Grenade Flow Cross-Section Reduction Device for Recoilless Launchers

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Solution Overview

Problem

Existing barrel-loading grenade launchers achieve recoilless firing but suffer from a weak propulsion effect due to rapid escape of propellant gases through open-ended tubes, resulting in insufficient thrust on the grenade.

Innovation Solution

A flow cross-section reduction device connected to the grenade main body via a firing-resistant connection, which narrows the exit to prevent gas pressure escape, combined with a cylindrical grenade base and sealing means to maximize charge volume and optimize guidance, and a wired data link to ensure communication with a fire control computer while minimizing exposure to hot gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the rear opening of the launch tube is narrowed to increase propulsive effect, then the propulsion effect on the grenade is improved, but axial rearwardly directed forces are introduced into the launch device

Engineering Contradiction:
Improvepropulsion effectVSAvoidaxial forces
Core Design Contradiction:
PowerVSForce

Solution Approach 1:

The flow cross-section reduction device is segmented from the launch tube structure, connected via a connection device at a distance from the grenade main body. This segmentation allows the flow cross-section to be reduced for increased propulsion while the connection device isolates the axial forces from the launch tube, preventing force transmission to the launch device.

Inventive Principle:
Principle #1Segmentation

2Power

If a flow cross-section reduction device is permanently connected to the launch tube to prevent gas escape, then propulsive effect is improved, but axial forces are transmitted to the barrel

Engineering Contradiction:
Improvepropulsion effectVSAvoidaxial forces
Core Design Contradiction:
PowerVSForce

Solution Approach 1:

The connection device acts as an intermediary element between the flow cross-section reduction device and the grenade main body. It provides a firing-resistant connection that secures the reduction device in position while preventing the transmission of axial forces to the launch tube, thus mediating between the need for gas containment and force isolation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the launch tube is open on both sides for simple recoilless firing, then device complexity is reduced, but propellant gases escape rapidly reducing propulsion effect

Engineering Contradiction:
Improvegrenade launcher designVSAvoidpropulsion effect
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The flow cross-section reduction device is designed to be dynamically positioned within the launch tube during firing, with the connection device allowing it to be secured in the firing position while maintaining the overall simplicity of the open-tube design. This dynamic approach preserves the simplicity of the launch tube structure while adding flow control capability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2339285B8Grenade and grenade launching device
Publication Date: 2017.05.31 DIEHL DEFENCE GMBH & CO KG

AI summary

The grenade (1) has a grenade base body (10) surrounding an explosive charge. A flow cross-section reduction device (12) i.e. ring control unit, reduces flow cross-section of a firing tube and arranged with respect to the base body in opposite direction to a firing direction. The reduction device is connected with the base body by a connecting device (13). The body has a cylindrical shape and has outer diameter corresponding to inner diameter of the firing tube. The body has a sealing unit (14) for sealing gap between shell surface of the body and an inner surface of the tube.