Aircraft Pitch Horn Assembly with Moveable Arm

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Solution Overview

Problem

Conventional rotor assemblies have fixed pitch horns that cannot be adjusted during rotation, leading to inadequate pitch-flap coupling, increased rotor blade stiffness and weight, and limited versatility across different aircraft and rotor assemblies.

Innovation Solution

A pitch horn assembly with a moveable arm and extendable member that adjusts the pitch horn radius and position relative to the rotor blade, allowing for improved pitch-flap coupling and adaptability across various aircraft and rotor assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional fixed pitch horns are used, then the structure is simple, but pitch-flap coupling is inadequate and rotor blade weight increases

Engineering Contradiction:

Improvepitch horn structureVSAvoidrotor blade weight

Core Design Contradiction:

Device complexityVSWeight of moving object

Solution Approach 1:

The pitch horn assembly incorporates a moveable arm that can dynamically adjust its position relative to the rotor blade during rotation. The extendable member allows the pitch horn radius to be varied, transforming the static fixed pitch horn into a dynamic adjustable structure that optimizes pitch-flap coupling without requiring increased blade stiffness and weight

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameter of the pitch horn radius by extending or retracting the extendable member. This parameter change allows optimization of pitch-flap coupling characteristics during rotor rotation, achieving the desired performance without increasing rotor blade weight through stiffness enhancements

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If conventional fixed pitch horns are used, then the structure is simple, but pitch-flap coupling performance deteriorates

Engineering Contradiction:

Improvepitch horn structureVSAvoidpitch-flap coupling

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The moveable arm with extendable member enables dynamic adjustment of pitch horn position during rotor rotation, allowing the system to adapt to varying operational conditions and maintain optimal pitch-flap coupling performance across different flight regimes, thereby improving reliability

Inventive Principle:

Principle #15Dynamics

3Reliability

If rotor blade stiffness is increased to compensate for inadequate pitch-flap coupling, then pitch-flap coupling improves, but rotor blade weight increases

Engineering Contradiction:

Improvepitch-flap couplingVSAvoidrotor blade weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

Instead of increasing blade stiffness, the invention dynamically adjusts the pitch horn radius during rotation to optimize pitch-flap coupling. This approach achieves the desired coupling performance through geometric adjustment rather than material property changes, avoiding the weight penalty of stiffer blades

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the pitch horn radius parameter during operation to achieve optimal pitch-flap coupling, replacing the need for increased blade stiffness with a geometric parameter adjustment that does not increase blade weight

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If conventional fixed pitch horns are used, then manufacturing is straightforward, but adaptability across different aircraft deteriorates

Engineering Contradiction:

Improvepitch horn manufacturingVSAvoidadaptability across aircraft

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The pitch horn assembly with moveable arm and extendable member is designed as a universal component that can be adapted to multiple aircraft types and rotor assembly configurations. The adjustability features allow a single design to serve multiple applications, improving versatility without significantly complicating manufacturing

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The dynamic adjustability of the pitch horn radius allows a single standardized assembly to be configured for different aircraft and rotor assemblies, replacing the need for custom-tailored fixed pitch horns for each application and thereby improving adaptability

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10343772B2Pitch horn assembly

Publication Date: 2019.07.09 BELL HELICOPTER TEXTRON INC

AI summary

A pitch horn assembly for an aircraft including a blade attachment member having a first end, a second end configured to be coupled to a rotor blade; and a blade attachment axis extending between the first end and the second end of the blade attachment member; a moveable arm configured to be coupled to the blade attachment member at a pitch horn axis, the moveable arm having a first end configured to be coupled to a pitch link; a second end; and a moveable arm axis extending between the first end and the second end of the moveable arm; an extendable member configured to be coupled to the blade attachment member and the moveable arm of the pitch horn, wherein the extendable member moves the moveable arm about the pitch horn axis. An embodiment provides a method of adjusting a pitch-flap coupling in an aircraft.