Plate Member for Rotor Shaft Fairing Drag Reduction
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Solution Overview
Problem
Conventional rotary-wing aircraft face limitations in forward airspeed due to drag created by various surfaces, which affects power requirements and efficiency, necessitating an improvement in the airlift-to-drag ratio.
Innovation Solution
A plate member is mounted to the rotor shaft fairing to increase its aspect ratio and reduce induced drag, comprising multiple surface portions and an active air discharge system to disrupt the airstream, thereby minimizing rotor hub wake size and drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional rotor shaft fairing design is used, then the structure is simple, but drag is high and airlift-to-drag ratio is reduced
Solution Approach 1:
The patent applies dimensionality change by adding a plate member that extends in the spanwise direction (lateral dimension) from the rotor shaft fairing. This increases the aspect ratio of the fairing by projecting plates outward from the sides, effectively adding dimensional extent to reduce induced drag without fundamentally redesigning the entire fairing structure.
Solution Approach 2:
The fairing is segmented into multiple components: the base rotor shaft fairing and separate plate members that can be independently mounted. This segmentation allows the drag-reducing plates to be added as modular elements rather than requiring a complete fairing redesign, balancing complexity reduction with performance improvement.
2Speed
If forward airspeed is increased, then operational capability is improved, but drag increases and power requirements increase
Solution Approach 1:
The patent changes the geometric parameters of the fairing by adding plate members that increase the aspect ratio. This parameter modification reduces induced drag coefficients, allowing the aircraft to maintain lower drag levels at higher forward airspeeds, thereby improving operational capability without proportional increases in power requirements.
3Loss of energy
If plate member is added to increase aspect ratio, then induced drag is reduced, but device complexity and weight increase
Solution Approach 1:
The plate members are designed with mounting mechanisms that allow for potential adjustment or removal, introducing dynamic flexibility to the fairing configuration. This enables optimization of the aspect ratio based on operational requirements while maintaining the ability to modify the structure if 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
The solution effectively reduces drag on the rotor shaft fairing, enhancing the operational envelope of rotary-wing aircraft by increasing the airlift-to-drag ratio and improving efficiency.
Implementation Method 1
The plate member is configured and disposed to increase an aspect ratio of and reduce induced drag on the rotor shaft fairing
Implementation Method 2
an active air generation system mounted in one of the fuselage and the rotor assembly. The active air generation system is configured and disposed to generate and direct a flow of air out through the active air discharge opening to disrupt an airstream flowing over the outer surface of the rotor shaft fairing
Data Source
AI summary
A rotary wing aircraft includes a fuselage having a plurality of surfaces, at least one engine mounted in the fuselage, and a rotor assembly including a rotor shaft and plurality of rotor blades operatively connected to the rotor shaft. The rotor assembly includes a plurality of surface portions. A rotor shaft fairing extends between the fuselage and the rotor assembly and about at least a portion of the rotor shaft. The rotor shaft fairing includes an outer surface. A plate member is mounted to and projects proudly of the at least a portion of the rotor shaft fairing. The plate member is configured and disposed to increase an aspect ratio of and reduce induced drag on the rotor shaft fairing as well as reduce rotor hub wake size.