Unducted Fan Propulsor Placement for Lower-Drag Aircraft Thrust
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Solution Overview
Problem
The installation of unducted fan propulsors on aircraft results in increased drag and weight penalties, necessitating higher engine power and fuel flow, which traditional mounting locations fail to address effectively.
Innovation Solution
Positioning the unducted fan propulsor relative to the aircraft's effective quarter chord point (QC) and fan blade size to offset interference and scrubbing effects, utilizing high-pressure air flow from the wing to enhance thrust without increasing power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the unducted fan propulsor is installed on the aircraft wing, then thrust is generated to propel the aircraft, but drag and weight penalties increase
Solution Approach 1:
The patent applies local quality by positioning the propulsor at specific locations on the wing (inboard or outboard of the quarter-chord point) where the wing's pressure distribution is most favorable. This localized positioning optimizes the interaction between the propulsor and the wing's high-pressure region, maximizing thrust generation while minimizing drag penalties associated with the installation.
Solution Approach 2:
The patent converts the harmful interference and scrubbing effects that traditionally occur with wing-mounted propulsors into beneficial effects. By strategically positioning the propulsor to utilize the wing's high-pressure air flow, the design transforms what would normally be detrimental interference into a useful resource that enhances thrust without requiring additional engine power.
2Power
If the unducted fan propulsor size increases, then more thrust is generated, but weight and installation penalties increase
Solution Approach 1:
The patent changes the critical parameter of propulsor positioning relative to the wing's quarter-chord point to optimize performance. By adjusting this positional parameter, the system achieves enhanced thrust generation from the same propulsor size, effectively decoupling the thrust output from the propulsor weight and reducing the need for larger, heavier units.
3Ease of manufacture
If traditional mounting locations are used for the propulsor, then installation is straightforward, but interference and scrubbing effects increase drag
Solution Approach 1:
The patent identifies specific local regions on the wing (inboard or outboard of the quarter-chord point) that provide optimal aerodynamic conditions. By targeting these specific locations, the design achieves reduced interference and scrubbing effects while maintaining practical installation considerations, balancing ease of manufacture with performance optimization.
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 positioning strategy reduces drag and noise interference, improving aircraft performance and fuel efficiency by optimizing the propulsor's location to harness wing-induced pressure without increasing engine power.
Implementation Method 1
utilizing high-pressure air flow from the wing to enhance thrust without increasing power requirements
Implementation Method 2
Positioning the unducted fan propulsor relative to the aircraft's effective quarter chord point (QC) and fan blade size to offset interference and scrubbing effects
Data Source
AI summary
The present disclosure is generally related to aircraft having one or more unducted fan propulsors at locations within specific regions relative to an airfoil, such as a wing or horizontal stabilizer. More specifically, the specific regions are located where there is a relatively higher pressure air flow beneath the wings or above a horizontal stabilizer. That higher pressure air flow can be utilized to provide increased thrust from the unducted fan propulsor.