Open Rotor Blade Pitch Offset to Reduce 1P Loading

The patent applies asymmetric blade pitch scheduling where the pitch of rotor blades varies asymmetrically during rotation. The pitch schedule is defined such that blades at different circumferential positions have different pitch angles, with maximum pitch at one circumferential position and minimum pitch at another position offset by a specific angle from the pitch axis. This asymmetry in pitch distribution mitigates 1P loading while optimizing thrust efficiency, resolving the contradiction between control simplicity and thrust efficiency.

The patent implements periodic pitch adjustment where the blade pitch follows a predetermined schedule that repeats each rotation cycle. The pitch varies periodically with the angular position of the blades, following a defined pattern that includes maximum pitch at a first circumferential position and minimum pitch at a second circumferential position. This periodic action achieves 1P loading mitigation and thrust optimization through systematic pitch variation without requiring overly complex real-time control systems.

The patent optimizes the offset angle parameter between the reference line and pitch axis to balance control complexity and 1P loading mitigation effectiveness. By carefully selecting the offset angle within a specific range, the system achieves effective 1P loading reduction while maintaining manageable pitch control complexity. This parameter optimization resolves the contradiction between simplifying pitch control and improving 1P loading mitigation effectiveness.