Abstract: A compressor disc includes a diaphragm portion connected to a mounting disc portion at its distal end and a cob portion at its proximal end. The cob portion having a leading edge with a shoulder section connected to an end section at Point X, and a trailing edge with a shoulder section connected to an end section at point Y, and a base. The cob portion is asymmetrical about a centreline that extends along a plane representing the geometric centre of the diaphragm portion and through to the base of the cob portion, dividing the diaphragm and cob portion into two respective cob sections, which have surface areas that differ by no more than 10%. The distance between the base of the cob portion and Point X of the leading edge may differ from the distance between the base of the cob portion and Point Y of the trailing edge.

Abstract: A compressor disc includes a diaphragm portion connected to a mounting disc portion at its distal end and a cob portion at its proximal end. The cob portion having a leading edge with a shoulder section connected to an edge section at point X, a trailing edge with a shoulder section connected to an end section at point Y, and a base. Point X is offset relative to point Y in relation to the distance to the cob portion base. Point X of the cob portion may be offset relative to Point Y of the cob portion by 1 to 10 mm. Alternatively Point X of the cob portion is offset relative to point Y of the cob portion by 2 to 8 mm. the cob portion may have asymmetric widths relative to a centreline extending through a plane at the centre of the diaphragm and through into the cob.

Abstract: A fan is mounted on a fan shaft which constitutes part of a mainline shaft assembly centered for rotation on an engine axis X-X of a gas turbine engine. When in operation, the fan rotates about the engine axis X-X. A stub-shaft is arranged radially outwardly and concentrically with the fan shaft and adjoins an upstream facing face of a bearing sleeve. A fan catcher arm extends from the stub-shaft through the bearing sleeve and joins a fan catcher ring arranged downstream of the bearing sleeve and having an upstream facing face arranged to abut against a downstream facing face of the bearing sleeve in the event of a fan blade-off. Immediately downstream of the fan catcher ring is formed a shaft end which is configured to couple with an axially adjacent end of a low pressure compressor shaft. Immediately downstream of the bearing sleeve is a shaft end configured to connect with a turbine shaft.