Linear Thrust Deflectors for Missile Attitude Control
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Solution Overview
Problem
Aerodynamic control surfaces are ineffective at low velocities and high altitudes, necessitating the use of thrust vectoring for missile attitude control, which requires complex actuation mechanisms for rotating thrust deflector devices within the rocket motor exhaust stream.
Innovation Solution
The implementation of a system with independently extendable and retractable thrust deflectors, positioned at intervals around the nozzle, which generate transverse forces and torques to control the missile's attitude and roll without reducing thrust efficiency, using linearly-positionable, non-rotatable vanes or asymmetric pins to produce desired forces and torques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thrust vectoring devices are extended into the motor exhaust stream to control attitude at low velocities and high altitudes, then attitude control capability is improved, but device complexity increases due to complex actuation mechanisms required for rotation and withdrawal
Solution Approach 1:
The thrust vectoring function is segmented into multiple independently controllable deflectors (first deflector, second deflector, third deflector, fourth deflector) positioned at different locations around the exhaust stream. Each deflector can be independently extended or retracted, allowing complex attitude control to be achieved through simple linear movements of multiple simple components rather than complex rotation of a single component.
Solution Approach 2:
Instead of rotating the entire nozzle or using rotatable deflectors within the exhaust stream (conventional approach), the invention uses fixed, non-rotatable deflectors that are extended or retracted linearly. This inverts the conventional approach by using linear positioning of multiple simple deflectors rather than rotational movement of complex mechanisms, thereby simplifying the actuation system while maintaining attitude control capability.
2Adaptability or versatility
If rotatable thrust deflector devices are used within the rocket motor exhaust stream, then thrust vectoring for pitch and yaw control is achieved, but thrust efficiency is reduced due to devices extending into the exhaust stream
Solution Approach 1:
The deflectors are designed to be dynamically extendable and retractable, allowing the system to adapt its configuration based on operational requirements. When thrust efficiency is prioritized, deflectors can be retracted from the exhaust stream. When attitude control is needed, deflectors are extended to the required positions, providing dynamic optimization of both thrust efficiency and control capability.
Solution Approach 2:
The deflectors are positioned and oriented in advance during design to achieve the desired thrust vectoring effects. The first and second deflectors are positioned to control pitch, while the third and fourth deflectors control yaw. This preliminary positioning eliminates the need for complex real-time rotation during operation, maintaining thrust efficiency while achieving precise attitude control.
3Speed
If aerodynamic control surfaces are used for missile attitude control, then control is effective at high velocities, but control becomes ineffective at low velocities and high altitudes
Solution Approach 1:
The thrust deflector system serves multiple functions: it provides attitude control at low velocities where aerodynamic surfaces are ineffective, maintains thrust efficiency when retracted, and can be combined with aerodynamic control surfaces for comprehensive control across the entire operational envelope. This multi-functionality ensures reliable control throughout all phases of missile flight from launch to high-speed cruise.
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 precise control of the missile's attitude and roll using thrust vectoring, maintaining thrust efficiency and simplifying the actuation mechanism by eliminating the need for complex rotation within the exhaust stream, effectively addressing the limitations of aerodynamic control at low velocities and high altitudes.
Implementation Method 1
thrust vectoring is defined as directing the thrust of a rocket motor or jet engine in a direction that is not parallel to a longitudinal axis of the missile
Implementation Method 2
a rocket motor that produces thrust by ejecting combustion gases through the nozzle
Data Source
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AI summary
An apparatus for vectoring the thrust of a motor that produces thrust along a longitudinal axis by expelling combustion gases through a nozzle may include a plurality of linearly-positionable non-rotatable thrust deflectors. The thrust deflectors may be disposed at around a perimeter of the nozzle. Each thrust deflector may be independently extended to simultaneously generate both a force transverse to the longitudinal axis and a torque about the longitudinal axis.