Aircraft noise reduction apparatus

Abstract

An aircraft, aircraft landing gear and apparatus including at least one attachment ( 15,17,76,93,94,111 ) for noise reduction purposes are provided. Such attachments are shaped and positioned on the landing gear to deflect air away from noise-inducing components ( 64,65 ) of the landing gear and to permit deflection and articulation movement and also stowage of the landing gear whilst the attachments are installed thereon. The attachments are not designed to be drag-reducing.

1 . Aircraft noise reduction apparatus including at least one noise-reducing attachment ( 15 , 17 , 76 , 93 , 94 , 111 ) for landing gear of the aircraft shaped for positioning on the landing gear to deflect air away from noise inducing components of the landing gear and to permit deflection, articulation movement and stowage of the landing gear with the attachment installed.  
     
     
         2 . Apparatus as in  claim 1  in which a said attachment comprises a deflector screen ( 15 , 17 , 76 , 93 , 94 , 111 ) adapted not to completely surround noise inducing components on the landing gear.  
     
     
         3 . Apparatus as in  claim 1  or  2  in which the attachment comprises an axle attachment ( 15 ) positionable in front of an axle ( 3 ) for nose gear of the aircraft.  
     
     
         4 . Apparatus as in  claim 3  in which the axle attachment is shaped to enclose a towbar fitting ( 24 ).  
     
     
         5 . Apparatus as in  claim 3  or  4  in which the axle attachment includes generally cylindrical wheel extensions ( 30 , 31 ) extending between a central portion ( 32 ) thereof and each wheel ( 33 ).  
     
     
         6 . Apparatus as in  claim 1  or  2  in which the attachment comprises a steering mechanism attachment ( 17 ) for positioning in front of a steering mechanism for the landing gear.  
     
     
         7 . Apparatus as in  claim 1  or  2  including an apertured strut attachment ( 16 ) positionable over a said aperture ( 40 ) in the strut ( 14 ) to deflect air away from edges ( 41 , 42 ) of the aperture.  
     
     
         8 . Apparatus as in  claim 7  in which the attachment ( 16 ) is shaped to blend in airflow leaving the attachment with airflow passing over streamwise extending surfaces ( 45 , 46 ) of the strut, when in use.  
     
     
         9 . Apparatus as in  claim 7  or  8  in which the attachment ( 16 ) is shaped to deflect air away from noise-inducing elements on the landing gear positioned to the rear of the said strut ( 14 ).  
     
     
         10 . Apparatus as in any preceding claim in which the attachment ( 15 , 17 , 76 , 93 , 94 , 111 ) is shaped to avoid regions of air stagnation thereover, when in use.  
     
     
         11 . Apparatus as in any preceding claim including an undertray attachment ( 76 ) shaped to extend in front of and underneath a bogie beam ( 71 ) of the landing gear.  
     
     
         12 . Apparatus as in  claim 11  in which the undertray ( 76 ) includes a forward upwardly extending aerodynamic surface ( 82 ) blended smoothly into an undersurface ( 83 ) extending underneath and along the bogie beam with a further laterally facing surface extending longitudinally of the bogie beam on either side of the undertray ( 89 , 90 ) depending from lateral edges ( 87 , 88 ) of the undertray.  
     
     
         13 . Apparatus as in  claim 11  or  12  in which the undertray ( 76 ) is attachable to axles ( 72 , 73 ) on the landing gear bogie by means of band-type clamps ( 79 , 80 ) adapted to pass around the axle/bogie beam and through at least one part-annular chamber ( 99 , 100 ) formed in an extension piece fixed to the undertray.  
     
     
         14 . Apparatus as in any preceding claim including a pair of articulating fairing attachments ( 93 , 94 ) for attachment to a forward articulation link ( 67 , 68 ) of a bogie of the landing gear, one articulated fairing being mounted to each articulation link with an aerodynamically contoured interface ( 105 ) being defined between the fairings comprising a generally spherical element ( 106 ) on one fairing ( 94 ) co-operating with generally circular section ( 107 ) tubing of the other fairing ( 93 ).  
     
     
         15 . Apparatus as in  claim 14  when dependent upon any one of  claims 11  to  13  in which the undertray ( 76 ) and lower articulation link fairing ( 93 ) in use lie closely adjacent one another with the landing gear bogie ( 71 ) in its approach-to-landing configuration.  
     
     
         16 . Apparatus as in any preceding claim including a door attachment ( 111 ) attachable to a door ( 112 ) which is attached to the landing gear, the door extending generally streamwise to one side of the landing gear, the door attachment ( 111 ) being positionable to extend from the door in front of at least a main leg ( 64 ) of the landing gear.  
     
     
         17 . Apparatus as in  claim 16  in which the door attachment ( 111 ) is adapted for sealing engagement with the door ( 112 ).  
     
     
         18 . Aircraft landing gear including apparatus according to any preceding claim.  
     
     
         19 . Aircraft landing gear as in  claim 18  in which at least one said attachment is shaped and positioned such that airflow over the attachment ( 16 ) during flight leaves the attachment substantially in the free steam direction.  
     
     
         20 . Aircraft landing gear as in  claim 18  or  19  in which at least one said attachment ( 111 ) is positioned to deflect incident air away from an air accelerating region formed between two components ( 64 , 65 ) of the landing gear.  
     
     
         21 . Aircraft including landing gear according to any of  claims 18  to  20 .