Retractable Aircraft Wing Tip Flexible Lifting Envelope

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Solution Overview

Problem

Aircraft efficiency improvements through increased wingspan are limited by airport gate restrictions and structural weight increases due to rigid winglets and raked wing tips, which require costly modifications and do not effectively alleviate gate compatibility issues.

Innovation Solution

Retractable aircraft wing tips with a flexible lifting envelope that inflate to increase wingspan during flight and deflate for ground parking, using a telescoping or rolled configuration to minimize structural modifications and weight, allowing for dynamic adjustment of wingspan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rigid winglets or raked wing tips are added to increase wingspan, then aerodynamic efficiency is improved, but structural weight increases and gate compatibility is compromised

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidstructural weight

Core Design Contradiction:

ProductivityVSWeight of moving object

Solution Approach 1:

The wing tip structure is made dynamically adjustable through inflation and deflation of the lifting envelope, allowing the wingspan to be extended during flight for improved aerodynamic efficiency and retracted during ground operations to maintain gate compatibility and reduce structural weight requirements

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The physical state of the lifting envelope is changed between inflated and deflated states to alter the wingspan parameter, enabling the aircraft to transition between different operational configurations without permanent structural modifications

Inventive Principle:

Principle #35Parameter changes

2Productivity

If rigid winglets or raked wing tips are added to increase wingspan, then aerodynamic efficiency is improved, but airport gate compatibility deteriorates

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidgate compatibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The wing tip is segmented into a retractable lifting envelope portion that can be independently deployed or retracted, separating the aerodynamic function from the ground operation constraints and allowing flexible adaptation to different gate requirements

Inventive Principle:

Principle #1Segmentation

3Productivity

If rigid winglets or raked wing tips are added to increase wingspan, then aerodynamic efficiency is improved, but structural reinforcement requirements increase

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidstructural reinforcement requirements

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The lifting envelope is constructed as a flexible structure that derives its structural support from internal inflation pressure rather than rigid reinforcement, reducing the complexity of structural improvements needed in the wing while still providing the necessary aerodynamic surface

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The lifting envelope uses internal air pressure to provide structural support and maintain its shape during flight, replacing the need for complex rigid structural reinforcement and reducing the overall structural complexity required to accommodate increased wingspan

Inventive Principle:

Principle #29Pneumatics and hydraulics

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

Enhances fuel efficiency by reducing induced drag without requiring airport gate modifications or significant structural changes, offering weight savings and flexibility in gate compatibility, while maintaining lift-producing capabilities.

Implementation Method 1

This lifting envelope may inflate from a stowed configuration to an extended configuration that produces lift when air is provided inside the lifting envelope

Methodology Applied

Scientific EffectInflation:

Implementation Method 2

the lifting envelope may deflate and retract to the stowed configuration when the internal air is released

Methodology Applied

Scientific EffectDeflation:

Implementation Method 3

the retractable aircraft wing tip may include a telescoping spar within the flexible lifting envelope that extends outward from the end of the aircraft wing when air is introduced into the lifting envelope

Methodology Applied

Scientific EffectTelescoping:

Implementation Method 4

the retractable wing tip may include a flexible spar within a flexible lifting envelope that is biased in a rolled-up configuration. When air is introduced into the flexible lifting envelope, the flexible spar unrolls outward from the aircraft wing as the lifting envelope inflates

Methodology Applied

Scientific EffectFlexible deformation: Elasticity

Data Source

PatentUS8336830B2Retractable aircraft wing tip

Publication Date: 2012.12.25 THE BOEING CO

AI summary

Apparatus and methods provide for the use of retractable aircraft wing tips to increase the wingspan of an aircraft to decrease drag and increase fuel efficiency. According to various embodiments, a flexible lifting envelope is attached to an outboard end of an aircraft wing. Upon receiving pressurized air, the flexible lifting envelope extends outward to a lift-producing configuration that extends the span of the aircraft wing to which it is attached. When deflated, the flexible lifting envelope retracts into a stowed configuration to decrease the wingspan of the aircraft to allow for parking at airport gates or to alleviate flight loads. Various implementations provide for a telescoping wing tip and for a rolled wing tip.