Duct Vane Rotation System Structural Hoop Guide Rails
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Solution Overview
Problem
Ducted-rotor aircraft systems face challenges in efficiently translating the rotation of control vanes for tiltrotor aircraft between helicopter and airplane modes, requiring a mechanism to restrict movement while allowing vane rotation, to optimize space and functionality.
Innovation Solution
A duct vane rotation system utilizing a structural hoop connected to control vanes with spherical bearings, an idler to restrict forward-aft movement, and a torque tube with bell crank mechanisms to translate motion, allowing ±25 degrees rotation about a hinge line axis while preventing hoop rotation and maintaining space within the duct center body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the structural hoop is allowed to move freely, then the control vanes can rotate easily, but the hoop will have uncontrolled forward-aft and side-to-side movement that interferes with duct operations
Solution Approach 1:
Guide rails are introduced as intermediary elements between the structural hoop and the duct ring. These guide rails constrain the hoop's movement to a specific rotational path while allowing free rotation of the control vanes. The guide rails act as mediators that permit the desired rotational motion while preventing unwanted forward-aft and side-to-side movements.
2Adaptability or versatility
If the structural hoop rotation is not restricted, then the system has more flexibility, but the hoop may rotate about the hinge line axis causing interference with duct center body operations
Solution Approach 1:
The rotational degree of freedom about the hinge line axis is extracted or removed from the structural hoop's motion capabilities. By designing the guide rails to constrain movement to a specific rotational path perpendicular to the hinge line, the system eliminates the harmful rotational motion while preserving the necessary flexibility for mode conversion operations.
3Adaptability or versatility
If more space is allocated for structural hoop movement, then the vane rotation range increases, but the available space in the duct center body is reduced
Solution Approach 1:
The guide rails are positioned and oriented to constrain the structural hoop's movement to a rotational path that operates in a dimension perpendicular to the duct center body's primary space requirements. This dimensional arrangement allows the vanes to achieve the necessary rotation range while minimizing encroachment on the duct center body volume, as the hoop's movement is confined to a specific rotational trajectory rather than occupying additional radial or axial space.
Data Source
AI summary
One embodiment is a rotor system comprising a duct ring; a hub disposed centrally to the duct ring; first and second stators each connected between the duct ring and the hub; first and second control vanes rotatably connected to the first and second stators, respectively; a structural hoop having a first end connected to the first control vane and a second end connected to the second control vane, the structural hoop for translating rotation of the first control vane about a vane axis to the second control vane; and a mechanism for restricting at least one of forward-aft movement and side-to-side movement of the structural hoop relative to the duct ring.