Adaptable Rotor Control System for Multi-Blade Tiltrotors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotor systems struggle to achieve optimal delta-3 pitch-flap coupling for tiltrotor aircraft with more than three blades, as the location of pitch horns interferes with neighboring blades, making it challenging to maintain stability during high-speed flight.
Innovation Solution
A rotor control system with a yoke, constant velocity joint, swashplate, and adaptive pitch links that allow for the adjustment of rotor blade pitch and phase, enabling the use of more than three blades while maintaining optimal delta-3 coupling, achieved through a combination of lower and upper pitch links and phase adjustment levers that adapt the control phase to accommodate varying numbers of blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of rotor blades is increased to improve lift and reduce blade spacing, then the rotor complexity increases and pitch horn location interferes with neighboring blades
Solution Approach 1:
The pitch control system is segmented into multiple independent pitch links, each capable of being individually positioned. This allows the pitch links to be distributed around the rotor hub, enabling support for more blades without increasing overall system complexity. Each pitch link operates independently to control its corresponding blade's pitch angle.
Solution Approach 2:
The pitch link assembly is designed as a universal component that can be configured to work with different numbers of blades. The same basic pitch link structure can be positioned at different locations around the hub to accommodate 3, 4, 5, or more blades, making the system multi-functional and adaptable to various rotor configurations.
2Reliability
If pitch horns are repositioned to achieve optimal delta-3 coupling, then blade control performance improves, but pitch horns interfere with neighboring blades
Solution Approach 1:
The pitch links are positioned in a three-dimensional space around the rotor hub, utilizing vertical and radial dimensions in addition to the circumferential position. This spatial distribution allows optimal delta-3 coupling to be achieved while maintaining sufficient clearance from neighboring blades, as the pitch links can be positioned at different radii and heights rather than being constrained to a single plane.
Solution Approach 2:
The pitch link serves as an intermediary component between the blade root and the pitch control mechanism. By introducing this intermediate element, the system can achieve the required delta-3 coupling geometry without the pitch horn directly interfering with the blade passage, as the pitch link transmits the control motion through an intermediate position.
3Quantity of substance
If conventional rotor systems are used with more than three blades, then blade spacing decreases, but optimal delta-3 coupling cannot be achieved
Solution Approach 1:
The pitch link system is designed with dynamic positioning capability, allowing the pitch links to be independently adjusted to optimal positions for each blade. This dynamic configurability ensures that even with decreased blade spacing, each pitch link can be precisely positioned to achieve the required delta-3 coupling angle, maintaining manufacturing precision regardless of the number of blades.
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 allows for increased flexibility in the number of rotor blades, supporting up to 20 or more blades, while maintaining stability by achieving both pitch-flap and pitch-cone coupling, thus addressing the limitations of conventional systems in achieving optimal delta-3 coupling for tiltrotor aircraft.
Implementation Method 1
a constant velocity joint to drive torque from a mast to the yoke and to enable the yoke to pivot
Implementation Method 2
a plurality of phase adjustment levers configured to adjust a control phase associated with motion transferred between the plurality of actuators and the plurality of lower pitch links
Implementation Method 3
a plurality of upper pitch links configured to adjust a pitch of the plurality of rotor blades
Data Source
AI summary
In one embodiment, a rotor hub comprises a yoke for attaching a plurality of rotor blades, a constant velocity joint to drive torque from a mast to the yoke and to enable the yoke to pivot, and a rotor control system configured to adjust an orientation of the plurality of rotor blades. Moreover, the rotor control system comprises: a swashplate, a phase adapter fulcrum, a plurality of actuators controlled based on a flight control input, a plurality of lower pitch links configured to transfer motion between the plurality of actuators and the swashplate, a plurality of phase adjustment levers configured to adjust a control phase associated with motion transferred between the plurality of actuators and the plurality of lower pitch links, and a plurality of upper pitch links configured to adjust a pitch of the plurality of rotor blades, wherein there are more upper pitch links than lower pitch links.