Variable-Density Aircraft Structure for Cargo Conversion

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Solution Overview

Problem

Converting a passenger aircraft into a cargo aircraft often requires extensive modifications, leading to shifts in the aircraft's center of gravity due to the removal of components, which complicates loading flexibility and flight characteristics.

Innovation Solution

Implementing a structural element with a varying density gradient along the longitudinal axis of the aircraft, utilizing panels and additional weight components to shift the center of gravity towards the rear, maintaining cargo volume and flight stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If components are removed from the aircraft to create loading space for cargo, then cargo volume is improved, but the center of gravity shifts which worsens flight characteristics

Engineering Contradiction:
Improvecargo volumeVSAvoidcenter of gravity position
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating a density gradient within the structural element, where different regions have different densities. The rear portion of the structural element has higher density than the front portion, which compensates for the center of gravity shift caused by removing passenger components. This localized variation in density allows the structural element to simultaneously maintain structural integrity and adjust the aircraft's center of gravity position.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the density parameter of the structural element by incorporating a density gradient. The structural element transitions from a uniform density design to a variable density design, where the density increases toward the rear of the aircraft. This parameter change allows the structural element to serve dual functions: maintaining structural strength and adjusting the center of gravity position to compensate for component removal.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the center of gravity is shifted to maintain flight characteristics, then loading flexibility is improved, but additional weight components are required which worsens device complexity

Engineering Contradiction:
Improveloading flexibilityVSAvoidstructural element complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the center of gravity adjustment function with the structural element itself. Instead of adding separate ballast components or weight adjustment devices, the density gradient is integrated directly into the structural element that already provides structural support. This merging eliminates the need for additional complex devices while achieving the desired center of gravity shift for improved loading flexibility.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The structural element is designed to perform multiple functions simultaneously: it provides structural support, maintains aerodynamic integrity, and adjusts the center of gravity position through its density gradient. This multi-functionality reduces the need for separate components, thereby reducing device complexity while improving loading flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4631849A1Aircraft having a primary structure having a structural element with varying density gradient
Publication Date: 2025.10.15 ELBE FLUGZEUGWERKE GMBH
  • EP4631849A1 patent drawingFigure 1~2
  • EP4631849A1 patent drawingFigure 3~5
  • EP4631849A1 patent drawing

AI summary

An aircraft (10) with a primary structure (11) is described. The primary structure (11) has a structural element (20) in the form of a wall and is defined by an extension in three spatial axes (17, 18, 19). The wall is characterized by a density gradient that varies along a longitudinal axis (17) of the primary structure (11) and is designed to displace a center of gravity (50) of the aircraft (10) along the longitudinal axis (17) of the primary structure (11) between a front end (15) and a rear end (16) of the aircraft (10) as a function of the varying density gradient.