# US 10,766,598 B2 · Wing-to-fuselage joints and aircraft including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,766,598 B2 - Document ID: US10766598B2 - Status: Granted - Kind: B2 - Application number: 15/623,256 - Filed: 2017-06-14 - Published: 2018-12-20 - Granted: 2020-09-08 - Earliest claimed: 2017-06-14 - Assignees: The Boeing Company - Applicants: The Boeing Company - Inventors: Kenneth H. Griess; Gary E. Georgeson - Web page: https://patentgrep.com/patent/US10766598B2 ## CPC - B64C 1/26: Attaching the wing or tail units or stabilising surfaces - B64C 1/00: Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like - B64C 1/068: {Fuselage sections} - B64C 3/185: {Spars} - B64C 2001/0072: {from composite materials} - B64C: AEROPLANES; HELICOPTERS ## Abstract Wing-to-fuselage joints and aircraft including the same. An aircraft includes a fuselage with an outer fuselage skin that at least partially defines an outer surface of the fuselage and a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint. The wing assembly includes a left wing region with a lower left-wing-region skin and an upper left-wing-region skin, a right wing region with a lower right-wing-region skin and an upper right-wing-region skin, and a center wing region with a lower center-wing-region skin. The outer fuselage skin is coextensive with the lower center-wing-region skin. ## Claims ### Claim 1 An aircraft, comprising: a fuselage, wherein the fuselage comprises an outer fuselage skin that at least partially defines an outer surface of the fuselage; and a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint, wherein the wing assembly comprises: a left wing region comprising a lower left-wing-region skin that at least partially defines a lower left-wing-region airfoil surface and an upper left-wing-region skin that at least partially defines an upper left-wing-region airfoil surface; a right wing region comprising a lower right-wing-region skin that at least partially defines a lower right-wing-region airfoil surface and an upper right-wing-region skin that at least partially defines an upper right-wing-region airfoil surface; a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin; and a forward-most center wing spar and an aft-most center wing spar within the center wing region; wherein the wing-to-fuselage joint includes a single skin segment that at least partially defines both the outer fuselage skin and the lower center-wing-region skin; and wherein the single skin segment has a lateral width at a transition between the center wing region and the fuselage forward of the center wing region that is at least 25% of a maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 2 (depends on 1) The aircraft of claim 1, wherein at any longitudinal cross-section at the transition, a change in radius of curvature between the outer fuselage skin and the lower center-wing-region skin is less than 5%. ### Claim 3 (depends on 1) The aircraft of claim 1, wherein the single skin segment extends forward of the center wing region by a distance that is at least 25% of the maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 4 (depends on 1) The aircraft of claim 1 wherein the outer fuselage skin, the lower left-wing-region skin, the upper left-wing-region skin, the lower right-wing-region skin, the upper right-wing-region skin, and the lower center-wing-region skin are constructed of a fiber reinforced composite material. ### Claim 5 (depends on 1) The aircraft of claim 1, wherein the single skin segment extends forward of the center wing region by a distance that is at least 25% of the maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 6 (depends on 1) The aircraft of claim 1, wherein the single skin segment extends rearward of the center wing region by a distance that is at least 25% of the maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 7 (depends on 1) The aircraft of claim 1, wherein the single skin segment further at least partially defines at least one of the lower left-wing-region skin and the lower right-wing-region skin. ### Claim 8 (depends on 2) The aircraft of claim 2, wherein the single skin segment is a first single skin segment; wherein the wing-to-fuselage joint includes a second single skin segment that at least partially defines both the lower left-wing-region skin and the lower center-wing-region skin; and wherein the wing-to-fuselage joint further includes a third single skin segment that at least partially defines both the lower right-wing-region skin and the lower center-wing-region skin. ### Claim 9 An aircraft, comprising: a fuselage, wherein the fuselage comprises an outer fuselage skin that at least partially defines an outer surface of the fuselage; and a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint, wherein the wing assembly comprises: a left wing region comprising a lower left-wing-region skin that at least partially defines a lower left-wing-region airfoil surface and an upper left-wing-region skin that at least partially defines an upper left-wing-region airfoil surface; a right wing region comprising a lower right-wing-region skin that at least partially defines a lower right-wing-region airfoil surface and an upper right-wing-region skin that at least partially defines an upper right-wing-region airfoil surface; a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin; and a forward-most center wing spar and an aft-most center wing spar within the center wing region; wherein the wing-to-fuselage joint includes a single skin segment that at