Propeller Pitch Control via Onboard Electrical Generation
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Solution Overview
Problem
Propeller pitch change systems in certain engine applications, such as pusher, counter-rotating, and tractor propeller systems, face challenges with high pressure hydraulic requirements, which can complicate the architecture and lead to issues like leakage and maintenance, especially when the gearbox does not support access to the propeller shaft.
Innovation Solution
A propeller system with an electrical generator mounted between the gearbox and the rotor hub generates electrical power within the rotating frame of reference to drive the pitch change system, eliminating the need for complex hydraulic systems by using a pitch change electric motor system and controller to vary the pitch of propeller blades, with power and control signals communicated directly within the rotational frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high pressure hydraulic systems are used for pitch change, then propeller pitch control is achieved, but system complexity and maintenance requirements increase
Solution Approach 1:
The patent replaces the traditional hydraulic mechanical system with an electrical system. An electrical generator mounted on the propeller shaft generates electrical power that drives an electrical motor within the rotor hub, which then actuates the pitch change mechanism. This substitution eliminates high pressure hydraulic lines, pumps, and associated components, thereby reducing system complexity while maintaining pitch control functionality.
2Ease of operation
If electrical power is supplied from stationary reference frame, then pitch change is achieved, but heavy slip-ring assemblies are required
Solution Approach 1:
The system generates its own electrical power onboard the rotating propeller assembly. The electrical generator is driven by the propeller shaft and produces electrical power that is used to drive the electrical motor for pitch change actuation. This self-service approach eliminates the need for heavy slip-ring assemblies that would be required to transmit electrical power from a stationary source to the rotating propeller.
3Adaptability or versatility
If gearbox does not support access to propeller shaft, then certain propeller configurations are enabled, but hydraulic power provision becomes complicated
Solution Approach 1:
By replacing the hydraulic system with an electrical system where the generator is directly mounted on the propeller shaft, the patent enables versatile propeller configurations (pusher, counter-rotating, tractor) without requiring complex hydraulic provisions. The electrical power generation and distribution system is more adaptable to different gearbox and propeller shaft access 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 simplifies the propeller system by eliminating hydraulic complexities, reducing maintenance, and supporting more-electric engines by generating power within the rotating frame, thereby enhancing reliability and efficiency in propeller pitch control.
Implementation Method 1
An electrical generator mounted between a gearbox and the rotor hub generates electrical power to drive the pitch change system
Data Source
AI summary
A propeller system includes a rotor hub which supports a multiple of propeller blades. An electrical generator is mounted between a gearbox and the rotor hub to generate electrical power to drive a pitch change system within the rotor hub.