Patent ID: 6478253
Filing Date: 2002-11-12
Classification: B64C

Abstract:
An airframe for a passenger transport aircraft, comprising:a wing extending transverse to a longitudinal direction of the airframe; a fuselage formed as a generally tubular structure extending lengthwise along the longitudinal direction of the airframe, the fuselage defining a lower keel portion having a lower aerodynamic surface, wherein the fuselage includes a structural keel beam that extends longitudinally along the keel portion of the fuselage from the forward portion to the aft portion of the fuselage for stiffening the fuselage in longitudinal bending; wherein the wing includes a center portion that passes transversely through the fuselage above the keel portion, the fuselage having forward and aft portions respectively located forward and aft of the center portion of the wing; and wherein the lower aerodynamic surface of the keel portion in the vicinity of the wing is area-ruled such that a waterline height of said lower aerodynamic surface is greater below the wing than in the forward and aft portions of the fuselage immediately ahead of and behind the wing and the waterline height of said lower aerodynamic surface varies in the longitudinal direction so as to account for varying cross-sectional area of the wing in the longitudinal direction.