Slip Baseplate for Rifled Launch Tube Spin Isolation
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Solution Overview
Problem
Current ammunition projectiles with onboard guidance and control systems face issues when launched from rifled tubes, as they spin uncontrollably due to the rifling, interfering with the G & C systems and resulting in inconsistent performance, high firing signatures, and excessive gas bypassing.
Innovation Solution
A slip baseplate with annular shaped elements, including ball bearings, is used between a bolt plate and a nut plate to mechanically isolate the spin rate of the guidance and control unit payload, reducing the spin rate of the carrier assembly during launch from a rifled gun tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional rifled launching tube is used to launch a projectile with G & C system, then the projectile can be launched with high muzzle velocity, but the G & C system will spin uncontrollably and interfere with its operation
Solution Approach 1:
The baseplate is divided into two independently rotating components: an outer rotatable baseplate that engages with the rifling and rotates at high speed, and an inner carrier assembly that remains relatively non-rotating. This segmentation allows the projectile to be launched from a rifled tube while isolating the G & C system from excessive spin rates.
Solution Approach 2:
The slip interface between the outer baseplate and inner carrier assembly acts as an intermediary that decouples the rotational motion. The inner carrier assembly slips relative to the outer baseplate, allowing the outer plate to rotate with the rifling while the inner carrier and G & C system experience minimal rotation.
2Reliability
If a slip obturator ring is used to minimize initial spin rate, then the G & C system spin rate is reduced, but there is inconsistency, fragmentation at gun exit, and excessive bypassing gases
Solution Approach 1:
The baseplate assembly combines different materials with complementary properties: the outer rotatable baseplate is made of metal to withstand high stresses and engage with rifling, while the inner carrier assembly uses low-friction materials (such as PTFE or other lubricants) at the slip interface to minimize rotation and prevent fragmentation.
Solution Approach 2:
The obturator ring incorporates a curved or conical slip surface that guides the inner carrier assembly smoothly through the outer baseplate during launch. This curved geometry ensures consistent spin rate reduction while maintaining proper sealing to prevent excessive gas bypassing.
3Speed
If plastic slip obturator rings are used to reduce spin rate, then initial spin is minimized, but there is still fragmentation, high firing signature, and poor obturation performance
Solution Approach 1:
The baseplate assembly combines different materials with complementary properties: the outer rotatable baseplate is made of metal to withstand high stresses and engage with rifling, while the inner carrier assembly uses low-friction materials (such as PTFE or other lubricants) at the slip interface to minimize rotation and prevent fragmentation.
Solution Approach 2:
The obturator ring is designed as a disposable component that performs its sealing and spin-reduction function during launch, then remains in the launcher or is discarded. This allows optimization for single-use performance rather than durability, enabling effective gas sealing and spin rate control without concern for reuse.
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 solution minimizes initial spin rate, maximizes gun pressure, reduces bypassing gas, and lowers firing signatures, ensuring consistent muzzle velocity and effective operation of the G & C systems.
Implementation Method 1
annular shaped elements comprising ball bearings (5 and 15) in between the two annular shape plates (bolt plate 3 and nut plate 2) to maximize their independency in motion
Data Source
AI summary
A rear slip base plate for a round carrying a guidance and control unit payload, which round is launched from a rifled launch tube. To prevent the guidance and control unit payload from also being rapidly spun with the round, the slip base plate unit mechanically isolates the guidance and control unit payload from the round spin rate.