Abstract:
Modifications are being made to the CH-47 Drive System in order to increase power capacity and lower operating costs. In addition to designing in capacity improvements to the CH-47 Drive System, Boeing is investigating weight reduction technologies for the CH-47F Block II Program. One opportunity is focused on advancing the Manufacturing Readiness Level (MRL) and Technology Readiness Level (TRL) of a Fiber-Reinforced Polymer (Composite) Section of the Chinook's Aft Rotor Shaft. The Composite Section is calculated to save over 50 pounds in the Aft Section of the aircraft. The Hybrid Steel/Composite Aft Rotor Shaft Development was split into a phased program to advance the MRL and TRL while keeping program risk low. Early phases defined component requirements and developed a preliminary ply table to validate weight predictions. The development then moved into manufacturability studies, revising the preliminary ply table and fabricating and inspecting a Half-Length Composite Shaft (Half-Shaft). As the design matures, future phases will encompass full-scale shaft fabrication and risk-reduction and qualification tests. This paper summarizes the interim design considerations of a full-scale hybrid composite shaft and fabrication and inspection of a thick-walled composite tube to develop the technology.