Segmented Deployable Propeller for UAV Stowage

Solution Overview

Problem

Existing collapsible propellers for UAVs lack flexibility and shape conformity due to a single mechanical hinge, resulting in incomplete stowage and aerodynamic inefficiencies, as well as a larger central yoke that reduces propeller disk area.

Innovation Solution

A deployable propeller design featuring multiple segments connected by flexible tensile materials, such as high-strength fibers or cloth, allowing blades to fold and conform to arbitrary surfaces for stowage, and interlock when deployed, with a telescoping faring to cover gaps and maintain tension, enabling better aerodynamic efficiency and compact storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single mechanical hinge is used to connect each blade to the central yoke, then the propeller structure is simple, but the blade cannot completely conform to the stowage surface and aerodynamic efficiency is reduced

Engineering Contradiction:

Improvehinge structureVSAvoidblade conformity to surface

Core Design Contradiction:

Device complexityVSShape

Solution Approach 1:

The blade is divided into multiple segments (first segment, second segment, third segment) that can independently rotate relative to each other about different hinges. This segmentation allows each segment to adapt to the curvature of the stowage surface while maintaining the overall blade shape during operation, resolving the contradiction between structural simplicity and shape conformity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The blade structure transitions from a static single-hinge design to a dynamic multi-segment design where segments can rotate independently. During stowage, segments rotate to conform to the surface curvature; during operation, they return to their operational positions. This dynamic adaptability resolves the contradiction between simplicity and conformity.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If a single mechanical hinge is used for each blade, then the hinging mechanism is simple, but the blade cannot follow arbitrary curvature and shape conformity is poor

Engineering Contradiction:

Improvehinging mechanismVSAvoidblade shape conformity

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The blade is divided into multiple segments (first segment, second segment, third segment) that can independently rotate relative to each other about different hinges. This segmentation allows each segment to adapt to the curvature of the stowage surface while maintaining the overall blade shape during operation, resolving the contradiction between structural simplicity and shape conformity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The blade structure transitions from a static single-hinge design to a dynamic multi-segment design where segments can rotate independently. During stowage, segments rotate to conform to the surface curvature; during operation, they return to their operational positions. This dynamic adaptability resolves the contradiction between simplicity and conformity.

Inventive Principle:

Principle #35Parameter changes

3Strength

If a large diameter central yoke is used in prior art folding propellers, then the hinging mechanism is robust, but the propeller disk area is reduced

Engineering Contradiction:

Improvehinging mechanism robustnessVSAvoidpropeller disk area

Core Design Contradiction:

StrengthVSArea of moving object

Solution Approach 1:

The blade segments nest together during stowage, with each segment rotating to align with the others, creating a compact configuration. The telescoping fairing also nests within the hub structure. This nesting reduces the effective yoke diameter and maximizes the propeller disk area during operation while maintaining structural robustness.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The blade segments rotate from a radial arrangement during operation to a more compact, multi-dimensional configuration during stowage. The segments fold in on themselves and align at different angles, effectively reducing the projected area of the yoke and maximizing the operational disk area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9937999B2Deployable propeller

Publication Date: 2018.04.10 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

A propeller which can be folded and stowed in compact form and then deployed for powered flight is disclosed. The deployable propeller has two or more blades, and each blade is composed of multiple segments which are disengaged when stowed and then interlock when deployed to form an efficient blade. The segmented deployable propeller retains all effective area to the spinner radius.