Rolling Collar Ailerons for Spinning Projectile Steering

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Solution Overview

Problem

Existing control systems for spinning and rolling projectiles face challenges in providing precise navigational control due to the danger of premature explosion and imprecise course corrections caused by shock from propulsive outlets and fuels, necessitating an improvement in steering mechanisms.

Innovation Solution

A steering mechanism featuring a rolling collar with ailerons that passively change angle of attack as a function of dynamic pressure, providing circumferential force and lateral steering through elevators, while using a braking mechanism to maintain collar position relative to the fuselage, reducing the need for excessive counter-rotation and energy expenditure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If propulsive outlets, fuels and pyrotechnics are used to produce forces for course correction, then navigational control capability is achieved, but the danger of premature explosion and imprecise course corrections due to shock increases

Engineering Contradiction:
Improvenavigational control capabilityVSAvoidsafety and precision
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the mechanical/chemical propulsive system (outlets, fuels, pyrotechnics) with an aerodynamic system using a collar with ailerons. The ailerons utilize airflow dynamic pressure to generate steering forces, eliminating the need for explosive materials and their associated safety risks while providing smoother, more precise course corrections.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The ailerons are designed to passively change their angle of attack as a function of dynamic pressure. This parameter change allows the steering mechanism to adapt to varying flight conditions automatically, optimizing performance across different speed ranges without requiring active control systems or explosive actuators.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a collar with ailerons is used to provide circumferential force for steering, then steering precision is improved, but energy expenditure increases due to excessive counter-rotation requirements

Engineering Contradiction:
Improvesteering precisionVSAvoidenergy expenditure
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The ailerons are designed with passive dynamic adjustment capability, where the angle of attack changes automatically in response to dynamic pressure variations. This dynamic behavior allows the system to maintain steering precision across different flight phases without requiring excessive counter-rotation energy, as the ailerons naturally adapt their effectiveness to the current flight conditions.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If ailerons passively change angle of attack as a function of dynamic pressure, then energy use is minimized and control efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidailer on mechanism complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The aileron mechanism is designed to be self-regulating, using the dynamic pressure of the airflow itself to adjust the angle of attack. The system serves itself by converting the kinetic energy of the oncoming flow into the appropriate aerodynamic control surface positioning, eliminating the need for external actuators, sensors, or control systems while maintaining energy efficiency.

Inventive Principle:
Principle #25Self-service

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 enables efficient and precise control of spinning projectiles by passively adjusting aileron angles with dynamic pressure, minimizing energy use and avoiding premature explosions, thus improving navigational accuracy and safety.

Implementation Method 1

The ailerons passively change angle of attack as a function of dynamic pressure of the projectile

Methodology Applied
Scientific EffectDynamic pressure: Pressure Increase

Implementation Method 2

The collar includes ailerons that provide a circumferential force on the collar during flight of the projectile

Methodology Applied
Scientific EffectAerodynamic force: Drag

Data Source

PatentEP2748558B1Rolling air vehicle having collar with passively controlled ailerons
Publication Date: 2017.09.06 RAYTHEON CO
  • EP2748558B1 patent drawingFigure 1~2
  • EP2748558B1 patent drawingFigure 3~6
  • EP2748558B1 patent drawingFigure 7~9

AI summary

A spinning, rolling, or roll-stabilized vehicle, such as a projectile (10), includes a fuselage (12) that rotates about its longitudinal axis (spins) during flight. A collar (24) is positionable relative to the fuselage (12) to steer the projectile (10), with the collar (24) having ailerons (28) to provide a roll force to position the collar (24). The collar (24) also has elevators (26) to provide lateral force to steer the projectile (10). The positioning of the collar (24) may be accomplished by moderating the roll force of the ailerons (28) to hold the position of the collar (24) substantially constant with regard to a longitudinal axis of the projectile (10). The ailerons (28) passively change angle of attack with changes in the dynamic pressure of the projectile (10).