Thrust Vectoring via Boundary Layer Control
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Solution Overview
Problem
Current thrust vectoring systems for jet engines are limited in application to supersonic aircraft and require significant secondary power, making them inefficient for subsonic aircraft and adding weight, which complicates flight control and maneuverability.
Innovation Solution
A thrust vectoring system that employs a flight control surface with a secondary fluid flow to generate non-axial forces by influencing the boundary layer of the primary exhaust flow, using a combination of slots and actuators to direct secondary airflows normal or tangentially to the surface, enhancing attachment or separation of the boundary layer for control of aircraft attitude and flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional thrust vectoring systems are used, then non-axial forces can be generated for flight control, but the systems are limited to supersonic aircraft and require significant secondary power
Solution Approach 1:
The patent changes the operating parameters of the flow control system by using a constant area nozzle instead of convergent-divergent nozzle, and by adjusting the position and dimensions of the flow control surface. This allows the system to operate efficiently on subsonic aircraft while maintaining the ability to generate non-axial forces for flight control, thereby resolving the contradiction between adaptability and energy consumption
Solution Approach 2:
The patent employs a simplified version of the flow control concept by using a constant area nozzle configuration rather than the complex convergent-divergent nozzle. This copying of the essential flow control function in a simplified form enables the system to work on subsonic aircraft with reduced power requirements, addressing both adaptability and energy consumption concerns
2Force
If convergent-divergent nozzles are used for thrust vectoring, then non-axial forces can be generated, but large performance penalties occur for subsonic aircraft
Solution Approach 1:
The patent modifies the nozzle geometry parameter from convergent-divergent to constant area configuration. This parameter change allows the nozzle to maintain its thrust vectoring capability while avoiding the performance penalties associated with convergent-divergent nozzles on subsonic aircraft, thus resolving the contradiction between force generation and productivity
Solution Approach 2:
The patent segments the flow control function from the nozzle structure by placing a separate flow control surface within the constant area nozzle. This segmentation allows the nozzle to maintain its simple constant area geometry for efficient subsonic operation while the separate flow control surface provides the necessary non-axial force generation capability
3Ease of operation
If flight control surfaces are added to achieve maneuverability, then aircraft controllability improves, but aircraft weight increases
Solution Approach 1:
The patent makes the flow control surface multi-functional by enabling it to perform both thrust vectoring and flight control functions. The same surface that generates non-axial forces for thrust vectoring can also be used for pitch, roll, and yaw control, thereby improving ease of operation without requiring additional separate control surfaces that would increase aircraft weight
4Force
If entire exhaust nozzle outer flow path is deflected for thrust vectoring, then non-axial forces are generated, but significant secondary power is required
Solution Approach 1:
The patent applies local quality by concentrating the flow control action at a specific location within the nozzle rather than deflecting the entire outer flow path. The flow control surface is positioned to locally alter the exhaust flow patterns, generating the necessary non-axial forces with minimal secondary power input, thus resolving the contradiction between force generation and power consumption
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 system enables efficient generation of non-axial forces for controlling aircraft attitude and flight with reduced power consumption and weight, offering rapid response and increased maneuverability for both supersonic and subsonic aircraft, with potential for reduced size and cost of flight control surfaces.
Implementation Method 1
A secondary fluid flow is created adjacent the flight control surface that influences a boundary layer of the fluid flow over the flight control surface
Implementation Method 2
The secondary airflows may be directed either normal or tangential to an outer surface of the airfoil, to thus selectively enhance separation or attachment, respectively, of a boundary layer of the primary flow moving over the flap
Data Source
AI summary
A method and system for thrust vectoring a primary fluid flow from an exhaust nozzle of a jet engine that significantly increases the non-axial force able to be generated by a flight control surface associated with the nozzle. In one implementation the method involves placing a flight control element having a movable portion adjacent a downstream edge of the nozzle. A secondary fluid flow is created adjacent a surface of the flight control element that influences a boundary layer of the primary fluid flow over the flight control element. This causes the primary fluid flow to generate a force that is directed non-parallel (i.e., non-axial) to a longitudinal axis of the nozzle. In one specific implementation a plurality of slots are formed in the flight control surface, and the flight control surface is formed by an airfoil. In another implementation the flight control surface is formed on an interior wall of the nozzle at a downstream edge of the nozzle. In various implementations either a pressurized secondary fluid flow can be directed out through the slot, or a vacuum force can be generated through the slot to either promote attachment or separation of the primary fluid flow passing over the flight control surface.