Aft Engine Mount Coupling for Low Torque Reaction in Turboprops
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Solution Overview
Problem
Conventional engine mounts for turboprop and turboshaft engines face challenges in restricting engine torque reaction to a single attachment plane, leading to twisting moments and stress on the engine, which can result in performance loss, especially when the airframe structure is not stiff enough to support a stiff isolator.
Innovation Solution
The engine mount system employs a configuration with multiple attachment planes, using a combination of mechanical and fluidic components to provide low torque reaction while maintaining translational stiffness, allowing for unrestricted rotation and decoupling roll-moment reaction from vertical and lateral load reactions, thereby minimizing torque reaction at the mounting planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stiff isolators are used to restrict torque reaction to one attachment plane, then torque reaction restriction is improved, but the device becomes inapplicable when airframe structure is not stiff enough
Solution Approach 1:
The patent changes the stiffness parameter of the isolator from high (conventional) to low, creating a compliant isolator that adapts to airframe structures with varying stiffness levels while still effectively restricting torque reaction to the forward attachment plane
Solution Approach 2:
The isolator is designed with dynamic compliance, allowing it to flex and adapt to the specific stiffness characteristics of different airframe structures while maintaining its torque reaction restriction function across various installation conditions
2Stability of the object's composition
If multiple attachment planes are used to support the engine, then support stability is improved, but torque reaction is distributed causing twisting moments in the engine
Solution Approach 1:
The patent applies different isolator characteristics to different attachment planes: the forward plane uses a stiff isolator to restrict torque reaction, while the aft plane uses a compliant isolator that allows torque freedom, thereby preventing twisting moments while maintaining support stability
Solution Approach 2:
The engine support system is segmented into distinct forward and aft attachment planes with different isolator stiffness characteristics, allowing independent optimization of torque reaction restriction at each plane while maintaining overall support stability
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 configuration effectively reduces torque reaction at the mounting planes, preventing engine stress and maintaining performance by allowing for flexible attachment and vibration isolation, regardless of the airframe stiffness, thus ensuring stable engine operation.
Implementation Method 1
a fluid torque restraint system configured to react differential loads on either side of the engine
Implementation Method 2
an elastomeric element configured to resiliently couple the inner member to the fluid torque restraint system
Data Source
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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.