Movable Aircraft Ballast Docks for CG Envelope Adjustment

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Solution Overview

Problem

Aircraft face challenges in maintaining the center of gravity (CG) within a desirable envelope due to changes from loading and unloading passengers and cargo, requiring adjustments that are often impractical or impossible with existing ballast systems, especially when temporary ballast is not readily available at destination locations.

Innovation Solution

A movable ballast system with fore and aft ballast docks allows for the selective placement of ballasts to adjust the CG, using unique dimensioned ballasts that can be easily moved between docks to counteract shifts in the CG, and a flight control computer calculates the necessary adjustments to maintain optimal CG positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fixed ballasts are used to manipulate the CG of the aircraft, then the CG can be adjusted to remain within the desired envelope, but the system lacks adaptability when flight conditions change and requires certified mechanics for installation or removal

Engineering Contradiction:
ImproveCG control reliabilityVSAvoidballast adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The ballast system is segmented into multiple individual ballast units that can be independently installed or removed from the aircraft structure. Each ballast unit can be placed in different locations (forebody, midbody, aftbody) to provide flexible CG adjustment. This segmentation allows the pilot to quickly reconfigure the ballast system without requiring mechanical work, resolving the contradiction between reliability and adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ballast system transitions from a static fixed configuration to a dynamic reconfigurable system. The ballast units can be added or removed based on changing flight conditions, passenger loads, and cargo configurations. This dynamic capability allows the aircraft to maintain optimal CG across multiple mission scenarios without requiring permanent installation or removal of ballast by certified mechanics.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If temporary ballast such as sandbags or water jugs is added to alter the CG, then the CG can be adjusted for specific flights, but the system becomes cumbersome and reduces cargo capacity

Engineering Contradiction:
Improveballast flexibilityVSAvoidballast system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention extracts the essential ballast function from cumbersome temporary solutions like sandbags and water jugs. By providing dedicated ballast units with integrated mounting features, the system separates the ballast weight from the cargo space, allowing temporary ballast effects without the complexity and space consumption of ad-hoc solutions. The ballast units are specifically designed for aircraft integration, eliminating the need to use cargo space for ballast.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ballast system uses simple, lightweight ballast units that can be easily added or removed for each flight mission. These units are designed to be temporary in nature - installed when needed for specific flight conditions and removed when not needed, similar to disposable solutions but with proper aircraft integration. This approach provides the flexibility of temporary ballast without the complexity of unsecured sandbags or water jugs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If the aircraft carries temporary ballast from the first location to the second location, then the CG can be maintained for the return flight, but the ballast occupies valuable cargo weight and volume capacity

Engineering Contradiction:
ImproveCG envelope maintenanceVSAvoidcargo capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The ballast units are designed as universal components that serve multiple functions: they provide CG adjustment for different flight scenarios, can be positioned in multiple locations along the aircraft fuselage, and can be used in combination with each other or independently. This multi-functionality allows the same ballast units to address various CG issues without requiring separate ballast for each scenario, maximizing cargo capacity while maintaining CG control.

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

Solution Approach 2:

The system allows dynamic changes in ballast parameters including total ballast weight, ballast distribution across different locations, and individual ballast unit positions. By adjusting these parameters, the aircraft can optimize CG for different mission profiles while minimizing the total ballast weight required, thereby preserving maximum cargo capacity. The flight control computer helps calculate optimal parameter configurations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3786059B1System and method for adjustable ballast
Publication Date: 2021.10.20 TEXTRON INNOVATIONS INC
  • EP3786059B1 patent drawingFigure 1
  • EP3786059B1 patent drawingFigure 2
  • EP3786059B1 patent drawingFigure 3~4

AI summary

A method of adjusting a center of gravity (CG) of an aircraft includes: inputting at least one load parameter into a flight computer, determining, via a processer of the flight computer, the CG of the aircraft. Responsive to a determination by the processor that the CG is outside of a CG envelope, moving at least a first movable ballast of a plurality of movable ballasts from a first ballast dock to a second ballast dock to move the CG toward the CG envelope. Each of the first and second ballast docks may include a housing and a first ballast tray secured within the housing and comprising a plurality of channels.