Projectile Launcher with Segmented Propellant Compartment

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Solution Overview

Problem

Existing methods for launching projectiles from shoulder-fired weapons face challenges in achieving high projectile velocity while minimizing acoustic pressure and stress on the barrel, often requiring longer barrels and heavier weapons.

Innovation Solution

A method involving a projectile with a rocket motor at its rear end and a countermass at the barrel's rear, featuring a high-pressure chamber formed by two propellant compartments, where combustion gases accelerate the projectile and countermass, and a nozzle maintains high pressure to continue accelerating the projectile after the countermass exits the barrel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If rocket motor thrust is used to launch the projectile, then acoustic pressure is reduced and acceleration stress is lowered, but projectile velocity is reduced

Engineering Contradiction:
Improveacoustic pressureVSAvoidprojectile velocity
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The launching system is segmented into two distinct propellant compartments: a first compartment (rocket motor) that operates at lower pressure to reduce acoustic effects, and a second compartment that operates at higher pressure to provide additional acceleration. This segmentation allows each compartment to optimize its function independently, resolving the contradiction between reducing acoustic pressure and maintaining high projectile velocity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges two different propellant charging methods (rocket motor thrust and high-pressure gas acceleration) into a single integrated system. The first and second compartments work together in sequence, combining the benefits of low-acoustic-pressure rocket propulsion with the high-velocity acceleration of pressurized gas, thereby achieving both reduced acoustic pressure and high projectile velocity.

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If Davis-Gun principle with countermass is used, then acoustic pressure is reduced, but barrel length and weapon weight must be increased

Engineering Contradiction:
Improveacoustic pressureVSAvoidbarrel length
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The propellant system is segmented into two compartments with different pressure characteristics. The second compartment uses a propellant charge optimized for shorter acceleration distance, eliminating the need for long barrels while still achieving low acoustic pressure through the first compartment's rocket motor design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the pressure parameters by using two different propellant charges with different operating pressures. The second compartment uses a high-pressure propellant (20-60 MPa) that provides rapid acceleration over a shorter distance, reducing the required barrel length while maintaining low acoustic pressure through the first compartment's design.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If Davis-Gun principle with countermass is used, then acoustic pressure is reduced, but weapon weight must be increased

Engineering Contradiction:
Improveacoustic pressureVSAvoidweapon weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The invention extracts and eliminates the heavy countermass component from the Davis-Gun principle by using a rocket motor in the first compartment that provides recoil compensation through controlled exhaust. This allows the system to achieve low acoustic pressure without requiring the heavy countermass, thereby reducing overall weapon weight.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical countermass system is replaced with a rocket motor system that provides equivalent recoil management through thrust vectoring and controlled exhaust. This substitution eliminates the need for heavy mechanical counterweights while maintaining acoustic pressure reduction, significantly reducing weapon weight.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Weight of stationary object

If recoilless back blast launcher is used, then weapon weight is reduced, but acoustic pressure and acceleration stress are increased

Engineering Contradiction:
Improveweapon weightVSAvoidacoustic pressure
Core Design Contradiction:
Weight of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The launcher is segmented into two propellant compartments with different functions: the first compartment (rocket motor) is designed to reduce acoustic pressure through controlled exhaust, while the second compartment provides the main propelling force. This segmentation allows the system to maintain low weapon weight while simultaneously reducing acoustic pressure, overcoming the limitations of conventional recoilless launchers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges rocket motor propulsion with high-pressure gas acceleration in a single integrated system. The rocket motor component reduces acoustic pressure and stress, while the second propellant compartment maintains high projectile velocity, achieving low acoustic pressure without sacrificing performance or requiring heavy weapon construction.

Inventive Principle:
Principle #5Merging (Combining)

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 approach enhances projectile acceleration, maintains velocity for a longer period, reduces stress on the barrel, and utilizes the barrel length more effectively, improving internal ballistics and reducing recoil forces.

Implementation Method 1

combustion gases originating from propellants contained in said first and second compartments in said high pressure chamber accelerate the projectile in the firing direction and the countermass in the opposite direction towards a breech

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

said first compartment upholds substantially the originally formed high pressure, preferably ranging from 20 MPa to 60 MPa by means of an opening of said first compartment, preferably a nozzle, delimiting the exhaust of gases from the first compartment to the second compartment

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3559586B1Method and launcher for launching a projectile
Publication Date: 2022.09.21 SAAB AB
  • EP3559586B1 patent drawingFigure 1a~1b
  • EP3559586B1 patent drawingFigure 2a~3a
  • EP3559586B1 patent drawingFigure 3b~3d

AI summary

The invention relates to a method for launching a projectile and a launcher comprising a barrel (1) accommodating a. a projectile (2); b. a rocket motor (13) at the rear end of the projectile (2) comprising a first compartment containing a first propellant; c. a countermass (3) at the rear end of the barrel (1); and d. a second compartment between the rocket motor (13) and the countermass (3) containing a second propellant, wherein said first and second compartments form a high pressure chamber (6) subsequent to firing of the projectile (2).