MATERIAL APPLICATIONS TO A LIGHT HELICOPTER

Bell Helicopter Textron is developing configurations and structure applicable to light helicopters using composite materials with goals of 20% weight and cost savings over aluminum construction. The concept was to make large composite parts of simple laminates using a single cure step. "Large" was clarified as a part weighing more than 4 lb. Prior work had clearly shown that the cost of small parts in composites is excessive. Skins, longerons, bulkheads, and spar lose their identity as they are integrated into these large laminated parts. Standardized material forms using minimum-gage skin together with constant section longerons, stiffeners, and beam caps were used. IML vs. OML tooling was based upon next assembly mating requirements for each component. Recesses in the tool surface provided for location of stringers, longerons, and cut outs. The roof, being the most heavily loaded component, was selected for the first structural demonstration. Both the target manufacturing labor rate and design strength were demonstrated. This effort substantiated that a light helicopter composite airframe structure can be competitive with metal construction.