Nacelle inlet having an angle or curved aft bulkhead

Abstract

A construction of a nacelle inlet aft bulkhead has a curved or angled cross-section configuration between a connection of an outer edge of the aft bulkhead to an outer barrel of the nacelle inlet and a connection of an inner edge of the aft bulkhead to an inner barrel of the nacelle inlet. The curved or angled cross-section configuration of the aft bulkhead gives the bulkhead flexibility to avoid serious damage to the bulkhead in high load cases such as an fan blade off event. The curved or angled cross-section configuration also removes the need for a spring ring attached between the aft bulkhead and the inner barrel of the nacelle inlet. The curved or angled cross-section configuration also provides design flexibility to terminate the outer barrel of the nacelle inlet at an optimized location rearwardly to increase laminar air flow over the nacelle and reduce drag.

1 . A nacelle inlet of an aircraft engine comprising:
 a lipskin on a forward end of the nacelle inlet;   an outer barrel on an exterior of the nacelle inlet, the outer barrel extending rearwardly from the lipskin;   an inner barrel on an interior of the nacelle inlet, the inner barrel extending rearwardly from the lipskin; and,   an aft bulkhead on the nacelle inlet, the aft bulkhead having an outer edge connected to the outer barrel and the aft bulkhead having an inner edge connected to the inner barrel, the outer edge of the aft bulkhead being positioned rearwardly of the inner edge of the aft bulkhead.   
     
     
         2 . The nacelle inlet of  claim 1 , further comprising:
 an engine fan case attachment ring;   the inner edge of the aft bulkhead being connected to the engine fan case attachment ring;   the inner barrel being connected to the engine fan case attachment ring;   the outer barrel having a rear edge, the outer edge of the aft bulkhead being connected to the rear edge of the outer barrel, and a configuration of the aft bulkhead positioning the rear edge of the outer barrel rearwardly of the engine fan case attachment ring.   
     
     
         3 . The nacelle inlet of  claim 2 , further comprising:
 the rearward surface of the aft bulkhead being a smooth, continuous surface that extends between the outer edge of the aft bulkhead and the inner edge of the aft bulkhead.   
     
     
         4 . The nacelle inlet of  claim 2 , further comprising:
 the aft bulkhead rearward surface having a concave configuration between the outer edge of the aft bulkhead and the inner edge of the aft bulkhead.   
     
     
         5 . The nacelle inlet of  claim 2 , further comprising:
 the rearward surface of the aft bulkhead having a flat configuration between the outer edge of the aft bulkhead and the inner edge of the aft bulkhead.   
     
     
         6 . The nacelle inlet of  claim 2 , further comprising:
 the outer edge of the aft bulkhead being positioned rearwardly of the engine fan case attachment ring.   
     
     
         7 . The nacelle inlet of  claim 2 , further comprising:
 the outer edge of the aft bulkhead being connected directly to the rear edge of the outer barrel.   
     
     
         8 . A nacelle inlet of an aircraft engine comprising:
 a lipskin on a forward end of the nacelle inlet;   an outer barrel on an exterior of the nacelle inlet, the outer barrel extending rearwardly from the lipskin to a rear edge of the outer barrel;   an inner barrel on an interior of the nacelle inlet, extending rearwardly from the lipskin to a rear edge of the inner barrel; and,   the rear edge of the outer barrel being positioned rearwardly of the rear edge of the inner barrel.   
     
     
         9 . The nacelle inlet of  claim 8 , further comprising:
 an aft bulkhead connected between the rear edge of the outer barrel and the rear edge of the inner barrel.   
     
     
         10 . The nacelle inlet of  claim 9 , further comprising:
 the aft bulkhead having an outer edge connected to the rear edge of the outer barrel;   the aft bulkhead having an inner edge connected to the rear edge of the inner barrel; and,   the outer edge of the aft bulkhead being positioned rearwardly of the inner edge of the aft bulkhead.   
     
     
         11 . The nacelle inlet of  claim 9 , further comprising:
 an engine fan case attachment ring;   the inner edge of the aft bulkhead being connected to the engine fan case attachment ring;   the inner barrel being connected to the engine fan case attachment ring;   the outer barrel having a rear edge, the outer edge of the aft bulkhead being connected to the rear edge of the outer barrel, and a configuration of the aft bulkhead positioning the rear edge of the outer barrel rearwardly of the engine fan case attachment ring.   
     
     
         12 . The nacelle inlet of  claim 9 , further comprising:
 the aft bulkhead having a rearward surface; and,   the aft bulkhead rearward surface being a smooth, continuous surface that extends between the rear edge of the outer barrel and the rear edge of the inner barrel.   
     
     
         13 . The nacelle inlet of  claim 9 , further comprising:
 the aft bulkhead having a rearward surface; and,   the rearward surface of the aft bulkhead having a concave configuration between the rear edge of the outer barrel and the rear edge of the inner barrel.   
     
     
         14 . The nacelle inlet of  claim 9 , further comprising:
 the aft bulkhead having a rearward surface; and,   the rearward surface of the aft bulkhead having a flat configuration between the rear edge of the outer barrel and the rear edge of the inner barrel.   
     
     
         15 . The nacelle inlet of  claim 8 , further comprising:
 an engine fan case attachment ring on the nacelle inlet; and,   the rear edge of the outer barrel being positioned rearwardly of the engine fan case attachment ring.   
     
     
         16 . The nacelle inlet of  claim 9 , further comprising:
 an engine fan case attachment ring on the nacelle inlet; and,   the aft bulkhead having an inner edge connected to the engine fan case attachment ring.   
     
     
         17 . The nacelle inlet of  claim 16 , further comprising:
 the engine fan case attachment ring being connected to the rear edge of the inner barrel.   
     
     
         18 . A method of absorbing force from a fan blade off event exerted on an aft bulkhead of a nacelle inlet where the aft bulkhead does not comprise a spring ring, the method comprising:
 connecting an outer edge of the aft bulkhead to an outer barrel of the nacelle inlet and connecting an inner edge of the aft bulkhead to an inner barrel of the nacelle inlet where the aft bulkhead outer edge is positioned rearwardly of the aft bulkhead inner edge.   
     
     
         19 . The method of  claim 18 , further comprising:
 configuring a rear surface of the aft bulkhead with a concave configuration between the outer edge of the aft bulkhead and the inner edge of the aft bulkhead.   
     
     
         20 . The method of  claim 18 , further comprising:
 configuring a rear surface of the aft bulkhead with a flat configuration that extends between the outer edge of the aft bulkhead and the inner edge of the aft bulkhead.