Patent ID: 7357166

Claim:
An aircraft stringer lay-up assembly comprising: a contoured curing block; a first mandrel element positioned on said contoured curing block, said first mandrel element comprises: an elongated beam having a plurality of rigidity reducing first slots formed along a first mandrel length, said plurality of rigidity reducing first slots protruding partially through a first mandrel depth of said first mandrel element to allow said elongated beam to conform to said contoured curing block; a central bore chamber formed in said elongated beam along said first mandrel length; and a center support wire positioned through said central bore chamber, said center support wire controlling flexibility of said elongated beam; and a composite ply assembly laid up onto said first mandrel element, said composite ply assembly cured onto said first mandrel element while conformed to said contoured curing block such that a contoured composite stringer element is generated.