Abstract: A hollow fan blade for turbo fan gas turbine engines is formed of two separate detail halves. Each detail half has a plurality of cavities and ribs machined out to reduce weight. These detail halves are subsequently bonded and given an airfoil shape in the forming operation. The present invention provides a hollow fan blade with internal cavity and rib geometry with improved durability that permits the bonding and forming to be performed without the need for gas pressurization. The ability to form the hollow fan blade of the present invention without gas pressurization is a result of the cavity and rib geometry and the orientation of the ribs. The ribs are tapered and transition into a compound radius of the floor that simulates the classical arch design element. The orientation of the ribs is generally in a parallel plane with the load vector that results from forming loads during the pre-form and final form operations.

Abstract: Hollow fan blades for turbo fan gas turbine engines are formed of two separate detail halves. Each detail half has a plurality of cavities and ribs machined out to reduce weight. These detail halves are subsequently bonded and given an airfoil shape in the forming operation. In the present invention, the ribs are oriented biased to provide stiffness as needed in different sections of the fan blade with smooth transitions between regions. The result is a blade with good protection from a wide spectrum of external threats.

Abstract: Hollow fan blades for turbo fan gas turbine engines are formed of two separate detail halves. Each detail half has a plurality of cavities and ribs machined out to reduce weight. These detail halves are subsequently bonded and given an airfoil shape in the forming operation. In one embodiment, contiguous cavities are formed around freestanding ends of the ribs to reduce the number of cavities required. The freestanding end of each rib is flared such that it has a larger width than the rest of the rib. The cavity extends continuously around the free, flared end of the rib.