Swivel Rotor Propulsion for Vectored Thrust and OEI Stability
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Solution Overview
Problem
VTOL aircraft face challenges in efficiently managing thrust vectoring and center of gravity shifts, particularly in one engine inoperative (OEI) conditions, which affects stability and reduces the performance of remaining engines, leading to increased costs, size, and weight of propulsion systems.
Innovation Solution
The implementation of a propulsion assembly with a rotor system that can swivel about a pivot axis, changing the gimbal angle to adjust the rotor axis and thrust vectors, allowing for efficient thrust vectoring and center of gravity management, enabling the aircraft to maintain stability and reduce thrust requirements on remaining engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VTOL aircraft use conventional propulsion systems without movable rotor systems, then the structure is simpler, but the aircraft cannot efficiently manage thrust vectoring and center of gravity shifts in OEI conditions
Solution Approach 1:
The rotor system is made dynamically adjustable by allowing it to swivel about a pivot axis, enabling the rotor to change its orientation relative to the aircraft body. This dynamic capability allows the propulsion system to adapt to OEI conditions by repositioning thrust vectors to compensate for lost engine thrust, thereby maintaining stability without requiring excessive structural complexity.
Solution Approach 2:
The system changes the orientation parameter of the rotor axis by swiveling it to different gimbal angles. This parameter change allows the thrust vector to be redirected, enabling the aircraft to maintain proper center of gravity alignment and stability in OEI conditions. The flight control system activates specific operational modes that adjust the rotor orientation parameter to optimize performance.
2Power
If the rotor system can swivel to change gimbal angle for thrust vectoring, then thrust requirements on remaining engines are reduced, but the device complexity increases
Solution Approach 1:
The rotor system incorporates a swiveling mechanism that allows dynamic adjustment of the rotor axis orientation. This dynamic capability enables the remaining engines to operate at reduced thrust levels by vectoring the thrust force through the movable rotor, thereby reducing overall power requirements while managing the added mechanical complexity of the swiveling mechanism.
Solution Approach 2:
The swiveling rotor system serves multiple functions: it provides thrust vectoring capability, enables center of gravity management, and allows the aircraft to operate in various flight modes (vertical hover, forward flight, transition). This multi-functionality justifies the added complexity by eliminating the need for separate systems to achieve each individual function.
3Adaptability or versatility
If the rotor system is made tiltable for forward flight capability, then the aircraft achieves both vertical lift and forward thrust, but the system complexity and weight increase
Solution Approach 1:
The tiltable rotor system integrates multiple flight capabilities into a single propulsion assembly. The same rotor system that provides vertical lift for hover also generates forward thrust when tilted, eliminating the need for separate propulsion systems for different flight modes. This multi-functionality reduces overall weight despite the added complexity of the tilting mechanism.
Solution Approach 2:
The rotor system incorporates a tilting mechanism that allows dynamic adjustment of the rotor plane orientation between horizontal (for vertical lift) and vertical (for forward thrust) positions. This dynamic adaptability enables the aircraft to transition between flight modes using the same propulsion system, reducing total weight by eliminating redundant components.
4Ease of operation
If the rotor system swivels about a fixed pivot axis, then the aircraft can change attitude and center of gravity, but the control complexity increases
Solution Approach 1:
The flight control system uses feedback from sensors to monitor the rotor system's position and the aircraft's attitude. Based on this feedback, the control system automatically adjusts the rotor swiveling angle to achieve desired attitude changes and center of gravity positioning. This feedback mechanism simplifies operation while managing the complexity of the control system through automated control.
Solution Approach 2:
The system pre-configures operational modes with predetermined rotor swiveling angles and attitudes. When a mode is activated, the rotor system automatically swivels to the pre-calculated optimal position, reducing real-time control complexity. The flight control system stores and executes pre-planned sequences for common operational scenarios, simplifying pilot input requirements.
Data Source
AI summary
A vehicle comprises a propulsion assembly that includes a rotor system configured to swivel about a pivot axis and a flight control system in communication with the propulsion assembly. In one embodiment, the pivot axis is fixedly oriented at an angle relative to a lateral axis of the vehicle in a plane defined by a longitudinal axis of the vehicle. The flight control system is configured to activate a particular operational mode of the propulsion assembly, in which the rotor system is configured to swivel about the pivot axis to move a rotor axis of the rotor system from a first gimbal angle to a second gimbal angle. In various embodiments, the gimbal angle is configured to change a center of gravity, or direction of thrust vectors, or attitude of the vehicle. The operational mode may comprise a one engine inoperative (OEI) mode in an example embodiment.