This study proposes a preliminary design procedure for the drive system of a coaxial rotorcraft, incorporating a comprehensive three-dimensional vibratory analysis. In a coaxial rotor, the drive system is required to accommodate kinematic complexity while enabling the counter-rotation of the upper and lower rotors under significantly elevated load conditions. Consequently, the design process becomes a critical and technically demanding task. This study adopts the drive hardware of the Sikorsky X2 Technology Demonstrator—an aircraft smaller than a midsized rotorcraft to be analyzed—as a baseline. This system features a two-stage planetary gear. Subsequently, detailed sizing of gears and bearings is conducted by focusing on the evaluation of their static load safety and the fatigue life of vibratory components for a larger, midsized aircraft. The final three-dimensional configuration of the drive system is established to ensure proper interaction and contact between all relevant components, thereby supporting reliable and efficient operation. A structural analysis is conducted to assess the structural robustness of the drive system under the worst-case operating condition, including an estimation of its fatigue life using damage accumulation. Based on the predicted vibratory behavior, the initial design is further optimized to reduce the overall weight of the drive system.
Preliminary Design of a Drive System for a Midsized Coaxial Rotorcraft
Journal of Aircraft ; 1-9
2025-06-06
Article (Journal)
Electronic Resource
English
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