Projectile Base Drag Reduction Fairing via Plastic Deformation
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Solution Overview
Problem
Existing projectiles face challenges in reducing base drag, which affects their range, and base bleed generators used to mitigate this issue often complicate compliance with insensitive munitions requirements due to the use of easily ignitable fuels.
Innovation Solution
Deployment of a base drag reduction fairing achieved through plastic deformation of a preform within the projectile, which extends the projectile's length and reduces drag, potentially combined with a base bleed system using a gas generator to fill the vacuum behind the projectile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If base bleed generators are used to reduce base drag, then base drag is reduced, but the projectile cost increases and the volume available for other content is reduced
Solution Approach 1:
The patent extracts the base drag reduction function from a complex base bleed generator system and implements it through a simple geometric modification - a boat-tail shaped base. This eliminates the need for fuel storage and ignition systems while achieving the same base drag reduction effect.
Solution Approach 2:
The patent replaces expensive, complex base bleed fuel systems with a simple, inexpensive geometric structure that is permanently integrated into the projectile base. The boat-tail shape provides lasting base drag reduction without requiring consumable fuel materials.
2Loss of energy
If base bleed generators using easily ignitable fuels are used, then base drag is reduced, but compliance with insensitive munitions requirements is compromised
Solution Approach 1:
The patent removes the easily ignitable fuel component entirely from the base drag reduction system. By using a purely geometric boat-tail base design, the system achieves base drag reduction without any combustible materials that would conflict with insensitive munitions requirements.
Solution Approach 2:
The patent eliminates the need for base bleed fuel materials by using a permanent geometric structure. This geometric solution is both compliant with insensitive munitions requirements and economically superior, as it eliminates fuel storage and handling complexities.
3Loss of energy
If the rear shape of the projectile is modified to reduce base drag, then base drag is reduced, but the device complexity increases
Solution Approach 1:
The patent applies a localized geometric modification only to the base region of the projectile, creating a boat-tail shape. This local modification optimizes base drag reduction without requiring complex modifications to the rest of the projectile structure, maintaining simplicity while achieving the desired performance improvement.
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 increases the range of projectiles by 7% to 17% without the need for expensive base bleed fuel, while maintaining compliance with insensitive munitions requirements by avoiding easily ignitable materials.
Implementation Method 1
a base drag reduction fairing achieved through plastic deformation of a preform within the projectile
Implementation Method 2
a base bleed system using a gas generator to fill the vacuum behind the projectile
Data Source
AI summary
A projectile may include a base drag reduction fairing preform adapted to be plastically deformed into a base drag reduction fairing after the projectile is launched from a gun barrel.