Gas turbine engine casing

Abstract

An annular fan casing of a gas turbine engine includes a plurality of fan track liner panels, secured to the radially inner surface of the fan casing. The panels are secured using mechanical fasteners, which are secured into non-load-bearing regions of the fan casing so as not to compromise the load-carrying or containment functions of the fan casing.

1 . A casing for a gas turbine engine, the casing comprising a generally cylindrical or frustoconical annulus, at least one liner panel being positioned radially inward of the casing, the or each liner panel being removably securable on the casing by at least one mechanical fastener which in use passes through the liner panel, characterised in that the or each mechanical fastener is not secured to the annulus of the casing.  
   
   
       2 . A casing as in  claim 1 , in which the annulus has a first flange and a second flange axially spaced apart, and in which in use the annulus provides a load path at least between the first flange and the second flange.  
   
   
       3 . A casing as in  claim 2 , in which the or each mechanical fastener is not secured to the annulus of the casing between the first flange and the second flange.  
   
   
       4 . A casing as in any preceding claim, in which the annulus forms part of a containment system.  
   
   
       5 . A casing as in any preceding claim, in which the casing further comprises a member extending generally radially inwards from the annulus, and in which in use at least one mechanical fastener is secured to the member.  
   
   
       6 . A casing as in any of  claims 1  to  4 , in which the casing further comprises a first member and a second member each extending generally radially inwards from the annulus, the first and second members being axially spaced apart.  
   
   
       7 . A casing as in  claim 6 , in which in use at least one mechanical fastener is secured to at least one of the first and second members.  
   
   
       8 . A casing as in  claim 6 , in which the or each liner panel comprises at least one hook, and in which in use at least one mechanical fastener is secured to either the first or the second member, and the hook or hooks engage with the other of the first and second members.  
   
   
       9 . A casing as in  claim 8 , in which a seal is provided between the hook or hooks and the member with which the hook or hooks engage.  
   
   
       10 . A casing as in  claim 9 , in which the seal is an O-ring seal.  
   
   
       11 . A casing as in any of  claims 8  to  10 , in which the hook or hooks include at least one anti-rotation feature which in use engages with a corresponding feature on the casing.  
   
   
       12 . A casing as in any preceding claim, in which a layer of sealant is provided on at least part of the radially outer surface of the or each liner panel, to inhibit fretting and vibration.  
   
   
       13 . A casing as in  claim 12 , in which the sealant is a polysulphide.  
   
   
       14 . A casing as in any preceding claim, in which the or each mechanical fastener is a threaded fastener.  
   
   
       15 . A casing for a gas turbine engine substantially as described in this specification, with reference to and as shown in FIGS.  2  to  13  of the accompanying drawings.