Pivotable Rotor Propulsion System for VTOL Power Optimization
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Solution Overview
Problem
VTOL air vehicles face significantly higher power requirements for vertical take-off, vertical landing, and hover compared to aerodynamic flight, leading to inefficiencies and increased weight and complexity in propulsion systems.
Innovation Solution
A propulsion system with a pivotable rotor and dual propulsion units, an internal combustion engine, and an electric motor, allowing for selective coupling and decoupling to optimize power usage between vertical and horizontal modes, reducing weight and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single propulsion unit is used for both vertical and horizontal thrust, then device complexity is reduced, but power requirements become excessively high for vertical operations
Solution Approach 1:
The propulsion system is divided into two separate propulsion units: a first propulsion unit (internal combustion engine) and a second propulsion unit (electric motor). Each unit can be independently coupled to the rotor, allowing the system to meet high power requirements for vertical operations without requiring a single oversized engine that would be inefficient for horizontal flight.
Solution Approach 2:
The rotor is designed to be universally coupled to either the first or second propulsion unit, allowing a single rotor design to serve both vertical and horizontal flight modes. This multi-functionality reduces overall system complexity while accommodating different power source requirements.
2Power
If high power is provided for vertical take-off and hover, then vertical performance is improved, but weight increases
Solution Approach 1:
By segmenting the propulsion system into two separate units with different power characteristics, the system can use the high-power internal combustion engine only when needed for vertical operations, rather than constantly carrying and operating a single high-power engine that would increase overall system weight and reduce efficiency during horizontal flight.
Solution Approach 2:
The system dynamically switches between propulsion units based on operational mode. The rotor is selectively coupled to the first propulsion unit during vertical operations and to the second propulsion unit during horizontal operations, optimizing the power-to-weight ratio for each flight phase.
3Adaptability or versatility
If the electric motor is continuously engaged, then VTOL operations are enabled, but power loss and heat-related performance issues increase
Solution Approach 1:
The coupling between the electric motor and rotor is made dynamic and selective rather than continuous. The second coupling mechanism allows the electric motor to be engaged only when VTOL operations are required, and disengaged during horizontal flight to eliminate parasitic power losses and heat generation associated with continuous operation.
Solution Approach 2:
The electric motor is extracted from the continuous propulsion chain and made selectively engageable through the second coupling mechanism. This allows the motor to be removed from the power transmission path during horizontal operations, eliminating energy losses associated with its continuous operation while preserving VTOL capability when needed.
Data Source
AI summary
Provided is a propulsion system, including a first propulsion unit, a second propulsion unit, a rotor, a first coupling and a second coupling. The first propulsion unit is configured for being fixedly mounted to an airframe. The rotor is configured for being pivotably mounted with respect to the first propulsion unit to allow selectively pivoting of the rotor from a horizontal mode to a vertical mode. The first coupling is configured for selectively coupling and decoupling the rotor with respect to the first propulsion unit. The second coupling is configured for selectively coupling and decoupling the rotor with respect to the second propulsion unit, independently of the first coupling.