Projectile Fin Deployment Mechanism for Volume and Drag Reduction
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Solution Overview
Problem
Current control surface deployment mechanisms for projectiles face challenges such as high storage volume requirements, complex designs, and increased aerodynamic drag due to the need for secondary actuators and aerodynamic assistance, especially during extreme accelerations and deployment against the airstream.
Innovation Solution
A control surface deployment apparatus that uses a single actuator for both deployment and guidance, where fins are stowed in a volume-efficient manner parallel to the projectile axis, rotated 90 degrees to minimize aerodynamic load, and then pivoted using a deployment spring to ensure the leading edge remains aligned with the airstream, eliminating the need for secondary actuators and aerodynamic aid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If deployable fins are stowed within the projectile body, then packaging space is reduced, but deployment mechanism complexity increases
Solution Approach 1:
The patent combines the deployment function and guidance control function into a single actuator system. The actuator serves dual purposes: deploying the fins from the stowed position and subsequently controlling their orientation for guidance, eliminating the need for separate deployment mechanisms and reducing overall system complexity
Solution Approach 2:
The single actuator is designed to perform multiple functions: it acts as both a deployment mechanism (extending fins from stowed position) and a control mechanism (adjusting fin orientation during flight). This multi-functionality reduces the number of components needed while maintaining full operational capability
2Reliability
If secondary actuators are used for fin deployment, then deployment reliability improves, but device complexity increases
Solution Approach 1:
The patent merges the deployment actuator and control actuator into a single integrated actuator system. This actuator is designed to perform both deployment and control functions sequentially, reducing component count while maintaining reliability through careful mechanical design that ensures proper sequencing of deployment and control operations
3Reliability
If fins are deployed against the airstream, then aerodynamic assistance is required, but aerodynamic drag increases
Solution Approach 1:
The actuator system performs preliminary deployment action by extending the fins from their stowed position to their operational position before full aerodynamic control is needed. This preliminary mechanical deployment ensures the fins are properly positioned and oriented before aerodynamic forces become the primary control mechanism, reducing the need for high-drag aerodynamic assistance during deployment
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 allows for efficient storage and deployment of fins with reduced aerodynamic drag, freeing up internal volume and simplifying the design, enabling deployment against the airstream without additional assistance, thus enhancing projectile guidance and stability during high accelerations.
Implementation Method 1
a deployment spring rotates about a secondary axis at the base of the fin
Data Source
AI summary
A control surface deployment apparatus having a base part, a drive actuator operably installed adjacent to the base part and having a drive actuator shaft extending beyond the base part, a knuckle part installed on the drive actuator shaft so as to selectively rotate therewith, a hinge part pivotally installed on the knuckle part as through a hinge pin, a fin rigidly installed on the hinge part so as to extend away from the knuckle part, and a spring biasing element configured to pivotally bias the hinge part relative to the knuckle part.