Offset X-rudder for Underwater Vehicle Sonar Stealth

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Solution Overview

Problem

Modern underwater vehicle rudder arrangements, such as X-rudder and cross rudder designs, are susceptible to detection by active sonar due to vertical surfaces or angled surfaces, which can lead to location by surface vehicles or submarines, compromising stealth capabilities without impairing maneuverability.

Innovation Solution

The rudder arrangement features offset groups of rudder blades in the longitudinal direction, with specific inclinations and positions to minimize reflective surfaces, using plastic foam materials and strategic placement near the stern or equator to reduce sonar reflection, and incorporating a flattened cross-section to avoid right angles with the hull.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional X-rudder or cross-rudder arrangements are used, then maneuverability is maintained, but vulnerability to active sonar detection increases due to vertical surfaces and 90° angled surfaces reflecting sound waves back to the transmitter

Engineering Contradiction:
Improvesonar detection vulnerabilityVSAvoidmaneuverability
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent applies dimensionality change by offsetting rudder blades not only vertically but also in the longitudinal direction (fore-aft dimension). This creates a three-dimensional staggered arrangement where rudder blades are positioned at different longitudinal locations, preventing the formation of planar reflective surfaces that would return sonar signals to the transmitter.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs asymmetry by arranging rudder blades in a non-uniform, staggered configuration rather than symmetric placement. The offset longitudinal positioning creates asymmetric surface orientations that disrupt regular sound wave reflection patterns, making it difficult for sonar to detect the vehicle through specular reflection.

Inventive Principle:
Principle #4Asymmetry

2Object-affected harmful factors

If rudder blades are offset in the longitudinal direction, then sonar detection vulnerability is reduced, but the complexity of the rudder arrangement increases

Engineering Contradiction:
Improvesonar detection vulnerabilityVSAvoidrudder arrangement complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the rudder assembly into multiple independent blade elements positioned at different longitudinal locations. Each rudder blade can be independently controlled and positioned, allowing the system to achieve sonar evasion through staggered arrangement while maintaining modular construction that simplifies manufacturing and maintenance.

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

This configuration significantly reduces susceptibility to active sonar detection while maintaining maneuverability by avoiding direct sound wave reflections and minimizing the target dimension, enhancing the stealth capabilities of underwater vehicles.

Implementation Method 1

This is due to the fact that detection by a surface vessel or submarine with active sonar is usually at an angle of less than 10° to the horizontal due to the distance... These therefore do not form surfaces arranged at an angle of approximately 90° to each other, thereby preventing a reflection of a sound wave from an active sonar back to the transmitter.

Methodology Applied
Scientific EffectSound wave reflection: Reflection

Data Source

PatentEP3560815B1Rudder arrangement
Publication Date: 2020.04.29 THYSSENKRUPP AG
  • EP3560815B1 patent drawingFigure 1~2

AI summary

The present invention relates to an underwater vehicle with an X-rudder, wherein the rudder blades are arranged offset in the longitudinal direction of the underwater vehicle.