Overwing Engine Struts for Low-Clearance Aircraft Design
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Solution Overview
Problem
Low wing aircraft designs face challenges with limited vertical clearance due to engine positioning, leading to increased drag and impact on aircraft architecture, especially with open rotor engines requiring shielding and affecting performance.
Innovation Solution
The engines are mounted to struts that position them over the wings, maintaining a conventional strut architecture and avoiding structures on the top side of the wings, allowing for various engine types and improved thermal and safety conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If engines are positioned under the wing in a low wing aircraft, then the aircraft maintains a conventional low wing design, but the vertical clearance between the engines and the ground becomes limited
Solution Approach 1:
The patent positions the engines in a third dimension by mounting them over the wing rather than under it, using struts that extend upward from the wing top surface. This dimensional change allows the engines to be elevated above the wing while maintaining the low wing configuration, thereby increasing vertical clearance without altering the fundamental low wing design.
2Length of moving object
If the engines are raised to increase vertical clearance, then the clearance improves, but larger overwing fairings are required which increase drag and reduce aircraft performance
Solution Approach 1:
The patent extracts the engines from the conventional underwing position and relocates them to an overwing position using struts. This extraction eliminates the need for large overwing fairings that would be required to accommodate raised engines, thereby reducing drag and energy loss while maintaining improved vertical clearance.
3Length of moving object
If the gear height is increased to address low clearance, then the clearance improves, but significant impacts are made to the aircraft architecture, wing planform, and potential tail size
Solution Approach 1:
The patent segments the engine mounting function from the wing structure itself by introducing separate strut assemblies. This segmentation allows the engines to be positioned above the wing without requiring changes to the wing planform, aircraft architecture, or tail size, as the struts provide independent support and positioning.
4Ease of operation
If turbofan engines are mounted under the wing, then the engines are positioned conveniently, but the exhaust is directed under the wing requiring shielding that increases weight and complexity
Solution Approach 1:
The patent inverts the conventional engine mounting arrangement by positioning the engines over the wing instead of under it. This inversion causes the exhaust to be directed away from the wing, eliminating the need for shielding structures and reducing both weight and device complexity while maintaining ease of engine mounting and maintenance.
Data Source
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AI summary
An aircraft that includes a fuselage, right and left wings coupled to the fuselage, struts that are connected to and that extend outward from an underside of the wings, and engines mounted to the struts. The struts are configured to locate the engines in an overwing position. (Fig. 1)