Tiltrotor Rotor Position Control via Aerodynamic Drag
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional systems for controlling rotor position in tiltrotor aircraft are heavy and require extensive maintenance, adding to the overall weight and complexity of the aircraft while not efficiently managing aerodynamic drag during non-use modes.
Innovation Solution
The implementation of a rotor position control system utilizing off-axis tilting gearboxes and electric motors, allowing rotors to be actively moved to low aerodynamic drag positions using a phase lock mechanism, which reduces weight and maintenance needs by minimizing download in hover mode and optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical components are used for rotor position control, then rotor positioning is achieved, but aircraft weight increases and maintenance requirements increase
Solution Approach 1:
The patent replaces complex mechanical position control components with an aerodynamic solution where rotor blade orientation itself creates drag-based positioning force. The rotor blades are oriented at specific angles (e.g., 45 degrees) relative to the rotor axis, allowing aerodynamic drag to naturally position and hold the rotor in desired positions without heavy mechanical actuators or sensors.
Solution Approach 2:
The system uses the rotor blades' own aerodynamic interaction with the air flow to achieve self-positioning and self-holding. The asymmetric drag forces generated by blades at specific orientations automatically create restoring forces that maintain rotor position, eliminating the need for external mechanical positioning systems.
2Reliability
If conventional mechanical components are used for rotor position control, then rotor positioning is achieved, but maintenance requirements increase
Solution Approach 1:
By replacing mechanical positioning mechanisms with aerodynamic drag-based positioning, the patent eliminates moving parts, bearings, gears, and sensors that would require maintenance. The positioning function is achieved through the natural aerodynamic interaction between rotor blades and air flow, requiring no active maintenance.
Solution Approach 2:
The aerodynamic positioning system is self-regulating and requires no maintenance intervention. The rotor blades automatically find and maintain their optimal orientations through aerodynamic forces, with no mechanical components to wear, fail, or require adjustment.
3Device complexity
If rotors are not actively positioned in low drag configurations, then simpler control systems are used, but aerodynamic drag increases during non-use modes
Solution Approach 1:
The patent makes the rotor blade orientation dynamic and adjustable, allowing blades to be positioned at optimal angles (e.g., 45 degrees) during non-use modes to minimize drag. This dynamic reconfiguration capability allows the system to adapt to different operational states, reducing energy loss when rotors are not providing thrust.
Solution Approach 2:
The system changes the orientation parameter of rotor blades relative to the rotor axis, positioning them at specific angles that minimize aerodynamic drag during non-use modes. This parameter adjustment transforms the rotors from potential drag sources into aerodynamically efficient configurations.
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 reduces the weight and maintenance requirements of tiltrotor aircraft while improving propulsive efficiency by minimizing download in hover mode and optimizing power usage, allowing for efficient thrust generation and reduced drag during non-use modes.
Implementation Method 1
The implementation of a rotor position control system utilizing off-axis tilting gearboxes and electric motors
Implementation Method 2
cogging torque level resistance... sufficient to return the rotor to an indexed position
Data Source
AI summary
An tiltrotor aircraft includes a rotor position control system (RPCS). The RPCS includes an electric motor configured to selectively rotate the rotor blade, a target marker kinematically associated with the rotor blade, a sensor configured to sense a position of the target marker, and a flight control computer configured to selectively control the electric motor in a normal mode of operation in which the rotor blade provides thrust and a phase lock mode of operation in which the electric motor maintains the rotor blade in a predetermined indexed position.