Wingtip Turbulence Features Reduce Download Forces

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Solution Overview

Problem

Vertical takeoff and landing aircraft face challenges in reducing download forces during hovering, which can lead to increased drag and energy consumption, limiting their efficiency and versatility.

Innovation Solution

The implementation of wingtips with contoured outboard faces and turbulence features, such as surface roughness, trip strips, or vortex generators, to induce turbulence and promote lift, reducing the download force by managing rotor downwash and minimizing pressure drag.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If vertical takeoff and landing aircraft hover using a vertical rotor, then vertical lift capability is achieved, but download forces increase leading to higher drag and energy consumption

Engineering Contradiction:

Improvedownload forceVSAvoidenergy consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful rotor downwash (which creates download forces and drag) into a beneficial force by directing it across the outboard face of the wingtip. The downwash that would otherwise be wasted is now used to generate wingtip lift, reducing the net download force and thereby decreasing energy consumption during hovering

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the physical parameters of the wingtip by introducing turbulence features (such as vortex generators or surface roughness elements) that modify the flow characteristics of the rotor downwash. These parameter changes induce turbulence that enhances mixing and promotes lift generation on the outboard face, effectively reducing download forces

Inventive Principle:

Principle #35Parameter changes

2Force

If rotor downwash is directed downward for vertical lift, then hovering capability is maintained, but pressure drag increases

Engineering Contradiction:

Improvevertical liftVSAvoidpressure drag

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful pressure drag caused by rotor downwash into a beneficial effect. By directing the downwash across the outboard face of the wingtip, the previously harmful flow becomes a source of wingtip lift that counteracts the download force, thereby reducing the net pressure drag on the aircraft

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The wingtip outboard face acts as an intermediary element between the rotor downwash and the aircraft body. It redirects and utilizes the downwash flow to generate lift, serving as a mediator that transforms the harmful downward flow into a useful lateral flow that reduces drag

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

This design effectively reduces download forces, enhancing the aircraft's hovering efficiency and reducing energy consumption, while maintaining performance in forward flight.

Implementation Method 1

a turbulence feature located on the wingtip and oriented to induce turbulence in the rotor downwash flowing across the outboard face

Methodology Applied

Scientific EffectTurbulence: Turbulence

Implementation Method 2

an outboard face of the wingtip contoured to promote wingtip lift in response to the rotor downwash flowing across the outboard face

Methodology Applied

Scientific EffectAerodynamic lift: Aerofoil

Data Source

PatentUS12017754B2Download reducing wingtips

Publication Date: 2024.06.25 TEXTRON INNOVATIONS INC

AI summary

An aircraft includes a wing positioned below a vertical rotor, the wing extending in a transverse direction to a wingtip having an outboard face, and a turbulence feature located on the wingtip and oriented to induce turbulence in the rotor downwash flowing across the outboard face in a direction from a top surface of the wing to a bottom surface of the wing.