Lifting Foil With Flow Guides For Induced Drag Reduction

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Solution Overview

Problem

Aircrafts experience significant energy losses due to induced drag, primarily caused by vortices shed from wing tips, which existing techniques have not fully addressed, leading to inefficiencies in flight and increased operational costs.

Innovation Solution

A lifting foil design featuring a horizontal upper course, a parallel and spaced lower course, and vertically extending flow guides that balance pressure at the margins, reducing spanwise fluid flow and vortex generation, thereby minimizing drag and enhancing stability and lift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional wing designs are used, then aircraft can achieve basic lift, but significant energy losses occur due to induced drag from wing tip vortices

Engineering Contradiction:

Improveinduced dragVSAvoidvortex formation

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The wing is divided into an upper course and a lower course that are spaced apart, with flow guides connecting them. This segmentation disrupts the continuous spanwise flow that creates vortices, thereby reducing induced drag and energy loss while maintaining lift generation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces a vertical dimension by spacing the upper and lower courses apart and using vertically extending flow guides. This three-dimensional configuration prevents the two-dimensional spanwise flow that leads to vortex formation, reducing induced drag without compromising lift.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If wing tip modifications are made to reduce vortices, then induced drag decreases, but structural complexity increases

Engineering Contradiction:

Improveinduced dragVSAvoidfoil structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The flow guides serve multiple functions: they connect the upper and lower courses structurally, guide fluid flow to balance pressure between courses, and prevent vortex formation. This multi-functionality reduces induced drag without proportionally increasing structural complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The flow guides are designed to balance pressure between the upper and lower courses at their margins, creating equipotential conditions that eliminate the pressure differential driving spanwise flow and vortex formation, thereby reducing induced drag with minimal structural addition.

Inventive Principle:

Principle #12Equipotentiality

3Loss of energy

If pressure balancing is achieved at foil margins, then spanwise flow and vortex generation are reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improveinduced dragVSAvoidmargin blending

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The flow guides are designed with specific cross-sectional parameters that enable pressure balancing. By carefully controlling the cross-sectional geometry of the flow guides, the invention achieves pressure equilibrium at the margins, reducing spanwise flow and induced drag while maintaining feasible manufacturing tolerances.

Inventive Principle:

Principle #35Parameter changes

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 design significantly reduces induced drag, increases lift, and improves aircraft stability, particularly at low speeds, by minimizing vortex formation and optimizing fluid flow around the wing tips.

Implementation Method 1

a span-wise flow of air from a relatively high pressure condition on the lower wing surface to a relatively low pressure condition on the upper wing surface

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

The region between the first and second surfaces defines a cambered lifting body which reacts to the dynamic pressure on its first and second surfaces by generating a net upwardly directed lifting force

Methodology Applied

Scientific EffectBernoulli effect: Bernoulli Effect

Implementation Method 3

there is diminished generation of initial spanwise fluid flow by balancing the pressure at the upper starboard margin against the pressure at the lower starboard margin, and concomitantly balancing the pressure at the upper port margin against the pressure at the lower port margin

Methodology Applied

Scientific EffectPressure balancing:

Implementation Method 4

The lifting foil can include a third surface for dividing the large central passage into a pair of smaller, spaced apart, passages having generally elliptical cross-sections and a fuselage can be formed therewith

Methodology Applied

Scientific EffectNewton's third law:

Data Source

PatentUS9976421B2Lifting foil

Publication Date: 2018.05.22 HOUCK II RONALD G

AI summary

A lifting foil having a configuration with a leading course and trailing course which is rotated about an axis of rotation into a fluid.