Tail Thruster Control for Projectile Guidance
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Solution Overview
Problem
Current projectile guidance systems, particularly for mortars, face challenges in surviving extreme launch environments and constrained volumes, limiting the effectiveness of mechanically controlled rear lifting elements, which reduces maneuver capability and requires separation of the fuse and arm system, making guided rounds less suitable for rapid, scattered impacts.
Innovation Solution
A tail-mounted guidance kit using thrusters to control body angle of attack and lift, implemented on a screw interface, with a nozzle system and pressurized gas to guide projectiles, allowing field selection between guided and unguided modes, and incorporating flip-out surfaces and strakes to enhance lift and maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanically controlled rear lifting elements are used, then maneuver capability is improved, but the system cannot survive extreme launch environments and constrained volumes
Solution Approach 1:
The patent replaces mechanically controlled lifting surfaces with a cold gas thruster system. The thruster uses pressurized gas stored in a tank to provide controlled thrust for maneuvering, eliminating the need for complex mechanical linkages, motors, and control surfaces that cannot survive the extreme launch environment. The gas thruster system is far more reliable in this context.
Solution Approach 2:
The patent employs a pneumatic system using cold gas (typically nitrogen) stored under pressure in a tank. The gas is released through a valve and nozzle to generate thrust for controlling the projectile's attitude and trajectory. This pneumatic approach provides reliable actuation without the mechanical complexity that fails in launch environments.
2Force
If flip out surfaces are added to enhance tail area, then lift is improved, but the volume required for motors and mechanism reduces available lift and complicates the constrained volume
Solution Approach 1:
The patent eliminates the need for flip-out surfaces and their associated motors by using a cold gas thruster system. The thruster provides all necessary maneuvering force without requiring additional tail area or complex deployment mechanisms, thus avoiding the volume trade-off entirely.
3Adaptability or versatility
If guidance system is added to the nose, then guidance capability is improved, but the fuse and arm system are decoupled requiring integral guidance package
Solution Approach 1:
The patent segments the guidance system into two independent parts: (1) a tail kit with thruster for guidance control, and (2) the existing nose fuse/arm system. This allows the guidance functionality to be added without modifying the fuse, maintaining the ability to use standard fuses and preserving field replaceability. The tail kit attaches to the rear of the projectile and provides all guidance functions independently.
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 provides a capable and cost-effective guidance system that maintains safety by not modifying the fuse, enhances lift and maneuverability, and allows for field selection between guided and unguided modes, improving the precision and effectiveness of projectile guidance in challenging environments.
Implementation Method 1
A gas tank in the boom assembly contains pressurized gas. The gas can be a pressurized cold gas. A valve lets a pulse of gas out of the gas tank. A nozzle expels the pulse of gas to control an angle of attack
Implementation Method 2
Lift is generated by controlling the body angle of attack. Lifting elements in front of the center of gravity (CG) are used to control the body angle of attack which also generates additive lift
Data Source
AI summary
A system and method for guiding a projectile is presented. A method for guiding a projectile includes storing a gas in a chamber that is attached to the projectile. The projectile has an explosive front end and a rear guidance kit consisting of a body extension and a tail boom. The chamber is located in the body extension with the control electronics. Two or more fins that are configured to stabilize the projectile while the projectile is in flight. Pulses of gas are released out of the chamber through a nozzle at the end of the tail boom to control an angle of attack to control the lift of the projectile to guide the projectile to a target while the projectile is in flight.