Three-Engine Rotary-Wing Aircraft Asymmetric Power Control
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Solution Overview
Problem
The development of a three-engine rotary-wing aircraft with unequal maximum powers poses challenges in responsiveness, stability, control, monitoring, and integration, making it difficult to achieve optimal performance and safety requirements, particularly in maintaining hover capability in case of an engine failure.
Innovation Solution
A rotary-wing aircraft with a main regulation system controlling two main engines according to a variable setpoint and a secondary engine regulated independently according to a constant setpoint, allowing for increased power and reduced oversizing of main engines, while maintaining reasonable control unit dimensions and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three identical engines are installed to meet safety requirements, then reliability is improved, but the engines must be oversized which increases mass, cost, and fuel consumption
Solution Approach 1:
The patent applies asymmetry by using three engines with unequal maximum powers instead of three identical engines. The secondary engine has a lower maximum power than the two main engines, allowing the main engines to be downsized while still meeting safety requirements for hover capability in case of engine failure.
Solution Approach 2:
The patent changes the power parameter distribution among engines. Instead of equal power distribution, it implements unequal power distribution where the secondary engine provides auxiliary power during specific flight phases (hover, take-off, landing) while the main engines provide primary propulsion, optimizing overall system performance.
2Reliability
If three identical engines are installed to ensure responsiveness, then reliability is improved, but control unit complexity and dimensions increase
Solution Approach 1:
The control system is segmented into a main control unit for the two main engines and a secondary control unit for the secondary engine. This segmentation allows each control unit to be optimized independently, reducing overall complexity while maintaining responsiveness.
Solution Approach 2:
The patent implements dynamic regulation where the secondary engine's power output is adjusted based on flight conditions. The secondary control unit regulates the secondary engine according to a variable setpoint that changes with flight phase, optimizing responsiveness while simplifying control logic.
3Reliability
If engines are oversized to meet safety requirements, then reliability is improved, but fuel consumption increases
Solution Approach 1:
The secondary engine operates periodically or intermittently based on flight phases rather than continuously. It provides supplemental power during critical phases (hover, take-off, landing) and can be deactivated during cruise flight, reducing overall fuel consumption while maintaining emergency power availability.
Solution Approach 2:
The secondary engine provides partial power supplementation rather than requiring the main engines to provide full emergency power capability. This partial action allows the main engines to be downsized, reducing their fuel consumption during normal operation while the secondary engine adds power only when needed.
Data Source
AI summary
The aircraft (1) has two main engines (11,12) for driving a main gearbox, which in turn drives rotation of a rotary wing (2). A main regulation system (15) regulates each main engine upon application of a variable set point. The aircraft also has a secondary engine (21) also capable of driving the gearbox. A secondary regulation system (25) regulates the secondary engine upon application of a constant set point independent from the main regulation system. An independent claim is also included for a method of driving rotation of a main gearbox driving rotation of a rotary wing of an aircraft.