least partially defines both the outer fuselage skin and the lower center-wing-region skin; and wherein the single skin segment has a lateral width at a transition between the center wing region and the fuselage rearward of the center wing region that is at least 25% of a maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 10 (depends on 9) The aircraft of claim 9, wherein at any longitudinal cross-section at the transition, a change in radius of curvature between the outer fuselage skin and the lower center-wing-region skin is less than 5%. ### Claim 11 (depends on 9) The aircraft of claim 9, wherein the single skin segment extends forward of the center wing region by a distance that is at least 25% of the maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 12 (depends on 9) The aircraft of claim 9, wherein the single skin segment extends rearward of the center wing region by a distance that is at least 25% of the maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 13 (depends on 9) The aircraft of claim 9, wherein the single skin segment further at least partially defines at least one of the lower left-wing-region skin and lower right-wing-region skin. ### Claim 14 (depends on 9) The aircraft of claim 9, wherein the single skin segment is a first single skin segment; wherein the wing-to-fuselage joint includes a second single skin segment that at least partially defines both the lower left-wing-region skin and the lower center-wing-region skin; and wherein the wing-to-fuselage joint further includes a third single skin segment that at least partially defines both the lower right-wing-region skin and the lower center-wing-region skin. ### Claim 15 An aircraft, comprising: a fuselage, wherein the fuselage comprises an outer fuselage skin that at least partially defines an outer surface of the fuselage; and a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint, wherein the wing assembly comprises: a left wing region comprising a lower left-wing-region skin that at least partially defines a lower left-wing-region airfoil surface and an upper left-wing-region skin that at least partially defines an upper left-wing-region airfoil surface; a right wing region comprising a lower right-wing-region skin that at least partially defines a lower right-wing-region airfoil surface and an upper right-wing-region skin that at least partially defines an upper right-wing-region airfoil surface; and a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin and an upper center-wing-region skin; wherein the wing-to-fuselage joint includes a first single skin segment that at least partially defines both the outer fuselage skin and the lower center-wing-region skin; wherein the wing-to-fuselage joint includes a second single skin segment that at least partially defines both the upper left-wing-region skin and the upper center-wing-region skin; and wherein the wing-to-fuselage joint further includes a third single skin segment that at least partially defines both the upper right-wing-region skin and the upper center-wing-region skin. ### Claim 16 (depends on 15) The aircraft of claim 15, wherein the outer fuselage skin, the lower left-wing-region skin, the upper left-wing-region skin, the lower right-wing-region skin, the upper right-wing-region skin, and the lower center-wing-region skin are constructed of a fiber reinforced composite material. ### Claim 17 An aircraft, comprising: a fuselage, wherein the fuselage comprises an outer fuselage skin that at least partially defines an outer surface of the fuselage; a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint, wherein the wing assembly comprises: a left wing region comprising a lower left-wing-region skin that at least partially defines a lower left-wing-region airfoil surface and an upper left-wing-region skin that at least partially defines an upper left-wing-region airfoil surface; a right wing region comprising a lower right-wing-region skin that at least partially defines a lower right-wing-region airfoil surface and an upper right-wing-region skin that at least partially defines an upper right-wing-region airfoil surface; and a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin and an upper center-wing-region skin; and a wheel well within the fuselage rearward of the center wing region and comprising a wheel-well pressure deck constructed at least partially of an upper wheel-well skin; wherein the wing-to-fuselage joint includes a first single skin segment that at least partially defines both the outer fuselage skin and the lower center-wing-region skin; and wherein the wing-to-fuselage joint includes a second single skin segment that at least partially defines both the upper wheel-well skin and the upper center-wing-region skin. ### Claim 18 (depends on 17) The aircraft of claim 17, wherein the outer fuselage skin, the lower left-wing-region skin, the upper left-wing-region skin, the lower right-wing-region skin, the upper right-wing-region skin, and the lower center-wing-region skin are constructed of a fiber reinforced composite material. ### Claim 19 (depends on 17) The aircraft of claim 17, wherein the wheel well further comprises a rear wheel-well bulkhead extending downward from a rearward edge of the wheel-well pressure deck and constructed at least partially of a wheel-well-bulkhead skin; and wherein the wing-to-fuselage joint further includes a third single skin segment that at least partially defines both the upper center-wing-region skin and the wheel-well-bulkhead skin. ### Claim 20 An