Aircraft Nacelle Rear Frame Asymmetric Offset Weight Reduction
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Solution Overview
Problem
Aircraft nacelles face challenges in reducing on-board weight due to the weight of moving elements like cowls and stationary panels, which are rigid and reinforced for aerodynamic forces, leading to increased structural weight.
Innovation Solution
The rear frame of the nacelle is offset over more than 50% of its periphery relative to the front frame, allowing for reduced dimensions of moving elements and increased dimensions of stationary panels, made of composite materials, to absorb forces and reduce weight, with strategically placed openings for access and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If moving elements like cowls and stationary panels are made rigid and reinforced to withstand aerodynamic forces, then structural strength is improved, but on-board weight increases
Solution Approach 1:
The rear frame is designed with an asymmetric configuration where point B is offset toward the rear of the nacelle relative to point A over more than 50% of the periphery. This asymmetric positioning allows for optimized distribution of structural elements, enabling reduced dimensions of moving elements while maintaining structural integrity through strategic placement of reinforced stationary panels.
2Weight of moving object
If the rear frame is offset over more than 50% of its periphery, then weight is reduced by minimizing moving elements, but structural integrity must be maintained
Solution Approach 1:
The invention applies local quality by making stationary panels made of composite materials to absorb forces at critical locations. The asymmetric offset of the rear frame allows for concentrated reinforcement at specific points where structural loads are highest, rather than uniformly reinforcing the entire structure, thus reducing overall weight while maintaining integrity.
3Weight of moving object
If stationary panels are made of composite materials, then weight is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention specifies that stationary panels are made of composite materials to absorb aerodynamic forces. This material choice reduces the weight of these panels compared to traditional metal constructions. The composite materials provide high strength-to-weight ratio, allowing for reduced panel dimensions while maintaining the ability to withstand structural loads.
Data Source
AI summary
An aircraft nacelle includes a lip whose surface contacts with the aerodynamic streams extends inside the nacelle by an inside wall that delimits a layer that empties at a power plant and outside of the nacelle by an outside wall, a first front frame connects the inside and outside walls, delimiting an annular pipe with the lip, and a rear frame connects the inside and outside walls at a junction zone between the inside pipe and power plant pipe, for a given cross-section of the nacelle along a plane that contains the longitudinal axis of the nacelle, a point A at the intersection between the rear frame and the inside wall, and a point B at the intersection between the rear frame and the outside wall, with B being offset toward the rear of the nacelle relative to A over more than 50% of the rear frame's periphery.