Elastomeric Riblets for Aircraft Drag Reduction
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Solution Overview
Problem
Existing aerodynamic riblet structures on aircraft surfaces, made from polymeric materials, lack durability and are prone to deformation and damage from environmental and operational stresses, including interactions with chemicals like Skydrol, which limits their practicality for commercial use.
Innovation Solution
The use of high elongation elastomeric materials with tips and a surface layer, combined with a supporting polymer layer and optional cladding, to create riblets that can withstand deformation and maintain structural integrity, featuring a range of polymers and fillers for enhanced durability and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If polymeric materials are used for riblet structures, then aerodynamic drag reduction is achieved, but durability and resistance to deformation are significantly reduced
Solution Approach 1:
The patent changes the material parameter from conventional thermoplastic or thermoset polymers to high elongation elastomeric materials with elongation capability of 300-3000%. This parameter change enables the riblets to withstand hundreds of percent deformation and recover, resolving the contradiction between maintaining aerodynamic performance and improving durability
Solution Approach 2:
The patent employs composite material structures including elastomeric polymers combined with fillers (titanium dioxide, diamond powder, POSS), and optionally with protective cladding layers (parylene, PTFE, metal coatings). These composite structures provide both the aerodynamic drag reduction of riblet geometry and the durability/chemical resistance required for practical application
2Loss of energy
If polymeric materials are used for riblet structures, then aerodynamic drag reduction is achieved, but resistance to chemical exposure is insufficient
Solution Approach 1:
The patent uses composite material structures including elastomeric polymers combined with fillers (titanium dioxide, diamond powder, POSS), and optionally with protective cladding layers (parylene, PTFE, metal coatings). These composite structures provide both the aerodynamic drag reduction of riblet geometry and the durability/chemical resistance required for practical application
3Ease of manufacture
If conventional polymeric riblets are used, then manufacturing is simplified, but structural integrity under stress is compromised
Solution Approach 1:
The patent changes the material parameter from conventional thermoplastic or thermoset polymers to high elongation elastomeric materials with elongation capability of 300-3000%. This parameter change enables the riblets to withstand hundreds of percent deformation and recover, resolving the contradiction between maintaining aerodynamic performance and improving durability
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 high elongation elastomeric riblets provide increased durability and resistance to deformation, allowing for thinner, lighter, and more aerodynamically efficient structures that can withstand various impacts and chemical exposures, while maintaining aerodynamic performance and appearance.
Implementation Method 1
The high elongation elastomeric material has capability for elongation of 300 - 3000%
Data Source
Figure 1
Figure 2A~2D
Figure 2E~2G
AI summary
An array of aerodynamic riblets incorporates a high elongation elastomeric layer (201) having spaced tips (202) and optionally a protective cladding. The elastomeric layer may be adhered to an aerodynamic surface directly or as an appliqué in combination with one or more of an adhesive layer, one or more supporting polymer layers (208) and a metal foil layer (220).