Nacelle

A nacelle configured to encircle an engine disposed about an axis of rotation, comprising:

• an inlet cowling defining an inlet of the nacelle, wherein the inlet cowling comprises an inlet cowling outer surface defining an outermost circumferential surface of the inlet cowling and an inlet cowling aft edge spanning radially inward from the inlet cowling outer surface, wherein the inlet cowling aft edge comprises an aft edge length and an aft edge outer point which is a radially outermost point of the inlet cowling aft edge;
• a boat tail cowling disposed aft of the inlet cowling, wherein the boat tail cowling comprises a radial flange protruding radially outward from a boat tail cowling forward portion and a boat tail cowling outer surface aft of the radial flange, wherein the boat tail cowling outer surface defines an outermost circumferential surface of the boat tail cowling, wherein the radial flange comprises a boat tail forward edge disposed adjacent to the inlet cowling aft edge,
• wherein the boat tail cowling comprises a step formed by a flange outer point of the radial flange being more radially outward from the axis of rotation than a laminar portion distance of the boat tail cowling, wherein the laminar portion distance is a radial thickness of the boat tail cowling for which a radially outermost surface is the boat tail cowling outer surface, the step being defined by a portion of the radial flange that is radially outward of the laminar portion distance;
• and
• a transition fairing coupled to the boat tail cowling outer surface of the boat tail cowling, wherein the transition fairing comprises a fairing forward edge disposed adjacent to the radial flange and a fairing ramp surface providing a transition surface between the radial flange and the boat tail cowling outer surface, wherein there is a discontinuity between the fairing ramp surface and the boat tail cowling outer surface.