Multi-Fan VTOL Propulsion for Stable Tail-Sitter Transitions
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Solution Overview
Problem
Transitioning fixed-wing Vertical Take-Off and Landing (VTOL) aircraft, particularly tail-sitter configurations, from vertical to horizontal orientations and vice versa is challenging due to the difficulty in producing a thrust moment while maintaining stability.
Innovation Solution
A multi-fan propulsion system with individually controllable fans positioned above and below the wings, combined with a computing system that adjusts thrust differentials between fans to control orientation transitions, allowing for stable transitions between vertical and horizontal flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tail-sitter configuration is used for VTOL aircraft, then vertical takeoff and landing capability is achieved, but transitioning from vertical to horizontal orientation becomes challenging due to difficulty in producing thrust moment while maintaining stability
Solution Approach 1:
The propulsion system is divided into multiple independent fan units (first fan above wings, second fan below wings, third and fourth fans laterally positioned) that can be controlled individually. This segmentation allows independent adjustment of thrust from each fan to produce the necessary thrust moment for orientation transitions while maintaining stability, directly resolving the contradiction between VTOL capability and transition difficulty
Solution Approach 2:
The patent implements dynamic control of fan thrust outputs based on aircraft orientation. The computing system continuously adjusts the thrust produced by each fan according to the current orientation and desired transition, enabling the propulsion system to adapt in real-time during transitions between vertical and horizontal orientations, thereby making the transition process manageable despite the tail-sitter configuration
2Stability of the object's composition
If traditional stabilization components are added to maintain stability during transitions, then orientation control improves, but aircraft weight increases
Solution Approach 1:
The patent replaces traditional mechanical stabilization components (such as heavy tail surfaces, stabilizers, or counterweights) with a control-based approach using the multi-fan propulsion system. The computing system uses differential thrust control from the segmented fans to provide stability during transitions, eliminating the need for additional mechanical stabilization structures and thereby maintaining low aircraft weight while achieving improved stability control
Solution Approach 2:
The patent changes the operational parameters of the existing propulsion system (thrust output of each individual fan) to achieve stability during transitions. By dynamically adjusting thrust parameters rather than adding physical mass, the system maintains stability without increasing aircraft weight, directly resolving the contradiction between stability and weight
3Reliability
If heavier components are used to enhance transition control, then orientation transition stability improves, but fuel consumption increases
Solution Approach 1:
The patent replaces heavy mechanical components with electronic control of the propulsion system. The computing system orchestrates differential thrust from the segmented fans to provide reliable transition control, eliminating the need for heavy components that would increase fuel consumption while maintaining or improving transition stability, thus resolving the contradiction between reliability and energy use
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 controlled and efficient orientation transitions for VTOL aircraft, reducing the need for heavy components, resulting in weight and fuel savings, and enhancing stability during takeoffs and landings.
Implementation Method 1
Each propulsor includes a rotatable fan operable to produce thrust
Data Source
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AI summary
An aircraft equipped with a multi-fan propulsion system for controlling flight orientation transitions is provided. In one example aspect, an aircraft includes a fuselage and a pair of wings. The aircraft includes a propulsion system having a first propulsor and a second propulsor each mounted to the fuselage. The first propulsor has a fan positioned primarily above and the second propulsor has a fan positioned primarily below the pair of wings. The aircraft also includes a computing system having one or more processors configured to cause, in response to a demand to change an orientation of the aircraft for a flight orientation transition, the fans of the first and second propulsors to produce different amounts of thrust with respect to one another so that the aircraft performs the flight orientation transition. The thrust differential causes the aircraft to transition between orientations.