Embedded Cross-Flow Fan Airfoil for VTOL Thrust Vectoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing VTOL and STOL aircraft propulsion systems require complex structures and mechanisms due to the need for rotating or tilting entire vehicles and engines, and cross-flow fans are not efficiently integrated into aircraft wings for both high-speed and vertical flight applications.
Innovation Solution
A system with an airfoil, embedded cross-flow fan, and exit duct that allows for distributed propulsion and vectored thrust, using a rotatable flap and flexlip to adjust airflow direction for efficient vertical and horizontal flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cross-flow fans are embedded within conventional airplane wings with shafts and couplings connecting them to wing-tip and root-mounted gas turbines, then distributed propulsion is achieved, but device complexity increases and fan size is limited
Solution Approach 1:
The patent extracts the gas turbine engines from the wing structure and places them in the fuselage, eliminating the need for shafts and couplings to connect distributed fans along the wing. Each fan is independently powered, simplifying the overall system architecture while maintaining distributed propulsion benefits.
Solution Approach 2:
The propulsion system is segmented into independent fan units distributed along the wing trailing edge, each with its own mounting bracket and control mechanism. This segmentation allows for simplified individual components rather than a complex interconnected shaft system.
2Adaptability or versatility
If cross-flow fans are used for VTOL flight with ground-visible occupants, then vertical flight capability is achieved, but the craft occupants must face skyward with ground semi-visible behind them which is unacceptable
Solution Approach 1:
The patent employs a rotatable exit duct with variable geometry that can dynamically adjust the thrust vector direction. This allows the propulsion system to adapt between horizontal flight mode and vertical flight mode, enabling occupants to maintain comfortable orientation while achieving VTOL capability.
Solution Approach 2:
The exit duct geometry parameters are changed through rotation and adjustment mechanisms, transforming the thrust vector from vertical to horizontal or intermediate angles. This parameter adjustment resolves the contradiction between vertical flight capability and acceptable occupant orientation.
3Stress or pressure
If conventional HVAC-type CFF housing with 90 degree turn from inlet to outlet is used, then high pressure coefficient is achieved, but propulsive efficiency for forward flight is reduced
Solution Approach 1:
The exit duct is designed with variable geometry that can dynamically adjust the flow turn angle. For forward flight, the duct configuration minimizes the turn angle to improve propulsive efficiency, while for VTOL operations it can achieve the necessary 90-degree turn to maintain high pressure coefficient.
Solution Approach 2:
The exit duct design serves multiple functions: it can configure for high pressure coefficient during VTOL operations and reconfigure for optimal propulsive efficiency during forward flight. This multi-functionality resolves the contradiction between the two performance requirements.
4Object-generated harmful factors
If engine pylon/nacelle support structure is eliminated with embedded propulsion, then parasitic drag is reduced by up to 18 to 20%, but device complexity in wing integration increases
Solution Approach 1:
The fan assemblies are merged with the wing trailing edge structure, with fans mounted in brackets that integrate with the airfoil. This combination eliminates separate engine pylons and nacelles, reducing parasitic drag while the modular bracket design keeps the integration complexity manageable.
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
The system achieves high propulsive efficiency in forward flight and vertical take-off/landing with reduced complexity and parasitic drag, enabling compact aircraft design and efficient thrust vectoring.
Implementation Method 1
The CFF uses an impeller with forward curved blades, placed in a housing consisting of a rear wall and vortex wall
Implementation Method 2
an exit duct for the cross-flow fan configured to provide distributed flow along the trailing edge of the system to achieve high propulsive efficiency in forward flight and a substantially vertical jet for vertical take-off and landing
Implementation Method 3
at least one airfoil extending from a leading edge to a trailing edge
Implementation Method 4
The system is further provided with a flap rotatable about a rotor axis, where the flap has an upper face and a lower face
Data Source
AI summary
A system for providing lift, propulsion and control for an aircraft vehicle that facilitates vertical take-off and landing/short take-off and landing operations is described. The system is configured to provide an airfoil that has a leading and a trailing edge, a cross flow fan partially embedded in the airfoil and mounted adjacent to the trailing edge of the airfoil and an exit duct for the cross flow fan to provide distributed flow along the trailing edge of the system to achieve high propulsive efficiency in forward flight and a substantially vertical jet for vertical take-off and landing.