Patent ID: 9688381
Date: 2017-06-27
CPC Classifications: B64C

Claim:
1. A subfloor structure for a rotary wing aircraft having an airframe extended along an anteroposterior plane, including and delimiting the subfloor structure, the subfloor structure comprising: an integral subfloor bowl hull made of a U-shaped one-piece having material and structural continuity and jointlessly defining at least a bottom central portion, two lateral transition regions and two upward web portions, and two upper external extensions; the upward web portions integrally extending from the bottom central portion to form two longerons for the subfloor structure extending at least locally along a longitudinal axis, the bottom central portion being delimited transversally by the two upward web portions, the two upward web portions being integrated to the integral subfloor bowl hull together with the two lateral transitional regions; the lateral transition regions being opposed one to the other relatively to the anteroposterior plane, each transition region being continuously merged with the bottom central portion and one of the two upward web portions; at least a pair of crossbeams defined by inner and outer ribs and at least locally extending along a transverse direction orthogonal to the anteroposterior plane; at least a pair of outer side shells extending outward aside the bottom central portion and being attached to the integral subfloor bowl hull in the vicinity of the lateral transition regions; and floor panels defining a floor surface at least locally perpendicular to an elevation direction of the anteroposterior plane; wherein the integral subfloor bowl hull and the at least a pair of outer side shells provide an outer bottom shell for the subfloor structure; wherein the two upward web portions and the at least a pair of crossbeams provide a construction framework for the subfloor structure; wherein the two upper external extensions each laterally extend from the upward web portions as a planar surface parallel to the floor surface, each of the upward web portions having a transitional location rigidly attached to the corresponding upper external extension, each transitional location being located proximal a top end portion of the corresponding upward web portion; and wherein the planar surface of each of the two upper external extensions extends outwardly and continuously from a respective upward web portion to a respective outer side shell for direct connection therewith, the planar surface of each of the two upper external extensions extending longitudinally across at least the pair of crossbeams.