aircraft, comprising: a fuselage; and a wing assembly operably coupled to the fuselage, wherein the wing assembly comprises: a left wing region; a right wing region; a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin and an upper center-wing-region skin; and a forward-most center wing spar and an aft-most center wing spar within the center wing region; wherein a maximum vertical distance between the lower center-wing-region skin and the upper center-wing-region skin is at least 25% of a maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 21 An aircraft, comprising: a fuselage; and a wing assembly operably coupled to the fuselage, wherein the wing assembly comprises: a left wing region; a right wing region; a center wing region between the left wing region and the right wing region; and a single forward-most wing spar that spans the left wing region, the center wing region, and the right wing region. ### Claim 22 An aircraft, comprising: a fuselage; and a wing assembly operably coupled to the fuselage, wherein the wing assembly comprises: a left wing region; a right wing region; a center wing region between the left wing region and the right wing region; a single left forward-most wing spar that spans the left wing region and a left half of the center wing region; and a single right forward-most wing spar that spans the right wing region and a right half of the center wing region. ### Claim 23 An aircraft, comprising: a fuselage, wherein the fuselage comprises an outer fuselage skin that at least partially defines an outer surface of the fuselage; a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint, wherein the wing assembly comprises: a left wing region comprising a lower left-wing-region skin that at least partially defines a lower left-wing-region airfoil surface and an upper left-wing-region skin that at least partially defines an upper left-wing-region airfoil surface; a right wing region comprising a lower right-wing-region skin that at least partially defines a lower right-wing-region airfoil surface and an upper right-wing-region skin that at least partially defines an upper right-wing-region airfoil surface; and a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin; and a wheel well defined within the fuselage aft of the center wing region; wherein the wing assembly further comprises a keel beam extending from at least partially within the center wing region rearward across the wheel well; wherein the wing-to-fuselage joint includes a single skin segment that at least partially defines both the outer fuselage skin and the lower center-wing-region skin; and wherein the single skin segment at least partially defines both of the lower center-wing-region skin and the keel beam. ### Claim 24 An aircraft, comprising: a fuselage, wherein the fuselage comprises an outer fuselage skin that at least partially defines an outer surface of the fuselage; and a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint, wherein the wing assembly comprises: a left wing region comprising a lower left-wing-region skin that at least partially defines a lower left-wing-region airfoil surface and an upper left-wing-region skin that at least partially defines an upper left-wing-region airfoil surface; a right wing region comprising a lower right-wing-region skin that at least partially defines a lower right-wing-region airfoil surface and an upper right-wing-region skin that at least partially defines an upper right-wing-region airfoil surface; and a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin; wherein the lower left-wing-region skin and the lower right-wing-region skin are coextensive with the lower center-wing-region skin; and wherein at any lateral cross-section along a left transition between the lower left-wing-region skin and the lower center-wing-region skin and at any lateral cross-section along a right transition between the lower right-wing-region skin and the lower center-wing-region skin, a change in radius of curvature is less than 5%. ### Claim 25 (depends on 24) The aircraft of claim 24, wherein the wing assembly further comprises a forward-most center wing spar and an aft-most center wing spar within the center wing region; wherein the center wing region further comprises an upper center-wing-region skin; and wherein a maximum vertical distance between the lower center-wing-region skin and the upper center-wing-region skin is at least 25% of a maximum longitudinal distance between the forward-most center wing spar and the aft-most center wing spar. ### Claim 26 An aircraft, comprising: a fuselage, wherein the fuselage comprises an outer fuselage skin that at least partially defines an outer surface of the fuselage; and a wing assembly operably coupled to the fuselage via a wing-to-fuselage joint, wherein the wing assembly comprises: a left wing region comprising a lower left-wing-region skin that at least partially defines a lower left-wing-region airfoil surface and an upper left-wing-region skin that at least partially defines an upper left-wing-region airfoil surface; a right wing region comprising a lower right-wing-region skin that at least partially defines a lower right-wing-region airfoil surface and an upper right-wing-region skin that at least partially defines an upper right-wing-region airfoil surface; a center wing region between the left wing region and the right wing region and comprising a lower center-wing-region skin; and a single forward-most wing spar that spans the left wing region, the center wing region, and the right wing region.