Mobile Counterweights for Contra-Rotating Propeller Balancing
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Solution Overview
Problem
Existing balancing methods for coaxial non-streamlined contra-rotating propellers face challenges in reducing radial unbalance and increasing mass, particularly in systems with multiple propellers, where the rear propeller lacks a fixed structure for magnetic coils, leading to inefficiencies and additional mass not directly participating in balancing.
Innovation Solution
The method involves movably mounting counterweights on guiding slots coaxial to the hub envelopes, allowing their displacement to be controlled based on estimated unbalance, reducing additional mass and enabling direct participation in balancing, with mobile counterweights replacing multiple permanent magnets and magnetic coils, and allowing balancing of both propellers without relying on a fixed structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic coils and permanent magnets are used for adaptive balancing, then the propulsive system can be balanced under flight conditions, but the additional mass increases significantly
Solution Approach 1:
The patent extracts the magnetic coils from the fixed structure and relocates them to the rotating hub, allowing the balancing system to function independently of external fixed structures. This extraction enables the system to achieve adaptive balancing while reducing the overall mass by eliminating the need for heavy fixed mounting structures.
Solution Approach 2:
The patent implements a dynamic balancing system where counterweights can move along guiding slots in the hub, allowing real-time adjustment of the center of gravity position. This dynamic capability enables the system to adapt to changing flight conditions and maintain balancing effectiveness without requiring excessive mass.
2Adaptability or versatility
If magnetic coils are arranged close to the rear propeller, then adaptive balancing can be performed, but no fixed structure is available for mounting
Solution Approach 1:
The hub structure is designed to serve multiple functions: it provides mechanical support for the propeller blades, contains the magnetic coils for adaptive balancing, and incorporates guiding slots for counterweight movement. This multi-functionality eliminates the need for separate fixed mounting structures, particularly for the rear propeller.
Solution Approach 2:
The hub acts as an intermediary structure that enables adaptive balancing functionality without requiring external fixed structures. By integrating the magnetic coils and counterweight mechanisms into the hub itself, the system achieves the necessary adaptability while simplifying the overall device complexity.
3Device complexity
If counterweights are fixed in position, then the structure is simpler, but the propulsive system cannot be balanced under varying flight conditions
Solution Approach 1:
The patent transforms the static counterweight system into a dynamic one by allowing counterweights to move along guiding slots in the hub. This movement capability is controlled based on detected unbalance conditions, enabling the system to adapt to varying flight conditions and maintain balancing effectiveness without excessive structural complexity.
Solution Approach 2:
The patent implements a feedback control mechanism where sensors detect unbalance conditions and this information is used to control the position of movable counterweights. This feedback loop enables the system to automatically adjust to changing flight conditions and maintain optimal balancing performance.
Data Source
AI summary
According to the invention, at least one of the counterweights (40, 40.1, 40.2, 40.3, 40.4) is mobile mounted on a guiding slot (24, 34) coaxial to the hub envelope (22, 32) that surrounds the hub (21, 31) of the corresponding propeller (2, 3), the movement of said mobile counterweight (40, 40.1, 40.2, 40., 40.4) along said guiding slot (24, 34) being controlled on the basis of an estimation of the possible unbalance of said propulsive system (1).