Aircraft Lifting Surface Parametric Design
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Solution Overview
Problem
Current methods for designing aircraft airfoils require a large number of parameters to define complex surfaces, leading to increased dimensionality, resource-intensive geometric CAD models, and lack of smoothness in curvature or tangency continuity.
Innovation Solution
A method that segregates parameters into independent spanwise functions, allowing for the definition of key features by specifying only relevant points along the span, reducing the number of data required to define the airfoil geometry and minimizing storage and computation resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional methods with multiple control sections are used to define complex airfoil surfaces, then the geometric precision and completeness of the surface definition is improved, but the number of parameters and dimensionality of the parameter space increases vastly
Solution Approach 1:
The patent segments the airfoil surface definition into two independent parts: (1) a set of control sections that define the spanwise geometry, and (2) a separate lofting function that interpolates between these sections to create the continuous surface. This segmentation allows precise surface definition without requiring parameters for every possible surface point, thus reducing parameter space dimensionality while maintaining manufacturing precision.
Solution Approach 2:
The patent introduces a lofting function as an intermediary mathematical tool that connects the discrete control sections to the continuous airfoil surface. This intermediary function automatically generates the intermediate surface geometry, eliminating the need to explicitly define every parameter and reducing the overall parameter space dimensionality while maintaining surface precision.
2Manufacturing precision
If more control sections are added to define discontinuities in tangency, then the accuracy of representing complex geometric features is improved, but the geometric CAD model becomes heavier and requires more storage and computing resources
Solution Approach 1:
The patent uses mathematical functions (lofting functions) to generate the continuous surface geometry as a computational copy rather than storing explicit data for every surface point. This allows accurate representation of complex features including discontinuities while minimizing data storage requirements, as only the control sections and lofting function parameters need to be stored.
Solution Approach 2:
The patent changes the parameterization strategy from storing explicit geometric data for numerous control sections to using a compact mathematical representation with fewer parameters. By transforming the problem from discrete point storage to continuous function evaluation, the method reduces data quantity while maintaining the ability to accurately represent complex geometric features.
3Area of stationary object
If traditional interpolation schemes are used between control sections, then the completeness of surface coverage is improved, but the smoothness and continuity of curvature and tangency on the designed surfaces deteriorates
Solution Approach 1:
The patent changes the interpolation method from traditional schemes to carefully selected mathematical lofting functions that inherently maintain continuity of position, tangency, and curvature. By selecting appropriate mathematical functions with sufficient continuity properties, the patent achieves complete surface coverage while ensuring smooth transitions and continuous curvature across the entire airfoil surface.
Data Source
AI summary
A method of designing an external geometry of an aircraft lifting surface, including the steps of defining a geometric shape corresponding to an initial lifting surface according to a planform, wherein the initial lifting surface is defined by at least five geometry parameters and a plurality of shape modifier parameters of the lifting surface, modifying the geometric shape of the initial lifting surface by applying a spanwise function to a shape modifier parameter of the initial lifting surface to obtain a modified lifting surface, defining a thickness of an airfoil at a given span position along the span of the modified lifting surface obtained in the modifying step based on a predefined airfoil, and defining the external geometry of the aircraft final lifting surface by interpolating the airfoil along the span of the modified lifting surface via a transition function.