Ramjet Projectile Axial Control Module for Precision Guidance

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Solution Overview

Problem

Artillery projectiles propelled by ramjets lack the ability to control their trajectory, making it difficult to achieve precision over long ranges or varying flight times, as existing trajectory correction methods are not compatible with the geometry and aerodynamics of ramjet projectiles.

Innovation Solution

A projectile design featuring a deployable tail and a control module that can move axially to block the air inlet, containing canard control surfaces, which can be deployed to correct the trajectory by controlling the ramjet's operation time and extending the projectile's range beyond conventional limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If trajectory correction control surfaces are installed on the projectile nose cone, then trajectory precision is improved, but the geometry and aerodynamics of the ramjet air intake are compromised

Engineering Contradiction:
Improvetrajectory precisionVSAvoidair intake geometry
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control surfaces are relocated from the nose cone (front dimension) to the rear base of the projectile (back dimension), specifically positioned on the external surface of the rear base. This spatial relocation allows trajectory correction functionality to be maintained while preserving the clean aerodynamic geometry of the ramjet air intake, as the control surfaces are now positioned away from the intake flow path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The control system is segmented into separate functional elements: the ramjet air intake remains as a distinct, optimized component, while the trajectory correction function is separated into independent control surfaces mounted on the rear base. This segmentation allows each component to be optimized independently - the air intake for aerodynamic efficiency and the control surfaces for trajectory precision - without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the air inlet is blocked to stop the ramjet, then the projectile can be guided precisely, but the propulsion function is terminated

Engineering Contradiction:
Improveguidance precisionVSAvoidpropulsion duration
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The air inlet is designed with dynamic controllability, allowing it to transition between open and blocked states. During the propulsion phase, the air inlet remains open to maintain ramjet operation. When trajectory correction is required, the air inlet can be blocked to terminate propulsion and enable precise guidance. This dynamic state change allows the system to adapt its propulsion function based on operational needs while maintaining guidance precision when required.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control surfaces are deployed in advance before the air inlet is blocked, allowing the projectile to begin trajectory correction maneuvers while still propelled. This preliminary deployment of control surfaces ensures that guidance precision can be achieved immediately upon inlet blocking, without delay, and allows the propulsion to be terminated at the optimal moment for achieving the desired trajectory correction.

Inventive Principle:
Principle #10Preliminary action

3Length of stationary object

If the range is extended beyond conventional limits, then the strategic capability is improved, but the ballistic dispersion increases significantly

Engineering Contradiction:
ImproverangeVSAvoidballistic dispersion
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The system incorporates feedback control through the deployed control surfaces that can adjust their position and orientation based on real-time trajectory deviations. This feedback mechanism allows the control surfaces to compensate for ballistic dispersion effects, maintaining precision even as the range is extended beyond conventional limits. The feedback control continuously corrects deviations, ensuring accurate delivery despite the increased range.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control surfaces enable dynamic changes in the projectile's flight parameters, such as angle of attack, pitch, and roll, to optimize the trajectory. By actively adjusting these parameters during flight, the system can compensate for aerodynamic and gravitational effects that would otherwise cause increased dispersion at long ranges. This parameter control allows the projectile to maintain precision while achieving extended range capabilities.

Inventive Principle:
Principle #35Parameter changes

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

Enables precision guidance and extended range capabilities for artillery projectiles, allowing for metric precision independent of flight time or range, using conventional artillery and existing firing charges, with improved aerostabilization and reduced mechanical constraints.

Implementation Method 1

a chamber (6) in which is housed an ablatable annular semi-propellant block (7)

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

the pilot module being able to be moved axially by a motor means, during the flight of the projectile and at a defined instant on the trajectory, called the extinction instant, from a rear position in which it does not block the air inlet, to a front position in which it blocks the air inlet

Methodology Applied
Scientific EffectPhysical blockage:

Implementation Method 3

the pilot module containing at least two canard control surfaces which can be deployed outside the projectile after blocking the air inlet

Methodology Applied
Scientific EffectAerodynamic control: Aerofoil

Implementation Method 4

the pilot module being able to be moved axially by a motor means

Methodology Applied
Scientific EffectMechanical actuation:

Data Source

PatentEP3788249B1Ramjet-propelled projectile
Publication Date: 2024.12.11 KNDS AMMO FRANCE
  • EP3788249B1 patent drawingFigure 1~3a
  • EP3788249B1 patent drawingFigure 3b~4b
  • EP3788249B1 patent drawingFigure 4c~6

AI summary

The subject of the invention is a ramjet-propelled projectile (1), the projectile comprising an outer body (2) and a deployable tail-fin assembly (3), the projectile comprising inside the body a chamber housing an abradable annular block of semi-solid propellant (7), and a casing (8) containing a warhead. This projectile is characterized in that it comprises a control module (12) located axially and which extends through an air intake (11), the control module being able to be moved longitudinally by a drive means, while the projectile is in flight and at a defined moment in the trajectory, referred to as flameout, from an aftwards position in which it does not block the air intake (11) towards a forward position in which it blocks the air intake, the control module (12) containing at least two canard control surfaces (15) which can be deployed out from the projectile (1) after the air intake (11) has been blocked.