Nacelle inlet assembly that promotes laminar flow
An inlet assembly of a nacelle includes an inlet cowl that has a leading edge, an outer side that extends from the leading edge to an outer aft edge, and an inner side that extends from the leading edge to an inner aft edge. An exterior surface of the inlet cowl is seamless along an entire length of the outer side from the leading edge to the outer aft edge. The inlet cowl includes a lipskin that has a metallic coating. The metallic coating defines the exterior surface of the inlet cowl along the leading edge and the entire length of the outer side.
1. An inlet assembly of a nacelle, the inlet assembly comprising:
an inlet cowl including a leading edge, an outer side that extends from the leading edge to an outer aft edge, and an inner side that extends from the leading edge to an inner aft edge, the outer aft edge of the inlet cowl configured to interface with a fan cowl of the nacelle, wherein an exterior surface of the inlet cowl is seamless along an entire length of the outer side from the leading edge to the outer aft edge, the inlet cowl including a lipskin that has a metallic coating, the metallic coating defining the exterior surface of the inlet cowl along the leading edge and the outer side.
2. The inlet assembly of claim 1 , wherein the exterior surface defines a laminar flow region that extends along a contour of the outer side from the leading edge to the outer aft edge.
3. The inlet assembly of claim 1 , wherein the lipskin includes a composite panel that defines an interior surface of the inlet cowl and extends the entire length of the outer side from the leading edge to the outer aft edge.
4. The inlet assembly of claim 3 , wherein the composite panel includes a carbon fiber reinforced polymer (CFRP) material.
5. The inlet assembly of claim 3 , wherein an electrically conductive layer is sandwiched between the composite panel and the metallic coating.
6. The inlet assembly of claim 3 , wherein the lipskin defines a plurality of perforations that penetrate through the composite panel and the metallic coating along a leading edge section of the lipskin to convey a fluid through a thickness of the lipskin onto the exterior surface of the inlet cowl.
7. The inlet assembly of claim 1 , wherein the inlet cowl has an annular barrel shape oriented about a central longitudinal axis, and an extended section of the outer side, that extends to the outer aft edge, longitudinally projects beyond the inner aft edge of the inner side.
8. The inlet assembly of claim 7 , wherein the exterior surface defines a laminar flow region that extends along a contour of the outer side from the leading edge to the extended section of the outer side.
9. The inlet assembly of claim 7 , wherein the inlet cowl defines a cavity between the inner side and the outer side, and the inlet assembly further comprises support frames within the cavity, one or more of the support frames being coupled to each of the inner side and the extended section of the outer side to structurally support the extended section.
10. The inlet assembly of claim 7 , wherein the lipskin includes a composite panel that has a CFRP material and extends the entire length of the outer side from the leading edge to the outer aft edge, wherein the CFRP material structurally maintains a contour of the outer side along the extended section.
11. The inlet assembly of claim 1 , wherein the inlet cowl defines a cavity between the inner side and the outer side, and the inlet assembly further comprises one or more longitudinally-extending support frames within the cavity, the longitudinally-extending support frames defining openings to permit fluid flow therethrough.
12. The inlet assembly of claim 1 , wherein the inlet cowl defines a cavity between the inner side and the outer side, and the inlet assembly further comprises one or more circumferentially-extending support frames within the cavity, the circumferentially-extending support frames defining openings to permit fluid flow therethrough.
13. A method for producing an inlet assembly of a nacelle, the method comprising:
forming an inlet cowl that includes a leading edge, an outer side that extends from the leading edge to an outer aft edge, and an inner side that extends from the leading edge to an inner aft edge, the outer aft edge of the inlet cowl configured to interface with a fan cowl of the nacelle, wherein the inlet cowl is formed such that an exterior surface of the inlet cowl is seamless along an entire length of the outer side from the leading edge to the outer aft edge,
wherein the inlet cowl is formed by forming a lipskin that has a metallic coating, the metallic coating defining the exterior surface of the inlet cowl along the leading edge and the entire length of the outer side.
14. The method of claim 13 , wherein forming the inlet cowl comprises shaping the lipskin such that the outer side of the inlet cowl has a contour that provides a laminar flow region from the leading edge to the outer aft edge.
15. The method of claim 13 , wherein the lipskin is formed by:
applying a carbon fiber reinforced polymer (CFRP) material on a curved tool;
curing the CFRP material to form a composite panel of the lipskin; and
applying the metallic coating along an exterior surface of the composite panel to protect the composite panel from damage.
16. The method of claim 15 , further comprising:
forming a plurality of perforations along a leading edge section of the lipskin, the plurality of perforations penetrating through the composite panel and the metallic coating to convey a fluid through a thickness of the lipskin onto the exterior surface of the inlet cowl.
17. The method of claim 13 , wherein forming the inlet cowl comprises shaping the inlet cowl to have an annular barrel shape oriented about a central longitudinal axis, and the inlet cowl is formed such that an extended section of the outer side, that extends to the outer aft edge, longitudinally projects beyond the inner aft edge of the inner side.
18. The method of claim 17 , wherein the inlet cowl is formed to define a cavity between the inner side and the outer side, and the method further comprises mounting support frames within the cavity, wherein at least some of the support frames are coupled to each of the inner side and the extended section of the outer side to structurally support the extended section.
19. The method of claim 13 , wherein the inlet cowl is formed to define a cavity between the inner side and the outer side, and the method further comprises mounting support frames within the cavity, wherein at least some of the support frames extend longitudinally or circumferentially within the cavity and define openings to permit fluid flow therethrough.
20. An inlet assembly of a nacelle, the inlet assembly comprising:
an inlet cowl including a leading edge, an outer side that extends from the leading edge to an outer aft edge, and an inner side that extends from the leading edge to an inner aft edge, the outer aft edge of the inlet cowl configured to interface with a fan cowl of the nacelle, the inlet cowl having an annular barrel shape oriented about a central longitudinal axis, the inlet cowl defining a cavity aft of the leading edge between the inner side and the outer side; and
one or more support frames disposed within the cavity and extending from the inner side to the outer side of the inlet cowl to structurally support the annular barrel shape of the inlet cowl,
wherein the inlet cowl includes an extended section of the outer side that extends to the outer aft edge, the extended section longitudinally projecting beyond the inner aft edge of the inner side, and
wherein an exterior surface of the inlet cowl is seamless along an entire length of the outer side from the leading edge to the outer aft edge, and is defined by a metallic coating of a lipskin.