Abstract: A process for producing through-holes in a sheet member to form a perforated article, such as an arcuate (non-planar) acoustic skin suitable for use in an acoustic panel of an aircraft engine nacelle. The process includes deforming a sheet member to have an arcuate shape with an arcuate surface, mounting and rotating the arcuate-shaped sheet member on a mandrel and then, while rotating the sheet member, directing an electron beam at the arcuate surface of the sheet member and deflecting the electron beam toward multiple locations on the arcuate surface to produce the through-holes through the sheet member in a defined hole pattern and thereby yield a perforated arcuate-shaped sheet member with holes having axes substantially normal to the arcuate surface. The holes are not subjected to elongation in a nonuniform manner after they are produced, and have the same transverse cross-sectional shape.

Abstract: An air cooling apparatus for an aircraft includes a cabinet that is configured to house a plurality of modules in a plurality of module accepting regions, respectively, wherein the cabinet has a backplane region. The apparatus further includes a plurality of air flow passages provided between adjacent ones of the respective module accepting regions of the cabinet. The apparatus also includes a primary air flow unit for providing primary air flow from the backplane region and through the plurality of air flow passages, to thereby cool the plurality of modules housed within the cabinet.