Pivot Blocking Door for Tiltrotor Pylon Signature Reduction

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Solution Overview

Problem

Tiltrotor aircraft face issues with exposed proprotor components that increase infrared and radar signatures and are vulnerable to damage from external sources, affecting aerodynamic performance during helicopter and conversion modes of operation.

Innovation Solution

A blocking door is introduced, pivotally disposed on the fixed nacelle, which rotates to block exposed proprotor components when the proprotor pylon is in non-horizontal positions, using a linkage or actuator to position itself in front of the proprotor pylon, made from materials like ceramic, composite, or metallic materials to reduce signatures and protect against damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the pylon fairing is designed with openings to allow rotation and access, then the proprotor pylon can be rotated between modes and components can be accessed, but exposed proprotor components increase infrared and radar signatures and are vulnerable to damage

Engineering Contradiction:

Improveproprotor pylon rotation between modesVSAvoidinfrared and radar signatures, vulnerability to damage

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The blocking door is designed to be movable rather than fixed, allowing it to pivot between a stowed position (enabling proprotor pylon rotation and component access) and a blocking position (covering exposed components to reduce signatures and protect from damage). This dynamic configuration resolves the contradiction by adapting the door's position based on operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The blocking door is segmented from the main pylon fairing structure, allowing independent movement and positioning. This segmentation enables the door to be independently controlled to block or expose specific areas as needed, resolving the contradiction between accessibility and protection.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If the blocking door is made from heavy protective materials, then protection against ballistic and environmental strikes is improved, but the weight of the moving component increases

Engineering Contradiction:

Improveprotection against ballistic and environmental strikesVSAvoidweight of blocking door

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The blocking door is constructed from composite materials that provide high strength and protective properties against ballistic and environmental strikes while maintaining relatively low weight. This resolves the contradiction by achieving protection without the excessive weight that would result from traditional heavy protective materials.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10994852B2Door for a tiltrotor proprotor pylon

Publication Date: 2021.05.04 BELL HELICOPTER TEXTRON INC

AI summary

An embodiment of the present invention provides a blocking door that is pivotally disposed on a fixed nacelle of a tiltrotor aircraft for pivoting between a stowed position when a proprotor pylon is in the substantially horizontal position and a protective blocking position in front of the proprotor pylon when the proprotor pylon is positioned in the non-horizontal position. In other aspects, there is provided a blocking door and a method of reducing infrared and/or radar signatures of rotorcraft with a rotatable proprotor.