Bi-Planar Wing Tip Device Reducing Induced Drag

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Solution Overview

Problem

Aircraft wings experience induced drag due to wing tip vortices, which reduce payload capacity, range, and fuel efficiency, and existing wing tip configurations do not effectively minimize this drag.

Innovation Solution

A wing tip device comprising an upper winglet and a lower element forming a closed loop with a hollow interior, which is removably attachable to the wing, extending upwardly and downwardly to create a configuration that reduces induced drag by increasing the effective length of the wing trailing edge without increasing the wing span.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional wing tip configurations are used, then the wing span remains limited, but induced drag increases and aerodynamic performance deteriorates

Engineering Contradiction:
Improveinduced dragVSAvoidwing tip configuration complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies dimensionality change by transitioning from a conventional single upper winglet configuration to a bi-planar wing tip device with both upper and lower elements arranged in vertical layers. This three-dimensional configuration increases the effective trailing edge length without increasing wing span, thereby reducing induced drag while maintaining a compact structure that does not excessively increase complexity

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

Solution Approach 2:

The lower element is positioned beneath the upper winglet, creating a nested vertical arrangement where the lower component is effectively 'nested' within the vertical space occupied by the upper element. This nesting approach allows both elements to contribute to drag reduction without requiring lateral expansion, thus improving aerodynamic performance without proportionally increasing structural complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

2Loss of energy

If wing span is increased to reduce induced drag, then aerodynamic performance improves, but aircraft structural weight and complexity increase

Engineering Contradiction:
Improveinduced dragVSAvoidaircraft structural weight
Core Design Contradiction:
Loss of energyVSWeight of moving object

Solution Approach 1:

Instead of increasing wing span horizontally, the patent utilizes the vertical dimension by stacking upper and lower elements. This approach achieves the equivalent aerodynamic effect of a longer trailing edge without the weight penalty of extending the wing span, thus reducing induced drag while minimizing additional structural weight

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

Solution Approach 2:

The lower element and upper winglet are designed with thin-walled hollow cross-sections that provide the necessary structural strength to resist aerodynamic loads while minimizing material usage. This thin-walled construction reduces the weight of the wing tip device itself, offsetting some of the additional weight from the bi-planar configuration

Inventive Principle:
Principle #30Flexible shells and thin films

3Loss of energy

If closed loop configuration with hollow interior is used, then tip vortices are minimized and drag reduces, but manufacturing complexity increases

Engineering Contradiction:
Improveinduced dragVSAvoidwing tip device manufacturability
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The wing tip device is segmented into separate upper winglet and lower element components that can be manufactured independently using standard aerospace fabrication processes. This segmentation allows each component to be produced and tested separately, simplifying the manufacturing process while the final assembly creates the beneficial closed-loop hollow configuration that minimizes tip vortices

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lower element and upper winglet are constructed using composite materials with thin-walled hollow cross-sections, which can be manufactured through modern composite fabrication techniques such as autoclave curing or resin transfer molding. These materials provide high strength-to-weight ratio and can be formed into complex curved shapes required for the closed-loop configuration, making the manufacturing process more feasible despite the geometric complexity

Inventive Principle:
Principle #40Composite materials

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 wing tip device reduces induced drag, enhances aerodynamic performance, and improves payload capacity and fuel efficiency by minimizing tip vortices and reducing structural weight and complexity.

Implementation Method 1

The upper winglet and the lower element may have an airfoil cross-section such that the upper winglet and the lower element may generate aerodynamic lift

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 2

The closed loop has a hollow interior to allow air to pass through the closed loop

Methodology Applied
Scientific EffectInduced drag reduction: Vortex Ring

Data Source

PatentEP2930103B1Wing tip device for an aircraft wing
Publication Date: 2021.02.24 THE BOEING CO
  • EP2930103B1 patent drawingFigure 1
  • EP2930103B1 patent drawingFigure 2
  • EP2930103B1 patent drawingFigure 3

AI summary

A wing tip device (300) for an aircraft wing (200) may include an upper winglet (302) and a lower element (398). The upper winglet (302) may extend upwardly from an aircraft wing (200). The lower element (398) may extend downwardly from the upper winglet (302) and may form a closed loop below the wing (200). The closed loop may have a hollow interior.