Variable-Span VTOL Wing Layout to Minimize Propeller Wake Interaction

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Solution Overview

Problem

Existing VTOL aircraft suffer from aerodynamic interactions between propellers and fixed wing planes, leading to performance degradation, increased size, and limited ability to operate in confined spaces due to the need for multiple propellers and fixed wing adaptations, which also complicates weight and compactness.

Innovation Solution

Aircraft design with foldable wings and strategically positioned propellers to minimize aerodynamic interactions, using a variable-span main wing plane and dual contra-rotating propellers to reduce propeller wakes and mechanical stresses, allowing for compactness and efficient flight phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple propellers are used for lift in electric motor VTOL aircraft, then take-off power and flight safety are improved, but aerodynamic interaction phenomena increase and aircraft performance deteriorates

Engineering Contradiction:

Improveflight safetyVSAvoidaircraft performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The aircraft uses four separate lift propellers distributed on either side of the fuselage, each independently connected to the fixed part of the wing. This segmentation allows for redundancy (improving reliability) while the strategic positioning minimizes aerodynamic interactions between propellers (preserving performance)

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The propellers are positioned at specific locations with precise longitudinal and lateral spacing. The longitudinal separation of at least one chord magnitude and lateral separation of at least one fuselage width creates local zones where aerodynamic interactions are minimized, allowing each propeller to operate more independently

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple propellers are used for lift, then flight safety is improved, but aircraft length and width dimensions increase

Engineering Contradiction:

Improveflight safetyVSAvoidaircraft size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The main wing plane has a variable span capability, allowing the wings to be folded along the lateral axis. During vertical take-off and landing, the reduced span configuration minimizes the aircraft's lateral dimensions, enabling operation in confined areas while maintaining four propellers for safety

Inventive Principle:

Principle #15Dynamics

3Force

If fixed wing planes and propellers are used simultaneously, then lifting capability is improved, but aerodynamic interaction between wakes increases

Engineering Contradiction:

Improvelifting capabilityVSAvoidaerodynamic interaction

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The fixed wing planes are positioned above the propellers in the vertical direction, and the propellers are positioned downstream of the wing leading edges. This preliminary spatial arrangement ensures that propeller wakes do not interact with the wing surfaces, preventing harmful aerodynamic interactions while maintaining both lifting capabilities

Inventive Principle:

Principle #10Preliminary action

4Volume of moving object

If propellers are positioned close to fixed wing planes, then aircraft compactness is improved, but aerodynamic interaction increases

Engineering Contradiction:

Improveaircraft compactnessVSAvoidaerodynamic interaction

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The design establishes specific local spacing requirements: longitudinal separation of at least one chord magnitude and lateral separation of at least one fuselage width. These localized spacing zones minimize aerodynamic interactions while the overall aircraft remains compact through efficient spatial arrangement and variable span wings

Inventive Principle:

Principle #3Local quality

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 reduces aerodynamic interactions, enhances flight performance, and enables operation in confined areas by minimizing propeller wakes and overall size, improving safety and efficiency.

Implementation Method 1

four lift propellers... ensure lift of the apparatus during take-off and vertical landing

Methodology Applied

Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 2

folding of the movable end part of each wing above the fixed part of the wing reduces effects of aerodynamic interaction with the propellers

Methodology Applied

Scientific EffectAerodynamic drag reduction: Drag

Data Source

PatentUS12559234B2Vertical take-off and landing aircraft

Publication Date: 2026.02.24 OFFICE NAT DETUDES & DE RECH AEROSPATIALES

AI summary

A vertical take-off and landing aircraft includes a fuselage, at least one propulsion system, at least four lift propellers and at least two fixed wing planes. The fixed wing planes which are located behind the most forward lift propellers are located above the lift propellers. The lift propellers are distributed on either side of at least one of the fixed wing planes and on either side of the fuselage such that the lift propellers are longitudinally separated by at least the magnitude of the chord of the fixed wing plane located therebetween, and are laterally separated by at least the width of the fuselage located therebetween. At least one of the fixed wing planes has a variable span and the aircraft includes a control system for varying this span in flight.