Thrust Reverser Cascade Nested in Translating Sleeve
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Solution Overview
Problem
Aircraft thrust reverser cascades face challenges in fitting an aerodynamically well-designed structure within constrained nacelle spaces due to the need to maintain external and internal loft lines, making it difficult to redirect air effectively for reverse thrust during landing.
Innovation Solution
A thrust reverser system comprising a torque box, an aft cascade ring, and a cascade with a first vane set at a constant radius and a second vane set with varying radial positions relative to the engine centerline, allowing the cascade to fit within confined spaces while maintaining performance by translating a sleeve to expose the cascade for air diversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional aerodynamically well-designed cascade structure is used, then air redirection performance is improved, but it cannot fit within the constrained nacelle space
Solution Approach 1:
The cascade structure is nested within the translating sleeve assembly, which itself is contained within the nacelle. The cascade can be exposed by translating the sleeve outward, allowing the compact nested design to provide full cascade functionality when needed while maintaining a compact stowed profile.
Solution Approach 2:
The cascade structure is made dynamically deployable through the translating sleeve mechanism. The cascade transitions from a retracted position (nested within the sleeve) to an extended position (exposed for air redirection), allowing the system to adapt its effective volume based on operational requirements.
2Volume of moving object
If the cascade is designed to fit within constrained nacelle space, then space utilization is improved, but aerodynamic performance deteriorates
Solution Approach 1:
The cascade structure transitions from a compact nested state to a fully extended aerodynamic configuration when the translating sleeve moves outward. This dynamic deployment allows the cascade to achieve its full aerodynamic potential during thrust reverser operation while maintaining a compact profile during normal flight.
Solution Approach 2:
The thrust reverser system is segmented into the cascade structure and the translating sleeve assembly. This segmentation allows the cascade to be optimized for aerodynamic performance when exposed, while the sleeve provides the mechanical deployment function, separating the aerodynamic and mechanical design optimization.
3Device complexity
If a compact cascade design is used to fit nacelle space, then device complexity is reduced, but aerodynamic effectiveness deteriorates
Solution Approach 1:
The cascade structure employs dynamic deployment through the translating sleeve, transitioning from a compact low-complexity stowed position to a fully extended high-aerodynamic-effectiveness position. This dynamic approach allows a relatively simple nested structure to deliver complex aerodynamic functionality when deployed.
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 the cascade to fit within constrained nacelle spaces while maintaining aerodynamic performance and facilitating air diversion for reverse thrust, improving the integration of thrust reverser systems in aircraft engines.
Implementation Method 1
facilitating air diversion for reverse thrust
Data Source
AI summary
A thrust reverser system may comprise a cascade radially positioned about a centerline of an engine or a nacelle centerline. Various cascade features may be positioned at a constant radius from the centerline while other features vary according to station and/or circumferential position.