Nacelle and mounting arrangement for an aircraft engine

For an aircraft ducted fan engine with a core section bounded by a core case and enclosed within a core cowl, a fan section of larger diameter than said core section secured to and concentric with said core section and bounded by a fan case having a fan duct outer wall downstream thereof, said fan duct outer wall and said core cowl defining an axially extending fan duct terminating at a fan duct discharge plane for conducting a fan flow stream essentially axially, a nacelle and mounting arrangement for mounting said engine on an aircraft, with said aircraft being comprised of a main structure, said nacelle and mounting arrangement comprising:

• a pylon secured to said aircraft external to the main structure of said aircraft and adapted for said engine to be secured thereto, said pylon including a pylon beam located radially outward of said fan flow stream and secured to said aircraft and a subpylon extending from said pylon beam across said fan flow stream and terminating in an engine mount beam radially inward of said core cowl, a substantial portion of said subpylon being located within said fan duct forward of said fan duct discharge plane, said nacelle being united with said pylon to define a load path exclusive of said fan case and said core case such that when said nacelle is subjected to a nacelle aerodynamic force substantially all of said nacelle aerodynamic force is transmitted from said nacelle directly to said pylon beam rather than from said nacelle to said pylon beam by way of said fan case, said core case and said subpylon, said pylon beam also transmitting forces and torque acting on said engine to said aircraft and said subpylon being isolated from said nacelle aerodynamic force and transmitting only forces and torque acting on said engine to said pylon beam.