Aircraft Propulsion System Variable Pitch Rotor VTOL Transition
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Solution Overview
Problem
Existing aircraft propulsion systems lack the ability to efficiently alternate between horizontal propulsion and vertical lift, which is crucial for multi-directional flight capabilities, particularly in vertical take-off and landing (VTOL) and short take-off and vertical landing (STOVL) operations.
Innovation Solution
A propulsion system incorporating a gas turbine engine core with a first propulsor rotor and a second propulsor rotor, where the first propulsor rotor is configured with variable pitch blades that pivot between thrust and idle positions to optimize horizontal thrust in one mode and minimize it in another, while the second propulsor rotor generates vertical lift, utilizing a transmission to decouple and couple the rotors based on operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single propulsor rotor is used for both horizontal propulsion and vertical lift, then device complexity is reduced, but the ability to efficiently alternate between horizontal propulsion and vertical lift deteriorates
Solution Approach 1:
The propulsion system is segmented into two separate rotors: a first propulsor rotor for horizontal propulsion and a second propulsor rotor for vertical lift. This segmentation allows each rotor to be optimized for its specific function, with the first rotor having variable pitch blades for horizontal thrust control and the second rotor configured for vertical lift generation, thereby resolving the contradiction between structural simplicity and multi-directional capability.
Solution Approach 2:
The gas turbine engine core serves multiple functions by being able to drive both the first propulsor rotor for horizontal propulsion and the second propulsor rotor for vertical lift through a transmission system. This multi-functionality allows a single engine to provide both horizontal and vertical propulsion capabilities, addressing the versatility requirement without requiring separate propulsion systems.
2Adaptability or versatility
If variable pitch blades are used on the first propulsor rotor to control horizontal thrust, then adaptability between flight modes is improved, but device complexity increases
Solution Approach 1:
The first propulsor rotor incorporates variable pitch blades that can dynamically adjust their angle of attack during operation. These blades are configured to pivot between a thrust position for horizontal propulsion and an idle position to minimize thrust during vertical lift operations. This dynamic adjustability allows the same rotor structure to serve multiple flight modes, improving adaptability while managing complexity through integrated blade design.
3Power
If the first propulsor rotor generates high horizontal thrust during vertical mode, then propulsion power is improved, but vertical lift capability deteriorates
Solution Approach 1:
The propulsion function is segmented between two separate rotors with distinct roles: the first propulsor rotor is dedicated to horizontal thrust generation with variable pitch blades optimized for forward propulsion, while the second propulsor rotor is dedicated to vertical lift generation. This functional segmentation ensures that high horizontal thrust does not compromise vertical lift capability, as each rotor is independently optimized for its specific propulsion direction.
Solution Approach 2:
A transmission system acts as an intermediary between the gas turbine engine core and the two propulsor rotors. The transmission selectively couples the engine to either the first propulsor rotor for horizontal propulsion or the second propulsor rotor for vertical lift, preventing simultaneous operation that would create conflicting thrust directions. This intermediary mechanism ensures optimal performance in each flight mode without compromising the other.
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 the aircraft to efficiently transition between horizontal flight and vertical lift operations, significantly increasing thrust in forward flight modes and reducing horizontal thrust during vertical modes, thereby enhancing take-off, landing, and hovering capabilities.
Implementation Method 1
The first propulsor rotor includes a plurality of variable pitch blades. The variable pitch blades include a first blade configured to pivot between a thrust position and an idle position.
Implementation Method 2
a gas turbine engine core, a first propulsor rotor and a second propulsor rotor. The gas turbine engine core includes a compressor section, a combustor section, a turbine section and a rotating structure.
Implementation Method 3
The transmission is configured to couple the rotating structure to the second propulsor rotor during the second mode.
Data Source
AI summary
A propulsion system is provided for an aircraft. This aircraft propulsion system includes a gas turbine engine core, a first propulsor rotor and a second propulsor rotor. 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 first propulsor rotor is rotatably driven by the rotating structure during a first mode and a second mode. The first propulsor rotor includes a plurality of variable pitch blades. The variable pitch blades include a first blade configured to pivot between a thrust position and an idle position. The first blade is in the thrust position during the first mode. The first blade is in the idle position during the second mode. The second propulsor rotor is rotatably driven by the rotating structure during the second mode.