Movable Propeller Guard for Aerial Vehicle Drag Reduction

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Solution Overview

Problem

Conventional aerial vehicles using propellers for lift and flight control face limitations in hover-type flight modes, including high power consumption, cross-flow drag, pitchback instability, and pendulum instabilities due to heavy training cross-arms, which compromise maneuverability and stability.

Innovation Solution

The design incorporates a spherical body with at least three aerodynamic propulsors positioned to provide lifting thrust, pitch, yaw, and roll control, supported by a structural arch that doubles as a propulsor guard and movable members to mitigate cross-flow drag and enhance stability, while also protecting the propulsors from damage and improving visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional propeller guards are used to protect propellers, then propeller damage is prevented, but cross-flow drag and pitchback instability increase

Engineering Contradiction:

Improvepropeller protectionVSAvoidcross-flow drag

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs flexible propeller guard members that can bend and deform under aerodynamic loads. These flexible guards reduce cross-flow drag by allowing the structure to conform to airflow patterns while still providing protective coverage for the propellers, resolving the contradiction between protection and drag reduction.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The propeller guard system is designed with dynamic characteristics, allowing the guard members to move and adjust their position in response to flight conditions. This dynamic behavior reduces pitchback instability by enabling the guards to adapt to changing aerodynamic forces during hover and flight operations.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If heavy training cross-arms are added to landing gear for flight training, then flight learning is enabled, but pendulum instabilities and maneuverability are compromised

Engineering Contradiction:

Improveflight training capabilityVSAvoidpendulum instability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The training cross-arms are segmented into multiple lighter components distributed across the landing gear structure. This segmentation reduces the concentrated weight that causes pendulum instability while maintaining the training functionality through distributed support structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The training cross-arms are constructed using composite materials that provide high strength-to-weight ratios. This allows the training structures to be sufficiently strong for flight training purposes while minimizing the weight that would otherwise exacerbate pendulum instabilities and reduce maneuverability.

Inventive Principle:

Principle #40Composite materials

3Ease of operation

If conventional training cross-arms are positioned close to ground for training, then flight learning is facilitated, but propeller damage risk increases from downward strikes

Engineering Contradiction:

Improveflight training accessibilityVSAvoidpropeller strike risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The training cross-arms are nested within or integrated with the propeller guard structure, creating a layered protective system. This nesting arrangement ensures that the training structures are positioned close to the ground for training purposes while being protected by the outer propeller guard members that prevent direct strikes to the propellers.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Ease of operation

If feather arrangements are used for locomotion, then flight control is achieved, but power consumption increases significantly

Engineering Contradiction:

Improveflight control capabilityVSAvoidpower consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent extracts the essential flight control function from the complex feather arrangement system and implements it through simpler, more efficient aerodynamic surfaces. By taking out only the necessary control functionality and eliminating the power-intensive feather mechanism, the system achieves flight control with significantly reduced power consumption.

Inventive Principle:

Principle #2Taking out (Extraction)

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

This configuration allows for more stable and maneuverable hover and vertical climb operations with reduced drag, increased safety by protecting the aircraft and bystanders from propeller damage, and a lower weight-to-thrust ratio, enhancing the strength-to-weight ratio of the aerial vehicle.

Implementation Method 1

at least three aerodynamic propulsors positioned relative to the longitudinal axis to provide lifting thrust, pitch, yaw and roll control

Methodology Applied

Scientific EffectAerodynamic lift: Aerofoil

Data Source

PatentUS10561956B2Moveable member bearing aerial vehicles and methods of use

Publication Date: 2020.02.18 UNIVERSITY OF KANSAS

AI summary

An aerial vehicle includes a body having a longitudinal axis, a plurality of movable members emanating connected to the body, at least one motor, and at least three aerodynamic propulsors driven by the at least one motor. The movable members are connected to the body and extend away from the body.