Fail-Safe Torque Box Strut Mounting System
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Solution Overview
Problem
Existing torque box strut designs for mounting aircraft engines to wings face structural limitations in narrowing the strut for aerodynamic efficiency due to insufficient space to react to load requirements, and proposed extended designs lack satisfactory fail-safe mechanisms.
Innovation Solution
A mounting apparatus with a strut-to-wing system that includes active and catcher links/catchers for the torque box strut, allowing it to be narrowed while maintaining structural integrity and providing a fail-safe mechanism by engaging catchers upon link failure, utilizing an extended torque box strut with reduced attachment points for improved aerodynamics and reduced loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the torque box strut is made narrower to reduce drag and increase aerodynamic efficiency, then aerodynamic efficiency is improved, but there is insufficient space to react to the required load
Solution Approach 1:
The patent extends the torque box strut aft beyond the engine center of gravity, utilizing the longitudinal dimension to create a longer moment arm. This dimensional extension allows the narrower strut to generate sufficient bending moment to counteract engine weight and loads, resolving the contradiction between narrow width for aerodynamics and sufficient load reaction capability.
2Force
If the upper link is designed to carry excessive load, then the engine is supported during normal operation, but upon upper link failure the other attachments become loaded beyond their intact loading conditions
Solution Approach 1:
The patent incorporates aft link catchers that are pre-positioned to engage automatically upon upper link failure. These catchers are designed beforehand to intercept the torque box strut and prevent it from dropping, cushioning the failure effect and maintaining reliability by preventing catastrophic overload of remaining attachments.
Solution Approach 2:
The patent segments the load path by introducing separate aft link catchers that become active only upon upper link failure. This segmentation isolates the failure mode, allowing the upper link to carry full load during normal operation while the catchers provide dedicated fail-safe support without interfering with normal load paths.
3Reliability
If six strut-to-wing attachments are used with all active under normal flight conditions, then the engine is constrained in all six degrees of freedom, but the torque box strut cannot be made narrower due to structural limitations
Solution Approach 1:
The patent transforms the static six-attachment configuration into a dynamic system where the number of active attachments changes based on operational conditions. During normal flight, only the upper link and diagonal brace are active, while aft link catchers remain inactive. Upon failure, the catchers dynamically engage to provide the necessary constraints, allowing the strut to be narrower while maintaining reliability.
Data Source
AI summary
An apparatus for mounting an aircraft engine to a wing includes a torque box strut for supporting the engine and a mounting system for attaching the torque box strut to the wing. The mounting system has an aft mounting system for attaching the torque box strut to the wing and that has at least one active aft link for attaching the torque box strut to the wing during normal aircraft operation, and at least one aft link catcher for attaching the torque box strut to the wing upon a failure of one of the at least one active aft link. The mounting system has a forward mounting system for attaching the torque box strut to the wing and that has at least one active forward link for attaching the torque box strut to the wing during normal aircraft operation, and at least one forward link catcher for attaching the torque box strut to the wing upon a failure of one of the at least one active forward link.