Patent ID: 7621482

Claim:
An internally pressurizable aircraft fuselage structure, comprising: an elongated tubular shell having a centerline axis x, opposite closed nose and tail ends, and a non-circular cross-section having a radius R(φ) at substantially every point along the x axis between the two ends, where φ is a roll elevation angle varying from 0 degrees to +360 degrees about the x axis; wherein the radius R(φ) of each cross-section of the shell varies radially by no more than ±7% from a radius r(φ) of an elliptical cross-section having a major axis with a dimension of 2·r max and a minor axis with a dimension of 2·r min , the shell has at least one structural attribute that has been tailored as a function of the elevation angle φ such that the weight of the shell required to react a design load incident thereon is less than that required to react the same design load, but wherein the at least one structural attribute has not been so tailored; the shell includes structural components including at least one external circumferential skin attached to internal longitudinal stringers and axially spaced circumferential frames, each circumferential frame having a varying depth as defined by an outer edge of the frame lying substantially along a first elliptical path and an inner edge lying substantially along a second elliptical path, and, the ratio of the major axis to the minor axis is greater for the second elliptical path than for the first elliptical path.