Multi-Fan VTOL Propulsion for Stable Orientation Transitions
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Solution Overview
Problem
Transitioning fixed-wing Vertical Take-Off and Landing (VTOL) aircraft from vertical to horizontal orientation and vice versa is challenging, particularly for tail-sitter configurations, due to the difficulty in producing a thrust moment while maintaining aircraft stability.
Innovation Solution
An aircraft equipped with a multi-fan propulsion system, including a first propulsor above and a second propulsor below the wings, controlled by a computing system to produce differential thrust for orientation transitions, allowing controlled transitions between vertical and horizontal flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional propulsion systems are used in tail-sitter VTOL aircraft, then the aircraft can achieve vertical takeoff and landing capability, but the aircraft experiences difficulty in producing thrust moment while maintaining stability during orientation transitions
Solution Approach 1:
The propulsion system is divided into multiple independent fans (at least three fans arranged in a triangular pattern) that can be controlled individually. This segmentation allows differential thrust generation across different locations on the aircraft, enabling precise control of both thrust magnitude and thrust moment during orientation transitions while maintaining overall flight stability.
Solution Approach 2:
Each fan in the propulsion system can produce different thrust levels independently. By varying the thrust output of specific fans located at different positions (such as fans above and below the wings), the system creates localized thrust differences that generate the necessary moments for orientation changes without compromising overall aircraft stability.
2Reliability
If heavy components are added to conventional VTOL aircraft to improve transition control, then orientation transition stability improves, but aircraft weight increases and fuel efficiency decreases
Solution Approach 1:
The system replaces traditional mechanical stabilization components (such as heavy gyros, counterweights, or mechanical linkages) with an electronically controlled multi-fan propulsion system. By using independent control of multiple fans to generate differential thrust moments, the aircraft achieves stable orientation transitions without requiring additional heavy mechanical stabilization equipment, thereby reducing overall aircraft weight and improving fuel efficiency.
3Adaptability or versatility
If differential thrust is produced by multiple fans during orientation transitions, then controlled transition between vertical and horizontal flight is achieved, but the complexity of the propulsion system increases
Solution Approach 1:
The multi-fan propulsion system serves multiple functions: it provides vertical lift during takeoff and landing, generates forward thrust during horizontal flight, and creates differential thrust moments for orientation transitions. By making each fan and the propulsion system as a whole multi-functional, the design achieves versatile flight mode transitions without requiring separate dedicated systems for each function, thereby managing complexity while enhancing capability.
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 stable and controlled orientation transitions, reducing the need for heavy components, resulting in weight and fuel savings, and enhancing endurance for VTOL aircraft.
Implementation Method 1
the fan of the first propulsor and the fan of the second propulsor to produce different amounts of thrust with respect to one another so that the aircraft performs the flight orientation transition
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.