Foldable Lift Rotor Blade Hinge for Road-Width Conversion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Convertible vehicles with lift rotors face challenges in reducing vehicle width for road traffic conditions while maintaining aerodynamic efficiency and compliance with road regulations, as existing solutions like blade removal or longitudinal alignment are impractical or inefficient.

Innovation Solution

The rotor blades are designed with a hinge structure having two parallel hinge axes, allowing them to be folded vertically and laid parallel to each other, with a seamless aerodynamic surface, and a folding control mechanism ensures correct folding order without user intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If rotor blades are designed to be easily removed and replaced, then maintenance and storage become simpler, but the connection reliability between rotor blade and rotor hub may be compromised

Engineering Contradiction:
Improveease of rotor blade replacementVSAvoidconnection reliability
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The rotor blade is divided into a blade root portion and a blade body portion, with the blade root further segmented into an insertion portion and a fastening portion. This segmentation allows the blade to be easily disconnected and reconnected while maintaining connection reliability through the dedicated fastening structure with multiple fastening elements distributed along the insertion portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rotor blade pre-compression member is pre-loaded to apply a compression force to the fastening portion before operational loads are applied. This preliminary action ensures that the fastening elements are already engaged and secured to the rotor hub, preventing loosening during operation and maintaining connection reliability while allowing easy replacement when needed.

Inventive Principle:
Principle #10Preliminary action

2Weight of moving object

If rotor blades are made lighter to reduce overall rotor weight, then energy consumption decreases, but the structural strength and durability may be reduced

Engineering Contradiction:
Improverotor blade weightVSAvoidstructural strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The rotor blade employs a composite structure where the blade root portion (particularly the insertion portion) is made from a material with different properties than the blade body portion. This allows optimization of each section: the blade body can be lightweight while the blade root provides the necessary strength and stiffness for connection to the rotor hub, thus reducing overall weight without compromising structural integrity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different portions of the rotor blade are designed with different material properties and structural characteristics. The blade root portion has enhanced strength and stiffness to handle connection loads, while the blade body portion is optimized for lightweight performance. This local differentiation allows the blade to be lighter overall while maintaining sufficient structural strength where it is most needed.

Inventive Principle:
Principle #3Local quality

3Reliability

If multiple fastening elements are used to secure rotor blades, then connection reliability improves, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidfastening structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple fastening elements are integrated into a unified fastening structure where the pre-compression member applies a single compression force that is distributed to multiple fastening elements along the insertion portion. This merging approach maintains connection reliability through multiple engagement points while simplifying the overall assembly process compared to using multiple independent fastening mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

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 enables compact vehicle configuration for road use, maintaining aerodynamic efficiency and compliance with road regulations, while allowing easy conversion to flying mode by a single person.

Implementation Method 1

the rotor blade pre-compression member to which the compression force is applied in order to fasten the rotor blade to the rotor hub

Methodology Applied
Scientific EffectCompression force: Compression

Implementation Method 2

a first reinforcement piece extending in a direction intersecting with the longitudinal axis of the rotor blade and a second reinforcement piece extending in a direction coinciding with the longitudinal axis of the rotor blade are disposed in the blade root portion

Methodology Applied
Scientific EffectBending stiffness:

Data Source

PatentEP3941827B1Rotor blades of a lift rotor
Publication Date: 2026.05.06 PAL V IP BV
  • EP3941827B1 patent drawingFigure 1A~1B
  • EP3941827B1 patent drawingFigure 2~4
  • EP3941827B1 patent drawingFigure 5

AI summary

A foldable rotor blade (152, 153) comprises a hinge element (173; 240) defining two hinge axes arranged in parallel, and two blade segments (171, 172) each coupled to the hinge element (173; 240) for hinging with respect to a respective one of said hinge axes. The rotor blade has an extended condition in which the blade segments are substantially aligned with each other; the rotor blade has a folded condition in which each blade segment is hinged with respect to the hinge element so that the blade segments are substantially parallel to each other. The blade has a cord (14) and said hinge axes are substantially parallel to the chord. The blade segments have upper surfaces which in the folded condition are facing each other, and which in the extended condition are flush with each other and the intermediate hinge element.