Aft Engine Mount Coupling for Turboprop Torque Split Control
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Solution Overview
Problem
Conventional engine mounts struggle to achieve the desired torque split in multi-plane support systems for turboprop and turboshaft engines, often resulting in excessive stress and performance loss due to inadequate torque restriction at aft mounting planes, especially when the airframe structure is not stiff enough.
Innovation Solution
The engine mount system employs multiple coupling elements that react forces in vertical and lateral directions while allowing unrestricted rotation about the engine's axis, using a combination of mechanical and fluidic components to decouple torque reaction from the mounting planes, thereby providing low or insignificant torque reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional mounts with isolation systems are used to achieve torque split, then torque reaction distribution can be controlled, but the airframe structure may dominate the overall flexibility and prevent achieving desired torque split when structure is not stiff enough
Solution Approach 1:
The patent introduces an intermediary mechanism (the aft mount coupling elements) that mediates between the engine and the airframe structure. This intermediary allows the system to achieve the desired torque split (85% or more at the forward plane) even when the airframe structure itself is not sufficiently stiff, by actively managing the torque distribution through the coupling elements rather than relying solely on structural stiffness.
Solution Approach 2:
The patent changes the parameters of the mounting system by using coupling elements with specific stiffness characteristics that can be independently controlled. By adjusting the stiffness parameters of the aft mount coupling elements, the system can achieve the desired torque split regardless of the airframe structure's inherent flexibility, effectively decoupling the torque distribution control from the structural stiffness requirements.
2Stability of the object's composition
If stiff isolators are used to achieve torque split, then torque reaction can be properly distributed, but the supporting airframe structure may not be stiff enough to provide adequate support
Solution Approach 1:
The patent segments the torque reaction function across two distinct mounting planes (forward and aft). The forward mount is designed to react greater than 85% of the engine torque, while the aft mount with its coupling elements handles the remaining torque and provides additional support functions. This segmentation allows the system to achieve proper torque distribution without requiring the entire airframe structure to be uniformly stiff.
Solution Approach 2:
The coupling elements at the aft mount serve as intermediaries that provide adequate support capability without transferring the full burden to the airframe structure. These coupling elements act as a buffer that ensures sufficient support is provided while maintaining the desired torque split, effectively mediating between the engine loads and the airframe structure's support capacity.
3Stability of the object's composition
If torque reaction is shared across multiple mounting planes, then support distribution is improved, but twisting moments are generated that stress the engine and cause performance loss
Solution Approach 1:
The patent applies local quality by concentrating the torque reaction function primarily at the forward mounting plane (85% or more of total torque), while the aft mounting plane with its coupling elements provides localized support and stability functions. This non-uniform distribution of functions minimizes twisting moments on the engine while maintaining adequate support distribution across multiple planes.
Solution Approach 2:
Instead of distributing torque evenly across multiple planes (the conventional approach), the patent inverts the approach by concentrating torque reaction at the forward plane and using the aft coupling elements primarily for support and stability. This inverted torque distribution strategy reduces engine twisting moments while maintaining multi-plane support benefits.
Data Source
AI summary
Aft-mounting systems, devices, and methods for turboprop and turboshaft engines include two or more coupling elements 201, 211, 221 that are configured to couple an aft portion of an engine of an aircraft to a support structure of the aircraft. The two or more coupling elements are together configured to react forces generated in a vertical direction and in a lateral direction transverse to the engine but allow substantially unrestricted rotation of the engine with respect to the support structure about an axis of rotation of the engine.