Rotary-Wing Attachment Interface With Recessed Ball Stud Mount

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Solution Overview

Problem

Existing attachment interfaces for rotary-wing aircrafts face challenges in efficiently securing external devices while minimizing weight, complexity, and avoiding protrusions that interfere with other equipment, particularly in scenarios like emergency floatation balloons, and require corrosion-resistant, easily repairable, and cost-effective solutions.

Innovation Solution

A rotary-wing aircraft with an attachment interface comprising an interface cap and a ball stud, where the ball stud is partially or fully housed within the airframe inner volume, allowing oblique load introduction into the airframe skin without protrusions, using composite materials to minimize weight and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If ball studs are used for attachment interfaces in rotary-wing aircraft, then easy releasable connection and free rotation are achieved, but protrusions interfere with external equipment and corrosion resistance becomes problematic

Engineering Contradiction:

Improvereleasable connectionVSAvoidinterference with external equipment

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The ball stud is nested within a recess in the airframe skin, with the ball portion contained within the skin thickness. This nesting approach allows the attachment interface to provide releasable connection functionality while eliminating protrusions that would interfere with external equipment such as floatation balloons.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The problematic protruding portions of the ball stud are extracted or removed from the external surface. The ball stud is designed to be embedded within the airframe skin, taking out the interference issue while retaining the essential ball joint functionality for releasable connections.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If ball studs are fixed into sandwich shell, then attachment strength is achieved, but corrosion resistance and repairability are limited

Engineering Contradiction:

Improveattachment strengthVSAvoidrepairability

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The attachment interface is segmented into separate components: the ball stud, the recess, and the floatation balloon attachment structure. This segmentation allows the ball stud to be replaced or repaired independently without replacing the entire airframe skin or sandwich shell structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The attachment interface is designed to be dynamic and adaptable. The ball stud can be removed and reinstalled, and the recess can accommodate different attachment configurations. This dynamic design enhances repairability compared to fixed, permanent attachments.

Inventive Principle:

Principle #15Dynamics

3Strength

If additional reinforcement members are added to reduce bending load, then structural strength is improved, but weight and device complexity increase

Engineering Contradiction:

Improvestructural strengthVSAvoidcomplexity of fixation

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

Instead of adding global reinforcement members throughout the airframe, the design uses local quality enhancement by creating a recess specifically at the attachment location. This localized structural modification provides the necessary bending load resistance only where needed, without adding unnecessary weight or complexity elsewhere in the structure.

Inventive Principle:

Principle #3Local quality

4Weight of moving object

If thin composite sandwich shells are used for airframe skin, then weight is reduced, but resistance to pulling loads and peeling failures decreases

Engineering Contradiction:

Improveairframe weightVSAvoidresistance to peeling failures

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The attachment interface transitions from a surface-level attachment to a three-dimensional recessed structure. By creating a recess that extends into the sandwich shell thickness, the attachment gains additional dimensional space to distribute loads more effectively, reducing peeling stresses on the thin composite face sheets while maintaining the lightweight advantage.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS20250333187A1Rotary-wing aircraft with at least one attachment interface

Publication Date: 2025.10.30 AIRBUS HELICOPTERS DEUT GMBH

AI summary

A rotary-wing aircraft, comprising: an airframe with an airframe skin that forms an outer airframe loft line and encloses an airframe inner volume, wherein the airframe skin comprises at least one airframe opening; and at least one attachment interface that is mounted to the airframe skin at the airframe opening and configured for a releasable attachment of an external device, wherein the at least one attachment interface comprises an interface cap with a mounting flange that is rigidly attached to the airframe skin, wherein the interface cap comprises at least one pocket that forms a pocket base; and a ball stud with a stud shaft and a ball, wherein the ball stud is rigidly attached to the pocket base and extends at least partly into the airframe opening.