VTOL Rotor Blade Orientation for Cruise Drag Reduction
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Solution Overview
Problem
VTOL aircraft face challenges in minimizing airflow disturbance over wings during wingborne flight due to the presence of rotors required for thrustborne operations, which degrade vehicle performance by generating drag during cruise flight.
Innovation Solution
The aircraft employs a series of port and starboard rotor units with axially opposed rotor blades that can be angularly positioned by a logic control unit to minimize airflow disruption over fixed-position wings during cruise flight, using rotor position sensors and motor control units to adjust the blades to optimal positions based on flight phase and altitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotors are kept rotating to generate thrust during cruise flight, then vertical thrust capability is maintained, but drag increases and vehicle performance degrades
Solution Approach 1:
The rotor blade angular position is dynamically adjusted based on flight phase. During cruise flight, the blades are rotated to a specific angular position that minimizes drag while maintaining the ability to generate thrust when needed. This dynamic repositioning allows the system to adapt between different operational requirements without sacrificing either vertical thrust capability or cruise efficiency
Solution Approach 2:
The angular position parameter of the rotor blades is changed during cruise flight to optimize performance. By rotating the blades to a specific angular orientation, the system modifies the aerodynamic characteristics to reduce drag while preserving thrust generation capability, effectively changing the operational state of the rotors without stopping them
2Loss of energy
If rotors are stopped during cruise flight to minimize drag, then vehicle performance improves, but vertical thrust capability is lost
Solution Approach 1:
Instead of completely stopping the rotors, the system dynamically adjusts the blade angular position to a cruise-optimized orientation. This dynamic adjustment maintains rotational motion and thrust capability while minimizing drag, allowing rapid transition between cruise and vertical flight modes without the need to fully stop or restart the rotors
Solution Approach 2:
The rotor system is designed to perform multiple functions: generating vertical thrust during takeoff and landing, and minimizing drag during cruise flight. By adjusting the angular position of the blades, the same rotor system universally serves both purposes without requiring separate systems for different flight phases
3Reliability
If multiple rotors are used for thrustborne flight, then vertical lift capability is improved, but device complexity increases
Solution Approach 1:
Multiple rotor units are designed with identical multi-functional capabilities, where each rotor can independently generate vertical thrust or be positioned to minimize drag. This universality allows the system to use multiple rotors for enhanced vertical lift capability while managing complexity through standardized, interchangeable components that perform the same dual functions
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 solution allows for efficient vertical takeoff and landing while minimizing drag and maintaining optimal wing performance by actively aligning rotor blades to reduce airflow disturbance, enhancing the aircraft's overall efficiency and safety during various flight phases.
Implementation Method 1
A series of port and starboard rotor units are provided, each of which includes axially opposed rotor blades, and a motor to rotate the rotor blades and provide vertical thrust to the aircraft
Implementation Method 2
controllably sets an angular position of the opposed rotor blades along a position axis relative to the longitudinal axis of the aircraft in response to determining an optimal position of the rotor blades during cruise flight operation to thereby minimize airflow disruption over the fixed-position wings
Data Source
AI summary
Vertical takeoff and landing (VTOL) aircraft are provided with fixed-position port and starboard wings extending laterally from an elongate fuselage having an empennage at an aft end of the fuselage and a propeller to provide horizontal thrust to the aircraft in a direction of the longitudinal axis thereof. A series of port and starboard rotor units are provided, each of which includes axially opposed rotor blades, and a motor to rotate the rotor blades and provide vertical thrust to the aircraft. A logic control unit (LCU) controllably sets an angular position of the opposed rotor blades along a position axis relative to the longitudinal axis of the aircraft in response to determining an optimal position of the rotor blades during cruise flight operation to thereby minimize airflow disruption over the fixed-position wings.