Pivoting Sail Fairing for Rotary Wing Aircraft Drag Reduction
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Solution Overview
Problem
The existing static sail fairings on dual, counter-rotating, coaxial rotor systems of rotary wing aircraft are ineffective in reducing drag when the relative airflow is not head-on, as they do not adapt to changing wind angles, leading to increased drag and interference effects.
Innovation Solution
A pivotable sail fairing system that rotates about a hub shaft, equipped with actuators and bearings, allowing it to adjust its position based on sensor readings to maintain optimal alignment with the airflow, reducing drag by minimizing interference and optimizing surface profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a static sail fairing is used on a dual counter-rotating coaxial rotor system, then the structure is simple and easy to manufacture, but the aerodynamic drag increases when the relative airflow is not head-on because the fairing cannot adapt to changing wind angles
Solution Approach 1:
The sail fairing is transformed from a static structure to a dynamic one by enabling it to pivot about the hub shaft. The pivotable fairing can rotate to different angles relative to the airflow direction, allowing it to adapt to varying wind conditions and maintain optimal aerodynamic performance across a wider range of operating conditions.
Solution Approach 2:
The fairing's orientation parameter is made variable through the pivot mechanism. By changing the angular parameter of the fairing relative to the airflow, the system optimizes aerodynamic performance for different wind angles, reducing drag that would otherwise occur with a fixed-orientation fairing.
2Object-affected harmful factors
If a pivotable sail fairing system with actuators and sensors is implemented, then the aerodynamic drag is reduced across a wider range of wind angles, but the device complexity increases
Solution Approach 1:
A sensor is implemented to detect the angle of attack or airflow direction, and this information is fed back to the actuator control system. The actuator then adjusts the fairing's pivot angle based on this feedback, creating a closed-loop control system that automatically optimizes aerodynamic performance without requiring complex manual intervention.
Solution Approach 2:
The fairing system is designed to self-adjust to optimal angles using the sensor-actuator loop. The system serves itself by automatically detecting airflow conditions and repositioning the fairing accordingly, reducing the need for external control and minimizing the complexity of the overall control architecture.
3Productivity
If the sail fairing is made pivotable about the hub shaft, then the interference effects are minimized and aerodynamic efficiency is improved, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
The fairing structure is segmented into a modular design that allows the pivot mechanism to be integrated as a separate functional unit. This segmentation enables independent optimization of the pivot mechanism and the fairing surfaces, simplifying manufacturing and assembly while maintaining aerodynamic efficiency.
Solution Approach 2:
A pivot mechanism acts as an intermediary between the static hub structure and the aerodynamic fairing surfaces. This intermediary component enables the fairing to rotate independently, minimizing interference effects between the rotor system and the fairing while maintaining structural integrity and manufacturability.
Data Source
AI summary
According to an aspect, a pivoting sail fairing system includes a rotatable fairing, for rotation about a first axis of rotation of an aircraft, that includes a housing that defines a compartment arranged inward from the housing, the housing including a first orifice on a first surface and a second orifice on a second surface of the housing, and a first actuator mounted on a surface of the compartment inward from the housing.