DESIGN, DEVELOPMENT, AND FABRICATION OF THE MODEL 430 BEARINGLESS MAIN ROTOR YOKE

The Model 430 rotorcraft represents the next generation Bell intermediate twin helicopter. It incorporates numerous improvements over existing designs. Most notable of these is the bearingless main rotor system. This paper will give a brief overview of the Model 430 development program from inception through first flight, with specific emphasis on the main rotor system, particularly the main rotor yoke. The yoke was identified as the component critical to the enabling technology for the bearingless rotor concept. This paper will present significant detail on the evolution of the concept; critical element design, tooling, and fabrication and testing; and production component design, tooling, and fabrication for the main rotor yoke. Particular attention will be paid to the elements that presented technical, manufacturing, and tooling risks. Incorporation of the results of the risk reduction efforts into the production design will also be presented.