Active Blade Tip Gap Control for Ducted Proprotors
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Solution Overview
Problem
Ducted rotor systems face challenges in monitoring and controlling the changing tip gap between rotor blades and the duct, leading to performance degradation and risk of collisions, as current systems are unable to actively or semi-actively manage this gap effectively.
Innovation Solution
A tip gap control system that includes a flight control computer with a blade length control module generating actuator commands for active blade tips, allowing them to be retracted or extended to adjust the tip gap, coupled with sensors to monitor and adjust the gap based on flight conditions and structural deformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor blades are shortened to prevent collisions with the duct, then the risk of collision is reduced, but the thrust production efficiency deteriorates
Solution Approach 1:
The blade tips are made dynamically adjustable through active actuators that can extend or retract the blade length in real-time. This allows the system to adapt the blade geometry based on flight conditions, transitioning from a static to a dynamic configuration that optimizes both safety and performance.
Solution Approach 2:
The physical parameter of blade length is changed dynamically through actuator control. By adjusting the blade tip position, the system modifies the effective blade length parameter to prevent collisions during high-load maneuvers while maintaining optimal length for thrust production during normal operation.
2Productivity
If the tip gap is reduced to maximize duct performance, then the thrust efficiency is improved, but the risk of blade-duct collision increases
Solution Approach 1:
The system incorporates sensors that continuously monitor the tip gap distance and provide feedback to the control system. This feedback loop enables real-time detection of gap reduction and triggers actuator response to extend the blade tips, maintaining a safe gap while preserving optimal performance settings.
Solution Approach 2:
The control system takes preliminary action by detecting potential collision risks before actual contact occurs. The sensors monitor gap changes and trigger actuator extension in advance, preventing collisions before they happen rather than reacting after damage occurs.
3Adaptability or versatility
If the blade tips are made active with extendable mechanisms, then the tip gap control capability is improved, but the device complexity increases
Solution Approach 1:
The blade tip is segmented into a fixed main body and a movable extension portion. This segmentation allows the control system to adjust only the tip portion independently, achieving tip gap control without requiring the entire blade to be complex or movable.
Solution Approach 2:
The active control capability is extracted and concentrated specifically at the blade tips rather than being distributed throughout the entire blade structure. This localization of complexity to only the necessary region minimizes overall system complexity while achieving the desired adaptability.
4Productivity
If the rotor blades are made longer to improve thrust production, then the efficiency is improved, but the likelihood of collisions with the duct increases
Solution Approach 1:
The blade length is transformed from a static design parameter to a dynamic variable that can be adjusted in real-time. This allows the system to utilize longer blades for improved thrust production during normal operation while dynamically shortening them during maneuvers that would cause collisions.
Data Source
AI summary
A tip gap control system for a ducted aircraft includes a flight control computer including a blade length control module configured to generate a blade tip actuator command and a proprotor system in data communication with the flight control computer. The proprotor system includes a duct and proprotor blades surrounded by the duct. Each of the proprotor blades includes an active blade tip movable into various positions including a retracted position and an extended position. The tip gap control system also includes one or more actuators coupled to the active blade tips. The one or more actuators move the active blade tips between the various positions based on the blade tip actuator command, thereby controlling a tip gap between the proprotor blades and the duct.