Offset Propeller Rotor Blade Pitch Control
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Solution Overview
Problem
Conventional rotor systems in rotorcraft, such as helicopters, rely on complex mechanical systems like swashplates and pitch control rods to achieve collective and cyclic pitch changes, adding weight and complexity, and require additional components like engines and tail rotors for operation.
Innovation Solution
The implementation of an offset propeller system where multiple electrically powered propellers are strategically placed on the rotor blades to control blade pitch and provide in-plane driving/braking forces, eliminating the need for a swashplate system and additional rotors by using offset propellers on the upper and lower surfaces of the blades to generate thrust and twist, allowing for precise control of pitch angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional mechanical systems (swashplates and pitch control rods) are used to achieve collective and cyclic pitch changes, then pitch control is accomplished, but weight and device complexity increase significantly
Solution Approach 1:
The patent replaces the conventional mechanical swashplate and pitch control rod system with an aerodynamic system using offset propellers. Electric motors mounted on the rotor blades drive offset propellers that generate aerodynamic forces to control blade pitch angles, eliminating complex mechanical linkages and reducing system weight while maintaining pitch control functionality
Solution Approach 2:
The invention extracts and eliminates the heavy mechanical swashplate system from the rotorcraft. By using independently controlled offset propellers on each blade, the patent removes the need for the entire swashplate assembly and its associated mechanical linkages, significantly reducing device complexity
2Power
If conventional rotor systems include engine, transmission, drive system and tail rotor, then the rotor system can be driven and torques balanced, but weight and device complexity increase
Solution Approach 1:
The patent segments the rotor driving function from the central engine-transmission system. Each rotor blade is equipped with its own electric motor and offset propeller system, allowing independent control of each blade. This segmentation eliminates the need for a centralized transmission system and tail rotor, reducing overall system complexity while maintaining driving capability
Solution Approach 2:
The offset propeller system serves multiple functions: it provides in-plane driving forces to rotate the rotor, generates braking forces to control rotor speed, and creates aerodynamic moments to control blade pitch angles. This multi-functionality replaces the separate engine, transmission, and tail rotor systems in conventional rotorcraft
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 configuration enables efficient collective and cyclic pitch control without the need for heavy mechanical systems, reducing weight and complexity while providing precise control over rotorcraft movements, including the ability to drive or brake the rotor system.
Implementation Method 1
the thrust of the at least one offset propeller unit generates a force to cause the at least one blade to rotate about the shaft axis
Implementation Method 2
a moment about the blade twist axis of the at least one blade to cause the blade to have a blade pitch angle
Data Source
AI summary
Example embodiments provide a propeller apparatus comprising at least one blade able to twist along a blade twist axis, a hub, a shaft connected to the hub and configured to rotate such that the at least one blade rotates about a shaft axis, and at least one offset propeller unit located in at least one of an upper surface and/or a lower surface of the at least one blade, the at least one offset propeller unit configured to provide thrust. In the propeller apparatus the thrust of the at least one offset propeller unit generates a force to cause the at least one blade to rotate about the shaft axis, and a moment about the blade twist axis of the at least one blade to cause the blade to have a blade pitch angle.