Embedded engines in hybrid blended wing body

Abstract

A hybrid wing aircraft has an engine embedded into a body of the hybrid wing aircraft. The embedded engine has a fan that is received within a nacelle. The body of the aircraft provides a boundary layer over a circumferential portion of a fan. A system delivers additional air to correct fan stability issues raised by the boundary layer.

1 . A hybrid wing aircraft comprising:
 an engine embedded into a body of said hybrid wing aircraft, such that said embedded engine has a fan received within a nacelle, and wherein said body providing a boundary layer over a circumferential portion of a circumference of said fan; and   a system to deliver additional air to correct fan stability issues raised by said boundary layer.   
     
     
         2 . The hybrid wing aircraft as set forth in  claim 1 , wherein said system includes a tap for providing additional airflow into a location of said boundary layer upstream of said fan. 
     
     
         3 . The hybrid wing aircraft as set forth in  claim 2 , wherein said tap includes a tap from a compressor which is downstream of said fan. 
     
     
         4 . The hybrid wing aircraft as set forth in  claim 2 , wherein said tap includes a tap in said body and further upstream of said fan than an outlet of said tap, such that said tap provides additional airflow into said boundary layer. 
     
     
         5 . The hybrid wing aircraft as set forth in  claim 4 , further comprising a plurality of axially spaced taps delivering air to a plurality of axially spaced outlets. 
     
     
         6 . The hybrid wing aircraft as set forth in  claim 2 , wherein there are a plurality of circumferentially spaced outlets. 
     
     
         7 . The hybrid wing aircraft as set forth in  claim 1 , wherein said system provides additional air to a location downstream of said fan. 
     
     
         8 . The hybrid wing aircraft as set forth in  claim 7 , wherein said system delivering air into a position downstream of said fan at a location spaced from said circumferential portion of said boundary layer, such that the delivered air drives additional air to said location of said boundary layer. 
     
     
         9 . The hybrid wing aircraft as set forth in  claim 1 , further comprising a valve controlled to control the amount of additional air delivered. 
     
     
         10 . The hybrid wing aircraft as set forth in  claim 1 , further comprising a nozzle on said nacelle downstream of said fan, and said nozzle being moveable to address fan conditions when an approaching stall condition may be detected. 
     
     
         11 . The hybrid wing aircraft as set forth in  claim 10 , wherein said variable area nozzle is moved to a more open position when stall is detected. 
     
     
         12 . The hybrid wing aircraft as set forth in  claim 1 , further comprising a moveable portion of said body positioned upstream of said fan and which may be moved away from a rotational envelope of said fan to minimize said boundary layer under certain conditions. 
     
     
         13 . The hybrid wing aircraft as set forth in  claim 1 , wherein an estimate of said boundary layer conditions under any number of flight conditions is initially made, and stored with a controller and said controller being operable to control said system to address fan stability issues under various flight conditions. 
     
     
         14 . A method of operating a hybrid wing aircraft comprising:
 operating an embedded engine embedded into a body of a hybrid wing aircraft, such that said embedded engine has a fan received within a nacelle, and wherein said body providing a boundary layer over a circumferential portion of a circumference of said fan; and   delivering additional air to correct fan stability issues raised by said boundary layer.   
     
     
         15 . The method as set forth in  claim 14 , further comprising delivering additional airflow into a location of said boundary layer upstream of said fan. 
     
     
         16 . The method as set forth in  claim 15 , wherein said additional air is tapped from a location in said body further upstream of said fan than an outlet of said tap, such that said tap provides additional airflow into said boundary layer. 
     
     
         17 . The method as set forth in  claim 14 , further comprising supplying said additional air to a location downstream of said fan. 
     
     
         18 . The method as set forth in  claim 17 , further comprising delivering said additional air into a position downstream of said fan at a location spaced from the circumferential location of said boundary layer, such that the additional air drives air to the location of said boundary layer. 
     
     
         19 . The method as set forth in  claim 14 , further comprising positioning a nozzle on said nacelle downstream of said fan, and said nozzle moved to a more open position when stall is detected. 
     
     
         20 . The method as set forth in  claim 14 , further comprising positioning a moveable portion of said body upstream of said fan and moved away from a rotational envelope of said fan to minimize said boundary layer under certain conditions. 
     
     
         21 . The method as set forth in  claim 14 , further comprising estimating said boundary layer conditions under any number of flight conditions initially, and storing within a controller and controlling the system with a controller to address potential stall under various flight conditions.