Supercavitating Bullet Geometry for Underwater Range and Stability
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Solution Overview
Problem
Conventional bullets experience reduced effective range and accuracy when used underwater due to excessive vortex generation and deformation under water pressure, which shortens range and deteriorates accuracy.
Innovation Solution
The bullet design incorporates a hemispherical front end, a recessed curved rear surface, an inclined portion, and a stepped portion to generate and maintain super cavitation, reducing water resistance and increasing the cavity size between the bullet and water, along with fluid inducing grooves to stabilize flight and prevent shaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a deep groove is formed in the rear surface of the bullet to fill gunpowder, then the effective range and accuracy are improved when shot in air, but excessive vortex is generated when used underwater
Solution Approach 1:
The patent applies local quality by creating different surface structures in different regions of the bullet. The front surface has a smooth curved shape to minimize vortex generation underwater, while the rear surface contains grooves for gunpowder injection. This regional differentiation allows the bullet to achieve both aerodynamic performance in air and hydrodynamic performance underwater without the deep rear groove causing excessive vortex.
2Power
If the jacket is expanded by explosive power to increase contact with the barrel, then the explosive power is effectively transferred to the bullet, but the jacket is contracted by water pressure underwater causing lead to push to the rear side and deform the jacket
Solution Approach 1:
The patent applies preliminary action by pre-hardening the jacket material through selective heat treatment or alloy composition modification in regions susceptible to water pressure contraction. This preliminary structural reinforcement prevents the jacket from deforming when subjected to water pressure, maintaining the bullet's structural integrity and accuracy underwater while still allowing effective explosive power transfer during firing.
3Force
If super cavitation is generated by forming a stepped portion or inclined surface at the front of the bullet, then water resistance is reduced and effective range is improved, but the cavity size reduces as the bullet slows down and water contacts the outer surface
Solution Approach 1:
The patent applies spheroidality by designing the front surface of the bullet with a smooth curved profile rather than sharp edges or flat surfaces. This curved geometry promotes the formation and maintenance of a stable cavitation bubble that adheres to the bullet surface for a longer duration. The gradual curvature transition prevents premature cavity collapse, allowing super cavitation to be maintained even as the bullet decelerates, thereby extending the effective range.
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 effectively generates and sustains super cavitation for longer, significantly increasing the bullet's effective range and accuracy both in air and underwater by reducing water resistance and maintaining stability during flight.
Implementation Method 1
the air inducing groove formed in a rear side of the bullet to generate turbulence and prevent the bullet from being shaken
Implementation Method 2
the super cavitation may be more effectively generated by the front end portion, the recess portion, the inclined portion, and the stepped portion, which are provided on the bullet, to significantly increase the size of the cavity between the surface of the bullet and the water
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
The present invention relates to a bullet with an increased effective range. The bullet includes a front end portion (10) having a hemispherical shape, a recess portion (20) connected to a rear end of the front end portion (10) and having a curved surface that is recessed inward, an inclined portion (30) connected to a rear end of the recess portion (20) and inclined at a predetermined angle (A) with respect to a horizontal line, a stepped portion (40) connected to a rear end of the inclined portion (30) and inclined at a predetermined angle (A') with respect to the horizontal line, and fluid inducing grooves formed from the rear to a rear end surface of the bullet (1). Thus, when the bullet passes through underwater, super cavitation may be more effectively generated and maintained for even longer to significantly increase the effective range of the bullet.