FABRICATION OF BRAIDED RTM DRIVESHAFT TUBES FOR THE RAH-66 COMANCHE

Kaman is fabricating tail rotor Driveshafts and Quill Shafts for the RAH-66 Comanche. These tubes are all-composite construction, using triaxial graphite fiber (Hercules IM7) and a toughened epoxy (3M PR-500). Several braiding problems were resolved, including accurately modeling ply thickness for large triaxial tows, determining a method for nesting braided plies, and effecting a smooth transition from a braid pattern of 0/+60° to 0/+45° on a tapering mandrel with full fiber coverage. Both shafts utilize Resin Transfer Molding (RTM) to fill the dry preform with PR-500. The RTM process for fabricating each tube is discussed along with difficulties encountered, their solutions, and the final RTM process parameters.