Helicopter Engine Fire Nozzle Design for Water and FOD Drainage

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Solution Overview

Problem

Existing fire extinguishing systems in aircraft engine compartments are prone to accumulation of water, rain, humidity, and foreign object debris (FOD) due to upward-facing nozzles, leading to corrosion, blockages, and reduced system efficacy.

Innovation Solution

Reorienting fire extinguishing nozzles to face downward or incorporating features like chamfered openings, inverted traps, and spring-loaded covers to prevent liquid ingress and FOD, ensuring effective drainage and protection against corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nozzles are oriented upward-facing to discharge fire extinguishing agent, then the agent can be effectively distributed into the engine compartment, but water, rain, humidity, and FOD accumulate in the nozzle and agent tube, causing corrosion and blockages

Engineering Contradiction:

Improvefire extinguishing system efficacyVSAvoidliquid accumulation and corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The nozzle is inverted to face downward instead of upward, so that water, rain, humidity, and FOD drain away from the nozzle and agent tube rather than accumulating in them. This inversion maintains effective agent distribution while eliminating the harmful accumulation problem.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The downward orientation converts the harmful effect of gravity on liquids into a beneficial drainage mechanism, allowing water and FOD to naturally drain away from the system components rather than accumulating and causing corrosion.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If nozzles are oriented downward-facing to prevent liquid accumulation, then drainage is improved, but the fire extinguishing agent distribution effectiveness may be reduced

Engineering Contradiction:

Improveliquid and FOD drainageVSAvoidfire extinguishing agent distribution

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The nozzle opening is designed with a specific local geometry (chamfered opening) that directs the fire extinguishing agent upward and outward while allowing water and FOD to drain downward. This local quality differentiation enables simultaneous achievement of both drainage and effective agent distribution.

Inventive Principle:

Principle #3Local quality

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

Prevents accumulation of water and FOD, reducing corrosion and blockages, thereby maintaining the integrity and performance of the fire extinguishing system.

Implementation Method 1

The hinged cover may be held in a closed position by a spring. The spring may be configured to assert a force that is overcome by pressure generated by a fire extinguishing agent released from the fire bottle.

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

The membrane may be configured to rupture or release when exposed to pressure generated by a fire extinguishing agent released from the fire bottle.

Methodology Applied

Scientific EffectPressure-induced rupture: Pressure Increase

Data Source

PatentUS12357858B2Fire extinguishing discharge nozzle for helicopter engine compartment

Publication Date: 2025.07.15 TEXTRON INNOVATIONS INC

AI summary

Embodiments are directed to a rotorcraft comprising an airframe having an engine compartment, an engine disposed within the engine compartment, at least one fire bottle configured to hold a fire extinguishing agent, at least one agent tube coupled to the fire bottle and configured to carry the fire extinguishing agent to the engine compartment, and a nozzle on the at least one agent tube, the nozzle positioned below the engine and oriented in a upward-facing direction. The nozzle has at least one opening that is closed by a spring-loaded valve.