Hybrid Aircraft Firewall Assemblies for Fire Zone Separation

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Solution Overview

Problem

Conventional firewall assemblies are inadequate for hybrid electric aircraft powerplants, as they fail to provide sufficient redundancy and independence between electric motor and heat engine fire zones, posing a risk of fire propagation and compromising safety.

Innovation Solution

A hybrid electric powerplant design featuring a firewall that separates electric motor and heat engine fire zones, with a nacelle housing both components and a fire extinguisher system for independent extinguishing of each zone, utilizing a metallic or composite baffle to contain the electric motor and providing ventilation pathways for each zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional firewall assemblies are used in hybrid electric powerplants, then the structure is simple and easy to manufacture, but the fire zones are not sufficiently separated, allowing fire propagation between electric motor and heat engine

Engineering Contradiction:

Improvefire zone separationVSAvoidfirewall assembly structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The firewall assembly is segmented into multiple independent components: a forward firewall, an aft firewall, and lateral firewalls that together create separate fire zones for the electric motor and heat engine. This segmentation ensures that fire cannot propagate between the two power sources while maintaining manageable complexity through modular construction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The firewall structure employs nested containment where firewalls are positioned within the nacelle housing, creating nested fire zones. The electric motor fire zone and heat engine fire zone are nested within the overall nacelle structure, providing multiple layers of fire containment and separation.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If a firewall separates electric motor and heat engine fire zones, then fire propagation is prevented and safety is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvefire propagation riskVSAvoidfirewall assembly manufacturing

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

Different sections of the firewall assembly have different properties optimized for their specific functions. The forward and aft firewalls have different configurations than the lateral firewalls, with each section designed to address specific fire propagation risks in its location while using standardized materials and construction methods.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The firewall assembly utilizes composite construction methods, combining different materials and structural approaches in various sections. This allows each firewall component to be manufactured using the most suitable methods for its specific requirements, improving ease of manufacture while maintaining effective fire separation.

Inventive Principle:

Principle #40Composite materials

3Reliability

If independent fire zones are created for electric motor and heat engine, then redundancy and safety are improved, but the nacelle space requirements and device complexity increase

Engineering Contradiction:

Improvepower lane redundancyVSAvoidnacelle volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The fire zones are separated not only longitudinally (forward-aft) but also laterally, utilizing three-dimensional space within the nacelle. This multi-dimensional arrangement allows independent fire zones for the electric motor and heat engine while efficiently packing the available nacelle volume, reducing the overall space required compared to simple linear separation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 design ensures independent protection of the electric motor and heat engine against fires, allowing for safe operation even in the event of a failure in one power lane, increasing aircraft safety and range during emergencies.

Implementation Method 1

an electric motor configured to convert electrical energy into kinetic energy to turn a propulsor

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a heat engine configured to convert a fuel into kinetic energy to turn the propulsor

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11603800B2Firewall assemblies for hybrid electric aircraft powerplants

Publication Date: 2023.03.14 ROHR INC

AI summary

A hybrid electric powerplant can include an electric motor configured to convert electrical energy into kinetic energy to turn a propulsor, and a heat engine configured to convert a fuel into kinetic energy to turn the propulsor. The powerplant can include a firewall disposed around at least one of the electric motor or the heat engine to create an electric motor fire zone and a heat engine fire zone separate from the electric motor fire zone such that the electric motor is protected against a heat engine fire, and vice versa.