The present invention relates to the manufacture of aerofoil blades of the kind used in ducted fan gas turbine engines, wherein the aerofoils are located via respective roots, in and about the rim of a rotary disk within a ducted fan gas turbine engine.
More specifically, the present invention has best efficacy where used in the manufacture of gas turbine engine fan blades, the aerofoils of which are hollow.
It is known to manufacture a hollow fan blade by forming two half aerofoils, one of which provides a concave exterior surface, and the other of which provides a convex exterior surface, and both include a half root portion. The formed halves are then placed in a die and heated so as to enable diffusion bonding of the halves and super-plastic expansion and separation in known manner of the interior surfaces of the joined aerofoils to cause movement of the aerofoils into their respective curved forms.