Variable Pitch Wing Fans for VTOL Stability and Cruise Efficiency
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Solution Overview
Problem
Aircraft capable of vertical takeoff and landing face a discrepancy in efficiency between vertical takeoff and landing and forward flight, with existing designs being well-suited for vertical thrust but not for efficient high-speed cruise.
Innovation Solution
The aircraft incorporates a hybrid electric propulsion system with multiple electric fans integrated into the wings, including variable pitch outermost fans and fixed-pitch interior fans, driven by a turboshaft engine and electric machine, and a wing design with variable geometry for enhanced thrust and stability, allowing for efficient vertical and forward flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If propulsors are vectored to generate vertical thrust for takeoff and landing, then vertical takeoff and landing capability is achieved, but forward flight efficiency deteriorates
Solution Approach 1:
The propulsion system is segmented into multiple independent electric fans distributed along the wing span, with each fan capable of independent pitch control. This segmentation allows different fans to operate in different modes simultaneously - outer fans providing vertical thrust for VTOL while inner fans optimized for forward flight, thus resolving the contradiction between VTOL capability and forward flight efficiency
Solution Approach 2:
The propulsors employ variable pitch mechanisms that allow dynamic adjustment of blade angle during operation. The outermost fans have variable pitch capability to optimize performance across different flight phases - providing vertical thrust during takeoff/landing and transitioning to efficient forward thrust during cruise, thereby maintaining both VTOL capability and forward flight efficiency
2Power
If propulsors are optimized for vertical thrust generation, then vertical takeoff and landing performance is improved, but cruise efficiency deteriorates
Solution Approach 1:
Different regions of the wing are assigned different fan types with locally optimized characteristics. Inner fans use fixed-pitch design optimized for forward flight efficiency, while outer fans use variable-pitch design optimized for vertical thrust generation. This local differentiation allows each region to operate at optimal efficiency for its specific function, resolving the contradiction between vertical thrust power and cruise energy efficiency
Solution Approach 2:
The hybrid propulsion system achieves multi-functionality by combining fixed-pitch and variable-pitch fans in a single configuration. The system can universally perform both vertical takeoff/landing and efficient forward cruise by appropriately controlling different fan groups, eliminating the need for separate optimization designs for different flight phases
3Stability of the object's composition
If variable pitch fans are used for stability, then aircraft stability is improved, but device complexity increases
Solution Approach 1:
The variable pitch mechanism is segmented and applied only to the outermost fans where it provides maximum stability benefit for VTOL operations, while inner fans use simpler fixed-pitch design. This segmented application reduces overall system complexity compared to making all fans variable pitch, while still achieving the stability improvement through the critical outer fans
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
This configuration enables improved stability and efficiency in both vertical takeoff and landing, as well as high-speed cruise, by optimizing thrust generation and wing geometry, resulting in a more versatile and efficient aircraft.
Implementation Method 1
a plurality of electric fans integrated into the wing and oriented to generate thrust along the vertical direction
Implementation Method 2
the outermost electric fan along the transverse direction relative to the fuselage, the outermost electric fan being a variable pitch fan to provide increased stability to the aircraft
Data Source
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AI summary
An aircraft (10) includes a fuselage (18); a wing coupled to, and extending from, the fuselage (18); and a propulsion system (32). The propulsion system (32) includes a plurality of electric fans integrated into the wing and oriented to generate thrust along a vertical direction (V), the plurality of electric fans arranged along a length of the wing and including an outer-most electric fan along a transverse direction (T) relative to the fuselage (18). The outer-most electric fan is at least one of a variable pitch fan or a variable speed fan to provide increased stability to the aircraft (10).