Aircraft Thrust Reverser Hinge With Misaligned Pin for Smooth Flow
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Solution Overview
Problem
Conventional thrust reversers in aircraft propulsion systems require a 'bump out' or 'blister' feature due to the alignment of the hinge pin with the hinge line, which distorts the inner flow surface and affects aerodynamic performance and aesthetics.
Innovation Solution
The use of a spherical bearing at the blocker door hinge allows the hinge pin to be misaligned with the hinge line, enabling the hinge pin to fit within the ideal aerodynamic flow surface, eliminating the need for bump outs or blisters and improving packaging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hinge pin is aligned with the hinge line in conventional thrust reversers, then the blocker door can pivot properly between forward and reverse positions, but a bump out or blister fairing is required that distorts the inner flow surface and degrades aerodynamic performance
Solution Approach 1:
The patent relocates the hinge pin from the traditional in-plane position to a position offset in a third dimension (radially outward from the engine axis). This dimensional change allows the hinge pin to clear the aerodynamic flow surface without requiring a bump out, while still enabling proper blocker door pivoting through spherical or gimbal joint mechanisms that accommodate the offset positioning.
2Shape
If the hinge pin is misaligned with the hinge line to eliminate bump outs, then the aerodynamic flow surface shape is maintained, but the hinge mechanism becomes more complex requiring spherical joints or gimbal mechanisms
Solution Approach 1:
The patent introduces spherical joints or gimbal mechanisms as intermediary components between the misaligned hinge pin and the blocker door. These intermediaries accommodate the angular misalignment while transmitting the necessary rotational motion, effectively mediating between the simplified aerodynamic surface and the required door pivoting function.
3Reliability
If a bump out or blister fairing is added to accommodate the hinge pin alignment, then the hinge mechanism is simple and robust, but the packaging efficiency is reduced and aesthetics are compromised
Solution Approach 1:
The patent extracts the hinge pin from its traditional position within the aerodynamic flow surface and relocates it to an offset position where it does not interfere with the smooth surface. This extraction eliminates the need for space-consuming bump outs or blister fairings, improving packaging efficiency while maintaining hinge mechanism functionality through the offset spherical or gimbal joint design.
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 enhances aerodynamic performance by maintaining the ideal flow surface shape and reduces the impact on engine performance and aesthetics.
Implementation Method 1
The use of a spherical bearing at the blocker door hinge allows the hinge pin to be misaligned with the hinge line, enabling the hinge pin to fit within the ideal aerodynamic flow surface
Data Source
AI summary
An aircraft propulsion system includes an engine assembly including a fan that rotates to move air to create thrust, and a cowl that surrounds at least a portion of the engine assembly. The cowl includes an outer surface arranged away from the engine assembly that provides an aerodynamic surface. The aircraft propulsion system also includes a thrust reverser mechanism connected to the cowl and configured to change a direction of the thrust while in a reverse position. The thrust reverser includes a blocking door and blocking door hinge. The blocking door is connected to the blocking door hinge, and the blocking door is configured to pivot around a hinge line between a forward position and the reverse position. The blocking door hinge includes a hinge bolt that is misaligned with the hinge line.