Folding Propeller Linkage for Air Mobility Drag Reduction

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Solution Overview

Problem

Current foldable propeller systems for air mobility lack a reliable and stable mechanism to fold and deploy blades independently during flight, leading to energy loss due to drag caused by unused propellers during cruising.

Innovation Solution

A foldable propeller design featuring a shaft with a hub, rotating blades, a moving portion, and a link assembly that allows blades to be folded and unfolded by sliding the moving portion along the shaft, enabling simultaneous folding and pitch control, reducing drag and improving energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If propellers are kept in deployed state for VTOL operations, then lifting capability is ensured, but drag increases during cruising causing energy loss

Engineering Contradiction:

Improveenergy lossVSAvoidlifting capability

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The propeller system transitions from static deployed state to dynamic reconfigurable state by enabling blade folding and pitch angle adjustment during flight, allowing the propeller to adapt between VTOL and cruising modes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The propeller blade is divided into multiple segments (root section, intermediate section, tip section) that can independently adjust pitch angles, enabling selective pitch control for different blade portions to optimize performance during mode transitions

Inventive Principle:

Principle #1Segmentation

2Productivity

If propellers are folded to reduce drag, then energy efficiency improves, but folding reliability and stability are compromised

Engineering Contradiction:

Improveenergy efficiencyVSAvoidfolding reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The folding mechanism incorporates pre-designed stoppers, guides, and damping elements that prevent over-folding and absorb impact forces during blade folding/unfolding, ensuring reliable and stable operation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

Linkages and intermediate mechanical structures are introduced between the blade and hub to mediate the folding motion, providing controlled movement paths and ensuring synchronized folding of multiple blades

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If simultaneous folding and pitch control is implemented, then device complexity increases, but operational versatility is enhanced

Engineering Contradiction:

Improveoperational versatilityVSAvoidmechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The folding mechanism and pitch control system are merged into a single integrated structure where the same linkages and mechanical elements perform both folding and pitch angle adjustment functions, reducing overall system complexity

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11745854B2Folding propeller for air mobility

Publication Date: 2023.09.05 HYUNDAI MOTOR CO LTD

AI summary

A foldable propeller for air mobility includes a link assembly including a plurality of links facilitating blades to be rotated around a hub as a moving portion vertically slides such that the blades are folded to each other or unfolded from each other.