Variable-Speed Aircraft Propulsion Rotors for Thrust-Lift Switching
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Solution Overview
Problem
Existing aircraft propulsion systems lack the ability to efficiently generate both propulsive thrust and lift in different directions, limiting their versatility and maneuverability.
Innovation Solution
Aircraft propulsion system with a gas turbine engine core that can rotate at different speeds to drive either a ducted propulsor rotor for thrust or an open rotor for lift, utilizing a transmission to decouple or couple these rotors based on operational mode, and a thrust control system to manage thrust generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single propulsor rotor is used for both thrust and lift generation, then device complexity is reduced, but the ability to generate propulsive thrust and lift efficiently in different directions deteriorates
Solution Approach 1:
The propulsion system is segmented into two separate rotors: a first propulsor rotor for generating propulsive thrust and a second propulsor rotor for generating propulsive lift. This segmentation allows each rotor to be optimized for its specific function, with the first rotor having blades arranged for thrust generation and the second rotor having blades arranged for lift generation, thereby resolving the contradiction between device complexity and directional adaptability.
Solution Approach 2:
The gas turbine engine core serves multiple functions by being configured to rotate the first propulsor rotor for thrust generation and the second propulsor rotor for lift generation. The engine core acts as a universal power source that can drive different propulsion modes (thrust and lift) through a common rotating structure, enabling multi-functionality without requiring separate engines for each function.
2Power
If the gas turbine engine core rotates at high speed to drive the first propulsor rotor for thrust, then propulsive thrust generation is improved, but the ability to drive the second propulsor rotor for lift at lower speed deteriorates
Solution Approach 1:
The system employs dynamic control of the rotating structure's speed to adapt to different propulsion modes. The gas turbine engine core can rotate the first propulsor rotor at a first rotational speed for thrust generation and the second propulsor rotor at a second rotational speed (less than 80% of the first speed) for lift generation. This dynamic speed adjustment enables the system to optimize power delivery for each function independently.
Solution Approach 2:
A transmission system acts as an intermediary between the gas turbine engine core and the propulsor rotors. The transmission includes a first transmission path for coupling the rotating structure to the first propulsor rotor and a second transmission path for coupling the rotating structure to the second propulsor rotor, allowing independent speed control and power transmission to each rotor based on operational requirements.
3Adaptability or versatility
If a transmission system is added to decouple or couple rotors based on operational mode, then adaptability is improved, but device complexity increases
Solution Approach 1:
The transmission system is designed as a multi-functional component that can perform multiple operations: it can couple the rotating structure to the first propulsor rotor for thrust mode, couple the rotating structure to the second propulsor rotor for lift mode, and decouple connections when not in use. This universal transmission mechanism enables mode switching without requiring separate coupling mechanisms for each function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient generation of propulsive thrust and lift in multiple directions, enhancing aircraft maneuverability and operational flexibility.
Implementation Method 1
a combustor section, a turbine section and a rotating structure
Implementation Method 2
The gas turbine engine core is configured to rotate the rotating structure at a first rotational speed during a first mode to drive the first propulsor rotor
Implementation Method 3
The gas turbine engine core is configured to rotate the rotating structure at a first rotational speed during a first mode to drive the first propulsor rotor
Data Source
AI summary
A propulsion system includes a first propulsor rotor, a second propulsor rotor and a gas turbine engine core. The first propulsor rotor is configured to generate propulsive thrust. The second propulsor rotor is configured to generate propulsive lift. The gas turbine engine core includes a compressor section, a combustor section, a turbine section and a rotating structure. The rotating structure includes a turbine rotor within the turbine section. The gas turbine engine core is configured to rotate the rotating structure at a first rotational speed during a first mode to drive the first propulsor rotor to generate the propulsive thrust. The gas turbine engine core is configured to rotate the rotating structure at a second rotational speed during a second mode to drive the second propulsor rotor to generate the propulsive lift. The second rotational speed may be less than eighty percent of the first rotational speed.