Interconnected Propeller Blades Passive Pitch Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fixed pitch propellers experience inadequate lift and drag distribution during forward flight, leading to increased power consumption and complex, heavy, and costly pitch adjustment mechanisms in articulated rotor assemblies.
Innovation Solution
A propeller assembly with interconnected blades featuring a common pitch axis, allowing passive pitch adjustment in response to aerodynamic forces, which transfers moments between blades to homogenize lift distribution and reduce drag, eliminating the need for active actuation means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed pitch propellers are used, then the structure is simple, but the lift and drag distribution is inadequate during forward flight
Solution Approach 1:
The patent applies the dynamics principle by enabling the propeller blades to rotate passively around a pitch axis, transforming the static fixed-pitch design into a dynamic system that automatically adjusts blade pitch in response to aerodynamic forces during forward flight
Solution Approach 2:
The patent implements self-service by allowing the blades to automatically adjust their pitch angle through passive rotation around the pitch axis, using aerodynamic forces themselves to control the pitch without requiring external actuators or complex control systems
2Productivity
If articulated rotor assemblies with cyclic pitch actuation are used, then the lift and drag distribution is improved, but the device becomes complex, heavy and costly
Solution Approach 1:
The patent extracts the active actuation mechanisms from the system, retaining only the essential pitch axis and connection means, thereby eliminating complex, heavy, and costly pitch adjustment devices while preserving the beneficial lift and drag distribution through passive blade rotation
Solution Approach 2:
The patent replaces active cyclic pitch actuation with a self-service system where blades automatically adjust their pitch through passive rotation around the pitch axis in response to aerodynamic forces, eliminating the need for complex control mechanisms
3Productivity
If active pitch adjustment devices are used, then the lift distribution is homogenized, but the weight and cost increase
Solution Approach 1:
The patent implements self-service by allowing blades to automatically homogenize lift distribution through passive pitch adjustment around the pitch axis, eliminating the need for heavy active actuation systems while maintaining effective lift management during forward flight
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 solution reduces power consumption, simplifies design, minimizes flapping moments, and decreases overall weight, leading to increased endurance and reduced acoustic emissions during non-axial inflow fields.
Implementation Method 1
a passive pitch adjustment of the at least two propeller blades around the common pitch axis in response to aerodynamic forces acting on the at least two propeller blades
Implementation Method 2
The associated connection means is adapted to transfer moments between the at least two propeller blades to each other
Data Source
AI summary
A propeller assembly with at least two propeller blades that are interconnected by associated connection means, the associated connection means defining a common pitch axis for the at least two propeller blades in operation, each one of the at least two propeller blades comprising associated leading and trailing edges that define a respective chord and quarter chord line thereof, wherein the common pitch axis is arranged with a predetermined offset relative to the quarter chord line of each one of the at least two propeller blades, and wherein the associated connection means is adapted to enable, at least in operation in a non-axial inflow field, a passive pitch adjustment of the at least two propeller blades around the common pitch axis.