Aircraft Powerplant Reverse Thrust Control System
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Solution Overview
Problem
Propeller-driven aircraft face challenges in transitioning from forward to reverse thrust during landing, as applying increased engine power too soon can result in positive thrust rather than reverse thrust, due to the propeller blades operating in a zone of minimum rotational drag.
Innovation Solution
A method and system for controlling an aircraft powerplant with a variable-pitch propeller, which involves determining reverse thrust conditions based on aircraft airspeed and power lever position, triggering reverse thrust by decreasing propeller blade angle and increasing engine power at predetermined rates, and ending reverse thrust when specific speed thresholds are met or upon request.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pilot applies increase in engine power during propeller blade angle transition from forward to reverse pitch, then reverse thrust is generated, but positive thrust may occur if power is applied too soon
Solution Approach 1:
The control system automatically monitors propeller blade angle position and engine power parameters, and autonomously adjusts engine power to ensure reverse thrust is generated only when blade angle is in the correct range. This eliminates the need for pilot judgment and manual coordination, allowing the system to self-regulate power application timing based on real-time propeller state.
Solution Approach 2:
The control system continuously receives feedback from sensors monitoring propeller blade angle position and engine power output. This feedback loop enables the system to detect when the propeller blades are transitioning through the disking zone and automatically adjust engine power accordingly, preventing positive thrust by withholding power until the blade angle reaches the appropriate reverse pitch position.
2Measurement precision
If the pilot manually controls power application during propeller transition, then some degree of reverse thrust control is achieved, but precise timing and amount of reverse thrust cannot be ensured
Solution Approach 1:
The system replaces manual pilot mechanical control with an automated electronic control system that precisely measures propeller blade angle position using sensors. This electronic measurement and control system achieves superior timing precision compared to manual pilot judgment, automatically calculating the optimal moment to apply engine power based on real-time propeller state data.
Solution Approach 2:
The control system dynamically adjusts engine power parameters based on real-time propeller blade angle position. By continuously monitoring the blade angle parameter and using it to modulate engine power output, the system achieves precise control over both the timing and magnitude of reverse thrust, ensuring optimal performance during the propeller transition phase.
Data Source
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AI summary
Methods and systems for operating an aircraft powerplant (100) comprising an engine (110) coupled to a variable-pitch propeller (120) capable of generating forward and reverse thrust are described herein. A request to enable a mode for automated reverse thrust is received. Reverse thrust conditions are determined to have been met when the aircraft is on-ground, a blade angle of the propeller (120) is below a blade angle threshold and a position of a power lever (212) is at a selected idle region of the power lever (212). Reverse thrust of the propeller (120) is triggered when the mode for automated reverse thrust is enabled and the reverse thrust conditions have been met.