Lightweight Rigid Rotor Blade with Transitional Brace Folding
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Solution Overview
Problem
Conventional blade folding systems in rotary-wing aircraft are cumbersome and susceptible to drag, limiting their efficiency and utility, especially in environments where space is limited and rapid deployment is required.
Innovation Solution
A rotor blade assembly with a first section mounted to the rotor hub, a second section with a flexbeam, and a transitional brace that moves between positions to allow the second section to pivot about a blade axis, enabling folding without removing fairings or other components, and using fasteners to secure the brace in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional blade folding systems are used to reduce structural envelope, then the aircraft can be stored in limited space, but the systems are cumbersome and susceptible to drag decreasing flight efficiency
Solution Approach 1:
The transitional brace is designed to be movable between a first position (during folding) and a second position (during flight), allowing the system to dynamically adapt its configuration. This resolves the contradiction by enabling the blade to achieve a compact folded state when needed while maintaining an aerodynamically efficient configuration during flight, thus reducing structural envelope without permanently compromising flight efficiency
Solution Approach 2:
The rotor blade is divided into a first section (inboard) and a second section (outboard), connected by a rotatable coupling mechanism. This segmentation allows independent movement of the second section relative to the first, enabling the blade to fold without requiring complex conventional folding systems that compromise aerodynamics. The segmented design achieves compact storage while maintaining flight efficiency through simpler, cleaner joints
2Productivity
If conventional blade folding systems are used to reduce structural envelope, then rapid deployment becomes possible, but the systems become cumbersome increasing device complexity
Solution Approach 1:
The rotor blade is divided into a first section (inboard) and a second section (outboard), connected by a rotatable coupling mechanism. This segmentation allows independent movement of the second section relative to the first, enabling the blade to fold without requiring complex conventional folding systems that compromise aerodynamics. The segmented design achieves compact storage while maintaining flight efficiency through simpler, cleaner joints
Solution Approach 2:
The transitional brace is designed to be movable between a first position (during folding) and a second position (during flight), allowing the system to dynamically adapt its configuration. This resolves the contradiction by enabling the blade to achieve a compact folded state when needed while maintaining an aerodynamically efficient configuration during flight, thus reducing structural envelope without permanently compromising flight efficiency
Data Source
AI summary
A rotor blade rotated about a rotor hub is provided including a first section configured to mount to the rotor hub. The first section includes a spindle and an inboard torque tube surrounding a portion of the spindle. A second section of the rotor blade includes a flexbeam and an outboard torque tube attached to and surrounding the flexbeam. An inboard end of the flexbeam is rotatable coupled to a first end of the spindle. The second section is configured to rotate about a blade axis between an aligned position and a rotated position. A transitional brace configured to surround a portion of the rotor blade adjacent the coupled flexbeam and spindle is movable between a first position and a second position. When in the first position, the transitional brace limits movement of the second section about the blade axis.