Abstract: A test blade for use in a blade-release test in which the blade is mounted on a rotatable hub and at least a portion of the blade is released therefrom by the action of a controlled explosion. The blade has a root portion for mounting on said rotatable hub and the root portion comprises a radially inner surface having a channel extending at least partly along or proximal the camber line. The channel is for receiving at least one explosive charge and at least one detonator which may be contained within a charge carrier.

Abstract: A test blade for use in a blade-release test in which the blade is mounted on a rotatable hub and at least a portion of the blade is released therefrom by the action of a controlled explosion. The blade has a root portion for mounting on said rotatable hub and the root portion comprises a radially inner surface having a channel extending at least partly along or proximal the camber line. The channel is for receiving at least one explosive charge and at least one detonator which may be contained within a charge carrier.

Abstract: Percussive impacts due to bird strikes upon the hollow fan blades 20 are a well known problem. These percussive impacts not only deform previous fan blades but also reduce their stiffness. In accordance with the present invention, hollow fan blades 20 incorporate a cavity 23 within which, a matrix 24 with embedded expandable elements 25, is located. Thus, upon a percussive impact these expandable elements 25 are released in order to create an internal pressure within the cavity 25 which acts outwardly in order to relieve deformation and also stiffen the blade 20 as a result of the over pressure within the cavity 23.