VTOL Aircraft Centrifugal Compressor with Pivoting Thrust Ducts
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Solution Overview
Problem
Current VTOL fixed wing aircraft face challenges in achieving high-speed sustained flight, hover efficiency, and cruise lift-to-drag ratio due to issues with open-exposed rotors or propellers, which are hazardous, vulnerable to damage, and produce excessive noise and adverse yaw tendencies.
Innovation Solution
A vertical thrust propulsion system utilizing a centrifugal compressor assembly with articulable thrust augmentation ducts, where air flow plenums and intakes are strategically positioned to enable efficient vertical and forward flight modes without exposed rotating engines or propellers, reducing noise and vulnerability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If open-exposed rotors or propellers are used for VTOL flight, then vertical lift capability is achieved, but safety and vulnerability increase due to exposed rotating components in the human safety zone
Solution Approach 1:
A shroud structure acts as an intermediary between the rotor and the external environment, containing the rotating blades within a protected enclosure. This shroud prevents direct exposure of the rotor while still allowing air flow for lift generation, thereby reducing safety hazards and vulnerability to foreign objects.
Solution Approach 2:
The rotor system is nested within a shroud structure, creating a hierarchical arrangement where the rotating blades are contained inside the protective enclosure. This nesting approach allows the rotor to function while being protected from external hazards and preventing exposure to the external environment.
2Reliability
If ducted fans with perimeter rotating blades are used, then VTOL capability is achieved, but drag increases and horizontal flight performance deteriorates
Solution Approach 1:
The duct configuration is made adjustable or optimized for different flight phases. The duct geometry and airflow characteristics are dynamically adapted to reduce drag during horizontal flight while maintaining effective lift generation during VTOL operations, allowing the system to perform optimally in both regimes.
Solution Approach 2:
Different sections of the duct structure have optimized local characteristics - the intake and exhaust areas are designed with specific geometries that minimize drag during forward flight, while the overall duct structure maintains the enclosed rotor configuration needed for VTOL capability.
3Reliability
If large rotor blades are used for vertical lift, then hover capability is achieved, but noise increases due to blade interaction with retreating airflow
Solution Approach 1:
The shroud structure acts as an acoustic barrier and airflow mediator, containing the rotor blades within an enclosure that reduces the interaction between retreating blades and external airflow. This containment minimizes the generation of mid-range acoustic signatures while still allowing sufficient air flow for hover capability.
4Reliability
If rotating mechanisms are used for VTOL transition, then vertical lift is achieved, but center of gravity control becomes difficult and device complexity increases
Solution Approach 1:
The rotation mechanism is extracted or eliminated from the system. Instead of using rotating propellers or ducted fans that require complex powered cross shafting, the design uses a stationary duct configuration with fixed rotor blades that achieve VTOL transition through aerodynamic forces alone, significantly reducing mechanical complexity.
5Reliability
If exposed rotors are used for VTOL flight, then vertical lift capability is achieved, but vulnerability to foreign objects and damage increases
Solution Approach 1:
The shroud structure serves as a protective intermediary between the rotor system and the external environment, preventing foreign objects from entering the rotor area and protecting against small arms fire and debris in hostile environments while maintaining VTOL operational 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 VTOL fixed wing aircraft to achieve high-speed sustained flight, improved hover efficiency, and enhanced cruise performance with reduced noise and adverse yaw issues, while maintaining conventional seating and eliminating the need for large exposed rotating components.
Implementation Method 1
A centrifugal compressor assembly has upper and lower impellers disposed for counter-rotation about a generally vertical compressor axis. Each impeller has a plurality of vanes contoured to draw air through the respective upper and lower ends of the compressor housing, and to drive air radially outwardly into the peripheral collector.
Implementation Method 2
An articulable thrust augmentation duct is operatively associated with at least one of the main air outlets. The thrust augmentation duct is supported within an articulation mount that enables the thrust augmentation duct to pivot between a generally downwardly pointing VTOL position and a generally rearwardly pointing flight position.
Implementation Method 3
An air flow plenum extends between a plurality of main air intakes and a plurality of main air outlets. A peripheral collector is in direct fluid communication with the plurality of main air outlets.
Data Source
AI summary
A fixed wing type Vertical Take-Off and Landing (VTOL) aircraft retains a conventional seating arrangement and utilizes a single point VTOL lift source, in the form of a counter-rotating centrifugal compressor assembly having co-axially aligned upper and lower impellers. Air is fed to the upper impeller through a central intake, and to the lower impeller through either a VTOL mode intake or a flight mode intake. Air is exhausted from the impellers through a plurality of main air outlets. Each main air outlet is fitted with a thrust augmentation duct that can be pivoted downward for VTOL, or rearward for forward flight. A controller alternately closes the flight mode intake when the thrust augmentation ducts are in the downwardly pointing VTOL position, and closes the VTOL mode intakes when the thrust augmentation ducts are in the rearwardly pointing flight position.