Pusher Propeller Noise Reduction via Boundary Layer Suction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pusher propeller-driven aircraft generate significant noise due to wake encounters with upstream aerodynamic surfaces, making them more detectable and posing a challenge in stealth operations, as existing noise reduction methods for tractor propellers do not effectively address wake formation and resulting noise emissions.
Innovation Solution
The implementation of an airfoil-shaped flight surface with a scoop to route boundary layer air and a suction device to apply a suction force through a slot or opening, minimizing wake development and propeller noise, while allowing the aircraft to maintain the advantages of its pusher propeller configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pusher propeller configuration is used, then the aircraft can achieve certain operational advantages, but significant noise is generated due to wake encounters with upstream aerodynamic surfaces
Solution Approach 1:
The invention extracts the boundary layer air from the upstream aerodynamic surfaces using scoops and suction devices, removing the source of wake formation before it can encounter the propeller. This separates the harmful wake generation from the propeller noise problem, allowing the pusher configuration to retain its operational advantages while eliminating the noise issue.
Solution Approach 2:
The invention introduces scoops and suction devices as intermediary elements between the upstream aerodynamic surfaces and the propeller. These intermediaries capture and remove boundary layer air, preventing direct interaction between the wake and propeller blades, thus reducing noise while maintaining the pusher configuration.
2Object-generated harmful factors
If existing noise reduction methods for tractor propellers are applied, then some noise reduction may be achieved, but they do not effectively address wake formation and resulting noise emissions in pusher configurations
Solution Approach 1:
The invention applies noise reduction measures specifically localized to the pusher propeller configuration by placing scoops and suction devices on upstream aerodynamic surfaces. This local approach addresses the specific wake formation problem in pusher configurations rather than applying generic tractor propeller noise reduction methods, achieving effective noise reduction where it is most needed.
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 solution significantly reduces propeller noise to levels comparable to traditional tractor propellers, enhancing the stealth capabilities of pusher propeller aircraft by minimizing wake formation and noise emissions, thereby reducing the risk of detection during missions.
Implementation Method 1
a suction device enabled to provide a suction force (preferably, pressure) wherein said scoop routes boundary layer air from said flight surface to said suction device
Implementation Method 2
routing boundary layer air from an airfoil-shaped flight surface
Data Source
AI summary
A system and method for reducing the noise penalty of a pusher propeller, allowing an aircraft to retain its advantages for UAV configurations, while allowing acoustic performance similar to that of a tractor propeller by reducing, or eliminating, propeller noise emissions. The system and method provide an airfoil-shaped flight surface with (i) a scoop configured to route boundary layer air and associated wake from said flight surface, and (ii) a suction device configured to provide a suction pressure, wherein the scoop routes boundary layer air from the flight surface to the suction device via an opening in the flight surface.