Composite Rotor Blade Mass Balancing via Liquid Weighting Material
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Solution Overview
Problem
The existing methods for mass balancing of rotor blades using solid metal weights are labor-intensive, require significant time for redesign and fabrication, pose challenges in securely integrating the weights, and often exceed human handling capacity, with large weights necessitating mechanical hoisting and risking dislodgment during operation.
Innovation Solution
Integration of a weighted material, such as dense metal strips or powder, into the composite manufacturing process of rotor blades, allowing for easy modification of mass balance by adjusting the size, location, and density of the weighted portion using fiber placement machines, and sandwiching the weighted material between layers of fiber/resin composite material for secure entrapment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid metal weights are used for mass balancing, then mass balance can be achieved, but manufacturing time and labor increase significantly
Solution Approach 1:
The patent changes the physical state of the weighting material from solid metal weights to liquid weighting material that is injected into cavities. This parameter change allows the material to conform to complex geometries and be distributed precisely where needed, eliminating the need for time-consuming casting and machining operations while achieving the same mass balance function.
Solution Approach 2:
The patent uses a composite approach by combining the liquid weighting material with the rotor blade structure itself. The weighting material is injected into cavities formed within the rotor blade, creating an integrated composite structure where the weight is permanently bonded to the blade, eliminating separate manufacturing steps for producing and installing solid metal weights.
2Reliability
If solid metal weights are used for mass balancing, then desired dynamics can be produced, but redesign and fabrication time increases when changes are needed
Solution Approach 1:
The patent makes the mass balancing system dynamic and adjustable by using liquid weighting material that can be easily injected, removed, or repositioned. This allows for rapid adjustments to mass balance without requiring permanent structural modifications or new tooling, enabling quick adaptation when flight dynamics requirements change.
Solution Approach 2:
The patent incorporates cavities into the rotor blade structure during initial manufacturing, preparing the structure in advance to receive liquid weighting material. This preliminary action eliminates the need for subsequent drilling, tapping, or structural modifications when adjustments are needed, allowing for rapid redesign and reconfiguration.
3Reliability
If large solid metal weights are used for mass balancing, then mass balance can be achieved, but handling becomes difficult beyond human capacity
Solution Approach 1:
The patent divides the weighting function into multiple small cavities distributed throughout the rotor blade structure rather than using one or two large solid weights. Each cavity contains a small amount of liquid weighting material, making the overall system much easier to handle and manipulate during manufacturing and adjustment, while still achieving the required total mass balance.
Solution Approach 2:
The patent uses liquid weighting material that can be injected through fluid delivery systems into the cavities. This hydraulic approach allows the material to be easily transported and positioned without manual handling of heavy components, eliminating the need for mechanical hoisting equipment and making the process fully manageable by human operators.
4Reliability
If solid metal weights are used for mass balancing, then mass balance can be achieved, but secure integration becomes challenging to prevent dislodgment
Solution Approach 1:
The patent merges the weighting material with the rotor blade structure by injecting the liquid material into cavities that are an integral part of the blade. The liquid material bonds to the cavity walls, creating a unified structure where the weight cannot become dislodged. This eliminates the need for separate fastening mechanisms, retaining rings, or other complex integration systems required for solid metal weights.
Solution Approach 2:
The patent changes the physical state of the weighting material from solid to liquid, allowing it to flow into and conform to the cavity geometry. When the liquid material cures or solidifies, it creates a permanent bond with the cavity walls, ensuring secure integration without requiring additional fastening hardware or complex assembly procedures.
Data Source
AI summary
A rotor blade for an aircraft includes a composite portion having fiber-reinforced resin material, the composite portion having an outside surface that forms at least a partial airfoil shape. The weighted portion includes a plurality of weighted material layers and a plurality of fiber-reinforced resin material layers. Weighted material is configured to be compatible with and integrated into composite manufacturing processes used to fabricate the rotor blade. The weighted portion has a higher density than the composite portion and positioned to produce desired mass balance characteristics of the rotor blade.