Aircraft Engine Fan Cowl Cradle Mounting for Drag Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing aircraft engine assembly experiences misalignment and drag issues due to engine deformation during stress conditions, such as take-off and turbulence, caused by the fixed cradle of the forward aerodynamic structure being secured to the rigid structure, leading to geometry modifications and loss of flush junctions between the nacelle air intake and fan cowls.
Innovation Solution
The cradle of the forward aerodynamic structure is equipped with both aft and forward mounting means, with the aft mounting means attached to the rigid structure and the forward mounting means attached to the fan case, allowing for better engine deformation accommodation and maintaining flush junctions between the nacelle air intake and fan cowls, reducing drag losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cradle of the forward aerodynamic structure is fixedly mounted on the rigid structure, then the structural support for fan cowls is ensured, but misalignment occurs between the nacelle air intake and fan cowls during engine deformation, causing increased drag
Solution Approach 1:
The cradle is transformed from a fixed rigid mounting to a dynamic system with two separate mounting elements (forward mounting means on the fan case and aft mounting means on the rigid structure) that allow relative movement. This enables the cradle to adapt its position during engine deformation while maintaining aerodynamic alignment, thus reducing drag while preserving structural support capability.
2Shape
If the cradle is mounted solely on the fan case, then the forward position is maintained, but the aerodynamic cowling no longer lies flush with the fairing, causing misalignment and drag
Solution Approach 1:
The aft mounting means acts as an intermediary between the cradle and the rigid structure, providing a reference point that maintains the correct aerodynamic alignment. By distributing mounting points across both the fan case (forward) and rigid structure (aft), the system maintains proper geometric relationships during deformation, ensuring the aerodynamic cowling remains flush with the fairing.
3Force
If the cradle is secured to the rigid structure, then load transmission is ensured, but the geometry of the assembly is substantially modified during stress conditions, leading to misalignment
Solution Approach 1:
The single rigid mounting connection is segmented into two separate mounting elements: forward mounting means connected to the fan case and aft mounting means connected to the rigid structure. This segmentation allows each mounting point to independently accommodate deformation while maintaining overall load transmission capability and geometric stability of the assembly.
Data Source
AI summary
An aircraft engine assembly including an engine, an engine mounting structure, and a nacelle surrounding the engine and including fan cowls. The mounting structure includes a rigid structure and a forward aerodynamic structure on which the fan cowls are hinged, the forward aerodynamic structure including a cradle provided with an aft mounting mechanism mounted on the rigid structure. The cradle also includes a forward mounting mechanism mounted on a fan case of the engine.