Perforated Fold Region for Foldable Air Vehicle Fins

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Solution Overview

Problem

Existing foldable flight control members on air vehicles suffer from increased radar cross-section, turbulence, and drag due to discontinuities and protruding hinges, which affect the vehicle's performance and survivability.

Innovation Solution

A foldable moveable member with a sheet comprising a first and second portion connected by a fold region featuring a pattern of holes that form a continuous surface, reducing stiffness and minimizing discontinuities, thereby improving aerodynamics and radar cross-section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a hinge is used to connect the top part and base part of the fin, then the fin can be folded to reduce space, but the hinge creates a discontinuity that increases radar cross-section and causes turbulence and drag

Engineering Contradiction:

Improvespace occupied by the finVSAvoidradar cross-section, turbulence, and drag

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The foldable member is segmented into a first portion, a fold region, and a second portion, where the fold region contains a pattern of holes that allows folding while maintaining surface continuity. This segmentation enables the fin to be folded for compact storage while the patterned fold region prevents radar reflection and turbulence by eliminating the discontinuity created by traditional hinges.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fold region incorporates a pattern of holes creating a porous structure that reduces stiffness to enable folding while maintaining aerodynamic and radar properties. The porous fold region allows the material to bend without creating a hard discontinuity, thus reducing radar cross-section and minimizing turbulence and drag during flight.

Inventive Principle:

Principle #31Porous materials

2Adaptability or versatility

If the fold region stiffness is reduced to enable folding, then the member can be folded, but the structural integrity may be compromised

Engineering Contradiction:

Improvefolding capabilityVSAvoidstructural integrity

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The foldable member has non-uniform stiffness distribution: the fold region contains a pattern of holes that reduces stiffness to enable folding, while the first and second portions maintain full density and high structural integrity. This local quality differentiation allows the member to be folded at the fold region while maintaining overall strength and structural integrity of the fin.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The member is divided into three segments with different stiffness characteristics: the first portion (high stiffness), the fold region (reduced stiffness with hole pattern), and the second portion (high stiffness). This segmentation allows the fold region to provide folding capability while the solid portions maintain structural integrity for load-bearing functions.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12601574B2Foldable moveable member for an air vehicle with fold region having a plurality of holes

Publication Date: 2026.04.14 MBDA UK

AI summary

A foldable moveable member for an air vehicle. The moveable member includes a sheet. The sheet has a first portion, a second portion, and a fold region. The first portion is connected to the second portion via the fold region, and the fold region comprises a plurality of holes such that the stiffness of the fold region is lower than the first or second portion. The fold region, the first portion, and the second portion form a continuous surface.