Shaft-Mounted Operators for Folding Propeller Blades
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Solution Overview
Problem
Unmanned aerial vehicles (UAVs) face drag and stability issues due to propellers at rest, especially when their axes are not aligned perpendicular to the wind flow, leading to increased drag and reduced efficiency during transit operations.
Innovation Solution
Propellers with pivotable or foldable blades that reposition themselves to align with a common side of the axis of rotation when not in use, mimicking a wind vane, reducing drag by aligning with the wind flow even when the propeller axis is not normal to it, and automatically returning to operational position when powered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the propeller blades are kept in a fixed position during transit, then the propeller structure is simple, but the drag increases and stability is reduced when the propeller axis is not aligned perpendicular to wind flow
Solution Approach 1:
The patent implements a dynamic blade positioning system where blades can pivot between a horizontal position during operation and a vertical folded position during transit. This dynamic reconfiguration allows the propeller to adapt to different flight phases, reducing drag during transit while maintaining operational effectiveness. The pivot mechanism enables the blade to move from a fixed static position to a variable position that optimizes aerodynamic performance based on flight conditions.
2Object-affected harmful factors
If the propeller blades are made foldable to reduce drag during transit, then drag is reduced and stability is enhanced, but the device complexity increases due to pivot mechanisms and operators
Solution Approach 1:
The patent employs spring operators that utilize elastic potential energy to automatically return the blades to their operational horizontal position after folding. The spring mechanism acts as a counterbalancing force that eliminates the need for complex motorized actuators or control systems. When the pivot mechanism is actuated to fold the blade, the spring stores energy and automatically reverses the motion, providing a simple passive return system that reduces overall device complexity while maintaining the drag-reduction benefit.
3Use of energy by moving object
If motors are shut down during transit to conserve energy, then energy consumption is reduced, but the propellers at rest create drag and stability issues
Solution Approach 1:
The patent converts the harmful effect of stationary propeller blades creating drag into a beneficial situation by enabling the blades to fold vertically during transit. When motors are shut down to conserve energy, the folded blade configuration aligns with the wind flow direction, transforming what would be a drag-inducing stationary propeller into an aerodynamically efficient configuration. This allows the system to simultaneously achieve energy conservation and drag reduction during transit operations.
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 reduces drag and enhances stability by ensuring blades are aligned opposite to the wind flow when not in use, conserving energy and improving flight efficiency during transit phases.
Implementation Method 1
Where a propeller at rest is aligned normal to a direction of wind flow, the propeller may naturally align in a direction parallel to that of the wind flow, or be urged into that direction, thereby reducing the extent of drag created by the propeller.
Implementation Method 2
When the propeller begins to rotate, centrifugal forces may cause a folded or pivoted blade to return to an opposite (or antipodal) side of a hub from a fixed blade, or to a normal operating position with respect to the hub.
Data Source
AI summary
Aerial vehicles may be equipped with propellers having pivotable blades that are configured to rotate or fold when the propellers are not rotating under power. A pivotable blade may rotate about an axis of a propeller with respect to a hub in the presence of wind flow until the pivotable blade is coaligned with a fixed blade, in a direction opposite to the wind flow. A pivotable blade may also fold over a hub of a propeller in the presence of wind flow, with the pivotable blade and a fixed blade being oriented in directions opposite to the wind flow. A center of mass of the pivotable blade may be caused to be on the same side of an axis as a center of mass of a fixed blade, even where the axis is not normal to the wind flow, thereby reducing an amount of drag generated by the propeller.