Pivotable Propeller Blades for UAV Drag Reduction
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Solution Overview
Problem
Unmanned aerial vehicles (UAVs) face drag and stability issues due to propellers at rest, especially when not aligned normal to wind flow, which increases drag and affects performance during transit operations.
Innovation Solution
Propulsion units with pivotable blades and hubs that align with the direction of travel when not in use, reducing drag by stacking blades parallel to the wind flow, and deploy into operational position when the motor rotates, utilizing a spring mechanism and guide system to reposition the blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If propellers are kept stationary on the UAV during transit operations, then power consumption is reduced by shutting down motors, but drag increases and stability deteriorates due to propellers not being aligned with wind flow
Solution Approach 1:
The propeller blades are designed to be dynamically reconfigurable, transitioning from a fixed operational position during flight to a variable aligned position during transit. The blades can pivot and rotate to different angles based on wind flow direction, allowing the system to adapt its configuration rather than remaining static, thereby reducing drag while motors are shut down during transit operations
Solution Approach 2:
The system changes the orientation parameter of the propeller blades by allowing them to pivot and rotate to different angular positions. During transit, the blades can be positioned at various angles relative to the wind flow direction, optimizing their alignment to minimize drag. This parameter change enables the same propeller structure to serve different functional requirements
2Use of energy by moving object
If propellers are kept stationary on the UAV during transit operations, then power consumption is reduced by shutting down motors, but stability deteriorates due to propellers creating undesirable drag
Solution Approach 1:
The propeller system transitions from a static configuration to a dynamic one where blades can independently pivot and rotate. This dynamic capability allows the blades to actively align with wind flow during transit operations, maintaining aerodynamic stability even when motors are shut down, thereby preserving stability while reducing power consumption
3Productivity
If propellers are deployed into operational position when motors rotate, then propulsion efficiency is improved, but mechanical complexity increases due to spring mechanism and guide system
Solution Approach 1:
The propeller blades are designed to self-deploy into operational positions using spring mechanisms that automatically engage when motors rotate. The springs store potential energy during transit and convert it to kinetic energy to drive the blades into their correct operational angles, eliminating the need for complex active control systems or additional actuators, thereby achieving self-service deployment
Solution Approach 2:
Spring mechanisms and guide systems act as intermediary elements between the motor rotation and the blade positioning. These intermediaries translate the rotational motion of the motor into the appropriate angular positioning of the blades, facilitating smooth deployment while maintaining mechanical simplicity through passive elastic energy storage and geometric guidance
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 when motors are not operating, enhances stability, and allows for efficient transition between operational and non-operational states, improving UAV performance and energy conservation.
Implementation Method 1
utilizing a spring mechanism and guide system to reposition the blades
Implementation Method 2
Propulsion units with pivotable blades and hubs that align with the direction of travel when not in use, reducing drag by stacking blades parallel to the wind flow
Data Source
AI summary
Aerial vehicles may be equipped with propellers having pivotable blades that are configured to rotate when the propellers are not rotating under power. A pivotable blade may rotate about an axis of a propeller with respect to a hub until the pivotable blade is coaligned with a fixed blade. When the propeller is rotating, a lifting force from the blade may cause the blade to rotate to a deployed position that is not coaligned with the fixed blade.