Inclined Rotor Thrust Unit with Movable Shrouding

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Solution Overview

Problem

Conventional multirotor aircraft thrust producing units with ducts or shrouds are inefficient in transversal air flow conditions, leading to increased drag and power requirements during forward flight, as they are optimized for axial air flow and cannot be inclined to adjust thrust vectors.

Innovation Solution

A thrust producing unit with rotors assemblies and shroudings that can be inclined, featuring upper and lower rotor assemblies with separate shroudings, allowing for improved aerodynamics and reduced drag by optimizing thrust vector alignment with air flow direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional ducts or shrouds are used to enclose rotors, then safety and noise abatement are improved, but drag increases and efficiency decreases during forward flight

Engineering Contradiction:
ImprovesafetyVSAvoiddrag
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The shrouding is made movable relative to the rotor assembly, allowing it to be positioned in different configurations. During forward flight, the shrouding can be moved to reduce drag, while during hover or vertical flight, it maintains its protective enclosure function. This dynamic adjustment resolves the contradiction between safety and drag reduction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The shrouding is divided into multiple segments or movable parts that can be independently adjusted. This segmentation allows specific portions of the shrouding to be repositioned to optimize aerodynamic performance during forward flight while maintaining safety enclosures when needed, thus reducing the overall drag without compromising safety.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If conventional ducts or shrouds are used to enclose rotors, then noise abatement is improved, but drag increases and power requirements increase during forward flight

Engineering Contradiction:
ImprovenoiseVSAvoidpower requirements
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The movable shrouding can be dynamically repositioned during forward flight to minimize its aerodynamic resistance, thereby reducing drag and the power required to maintain flight speed. When noise abatement is the priority (e.g., during hover or vertical operations), the shrouding returns to its enclosing position. This dynamic behavior resolves the contradiction between noise reduction and power consumption.

Inventive Principle:
Principle #15Dynamics

3Power

If rotors are enclosed in ducts or shrouds optimized for axial air flow, then thrust production in axial flow conditions is improved, but efficiency decreases in transversal air flow conditions

Engineering Contradiction:
Improvethrust productionVSAvoidefficiency
Core Design Contradiction:
PowerVSProductivity

Solution Approach 1:

The shrouding can be repositioned or reconfigured based on the flight condition. During axial flight operations, the shrouding maintains its optimized enclosure for maximum thrust production. During forward flight with transversal air flow, the shrouding is adjusted to reduce aerodynamic interference, thereby maintaining efficiency. This dynamic adaptability resolves the contradiction between thrust production and efficiency across different flight regimes.

Inventive Principle:
Principle #15Dynamics

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 solution enhances the efficiency and maneuverability of multirotor aircraft by reducing drag and power consumption during forward flight, while maintaining improved aerodynamics and safety features.

Implementation Method 1

at least two rotor assemblies (7d, 8d), each one defining an associated rotor plane (21, 22) and a rotor axis (12), both arranged coaxially

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 2

for producing thrust in a predetermined direction

Methodology Applied
Scientific EffectMomentum transfer: Conservation of Momentum

Data Source

PatentEP3354560B1A thrust producing unit with at least two rotor assemblies and a shrouding
Publication Date: 2022.06.08 AIRBUS HELICOPTERS DEUT GMBH
  • EP3354560B1 patent drawingFigure 1~2
  • EP3354560B1 patent drawingFigure 3~4
  • EP3354560B1 patent drawingFigure 5~6

AI summary

The invention is related to a thrust producing unit 3d for producing thrust in a predetermined direction 23, comprising a shrouding 6d and at least two rotor assemblies 7d, 8d, wherein the shrouding 6d defines an internal volume 20c, and wherein a first rotor assembly 7d of the at least two rotor assemblies 7d, 8d defines a first rotor axis and a second rotor assembly 8d of the at least two rotor assemblies 8d defines a second rotor axis, the first and second rotor axes 12d being one of: (i) coaxially arranged, and (ii) inclined by associated inclination angles 21a, 22a with respect to the predetermined direction 23, the associated inclination angles 21a, 22a being comprised in a range between -60° and +60°, and preferably amounting to 0°, and wherein the first rotor assembly 7d is arranged outside of the internal volume 20c of the shrouding 6d.