Rotor Fairing Seal Assembly for Drag Reduction and Access
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Solution Overview
Problem
Conventional fairings in rotorcraft rotor systems fail to adequately reduce aerodynamic drag, particularly in high-speed flight conditions, leading to significant power and efficiency penalties.
Innovation Solution
A fairing system with a hub fairing and a fixed fairing arranged about a rotation axis, featuring a seal assembly with a seal race, seal member, and seal member housing, which includes an annulus portion and resilient flange portion, allowing for remountable fairings and reduced aerodynamic drag by sealing gaps between rotor system components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional fairings are used in rotorcraft rotor systems, then the structure is simple and easy to manufacture, but the aerodynamic drag is significantly high leading to power and efficiency penalties
Solution Approach 1:
The fairing system is divided into multiple segments: a hub fairing portion, a fixed fairing portion, and a seal assembly. This segmentation allows each component to be optimized independently for aerodynamic performance while maintaining overall system functionality. The hub fairing and fixed fairing can be separately manufactured and assembled, reducing manufacturing complexity despite the improved aerodynamic design.
Solution Approach 2:
The seal assembly is nested within the gap between the hub fairing and fixed fairing, creating a compact integrated structure. The seal member fits within the seal race, and the resilient flange portion is contained within the seal member housing. This nesting approach allows complex sealing functionality to be incorporated without proportionally increasing overall system complexity.
2Ease of repair
If fairings are made removable for maintenance access, then ease of repair is improved, but sealing effectiveness between moving and static components deteriorates
Solution Approach 1:
The fairing system is segmented such that the hub fairing and fixed fairing can be independently removed from the seal assembly. This allows maintenance personnel to access components within the fairings without disturbing the seal assembly, maintaining sealing effectiveness while improving ease of repair. The seal assembly remains intact and mounted to the support structure during fairing removal.
Solution Approach 2:
The seal assembly is extracted from the fairing structure and mounted independently to the support structure. This extraction allows the fairings to be removed for maintenance without affecting the seal assembly, which remains in place to maintain sealing effectiveness between the rotor system and pylon.
3Loss of energy
If a seal assembly is added between hub fairing and fixed fairing, then aerodynamic drag is reduced by sealing gaps, but device complexity increases
Solution Approach 1:
The seal member includes a resilient flange portion made of flexible material that can deform to maintain sealing contact between the hub fairing and fixed fairing. This flexible element effectively seals the gap to reduce aerodynamic drag while maintaining a relatively simple seal assembly structure that does not require complex mechanical components.
4Reliability
If the seal member includes a resilient flange portion, then sealing reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The seal member incorporates a resilient flange portion that changes its physical state from rigid to flexible, allowing it to compensate for manufacturing tolerances and wear. The resiliency of the flange portion enables it to maintain sealing contact despite variations in manufacturing precision, achieving reliable sealing without requiring extremely tight manufacturing tolerances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fairing system effectively reduces aerodynamic drag and facilitates easy installation and maintenance by maintaining a consistent seal between moving and static components, enhancing the lift-to-drag coefficient and overall efficiency of rotorcraft.
Implementation Method 1
The seal member can include an annulus portion connected to a resilient flange portion. The resilient flange portion can extend radially relative to the rotation axis... The sealing face can be in mechanical contact with the resilient flange about the rotation axis
Data Source
AI summary
A fairing system, includes a hub fairing and a fixed fairing, such as a shaft fairing or a pylon fairing, both arranged about a rotation axis. A gap is defined between the hub fairing and the fixed fairing, and a seal assembly is axially interposed between the hub fairing and the fixed fairing. The fixed fairing and the hub fairing are both removably mounted to the seal assembly such that either or both of the fairings can be dismounted from the seal assembly without disturbing the seal assembly to provide access to components disposed within the fairing.