Rotating Airfoil Assembly with Tilted Rotation Axis
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Solution Overview
Problem
Rotating airfoils in aircraft engines, such as fan blades or propellers, experience asymmetric loading during aircraft pitch changes, leading to cyclic loading conditions that can cause fatigue stresses and strains.
Innovation Solution
The rotation axis of the rotating airfoil assembly is aligned with the airflow, or the angle of attack is reduced, by actively rotating the airfoils or the entire engine to maintain perpendicular airflow, thereby reducing or eliminating asymmetric loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the aircraft pitch changes during flight, then the aircraft can perform maneuvers and change flight path, but the rotating airfoils experience asymmetric loading causing fatigue stresses and strains
Solution Approach 1:
The patent makes the rotation axis of the airfoil assembly movable relative to the aircraft body, allowing it to dynamically adjust its orientation. During pitch changes, the rotation axis can tilt to remain perpendicular to the airflow direction, ensuring that all airfoils experience symmetric loading conditions regardless of aircraft attitude, thereby eliminating fatigue stresses while maintaining full maneuverability
2Device complexity
If the rotation axis is fixed relative to the aircraft body, then the engine structure is simple and stable, but asymmetric loading occurs during pitch changes
Solution Approach 1:
The rotation axis is designed to be dynamically adjustable rather than fixed. The axis can tilt relative to the aircraft body using actuation mechanisms, allowing it to maintain perpendicular orientation to the airflow during pitch changes. This dynamic adjustment eliminates asymmetric loading on the airfoils while the overall engine structure remains relatively simple through controlled mobility
3Object-affected harmful factors
If the airfoils are actively rotated to align with airflow, then asymmetric loads are reduced, but the system complexity and energy consumption increase
Solution Approach 1:
The patent combines the rotation axis adjustment function with the existing engine mounting structure. The rotation axis is integrated into the engine pylon or mounting system, allowing it to tilt as a unified structure rather than requiring separate actuation mechanisms for each airfoil. This merging approach reduces system complexity while effectively eliminating asymmetric loads through coordinated rotation of the entire airfoil assembly
Data Source
AI summary
An engine for an aircraft. The engine includes a rotating airfoil assembly, at least one actuator, a torque producing system, and a controller. The rotating airfoil assembly includes a rotation axis and a plurality of rotating airfoils configured to rotate about the rotation axis in a plane of rotation. The at least one actuator is operable to change the plane of rotation of the plurality of rotating airfoils. The torque producing system is coupled to the rotating airfoil assembly and configured to rotate the rotating airfoil assembly about the rotation axis of the rotating airfoil assembly. The controller is configured to determine that the aircraft has an angle of attack and to operate the at least one actuator to change the plane of rotation of the plurality of rotating airfoils based on the angle of attack.