Compact Blade Pitch Mechanism With Fail-Safe Low-Drag Positioning
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Solution Overview
Problem
Existing blade pitch control mechanisms in aircraft are not compact, redundant, and reliable, particularly in vertical take-off and landing (VTOL) aircraft, where precise thrust distribution and blade pitch angle control are crucial for hover and forward flight operations.
Innovation Solution
A compact propeller blade pitch control mechanism using a pitch plate coupled to blade roots via kinematic links, actuated by a power screw, allowing simultaneous adjustment of blade pitch angles, with redundant gas springs to maintain low drag in failure scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact blade pitch control mechanism is used, then the device size is reduced, but the reliability and redundancy may be compromised
Solution Approach 1:
The patent merges multiple functions into a single integrated pitch control mechanism. The power screw actuator simultaneously controls the pitch of all propeller blades through a common pitch plate, reducing the number of separate components while maintaining control reliability through the unified design.
Solution Approach 2:
The patent incorporates redundant gas springs that can maintain the blade pitch in a safe position in the event of power screw failure. This beforehand cushioning ensures reliability is maintained even if the primary actuator fails, addressing the reliability concern while keeping the mechanism compact.
2Measurement precision
If simultaneous blade pitch control is achieved, then the control precision is improved, but the mechanism complexity increases
Solution Approach 1:
The pitch plate serves as a universal component that simultaneously controls the pitch of all propeller blades. By using a single power screw actuator to move the common pitch plate, the mechanism achieves simultaneous control of all blades with minimal complexity, as one component performs the function of coordinating multiple blade pitches.
Solution Approach 2:
The pitch plate acts as an intermediary component between the power screw actuator and the individual blade pitch control linkages. This mediator translates the single linear motion of the power screw into coordinated rotational motion for all blades, achieving precise simultaneous control while keeping the overall mechanism simple through this intermediate element.
3Reliability
If a power screw actuator is used, then the control reliability is improved, but the device complexity and size increase
Solution Approach 1:
The power screw actuator is integrated directly with the pitch plate and hub assembly, merging the actuator function with the existing structural components. This integration reduces the need for separate mounting structures and complex linkages, maintaining reliability while minimizing the added complexity and size.
Solution Approach 2:
The power screw actuator operates in the axial dimension, moving the pitch plate along the propeller spin axis. This linear axial motion is then converted to rotational pitch control through the kinematic links, utilizing a different dimension (rotation) to achieve the final control function, thereby simplifying the overall actuation system.
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
Provides reliable and simultaneous control of propeller blade pitch angles, ensuring efficient thrust distribution during hover and forward flight, with fail-safe mechanisms to prevent drag in case of failures.
Implementation Method 1
a linear drive, which may be a power screw
Implementation Method 2
kinematic links which transfer the linear axial motion of the pitch plate along the propeller spin axis into rotary motion of the propeller blade roots
Implementation Method 3
The propeller pitch control mechanism may include springs or gas springs adapted to place the propeller blades in a low drag position in the event of failure
Data Source
AI summary
A propeller blade pitch control mechanism configured to adjust and control the blade pitch of the blades of a multi-blade propeller simultaneously. The pitch control mechanism may have a pitch plate which is raised or lowered along a liner path along an axial direction using a linear drive, which may be a power screw. The pitch plate is coupled to the blade roots with kinematic links which transfer the linear axial motion of the pitch plate along the propeller spin axis into rotary motion of the propeller blade roots, thereby controlling the pitch of the propeller blades. The propeller pitch control mechanism may include springs or gas springs adapted to place the propeller blades in a low drag position in the event of failure of the blade pitch control mechanism.