Improvements in or relating to gas-turbine engines

907,884. Valves. ROLLS-ROYCE Ltd. May 4, 1960 [May 19, 1959], No. 17046/59. Addition to 843,479. Class 135. [Also in Group XXVI] In a gas turbine engine as claimed in the parent Specification in which, on failure of the driving shaft with consequent relative rotation between the turbine and driven member, the fuel supply to the engine is reduced, the fuel supply means includes a valve having a frangible diaphragm 36 interconnecting fixed and movable elements of the valve and holding the valve open, and a spring 29 urging the movable element to a closed setting, the diaphragm 36 being fractured by a load applied by a cable 38, of the control means on shaft failure. The valve body 10 has a spring housing unit comprising a cylinder 24 and an end plate 26 having an aperture registering with a central bore 11. The movable element of the valve comprises a bolt 31 carrying a sleeve 27 and a cup member 28. The diaphragm 36 may be of aluminium and it will withstand loads applied by the spring 29 and any spring tensioning the cable 38, but will be sheared when the cable is jerked by the safety device. This movement is assisted by the spring 29 which also holds the valve in the " failed " position. With the movable valve element in the normal position, any fuel leaking along the sleeve 27 collects in a space 34 and then flows in a clearance between the bolt 31 and the sleeve 27 through holes 41 into the cylinder 24 then through holes 42 to a drain through aperture 43.