Multi-Fan Tail-Sitter Propulsion for Controlled Flight 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, featuring propulsors positioned above and below the wings, controlled by a computing system to produce differential thrust, enabling controlled orientation transitions through a thrust differential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tail-sitter configuration is used for VTOL aircraft, then the aircraft can achieve vertical takeoff and landing capability, 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 segmented into multiple independent fans (at least three fans arranged in a triangular pattern) that can be controlled individually. This segmentation allows differential thrust production across different locations, enabling moment generation for orientation transitions while maintaining overall vehicle stability through coordinated control of each fan segment.
Solution Approach 2:
Different fans are positioned at specific locations (triangular arrangement) to create local thrust differences. By varying the thrust output of individual fans based on their spatial distribution, the system generates localized force imbalances that produce the necessary moments for orientation transitions, while the overall distribution maintains stability.
2Stability of the object's composition
If traditional propulsion systems are used for orientation transitions, then aircraft stability can be maintained, but the system requires heavy components that reduce weight and fuel efficiency
Solution Approach 1:
The same set of fans used for vertical lift generation is also used for orientation transitions and horizontal flight. The fans serve multiple functions: providing vertical thrust during takeoff/landing, generating differential moments for orientation transitions, and producing forward thrust during horizontal flight. This eliminates the need for separate heavy propulsion systems for each flight regime.
Solution Approach 2:
The propulsion system transitions dynamically between different operational modes by adjusting fan speeds and thrust distribution. The system adapts its thrust vectoring characteristics in real-time, shifting from symmetric thrust for vertical flight to asymmetric thrust for orientation transitions, and back to symmetric thrust for horizontal flight, all using the same propulsion components.
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 transitions between vertical and horizontal flight orientations, reducing the need for heavy components and improving weight and fuel efficiency, suitable for both commercial and military applications.
Implementation Method 1
The first propulsor has a fan positioned primarily above the pair of wings... The second propulsor has a fan positioned primarily below the pair of wings... the fan of the first propulsor and the fan of the second propulsor to produce different amounts of thrust
Data Source
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.