Asymmetric Vane Geometry for Nose-Up Pitch Control
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Solution Overview
Problem
Conventional thrust reverser systems for turbine engines generate an undesirable nose-up pitch moment during reverse thrust, which can reduce aircraft control and safety, particularly in aircraft with engines mounted high on the fuselage, necessitating thrust reduction to mitigate this effect.
Innovation Solution
A thrust reverser system employing asymmetric vane geometry within the transcowl aperture, where the upper and lower portions of the vane assembly are designed to produce a vertical thrust component, offsetting the nose-up pitch moment while maintaining a single row configuration to minimize weight and material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional symmetric thrust reverser systems are used, then reverse thrust is generated for deceleration, but an undesirable nose-up pitch moment is produced that reduces aircraft control
Solution Approach 1:
The patent applies asymmetry by configuring the upper and lower vane assemblies with different geometric parameters. Specifically, the upper vane assembly has a different angle of attack and/or camber compared to the lower vane assembly, creating an asymmetric flow deflection pattern that generates a vertical thrust component to counteract the nose-up pitch moment while maintaining reverse thrust for deceleration
2Force
If multiple rows of cascade vanes are used to generate reverse thrust, then deceleration effectiveness is improved, but weight and material cost increase
Solution Approach 1:
The patent segments the vane assembly into an upper portion and a lower portion with distinct geometric configurations. This segmentation allows each portion to be optimized for its specific function while using a single row of vanes in each portion, reducing the overall material requirements compared to traditional multi-row cascade vane systems while maintaining effective reverse thrust generation
3Use of energy by moving object
If engines are mounted high on the fuselage to improve aerodynamics, then aerodynamic performance is improved, but the nose-up pitch moment during reverse thrust is exacerbated
Solution Approach 1:
The patent applies preliminary anti-action by designing the asymmetric vane geometry to pre-compensate for the nose-up pitch moment caused by high engine mounting. The asymmetric configuration is specifically tailored to generate a vertical thrust component that counteracts the pitch moment before it can adversely affect aircraft control, allowing high engine mounting to be maintained for aerodynamic benefits
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
The asymmetric vane geometry effectively generates a vertical thrust component that counteracts the nose-up pitch moment, enhancing aircraft control and safety without increasing weight or material costs, while maintaining the deceleration benefits of reverse thrust.
Implementation Method 1
an asymmetric vane assembly disposed within the aperture and configured such that an upper portion of the asymmetric vane assembly is asymmetric with respect to a lower portion of the asymmetric vane assembly, thereby generating a desired vertical thrust component based on the reverse thrust
Data Source
AI summary
A thrust reverser system having an asymmetric vane assembly is provided. The provided thrust reverser system generates a desired vertical thrust component that at least partially offsets a potential nose-up pitch moment. The provided thrust reverser system employs a single row asymmetric vane geometry that reduces weight and material cost.