Underwing Pylon Mounting Assembly for Torque-Safe Wing Removal
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Solution Overview
Problem
The removal of underwing pylons from aircraft wings often causes damage to the primary wing structure due to excessive unscrewing torque, leading to costly repairs and potential compromise of the support system.
Innovation Solution
An anti-rotation configuration is implemented that transfers torsional stresses from the wing to the pylon during disassembly, using a combination of first and second annular anti-rotation elements to redirect unscrewing torque away from the wing's aluminum alloy structure, thereby preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the threaded pin is unscrewed using excessive torque to remove the underwing pylon, then the pylon can be removed, but damage occurs to the aluminum alloy rib structure of the wing
Solution Approach 1:
A steel protective sleeve is introduced as an intermediary component between the aluminum alloy rib and the threaded pin. The sleeve has a conical outer surface that interfaces with the rib and a threaded inner hole that receives the pin. This intermediary steel component absorbs the torsional stresses during unscrewing, preventing direct transmission of damaging forces to the aluminum rib structure while still enabling pylon removal.
Solution Approach 2:
The material parameter of the protective interface is changed from aluminum alloy (rib) to steel (sleeve). Steel has higher torsional strength and durability, allowing it to withstand the repeated unscrewing operations without damage. This parameter change enables the system to tolerate the necessary unscrewing torques without compromising the wing structure.
2Adaptability or versatility
If the same underwing pylon mounting location is reused after repair, then the pylon can be remounted, but the support system may be compromised due to repeated damage
Solution Approach 1:
The steel protective sleeve is installed in advance on the aluminum rib before any pylon mounting or removal operations. This preliminary protective measure ensures that the rib is pre-protected against potential damage from future unscrewing operations, allowing repeated pylon remounting without compromising the rib's structural integrity or the support system's reliability.
3Ease of operation
If the conical bushing and top nut rotate together with the threaded retaining element during unscrewing, then the pylon can be removed, but damage results to the seat made in the rib
Solution Approach 1:
The steel protective sleeve acts as a mediator that prevents the conical bushing and top nut from rotating directly against the aluminum rib seat. The sleeve's robust steel construction absorbs the rotational stresses, preventing damage to the precision-machined seat in the rib while still allowing the necessary rotation for pylon disassembly.
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 solution effectively prevents damage to the wing's structure during pylon disassembly by deflecting torsional stresses onto the steel pylon, ensuring easier and safer removal without compromising the wing's mechanical integrity.
Implementation Method 1
an anti-rotation device (30) that transfers torsional stresses, which may occur while disassembling the underwing pylon (11), to said pylon (11) and not to the structure of the wing
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An assembly for removably mounting an underwing pylon (11) to a rib (10) of an aircraft wing is described. The assembly comprises a prismatic body (12) insertable into a prismatic cavity (22) of the pylon, a threaded retaining element (14) having an upwardly tapered outer conical surface (15), and a vertical threaded pin (13) inserted through a vertical through hole (12e) of the prismatic body (12). The assembly further comprises an anti-rotation device (31, 32) for rotationally locking the threaded retaining element (14) to the prismatic body (12) relative to a vertical axis (A).