Propeller Propulsion Pitch Control Using Shared Speed Sensing
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Solution Overview
Problem
Propeller propulsion systems in aircraft require multiple independent pitch control and protection systems, leading to increased component count, cost, and weight due to the need for multiple sensors to measure propeller and prime mover speeds.
Innovation Solution
A propeller propulsion system that re-uses a prime mover speed sensor to determine propeller speed, reducing the overall number of sensors required while maintaining independence by using an additional speed sensor for each control and protection unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple independent pitch control and protection systems are used, then system reliability is improved, but device complexity and component count increase
Solution Approach 1:
The prime mover speed sensor is designed to serve multiple functions: it provides speed signals to both the pitch control system and the protection system. This multi-functional sensor replaces what would traditionally require separate sensors for each system, reducing component count while maintaining the independence and reliability of both control pathways
2Measurement precision
If multiple speed sensors are used for pitch control and protection systems, then measurement accuracy is improved, but weight and cost increase
Solution Approach 1:
A single prime mover speed sensor provides speed measurements that are utilized by both the pitch control system and the protection system. This eliminates the need for separate speed sensors, thereby reducing weight while maintaining accurate speed measurement capability for both independent control pathways
3Reliability
If multiple speed sensors are used for pitch control and protection systems, then system independence is improved, but cost increases
Solution Approach 1:
The prime mover speed sensor serves as a shared resource for both the pitch control system and the protection system. Although the sensor itself is shared, the control and protection units remain independent in their processing and decision-making, maintaining system independence while reducing the total component count and associated costs
Data Source
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AI summary
A propeller propulsion system (500) is provided comprising a prime mover comprising at least one spool (330), a propeller (304) arranged to be driven by the spool, a pitch adjustment subsystem (508) comprising an electronic control unit (602) and an electronic protection unit (604), a prime mover speed sensor (512) arranged to detect a rotation speed of the spool; and an additional speed sensor (514) arranged to detect the rotation speed of the spool or arranged to detect a rotation speed of the propeller. A first of the electronic control unit (602) and the electronic protection unit (604) is arranged to use an output (N2_A, N2_B) from the prime mover speed sensor (512) to determine the rotation speed of the propeller; and a second of the electronic control unit (602) and the electronic protection unit (604) is arranged to use an output (NP_A, NP_B) from the additional speed sensor (514) to determine the rotation speed of the propeller.