Aerodynamically Contoured Projectile Base for Rifling-Free Spin
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Solution Overview
Problem
Traditional projectiles impart spin through rifling in gun barrels, leading to friction that causes barrel deterioration, reduced accuracy, and shortened firearm life due to increased wear and tear.
Innovation Solution
Aerodynamically contoured features at the projectile base, such as concave or convex pockets/protrusions, convert propellant forces into rotational and forward motion, allowing the projectile to spin without excessive interaction with the barrel, potentially eliminating the need for rifling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rifling is used to impart spin to the projectile, then projectile stability is improved, but barrel friction increases causing deterioration and shortened firearm life
Solution Approach 1:
The spin-imparting function is extracted from the barrel (rifling) and transferred to the projectile base (aerodynamically contoured features). This eliminates the harmful interaction between rifling and projectile while preserving the beneficial spin effect, thereby extending firearm life without compromising projectile stability
Solution Approach 2:
Instead of the barrel imparting spin to the projectile through rifling, the projectile base features are designed to self-impart spin by interacting with propellant forces. This inversion of the spin-generation mechanism eliminates barrel wear while maintaining projectile stability
2Stability of the object's composition
If rifling is used to impart spin to the projectile, then projectile stability is improved, but friction generates heat and reduces accuracy
Solution Approach 1:
The spin-imparting function is extracted from the barrel and transferred to the projectile base, eliminating the friction-based spin mechanism that generates heat and degrades accuracy. The projectile base features generate spin through aerodynamic forces without harmful frictional contact
Solution Approach 2:
The mechanical friction-based spin generation system (rifling) is replaced with an aerodynamic force-based system (aerodynamically contoured base features). This substitution eliminates the harmful thermal effects of friction while maintaining the stabilizing spin effect, thereby preserving accuracy
3Object-affected harmful factors
If aerodynamically contoured features are added to the projectile base, then barrel friction is reduced, but projectile structure complexity increases
Solution Approach 1:
The projectile base is segmented into distinct aerodynamically contoured features (convex and/or concave) that work together to generate spin. This segmentation allows each feature to be optimized for its specific function while collectively reducing barrel friction without requiring complete redesign of the entire projectile structure
Solution Approach 2:
The projectile base incorporates curved aerodynamically contoured features rather than flat surfaces. These curved features efficiently redirect propellant forces to generate spin while maintaining a relatively simple overall structure that integrates well with conventional projectile designs, minimizing the increase in structural complexity
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 design enhances projectile stability and accuracy by minimizing barrel friction, extending firearm life, and allowing for adjustable spin characteristics, while reducing wear and heat generation, thus enabling higher velocities and prolonged continuous firing.
Implementation Method 1
The features are contoured so that propulsive forces are resolved in such a way as to impart a rotary (spinning) and forwardly-directed motion to the projectile
Data Source
AI summary
A projectile for use in a cartridge having a longitudinal axis, a leading end region, a trailing end region, and a chamber therebetween. The projectile is mounted in the leading end region and has a base. The base of the projectile is provided with one or more aerodynamically contoured features that receive forces generated by a propellant. The aerodynamically contoured features are concave or convex or are a combination of concave and convex so that some of the forces produce forwardly directed and rotational motion of the projectile.