Electric Propeller Blade Pitch Actuation for Individual Blade Control
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Solution Overview
Problem
Existing aircraft propeller systems face inefficiencies and complexity in pitch control mechanisms, particularly due to reliance on hydraulically-powered systems that require high pressure oil flow and heavy, centrally located motors, which can be cumbersome and less efficient.
Innovation Solution
The implementation of a pitch change actuator system utilizing a high-torque servomotor or stepper motor connected to the propeller hub via anti-rotation features, with blade pitch sensors providing feedback to a controller for precise, individual control of each propeller blade's pitch angle, allowing for compact and efficient pitch adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydraulically-powered pitch change mechanisms are used, then pitch control capability is achieved, but system weight and complexity increase due to high pressure oil flow requirements and hydraulic valves
Solution Approach 1:
The patent replaces the hydraulic power transmission system with an electric motor directly mounted on the propeller hub. This substitution eliminates the need for hydraulic pumps, high-pressure oil lines, valves, and seals, thereby reducing system complexity while maintaining pitch control capability through direct electric actuation of the pitch change mechanism.
Solution Approach 2:
The invention extracts and removes the heavy hydraulic power transmission components from the propeller system. By eliminating the external hydraulic power source and its associated high-pressure fluid system, the patent reduces overall system weight and complexity while retaining the essential function of pitch control through a compact electric motor integrated directly on the hub.
2Ease of operation
If a large, heavy, centrally located motor is used for electric pitch change, then pitch control is achieved, but propeller balance and efficiency deteriorate
Solution Approach 1:
The patent segments the pitch control system by distributing individual pitch change mechanisms to each propeller blade rather than using a single centralized system. Each blade has its own compact electric motor mounted at the blade root, allowing independent pitch adjustment and maintaining propeller balance through distributed weight distribution rather than concentrated mass.
Solution Approach 2:
The invention transitions from a centralized axial arrangement to a distributed radial arrangement of motors. By mounting compact motors at the blade roots and utilizing the blade's structural geometry, the system achieves pitch control without compromising propeller balance, effectively using the blade structure itself as part of the actuation mechanism.
3Ease of operation
If hydraulically-powered pitch change mechanisms are used, then pitch control is achieved, but system weight increases due to hydraulic components
Solution Approach 1:
The patent substitutes electric motors with integrated direct-drive mechanisms for each propeller blade, eliminating the need for heavy hydraulic components such as pumps, reservoirs, high-pressure hoses, and control valves. This replacement dramatically reduces system weight while maintaining full pitch control capability through electric actuation.
Solution Approach 2:
The invention extracts and removes the entire hydraulic power transmission system from the propeller assembly. By eliminating external hydraulic power sources and high-pressure fluid systems, the patent achieves significant weight reduction while retaining pitch control functionality through compact electric motors mounted directly on the propeller hub.
4Ease of operation
If a centralized electric motor is used for pitch change, then pitch control is achieved, but individual blade control and aerodynamic balance are compromised
Solution Approach 1:
The patent segments the pitch control system into independent units, with each propeller blade equipped with its own electric motor and pitch change mechanism. This segmentation enables individual blade pitch adjustment, allowing for precise aerodynamic balancing and adaptive control of each blade independently, thereby enhancing both control capability and aerodynamic efficiency.
Solution Approach 2:
The invention implements local pitch control by providing dedicated motors and mechanisms at each blade root. This local quality approach allows each blade to be controlled independently according to its specific aerodynamic requirements, enabling precise adjustment of pitch angles to optimize performance and maintain aerodynamic balance across the entire propeller.
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 enables rapid and precise control of propeller blade pitch, improving aerodynamic balance and efficiency by allowing for individual control of each blade, reducing the need for heavy motors and hydraulic systems, and enhancing cyclic pitch control.
Implementation Method 1
A pitch change actuator, such as a high-torque servomotor or a stepper motor, may be disposed in the blade pocket and operably connected to rotate the propeller blade about a propeller blade axis
Implementation Method 2
One or more blade pitch sensors may be utilized to detect a pitch angle of the propeller blade
Data Source
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AI summary
A propeller assembly of an aircraft includes a hub (18), a plurality of propeller blades (20) extending from the hub and secured thereto and a propeller blade pitch change system located at at least one propeller blade of the plurality of propeller blades. The propeller blade pitch change system includes a pitch change actuator (36) located in the propeller blade, and a drive mechanism (46, 48, 50) operably connected to the pitch change actuator and to the propeller blade to urge rotation of the propeller blade about a propeller blade axis.