Rotorcraft Energy Maximizer for One-Engine-Inoperative Landing
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Solution Overview
Problem
Current rotor speed control systems in rotorcraft face challenges during single engine inoperative events, particularly in maximizing safe landing capability, as they either result in excessive weight, increased pilot workload, or transient loss of lift due to inadequate power management.
Innovation Solution
A system and method that utilize an energy maximizer command to reduce collective pitch only when the engine is at or near its operating limit, preventing a force-fight between the engine controller and collective governor, and ensuring lift is preserved until the engine reaches its limit, transitioning from throttle to collective governing when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full time rotor speed governing with collective throttle command is used, then rotor speed is maintained, but pilot response to engine failure is degraded
Solution Approach 1:
The system dynamically switches between throttle governing and collective governing modes based on engine power availability. During normal operation, throttle governing maintains rotor speed. Upon engine failure, the system transitions to collective governing when the engine reaches its limit, optimizing both automated control and pilot response capability
Solution Approach 2:
The system changes the governing parameter from throttle position to collective pitch angle based on engine power availability. This parameter switching allows the system to adapt to different operational states, maintaining rotor speed through automated control when possible while preserving pilot response capability when engine power is sufficient
2Use of energy by moving object
If collective pitch is reduced immediately upon loss of power, then power management is optimized, but transient loss of lift occurs
Solution Approach 1:
The system delays collective pitch reduction until the engine has already reached its maximum power and is unable to provide any more power to control rotor speed. This preliminary action ensures that all available engine power is utilized before reducing lift-generating capacity
Solution Approach 2:
The system preserves lift by maintaining collective pitch until absolutely necessary, cushioning against transient lift loss by keeping the rotor system powered as long as possible before transitioning to collective governing
3Stability of the object's composition
If a high inertia rotor is used to prevent rotor speed decrease, then rotor speed stability is improved, but additional weight is added
Solution Approach 1:
The system replaces the mechanical solution of high inertia rotor design with an automated control system that governs rotor speed through throttle and collective actuation. This substitution achieves rotor speed stability without the penalty of additional rotor weight
Solution Approach 2:
The automated control system continuously monitors engine power availability and autonomously adjusts throttle and collective settings to maintain rotor speed, eliminating the need for pilot intervention and providing self-service speed stabilization
Data Source
AI summary
A method of preserving rotor speed during a one engine inoperative operation of an rotorcraft, the method can include: detecting a failure of a first engine; monitoring an engine parameter associated with a second engine; using a computer processor to compare the engine parameter to an engine limit; and commanding a decrease collective pitch command when the engine parameter is within a predefined range of the engine limit.