Advanced Design Concepts for High Performance Helicopter Masts

This proposal is for development of novel concepts and technology for design and processing of enhanced performance titanium matrix composite (TMC) helicopter masts. Such masts will be capable of drop-in replacement, be highly resistant to corrosion and stress corrosion cracking, have high fatigue capability, be lighter weight, have capability for higher operational requirements, and be affordable. In one concept, the mast consists of a titanium planetary end and a TMC body that extends into a titanium region joining with the rotor/blade housing. In another, the mast consists of a titanium planetary end, a TMC body, a short monolithic titanium zone, a bimetal joint section and a nickel-alloy or steel spline end. Others expand on these. The proposed effort builds on TMC aircraft-engine shaft development/demonstrations and extends this for payoff on helicopter masts. The use of corrosion resistant high strength, high stiffness, TMC architectures and possibly advanced bimetal joining offers the potential for enhanced performance masts. The proposed program will accomplish system designs, trade studies, subelement fabrication/technical experiments and establish feasibility of potential mast designs. Phase II will build and test helicopter mast prototypes to verify manufacturing feasibility and perform static testing to demonstrate functional properties.