Fluidic Collapsible Ejector Propulsion for VTOL Transitions
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Solution Overview
Problem
Existing VTOL and STOL aircraft propulsors, such as rotary wings and tilting rotors, are limited by high complexity, weight, and speed limitations, while fixed ducted fans are inefficient for non-vertical flight segments, and eVTOL platforms face noise and inefficiency issues with propellers, limiting payload and speed capabilities.
Innovation Solution
An adaptive propulsive system using collapsible ejectors and nozzles integrated with air compressors, which deploy and retract based on flight phases to optimize thrust and lift, employing Upper Surface Blown lift augmentation and boundary layer ingestion to enhance lift and reduce drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rotary wings or tilting rotors are used for VTOL propulsion, then vertical take-off capability is achieved, but device complexity and weight increase significantly
Solution Approach 1:
The aircraft propulsion system is segmented into multiple independent ejector units distributed across the wing structure, with each ejector capable of independent operation. This segmentation allows the system to achieve VTOL capability through coordinated operation of multiple simple units rather than a single complex rotary wing or tilting rotor assembly.
Solution Approach 2:
The ejector-based propulsion system serves multiple functions: it provides vertical lift during take-off and landing, transitions to horizontal thrust during cruise flight, and can operate in various configurations by adjusting the number and orientation of active ejectors. This multi-functionality replaces the need for separate specialized propulsion systems for different flight phases.
2Device complexity
If fixed ducted fans are used for propulsion, then structural simplicity is maintained, but efficiency decreases during non-vertical flight segments
Solution Approach 1:
The ejector propulsion system transitions from a static fixed configuration to a dynamic adaptive configuration. During vertical flight, all ejectors operate in the vertical orientation. During horizontal flight, the system dynamically adjusts by deactivating certain ejectors or changing their orientation to provide optimal horizontal thrust, thereby maintaining efficiency across different flight regimes while keeping the overall structure relatively simple.
3Force
If propellers are used for eVTOL platforms, then vertical lift is generated, but noise and inefficiency increase
Solution Approach 1:
The system replaces mechanical rotating propellers with pneumatic ejectors that use compressed air to generate thrust. This pneumatic approach eliminates the mechanical noise associated with rotating blades while maintaining vertical lift capability. The ejectors create thrust through controlled air expansion rather than aerodynamic blade rotation, significantly reducing noise generation.
4Power
If traditional propulsors are used, then propulsion function is achieved, but payload capacity is limited due to weight
Solution Approach 1:
The ejector units are designed with flexible, collapsible structures that can be compressed into compact forms when not in use. This flexibility allows the propulsion system to occupy minimal space and contribute minimal weight to the aircraft structure, while still providing sufficient thrust when deployed. The thin-film construction of the ejectors further reduces material weight compared to traditional rigid propulsor 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 vertical take-off and high-speed flight by doubling lift and reducing drag, allowing stable transitions and efficient operation across various flight regimes without the limitations of traditional propulsors, with improved payload capacity and reduced noise.
Implementation Method 1
They are directed into an array of ejectors on the upper and lower surfaces of the wing and body that utilize the Coanda effect
Implementation Method 2
atmospheric air is compressed by an air compressor to high pressure
Implementation Method 3
employing Upper Surface Blown lift augmentation and boundary layer ingestion to enhance lift and reduce drag
Data Source
AI summary
An ejector system is constructed of a soft yet strong material such as silicone-based material which can be pressed to conform within a small space and stowed when inactive and can be expanded or stretched by mechanical, pneumatic or hydraulic means when in operation.