Hinged Rotor Blade Passive Variable Pitch Mechanism

Solution Overview

Problem

Existing variable pitch propellers require complex mechanical and hydraulic mechanisms, which are heavy, costly to maintain, and impractical for applications where weight is prohibitive, such as electric motor-driven rotors.

Innovation Solution

A hinged rotor blade design that passively changes pitch in response to changes in orientation and forces, using a hinge mechanism oriented at an acute angle to allow the blade to rotate inward and change pitch without the need for mechanical or hydraulic systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mechanical linkage and hydraulics are used to control variable pitch propeller, then pitch control capability is improved, but device complexity and weight increase

Engineering Contradiction:

Improvepitch control capabilityVSAvoidmechanical linkage and hydraulic mechanisms

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The blade automatically adjusts its pitch angle through aerodynamic forces acting on the hinge mechanism, eliminating the need for external mechanical linkages or hydraulic systems. The blade serves its own pitch control function by responding to changes in flight conditions through the hinge's passive mechanical response to aerodynamic loads.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical linkages and hydraulic systems with a simple hinge mechanism that uses aerodynamic forces to control blade pitch. This substitution eliminates the need for motors, linkages, and hydraulic fluid systems while maintaining pitch variability capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If mechanical linkage and hydraulics are used to control variable pitch propeller, then pitch control capability is improved, but weight increases

Engineering Contradiction:

Improvepitch control capabilityVSAvoidpropeller weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The blade automatically adjusts its pitch angle through aerodynamic forces acting on the hinge mechanism, eliminating the need for external mechanical linkages or hydraulic systems. The blade serves its own pitch control function by responding to changes in flight conditions through the hinge's passive mechanical response to aerodynamic loads.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical linkages and hydraulic systems with a simple hinge mechanism that uses aerodynamic forces to control blade pitch. This substitution eliminates the need for motors, linkages, and hydraulic fluid systems while maintaining pitch variability capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If mechanical linkage and hydraulics are used to control variable pitch propeller, then pitch control capability is improved, but maintenance requirements increase

Engineering Contradiction:

Improvepitch control capabilityVSAvoidmaintenance requirements

Core Design Contradiction:

Adaptability or versatilityVSEase of repair

Solution Approach 1:

The blade automatically adjusts its pitch angle through aerodynamic forces acting on the hinge mechanism, eliminating the need for external mechanical linkages or hydraulic systems. The blade serves its own pitch control function by responding to changes in flight conditions through the hinge's passive mechanical response to aerodynamic loads.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical linkages and hydraulic systems with a simple hinge mechanism that uses aerodynamic forces to control blade pitch. This substitution eliminates the need for motors, linkages, and hydraulic fluid systems while maintaining pitch variability capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables efficient and lightweight variable pitch control, reducing maintenance needs and weight, while optimizing thrust and lift generation across different flight modes without the complexity of traditional control systems.

Implementation Method 1

The blade(s) is/are connected to the hub or nose section via a hinge mechanism, such as a pin hinge, oriented at an acute or other angle to a tangent to the hub or nose section

Methodology Applied

Scientific EffectHinge mechanism: Hinge

Data Source

PatentUS12172746B2Hinged rotor blade to provide passive variable pitch

Publication Date: 2024.12.24 KITTY HAWK CORP

AI summary

A propeller comprising a hub, a blade, and a hinge is disclosed. In various embodiments, a blade includes a neck portion angled away from a plane of rotation of the hub, wherein the blade has a longitudinal axis extending through the blade and running from a tip of the blade to an end of the neck portion, and a dihedral angle of the blade is an angle of the blade relative to the plane of rotation of the hub. The hinge includes a pivotal link, and connects the blade to the hub, wherein the hinge has an axis of rotation that is offset from a line perpendicular to the longitudinal axis of the blade, and responds to forces acting on the blade to vary a pitch of the blade including causing the blade to be at a lower pitch and higher dihedral angle in a first mode.