Isostatic Aircraft Strut Attachment Reducing Aerodynamic Losses
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Solution Overview
Problem
Aircraft attachment struts for turbomachines cause significant aerodynamic losses due to their bulk, which affects the overall performance and efficiency of aircraft.
Innovation Solution
The design of an isostatic attachment system with strategically offset attachments and a connecting rod, allowing for efficient reaction of forces and reduced strut bulk, minimizing disruptions to the secondary flow in dual-flow turbomachines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the attachment strut is designed with conventional bulk to ensure structural strength and force reaction, then the structural strength and reliability are improved, but the aerodynamic losses increase and the overall performance of the aircraft deteriorates
Solution Approach 1:
The attachment system is segmented into multiple discrete attachments (first attachment, second attachment, third attachment, and fourth attachment with connecting rod) distributed at different positions and orientations. This segmentation allows each component to be optimized for specific force reactions while minimizing the overall bulk of the attachment strut, thereby reducing aerodynamic losses while maintaining structural strength.
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement of attachments, offsetting them in vertical and transverse directions relative to each other. The fourth attachment includes a connecting rod extending backward with vertical offset, creating a three-dimensional force reaction system. This dimensional arrangement enables efficient force distribution without requiring a bulky strut structure, reducing aerodynamic interference.
2Force
If the attachment means are spaced apart in transverse direction to increase lever arm for force reaction, then the force reaction efficiency is improved, but the transverse bulk of the strut increases causing more aerodynamic disruptions
Solution Approach 1:
Instead of spacing attachments only in the transverse direction, the patent offsets attachments in the vertical direction as well. The fourth attachment is vertically offset from the first attachment, and the connecting rod extends backward with vertical offset. This vertical dimensionality allows for increased lever arm and force reaction efficiency without proportionally increasing the transverse bulk, thereby minimizing aerodynamic disruptions.
Solution Approach 2:
The attachments are arranged asymmetrically in terms of their vertical and transverse offsets rather than symmetrically spaced apart. The fourth attachment with its connecting rod creating a vertical offset breaks the symmetry, allowing for optimized force reaction moments while minimizing the transverse envelope of the attachment system, thus reducing aerodynamic interference.
3Loss of energy
If the primary structure of the strut is made to cross through the secondary annular channel to reduce bulk, then the aerodynamic losses are reduced, but the disruption to the secondary flow increases
Solution Approach 1:
The force reaction function is segmented across multiple attachments distributed in space rather than concentrated in a single bulky strut structure. This allows the primary structure to be minimized or eliminated in the secondary flow path, reducing aerodynamic losses while the distributed attachments maintain structural integrity and force reaction capabilities.
Solution Approach 2:
The distributed attachment system acts as an intermediary that provides structural support and force reaction without requiring a continuous bulky strut structure through the secondary flow path. The attachments serve as discrete intermediaries that transfer loads while minimizing interference with the secondary flow, thereby reducing both aerodynamic losses and flow disruption.
Data Source
AI summary
An assembly for an aircraft including: a mechanism attaching a primary structure of an attachment strut to a wing, forming an isostatic system; an attachment housed in a leading edge of the wing and configured to only take up forces exerted along the transverse and longitudinal directions; and an attachment including a connecting rod extending rearwardly, of which one end is connected to the primary structure and the other end is connected to the wing element, the connecting rod being offset along the vertical direction of the attachment.