Magnetic Hold-Down for Flight Control Surfaces

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Solution Overview

Problem

Aircraft flight control surfaces experience constant aerodynamic lift forces during cruise, leading to fatigue and high maintenance requirements for actuators, particularly hydraulic ones, as they continuously counteract these forces to maintain the surfaces in a neutral position, which can result in sub-optimal performance.

Innovation Solution

The implementation of magnetic hold-down assemblies using magnets and ferromagnetic structures to counteract aerodynamic lift forces, keeping flight control surfaces in a stowed position during flight, thereby reducing the load on actuators and extending their service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic actuators are used to counteract aerodynamic lift force, then the flight control surface can be maintained in neutral position, but the actuators experience continuous fatigue and require frequent maintenance

Engineering Contradiction:

Improveactuator service lifeVSAvoidcontinuous actuator operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the continuous mechanical/hydraulic actuation system with a magnetic field-based holding system. Magnets positioned in the neutral position generate a magnetic force that counteracts the aerodynamic lift force, eliminating the need for continuous hydraulic actuator operation and reducing fatigue-related maintenance requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary force between the aerodynamic lift and the flight control surface. The magnetic field acts as a mediator that balances the aerodynamic forces without requiring direct mechanical contact or continuous actuator engagement, thereby reducing wear on the actuator components.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If non-hydraulic actuators are used, then fatigue issues are avoided, but the device complexity increases and performance may be sub-optimal

Engineering Contradiction:

Improveactuator fatigue resistanceVSAvoidactuator system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent substitutes complex mechanical actuation systems with a simpler magnetic field-based system. By using permanent magnets positioned in the neutral position, the system achieves reliable force counteraction without the complexity of hydraulic or pneumatic actuation mechanisms, thereby reducing device complexity while maintaining reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of energy

If the flight control surface is maintained in neutral position during cruise, then drag is minimized, but the actuator components experience continuous fatigue

Engineering Contradiction:

Improveaerodynamic dragVSAvoidactuator service life

Core Design Contradiction:

Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The patent replaces continuous mechanical actuation with a static magnetic field configuration. Magnets positioned in the neutral position create a persistent magnetic force that maintains the flight control surface in the optimal neutral position without requiring continuous actuator operation, thereby eliminating fatigue while preserving the drag-minimizing neutral position.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution effectively maintains flight control surfaces in a stowed position during cruise, reducing the load on actuators and minimizing fatigue, thus enhancing their service life and reducing maintenance needs, particularly for hydraulic actuators.

Implementation Method 1

One of the flight control surface or the adjacent structure comprises at least one magnet and the other of the flight control surface or the adjacent structure comprises at least one ferromagnetic structure. An interaction of a magnetic field of the at least one magnet with the at least one ferromagnetic structure causes a magnetic force that urges the flight control surface toward a stowed position.

Methodology Applied

Scientific EffectMagnetic field interaction: Magnetic Field

Implementation Method 2

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentUS11926416B1Flight control systems and related methods of magnetically counteracting aerodynamic lift forces on flight control surfaces

Publication Date: 2024.03.12 THE BOEING CO

AI summary

Methods comprise flying an aircraft at cruise which results in an aerodynamic lift force on a flight control surface of the aircraft that urges the flight control surface away from a stowed position. Concurrently with the flying, the methods include counteracting the aerodynamic lift force with a magnetic force that urges the flight control surface towards the stowed position and that results in the flight control surface being maintained in the stowed position during the flying. Flight control systems comprise a flight control surface and an adjacent structure. The flight control surface or the adjacent structure comprises a magnet and the other of the flight control surface or the adjacent structure comprises a ferromagnetic structure. A magnetic force urges the flight control surface toward a stowed position.