuous louvers forming ridges through forward facing walls of which there are apertures. During an ejection, air scooped into the region between the visor housing and the shell exits through these louver openings. A openable closure at the rear of the visor housing closes this space between the visor housing and the shell at the rear so that the air scooped within the visor housing will not emerge from the rear. The effect of the ridges and the apertures is to disrupt the smooth air flow over the top of the helmet which would otherwise occur and which would cause undesirable lift.

Dependencies are inferred from the claim text.