Spanwise Slat Actuation Using a Bell-Crank in Thin Wings

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Solution Overview

Problem

As aircraft wings become thinner to reduce drag, it becomes challenging to accommodate linear hydraulic slat actuators, leading to limited actuator displacement and the need for penetrations in the front spar web.

Innovation Solution

A spanwise-oriented linear hydraulic slat actuator utilizing a bell-crank mechanism to achieve variable output displacement, allowing the actuator to be oriented along the aircraft wing while bypassing the need for front spar web penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the aircraft wing is made thinner to reduce drag, then drag is decreased, but it becomes difficult to accommodate linear hydraulic slat actuators and their displacement is limited

Engineering Contradiction:
ImprovedragVSAvoidactuator displacement
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent reorients the linear hydraulic slat actuator from a chordwise orientation to a spanwise orientation along the aircraft wing. This dimensional change allows the actuator to utilize the spanwise space within the thinner wing structure, achieving sufficient displacement without requiring chordwise penetration of the front spar web.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of moving object

If the linear hydraulic slat actuator is oriented spanwise along the aircraft wing, then greater displacement is achieved within the wing architecture, but the actuator mechanism becomes more complex

Engineering Contradiction:
Improveactuator displacementVSAvoidactuator mechanism
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent introduces a bell-crank mechanism as an intermediary between the spanwise-oriented linear hydraulic slat actuator and the slat. The bell-crank converts the spanwise movement of the actuator into chordwise movement of the slat, enabling the actuator to achieve greater displacement while maintaining a relatively simple hydraulic actuator design.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution enables greater displacement of the slat within the aircraft wing architecture while occupying less space, allowing for more efficient packaging and operation of the slat actuator.

Implementation Method 1

linear hydraulic slat actuator

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

bell-crank is coupled to the linear hydraulic slat actuator and to the actuator output link. In response to spanwise movement of the linear hydraulic slat actuator, the bell-crank is configured to move the actuator output link in a different direction

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP4520658A1Variable slat displacement using spanwise actuator
Publication Date: 2025.03.12 THE BOEING CO
  • EP4520658A1 patent drawingFigure 1
  • EP4520658A1 patent drawingFigure 2
  • EP4520658A1 patent drawingFigure 3

AI summary

An aircraft wing (700) includes a fixed structure (102) and a linear hydraulic slat actuator (104) attached to the fixed structure (102). The linear hydraulic slat actuator (104) is oriented spanwise along the aircraft wing (700). The aircraft wing (700) also includes an actuator output link (108) and a slat (710) attached to the actuator output link (108). The aircraft wing (700) also includes a bell-crank (106) coupled to the linear hydraulic slat actuator (104) and to the actuator output link (108). In response to spanwise movement of the linear hydraulic slat actuator (104), the bell-crank (106) is configured to move the actuator output link (108) in a different direction that enables the slat (710) to move between a retracted position and an extended position.