Turbofan engine bypass and exhaust system

A turbofan engine exhaust system comprising:

• an engine nacelle including first and second curvilinear shells of constant radius of curvature for carrying air pressure loads in tension hoop stresses, and the vertical cross section of each of said shells having an arc length greater than 180.degree. of circumference, wherein, said first and second curvilinear shells are faced with leading edge bumpers and are coupled to the aircraft pylon at upper and lower bifurcations;
• a core engine cowling disposed around a core engine, a first outer surface portion of the core engine cowling having a substantially circular cross-sectional shape and a constant radius of curvature centered about a second point spaced horizontally from a first point on one side of the plane of symmetry and a second outer surface portion having a partial circular cross-sectional shape and a radius of curvature centered at a third point spaced horizontally from the first point on an opposite side of the plane of symmetry, wherein the second and third points are equidistantly spaced from the first point, and
• an inner surface of the engine nacelle including first and second portions having a partial circular cross-sectional shape and a radius of curvature whose center is in the same offset vertical planes as the core engine cowling and
• means for coupling the core engine cowling to the engine nacelle at the upper and lower bifurcations to resolve air pressure induced forces and maintain the nacelle shape in a substantially circular shape without the use of additional physical restraining means for reacting forces in the vertical direction.