Common Door Sealing for Dispenser Aerodynamic Noise

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Solution Overview

Problem

Existing counter-measure dispensers on military aircraft face issues with interfering noise and vibrations caused by the opening of compartments during payload launch, which can lead to vehicle detection by enemy missiles and structural damage, and require complex mechanisms with multiple movable parts.

Innovation Solution

A dispenser unit with a common door mechanism, such as a flexible shutter or folding curtain, driven by a single motor or pneumatic system, that seals compartments after payload launch, minimizing noise and vibrations by using a spoiler to reduce wind impact and allowing for simple maintenance and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If individual piston arrangements are used to seal each compartment after payload launch, then aerodynamic loads and vibration effects are eliminated, but device complexity increases due to multiple movable parts

Engineering Contradiction:
Improveaerodynamic loads and vibration effectsVSAvoidnumber of movable parts
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the sealing function for multiple compartments into a single common door mechanism. Instead of having separate piston arrangements in each compartment, one door means is shared across multiple compartments and sequentially seals them after payload deployment. This reduces the number of movable parts from multiple individual pistons to a single door assembly, thereby reducing device complexity while still eliminating aerodynamic loads and vibration effects.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common door mechanism serves multiple functions: it acts as a seal for multiple different compartments, replaces multiple individual piston arrangements, and provides a unified aerodynamic surface for the entire dispenser unit. This multi-functional design eliminates the need for separate sealing mechanisms in each compartment, reducing overall system complexity while maintaining the benefits of sealed compartments.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate door mechanisms with individual driving means are used for each compartment, then each compartment can be sealed independently, but device complexity and space requirements increase

Engineering Contradiction:
Improveindependent compartment sealingVSAvoidnumber of driving means
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple individual door mechanisms into a single common door means that serves multiple compartments. Instead of having separate driving means for each compartment, one driving mechanism controls the single door to seal multiple compartments in sequence. This merging approach reduces device complexity and space requirements while maintaining reliable sealing of each compartment through the shared door mechanism.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If compartments remain open after payload launch, then no additional sealing mechanisms are needed, but interfering noise and vibrations occur causing vehicle detection and structural damage

Engineering Contradiction:
Improvesealing mechanismVSAvoidinterfering noise and vibrations
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the aerodynamic surface of the dispenser unit by introducing a common door means that can seal individual compartments after payload deployment. This segmentation creates a smooth, continuous surface across previously open compartment openings, preventing turbulent air flow, reducing interfering noise and vibrations, and eliminating the harmful effects of open compartments without requiring complete redesign of the dispenser structure.

Inventive Principle:
Principle #1Segmentation

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

The solution effectively reduces noise and vibrations, enhancing the reliability and stealth of the aircraft by using a single door mechanism to seal compartments, thereby preventing detection and structural damage, while maintaining a compact and cost-effective design.

Implementation Method 1

arrange a spoiler in front of the opening of the compartment for creating a low dynamic pressure across the opening thereby reducing the interfering noise and vibrations

Methodology Applied
Scientific EffectDynamic pressure: Bernoulli Effect

Implementation Method 2

Each compartment has a piston arrangement for sealing the opening, thereby eliminating the aerodynamic loads and vibration effects which are present whenever an open compartment otherwise is subjected to supersonic velocity air streams

Methodology Applied
Scientific EffectAerodynamic loading: Drag

Data Source

PatentEP2421754B1Dispenser Unit with closable counter-measure compartments
Publication Date: 2016.10.19 SAAB AB
  • EP2421754B1 patent drawingFigure 1a~2
  • EP2421754B1 patent drawingFigure 3~6

AI summary

The present invention relates to a dispenser unit (1) comprising a plurality of compartments (7), each of which is adapted for storing and launching a payload (3, 4, 51) and comprises an opening (9) through which the payload (3, 4, 51) is launched by means of a control unit (13), a door means is associated with the opening (9) and is driven by a driving means (19, 37). The dispenser unit (1) comprises one common door means (17, 41) being arranged in such way that it is drivable to cover the openings (9) of the compartments (7) from which the payloads (3, 4, 51) have been launched.