Windage shield

Abstract

A fan rotor module for a gas turbine engine, the fan rotor module comprising a drive arm, a fan disc and a windage shield attached at one or more points to a rear portion of the fan disc, wherein the fan rotor module comprises at least one balancing weight disposed at one or more of the points where the windage shield is attached to the rear portion of the fan disc.

We claim: 
     
         1 . A fan rotor module for a gas turbine engine, the fan rotor module comprising a drive arm, a fan disc and a windage shield attached at one or more points to a rear portion of the fan disc, wherein the fan rotor module comprises at least one balancing weight disposed at one or more of the points where the windage shield is attached to the rear portion of the fan disc. 
     
     
         2 . The fan rotor module of  claim 1 , wherein one or more balancing weights are disposed at each of the points where the windage shield is attached to the rear portion of the fan disc. 
     
     
         3 . The fan rotor module of  claim 1 , wherein the balancing weights each comprise one or more discrete bodies. 
     
     
         4 . The fan rotor module of  claim 3 , wherein each discrete body has a known mass. 
     
     
         5 . The fan rotor module of  claim 1 , wherein the windage shield is attached to the rear portion of the fan disc by at least one mechanical fixing means. 
     
     
         6 . The fan rotor module of  claim 5 , wherein one or more of the mechanical fixing means comprises a nut and a bolt. 
     
     
         7 . The fan rotor module of  claim 6 , wherein one or more balancing weights each comprise one or more washers disposed on the bolt(s). 
     
     
         8 . The fan rotor module of  claim 1 , wherein the drive arm is a forward facing drive arm or a rearward facing drive arm. 
     
     
         9 . A gas turbine engine including the fan rotor module of  claim 1 . 
     
     
         10 . An aircraft including the gas turbine engine of  claim 9 . 
     
     
         11 . A method of rear-plane balancing of a fan rotor module for a gas turbine engine, the fan rotor module having a drive arm, a fan disc and a windage shield attached at one or more points to a rear portion of the fan disc, the method comprising:
 applying at least one balancing weight at one or more of the points where the windage shield is attached to the rear portion of the fan disc.   
     
     
         12 . The method of  claim 11 , further comprising applying one or more balancing weights at each of the points where the windage shield is attached to the rear portion of the fan disc. 
     
     
         13 . The method of  claim 11 , wherein the balancing weights each comprise one or more discrete bodies. 
     
     
         14 . The method of  claim 13 , wherein the balancing weights are varied by varying the number of discrete bodies. 
     
     
         15 . The method of  claim 11 , wherein the windage shield is attached to the rear portion of the fan disc by at least one mechanical fixing means. 
     
     
         16 . The method of  claim 15 , wherein one or more of the mechanical fixing means comprises a nut and a bolt. 
     
     
         17 . The method of  claim 16 , wherein one or more balancing weights each comprise one or more washers disposed on the bolt(s). 
     
     
         18 . The method of  claim 10 , wherein the drive arm is a forward facing drive arm or a rearward facing drive arm.