Patent ID: 8240597
Filing Date: 2012-08-14
Classification: B64C

Abstract:
1. A ducted fan air-vehicle comprising: an air duct comprising a duct lip and defining a circumference, wherein the duct lip comprises an internal duct lip portion and an external duct lip portion, wherein the internal duct lip portion is substantially curvature continuous around the circumference of the air duct, and the external duct lip portion is substantially curvature continuous around the circumference of the air duct, wherein the air duct comprises a plurality of cross-sections along the circumference, each of the cross-sections being taken from a plane emanating radially out from a centerline of the air duct, wherein at least some cross-sections of the plurality of cross-sections have different shapes, wherein each cross-section of the plurality of cross-sections has an a/b ratio, the “a” in the a/b ratio being defined by a first line that extends axially from a highlight location of the duct lip to a throat location of the air duct, and the “b” in the a/b ratio being defined by a second line that extends radially from the throat location of the air duct to the highlight location of the duct lip, and wherein the a/b ratio of each cross-section of the plurality of cross-sections is substantially the same.