Aircraft Propeller Pitch and Idle Control System
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Solution Overview
Problem
Gas turbine engines for aircraft often require manual adjustment of multiple input devices to minimize thrust and fuel consumption during ground conditions, leading to increased brake usage and potential propeller wear due to undesired vibratory modes, necessitating a system to determine minimum pitch and idle conditions for improved operation.
Innovation Solution
A method and system using a single operator-manipulated throttle input device to determine the minimum propeller pitch setting and gas generator idle speed, incorporating a controller with control logic to adjust these settings based on operating conditions, such as weight on wheels signals and throttle lever positions, to optimize ground operation and mitigate propeller operation in an avoid band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single idle setting (flight idle) is used, then the engine delivers sufficient thrust for flight conditions, but during ground conditions it delivers excessive thrust increasing brake usage and fuel consumption
Solution Approach 1:
The patent applies dynamics by making the idle setting adjustable between at least two positions (flight idle and ground idle) rather than fixed. The controller dynamically selects the appropriate idle setting based on detected aircraft conditions (ground vs flight), allowing the engine to deliver appropriate thrust levels for each condition, reducing excessive thrust and fuel consumption during ground operations.
2Loss of energy
If the operator manually adjusts propeller pitch angle to reduce thrust during ground conditions, then fuel consumption decreases, but the operator must continuously monitor and adjust multiple input devices to maintain proper operation
Solution Approach 1:
The patent applies self-service by implementing an automated control system that detects aircraft conditions (ground vs flight) and automatically adjusts the idle setting and propeller pitch angle without requiring continuous operator intervention. The controller monitors parameters and autonomously selects the appropriate idle setting and pitch angle, reducing the operator's workload while maintaining optimal fuel consumption.
Solution Approach 2:
The system uses feedback by detecting aircraft conditions (weight on wheels, throttle lever position) and using this information to automatically adjust the idle setting and propeller pitch. The controller receives feedback from sensors and continuously adjusts parameters to maintain optimal operation, eliminating the need for manual monitoring and adjustment of multiple input devices.
3Loss of energy
If the propeller operates at low pitch angles to minimize thrust, then fuel consumption reduces, but the propeller may operate in an avoid band causing excessive wear and vibratory modes
Solution Approach 1:
The controller uses feedback from detected aircraft conditions to determine the appropriate idle setting and propeller pitch angle. By detecting whether the aircraft is on ground or in flight, the controller selects pitch angles that minimize fuel consumption while avoiding the avoid band range that causes excessive wear and vibration, thus maintaining both fuel efficiency and propeller reliability.
Solution Approach 2:
The patent applies parameter changes by adjusting the idle setting between at least two distinct positions (flight idle and ground idle) and corresponding pitch angles. This discrete parameter change ensures the propeller operates at optimal angles for each condition, avoiding the harmful avoid band while minimizing fuel consumption during ground operations.
4Measurement precision
If multiple operator manipulated input devices are used for precise control, then operation accuracy improves, but the device complexity and operator workload increase
Solution Approach 1:
The patent applies universality by designing a control system where a single idle setting control mechanism performs multiple functions: it adjusts engine thrust, controls propeller pitch angle, and selects appropriate operating modes (ground idle or flight idle). This multi-functional approach maintains control accuracy while reducing the number of separate input devices required.
Solution Approach 2:
The system merges the control functions of idle setting adjustment and propeller pitch control into an integrated system. The controller combines detection of aircraft conditions with automated adjustment of both idle setting and pitch angle, consolidating multiple control functions into a unified system that reduces device complexity while maintaining precise control accuracy.
Data Source
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AI summary
The present disclosure is directed to a system and a method for determining an aircraft (10) minimum low pitch setting for a propeller assembly (30) and minimum gas generator idle speed for a gas generator (100), in which the propeller assembly (30) and the gas generator (100) together comprise a gas turbine engine. The method comprises determining, via one or more controllers (210), an operating condition of the aircraft (10) based at least on a weight on wheels (WoW) signal and a throttle lever (22) position. The WoW signal produces a first mode or a second mode different from the first mode, and the throttle lever position defines at least a takeoff position and an idle power position.