VTOL Aircraft Rotor Blade System Active Passive Mode Switching
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Solution Overview
Problem
VTOL aircraft face inefficiencies in forward flight due to the need for continuous rotor operation and the weight and drag caused by propulsors during hovering, which can result in longer, heavier fixed wings for lift, making them inconvenient and less efficient.
Innovation Solution
A VTOL aircraft design featuring a rotor blade system that can switch between active and passive modes, where the rotor blades are rotatably mounted to provide lift in forward flight without continuous power, reducing drag and allowing for shorter, lighter fixed wings, and incorporating a dual contra-rotating pusher propeller for forward thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor blade system operates continuously in active mode to provide lift, then vertical take-off and landing capability is maintained, but energy consumption increases and weight increases due to required power systems
Solution Approach 1:
The rotor blade system dynamically switches between active and passive modes based on flight phase. During vertical take-off and landing, rotors operate in active mode with full power. During forward flight, rotors transition to passive mode, allowing the aircraft to exploit aerodynamic lift from fixed wings, thereby reducing energy consumption while maintaining VTOL capability when needed.
Solution Approach 2:
The rotor blade system serves multiple functions: providing lift during vertical flight modes (active mode) and serving as aerodynamic surfaces during forward flight (passive mode). This multi-functionality allows the same structure to support both VTOL operations and efficient forward flight without requiring separate systems, reducing overall weight while maintaining versatility.
2Force
If fixed wings are made longer and heavier to provide sufficient lift during forward flight, then lift capability is improved, but aircraft weight increases and compactness decreases
Solution Approach 1:
The aircraft employs variable geometry where the rotor blade system transitions between active and passive modes. During forward flight, rotors operate passively allowing fixed wings to generate lift, enabling shorter wing spans. During vertical flight, rotors engage actively to provide lift, compensating for reduced wing area. This dynamic adaptation allows reduced wing size without sacrificing overall lift capability.
Solution Approach 2:
The aircraft merges the lift-generating functions of both fixed wings and rotor blade systems into a unified approach. Rather than relying solely on large fixed wings for all flight phases, the design combines moderate-sized wings with a rotor system that supplements lift during vertical operations, achieving compactness while maintaining sufficient lift capability across all flight modes.
3Speed
If propulsors are continuously operated during forward flight, then forward thrust is maintained, but drag increases and efficiency decreases
Solution Approach 1:
The propulsion system employs periodic action by switching between active propeller operation and passive rotor operation based on flight phase. During vertical take-off and landing, propellers operate actively to provide thrust. During forward flight, the system transitions to passive rotor mode where aerodynamic forces provide forward motion, reducing propeller drag and improving efficiency while maintaining forward thrust capability when needed.
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 design enhances efficiency and reduces weight and drag by allowing the rotor blade system to provide lift in forward flight without active power, improving the aircraft's performance and compactness compared to traditional VTOL aircraft.
Implementation Method 1
a rotor blade system for providing lift in active and passive modes thereof
Implementation Method 2
the rotor blade system is configurable to provide lift in the passive mode during forward flight of the aircraft
Implementation Method 3
a propeller for providing forward thrust when driven by a power system of the aircraft
Data Source
Figure 1~2
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AI summary
A VTOL aircraft (100) comprises fixed wings (119A, 119B, 124A, 124B) and a rotor blade system (165A, 165B) for providing lift in active and passive modes thereof. Operation of the rotor blade system may be switched between the active mode in which the rotor blade system is driven by a power system of the aircraft and the passive mode in which the rotor blade system is not driven by the power system, the rotor blade system being configurable to provide lift in the passive mode during forward flight of the aircraft. The rotor blade system provides lift in the passive mode, allowing the fixed wings to be shorter than in the case where the rotor system provides lift during vertical take-off and landing but otherwise has no function, thus providing aircraft which is lighter, more compact and more efficient than similar aircraft of the prior art.